Fascicles and the interfascicular matrix show decreased fatigue life with ageing in energy storing tendons.

PubMed

Thorpe, Chavaunne T; Riley, Graham P; Birch, Helen L; Clegg, Peter D; Screen, Hazel R C

2017-07-01

Tendon is composed of rope-like fascicles bound together by interfascicular matrix (IFM). The IFM is critical for the function of energy storing tendons, facilitating sliding between fascicles to allow these tendons to cyclically stretch and recoil. This capacity is required to a lesser degree in positional tendons. We have previously demonstrated that both fascicles and IFM in energy storing tendons have superior fatigue resistance compared with positional tendons, but the effect of ageing on the fatigue properties of these different tendon subunits has not been determined. Energy storing tendons become more injury-prone with ageing, indicating reduced fatigue resistance, hence we tested the hypothesis that the decline in fatigue life with ageing in energy storing tendons would be more pronounced in the IFM than in fascicles. We further hypothesised that tendon subunit fatigue resistance would not alter with ageing in positional tendons. Fascicles and IFM from young and old energy storing and positional tendons were subjected to cyclic fatigue testing until failure, and mechanical properties were calculated. The results show that both IFM and fascicles from the SDFT exhibit a similar magnitude of reduced fatigue life with ageing. By contrast, the fatigue life of positional tendon subunits was unaffected by ageing. The age-related decline in fatigue life of tendon subunits in energy storing tendons is likely to contribute to the increased risk of injury in aged tendons. Full understanding of the mechanisms resulting in this reduced fatigue life will aid in the development of treatments and interventions to prevent age-related tendinopathy. Understanding the effect of ageing on tendon-structure function relationships is crucial for the development of effective preventative measures and treatments for age-related tendon injury. In this study, we demonstrate for the first time that the fatigue resistance of the interfascicular matrix decreases with ageing in energy storing tendons. This is likely to contribute to the increased risk of injury in aged tendons. Full understanding of the mechanisms that result in this reduced fatigue resistance will aid in the development of treatments and interventions to prevent age-related tendinopathy. Copyright © 2017. Published by Elsevier Ltd.

Tendon injuries

PubMed Central

Wu, Fan; Nerlich, Michael; Docheva, Denitsa

2017-01-01

Tendons connect muscles to bones, ensuring joint movement. With advanced age, tendons become more prone to degeneration followed by injuries. Tendon repair often requires lengthy periods of rehabilitation, especially in elderly patients. Existing medical and surgical treatments often fail to regain full tendon function. The development of novel treatment methods has been hampered due to limited understanding of basic tendon biology. Recently, it was discovered that tendons, similar to other mesenchymal tissues, contain tendon stem/progenitor cells (TSPCs) which possess the common stem cell properties. The current strategies for enhancing tendon repair consist mainly of applying stem cells, growth factors, natural and artificial biomaterials alone or in combination. In this review, we summarise the basic biology of tendon tissues and provide an update on the latest repair proposals for tendon tears. Cite this article: EFORT Open Rev 2017;2:332-342. DOI: 10.1302/2058-5241.2.160075 PMID:28828182

Tendon injuries of the hand

PubMed Central

Schöffl, Volker; Heid, Andreas; Küpper, Thomas

2012-01-01

Tendon injuries are the second most common injuries of the hand and therefore an important topic in trauma and orthopedic patients. Most injuries are open injuries to the flexor or extensor tendons, but less frequent injuries, e.g., damage to the functional system tendon sheath and pulley or dull avulsions, also need to be considered. After clinical examination, ultrasound and magnetic resonance imaging have proved to be important diagnostic tools. Tendon injuries mostly require surgical repair, dull avulsions of the distal phalanges extensor tendon can receive conservative therapy. Injuries of the flexor tendon sheath or single pulley injuries are treated conservatively and multiple pulley injuries receive surgical repair. In the postoperative course of flexor tendon injuries, the principle of early passive movement is important to trigger an “intrinsic” tendon healing to guarantee a good outcome. Many substances were evaluated to see if they improved tendon healing; however, little evidence was found. Nevertheless, hyaluronic acid may improve intrinsic tendon healing. PMID:22720265

Evolution of the Achilles tendon: The athlete's Achilles heel?

PubMed

Malvankar, S; Khan, W S

2011-12-01

The Achilles tendon is believed to have first developed two million years ago enabling humans to run twice as fast. However if the Achilles tendon is so important in terms of evolution, then why is this tendon so prone to injury - especially for those more active like athletes. The Achilles tendon had an integral role in evolving apes from a herbivorous diet to early humans who started hunting for food over longer distances, resulting in bipedal locomotion. Evolutionary advantages of the Achilles tendon includes it being the strongest tendon in the body, having an energy-saving mechanism for fast locomotion, allows humans to jump and run, and additionally is a spring and shock absorber during gait. Considering these benefits it is therefore not surprising that studies have shown athletes have thicker Achilles tendons than subjects who are less active. However, contradictory to these findings that show the importance of the Achilles tendon for athletes, it is well known that obtaining an Achilles tendon injury for an athlete can be career-altering. A disadvantage of the Achilles tendon is that the aetiology of its pathology is complicated. Achilles tendon ruptures are believed to be caused by overloading the tensed tendon, like during sports. However studies have also shown athlete Achilles tendon ruptures to have degenerative changes in the tendon. Other flaws of the Achilles tendon are its non-uniform vascularity and incomplete repair system which may suggest the Achilles tendon is on the edge of evolution. Research has shown that there is a genetic influence on the predisposition a person has towards Achilles tendon injuries. So if this tendon is here to stay in our anatomy, and it probably is due to the slow rate of evolution in humans, research in genetic modification could be used to decrease athletes' predisposition to Achilles tendinopathy. Copyright © 2011 Elsevier Ltd. All rights reserved.

It's positive to be negative: Achilles tendon work loops during human locomotion.

PubMed

Zelik, Karl E; Franz, Jason R

2017-01-01

Ultrasound imaging is increasingly used with motion and force data to quantify tendon dynamics during human movement. Frequently, tendon dynamics are estimated indirectly from muscle fascicle kinematics (by subtracting muscle from muscle-tendon unit length), but there is mounting evidence that this Indirect approach yields implausible tendon work loops. Since tendons are passive viscoelastic structures, when they undergo a loading-unloading cycle they must exhibit a negative work loop (i.e., perform net negative work). However, prior studies using this Indirect approach report large positive work loops, often estimating that tendons return 2-5 J of elastic energy for every 1 J of energy stored. More direct ultrasound estimates of tendon kinematics have emerged that quantify tendon elongations by tracking either the muscle-tendon junction or localized tendon tissue. However, it is unclear if these yield more plausible estimates of tendon dynamics. Our objective was to compute tendon work loops and hysteresis losses using these two Direct tendon kinematics estimates during human walking. We found that Direct estimates generally resulted in negative work loops, with average tendon hysteresis losses of 2-11% at 1.25 m/s and 33-49% at 0.75 m/s (N = 8), alluding to 0.51-0.98 J of tendon energy returned for every 1 J stored. We interpret this finding to suggest that Direct approaches provide more plausible estimates than the Indirect approach, and may be preferable for understanding tendon energy storage and return. However, the Direct approaches did exhibit speed-dependent trends that are not consistent with isolated, in vitro tendon hysteresis losses of about 5-10%. These trends suggest that Direct estimates also contain some level of error, albeit much smaller than Indirect estimates. Overall, this study serves to highlight the complexity and difficulty of estimating tendon dynamics non-invasively, and the care that must be taken to interpret biological function from current ultrasound-based estimates.

Tendon Mineralization Is Progressive and Associated with Deterioration of Tendon Biomechanical Properties, and Requires BMP-Smad Signaling in the Mouse Achilles Tendon Injury Model

PubMed Central

Zhang, Kairui; Asai, Shuji; Hast, Michael W.; Liu, Min; Usami, Yu; Iwamoto, Masahiro; Soslowsky, Louis J.; Enomoto-Iwamoto, Motomi

2016-01-01

Ectopic tendon mineralization can develop following tendon rupture or trauma surgery. The pathogenesis of ectopic tendon mineralization and its clinical impact have not been fully elucidated yet. In this study, we utilized a mouse Achilles tendon injury model to determine whether ectopic tendon mineralization alters the biomechanical properties of the tendon and whether BMP signaling is involved in this condition. A complete transverse incision was made at the midpoint of the right Achilles tendon in 8-week-old CD1 mice and the gap was left open. Ectopic cartilaginous mass formation was found in the injured tendon by 4 weeks post-surgery and ectopic mineralization was detected at 8–10 weeks post-surgery. Ectopic mineralization grew over time and volume of the mineralized materials of 25-weeks samples was about 2.5 fold bigger than that of 10-weeks samples, indicating that injury-induced ectopic tendon mineralization is progressive. In vitro mechanical testing showed that max force, max stress and mid-substance modulus in the 25-weeks samples were significantly lower than the 10-weeks samples. We observed substantial increases in expression of bone morphogenetic protein family genes in injured tendons 1 week post-surgery. Immunohistochemical analysis showed that phosphorylation of both Smad1 and Smad3 were highly increased in injured tendons as early as 1 week post-injury and remained high in ectopic chondrogenic lesions 4 weeks post-injury. Treatment with the BMP receptor kinase inhibitor (LDN193189) significantly inhibited injury-induced tendon mineralization. These findings indicate that injury-induced ectopic tendon mineralization is progressive, involves BMP signaling and associated with deterioration of tendon biomechanical properties. PMID:26825318

Angiopoietin-like 4 promotes angiogenesis in the tendon and is increased in cyclically loaded tendon fibroblasts.

PubMed

Mousavizadeh, Rouhollah; Scott, Alex; Lu, Alex; Ardekani, Gholamreza S; Behzad, Hayedeh; Lundgreen, Kirsten; Ghaffari, Mazyar; McCormack, Robert G; Duronio, Vincent

2016-06-01

Angiopoietin-like 4 (ANGPTL4) modulates tendon neovascularization. Cyclic loading stimulates the activity of transforming growth factor-β and hypoxia-inducible factor 1α and thereby increases the expression and release of ANGPTL4 from human tendon cells. Targeting ANGPTL4 and its regulatory pathways is a potential avenue for regulating tendon vascularization to improve tendon healing or adaptation. The mechanisms that regulate angiogenic activity in injured or mechanically loaded tendons are poorly understood. The present study examined the potential role of angiopoietin-like 4 (ANGPTL4) in the angiogenic response of tendons subjected to repetitive mechanical loading or injury. Cyclic stretching of human tendon fibroblasts stimulated the expression and release of ANGPTL4 protein via transforming growth factor-β (TGF-β) and hypoxia-inducible factor 1α (HIF-1α) signalling, and the released ANGPTL4 was pro-angiogenic. Angiogenic activity was increased following ANGPTL4 injection into mouse patellar tendons, whereas the patellar tendons of ANGPTL4 knockout mice displayed reduced angiogenesis following injury. In human rotator cuff tendons, the expression of ANGPTL4 was correlated with the density of tendon endothelial cells. To our knowledge, this is the first study characterizing a role of ANGPTL4 in the tendon. ANGPTL4 may assist in the regulation of vascularity in the injured or mechanically loaded tendon. TGF-β and HIF-1α comprise two signalling pathways that modulate the expression of ANGPTL4 by mechanically stimulated tendon fibroblasts and, in the future, these could be manipulated to influence tendon healing or adaptation. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

Tendon allograft sterilized by peracetic acid/ethanol combined with gamma irradiation.

PubMed

Zhou, Mo; Zhang, Naili; Liu, Xiaoming; Li, Youchen; Zhang, Yumin; Wang, Xusheng; Li, Baoming; Li, Baoxing

2014-07-01

Research and clinical applications have demonstrated that the effects of tendon allografts are comparable to those of autografts when reconstructing injured tendons or ligaments, but allograft safety remains problematic. Sterilisation could eliminate or decrease the possibility of disease transmission, but current methods seldom achieve satisfactory sterilisation without affecting the mechanical properties of the tendon. Peracetic acid-ethanol in combination with low-dose gamma irradiation (PE-R) would inactivate potential deleterious microorganisms without affecting mechanical and biocompatible properties of tendon allograft. Controlled laboratory design. HIV, PPV, PRV and BVDV inactivation was evaluated. After verifying viral inactivation, the treated tendon allografts were characterised by optical microscopy, scanning electron microscopy and tensile testing, and the cytocompatibility was assessed with an MTT assay and by subcutaneous implantation. Effective and efficient inactivation of HIV, PPV, PRV and BVDV was observed. Histological structure and ultrastructure were unchanged in the treated tendon allograft, which also exhibited comparable biomechanical properties and good biocompatibility. The preliminary results confirmed our hypothesis and demonstrated that the PE-R tendon allograft has significant potential as an alternative to ligament/tendon reconstruction. Tendon allografts have been extensively used in ligament reconstruction and tendon repair. However, current sterilisation methods have various shortcomings, so PE-R has been proposed. This study suggests that PE-R tendon allograft has great potential as an alternative for ligament/tendon reconstruction. Sterilisation has been a great concern for tendon allografts. However, most sterilisation methods cannot inactivate viruses and bacteria without impairing the mechanical properties of the tendon allograft. Peracetic acid/ethanol with gamma irradiation can effectively inactivate viruses and bacteria. Meanwhile, tendon allografts sterilised by this method maintain their physiological tendon structure, biomechanical integrity and good compatibility.

Structure-function relationships in tendons: a review

PubMed Central

Benjamin, M; Kaiser, E; Milz, S

2008-01-01

The purpose of the current review is to highlight the structure-function relationship of tendons and related structures to provide an overview for readers whose interest in tendons needs to be underpinned by anatomy. Because of the availability of several recent reviews on tendon development and entheses, the focus of the current work is primarily directed towards what can best be described as the ‘tendon proper’ or the ‘mid-substance’ of tendons. The review covers all levels of tendon structure from the molecular to the gross and deals both with the extracellular matrix and with tendon cells. The latter are often called ‘tenocytes’ and are increasingly recognized as a defined cell population that is functionally and phenotypically distinct from other fibroblast-like cells. This is illustrated by their response to different types of mechanical stress. However, it is not only tendon cells, but tendons as a whole that exhibit distinct structure-function relationships geared to the changing mechanical stresses to which they are subject. This aspect of tendon biology is considered in some detail. Attention is briefly directed to the blood and nerve supply of tendons, for this is an important issue that relates to the intrinsic healing capacity of tendons. Structures closely related to tendons (joint capsules, tendon sheaths, pulleys, retinacula, fat pads and bursae) are also covered and the concept of a ‘supertendon’ is introduced to describe a collection of tendons in which the function of the whole complex exceeds that of its individual members. Finally, attention is drawn to the important relationship between tendons and fascia, highlighted by Wood Jones in his concept of an ‘ectoskeleton’ over half a century ago – work that is often forgotten today. PMID:18304204

Conditioning of the Achilles tendon via ankle exercise improves correlations between sonographic measures of tendon thickness and body anthropometry.

PubMed

Wearing, Scott C; Grigg, Nicole L; Hooper, Sue L; Smeathers, James E

2011-05-01

Although conditioning is routinely used in mechanical tests of tendon in vitro, previous in vivo research evaluating the influence of body anthropometry on Achilles tendon thickness has not considered its potential effects on tendon structure. This study evaluated the relationship between Achilles tendon thickness and body anthropometry in healthy adults both before and after resistive ankle plantarflexion exercise. A convenience sample of 30 healthy male adults underwent sonographic examination of the Achilles tendon in addition to standard anthropometric measures of stature and body weight. A 10-5 MHz linear array transducer was used to acquire longitudinal sonograms of the Achilles tendon, 20 mm proximal to the tendon insertion. Participants then completed a series (90-100 repetitions) of conditioning exercises against an effective resistance between 100% and 150% body weight. Longitudinal sonograms were repeated immediately on completion of the exercise intervention, and anteroposterior Achilles tendon thickness was determined. Achilles tendon thickness was significantly reduced immediately following conditioning exercise (t = 9.71, P < 0.001), resulting in an average transverse strain of -18.8%. In contrast to preexercise measures, Achilles tendon thickness was significantly correlated with body weight (r = 0.72, P < 0.001) and to a lesser extent height (r = 0.45, P = 0.01) and body mass index (r = 0.63, P < 0.001) after exercise. Conditioning of the Achilles tendon via resistive ankle exercises induces alterations in tendon structure that substantially improve correlations between Achilles tendon thickness and body anthropometry. It is recommended that conditioning exercises, which standardize the load history of tendon, are employed before measurements of sonographic tendon thickness in vivo.

A wrist tendon travel assessment of hand movements associated with industrial repetitive activities.

PubMed

Ugbolue, U Chris; Nicol, Alexander C

2012-01-01

To investigate slow and fast paced industrial activity hand repetitive movements associated with carpal tunnel syndrome where movements are evaluated based on finger and wrist tendon travel measurements. Nine healthy subjects were recruited for the study aged between 23 and 33 years. Participants mimicked an industrial repetitive task by performing the following activities: wrist flexion and extension task, palm open and close task; and pinch task. Each task was performed for a period of 5 minutes at a slow (0.33 Hz) and fast (1 Hz) pace for a duration of 3 minutes and 2 minutes respectively. Tendon displacement produced higher flexor digitorum superficialis (FDS) tendon travel when compared to the flexor digitorum profundus (FDP) tendons. The left hand mean (SD) tendon travel for the FDS tendon and FDP tendon were 11108 (5188) mm and 9244 (4328) mm while the right hand mean tendon travel (SD) for the FDS tendon and FDP tendon were 9225 (3441) mm and 7670 (2856) mm respectively. Of the three tasks mimicking an industrial repetitive activity, the wrist flexion and extension task produced the most tendon travel. The findings may be useful to researchers in classifying the level of strenuous activity in relation to tendon travel.

Achilles tendon: US examination

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fornage, B.D.

Real-time ultrasonography (US) using linear-array probes and a stand-off pad as a ''waterpath'' was performed to evaluate the Achilles tendon in 67 patients (including 24 athletes) believed to have acute or chronic traumatic or inflammatory pathologic conditions. Tendons in 23 patients appeared normal on US scans. The 44 abnormal tendons comprised five complete and four partial ruptures, seven instances of postoperative change, and 28 cases of tendonitis. US depiction of the inner structure of the tendon resulted in the diagnosis of focal abnormalities, including partial ruptures, nodules, and calcifications. Tendonitis was characterized by enlargement and decreased echogenicity of the tendon.more » The normal US appearance of the Achilles tendon is described.« less

Doppler ultrasonography of the anterior knee tendons in elite badminton players: colour fraction before and after match.

PubMed

Koenig, M J; Torp-Pedersen, S; Boesen, M I; Holm, C C; Bliddal, H

2010-02-01

Anterior knee tendon problems are seldom reported in badminton players although the game is obviously stressful to the lower extremities. Painful anterior knee tendons are common among elite badminton players. The anterior knee tendons exhibit colour Doppler activity. This activity increases after a match. Painful tendons have more Doppler activity than tendons without pain. Cohort study. 72 elite badminton players were interviewed about training, pain and injuries. The participants were scanned with high-end ultrasound equipment. Colour Doppler was used to examine the tendons of 64 players before a match and 46 players after a match. Intratendinous colour Doppler flow was measured as colour fraction (CF). The tendon complex was divided into three loci: the quadriceps tendon, the proximal patellar tendon and the insertion on the tibial tuberosity. Interview: Of the 72 players, 62 players had problems with 86 tendons in the lower extremity. Of these 86 tendons, 48 were the anterior knee tendons. Ultrasound: At baseline, the majority of players (87%) had colour Doppler flow in at least one scanning position. After a match, the percentage of the knee complexes involved did not change. CF increased significantly in the dominant leg at the tibial tuberosity; single players had a significantly higher CF after a match at the tibial tuberosity and in the patellar tendon both before and after a match. Painful tendons had the highest colour Doppler activity. Most elite badminton players had pain in the anterior knee tendons and intratendinous Doppler activity both before and after match. High levels of Doppler activity were associated with self-reported ongoing pain.

Effects of running on human Achilles tendon length-tension properties in the free and gastrocnemius components.

PubMed

Lichtwark, Glen A; Cresswell, Andrew G; Newsham-West, Richard J

2013-12-01

The elastic properties of the human Achilles tendon are important for locomotion; however, in vitro tests suggest that repeated cyclic contractions lead to tendon fatigue - an increase in length in response to stress applied. In vivo experiments have not, however, demonstrated mechanical fatigue in the Achilles tendon, possibly due to the limitations of using two-dimensional ultrasound imaging to assess tendon strain. This study used freehand three-dimensional ultrasound (3DUS) to determine whether the free Achilles tendon (calcaneus to soleus) or the gastrocnemius tendon (calcaneus to gastrocnemius) demonstrated tendon fatigue after running exercise. Participants (N=9) underwent 3DUS scans of the Achilles tendon during isometric contractions at four ankle torque levels (passive, and 14, 42 and 70 N m) before and after a 5 km run at a self-selected pace (10-14 km h(-1)). Running had a significant main effect on the length of the free Achilles tendon (P<0.01) with a small increase in length across the torque range. However, the mean lengthening effect was small (<1%) and was not accompanied by a change in free tendon stiffness. There was no significant change in the length of the gastrocnemius tendon or the free tendon cross-sectional area. While the free tendon was shown to lengthen, the lack of change in stiffness suggests the tendon exhibited mechanical creep rather than fatigue. These effects were much smaller than those predicted from in vitro experiments, possibly due to the different loading profile encountered and the ability of the tendon to repair in vivo.

Markers for the identification of tendon-derived stem cells in vitro and tendon stem cells in situ - update and future development.

PubMed

Lui, Pauline Po Yee

2015-06-02

The efficacy of tendon-derived stem cells (TDSCs) for the promotion of tendon and tendon-bone junction repair has been reported in animal studies. Modulation of the tendon stem cell niche in vivo has also been reported to influence tendon structure. There is a need to have specific and reliable markers that can define TDSCs in vitro and tendon stem cells in situ for several reasons: to understand the basic biology of TDSCs and their subpopulations in vitro; to understand the identity, niches and functions of tendon/progenitor stem cells in vivo; to meet the governmental regulatory requirements for quality of TDSCs when translating the exciting preclinical findings into clinical trial/practice; and to develop new treatment strategies for mobilizing endogenous stem/progenitor cells in tendon. TDSCs were reported to express the common mesenchymal stem cell (MSC) markers and some embryonic stem cell (ESC) markers, and there were attempts to use these markers to label tendon stem cells in situ. Are these stem cell markers useful for the identification of TDSCs in vitro and tracking of tendon stem cells in situ? This review aims to discuss the values of the panel of MSC, ESC and tendon-related markers for the identification of TDSCs in vitro. Important factors influencing marker expression by TDSCs are discussed. The usefulness and limitations of the panel of MSC, ESC and tendon-related markers for tracking stem cells in tendon, especially tendon stem cells, in situ are then reviewed. Future research directions are proposed.

Tendon-Holding Capacities of Two Newly Designed Implants for Tendon Repair: An Experimental Study on the Flexor Digitorum Profundus Tendon of Sheep

PubMed Central

Ağır, İsmail; Aytekin, Mahmut Nedim; Başçı, Onur; Çaypınar, Barış; Erol, Bülent

2014-01-01

Background: Two main factors determine the strength of tendon repair; the tensile strength of material and the gripping capacity of a suture configuration. Different repair techniques and suture materials were developed to increase the strength of repairs but none of techniques and suture materials seem to provide enough tensile strength with safety margins for early active mobilization. In order to overcome this problem tendon suturing implants are being developed. We designed two different suturing implants. The aim of this study was to measure tendon-holding capacities of these implants biomechanically and to compare them with frequently used suture techniques Materials and Methods: In this study we used 64 sheep flexor digitorum profundus tendons. Four study groups were formed and each group had 16 tendons. We applied model 1 and model 2 implant to the first 2 groups and Bunnell and locking-loop techniques to the 3rd and 4th groups respectively by using 5 Ticron sutures. Results: In 13 tendons in group 1 and 15 tendons in group 2 and in all tendons in group 3 and 4, implants and sutures pulled out of the tendon in longitudinal axis at the point of maximum load. The mean tensile strengths were the largest in group 1 and smallest in group 3. Conclusion: In conclusion, the new stainless steel tendon suturing implants applied from outside the tendons using steel wires enable a biomechanically stronger repair with less tendon trauma when compared to previously developed tendon repair implants and the traditional suturing techniques. PMID:25067965

Initial experience with visualizing hand and foot tendons by dual-energy computed tomography.

PubMed

Deng, Kai; Sun, Cong; Liu, Cheng; Ma, Rui

2009-01-01

To assess the feasibility of visualizing hand and foot tendons by dual-energy computed tomography (CT). Twenty patients who suffered from hand or feet pains were scanned on dual-source CT (Definition, Forchheim, Germany) with dual-energy mode at tube voltages of 140 and 80 kV and a corresponding ratio of 1:4 between tube currents. The reconstructed images were postprocessed by volume rendering techniques (VRT) and multiplanar reconstruction (MPR). All of the suspected lesions were confirmed by surgery or follow-up studies. Twelve patients (total of 24 hands and feet, respectively) were found to be normal and the other eight patients (total of nine hands and feet, respectively) were found abnormal. Dual-energy techniques are very useful in visualizing tendons of the hands and feet, such as flexor pollicis longus tendon, flexor digitorum superficialis/profundus tendon, Achilles tendon, extensor hallucis longus tendon, and extensor digitorum longus tendon, etc. It can depict the whole shape of the tendons and their fixation points clearly. Peroneus longus tendon in the sole of the foot was not displayed very well. The distal ends of metacarpophalangeal joints with extensor digitoium tendon and extensor pollicis longus tendon were poorly shown. The lesions of tendons such as the circuitry, thickening, and adherence were also shown clearly. Dual-energy CT offers a new method to visualize tendons of the hand and foot. It could clearly display both anatomical structures and pathologic changes of hand and foot tendons.

Quantitative ultrasound method for assessing stress-strain properties and the cross-sectional area of Achilles tendon

NASA Astrophysics Data System (ADS)

Du, Yi-Chun; Chen, Yung-Fu; Li, Chien-Ming; Lin, Chia-Hung; Yang, Chia-En; Wu, Jian-Xing; Chen, Tainsong

2013-12-01

The Achilles tendon is one of the most commonly observed tendons injured with a variety of causes, such as trauma, overuse and degeneration, in the human body. Rupture and tendinosis are relatively common for this strong tendon. Stress-strain properties and shape change are important biomechanical properties of the tendon to assess surgical repair or healing progress. Currently, there are rather limited non-invasive methods available for precisely quantifying the in vivo biomechanical properties of the tendons. The aim of this study was to apply quantitative ultrasound (QUS) methods, including ultrasonic attenuation and speed of sound (SOS), to investigate porcine tendons in different stress-strain conditions. In order to find a reliable method to evaluate the change of tendon shape, ultrasound measurement was also utilized for measuring tendon thickness and compared with the change in tendon cross-sectional area under different stress. A total of 15 porcine tendons of hind trotters were examined. The test results show that the attenuation and broadband ultrasound attenuation decreased and the SOS increased by a smaller magnitude as the uniaxial loading of the stress-strain upon tendons increased. Furthermore, the tendon thickness measured with the ultrasound method was significantly correlated with tendon cross-sectional area (Pearson coefficient = 0.86). These results also indicate that attenuation of QUS and ultrasonic thickness measurement are reliable and potential parameters for assessing biomechanical properties of tendons. Further investigations are needed to warrant the application of the proposed method in a clinical setting.

Comparison of Autograft and Allograft with Surface Modification for Flexor Tendon Reconstruction: A Canine in Vivo Model.

PubMed

Wei, Zhuang; Reisdorf, Ramona L; Thoreson, Andrew R; Jay, Gregory D; Moran, Steven L; An, Kai-Nan; Amadio, Peter C; Zhao, Chunfeng

2018-04-04

Flexor tendon injury is common, and tendon reconstruction is indicated clinically if the primary repair fails or cannot be performed immediately after tendon injury. The purpose of the current study was to compare clinically standard extrasynovial autologous graft (EAG) tendon and intrasynovial allogeneic graft (IAG) that had both undergone biolubricant surface modification in a canine in vivo model. Twenty-four flexor digitorum profundus (FDP) tendons from the second and fifth digits of 12 dogs were used for this study. In the first phase, a model of failed FDP tendon repair was created. After 6 weeks, the ruptured FDP tendons with a scarred digit were reconstructed with the use of either EAG or IAG tendons treated with carbodiimide-derivatized hyaluronic acid and lubricin. At 12 weeks after tendon reconstruction, the digits were harvested for functional, biomechanical, and histologic evaluations. The tendon failure model was a clinically relevant and reproducible model for tendon reconstruction. The IAG group demonstrated improved digit function with decreased adhesion formation, lower digit work of flexion, and improved graft gliding ability compared with the EAG group. However, the IAG group had decreased healing at the distal tendon-bone junction. Our histologic findings verified the biomechanical evaluations and, further, showed that cellular repopulation of allograft at 12 weeks after reconstruction is still challenging. FDP tendon reconstruction using IAG with surface modification has some beneficial effects for reducing adhesions but demonstrated inferior healing at the distal tendon-bone junction compared with EAG. These mixed results indicate that vitalization and turnover acceleration are crucial to reducing failure of reconstruction with allograft. Flexor tendon reconstruction is a common surgical procedure. However, postoperative adhesion formation may lead to unsatisfactory clinical outcomes. In this study, we developed a potential flexor tendon allograft using chemical and tissue-engineering approaches. This technology could improve function following tendon reconstruction.

Patellar tendon re-rupture on the opposite end of the previous site of surgical repair

PubMed Central

KOH, Bryan Thean Howe; SAYAMPANATHAN, Andrew A; LEE, Keng Thiam

2017-01-01

We describe a rare case of a patellar tendon “re-rupture” at the opposite end of a previous proximal tendon repair. A 32-year-old male with a history of surgically repaired right proximal patellar tendon rupture presented with an acute non-traumatic right knee pain and instability during sports. Magnetic resonance imaging confirmed a complete rupture of his distal patellar tendon at the tibial tuberosity. The patellar tendon was repaired using two 5.5 mm BioCorkscrews (Arthrex) inserted into the tibial tuberosity; the tendon was stitched with the No. 2 fiberwires using Krackow technique. As the patellar tendon was degenerative, the repair was augmented with a semitendinosus tendon harvested using an open tendon stripper, leaving the distal attachment intact. At 2.6 years followup he had mild anterior knee pain, range of motion 0-130° and was able to squat. MRI scan done at followup revealed good healing of repaired patellar tendon. PMID:28566788

A Biomechanical Comparison of Allograft Tendons for Ligament Reconstruction.

PubMed

Palmer, Jeremiah E; Russell, Joseph P; Grieshober, Jason; Iacangelo, Abigail; Ellison, Benjamin A; Lease, T Dylan; Kim, Hyunchul; Henn, R Frank; Hsieh, Adam H

2017-03-01

Allograft tendons are frequently used for ligament reconstruction about the knee, but they entail availability and cost challenges. The identification of other tissues that demonstrate equivalent performance to preferred tendons would improve limitations. Hypothesis/Purpose: We compared the biomechanical properties of 4 soft tissue allograft tendons: tibialis anterior (TA), tibialis posterior (TP), peroneus longus (PL), and semitendinosus (ST). We hypothesized that allograft properties would be similar when standardized by the looped diameter. Controlled laboratory study. This study consisted of 2 arms evaluating large and small looped-diameter grafts: experiment A consisted of TA, TP, and PL tendons (n = 47 each) with larger looped diameters of 9.0 to 9.5 mm, and experiment B consisted of TA, TP, PL, and ST tendons (n = 53 each) with smaller looped diameters of 7.0 to 7.5 mm. Each specimen underwent mechanical testing to measure the modulus of elasticity (E), ultimate tensile force (UTF), maximal elongation at failure, ultimate tensile stress (UTS), and ultimate tensile strain (UTε). Experiment A: No significant differences were noted among tendons for UTF, maximal elongation at failure, and UTϵ. UTS was significantly higher for the PL (54 MPa) compared with the TA (44 MPa) and TP (43 MPa) tendons. E was significantly higher for the PL (501 MPa) compared with the TP (416 MPa) tendons. Equivalence testing showed that the TP and PL tendon properties were equivalent or superior to those of the TA tendons for all outcomes. Experiment B: All groups exhibited a similar E. UTF was again highest in the PL tendons (2294 N) but was significantly different from only the ST tendons (1915 N). UTϵ was significantly higher for the ST (0.22) compared with the TA (0.19) and TP (0.19) tendons. Equivalence testing showed that the TA, TP, and PL tendon properties were equivalent or superior to those of the ST tendons. Compared with TA tendons, TP and PL tendons of a given looped diameter exhibited noninferior initial biomechanical strength and stiffness characteristics. ST tendons were mostly similar to TA tendons but exhibited a significantly higher elongation/UTϵ and smaller cross-sectional area. For smaller looped-diameter grafts, all tissues were noninferior to ST tendons. In contrast to previous findings, PL tendons proved to be equally strong. The results of this study should encourage surgeons to use these soft tissue allografts interchangeably, which is important as the number of ligament reconstructions performed with allografts continues to rise.

Histological study of the influence of plasma rich in growth factors (PRGF) on the healing of divided Achilles tendons in sheep.

PubMed

Fernández-Sarmiento, J Andrés; Domínguez, Juan M; Granados, María M; Morgaz, Juan; Navarrete, Rocío; Carrillo, José M; Gómez-Villamandos, Rafael J; Muñoz-Rascón, Pilar; Martín de Las Mulas, Juana; Millán, Yolanda; García-Balletbó, Montserrat; Cugat, Ramón

2013-02-06

The use of plasma rich in growth factors (PRGF) has been proposed to improve the healing of Achilles tendon injuries, but there is debate about the effectiveness of this therapy. The objective of the present study was to evaluate the histological effects of PRGF, which is a type of leukocyte-poor platelet-rich plasma, on tendon healing. The Achilles tendons of twenty-eight sheep were divided surgically. The animals were randomly divided into four groups of seven animals each. The repaired tendons in two groups received an infiltration of PRGF intraoperatively and every week for the following three weeks under ultrasound guidance. The tendons in the other two groups received injections with saline solution. The animals in one PRGF group and one saline solution group were killed at four weeks, and the animals in the remaining two groups were killed at eight weeks. The Achilles tendons were examined histologically, and the morphometry of fibroblast nuclei was calculated. The fibroblast nuclei of the PRGF-treated tendons were more elongated and more parallel to the tendon axis than the fibroblast nuclei of the tendons in the saline solution group at eight weeks. PRGF-treated tendons showed more packed and better oriented collagen bundles at both four and eight weeks. In addition to increased maturation of the collagen structure, fibroblast density was significantly lower in PRGF-infiltrated tendons. PRGF-treated tendons exhibited faster vascular regression than tendons in the control groups, as demonstrated by a lower vascular density at eight weeks. PRGF was associated with histological changes consistent with an accelerated early healing process in repaired Achilles tendons in sheep after experimental surgical disruption. PRGF-treated tendons showed improvements in the morphometric features of fibroblast nuclei, suggesting a more advanced stage of healing. At eight weeks, histological examination revealed more mature organization of collagen bundles, lower vascular densities, and decreased fibroblast densities in PRGF-treated tendons than in tendons infiltrated with saline solution. These findings were consistent with a more advanced stage of the healing process. Based on the findings in this animal model, PRGF infiltration may improve the early healing process of surgically repaired Achilles tendons.

A review on animal models and treatments for the reconstruction of Achilles and flexor tendons.

PubMed

Bottagisio, Marta; Lovati, Arianna B

2017-03-01

Tendon is a connective tissue mainly composed of collagen fibers with peculiar mechanical properties essential to functional movements. The increasing incidence of tendon traumatic injuries and ruptures-associated or not with the loss of tissue-falls on the growing interest in the field of tissue engineering and regenerative medicine. The use of animal models is mandatory to deepen the knowledge of the tendon healing response to severe damages or acute transections. Thus, the selection of preclinical models is crucial to ensure a successful translation of effective and safe innovative treatments to the clinical practice. The current review is focused on animal models of tendon ruptures and lacerations or defective injuries with large tissue loss that require surgical approaches or grafting procedures. Data published between 2000 and 2016 were examined. The analyzed articles were compiled from Pub Med-NCBI using search terms, including animal model(s) AND tendon augmentation OR tendon substitute(s) OR tendon substitution OR tendon replacement OR tendon graft(s) OR tendon defect(s) OR tendon rupture(s). This article presents the existing preclinical models - considering their advantages and disadvantages-in which translational progresses have been made by using bioactive sutures or tissue engineering that combines biomaterials with cells and growth factors to efficiently treat transections or large defects of Achilles and flexor tendons.

Rescue plan for Achilles: Therapeutics steering the fate and functions of stem cells in tendon wound healing.

PubMed

Schneider, Magdalena; Angele, Peter; Järvinen, Tero A H; Docheva, Denitsa

2017-12-24

Due to the increasing age of our society and a rise in engagement of young people in extreme and/or competitive sports, both tendinopathies and tendon ruptures present a clinical and financial challenge. Tendon has limited natural healing capacity and often responds poorly to treatments, hence it requires prolonged rehabilitation in most cases. Till today, none of the therapeutic options has provided successful long-term solutions, meaning that repaired tendons do not recover their complete strength and functionality. Our understanding of tendon biology and healing increases only slowly and the development of new treatment options is insufficient. In this review, following discussion on tendon structure, healing and the clinical relevance of tendon injury, we aim to elucidate the role of stem cells in tendon healing and discuss new possibilities to enhance stem cell treatment of injured tendon. To date, studies mainly apply stem cells, often in combination with scaffolds or growth factors, to surgically created tendon defects. Deeper understanding of how stem cells and vasculature in the healing tendon react to growth factors, common drugs used to treat injured tendons and promising cellular boosters could help to develop new and more efficient ways to manage tendon injuries. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

Effects of high loading by eccentric triceps surae training on Achilles tendon properties in humans.

PubMed

Geremia, Jeam Marcel; Baroni, Bruno Manfredini; Bobbert, Maarten Frank; Bini, Rodrigo Rico; Lanferdini, Fabio Juner; Vaz, Marco Aurélio

2018-06-01

To document the magnitude and time course of human Achilles tendon adaptations (i.e. changes in tendon morphological and mechanical properties) during a 12-week high-load plantar flexion training program. Ultrasound was used to determine Achilles tendon cross-sectional area (CSA), length and elongation as a function of plantar flexion torque during voluntary plantar flexion. Tendon force-elongation and stress-strain relationships were determined before the start of training (pre-training) and after 4 (post-4), 8 (post-8) and 12 (post-12) training weeks. At the end of the training program, maximum isometric force had increased by 49% and tendon CSA by 17%, but tendon length, maximal tendon elongation and maximal strain were unchanged. Hence, tendon stiffness had increased by 82%, and so had Young's modulus, by 86%. Significant changes were first detected at post-4 in stiffness (51% increase) and Young's modulus (87% increase), and at post-8 in CSA (15% increase). Achilles tendon material properties already improved after 4 weeks of high-load training: stiffness increased while CSA remained unchanged. Tendon hypertrophy (increased CSA) was observed after 8 training weeks and contributed to a further increase in Achilles tendon stiffness, but tendon stiffness increases were mostly caused by adaptations in tissue properties.

Grasp Assist Device with Shared Tendon Actuator Assembly

NASA Technical Reports Server (NTRS)

Ihrke, Chris A. (Inventor); Bergelin, Bryan J. (Inventor); Bridgwater, Lyndon (Inventor)

2015-01-01

A grasp assist device includes a glove with first and second tendon-driven fingers, a tendon, and a sleeve with a shared tendon actuator assembly. Tendon ends are connected to the respective first and second fingers. The actuator assembly includes a drive assembly having a drive axis and a tendon hook. The tendon hook, which defines an arcuate surface slot, is linearly translatable along the drive axis via the drive assembly, e.g., a servo motor thereof. The flexible tendon is routed through the surface slot such that the surface slot divides the flexible tendon into two portions each terminating in a respective one of the first and second ends. The drive assembly may include a ball screw and nut. An end cap of the actuator assembly may define two channels through which the respective tendon portions pass. The servo motor may be positioned off-axis with respect to the drive axis.

Multiple tendon ruptures of unknown etiology.

PubMed

Axibal, Derek P; Anderson, John G

2013-10-01

Tendon ruptures are common findings in foot and ankle practice. The etiology of tendon ruptures tends to be multifactorial-usually due to a combination of trauma, effects of systemic diseases, adverse effects of medications, and obesity. We present an unusual case of right Achilles tendinitis, left Achilles tendon rupture, bilateral peroneus longus tendon rupture, and left peroneus brevis tendon rupture of unknown etiology. This case report highlights the need for research for other possible, lesser known etiologies of tendon pathology. Therapeutic, Level IV, Case Study.

The Effects of Bio-Lubricating Molecules on Flexor Tendon Reconstruction in A Canine Allograft Model In Vivo

PubMed Central

Zhao, Chunfeng; Wei, Zhuang; Kirk, Ramona L.; Thoreson, Andrew R.; Jay, Gregory D.; Moran, Steven L.; An, Kai-Nan; Amadio, Peter C.

2014-01-01

Background Using allograft is an attractive alternative for flexor tendon reconstruction because of the lack of donor morbidity, and better matching to the intrasynovial environment. The purpose of this study was to use biolubricant molecules to modify the graft surface to decrease adhesions and improve digit function. Methods 28 flexor digitorum profundus (FDP) tendons from the 2nd and 5th digits of 14 dogs were first lacerated and repaired to create a model with repair failure and scar digit for tendon reconstruction. Six weeks after the initial surgery, the tendons were reconstructed with FDP allograft tendons obtained from canine cadavers. One graft tendon in each dog was treated with saline as a control and the other was treated with gelatin, carbodiimide derivatized, hyaluronic acid and lubricin (cd-HA-Lubricin). Six weeks postoperatively, digit function, graft mechanics, and biology were analyzed. Results Allograft tendons treated with cd-HA-Lubricin had decreased adhesions at the proximal tendon/graft repair and within flexor sheath, improved digit function, and increased graft gliding ability. The treatment also reduced the strength at the distal tendon to bone repair, but the distal attachment rupture rate was similar for both graft types. Histology showed that viable cells migrated to the allograft, but these were limited to the tendon surface. Conclusion cd-HA-Lubricin treatment of tendon allograft improves digit functional outcomes after flexor tendon reconstruction. However, delayed bone-tendon healing should be a caution. Furthermore, the cell infiltration into the allograft tendons substance should be a target for future studies, to shorten the allograft self-regeneration period. PMID:24445876

Biomechanical and histological effects of augmented soft tissue mobilization therapy on achilles tendinopathy in a rabbit model.

PubMed

Imai, Kan; Ikoma, Kazuya; Chen, Qingshan; Zhao, Chunfeng; An, Kai-Nan; Gay, Ralph E

2015-02-01

Augmented soft tissue mobilization (ASTM) has been used to treat Achilles tendinopathy and is thought to promote collagen fiber realignment and hasten tendon regeneration. The objective of this study was to evaluate the biomechanical and histological effects of ASTM therapy on rabbit Achilles tendons after enzymatically induced injury. This study was a non-human bench controlled research study using a rabbit model. Both Achilles tendons of 12 rabbits were injected with collagenase to produce tendon injury simulating Achilles tendinopathy. One side was then randomly allocated to receive ASTM, while the other received no treatment (control). ASTM was performed on the Achilles tendon on postoperative days 21, 24, 28, 31, 35, and 38. Tendons were harvested 10 days after treatment and examined with dynamic viscoelasticity and light microscopy. Cross-sectional area in the treated tendons was significantly greater than in controls. Storage modulus tended to be lower in the treated tendons but elasticity was not significantly increased. Loss modulus was significantly lower in the treated tendons. There was no significant difference found in tangent delta (loss modulus/storage modulus). Microscopy of control tendons showed that the tendon fibers were wavy and type III collagen was well stained. The tendon fibers of the augmented soft tissue mobilization treated tendons were not wavy and type III collagen was not prevalent. Biomechanical and histological findings showed that the Achilles tendons treated with ASTM had better recovery of biomechanical function than did control tendons. Copyright © 2015 National University of Health Sciences. Published by Elsevier Inc. All rights reserved.

Augmentation of Distal Biceps Repair With an Acellular Dermal Graft Restores Native Biomechanical Properties in a Tendon-Deficient Model.

PubMed

Conroy, Christine; Sethi, Paul; Macken, Craig; Wei, David; Kowalsky, Marc; Mirzayan, Raffy; Pauzenberger, Leo; Dyrna, Felix; Obopilwe, Elifho; Mazzocca, Augustus D

2017-07-01

The majority of distal biceps tendon injuries can be repaired in a single procedure. In contrast, complete chronic tears with severe tendon substance deficiency and retraction often require tendon graft augmentation. In cases with extensive partial tears of the distal biceps, a human dermal allograft may be used as an alternative to restore tendon thickness and biomechanical integrity. Dermal graft augmentation will improve load to failure compared with nonaugmented repair in a tendon-deficient model. Controlled laboratory study. Thirty-six matched specimens were organized into 1 of 4 groups: native tendon, native tendon with dermal graft augmentation, tendon with an attritional defect, and tendon with an attritional defect repaired with a graft. To mimic a chronic attritional biceps lesion, a defect was created by a complete tear, leaving 30% of the tendon's width intact. The repair technique in all groups consisted of cortical button and interference screw fixation. All specimens underwent cyclical loading for 3000 cycles and were then tested to failure; gap formation and peak load at failure were documented. The mean (±SD) load to failure (320.9 ± 49.1 N vs 348.8 ± 77.6 N, respectively; P = .38) and gap formation (displacement) (1.8 ± 1.4 mm vs 1.6 ± 1.1 mm, respectively; P = .38) did not differ between the native tendon groups with and without graft augmentation. In the tendon-deficient model, the mean load to failure was significantly improved with graft augmentation compared with no graft augmentation (282.1 ± 83.8 N vs 199.7 ± 45.5 N, respectively; P = .04), while the mean gap formation was significantly reduced (1.2 ± 1.0 mm vs 2.7 ± 1.4 mm, respectively; P = .04). The mean load to failure of the deficient tendon with graft augmentation (282.1 N) compared with the native tendon (348.8 N) was not significantly different ( P = .12). This indicates that the native tendon did not perform differently from the grafted deficient tendon. In a tendon-deficient, complete distal biceps rupture model, acellular dermal allograft augmentation restored the native tendon's biomechanical properties at time zero. The grafted tissue-deficient model demonstrated no significant differences in the load to failure and gap formation compared with the native tendon. As expected, dermal augmentation of attritional tendon repair increased the load to failure and stiffness as well as decreased displacement compared with the ungrafted tissue-deficient model. Tendons with their native width showed no statistical difference or negative biomechanical consequences of dermal augmentation. Dermal augmentation of the distal biceps is a biomechanically feasible option for patients with an attritionally thinned-out tendon.

US appearance of partial-thickness supraspinatus tendon tears: Application of the string theory. Pictorial essay.

PubMed

Guerini, H; Fermand, M; Godefroy, D; Feydy, A; Chevrot, A; Morvan, G; Gault, N; Drapé, J L

2012-02-01

The supraspinatus tendon is composed of 5 different layers consisting of intertwining bundles. On a front portion of the tendon, the layers become coated bundles which insert on the trochanter. At the insertion, the superficial or bursal surface of the tendon corresponding to the tendon fibers in contact with the subacromial bursa can be distinguished from the deep surface corresponding to the fibers in contact with the glenohumeral joint. A tendon tear may involve partial or total disruption of the tendon fibers and is called full-thickness tear if it affects the entire tendon, and partial-thickness tear if it involves only part of the tendon. Partial-thickness tears of the supraspinatus tendon include lesions of the superficial, deep and central surface or tendon delamination.A contrast enhanced examination requires injection of contrast agent into the joint (arthrography followed by computed tomography (CT) or magnetic resonance imaging (MRI)) to study the deep surface, and injection into the subacromial bursa (bursography followed by CT) to study the superficial surface. MRI and ultrasound (US) examination allow the study of these different tendon layers without the use of contrast agent (which is not possible at CT).

Human tendon behaviour and adaptation, in vivo

PubMed Central

Magnusson, S Peter; Narici, Marco V; Maganaris, Constantinos N; Kjaer, Michael

2008-01-01

Tendon properties contribute to the complex interaction of the central nervous system, muscle–tendon unit and bony structures to produce joint movement. Until recently limited information on human tendon behaviour in vivo was available; however, novel methodological advancements have enabled new insights to be gained in this area. The present review summarizes the progress made with respect to human tendon and aponeurosis function in vivo, and how tendons adapt to ageing, loading and unloading conditions. During low tensile loading or with passive lengthening not only the muscle is elongated, but also the tendon undergoes significant length changes, which may have implications for reflex responses. During active loading, the length change of the tendon far exceeds that of the aponeurosis, indicating that the aponeurosis may more effectively transfer force onto the tendon, which lengthens and stores elastic energy subsequently released during unloading, in a spring-like manner. In fact, data recently obtained in vivo confirm that, during walking, the human Achilles tendon provides elastic strain energy that can decrease the energy cost of locomotion. Also, new experimental evidence shows that, contrary to earlier beliefs, the metabolic activity in human tendon is remarkably high and this affords the tendon the ability to adapt to changing demands. With ageing and disuse there is a reduction in tendon stiffness, which can be mitigated with resistance exercises. Such adaptations seem advantageous for maintaining movement rapidity, reducing tendon stress and risk of injury, and possibly, for enabling muscles to operate closer to the optimum region of the length–tension relationship. PMID:17855761

Shear load transfer in high and low stress tendons.

PubMed

Kondratko-Mittnacht, Jaclyn; Duenwald-Kuehl, Sarah; Lakes, Roderic; Vanderby, Ray

2015-05-01

Tendon is an integral part of joint movement and stability, as it functions to transmit load from muscle to bone. It has an anisotropic, fibrous hierarchical structure that is generally loaded in the direction of its fibers/fascicles. Internal load distributions are altered when joint motion rotates an insertion site or when local damage disrupts fibers/fascicles, potentially causing inter-fiber (or inter-fascicular) shear. Tendons with different microstructures (helical versus linear) may redistribute loads differently. This study explored how shear redistributes axial loads in rat tail tendon (low stress tendons with linear microstructure) and porcine flexor tendon (high stress with helical microstructure) by creating lacerations on opposite sides of the tendon, ranging from about 20% to 60% of the tendon width, to create various magnitudes of shear. Differences in fascicular orientation were quantified using polarized light microscopy. Unexpectedly, both tendon types maintained about 20% of pre-laceration stress values after overlapping cuts of 60% of tendon width (no intact fibers end to end) suggesting that shear stress transfer can contribute more to overall tendon strength and stiffness than previously reported. All structural parameters for both tendon types decreased linearly with increasing laceration depth. The tail tendon had a more rapid decline in post-laceration elastic stress and modulus parameters as well as a more linear and less tightly packed fascicular structure, suggesting that positional tendons may be less well suited to redistribute loads via a shear mechanism. Copyright © 2015 Elsevier Ltd. All rights reserved.

Shear Load Transfer in High and Low Stress Tendons

PubMed Central

Kondratko-Mittnacht, Jaclyn; Duenwald-Kuehl, Sarah; Lakes, Roderic; Vanderby, Ray

2016-01-01

Background Tendon is an integral part of joint movement and stability, as it functions to transmit load from muscle to bone. It has an anisotropic, fibrous hierarchical structure that is generally loaded in the direction of its fibers/fascicles. Internal load distributions are altered when joint motion rotates an insertion site or when local damage disrupts fibers/fascicles, potentially causing inter-fiber (or inter-fascicular) shear. Tendons with different microstructure (helical versus linear) may redistribute loads differently. Method of Approach This study explored how shear redistributes axial loads in rat tail tendon (low stress tendons with linear microstructure) and porcine flexor tendon (high stress with helical microstructure) by creating lacerations on opposite sides of the tendon, ranging from about 20-60% of the tendon width, to create various magnitudes of shear. Differences in fascicular orientation were quantified using polarized light microscopy. Results and Conclusions Unexpectedly, both tendon types maintained about 20% of pre-laceration stress values after overlapping cuts of 60% of tendon width (no intact fibers end to end) suggesting that shear stress transfer can contribute more to overall tendon strength and stiffness than previously reported. All structural parameters for both tendon types decreased linearly with increasing laceration depth. The tail tendon had a more rapid decline in post-laceration elastic stress and modulus parameters as well as a more linear and less tightly packed fascicular structure, suggesting that positional tendons may be less well suited to redistribute loads via a shear mechanism. PMID:25700261

Lubricin Surface Modification Improves Tendon Gliding After Tendon Repair in a Canine Model in Vitro

PubMed Central

Taguchi, Manabu; Sun, Yu-Long; Zhao, Chunfeng; Zobitz, Mark E.; Cha, Chung-Ja; Jay, Gregory D.; An, Kai-Nan; Amadio, Peter C.

2011-01-01

This study investigated the effects of lubricin on the gliding of repaired flexor digitorum profundus (FDP) tendons in vitro. Canine FDP tendons were completely lacerated, repaired with a modified Pennington technique, and treated with one of the following solutions: saline, carbodiimide derivatized gelatin/hyaluronic acid (cd-HA-gelatin), carbodiimide derivatized gelatin to which lubricin was added in a second step (cd-gelatin + lubricin), or carbodiimide derivatized gelatin/HA + lubricin (cd-HA-gelatin + lubricin). After treatment, gliding resistance was measured up to 1,000 cycles of simulated flexion/extension motion. The increase in average and peak gliding resistance in cd-HA-gelatin, cd-gelatin + lubricin, and cd-HA-gelatin + lubricin tendons was less than the control tendons after 1,000 cycles (p < 0.05). The increase in average gliding resistance of cd-HA-gelatin + lubricin treated tendons was also less than that of the cd-HA-gelatin treated tendons (p < 0.05). The surfaces of the repaired tendons and associated pulleys were assessed qualitatively with scanning electron microscopy and appeared smooth after 1,000 cycles of tendon motion for the cd-HA-gelatin, cd-gelatin + lubricin, and cd-HA-gelatin + lubricin treated tendons, while that of the saline control appeared roughened. These results suggest that tendon surface modification can improve tendon gliding ability, with a trend suggesting that lubricin fixed on the repaired tendon may provide additional improvement over that provided by HA and gelatin alone. PMID:18683890

Pleiotropic roles of the matricellular protein Sparc in tendon maturation and ageing

PubMed Central

Gehwolf, Renate; Wagner, Andrea; Lehner, Christine; Bradshaw, Amy D.; Scharler, Cornelia; Niestrawska, Justyna A.; Holzapfel, Gerhard A.; Bauer, Hans-Christian; Tempfer, Herbert; Traweger, Andreas

2016-01-01

Acute and chronic tendinopathies remain clinically challenging and tendons are predisposed to degeneration or injury with age. Despite the high prevalence of tendon disease in the elderly, our current understanding of the mechanisms underlying the age-dependent deterioration of tendon function remains very limited. Here, we show that Secreted protein acidic and rich in cysteine (Sparc) expression significantly decreases in healthy-aged mouse Achilles tendons. Loss of Sparc results in tendon collagen fibrillogenesis defects and Sparc−/− tendons are less able to withstand force in comparison with their respective wild type counterparts. On the cellular level, Sparc-null and healthy-aged tendon-derived cells exhibited a more contracted phenotype and an altered actin cytoskeleton. Additionally, an elevated expression of the adipogenic marker genes PPARγ and Cebpα with a concomitant increase in lipid deposits in aged and Sparc−/− tendons was observed. In summary, we propose that Sparc levels in tendons are critical for proper collagen fibril maturation and its age-related decrease, together with a change in ECM properties favors lipid accretion in tendons. PMID:27586416

Phenytoin accelerates tendon healing in a rat model of Achilles tendon rupture.

PubMed

Hajipour, B; Navali, A M; Mohammad, S Ali; Mousavi, G; Akbari, M Gahvechi; Miyandoab, T Maleki; Roshangar, L; Saleh, B Mohammadi; Kermani, T Asvadi; Laleh, F Moutab; Ghabili, M

2016-01-01

Tendons are vulnerable to various types of acute or chronic injures. Different methods have been investigated to achieve better healing. Phenytoin is a drug which could stimulate fibroblasts to produce collagen. This experimental study was performed to assess the effect of phenytoin on tendon healing in a rat model of tendon rupture. Thirty healthy rats were divided into 3 groups, 1) Sham group; 2) Tendon rupture; 3) Tendon rupture+phenytoin (100 mg/kg intraperitoneally) for 21 days. On 21st day after tendon injury, the rats were anesthetized and tendon tissue was sampled for studying by light and electron microscopy. Qualitative and quantitative microscopic comparisons of the repair tissues of both groups were made on the 21st day. The results obtained from light and electron microscopy studies showed that tendon tissue healing was significantly better in phenytoin group compared to the control group (p < 0.05). Systemic administration of phenytoin may have a positive effect on tendon healing by increasing fibroblast quantity, fibrillar collagen synthesis, vascularity, and suppressing inflammation (Tab. 2, Ref. 25).

Quadriceps tendon autograft for arthroscopic knee ligament reconstruction: use it now, use it often.

PubMed

Sheean, Andrew J; Musahl, Volker; Slone, Harris S; Xerogeanes, John W; Milinkovic, Danko; Fink, Christian; Hoser, Christian

2018-04-28

Traditional bone-patellar tendon-bone and hamstring tendon ACL grafts are not without limitations. A growing body of anatomic, biomechanical and clinical data has demonstrated the utility of quadriceps tendon autograft in arthroscopic knee ligament reconstruction. The quadriceps tendon autograft provides a robust volume of tissue that can be reliably harvested, mitigating the likelihood of variably sized grafts and obviating the necessity of allograft augmentation. Modern, minimally invasive harvest techniques offer the advantages of low rates of donor site morbidity and residual extensor mechanism strength deficits. New data suggest that quadriceps tendon autograft may possess superior biomechanical characteristics when compared with bone-patella tendon-bone (BPTB) autograft. However, there have been very few direct, prospective comparisons between the clinical outcomes associated with quadriceps tendon autograft and other autograft options (eg, hamstring tendon and bone-patellar tendon-bone). Nevertheless, quadriceps tendon autograft should be one of the primary options in any knee surgeon's armamentarium. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Magnetic resonance imaging-controlled results of the pectoralis major tendon transfer for irreparable anterosuperior rotator cuff tears performed with standard and modified fixation techniques.

PubMed

Lederer, Stefan; Auffarth, Alexander; Bogner, Robert; Tauber, Mark; Mayer, Michael; Karpik, Stefanie; Matis, Nicholas; Resch, Herbert

2011-10-01

Irreparable ruptures of the subscapularis tendon lead to impaired function of the shoulder joint. In such cases, transfer of the pectoralis major tendon has led to encouraging results. The procedure fails periodically, typically associated with insufficient in-growth of the transferred tissue. We hypothesized that tendon harvest with chips of cancellous bone would improve the tendon-bone interface. Of 62 consecutive pectoralis tendon transfers, 54 shoulders were followed-up at an average of 35 months. In all shoulders, the transferred tendon was rerouted behind the conjoint tendon and fixed by transosseous sutures. In 29 shoulders, the tendon was harvested with a cuff of cancellous bone. In 25 shoulders, the conventional technique with sharp detachment of the tendon was used. Apart from detailed clinical examination of all shoulders, a magnetic resonance image (MRI) was available in 52 shoulders. The overall Constant score had improved from an average of 38.8 points preoperatively to 63.4 points at follow-up. Shoulders treated with the new fixation technique scored 64.4 compared with 62.2 for the conventional fixations. The MRI showed intact tendons and muscles in 80.8% of shoulders. In 7 shoulders (13.5%), the transferred tendon was ruptured. Two of these were treated with the new fixation technique. Mean patient satisfaction score was 8.2 points. A secure method of fixation that avoids secondary ruptures despite insufficiency of the transferred tendon is of great importance. Also the rerouting of the transferred tendon under the conjoined tendon is essential to imitate the natural force vector and the function of an intact subscapularis tendon. Patients in this investigation were also monitored by MRI to verify the integrity of the transferred tendon. As a salvage procedure, the pectoralis major tendon transfer provides good results in most cases. Sufficient in-growth of the transferred tissue is essential for the success of the procedure. This seems to be facilitated by both methods. Copyright © 2011 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved.

Non-linear finite element model to assess the effect of tendon forces on the foot-ankle complex.

PubMed

Morales-Orcajo, Enrique; Souza, Thales R; Bayod, Javier; Barbosa de Las Casas, Estevam

2017-11-01

A three-dimensional foot finite element model with actual geometry and non-linear behavior of tendons is presented. The model is intended for analysis of the lower limb tendon forces effect in the inner foot structure. The geometry of the model was obtained from computational tomographies and magnetic resonance images. Tendon tissue was characterized with the first order Ogden material model based on experimental data from human foot tendons. Kinetic data was employed to set the load conditions. After model validation, a force sensitivity study of the five major foot extrinsic tendons was conducted to evaluate the function of each tendon. A synergic work of the inversion-eversion tendons was predicted. Pulling from a peroneus or tibialis tendon stressed the antagonist tendons while reducing the stress in the agonist. Similar paired action was predicted for the Achilles tendon with the tibialis anterior. This behavior explains the complex control motion performed by the foot. Furthermore, the stress state at the plantar fascia, the talocrural joint cartilage, the plantar soft tissue and the tendons were estimated in the early and late midstance phase of walking. These estimations will help in the understanding of the functional role of the extrinsic muscle-tendon-units in foot pronation-supination. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

Changes in Achilles tendon mechanical properties following eccentric heel drop exercise are specific to the free tendon.

PubMed

Obst, S J; Newsham-West, R; Barrett, R S

2016-04-01

Mechanical loading of the Achilles tendon during isolated eccentric contractions could induce immediate and region-dependent changes in mechanical properties. Three-dimensional ultrasound was used to examine the immediate effect of isolated eccentric exercise on the mechanical properties of the distal (free tendon) and proximal (gastrocnemii) regions of the Achilles tendon. Participants (n = 14) underwent two testing sessions in which tendon measurements were made at rest and during a 30% and 70% isometric plantar flexion contractions immediately before and after either: (a) 3 × 15 eccentric heel drops or (b) 10-min rest. There was a significant time-by-session interaction for free tendon length and strain for all loading conditions (P < 0.05). Pairwise comparisons revealed a significant increase in free tendon length and strain at all contraction intensities after eccentric exercise (P < 0.05). There was no significant time-by-session interaction for the gastrocnemii (medial or lateral) aponeurosis or tendon for any of the measured parameters. Immediate changes in Achilles tendon mechanical properties were specific to the free tendon and consistent with changes due to mechanical creep. These findings suggest that the mechanical properties of the free tendon may be more vulnerable to change with exercise compared with the gastrocnemii aponeurosis or tendon. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Deficits in heel-rise height and achilles tendon elongation occur in patients recovering from an Achilles tendon rupture.

PubMed

Silbernagel, Karin Grävare; Steele, Robert; Manal, Kurt

2012-07-01

Whether an Achilles tendon rupture is treated surgically or not, complications such as muscle weakness, decrease in heel-rise height, and gait abnormalities persist after injury. The purpose of this study was to evaluate if side-to-side differences in maximal heel-rise height can be explained by differences in Achilles tendon length. Case series; level of evidence, 4. Eight patients (mean [SD] age of 46 [13] years) with acute Achilles tendon rupture and 10 healthy subjects (mean [SD] age of 28 [8] years) were included in the study. Heel-rise height, Achilles tendon length, and patient-reported outcome were measured 3, 6, and 12 months after injury. Achilles tendon length was evaluated using motion analysis and ultrasound imaging. The Achilles tendon length test-retest reliability (intraclass correlation coefficient = 0.97) was excellent. For the healthy subjects, there were no side-to-side differences in tendon length and heel-rise height. Patients with Achilles tendon ruptures had significant differences between the injured and uninjured side for both tendon length (mean [SD] difference, 2.6-3.1 [1.2-1.4] cm, P = .017-.028) and heel-rise height (mean [SD] difference, -4.1 to -6.1 [1.7-1.8] cm, P = .012-.028). There were significant negative correlations (r = -0.943, P = .002, and r = -0.738, P = .037) between the side-to-side difference in heel-rise height and Achilles tendon length at the 6- and 12-month evaluations, respectively. The side-to-side difference found in maximal heel-rise height can be explained by a difference in Achilles tendon length in patients recovering from an Achilles tendon rupture. Minimizing tendon elongation appears to be an important treatment goal when aiming for full return of function.

Reconstruction of chronic achilles tendon rupture with the use of interposed tissue between the stumps.

PubMed

Yasuda, Toshito; Kinoshita, Mitsuo; Okuda, Ryuzo

2007-04-01

The gap between the tendon stumps in chronic Achilles tendon rupture has reportedly been filled with interposed scar tissue. In the authors' clinical experience, this interposed tissue is often thick and resists tension, so they considered it was possible to use the interposed tissue for reconstruction of Achilles tendon rupture. Scar tissue interposed between the tendon stumps has the capacity to form tendon-like repair tissue in patients with chronic Achilles tendon rupture. Case series; Level of evidence, 4. Six patients with chronic rupture of the Achilles tendon underwent tendon reconstruction with the use of interposed tissue between the stumps. The average time from the primary injury to surgery was 22 weeks (range, 9 to 30 weeks). Preoperative magnetic resonance imaging (MRI), histology of the interposed tissue, and clinical results were evaluated. The average postoperative follow-up period was 31 months (range, 24 to 43 months). Preoperative T2-weighted MRI in all cases revealed that chronically ruptured Achilles tendons were thickened and fusiform-shaped with diffuse intratendinous high-signal alterations throughout. Longitudinal high-signal bands were seen throughout the tendon, except at the musculotendinous junction and insertion on the calcaneus. Histologically, scar tissue interposed between the tendon stumps consisted of dense collagen fibers, and degenerative changes were not seen. After surgery, no patient had difficulty in walking or stair climbing, and all were able to perform a single-limb toe raise. The mean preoperative and postoperative American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot scores were 88.2 and 98.3 points, respectively; the difference was statistically significant (P = .0277). Interposed tissue between the tendon stumps is suitable for repair of chronic Achilles tendon rupture if preoperative MRI shows a thickened fusiform-shaped Achilles tendon with diffuse intratendinous high-signal alterations throughout.

The Achilles Tendon in Healthy Subjects: An Anthropometric and Ultrasound Mapping Study.

PubMed

Patel, Nick N; Labib, Sameh A

Ultrasonography is an inexpensive, fast, and reliable imaging technique widely used to assess the Achilles tendon. Although significant data exists regarding pathologic tendon changes, ultrasound data from healthy individuals are more limited. We aimed to better characterize ultrasound Achilles tendon measurements in healthy individuals and identify important correlating factors. The information collected included patient demographics, body habitus, activity level, foot dominance, and resting ankle angle. Ultrasound analysis was performed bilaterally on the Achilles tendons of 50 subjects using a high-frequency transducer to measure tendon width, thickness, cross-sectional area, and length. Males had a significantly larger mean tendon length, width, thickness, and cross-sectional area. No statistically significant difference was found in any tendon dimension between the white and black participants. Similarly, no difference was found in any tendon parameter when comparing right versus left leg dominance. Healthy subjects had a mean ankle resting angle of 45.1° ± 24° with no statistically significant difference between right and left ankles. Considering all individuals, each tendon parameter (tendon length, width, thickness, and cross-sectional area) correlated positively with subject height, weight, tibia length, and foot size. Only the Achilles cross-sectional area correlated significantly with the activity level. The resting angle of the ankle correlated positively with both tendon length and thickness. In conclusion, we found significant variations in Achilles tendon anatomy in the healthy adult population. We have thoroughly characterized significant correlations between healthy tendon dimensions and various body habitus, activity levels, and ankle parameters. Greater knowledge of the normal Achilles tendon anatomy and characterization of its variations in the healthy population will potentially allow for better pathologic diagnosis and surgical repair. Copyright © 2017 The American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

The flexor digitorum profundus "demi-tendon"--a new technique for passage of the flexor profundus tendon through the A4 pulley.

PubMed

Elliot, D; Khandwala, A R; Ragoowansi, R

2001-10-01

The flexor digitorum profundus (FDP) tendon may retract after avulsion or division in Zone 1. When treatment has been delayed, the oedematous tendon can be too swollen to pass freely through the A4 pulley. We present a new technique for dealing with this situation which depends on the "double-barrelled" nature of the distal part of the FDP tendon. One half of the tendon is excised longitudinally and the remaining "demi-tendon" is passed through the intact A4 pulley to allow tendon repair or re-attachment. This technique has been used in six cases in which passage of the FDP tendon through the A4 pulley would otherwise have been impossible. Copyright 2001 The British Society for Surgery of the Hand.

[Ultrastructural observation of tendonization of artificial tendon 109HH in rabbit].

PubMed

Liu, L; Cao, Q; Xiao, H

1995-09-01

Ten New Zealand rabbits were divided into 5 groups at random. Calcaneal tendons were cut bilaterally, then atificial tendon 109HH was used to connect the two ends of the cut tendon. Ultrastructural changes of control group and experimental groups at 2, 6, 12, 28 weeks after section were observed. The results showed that fibroblast proliferated and a lot of ribosome and RER appeared in plasm during 2 approximately 6 weeks, indicating artificial tendon caused fibroblast proliferation. During this period, fibroblast over synthesized collagenous protein and the synthesis of collagenous fibers peaked. During 12-28 weeks, the number of fibroblasts and the synthesis of collagenous protein decreased. Finally, fibroblasts became inactive tendon cells. With the formation of new tendons, the artificial tendens were degradated and absorbed, and disappeared after 12 weeks. The new tendon fibers became thicker and had the correct direction through reconstruction. The structure and function of new tendons could be restored to be consistent with normal values.

Central Tendon Injuries of Hamstring Muscles: Case Series of Operative Treatment.

PubMed

Lempainen, Lasse; Kosola, Jussi; Pruna, Ricard; Puigdellivol, Jordi; Sarimo, Janne; Niemi, Pekka; Orava, Sakari

2018-02-01

As compared with injuries involving muscle only, those involving the central hamstring tendon have a worse prognosis. Limited information is available regarding the surgical treatment of central tendon injuries of the hamstrings. To describe the operative treatment and outcomes of central tendon injuries of the hamstrings among athletes. Case series; Level of evidence, 4. Eight athletes (6 top level, 2 recreational) with central hamstring tendon injuries underwent magnetic resonance imaging and surgical treatment. The indication for surgery was recurrent (n = 6) or acute (n = 2) central hamstring tendon injury. All patients followed the same postoperative rehabilitation protocol, and return to play was monitored. Magnetic resonance imaging found a central tendon injury in all 3 hamstring muscles (long head of the biceps femoris, semimembranosus, and semitendinosus) with disrupted tendon ends. In acute and recurrent central tendon injuries, full return to play was achieved at 2.5 to 4 months. There were no adverse events during follow-up. Central tendon injuries of the hamstrings can be successfully repaired surgically after acute and recurrent ruptures.

Angiogenesis in healing autogenous flexor-tendon grafts.

PubMed

Gelberman, R H; Chu, C R; Williams, C S; Seiler, J G; Amiel, D

1992-09-01

On the basis of recent evidence that flexor tendon grafts may heal without the ingrowth of vascular adhesions, eighteen autogenous donor tendons of intrasynovial and extrasynovial origin were transferred to the synovial sheaths in the forepaws of nine dogs, and controlled passive mobilization was instituted early in the postoperative period. The angiogenic responses of the tendon grafts were determined with perfusion studies with India ink followed by cleaing of the tissues with the Spalteholz technique at two, four, and six weeks. A consistent pattern of neovascularization was noted in the donor tendons of extrasynovial origin. Vascular adhesions arising from the flexor digitorum superficialis and the tendon sheath enveloped the tendon grafts by two weeks. By six weeks, the vascularity of the tendon grafts of extrasynovial origin appeared completely integrated with that of the surrounding tissues. Examination of cross sections revealed that the segments of tendon had been completely vascularized by obliquely oriented intratendinous vessels. In contrast, the flexor tendon grafts of intrasynovial origin healed without ingrowth of vascular adhesions. Primary intrinsic neovascularization took place from the proximal and, to a lesser extent, distal sites of the sutures. Examination of cross sections revealed vessels extending through the surface layer of the tendon graft, with small vessels penetrating the interior of the tendons at regular intervals.

Postinjury biomechanics of Achilles tendon vary by sex and hormone status

PubMed Central

Fryhofer, George W.; Freedman, Benjamin R.; Hillin, Cody D.; Salka, Nabeel S.; Pardes, Adam M.; Weiss, Stephanie N.; Farber, Daniel C.

2016-01-01

Achilles tendon ruptures are common injuries. Sex differences are present in mechanical properties of uninjured Achilles tendon, but it remains unknown if these differences extend to tendon healing. We hypothesized that ovariectomized females (OVX) and males would exhibit inferior postinjury tendon properties compared with females. Male, female, and OVX Sprague-Dawley rats (n = 32/group) underwent acclimation and treadmill training before blunt transection of the Achilles tendon midsubstance. Injured hindlimbs were immobilized for 1 wk, followed by gradual return to activity and assessment of active and passive hindlimb function. Animals were euthanized at 3 or 6 wk postinjury to assess tendon structure, mechanics, and composition. Passive ankle stiffness and range of motion were superior in females at 3 wk; however, by 6 wk, passive and active function were similar in males and females but remained inferior in OVX. At 6 wk, female tendons had greater normalized secant modulus, viscoelastic behavior, and laxity compared with males. Normalized secant modulus, cross-sectional area and tendon glycosaminoglycan composition were inferior in OVX compared with females at 6 wk. Total fatigue cycles until tendon failure were similar among groups. Postinjury muscle fiber size was better preserved in females compared with males, and females had greater collagen III at the tendon injury site compared with males at 6 wk. Despite male and female Achilles tendons withstanding similar durations of fatigue loading, early passive hindlimb function and tendon mechanical properties, including secant modulus, suggest superior healing in females. Ovarian hormone loss was associated with inferior Achilles tendon healing. PMID:27633741

The effect of mechanical stimulation on the maturation of TDSCs-poly(L-lactide-co-e-caprolactone)/collagen scaffold constructs for tendon tissue engineering.

PubMed

Xu, Yuan; Dong, Shiwu; Zhou, Qiang; Mo, Xiumei; Song, Lei; Hou, Tianyong; Wu, Jinglei; Li, Songtao; Li, Yudong; Li, Pei; Gan, Yibo; Xu, Jianzhong

2014-03-01

Mechanical stimulation plays an important role in the development and remodeling of tendons. Tendon-derived stem cells (TDSCs) are an attractive cell source for tendon injury and tendon tissue engineering. However, these cells have not yet been fully explored for tendon tissue engineering application, and there is also lack of understanding to the effect of mechanical stimulation on the maturation of TDSCs-scaffold construct for tendon tissue engineering. In this study, we assessed the efficacy of TDSCs in a poly(L-lactide-co-ε-caprolactone)/collagen (P(LLA-CL)/Col) scaffold under mechanical stimulation for tendon tissue engineering both in vitro and in vivo, and evaluated the utility of the transplanted TDSCs-scaffold construct to promote rabbit patellar tendon defect regeneration. TDSCs displayed good proliferation and positive expressed tendon-related extracellular matrix (ECM) genes and proteins under mechanical stimulation in vitro. After implanting into the nude mice, the fluorescence imaging indicated that TDSCs had long-term survival, and the macroscopic evaluation, histology and immunohistochemistry examinations showed high-quality neo-tendon formation under mechanical stimulation in vivo. Furthermore, the histology, immunohistochemistry, collagen content assay and biomechanical testing data indicated that dynamically cultured TDSCs-scaffold construct could significantly contributed to tendon regeneration in a rabbit patellar tendon window defect model. TDSCs have significant potential to be used as seeded cells in the development of tissue-engineered tendons, which can be successfully fabricated through seeding of TDSCs in a P(LLA-CL)/Col scaffold followed by mechanical stimulation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Informing Stem Cell-Based Tendon Tissue Engineering Approaches with Embryonic Tendon Development.

PubMed

Okech, William; Kuo, Catherine K

Adult tendons fail to regenerate normal tissue after injury, and instead form dysfunctional scar tissue with abnormal mechanical properties. Surgical repair with grafts is the current standard to treat injuries, but faces significant limitations including pain and high rates of re-injury. To address this, we aim to regenerate new, normal tendons to replace dysfunctional tendons. A common approach to tendon tissue engineering is to design scaffolds and bioreactors based on adult tendon properties that can direct adult stem cell tenogenesis. Despite significant progress, advances have been limited due, in part, to a need for markers and potent induction cues. Our goal is to develop novel tendon tissue engineering approaches informed by embryonic tendon development. We are characterizing structure-property relationships of embryonic tendon to identify design parameters for three-dimensional scaffolds and bioreactor mechanical loading systems to direct adult stem cell tenogenesis. We will review studies in which we quantified changes in the mechanical and biochemical properties of tendon during embryonic development and elucidated specific mechanisms of functional property elaboration. We then examined the effects of these mechanical and biochemical factors on embryonic tendon cell behavior. Using custom-designed bioreactors, we also examined the effects of dynamic mechanical loading and growth factor treatment on embryonic tendon cells. Our findings have established cues to induce tenogenesis as well as metrics to evaluate differentiation. We finish by discussing how we have evaluated the tenogenic differentiation potential of adult stem cells by comparing their responses to that of embryonic tendon cells in these culture systems.

Tendon material properties vary and are interdependent among turkey hindlimb muscles

PubMed Central

Matson, Andrew; Konow, Nicolai; Miller, Samuel; Konow, Pernille P.; Roberts, Thomas J.

2012-01-01

SUMMARY The material properties of a tendon affect its ability to store and return elastic energy, resist damage, provide mechanical feedback and amplify or attenuate muscle power. While the structural properties of a tendon are known to respond to a variety of stimuli, the extent to which material properties vary among individual muscles remains unclear. We studied the tendons of six different muscles in the hindlimb of Eastern wild turkeys to determine whether there was variation in elastic modulus, ultimate tensile strength and resilience. A hydraulic testing machine was used to measure tendon force during quasi-static lengthening, and a stress–strain curve was constructed. There was substantial variation in tendon material properties among different muscles. Average elastic modulus differed significantly between some tendons, and values for the six different tendons varied nearly twofold, from 829±140 to 1479±106 MPa. Tendons were stretched to failure, and the stress at failure, or ultimate tensile stress, was taken as a lower-limit estimate of tendon strength. Breaking tests for four of the tendons revealed significant variation in ultimate tensile stress, ranging from 66.83±14.34 to 112.37±9.39 MPa. Resilience, or the fraction of energy returned in cyclic length changes was generally high, and one of the four tendons tested was significantly different in resilience from the other tendons (range: 90.65±0.83 to 94.02±0.71%). An analysis of correlation between material properties revealed a positive relationship between ultimate tensile strength and elastic modulus (r2=0.79). Specifically, stiffer tendons were stronger, and we suggest that this correlation results from a constrained value of breaking strain, which did not vary significantly among tendons. This finding suggests an interdependence of material properties that may have a structural basis and may explain some adaptive responses observed in studies of tendon plasticity. PMID:22771746

Tendon material properties vary and are interdependent among turkey hindlimb muscles.

PubMed

Matson, Andrew; Konow, Nicolai; Miller, Samuel; Konow, Pernille P; Roberts, Thomas J

2012-10-15

The material properties of a tendon affect its ability to store and return elastic energy, resist damage, provide mechanical feedback and amplify or attenuate muscle power. While the structural properties of a tendon are known to respond to a variety of stimuli, the extent to which material properties vary among individual muscles remains unclear. We studied the tendons of six different muscles in the hindlimb of Eastern wild turkeys to determine whether there was variation in elastic modulus, ultimate tensile strength and resilience. A hydraulic testing machine was used to measure tendon force during quasi-static lengthening, and a stress-strain curve was constructed. There was substantial variation in tendon material properties among different muscles. Average elastic modulus differed significantly between some tendons, and values for the six different tendons varied nearly twofold, from 829±140 to 1479±106 MPa. Tendons were stretched to failure, and the stress at failure, or ultimate tensile stress, was taken as a lower-limit estimate of tendon strength. Breaking tests for four of the tendons revealed significant variation in ultimate tensile stress, ranging from 66.83±14.34 to 112.37±9.39 MPa. Resilience, or the fraction of energy returned in cyclic length changes was generally high, and one of the four tendons tested was significantly different in resilience from the other tendons (range: 90.65±0.83 to 94.02±0.71%). An analysis of correlation between material properties revealed a positive relationship between ultimate tensile strength and elastic modulus (r(2)=0.79). Specifically, stiffer tendons were stronger, and we suggest that this correlation results from a constrained value of breaking strain, which did not vary significantly among tendons. This finding suggests an interdependence of material properties that may have a structural basis and may explain some adaptive responses observed in studies of tendon plasticity.

[Clinical application of peroneal muscles tendon transposition in repair of Achilles tendon rupture].

PubMed

Jin, Rihao; Jin, Yu; Fang, Xiulin

2006-07-01

To discuss applied anatomy, biomechanics and surgical procedures of long peroneal muscles tendon transposition in repair of occlusive achilles tendon rupture. The blood supply and the morphology of long peroneal muscles tendon were observed in the lower extremity of 50 sides adult specimens and the mechanical tests which stretch load on the tendon were carried out. The methods were designed on the basis of the anatomical characteristics and morphology. Ten patients suffering occlusive Achilles tendon rupture were treated by using long peroneal muscles tendon transposition from March 2001 to July 2004. Among 10 patients, there were 7 males and 3 females, aging 32 to 54 years including 6 cases of jump injury, 2 cases of bruise, 1 case of step vacancy and 1 case of spontaneity injury. The interval between injury and surgery was 6 hours to 7 days in 7 fresh rupture and 21 days to 3 months in 3 old rupture. All cases belonged to occlusive Achilles tendon rupture (8 cases of complete rupture and 2 cases of incomplete rupture). The origin of long peroneal muscles was proximal tibia and fibular head, the end of them was base of first metatarsal bones and medial cuboid. The length of tendon was 13.5 +/- 2.5 cm. The width of origin tendon was 0.9 +/- 0.2 cm and the thickness was 0.3 +/- 0.1 cm; the width on apex of lateral malleolus was 0.7 +/- 0.1 cm and the thickness was 0.4 +/- 0.1 cm, the width on head of cuboid was 0.7 +/- 0.1 cm and the thickness was 0.3 +/- 0.1 cm. The long peroneal muscles tendon had abundant blood supply. The results of mechanical test showed that the biggest load was 2,292.4 +/- 617.3 N on tendon calcaneus, 1,020.4 +/- 175.4 N on long peroneal muscles tendon, 752.0 +/- 165.4 N on peroneus brevis tendon and 938.2 +/- 216.7 N on tibialis posterior tendon. Ten cases of occlusive Achilles tendon rupture achieved healing by first intention and were followed up 18-24 months. No Achilles tendon re-rupture, necrosis of skin or other complications occurred. According to Amerind-holm criterion for curative results, the results were excellent in 7 cases and good in 3 cases and the excellent and good rate was 100%. The long peroneal muscles tendon transposition is a perfect and simple way to repair occlusive Achilles tendon rupture.

The revitalisation of flexor tendon allografts with bone marrow stromal cells and mechanical stimulation: An ex vivo model revitalising flexor tendon allografts.

PubMed

Wu, J H; Thoreson, A R; Gingery, A; An, K N; Moran, S L; Amadio, P C; Zhao, C

2017-03-01

The present study describes a novel technique for revitalising allogenic intrasynovial tendons by combining cell-based therapy and mechanical stimulation in an ex vivo canine model. Specifically, canine flexor digitorum profundus tendons were used for this study and were divided into the following groups: (1) untreated, unprocessed normal tendon; (2) decellularised tendon; (3) bone marrow stromal cell (BMSC)-seeded tendon; and (4) BMSC-seeded and cyclically stretched tendon. Lateral slits were introduced on the tendon to facilitate cell seeding. Tendons from all four study groups were distracted by a servohydraulic testing machine. Tensile force and displacement data were continuously recorded at a sample rate of 20 Hz until 200 Newton of force was reached. Before testing, the cross-sectional dimensions of each tendon were measured with a digital caliper. Young's modulus was calculated from the slope of the linear region of the stress-strain curve. The BMSCs were labeled for histological and cell viability evaluation on the decellularized tendon scaffold under a confocal microscope. Gene expression levels of selected extracellular matrix tendon growth factor genes were measured. Results were reported as mean ± SD and data was analyzed with one-way ANOVAs followed by Tukey's post hoc multiple-comparison test. We observed no significant difference in cross-sectional area or in Young's modulus among the four study groups. In addition, histological sections showed that the BMSCs were aligned well and viable on the tendon slices after two-week culture in groups three and four. Expression levels of several extracellular matrix tendon growth factors, including collagen type I, collagen type III, and matrix metalloproteinase were significantly higher in group four than in group three (p < 0.05). Lateral slits introduced into de-cellularised tendon is a promising method of delivery of BMSCs without compromising cell viability and tendon mechanical properties. In addition, mechanical stimulation of a cell-seeded tendon can promote cell proliferation and enhance expression of collagen types I and III in vitro . Cite this article: J. H. Wu, A. R. Thoreson, A. Gingery, K. N. An, S. L. Moran, P. C. Amadio, C. Zhao. The revitalisation of flexor tendon allografts with bone marrow stromal cells and mechanical stimulation: An ex vivo model revitalising flexor tendon allografts. Bone Joint Res 2017;6:179-185. DOI: 10.1302/2046-3758.63.BJR-2016-0207.R1. © 2017 Zhao et al.

The Role of Mechanical Loading in Tendon Development, Maintenance, Injury, and Repair

PubMed Central

Galloway, Marc T.; Lalley, Andrea L.; Shearn, Jason T.

2013-01-01

➤ Tendon injuries often result from excessive or insufficient mechanical loading, impairing the ability of the local tendon cell population to maintain normal tendon function. ➤ The resident cell population composing tendon tissue is mechanosensitive, given that the cells are able to alter the extracellular matrix in response to modifications of the local loading environment. ➤ Natural tendon healing is insufficient, characterized by improper collagen fibril diameter formation, collagen fibril distribution, and overall fibril misalignment. ➤ Current tendon repair rehabilitation protocols focus on implementing early, well-controlled eccentric loading exercises to improve repair outcome. ➤ Tissue engineers look toward incorporating mechanical loading regimens to precondition cell populations for the creation of improved biological augmentations for tendon repair. PMID:24005204

Lipids, adiposity and tendinopathy: is there a mechanistic link? Critical review

PubMed Central

Scott, Alex; Zwerver, Johannes; Grewal, Navi; de Sa, Agnetha; Alktebi, Thuraya; Granville, David J; Hart, David A

2015-01-01

Being overweight or obese is associated with an elevated risk of tendon pathology. However, for sportspeople the epidemiological data linking weight or adiposity on one hand, and risk of tendon pathology on the other, are less consistent. Indeed, the mechanistic links between diet, adiposity and tendon pathology remain largely unexamined. Recent studies have begun to examine the effects of dietary interventions on outcomes such as tendon biomechanics or pain. Oxidised low-density lipoprotein has been shown to (A) accumulate in the tendon tissues of mice that eat a fatty diet and (B) induce a pathological phenotype in human tendon cells. This paper addresses the current debate: is excessive body mass index (causing increased load and strain on tendon tissue) per se the underlying mechanism? Or do local or systemic influences of fat on tendons predispose to tendon pathology? This narrative review argues that excessive blood lipids may be an important avenue for clinical investigations. PMID:25488953

Therapeutics for tendon regeneration: a multidisciplinary review of tendon research for improved healing.

PubMed

Paredes, J J; Andarawis-Puri, Nelly

2016-11-01

Tendon injuries, known as tendinopathies, are common musculoskeletal injuries that affect a wide range of the population. Canonical tendon healing is characterized by fibrosis, scar formation, and the loss of tissue mechanical and structural properties. Understanding the regenerative tendon environment is an area of increasing interest in the field of musculoskeletal research. Previous studies have focused on utilizing individual elements from the fields of biomechanics, developmental biology, cell and growth factor therapy, and tissue engineering in an attempt to develop regenerative tendon therapeutics. Still, the specific mechanism for regenerative healing remains unknown. In this review, we highlight some of the current approaches of tendon therapeutics and elucidate the differences along the tendon midsubstance and enthesis, exhibiting the necessity of location-specific tendon therapeutics. Furthermore, we emphasize the necessity of further interdisciplinary research in order to reach the desired goal of fully understanding the mechanisms underlying regenerative healing. © 2016 New York Academy of Sciences.

Robot Arm with Tendon Connector Plate and Linear Actuator

NASA Technical Reports Server (NTRS)

Bridgwater, Lyndon (Inventor); Millerman, Alexander (Inventor); Ihrke, Chris A. (Inventor); Diftler, Myron A. (Inventor); Nguyen, Vienny (Inventor)

2014-01-01

A robotic system includes a tendon-driven end effector, a linear actuator, a flexible tendon, and a plate assembly. The linear actuator assembly has a servo motor and a drive mechanism, the latter of which translates linearly with respect to a drive axis of the servo motor in response to output torque from the servo motor. The tendon connects to the end effector and drive mechanism. The plate assembly is disposed between the linear actuator assembly and the tendon-driven end effector and includes first and second plates. The first plate has a first side that defines a boss with a center opening. The second plate defines an accurate through-slot having tendon guide channels. The first plate defines a through passage for the tendon between the center opening and a second side of the first plate. A looped end of the flexible tendon is received within the tendon guide channels.

Peroneal tendon pathology: Pre- and post-operative high resolution US and MR imaging.

PubMed

Kumar, Yogesh; Alian, Ali; Ahlawat, Shivani; Wukich, Dane K; Chhabra, Avneesh

2017-07-01

Peroneal tendon pathology is an important cause of lateral ankle pain and instability. Typical peroneal tendon disorders include tendinitis, tenosynovitis, partial and full thickness tendon tears, peroneal retinacular injuries, and tendon subluxations and dislocations. Surgery is usually indicated when conservative treatment fails. Familiarity with the peroneal tendon surgeries and expected postoperative imaging findings is essential for accurate assessment and to avoid diagnostic pitfalls. Cross-sectional imaging, especially ultrasound and MRI provide accurate pre-operative and post-operative evaluation of the peroneal tendon pathology. In this review article, the normal anatomy, clinical presentation, imaging features, pitfalls and commonly performed surgical treatments for peroneal tendon abnormalities will be reviewed. The role of dynamic ultrasound and kinematic MRI for the evaluation of peroneal tendons will be discussed. Normal and abnormal postsurgical imaging appearances will be illustrated. Copyright © 2017 Elsevier B.V. All rights reserved.

Mechanisms of tendon injury and repair

PubMed Central

Thomopoulos, Stavros; Parks, William C.; Rifkin, Daniel B.; Derwin, Kathleen A.

2015-01-01

Tendon disorders are common and lead to significant disability, pain, healthcare cost, and lost productivity. A wide range of injury mechanisms exist leading to tendinopathy or tendon rupture. Tears can occur in healthy tendons that are acutely overloaded (e.g., during a high speed or high impact event) or lacerated (e.g., a knife injury). Tendinitis or tendinosis can occur in tendons exposed to overuse conditions (e.g., an elite swimmer’s training regimen) or intrinsic tissue degeneration (e.g., age-related degeneration). The healing potential of a torn or pathologic tendon varies depending on anatomic location (e.g., Achilles vs. rotator cuff) and local environment (e.g., intrasynovial vs. extrasynovial). Although healing occurs to varying degrees, in general healing of repaired tendons follows the typical wound healing course, including an early inflammatory phase, followed by proliferative and remodeling phases. Numerous treatment approaches have been attempted to improve tendon healing, including growth factor- and cell-based therapies and rehabilitation protocols. This review will describe the current state of knowledge of injury and repair of the three most common tendinopathies-- flexor tendon lacerations, Achilles tendon rupture, and rotator cuff disorders-- with a particular focus on the use of animal models for understanding tendon healing. PMID:25641114

Neuronal regulation of tendon homoeostasis

PubMed Central

Ackermann, Paul W

2013-01-01

The regulation of tendon homoeostasis, including adaptation to loading, is still not fully understood. Accumulating data, however, demonstrates that in addition to afferent (sensory) functions, the nervous system, via efferent pathways which are associated with through specific neuronal mediators plays an active role in regulating pain, inflammation and tendon homeostasis. This neuronal regulation of intact-, healing- and tendinopathic tendons has been shown to be mediated by three major groups of molecules including opioid, autonomic and excitatory glutamatergic neuroregulators. In intact healthy tendons the neuromediators are found in the surrounding structures: paratenon, endotenon and epitenon, whereas the proper tendon itself is practically devoid of neurovascular supply. This neuroanatomy reflects that normal tendon homoeostasis is regulated from the tendon surroundings. After injury and during tendon repair, however, there is extensive nerve ingrowth into the tendon proper, followed by a time-dependent emergence of sensory, autonomic and glutamatergic mediators, which amplify and fine-tune inflammation and regulate tendon regeneration. In tendinopathic condition, excessive and protracted presence of sensory and glutamatergic neuromediators has been identified, suggesting involvement in inflammatory, nociceptive and hypertrophic (degenerative) tissue responses. Under experimental and clinical conditions of impaired (e.g. diabetes) as well as excessive (e.g. tendinopathy) neuromediator release, dysfunctional tendon homoeostasis develops resulting in chronic pain and gradual degeneration. Thus there is a prospect that in the future pharmacotherapy and tissue engineering approaches targeting neuronal mediators and their receptors may prove to be effective therapies for painful, degenerative and traumatic tendon disorders. PMID:23718724

Peroneal tendon displacement accompanying intra-articular calcaneal fractures.

PubMed

Toussaint, Rull James; Lin, Darius; Ehrlichman, Lauren K; Ellington, J Kent; Strasser, Nicholas; Kwon, John Y

2014-02-19

Peroneal tendon displacement (subluxation or dislocation) accompanying an intra-articular calcaneal fracture is often undetected and under-treated. The goals of this study were to determine (1) the prevalence of peroneal tendon displacement accompanying intra-articular calcaneal fractures, (2) the association of tendon displacement with fracture classifications, (3) the association of tendon displacement with heel width, and (4) the rate of missed diagnosis of the tendon displacement on radiographs and computed tomography (CT) scans and the resulting treatment rate. A retrospective radiographic review of all calcaneal fractures presenting at three institutions from June 30, 2006, to June 30, 2011, was performed. CT imaging of 421 intra-articular calcaneal fractures involving the posterior facet was available for review. The prevalence of peroneal tendon displacement was noted and its associations with fracture classification and heel width were evaluated. Peroneal tendon displacement was identified in 118 (28.0%) of the 421 calcaneal fracture cases. The presence of tendon displacement was significantly associated with joint-depression fractures compared with tongue-type fractures (p < 0.001). Only twelve (10.2%) of the 118 cases of peroneal tendon displacement had been identified in the radiology reports. Although sixty-five (55.1%) of the fractures with tendon displacement had been treated with internal fixation, the tendon displacement was treated surgically in only seven (10.8%) of these cases. Analysis of CT images showed a 28% prevalence of peroneal tendon displacement accompanying intra-articular calcaneal fractures. Surgeons and radiologists are encouraged to consider this association.

Using the zebrafish to understand tendon development and repair

PubMed Central

Chen, Jessica W.; Galloway, Jenna L.

2017-01-01

Tendons are important components of our musculoskeletal system. Injuries to these tissues are very common, resulting from occupational-related injuries, sports-related trauma, and age-related degeneration. Unfortunately, there are few treatment options, and current therapies rarely restore injured tendons to their original function. An improved understanding of the pathways regulating their development and repair would have significant impact in stimulating the formulation of regenerative-based approaches for tendon injury. The zebrafish provides an ideal system in which to perform genetic and chemical screens to identify new pathways involved in tendon biology. Until recently, there had been few descriptions of tendons and ligaments in the zebrafish and their similarity to mammalian tendon tissues. In this chapter, we describe the development of the zebrafish tendon and ligament tissues in the context of their gene expression, structure, and interactions with neighboring musculoskeletal tissues. We highlight the similarities with tendon development in higher vertebrates, showing that the craniofacial tendons and ligaments in zebrafish morphologically, molecularly, and structurally resemble mammalian tendons and ligaments from embryonic to adult stages. We detail methods for fluorescent in situ hybridization and immunohistochemistry as an assay to examine morphological changes in the zebrafish musculoskeleton. Staining assays such as these could provide the foundation for screen-based approaches to identify new regulators of tendon development, morphogenesis, and repair. These discoveries would provide new targets and pathways to study in the context of regenerative medicine-based approaches to improve tendon healing. PMID:28129848

Continuous Shear Wave Elastography: a New Method to Measure in-vivo Viscoelastic Properties of Tendons

PubMed Central

Cortes, Daniel H.; Suydam, Stephen M.; Silbernagel, Karin Grävare; Buchanan, Thomas S.; Elliott, Dawn M.

2015-01-01

Viscoelastic mechanical properties are frequently altered after tendon injuries and during recovery. Therefore, non-invasive measurements of shear viscoelastic properties may help evaluate tendon recovery and compare the effectiveness of different therapies. The objectives of this study are to present an elastography method to measure localized viscoelastic properties of tendon and to present initial results in healthy and injured human Achilles and semitendinosus tendons. The technique used an external actuator to generate the shear waves in the tendon at different frequencies and plane wave imaging to measure shear wave displacements. For each of the excitation frequencies, maps of direction specific wave speeds were calculated using Local Frequency Estimation. Maps of viscoelastic properties were obtained using a pixel wise curve-fit of wave speed and frequency. The method was validated by comparing measurements of wave speed in agarose gels to those obtained using magnetic resonance elastography. Measurements in human healthy Achilles tendons revealed a pronounced increase in wave speed as function of frequency that highlights the importance of tendon viscoelasticity. Additionally, the viscoelastic properties of the Achilles tendon were larger than those reported for other tissues. Measurements in a tendinopathic Achilles tendon showed that it is feasible to quantify local viscoeasltic properties. Similarly, measurement in the semitendinosus tendon showed a substantial differences in viscoelastic properties between the healthy and contralateral tendons. Consequently, this technique has the potential of evaluating localized changes in tendon viscoelastic properties due to injury and during recovery in a clinical setting. PMID:25796414

An Overview of the Management of Flexor Tendon Injuries

PubMed Central

Griffin, M; Hindocha, S; Jordan, D; Saleh, M; Khan, W

2012-01-01

Flexor tendon injuries still remain a challenging condition to manage to ensure optimal outcome for the patient. Since the first flexor tendon repair was described by Kirchmayr in 1917, several approaches to flexor tendon injury have enabled successful repairs rates of 70-90%. Primary surgical repair results in better functional outcome compared to secondary repair or tendon graft surgery. Flexor tendon injury repair has been extensively researched and the literature demonstrates successful repair requires minimal gapping at the repair site or interference with tendon vascularity, secure suture knots, smooth junction of tendon end and having sufficient strength for healing. However, the exact surgical approach to achieve success being currently used among surgeons is still controversial. Therefore, this review aims to discuss the results of studies demonstrating the current knowledge regarding the optimal approach for flexor tendon repair. Post-operative rehabilitation for flexor tendon surgery is another area, which has caused extensive debate in hand surgery. The trend to more active mobilisation protocols seems to be favoured but further study in this area is needed to find the protocol, which achieves function and gliding but avoids rupture of the tendons. Lastly despite success following surgery complications commonly still occur post surgery, including adhesion formation, tendon rupture and stiffness of the joints. Therefore, this review aims to discuss the appropriate management of these difficulties post surgery. New techniques in management of flexor tendon will also be discussed including external laser devices, addition of growth factors and cytokines. PMID:22431948

Effect of Implanting a Soft Tissue Autograft in a Central-Third Patellar Tendon Defect: Biomechanical and Histological Comparisons

PubMed Central

Kinneberg, Kirsten R. C.; Galloway, Marc T.; Butler, David L.; Shearn, Jason T.

2011-01-01

Previous studies by our laboratory have demonstrated that implanting a stiffer tissue engineered construct at surgery is positively correlated with repair tissue stiffness at 12 weeks. The objective of this study was to test this correlation by implanting a construct that matches normal tissue biomechanical properties. To do this, we utilized a soft tissue patellar tendon autograft to repair a central-third patellar tendon defect. Patellar tendon auto-graft repairs were contrasted against an unfilled defect repaired by natural healing (NH). We hypothesized that after 12 weeks, patellar tendon autograft repairs would have biomechanical properties superior to NH. Bilateral defects were established in the central-third patellar tendon of skeletally mature (one year old), female New Zealand White rabbits (n = 10). In one limb, the excised tissue, the patellar tendon autograft, was sutured into the defect site. In the contralateral limb, the defect was left empty (natural healing). After 12 weeks of recovery, the animals were euthanized and their limbs were dedicated to bio-mechanical (n = 7) or histological (n = 3) evaluations. Only stiffness was improved by treatment with patellar tendon autograft relative to natural healing (p = 0.009). Additionally, neither the patellar tendon autograft nor natural healing repairs regenerated a normal zonal insertion site between the tendon and bone. Immunohistochemical staining for collagen type II demonstrated that fibrocartilage-like tissue was regenerated at the tendon-bone interface for both repairs. However, the tissue was disorganized. Insufficient tissue integration at the tendon-to-bone junction led to repair tissue failure at the insertion site during testing. It is important to re-establish the tendon-to-bone insertion site because it provides joint stability and enables force transmission from muscle to tendon and subsequent loading of the tendon. Without loading, tendon mechanical properties deteriorate. Future studies by our laboratory will investigate potential strategies to improve patellar tendon autograft integration into bone using this model. [DOI: 10.1115/1.4004948] PMID:22010737

The promoting effect of pentadecapeptide BPC 157 on tendon healing involves tendon outgrowth, cell survival, and cell migration.

PubMed

Chang, Chung-Hsun; Tsai, Wen-Chung; Lin, Miao-Sui; Hsu, Ya-Hui; Pang, Jong-Hwei Su

2011-03-01

Pentadecapeptide BPC 157, composed of 15 amino acids, is a partial sequence of body protection compound (BPC) that is discovered in and isolated from human gastric juice. Experimentally it has been demonstrated to accelerate the healing of many different wounds, including transected rat Achilles tendon. This study was designed to investigate the potential mechanism of BPC 157 to enhance healing of injured tendon. The outgrowth of tendon fibroblasts from tendon explants cultured with or without BPC 157 was examined. Results showed that BPC 157 significantly accelerated the outgrowth of tendon explants. Cell proliferation of cultured tendon fibroblasts derived from rat Achilles tendon was not directly affected by BPC 157 as evaluated by MTT assay. However, the survival of BPC 157-treated cells was significantly increased under the H(2)O(2) stress. BPC 157 markedly increased the in vitro migration of tendon fibroblasts in a dose-dependent manner as revealed by transwell filter migration assay. BPC 157 also dose dependently accelerated the spreading of tendon fibroblasts on culture dishes. The F-actin formation as detected by FITC-phalloidin staining was induced in BPC 157-treated fibroblasts. The protein expression and activation of FAK and paxillin were determined by Western blot analysis, and the phosphorylation levels of both FAK and paxillin were dose dependently increased by BPC 157 while the total amounts of protein was unaltered. In conclusion, BPC 157 promotes the ex vivo outgrowth of tendon fibroblasts from tendon explants, cell survival under stress, and the in vitro migration of tendon fibroblasts, which is likely mediated by the activation of the FAK-paxillin pathway.

Partial supraspinatus tears are associated with tendon lengthening.

PubMed

Farshad-Amacker, Nadja A; Buck, Florian M; Farshad, Mazda; Pfirrmann, Christian W A; Gerber, Christian

2015-02-01

Tendon tear may result in muscular retraction with the loss of contractile amplitude and strength of the rotator cuff muscles. Currently, neither a validated method of measuring supraspinatus tendon length nor normal values are known. It was therefore the purpose of this study to measure the normal length of the supraspinatus tendon and to determine whether partial tears are associated with changes in tendon length. MR examinations of 49 asymptomatic volunteers and 37 patients with arthroscopically proven, isolated partial tears of the supraspinatus tendon were compared. The ratio of the extramuscular tendon length to the distance between the footprint and the glenoid surface was calculated (TL/FG ratio). Tendon length measurements were taken by two independent readers at the bursal and articular surfaces at the anterior, the central and the posterior parts of the tendon. TL/FG ratios at the bursal surface of tendons with partial tears were significantly higher than those in the control group [anterior: 0.78 ± 0.20 vs. 0.66 ± 0.15 (p < 0.05); central: 0.61 ± 0.13 vs. 0.52 ± 0.10 (p < 0.05); posterior: 0.57 ± 0.15 vs. 0.52 ± 0.10 (p < 0.05)]. At the articular surface, differences were significant only anteriorly [0.60 ± 0.13, vs. 0.54 ± 0.10 (p < 0.05)]. A cut-off TL/FG ratio of 0.63 for measurements at the bursal surface in the center of the tendon achieved a sensitivity of 46 % and a specificity of 92 % for the identification of partial cuff tearing. A reproducible method for measurement of extramuscular supraspinatus tendon length is described. Partial tearing of the supraspinatus tendon is associated with significant tendon lengthening, suggesting failure in continuity, and this is most reliably measured on the bursal surface. III.

Experimental evaluation of multiscale tendon mechanics.

PubMed

Fang, Fei; Lake, Spencer P

2017-07-01

Tendon's primary function is a mechanical link between muscle and bone. The hierarchical structure of tendon and specific compositional constituents are believed to be critical for proper mechanical function. With increased appreciation for tendon importance and the development of various technological advances, this review paper summarizes recent experimental approaches that have been used to study multiscale tendon mechanics, includes an overview of studies that have evaluated the role of specific tissue constituents, and also proposes challenges/opportunities facing tendon study. Tendon has been demonstrated to have specific structural characteristics (e.g., multi-level hierarchy, crimp pattern, helix) and complex mechanical properties (e.g., non-linearity, anisotropy, viscoelasticity). Physical mechanisms including uncrimping, fiber sliding, and collagen reorganization have been shown to govern tendon mechanical responses under both static and dynamic loading. Several tendon constituents with relatively small quantities have been suggested to play a role in its mechanics, although some results are conflicting. Further research should be performed to understand the interplay and communication of tendon mechanical properties across levels of the hierarchical structure, and further show how each of these components contribute to tendon mechanics. The studies summarized and discussed in this review have helped elucidate important aspects of multiscale tendon mechanics, which is a prerequisite for analyzing stress/strain transfer between multiple scales and identifying key principles of mechanotransduction. This information could further facilitate interpreting the functional diversity of tendons from different species, different locations, and even different developmental stages, and then better understand and identify fundamental concepts related to tendon degeneration, disease, and healing. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1353-1365, 2017. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Tendon Reattachment to Bone in an Ovine Tendon Defect Model of Retraction Using Allogenic and Xenogenic Demineralised Bone Matrix Incorporated with Mesenchymal Stem Cells.

PubMed

Thangarajah, Tanujan; Shahbazi, Shirin; Pendegrass, Catherine J; Lambert, Simon; Alexander, Susan; Blunn, Gordon W

2016-01-01

Tendon-bone healing following rotator cuff repairs is mainly impaired by poor tissue quality. Demineralised bone matrix promotes healing of the tendon-bone interface but its role in the treatment of tendon tears with retraction has not been investigated. We hypothesized that cortical demineralised bone matrix used with minimally manipulated mesenchymal stem cells will result in improved function and restoration of the tendon-bone interface with no difference between xenogenic and allogenic scaffolds. In an ovine model, the patellar tendon was detached from the tibial tuberosity and a complete distal tendon transverse defect measuring 1 cm was created. Suture anchors were used to reattach the tendon and xenogenic demineralised bone matrix + minimally manipulated mesenchymal stem cells (n = 5), or allogenic demineralised bone matrix + minimally manipulated mesenchymal stem cells (n = 5) were used to bridge the defect. Graft incorporation into the tendon and its effect on regeneration of the enthesis was assessed using histomorphometry. Force plate analysis was used to assess functional recovery. Compared to the xenograft, the allograft was associated with significantly higher functional weight bearing at 6 (P = 0.047), 9 (P = 0.028), and 12 weeks (P = 0.009). In the allogenic group this was accompanied by greater remodeling of the demineralised bone matrix into tendon-like tissue in the region of the defect (p = 0.015), and a more direct type of enthesis characterized by significantly more fibrocartilage (p = 0.039). No failures of tendon-bone healing were noted in either group. Demineralised bone matrix used with minimally manipulated mesenchymal stem cells promotes healing of the tendon-bone interface in an ovine model of acute tendon retraction, with superior mechanical and histological results associated with use of an allograft.

Response of tibialis anterior tendon to a chronic exposure of stretch-shortening cycles: age effects

PubMed Central

Ensey, James S; Hollander, Melinda S; Wu, John Z; Kashon, Michael L; Baker, Brent B; Cutlip, Robert G

2009-01-01

Background The purpose of the current study was to investigate the effects of aging on tendon response to repetitive exposures of stretch-shortening cycles (SSC's). Methods The left hind limb from young (3 mo, N = 4) and old (30 mo, N = 9) male Fisher 344 × Brown Norway rats were exposed to 80 maximal SSCs (60 deg/s, 50 deg range of motion) 3x/week for 4.5 weeks in vivo. After the last exposure, tendons from the tibialis anterior muscle were isolated, stored at -80°C, and then tested using a micro-mechanical testing machine. Deformation of each tendon was evaluated using both relative grip-to-grip displacements and reference marks via a video system. Results At failure, the young control tendons had higher strain magnitude than the young exposed (p < 0.01) and the old control tendons (p < .0001). Total load at inflection was affected by age only (p < 0.01). Old exposed and control tendons exhibited significantly higher loads at the inflection point than their young counterparts (p < 0.05 for both comparisons). At failure, the old exposed tendons carried higher loads than the young exposed tendons (p < 0.05). Stiffness was affected by age only at failure where the old tendons exhibited higher stiffness in both exposed and control tendons than their young counterparts (p < 0.05 and p < 0.01, respectively). Conclusion The chronic protocol enhanced the elastic stiffness of young tendon and the loads in both the young and old tendons. The old exposed tendons were found to exhibit higher load capacity than their younger counterparts, which differed from our initial hypothesis. PMID:19563638

The biomechanical effects of limb lengthening and botulinum toxin type A on rabbit tendon.

PubMed

Olabisi, Ronke M; Best, Thomas M; Hurschler, Christof; Vanderby, Ray; Noonan, Kenneth J

2010-12-01

Numerous studies have examined the effects of distraction osteogenesis (DO) on bone, but relatively fewer have explored muscle adaptation, and even less have addressed the concomitant alterations that occur in the tendon. The purpose herein was to characterize the biomechanical properties of normal and elongated rabbit (N = 20) tendons with and without prophylactic botulinum toxin type A (BTX-A) treatment. Elastic and viscoelastic properties of Achilles and Tibialis anterior (TA) tendons were evaluated through pull to failure and stress relaxation tests. All TA tendons displayed nonlinear viscoelastic responses that were strain dependent. A power law formulation was used to model tendon viscoelastic responses and tendon elastic responses were fit with a microstructural model. Distraction-elongated tendons displayed increases in compliance and stress relaxation rates over undistracted tendons; BTX-A administration offset this result. The elastic moduli of distraction-lengthened TA tendons were diminished (p = 0.010) when distraction was combined with gastrocnemius (GA) BTX-A administration, elastic moduli were further decreased (p = 0.004) and distraction following TA BTX-A administration resulted in TA tendons with moduli not different from contralateral control (p > 0.05). Compared to contralateral control, distraction and GA BTX-A administration displayed shortened toe regions, (p = 0.031 and 0.038, respectively), while tendons receiving BTX-A in the TA had no differences in the toe region (p > 0.05). Ultimate tensile stress was unaltered by DO, but stress at the transition from the toe to the linear region of the stress-stretch curve was diminished in all distraction-elongated TA tendons (p < 0.05). The data suggest that prophylactic BTX-A treatment to the TA protects some tendon biomechanical properties. Copyright © 2010 Elsevier Ltd. All rights reserved.

Comparison of a novel bone-tendon allograft with a human dermis-derived patch for repair of chronic large rotator cuff tears using a canine model.

PubMed

Smith, Matthew J; Cook, James L; Kuroki, Keiichi; Jayabalan, Prakash S; Cook, Cristi R; Pfeiffer, Ferris M; Waters, Nicole P

2012-02-01

This study tested a bone-tendon allograft versus human dermis patch for reconstructing chronic rotator cuff repair by use of a canine model. Mature research dogs (N = 15) were used. Radiopaque wire was placed in the infraspinatus tendon (IST) before its transection. Three weeks later, radiographs showed IST retraction. Each dog then underwent 1 IST treatment: debridement (D), direct repair of IST to bone with a suture bridge and human dermis patch augmentation (GJ), or bone-tendon allograft (BT) reconstruction. Outcome measures included lameness grading, radiographs, and ultrasonographic assessment. Dogs were killed 6 months after surgery and both shoulders assessed biomechanically and histologically. BT dogs were significantly (P = .01) less lame than the other groups. BT dogs had superior bone-tendon, tendon, and tendon-muscle integrity compared with D and GJ dogs. Biomechanical testing showed that the D group had significantly (P = .05) more elongation than the other groups whereas BT had stiffness and elongation characteristics that most closely matched normal controls. Radiographically, D and GJ dogs showed significantly more retraction than BT dogs (P = .003 and P = .045, respectively) Histologically, GJ dogs had lymphoplasmacytic infiltrates, tendon degeneration and hypocellularity, and poor tendon-bone integration. BT dogs showed complete incorporation of allograft bone into host bone, normal bone-tendon junctions, and well-integrated allograft tendon. The bone-tendon allograft technique re-establishes a functional IST bone-tendon-muscle unit and maintains integrity of repair in this model. Clinical trials using this bone-tendon allograft technique are warranted. Copyright © 2012 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Functional tissue engineering of tendon: Establishing biological success criteria for improving tendon repair.

PubMed

Breidenbach, Andrew P; Gilday, Steven D; Lalley, Andrea L; Dyment, Nathaniel A; Gooch, Cynthia; Shearn, Jason T; Butler, David L

2014-06-27

Improving tendon repair using Functional Tissue Engineering (FTE) principles has been the focus of our laboratory over the last decade. Although our primary goals were initially focused only on mechanical outcomes, we are now carefully assessing the biological properties of our tissue-engineered tendon repairs so as to link biological influences with mechanics. However, given the complexities of tendon development and healing, it remains challenging to determine which aspects of tendon biology are the most important to focus on in the context of tissue engineering. To address this problem, we have formalized a strategy to identify, prioritize, and evaluate potential biological success criteria for tendon repair. We have defined numerous biological properties of normal tendon relative to cellular phenotype, extracellular matrix and tissue ultra-structure that we would like to reproduce in our tissue-engineered repairs and prioritized these biological criteria by examining their relative importance during both normal development and natural tendon healing. Here, we propose three specific biological criteria which we believe are essential for normal tendon function: (1) scleraxis-expressing cells; (2) well-organized and axially-aligned collagen fibrils having bimodal diameter distribution; and (3) a specialized tendon-to-bone insertion site. Moving forward, these biological success criteria will be used in conjunction with our already established mechanical success criteria to evaluate the effectiveness of our tissue-engineered tendon repairs. © 2013 Published by Elsevier Ltd.

The Quadriga Effect Revisited: Designing a “Safety Incision” to Prevent Tendon Repair Rupture and Gap Formation in a Canine Model In Vitro

PubMed Central

Giambini, Hugo; Ikeda, Jun; Amadio, Peter C.; An, Kai-Nan; Zhao, Chunfeng

2012-01-01

Loss of experimental animals due to tendon repair failure results in the need for additional animals to complete the study. We designed a relief proximal to the flexor digitorum profundus (FDP) tendon repair site to serve as a “safety incision” to prevent repair site ruptures and maximize safety incision-to-suture strength. The FDP tendons were dissected in 24 canine forepaws. The 2nd and 5th tendons were lacerated at the proximal interphalangeal joint level and sutured using a modified Kessler technique and peripheral running suture. Tendon width was measured where the FDP tendon separates into each individual digit and a safety incision, equal to the 2nd and 5th tendon widths, was performed 3, 4, or 5 mm (Groups 1, 2, and 3) proximal to the separation. The tendons were pulled at a rate of 1 mm/s until either the “safety incision” ruptured or the repair failed. There was no gap formation at the repair site in Groups 1 and 2. However, all Group 3 tendons failed by repair site rupture with the safety incision intact. An adequate safety incision to protect repair gap and rupture and maintain tendon tension for the FDP animal model should be about 4 mm from where the FDP tendon separates. PMID:20872585

Characterising the proximal patellar tendon attachment and its relationship to skeletal maturity in adolescent ballet dancers

PubMed Central

Rudavsky, Aliza; Cook, Jillianne; Magnusson, Stig Peter; Kjaer, Michael; Docking, Sean

2017-01-01

Summary Background It is unknown how and when the proximal attachment of the patellar tendon matures; puberty may be key in ensuring normal tendon formation. The aim of this study was to investigate the features of the proximal patellar tendon attachment at different stages of skeletal maturity, to help gain an understanding of how and when the tendon attachment matures. Methods Sixty adolescent elite ballet students (ages 11–18) and eight mature adults participated. Peak height velocity (PHV) estimated skeletal maturity. Ultrasound tissue characterisation (UTC) scan was taken of the left knee and analysed for stability of echopattern. An image-based grading scale for greyscale ultrasound was developed to describe the tendon appearance. Anterior-posterior thickness was measured at the inferior pole of the patella, 1 and 2 centimetres distally. Outcomes were compared with skeletal maturity. Results Mid-portion patellar tendon thickness increased with skeletal maturity (p=0.001 at 1 cm and p=0.007 at 2 cm). There was more variance in structural appearance (greyscale classification and UTC echopattern) in pre and peri-PHV participants. Tendon attachment one-year post PHV appeared similar to mature tendons. Conclusions Early adolescence was associated with highly variable tendon appearance, whereas the tendon appeared mature after PHV. Adolescence may be a critical time for the formation of normal tendon attachment. Level of evidence IIb individual cohort study. PMID:29264342

Biomechanical Cadaveric Evaluation of Partial Acute Peroneal Tendon Tears.

PubMed

Wagner, Emilio; Wagner, Pablo; Ortiz, Cristian; Radkievich, Ruben; Palma, Felipe; Guzmán-Venegas, Rodrigo

2018-06-01

No clear guideline or solid evidence exists for peroneal tendon tears to determine when to repair, resect, or perform a tenodesis on the damaged tendon. The objective of this study was to analyze the mechanical behavior of cadaveric peroneal tendons artificially damaged and tested in a cyclic and failure mode. The hypothesis was that no failure would be observed in the cyclic phase. Eight cadaveric long leg specimens were tested on a specially designed frame. A longitudinal full thickness tendon defect was created, 3 cm in length, behind the tip of the fibula, compromising 66% of the visible width of the peroneal tendons. Cyclic testing was initially performed between 50 and 200 N, followed by a load-to-failure test. Tendon elongation and load to rupture were measured. No tendon failed or lengthened during cyclic testing. The mean load to failure for peroneus brevis was 416 N (95% confidence interval, 351-481 N) and for the peroneus longus was 723 N (95% confidence interval, 578-868 N). All failures were at the level of the defect created. In a cadaveric model of peroneal tendon tears, 33% of remaining peroneal tendon could resist high tensile forces, above the physiologic threshold. Some peroneal tendon tears can be treated conservatively without risking spontaneous ruptures. When surgically treating a symptomatic peroneal tendon tear, increased efforts may be undertaken to repair tears previously considered irreparable.

Greater glycosaminoglycan content in human patellar tendon biopsies is associated with more pain and a lower VISA score.

PubMed

Attia, Mohamed; Scott, Alexander; Carpentier, Gilles; Lian, Oystein; Van Kuppevelt, Toin; Gossard, Camille; Papy-Garcia, Dulce; Tassoni, Marie-Claude; Martelly, Isabelle

2014-03-01

People with patellar tendinopathy experience chronic pain and activity limitation, but a pertinent biochemical marker correlated with these clinical features has not been identified. The Victoria Institute of Sport Assessment (VISA) questionnaire is a condition-specific patient-rated outcome measure. Since the quantity of glycosaminoglycans (GAGs) increases with advancing tendon pathology, we hypothesised that there would be a correlation between the quantity of GAGs in the patellar tendon and the VISA score. Tissue biopsies from athletes with chronic patellar tendinopathy (confirmed by clinical examination and MRI) were recruited (n=7), as well as controls with no history of knee pain (n=4). The quantity of sulphated GAGs in the human patellar tendons was determined with a dimethyl methylene blue (DMMB) assay; this method was first validated with rat tendon tissue. The extent and distribution of GAG species and proteoglycans (decorin, versican and aggrecan) in the human tendon biopsies were examined using immunohistochemistry. Greater sulphated GAG content of the patellar tendon was correlated with the greater tendon dysfunction (R(2)=0.798). The quantity of aggrecan in the tendon, a chondroitin sulphate-rich proteoglycan, also increased with advancing tendon pathology. Increased GAGs in the pathological human patellar tendon are related to a worse clinical status. These findings indicate that the VISA score reflects the extent of tendon tissue pathology.

Central Tendon Injuries of Hamstring Muscles: Case Series of Operative Treatment

PubMed Central

Lempainen, Lasse; Kosola, Jussi; Pruna, Ricard; Puigdellivol, Jordi; Sarimo, Janne; Niemi, Pekka; Orava, Sakari

2018-01-01

Background: As compared with injuries involving muscle only, those involving the central hamstring tendon have a worse prognosis. Limited information is available regarding the surgical treatment of central tendon injuries of the hamstrings. Purpose: To describe the operative treatment and outcomes of central tendon injuries of the hamstrings among athletes. Study Design: Case series; Level of evidence, 4. Methods: Eight athletes (6 top level, 2 recreational) with central hamstring tendon injuries underwent magnetic resonance imaging and surgical treatment. The indication for surgery was recurrent (n = 6) or acute (n = 2) central hamstring tendon injury. All patients followed the same postoperative rehabilitation protocol, and return to play was monitored. Results: Magnetic resonance imaging found a central tendon injury in all 3 hamstring muscles (long head of the biceps femoris, semimembranosus, and semitendinosus) with disrupted tendon ends. In acute and recurrent central tendon injuries, full return to play was achieved at 2.5 to 4 months. There were no adverse events during follow-up. Conclusion: Central tendon injuries of the hamstrings can be successfully repaired surgically after acute and recurrent ruptures. PMID:29479545

Bioreactor design for tendon/ligament engineering.

PubMed

Wang, Tao; Gardiner, Bruce S; Lin, Zhen; Rubenson, Jonas; Kirk, Thomas B; Wang, Allan; Xu, Jiake; Smith, David W; Lloyd, David G; Zheng, Ming H

2013-04-01

Tendon and ligament injury is a worldwide health problem, but the treatment options remain limited. Tendon and ligament engineering might provide an alternative tissue source for the surgical replacement of injured tendon. A bioreactor provides a controllable environment enabling the systematic study of specific biological, biochemical, and biomechanical requirements to design and manufacture engineered tendon/ligament tissue. Furthermore, the tendon/ligament bioreactor system can provide a suitable culture environment, which mimics the dynamics of the in vivo environment for tendon/ligament maturation. For clinical settings, bioreactors also have the advantages of less-contamination risk, high reproducibility of cell propagation by minimizing manual operation, and a consistent end product. In this review, we identify the key components, design preferences, and criteria that are required for the development of an ideal bioreactor for engineering tendons and ligaments.

Bioreactor Design for Tendon/Ligament Engineering

PubMed Central

Wang, Tao; Gardiner, Bruce S.; Lin, Zhen; Rubenson, Jonas; Kirk, Thomas B.; Wang, Allan; Xu, Jiake

2013-01-01

Tendon and ligament injury is a worldwide health problem, but the treatment options remain limited. Tendon and ligament engineering might provide an alternative tissue source for the surgical replacement of injured tendon. A bioreactor provides a controllable environment enabling the systematic study of specific biological, biochemical, and biomechanical requirements to design and manufacture engineered tendon/ligament tissue. Furthermore, the tendon/ligament bioreactor system can provide a suitable culture environment, which mimics the dynamics of the in vivo environment for tendon/ligament maturation. For clinical settings, bioreactors also have the advantages of less-contamination risk, high reproducibility of cell propagation by minimizing manual operation, and a consistent end product. In this review, we identify the key components, design preferences, and criteria that are required for the development of an ideal bioreactor for engineering tendons and ligaments. PMID:23072472

The prevalence and clinical significance of sonographic tendon abnormalities in asymptomatic ballet dancers: a 24-month longitudinal study.

PubMed

Comin, Jules; Cook, Jill L; Malliaras, Peter; McCormack, Moira; Calleja, Michelle; Clarke, Andrew; Connell, David

2013-01-01

Sonographic abnormalities of the achilles and patellar tendons are common findings in athletes, and tendinopathy is a common cause of pain and disability in athletes. However, it is unclear whether the sonographic changes are pathological or adaptive, or if they predict future injury. We undertook a cohort study to determine what sonographic features of the achilles and patellar tendons are consistent with changes as a result of ballet training, and which may be predictive of future development of disabling tendon symptoms. The achilles and patellar tendons of 79 (35 male, 44 female) professional ballet dancers (members of the English Royal Ballet) were examined with ultrasound, measuring proximal and distal tendon diameters and assessing for the presence of hypoechoic change, intratendon defects, calcification and neovascularity. All subjects were followed for 24 months for the development of patellar tendon or achilles-related pain or injury severe enough to require time off from dancing. Sonographic abnormalities were common among dancers, both male and female, and in both achilles and patellar tendons. Disabling tendon-related symptoms developed in 10 dancers and 14 tendons: 7 achilles (3 right, 4 left) and 7 patellar (2 right, 5 left). The presence of moderate or severe hypoechoic defects was weakly predictive for the development of future disabling tendon symptoms (p=0.0381); there was no correlation between any of the other sonographic abnormalities and the development of symptoms. There was no relationship between achilles or patellar tendons' diameter, either proximal or distal, with an increased likelihood of developing tendon-related disability. The presence of sonographic abnormalities is common in ballet dancers, but only the presence of focal hypoechoic changes predicts the development of future tendon-related disability. This suggests that screening of asymptomatic individuals may be of use in identifying those who are at higher risk of developing tendon-related disability, which may in turn allow targeted modifications of training or other preventative regimens.

Optimization of human tendon tissue engineering: peracetic acid oxidation for enhanced reseeding of acellularized intrasynovial tendon.

PubMed

Woon, Colin Y L; Pridgen, Brian C; Kraus, Armin; Bari, Sina; Pham, Hung; Chang, James

2011-03-01

Tissue engineering of human flexor tendons combines tendon scaffolds with recipient cells to create complete cell-tendon constructs. Allogenic acellularized human flexor tendon has been shown to be a useful natural scaffold. However, there is difficulty repopulating acellularized tendon with recipient cells, as cell penetration is restricted by a tightly woven tendon matrix. The authors evaluated peracetic acid treatment in optimizing intratendinous cell penetration. Cadaveric human flexor tendons were harvested, acellularized, and divided into experimental groups. These groups were treated with peracetic acid in varying concentrations (2%, 5%, and 10%) and for varying time periods (4 and 20 hours) to determine the optimal treatment protocol. Experimental tendons were analyzed for differences in tendon microarchitecture. Additional specimens were reseeded by incubation in a fibroblast cell suspension at 1 × 10(6) cells/ml. This group was then analyzed for reseeding efficacy. A final group underwent biomechanical studies for strength. The optimal treatment protocol comprising peracetic acid at 5% concentration for 4 hours produced increased scaffold porosity, improving cell penetration and migration. Treated scaffolds did not show reduced collagen or glycosaminoglycan content compared with controls (p = 0.37 and p = 0.65, respectively). Treated scaffolds were cytotoxic to neither attached cells nor the surrounding cell suspension. Treated scaffolds also did not show inferior ultimate tensile stress or elastic modulus compared with controls (p = 0.26 and p = 0.28, respectively). Peracetic acid treatment of acellularized tendon scaffolds increases matrix porosity, leading to greater reseeding. It may prove to be an important step in tissue engineering of human flexor tendon using natural scaffolds.

Effects of Increased Loading on In Vivo Tendon Properties: A Systematic Review

PubMed Central

WIESINGER, HANS-PETER; KÖSTERS, ALEXANDER; MÜLLER, ERICH; SEYNNES, OLIVIER R.

2015-01-01

ABSTRACT Introduction In vivo measurements have been used in the past two decades to investigate the effects of increased loading on tendon properties, yet the current understanding of tendon macroscopic changes to training is rather fragmented, limited to reports of tendon stiffening, supported by changes in material properties and/or tendon hypertrophy. The main aim of this review was to analyze the existing literature to gain further insights into tendon adaptations by extracting patterns of dose-response and time-course. Methods PubMed/Medline, SPORTDiscus, and Google Scholar databases were searched for studies examining the effect of training on material, mechanical, and morphological properties via longitudinal or cross-sectional designs. Results Thirty-five of 6440 peer-reviewed articles met the inclusion criteria. The key findings were i) the confirmation of a nearly systematic adaptation of tendon tissue to training, ii) the important variability in the observed changes in tendon properties between and within studies, and iii) the absence of a consistent incremental pattern regarding the dose-response or the time-course relation of tendon adaptation within the first months of training. However, long-term (years) training was associated with a larger tendon cross-sectional area, without any evidence of differences in material properties. Our analysis also highlighted several gaps in the existing literature, which may be addressed in future research. Conclusions In line with some cross-species observations about tendon design, tendon cross-sectional area allegedly constitutes the ultimate adjusting parameter to increased loading. We propose here a theoretical model placing tendon hypertrophy and adjustments in material properties as parts of the same adaptive continuum. PMID:25563908

Continuous Shear Wave Elastography: A New Method to Measure Viscoelastic Properties of Tendons in Vivo.

PubMed

Cortes, Daniel H; Suydam, Stephen M; Silbernagel, Karin Grävare; Buchanan, Thomas S; Elliott, Dawn M

2015-06-01

Viscoelastic mechanical properties are frequently altered after tendon injuries and during recovery. Therefore, non-invasive measurements of shear viscoelastic properties may help evaluate tendon recovery and compare the effectiveness of different therapies. The objectives of this study were to describe an elastography method for measuring localized viscoelastic properties of tendons and to discuss the initial results in healthy and injured human Achilles and semitendinosus tendons. The technique used an external actuator to generate the shear waves in the tendon at different frequencies and plane wave imaging to measure shear wave displacements. For each of the excitation frequencies, maps of direction-specific wave speeds were calculated using local frequency estimation. Maps of viscoelastic properties were obtained using a pixel-wise curve fit of wave speed and frequency. The method was validated by comparing measurements of wave speed in agarose gels with those obtained using magnetic resonance elastography. Measurements in human healthy Achilles tendons revealed a pronounced increase in wave speed as a function of frequency, which highlights the importance of tendon viscoelasticity. Additionally, the viscoelastic properties of the Achilles tendon were larger than those reported for other tissues. Measurements in a tendinopathic Achilles tendon indicated that it is feasible to quantify local viscoelastic properties. Similarly, measurement in the semitendinosus tendon revealed substantial differences in viscoelastic properties between the healthy and contralateral tendons. Consequently, this technique has the potential to evaluate localized changes in tendon viscoelastic properties caused by injury and during recovery in a clinical setting. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

How does a cadaver model work for testing ultrasound diagnostic capability for rheumatic-like tendon damage?

PubMed

Janta, Iustina; Morán, Julio; Naredo, Esperanza; Nieto, Juan Carlos; Uson, Jacqueline; Möller, Ingrid; Bong, David; Bruyn, George A W; D Agostino, Maria Antonietta; Filippucci, Emilio; Hammer, Hilde Berner; Iagnocco, Annamaria; Terslev, Lene; González, Jorge Murillo; Mérida, José Ramón; Carreño, Luis

2016-06-01

To establish whether a cadaver model can serve as an effective surrogate for the detection of tendon damage characteristic of rheumatoid arthritis (RA). In addition, we evaluated intraobserver and interobserver agreement in the grading of RA-like tendon tears shown by US, as well as the concordance between the US findings and the surgically induced lesions in the cadaver model. RA-like tendon damage was surgically induced in the tibialis anterior tendon (TAT) and tibialis posterior tendon (TPT) of ten ankle/foot fresh-frozen cadaveric specimens. Of the 20 tendons examined, six were randomly assigned a surgically induced partial tear; six a complete tear; and eight left undamaged. Three rheumatologists, experts in musculoskeletal US, assessed from 1 to 5 the quality of US imaging of the cadaveric models on a Likert scale. Tendons were then categorized as having either no damage, (0); partial tear, (1); or complete tear (2). All 20 tendons were blindly and independently evaluated twice, over two rounds, by each of the three observers. Overall, technical performance was satisfactory for all items in the two rounds (all values over 2.9 in a Likert scale 1-5). Intraobserver and interobserver agreement for US grading of tendon damage was good (mean κ values 0.62 and 0.71, respectively), with greater reliability found in the TAT than the TPT. Concordance between US findings and experimental tendon lesions was acceptable (70-100 %), again greater for the TAT than for the TPT. A cadaver model with surgically created tendon damage can be useful in evaluating US metric properties of RA tendon lesions.

Decellularized Tendon Extracellular Matrix—A Valuable Approach for Tendon Reconstruction?

PubMed Central

Schulze-Tanzil, Gundula; Al-Sadi, Onays; Ertel, Wolfgang; Lohan, Anke

2012-01-01

Tendon healing is generally a time-consuming process and often leads to a functionally altered reparative tissue. Using degradable scaffolds for tendon reconstruction still remains a compromise in view of the required high mechanical strength of tendons. Regenerative approaches based on natural decellularized allo- or xenogenic tendon extracellular matrix (ECM) have recently started to attract interest. This ECM combines the advantages of its intrinsic mechanical competence with that of providing tenogenic stimuli for immigrating cells mediated, for example, by the growth factors and other mediators entrapped within the natural ECM. A major restriction for their therapeutic application is the mainly cell-associated immunogenicity of xenogenic or allogenic tissues and, in the case of allogenic tissues, also the risk of disease transmission. A survey of approaches for tendon reconstruction using cell-free tendon ECM is presented here, whereby the problems associated with the decellularization procedures, the success of various recellularization strategies, and the applicable cell types will be thoroughly discussed. Encouraging in vivo results using cell-free ECM, as, for instance, in rabbit models, have already been reported. However, in comparison to native tendon, cells remain mostly inhomogeneously distributed in the reseeded ECM and do not align. Hence, future work should focus on the optimization of tendon ECM decellularization and recolonization strategies to restore tendon functionality. PMID:24710540

Achilles tendons from decorin- and biglycan-null mouse models have inferior mechanical and structural properties predicted by an image-based empirical damage model

PubMed Central

Gordon, J.A.; Freedman, B.R.; Zuskov, A.; Iozzo, R.V.; Birk, D.E.; Soslowsky, L.J.

2015-01-01

Achilles tendons are a common source of pain and injury, and their pathology may originate from aberrant structure function relationships. Small leucine rich proteoglycans (SLRPs) influence mechanical and structural properties in a tendon-specific manner. However, their roles in the Achilles tendon have not been defined. The objective of this study was to evaluate the mechanical and structural differences observed in mouse Achilles tendons lacking class I SLRPs; either decorin or biglycan. In addition, empirical modeling techniques based on mechanical and image-based measures were employed. Achilles tendons from decorin-null (Dcn−/−) and biglycan-null (Bgn−/−) C57BL/6 female mice (N=102) were used. Each tendon underwent a dynamic mechanical testing protocol including simultaneous polarized light image capture to evaluate both structural and mechanical properties of each Achilles tendon. An empirical damage model was adapted for application to genetic variation and for use with image based structural properties to predict tendon dynamic mechanical properties. We found that Achilles tendons lacking decorin and biglycan had inferior mechanical and structural properties that were age dependent; and that simple empirical models, based on previously described damage models, were predictive of Achilles tendon dynamic modulus in both decorin- and biglycan-null mice. PMID:25888014

Achilles tendons from decorin- and biglycan-null mouse models have inferior mechanical and structural properties predicted by an image-based empirical damage model.

PubMed

Gordon, J A; Freedman, B R; Zuskov, A; Iozzo, R V; Birk, D E; Soslowsky, L J

2015-07-16

Achilles tendons are a common source of pain and injury, and their pathology may originate from aberrant structure function relationships. Small leucine rich proteoglycans (SLRPs) influence mechanical and structural properties in a tendon-specific manner. However, their roles in the Achilles tendon have not been defined. The objective of this study was to evaluate the mechanical and structural differences observed in mouse Achilles tendons lacking class I SLRPs; either decorin or biglycan. In addition, empirical modeling techniques based on mechanical and image-based measures were employed. Achilles tendons from decorin-null (Dcn(-/-)) and biglycan-null (Bgn(-/-)) C57BL/6 female mice (N=102) were used. Each tendon underwent a dynamic mechanical testing protocol including simultaneous polarized light image capture to evaluate both structural and mechanical properties of each Achilles tendon. An empirical damage model was adapted for application to genetic variation and for use with image based structural properties to predict tendon dynamic mechanical properties. We found that Achilles tendons lacking decorin and biglycan had inferior mechanical and structural properties that were age dependent; and that simple empirical models, based on previously described damage models, were predictive of Achilles tendon dynamic modulus in both decorin- and biglycan-null mice. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Rheumatic tendon pathologies].

PubMed

Thomas, M; Jordan, M

2014-11-01

Rheumatoid arthritis is found in approximately 2 % of the total population in Europe and the peak incidence of the disease is during the fourth and fifth decades of life. In approximately 15 % the first symptoms of the disease occur at the level of the foot and ankle. If the early stage-dependent therapy with pharmaceuticals fails isolated surgery of the tendons (e.g. tenosynovectomy) and reconstructive surgery including the tendons (e.g. tendon transfer and tendon readaptation) are performed to keep the patient mobile. The aim of this article is to give an overview of the most commonly used interventions in the reconstruction of tendons in rheumatism patients and the corresponding indications. The conservative therapy options for rheumatic foot and ankle alterations with a special emphasis on tendon pathologies have a well-established importance and are also presented. A selective literature search was carried out for therapeutic options of rheumatic tendon pathologies. If possible attempts should be made to preserve functional qualities using tenosynovectomy, tendon sutures or tendon transfer operations. If joints are already destroyed or dislocated, tendon operations should be carried out only as combined interventions with arthrodesis, endoprostheses or resection arthroplasty. The time window in which these interventions are possible should not be missed. Orthotic devices, bandages or even orthopedic shoes provide external support and splinting but do not represent a causal therapy.

Magnetotherapy: The quest for tendon regeneration.

PubMed

Pesqueira, Tamagno; Costa-Almeida, Raquel; Gomes, Manuela E

2018-05-09

Tendons are mechanosensitive tissues that connect and transmit the forces generated by muscles to bones by allowing the conversion of mechanical input into biochemical signals. These physical forces perform the fundamental work of preserving tendon homeostasis assuring body movements. However, overloading causes tissue injuries, which leads us to the field of tendon regeneration. Recently published reviews have broadly shown the use of biomaterials and different strategies to attain tendon regeneration. In this review, our focus is the use of magnetic fields as an alternative therapy, which has demonstrated clinical relevance in tendon medicine because of their ability to modulate cell fate. Yet the underlying cellular and molecular mechanisms still need to be elucidated. While providing a brief outlook about specific signalling pathways and intracellular messengers as framework in play by tendon cells, application of magnetic fields as a subcategory of physical forces is explored, opening up a compelling avenue to enhance tendon regeneration. We outline here useful insights on the effects of magnetic fields both at in vitro and in vivo levels, particularly on the expression of tendon genes and inflammatory cytokines, ultimately involved in tendon regeneration. Subsequently, the potential of using magnetically responsive biomaterials in tendon tissue engineering is highlighted and future directions in magnetotherapy are discussed. © 2018 Wiley Periodicals, Inc.

Mechanical Strength of the Side-to-Side Tendon Attachment for Mismatched Tendon Sizes and Shapes

PubMed Central

Fridén, Jan; Tirrell, Timothy F.; Bhola, Siddharth; Lieber, Richard L.

2015-01-01

Summary Certain combinations are advised against in tendon transfers due to size or shape mismatches between donor and recipient tendons. In this study, ultimate load, stiffness and Young’s modulus were measured in two tendon-to-tendon attachments with intentionally mismatched donor and recipient tendons - pronator teres (PT)-to-extensor carpi radialis brevis (ECRB) and flexor carpi ulnaris (FCU)-to-extensor digitorum communis (EDC). FCU-EDC attachments failed at higher loads than PT-to-ECRB attachments but they had similar modulus and stiffness values. Ultimate tensile strength of the tendon attachments exceeded the maximum predicted contraction force of any of the affected muscles, with safety factors of 4x and 2x for the FCU-to-EDC and PT-to-ECRB constructs, respectively. This implies that size and shape mismatch should not be a contraindication to tendon attachment in transfers. Further, these safety factors strongly suggest that no postoperative immobilization of these attachments is necessary. PMID:24413573

Stem cell technology for tendon regeneration: current status, challenges, and future research directions

PubMed Central

Lui, Pauline Po Yee

2015-01-01

Tendon injuries are a common cause of physical disability. They present a clinical challenge to orthopedic surgeons because injured tendons respond poorly to current treatments without tissue regeneration and the time required for rehabilitation is long. New treatment options are required. Stem cell-based therapies offer great potential to promote tendon regeneration due to their high proliferative, synthetic, and immunomodulatory activities as well as their potential to differentiate to the target cell types and undergo genetic modification. In this review, I first recapped the challenges of tendon repair by reviewing the anatomy of tendon. Next, I discussed the advantages and limitations of using different types of stem cells compared to terminally differentiated cells for tendon tissue engineering. The safety and efficacy of application of stem cells and their modified counterparts for tendon tissue engineering were then summarized after a systematic literature search in PubMed. The challenges and future research directions to enhance, optimize, and standardize stem cell-based therapies for augmenting tendon repair were then discussed. PMID:26715856

[Rupture of the Achilles tendon].

PubMed

Ulmar, B; Simon, S; Eschler, A; Mittlmeier, T

2014-10-01

The rupture of the Achilles tendon is the most frequent tendon rupture in humans and it is associated with increasing incidence. The main risk factor is intrinsic degeneration of the tendon. During the rupture the person feels a whiplash or dagger thrust-like pain, followed by restricted walking ability and decreased plantar flexion of the ankle. The positive Simmond/Thompson test and a palpable dent above the tendon rupture are pathognomical. Diagnostically, ultrasound of the tendon and lateral x-ray of the calcaneus (bony pull-out of the tendon insertion) are necessary. Regarding correct indication and treatment modalities, most established conservative and surgical therapies realize optimal functional results. Surgical treatment promises better primary stability and slightly earlier better functional results, but there is the potential for surgical complications. Conservative therapy is associated with higher rates of re-rupture and healing of the tendon under elongation. Therefore, therapy planning in Achilles tendon rupture should be determined based on each patient. We recommend surgical treatment in patients with higher sporting demands and in younger patients (< 50 years).

Experimental study of the effects of helium-neon laser radiation on repair of injured tendon

NASA Astrophysics Data System (ADS)

Xu, Yong-Qing; Li, Zhu-Yi; Weng, Long-Jiang; An, Mei; Li, Kai-Yun; Chen, Shao-Rong; Wang, Jian-Xin; Lu, Yu

1993-03-01

Despite extensive research into the biology of tendon healing, predictably restoring normal function to a digit after a flexor tendon laceration remains one of the most difficult problems facing the hand surgeon. The challenge of simultaneously achieving tendon healing while minimizing the peritendinous scar formation, which limits tendon gliding, has captured the attention of investigators for many years. It has been said that low-power density helium-neon laser radiation had effects on anti-inflammation, detumescence, progressive wound healing, and reducing intestinal adhesions. This experimental study aims at whether helium-neon laser can reduce injured tendon adhesions and improve functional recovery of the injured tendon. Fifty white Leghorn hens were used. Ten were randomly assigned as a normal control group, the other forty were used in the operation. After anesthetizing them with Amytal, a half of the profundus tendons of the second and third foretoes on both sides of the feet were cut. Postoperatively, the hens moved freely in the cages. One side of the toes operated on were randomly chosen as a treatment group, the other side served as an untreated control group. The injured tendon toes in the treatment group were irradiated for twenty minutes daily with a fiber light needle of helium-neon laser therapeutic apparatus (wavelength, 6328 angstroms) at a constant power density of 12.74 mW/cm2, the first exposure taking place 24 hours after the operation. The longest course of treatment was 3 weeks. The control group was not irradiated. At 3 days, 1, 2, 3, and 5 weeks after surgery, 8 hens were sacrificed and their tendons were examined. The experimental results: (1) active, passive flexion and tendon gliding functional recovery were significantly better in the treatment group (p < 0.01); (2) width and thickness of the tendon at the cut site were significantly smaller in the treatment group (p < 0.01); (3) degrees of tendon adhesions were significantly lighter in the treatment group (p < 0.05). The experimental results demonstrate helium-neon laser radiation had significant effects on anti-inflammation, detumescence, progressive hematoma absorbing, inhibiting the tendon extrinsic healing, reducing tendon adhesions, improving the tendon intrinsic healing, i.e., stimulating epitenon and endotenon cells proliferation and migrating into the gap, stimulating collagen synthesis in the tendon gap, and enhancing the late remodeling of fibrous peritendonous adhesion.

Management of acute Achilles tendon rupture with tendon-bundle technique

PubMed Central

Li, Chun-Guang; Li, Bing

2017-01-01

Objective *These authors contributed equally to this work.To explore tendon-bundle technique for treating Achilles tendon rupture with no defects. Methods Patients with full unilateral Achilles tendon rupture with no defects were included. The Achilles tendon medial edge surgical repair approach was used, revealing horsetail-like rupture bundles. Tendon bundles were anatomically realigned and repaired end-to-end using 5-0 sutures. Patients were followed-up for 1 year, and assessed for differences between the repaired versus healthy limb. Results Out of 24 patients (18 male, 6 female; aged 19–56 years) at 1 year following surgery, mean American Orthopaedic Foot and Ankle Society score was 92.4 ± 5.9; mean differences between the surgically repaired versus contralateral side in dorsiflexion and plantarflexion angle were 3.5 ± 2.3° and 5.6 ± 3.2°, respectively; mean difference in calf circumference between the two sides was 0.9 ± 0.5 cm; and mean increase in Achilles tendon width versus the healthy side was 0.8 ± 0.2 cm. By 1 year post-surgery, there were no significant between-side differences in dorsiflexion and plantarflexion angle, or calf circumference. Conclusions Tendon-bundle surgery resulted in good ankle function restoration and low complication rates. Tendon-bundle surgery may reduce blood supply destruction and maximally preserve Achilles tendon length, and may be effective for treating Achilles tendon rupture with no defects. PMID:28222622

Proteomic Analysis Reveals Age-related Changes in Tendon Matrix Composition, with Age- and Injury-specific Matrix Fragmentation*

PubMed Central

Peffers, Mandy J.; Thorpe, Chavaunne T.; Collins, John A.; Eong, Robin; Wei, Timothy K. J.; Screen, Hazel R. C.; Clegg, Peter D.

2014-01-01

Energy storing tendons, such as the human Achilles and equine superficial digital flexor tendon (SDFT), are highly prone to injury, the incidence of which increases with aging. The cellular and molecular mechanisms that result in increased injury in aged tendons are not well established but are thought to result in altered matrix turnover. However, little attempt has been made to fully characterize the tendon proteome nor determine how the abundance of specific tendon proteins changes with aging and/or injury. The aim of this study was, therefore, to assess the protein profile of normal SDFTs from young and old horses using label-free relative quantification to identify differentially abundant proteins and peptide fragments between age groups. The protein profile of injured SDFTs from young and old horses was also assessed. The results demonstrate distinct proteomic profiles in young and old tendon, with alterations in the levels of proteins involved in matrix organization and regulation of cell tension. Furthermore, we identified several new peptide fragments (neopeptides) present in aged tendons, suggesting that there are age-specific cleavage patterns within the SDFT. Proteomic profile also differed between young and old injured tendon, with a greater number of neopeptides identified in young injured tendon. This study has increased the knowledge of molecular events associated with tendon aging and injury, suggesting that maintenance and repair of tendon tissue may be reduced in aged individuals and may help to explain why the risk of injury increases with aging. PMID:25077967

Fibrocartilage associated with human tendons and their pulleys.

PubMed Central

Benjamin, M; Qin, S; Ralphs, J R

1995-01-01

The presence of fibrocartilage in tendons that wrap around bony or fibrous pulleys is well known. It is an adaptation to resisting compression or shear, but the extent to which the structure of most human tendons is modified where they contact pulleys is less clear, for there has been no single comprehensive survey of a large number of sites. Less is known of the structure of the corresponding pulleys. In the present study, 38 regions of tendons that wrap around bony pulleys or pass beneath fibrous retinacula have been studied in routine histology sections taken from each of 2 or 3 elderly dissecting room cadavers. Most of the corresponding pulleys have also been examined. Fibrocartilage was present in 22 of the 38 tendon sites and it was most conspicuous where the tendons pressed predominantly against bone rather than retinacula and where they showed a large change in direction. Fibrocartilage was more characteristic of tendons at the ankle than the wrist, probably because the long axis of the foot is at right angles to that of the leg. There was considerable variation in the structure of tendon fibrocartilage. The most fibrocartilaginous tendons had oval or round cells embedded in a highly metachromatic matrix with interwoven or spiralling collagen fibres. At other sites, fibrocartilage cells were arranged in rows between parallel collagen fibres. The differences probably relate to differences in development. A single tendon could be modified at successive points along its length and fibrocartilage could be present in the endotenon and epitenon as well as in the tendon itself. Pathological changes seen in 'wrap around' tendons were fragmentation and partial delamination of the compressed surface, chondrocyte clustering, fatty infiltration and bone formation. Three types of pulleys were described for tendons--bony prominences and grooves, fibrous retinacula and synovial joints. The extent of cartilaginous differentiation on the periosteum of bony pulleys frequently mirrored that in the corresponding tendon. The cartilage or fibrocartilage prevents the tendon from 'sawing' through the bone. Some of the best known retinacula were largely fibrous, though the inferior peroneal retinaculum and the trochlea for the superior oblique were cartilaginous. The results underline the considerable regional heterogeneity in different tendons and their pulleys. They show that one tendon is not like another and that tendons may need to be carefully selected for particular surgical transfers or joint reconstructions. Images Fig. 1 Figs 2-3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 11 Fig. 12 Fig. 13 Fig. 14 Fig. 15 Fig. 16 Fig. 17 Fig. 18 PMID:8586561

Tendon elasticity and muscle function.

PubMed

Alexander, R McNeill

2002-12-01

Vertebrate animals exploit the elastic properties of their tendons in several different ways. Firstly, metabolic energy can be saved in locomotion if tendons stretch and then recoil, storing and returning elastic strain energy, as the animal loses and regains kinetic energy. Leg tendons save energy in this way when birds and mammals run, and an aponeurosis in the back is also important in galloping mammals. Tendons may have similar energy-saving roles in other modes of locomotion, for example in cetacean swimming. Secondly, tendons can recoil elastically much faster than muscles can shorten, enabling animals to jump further than they otherwise could. Thirdly, tendon elasticity affects the control of muscles, enhancing force control at the expense of position control.

The Achilles tendon: fundamental properties and mechanisms governing healing

PubMed Central

Freedman, Benjamin R.; Gordon, Joshua A.; Soslowsky, Louis J.

2014-01-01

Summary This review highlights recent research on Achilles tendon healing, and comments on the current clinical controversy surrounding the diagnosis and treatment of injury. The processes of Achilles tendon healing, as demonstrated through changes in its structure, composition, and biomechanics, are reviewed. Finally, a review of tendon developmental biology and mechano transductive pathways is completed to recognize recent efforts to augment injured Achilles tendons, and to suggest potential future strategies for therapeutic intervention and functional tissue engineering. Despite an abundance of clinical evidence suggesting that current treatments and rehabilitation strategies for Achilles tendon ruptures are equivocal, significant questions remain to fully elucidate the basic science mechanisms governing Achilles tendon injury, healing, treatment, and rehabilitation. PMID:25332943

The role of ultrasound in the management of flexor tendon injuries.

PubMed

Jeyapalan, K; Bisson, M A; Dias, J J; Griffin, Y; Bhatt, R

2008-08-01

The use of ultrasound scanning to establish tendon pathologies was assessed retrospectively in 17 patients in 18 digits. The ultrasound scan demonstrated four patterns: (1) normal intact tendons in four, (2) ruptured tendons in three, (3) tendons in continuity but attenuated in five and (4) tendons in continuity but thickened with fibrosis and decreased movement representing adhesions in five patients. Surgery was undertaken in only three cases, confirming the ultrasound diagnosis in two. Surgery was offered to all three patients with ruptures but was declined by two. Ultrasound imaging helped to avoid surgery in 14 cases by excluding flexor tendon re-ruptures. This allowed on-going mobilisation, leading to recovery of function.

Distal Biceps Tendon Rupture

DTIC Science & Technology

2010-06-01

Distal Biceps Tendon Rupture Military Medicine Radiology Corner, 2006 Radiology Corner Distal Biceps Tendon Rupture Contributors: CPT Michael...treatment of a 56-year-old man with complete rupture of the distal biceps tendon . The mechanism of injury, symptoms, and findings at physical...be used in pre-operative planning. Introduction Rupture of the distal biceps tendon is a relatively uncommon injury, but delayed diagnosis may

A Multi-modality Approach Towards Elucidation of the Mechanism for Human Achilles Tendon Bending During Passive Ankle Rotation.

PubMed

Kinugasa, Ryuta; Taniguchi, Keigo; Yamamura, Naoto; Fujimiya, Mineko; Katayose, Masaki; Takagi, Shu; Edgerton, V Reggie; Sinha, Shantanu

2018-03-12

The in vitro unconstrained Achilles tendon is nearly straight, while in vivo experiments reveal that the proximal region of the Achilles tendon, adjacent to Kager's fat pad, bends ventrally during plantarflexion but remains nearly straight during dorsiflexion. Tendon bending is an important factor in determining the displacement of the foot compared to the shortening of the muscle fibers. The objective of this study was to elucidate the various mechanisms that could cause tendon bending, which currently remain unknown. Examination of Thiel-embalmed cadavers, with preservation of native articular joint mobility, revealed that the Achilles tendon still bent ventrally even when its surrounding tissues, including the skin surface, Kager's fat pad, and distal portions of the soleus muscle were removed. Shear modulus and collagen fiber orientation were distributed homogeneously with respect to the longitudinal line of the tendon, minimizing their causative contributions to the bending. Given that tendon bending is not caused by either the nature of the deformations of the tissues surrounding the Achilles tendon or its physical properties, we conclude that it results from the geometric architecture of the Achilles tendon and its configuration with respect to the surrounding tissues.

Tensile properties of craniofacial tendons in the mature and aged zebrafish

PubMed Central

Shah, Rishita R.; Nerurkar, Nandan L.; Wang, Calvin; Galloway, Jenna L.

2015-01-01

The zebrafish Danio rerio is a powerful model for the study of development, regenerative biology, and human disease. However, the analysis of load-bearing tissues such as tendons and ligaments has been limited in this system. This is largely due to technical limitations that preclude accurate measurement of their mechanical properties. Here, we present a custom tensile testing system that applies nano-Newton scale forces to zebrafish tendons as small as 1 mm in length. Tendon properties were remarkably similar to mammalian tendons, including stress-strain nonlinearity and a linear modulus (515±152 MPa) that aligned closely with mammalian data. Additionally, a simple exponential constitutive law used to describe tendon mechanics was successfully fit to zebrafish tendons; the associated material constants agreed with literature values for mammalian tendons. Finally, mature and aged zebrafish comparisons revealed a significant decline in mechanical function with age. Based on the exponential constitutive model, age related changes were primarily caused by a reduction in nonlinearity (e.g. changes in collagen crimp or fiber recruitment). These findings demonstrate the utility of zebrafish as a model to study tendon biomechanics in health and disease. Moreover, these findings suggest that tendon mechanical behavior is highly conserved across vertebrates. PMID:25665155

Effects of habitual loading on patellar tendon mechanical and morphological properties in basketball and volleyball players.

PubMed

Zhang, Z J; Ng, G Y F; Fu, S N

2015-11-01

Tendon mechanical properties are linked to sports performance and tendon-related injuries, such as tendinopathy. Whether habitual loading, such as participation in regular jumping activities, would induce adaptation on tendon mechanical properties remains unclear. Forty healthy subjects (10 sedentary, 15 volleyball players, and 15 basketball players) aged between 18 and 35 years were recruited. Supersonic shearwave imaging was used to measure the shear elastic modulus and thickness and cross-sectional area (CSA) of the proximal patellar tendons of both knees at 30° of flexion. Significant group differences in tendon shear elastic modulus were found among the three groups. In the dominant leg, reduction in tendon shear elastic modulus by 18.9 % (p = 0.018) and 48.7 % (p = 0.000) were observed in the basketball and volleyball players, respectively, when compared with sedentary subjects. In the non-dominant leg, reduction in tendon shear elastic modulus were 27.3 % (p = 0.034) and 47.1 % (p = 0.02) in the basketball and volleyball players, respectively. The athlete groups were found to have larger CSA but with similar tendon thickness than sedentary group. The CSA were larger by 24-29 % and by 22-24 % in the basketball players and volleyball players, for the dominant and non-dominant legs, respectively (all p < 0.05). Age and body mass are related to tendon stiffness and CSA, particularly in the sedentary subjects. The proximal patellar tendon can undergo substantial adaptation on tendon mechanical and morphological properties when exposed in jumping sports. Intrinsic factors such as age and body mass could influence tendon properties.

Rupture Following Biceps-to-Triceps Tendon Transfer in Adolescents and Young Adults With Spinal Cord Injury:

PubMed Central

Merenda, Lisa A.; Rutter, Laure; Curran, Kimberly; Kozin, Scott H.

2012-01-01

Background: Tendon transfer surgery can restore elbow extension in approximately 70% of persons with tetraplegia and often results in antigravity elbow extension strength. However, we have noted an almost 15% rupture/attenuation rate. Objective: This investigation was conducted to analyze potential causes in adolescents/young adults with spinal cord injury (SCI) who experienced tendon rupture or attenuation after biceps-to-triceps transfer. Methods: Medical charts of young adults with SCI who underwent biceps-to-triceps transfer and experienced tendon rupture or attenuation were reviewed. Data collected by retrospective chart review included general demographics, surgical procedure(s), use and duration of antibiotic treatment, time from tendon transfer surgery to rupture/attenuation, and method of diagnosis. Results: Twelve subjects with tetraplegia (mean age, 19 years) who underwent biceps-to-triceps reconstruction with subsequent tendon rupture or attenuation were evaluated. Mean age at time of tendon transfer was 18 years (range, 14-21 years). A fluoroquinolone was prescribed for 42% (n=5) of subjects. Tendon rupture was noted in 67% (n=8), and attenuation was noted in 33% (n=4). Average length of time from surgery to tendon rupture/attenuation was 5.7 months (range, 3-10 months). Conclusion: Potential contributing causes of tendon rupture/attenuation after transfer include surgical technique, rehabilitation, co-contraction of the transfer, poor patient compliance, and medications. In this cohort, 5 subjects were prescribed fluoroquinolones that have a US Food and Drug Administration black box concerning tendon ruptures. Currently, all candidates for upper extremity tendon transfer reconstruction are counseled on the effects of fluoroquinolones and the potential risk for tendon rupture. PMID:23459326

The Influence of External Load on Quadriceps Muscle and Tendon Dynamics during Jumping.

PubMed

Earp, Jacob E; Newton, Robert U; Cormie, Prue; Blazevich, Anthony J

2017-11-01

Tendons possess both viscous (rate-dependent) and elastic (rate-independent) properties that determine tendon function. During high-speed movements external loading increases both the magnitude (FT) and rate (RFDT) of tendon loading. The influence of external loading on muscle and tendon dynamics during maximal vertical jumping was explored. Ten resistance-trained men performed parallel-depth, countermovement vertical jumps with and without additional load (0%, 30%, 60%, and 90% of maximum squat lift strength), while joint kinetics and kinematics, quadriceps tendon length (LT) and patellar tendon FT and RFDT were estimated using integrated ultrasound, motion analysis and force platform data and muscle tendon modelling. Estimated FT and RFDT, but not peak LT, increased with external loading. Temporal comparisons between 0% and 90% loads revealed that FT was greater with 90% loading throughout the majority of the movement (11%-81% and 87%-95% movement duration). However, RFDT was greater with 90% load only during the early movement initiation phase (8%-15% movement duration) but was greater in the 0% load condition later in the eccentric phase (27%-38% movement duration). LT was longer during the early movement (12%-23% movement duration) but shorter in the late eccentric and early concentric phases (48%-55% movement duration) with 90% load. External loading positively influenced peak FT and RFDT but tendon strain appeared unaffected, suggesting no additive effect of external loading on patellar tendon lengthening during human jumping. Temporal analysis revealed that external loading resulted in a large initial RFDT that may have caused dynamic stiffening of the tendon and attenuated tendon strain throughout the movement. These results suggest that external loading influences tendon lengthening in both a load- and movement-dependent manner.

Visualization of the extra-articular portion of the long head of the biceps tendon during intra-articular shoulder arthroscopy.

PubMed

Festa, Anthony; Allert, Jesse; Issa, Kimona; Tasto, James P; Myer, Jonathan J

2014-11-01

To quantify the amount of the extra-articular long head of the biceps tendon (LHBT) seen during intra-articular shoulder arthroscopy by pulling the tendon into the joint with a probe through an anterior portal while viewing through a standard posterior portal. Intra-articular shoulder arthroscopy was performed on 10 forequarter cadaveric specimens. The extra-articular portion of the LHBT was evaluated by pulling the tendon into the joint with an arthroscopic probe inserted through an anterior portal. The tendon was marked at the pulley insertion on the humerus with a vascular clip before and after the tendon was pulled into the joint. An open deltopectoral approach was performed, and the amount of extra-articular tendon visualized was calculated as an absolute amount and in relation to nearby anatomic structures. An additional 1.9 cm (range, 1.4 to 2.6 cm) of extra-articular LHBT was viewed by pulling the tendon into the joint with an arthroscopic probe through an anterior portal during shoulder arthroscopy. This represented 30.8% of the extra-articular portion of the tendon, 47.7% of tendon in the bicipital groove, and 76.3% of the tendon that lies under the area from the pulley insertion to the distal edge of the transverse humeral ligament. During intra-articular shoulder arthroscopy, the extra-articular portion of the LHBT is incompletely visualized by pulling the tendon into the joint with a probe placed through an anterior portal while viewing through a standard posterior portal. An additional extra-articular portion of the LHBT may be viewed by pulling the tendon into the joint with an arthroscopic probe during shoulder arthroscopy. Copyright © 2014 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Decorin and biglycan are necessary for maintaining collagen fibril structure, fiber realignment, and mechanical properties of mature tendons.

PubMed

Robinson, Kelsey A; Sun, Mei; Barnum, Carrie E; Weiss, Stephanie N; Huegel, Julianne; Shetye, Snehal S; Lin, Linda; Saez, Daniel; Adams, Sheila M; Iozzo, Renato V; Soslowsky, Louis J; Birk, David E

2017-12-01

The small leucine-rich proteoglycans (SLRPs), decorin and biglycan, are key regulators of collagen fibril and matrix assembly. The goal of this work was to elucidate the roles of decorin and biglycan in tendon homeostasis. Our central hypothesis is that decorin and biglycan expression in the mature tendon would be critical for the maintenance of the structural and mechanical properties of healthy tendons. Defining the function(s) of these SLRPs in tendon homeostasis requires that effects in the mature tendon be isolated from their influence on development. Thus, we generated an inducible knockout mouse model that permits genetic ablation of decorin and biglycan expression in the mature tendon, while maintaining normal expression during development. Decorin and biglycan expression were knocked out in the mature patellar tendon with the subsequent turnover of endogenous SLRPs deposited prior to induction. The acute absence of SLRP expression was associated with changes in fibril structure with a general shift to larger diameter fibrils in the compound knockout tendons, together with fibril diameter heterogeneity. In addition, tendon mechanical properties were altered. Compared to wild-type controls, acute ablation of both genes resulted in failure of the tendon at lower loads, decreased stiffness, a trend towards decreased dynamic modulus, as well as a significant increase in percent relaxation and tissue viscosity. Collagen fiber realignment was also increased with a delayed and slower in response to load in the absence of expression. These structural and functional changes in response to an acute loss of decorin and biglycan expression in the mature tendon demonstrate a significant role for these SLRPs in adult tendon homeostasis. Copyright © 2017 Elsevier B.V. All rights reserved.

The role of three-dimensional pure bovine gelatin scaffolds in tendon healing, modeling, and remodeling: an in vivo investigation with potential clinical value.

PubMed

Oryan, Ahmad; Sharifi, Pardis; Moshiri, Ali; Silver, Ian A

2017-09-01

Large tendon defects involving extensive tissue loss present complex clinical problems. Surgical reconstruction of such injuries is normally performed by transplanting autogenous and allogenous soft tissues that are expected to remodel to mimic a normal tendon. However, the use of grafts has always been associated with significant limitations. Tissue engineering employing artificial scaffolds may provide acceptable alternatives. Gelatin is a hydrolyzed form of collagen that is bioactive, biodegradable, and biocompatible. The present study has investigated the suitability of gelatin scaffold for promoting healing of a large tendon-defect model in rabbits. An experimental model of a large tendon defect was produced by partial excision of the Achilles tendon of the left hind leg in adult rabbits. To standardize and stabilize the length of the tendon defect a modified Kessler core suture was anchored in the sectioned tendon ends. The defects were either left untreated or filled with three-dimensional gelatin scaffold. Before euthanasia 60 days after injury, the progress of healing was evaluated clinically. Samples of healing tendon were harvested at autopsy and evaluated by gross, histopathologic, scanning, and transmission electron microscopy, and by biomechanical testing. The treated animals showed superior weight-bearing and physical activity compared with those untreated, while frequency of peritendinous adhesions around the healing site was reduced. The gelatin scaffold itself was totally degraded and replaced by neo-tendon that morphologically had significantly greater numbers, diameters, density, and maturation of collagen fibrils, fibers, and fiber bundles than untreated tendon scar tissue. It also had mechanically higher ultimate load, yield load, stiffness, maximum stress and elastic modulus, when compared to the untreated tendons. Gelatin scaffold may be a valuable option in surgical reconstruction of large tendon defects.

Regeneration of Full-Thickness Rotator Cuff Tendon Tear After Ultrasound-Guided Injection With Umbilical Cord Blood-Derived Mesenchymal Stem Cells in a Rabbit Model.

PubMed

Park, Gi-Young; Kwon, Dong Rak; Lee, Sang Chul

2015-11-01

Rotator cuff tendon tear is one of the most common causes of chronic shoulder pain and disability. In this study, we investigated the therapeutic effects of ultrasound-guided human umbilical cord blood (UCB)-derived mesenchymal stem cell (MSC) injection to regenerate a full-thickness subscapularis tendon tear in a rabbit model by evaluating the gross morphology and histology of the injected tendon and motion analysis of the rabbit's activity. At 4 weeks after ultrasound-guided UCB-derived MSC injection, 7 of the 10 full-thickness subscapularis tendon tears were only partial-thickness tears, and 3 remained full-thickness tendon tears. The tendon tear size and walking capacity at 4 weeks after UCB-derived MSC injection under ultrasound guidance were significantly improved compared with the same parameters immediately after tendon tear. UCB-derived MSC injection under ultrasound guidance without surgical repair or bioscaffold resulted in the partial healing of full-thickness rotator cuff tendon tears in a rabbit model. Histology revealed that UCB-derived MSCs induced regeneration of rotator cuff tendon tear and that the regenerated tissue was predominantly composed of type I collagens. In this study, ultrasound-guided injection of human UCB-derived MSCs contributed to regeneration of the full-thickness rotator cuff tendon tear without surgical repair. The results demonstrate the effectiveness of local injection of MSCs into the rotator cuff tendon. The results of this study suggest that ultrasound-guided umbilical cord blood-derived mesenchymal stem cell injection may be a useful conservative treatment for full-thickness rotator cuff tendon tear repair. ©AlphaMed Press.

Platelet-rich plasma in tendon-related disorders: results and indications.

PubMed

Filardo, Giuseppe; Di Matteo, Berardo; Kon, Elizaveta; Merli, Giulia; Marcacci, Maurilio

2016-09-24

Platelet-rich plasma (PRP) is currently the most exploited strategy in the clinical practice to provide a regenerative stimulus for tendon healing. The aim of the present study was to systematically review the available evidence on the treatment of the main tendon disorders where PRP is currently applied. A systematic review of the literature was performed on the use of PRP as a treatment for tendinopathies focusing on the following sites: Achilles tendon, patellar tendon, rotator cuff tendons, and lateral elbow tendons. The following inclusion criteria for relevant articles were used: clinical trials written in English language up to 21 June 2016 on the use of PRP in the conservative or surgical treatment of the aforementioned tendinopathies. The research identified the following clinical trials dealing with the application of PRP in the selected tendons: 19 papers on patellar tendon (6 being RCTs: 4 dealing with PRP conservative application and 2 surgical), 24 papers on Achilles tendon (4 RCTs: 3 conservative and 1 surgical), 29 on lateral elbow tendons (17 RCTs, all conservative), and 32 on rotator cuff (22 RCTs: 18 surgical and 3 conservative). Patellar tendons seem to benefit from PRP injections, whereas in the Achilles tendon, PRP application is not indicated neither as a conservative approach nor as a surgical augmentation. Lateral elbow tendinopathy showed an improvement in most of the high-level studies, but the lack of proven superiority with respect to the more simple whole-blood injections still questions its use in the clinical practice. With regard to rotator cuff pathology, the vast majority of surgical RCTs documented a lack of beneficial effects, whereas there is still inconclusive evidence concerning its conservative application in rotator cuff disorders. Systematic review of level I-IV trials, Level IV.

Regeneration of Full-Thickness Rotator Cuff Tendon Tear After Ultrasound-Guided Injection With Umbilical Cord Blood-Derived Mesenchymal Stem Cells in a Rabbit Model

PubMed Central

Park, Gi-Young; Lee, Sang Chul

2015-01-01

Rotator cuff tendon tear is one of the most common causes of chronic shoulder pain and disability. In this study, we investigated the therapeutic effects of ultrasound-guided human umbilical cord blood (UCB)-derived mesenchymal stem cell (MSC) injection to regenerate a full-thickness subscapularis tendon tear in a rabbit model by evaluating the gross morphology and histology of the injected tendon and motion analysis of the rabbit’s activity. At 4 weeks after ultrasound-guided UCB-derived MSC injection, 7 of the 10 full-thickness subscapularis tendon tears were only partial-thickness tears, and 3 remained full-thickness tendon tears. The tendon tear size and walking capacity at 4 weeks after UCB-derived MSC injection under ultrasound guidance were significantly improved compared with the same parameters immediately after tendon tear. UCB-derived MSC injection under ultrasound guidance without surgical repair or bioscaffold resulted in the partial healing of full-thickness rotator cuff tendon tears in a rabbit model. Histology revealed that UCB-derived MSCs induced regeneration of rotator cuff tendon tear and that the regenerated tissue was predominantly composed of type I collagens. In this study, ultrasound-guided injection of human UCB-derived MSCs contributed to regeneration of the full-thickness rotator cuff tendon tear without surgical repair. The results demonstrate the effectiveness of local injection of MSCs into the rotator cuff tendon. Significance The results of this study suggest that ultrasound-guided umbilical cord blood-derived mesenchymal stem cell injection may be a useful conservative treatment for full-thickness rotator cuff tendon tear repair. PMID:26371340

HGF Mediates the Anti-inflammatory Effects of PRP on Injured Tendons

PubMed Central

Zhang, Jianying; Middleton, Kellie K.; Fu, Freddie H.; Im, Hee-Jeong; Wang, James H-C.

2013-01-01

Platelet-rich plasma (PRP) containing hepatocyte growth factor (HGF) and other growth factors are widely used in orthopaedic/sports medicine to repair injured tendons. While PRP treatment is reported to decrease pain in patients with tendon injury, the mechanism of this effect is not clear. Tendon pain is often associated with tendon inflammation, and HGF is known to protect tissues from inflammatory damages. Therefore, we hypothesized that HGF in PRP causes the anti-inflammatory effects. To test this hypothesis, we performed in vitro experiments on rabbit tendon cells and in vivo experiments on a mouse Achilles tendon injury model. We found that addition of PRP or HGF decreased gene expression of COX-1, COX-2, and mPGES-1, induced by the treatment of tendon cells in vitro with IL-1β. Further, the treatment of tendon cell cultures with HGF antibodies reduced the suppressive effects of PRP or HGF on IL-1β-induced COX-1, COX-2, and mPGES-1 gene expressions. Treatment with PRP or HGF almost completely blocked the cellular production of PGE2 and the expression of COX proteins. Finally, injection of PRP or HGF into wounded mouse Achilles tendons in vivo decreased PGE2 production in the tendinous tissues. Injection of platelet-poor plasma (PPP) however, did not reduce PGE2 levels in the wounded tendons, but the injection of HGF antibody inhibited the effects of PRP and HGF. Further, injection of PRP or HGF also decreased COX-1 and COX-2 proteins. These results indicate that PRP exerts anti-inflammatory effects on injured tendons through HGF. This study provides basic scientific evidence to support the use of PRP to treat injured tendons because PRP can reduce inflammation and thereby reduce the associated pain caused by high levels of PGE2. PMID:23840657

Biochemical, histologic, and biomechanical characterization of native and decellularized flexor tendon specimens harvested from the pelvic limbs of orthopedically normal dogs.

PubMed

Balogh, Daniel G; Biskup, Jeffery J; O'Sullivan, M Gerard; Scott, Ruth M; Groschen, Donna; Evans, Richard B; Conzemius, Michael G

2016-04-01

To evaluate the biochemical and biomechanical properties of native and decellularized superficial digital flexor tendons (SDFTs) and deep digital flexor tendons (DDFTs) harvested from the pelvic limbs of orthopedically normal dogs. 22 commercially supplied tendon specimens (10 SDFT and 12 DDFT) harvested from the pelvic limbs of 13 canine cadavers. DNA, glycosaminoglycan, collagen, and protein content were measured to biochemically compare native and decellularized SDFT and DDFT specimens. Mechanical testing was performed on 4 groups consisting of native tendons (5 SDFTs and 6 DDFTs) and decellularized tendons (5 SDFTs and 6 DDFTs). All tendons were preconditioned, and tension was applied to failure at 0.5 mm/s. Failure mode was video recorded for each tendon. Load-deformation and stress-strain curves were generated; calculations were performed to determine the Young modulus and stiffness. Biochemical and biomechanical data were statistically compared by use of the Wilcoxon rank sum test. Decellularized SDFT and DDFT specimens had significantly less DNA content than did native tendons. No significant differences were identified between native and decellularized specimens with respect to glycosaminoglycan, collagen, or protein content. Biomechanical comparison yielded no significant intra- or intergroup differences. All DDFT constructs failed at the tendon-clamp interface, whereas nearly half (4/10) of the SDFT constructs failed at midsubstance. Decellularized commercial canine SDFT and DDFT specimens had similar biomechanical properties, compared with each other and with native tendons. The decellularization process significantly decreased DNA content while minimizing loss of extracellular matrix components. Decellularized canine flexor tendons may provide suitable, biocompatible graft scaffolds for bioengineering applications such as tendon or ligament repair.

Anatomy of the Adductor Magnus Origin

PubMed Central

Obey, Mitchel R.; Broski, Stephen M.; Spinner, Robert J.; Collins, Mark S.; Krych, Aaron J.

2016-01-01

Background: The adductor magnus (AM) has historically been a potential source of confusion in patients with suspected proximal hamstring avulsion injuries. Purpose: To investigate the anatomic characteristics of the AM, including its osseous origin, anatomic dimensions, and relationship to the proximal hamstring tendons. Study Design: Descriptive laboratory study. Methods: Dissection of the AM origin was performed in 11 (8 cadavers) fresh-frozen hip-to-foot cadaveric hemipelvis specimens. The gross anatomy and architecture of the proximal hamstring and AM tendons were studied. After dissecting the hamstring tendons away from their origin, the dimension, shape, and orientation of the tendon footprints on the ischial tuberosity were determined. Results: The AM was identified in all cadaveric specimens. The mean tendon thickness (anterior to posterior [AP]) was 5.7 ± 2.9 mm. The mean tendon width (medial to lateral [ML]) was 7.1 ± 2.2 mm. The mean tendon length was 13.1 ± 8.7 cm. The mean footprint height (AP dimension) was 12.1 ± 2.9 mm, and mean footprint width (ML dimension) was 17.3 ± 7.1 mm. The mean distance between the AM footprint and the most medial aspect of the conjoint tendon footprint was 8.5 ± 4.2 mm. Tendon measurements demonstrated a considerable degree of both intra- and interspecimen variability. Conclusion: The AM tendon is consistently present just medial to the conjoint tendon at the ischial tuberosity, representing the lateral-most portion of the AM muscle. This study found wide variation in the dimensional characteristics of the AM tendon between specimens. Its shape and location can mimic the appearance of an intact hamstring (conjoint or semimembranosus) tendon intraoperatively or on diagnostic imaging, potentially misleading surgeons and radiologists. Therefore, detailed knowledge of the AM tendon anatomy, footprint anatomy, and its relationship to the hamstring muscle complex is paramount when planning surgical approach and technique. Clinical Relevance: The reported data may aid surgeons in more accurate recognition, diagnosis, and repair of proximal hamstring avulsion injuries. PMID:26798764

[A comparative study on repair of acute Achilles tendon rupture using three operating techniques].

PubMed

Wang, Ting; Mei, Guohua; Shi, Zhongmin; Chai, Yimin; Zhang, Changqing; Hou, Chunlin

2012-07-01

To compare the effectiveness of the 3 methods (traditional open Achilles tendon anastomosis, minimally invasive percutaneous Achilles tendon anastomosis, and Achilles tendon anastomosis limited incision) for acute Achilles tendon rupture so as to provide a reference for the choice of clinical treatment plans. Between December 2007 and March 2010, 69 cases of acute Achilles tendon rupture were treated by traditional open Achilles tendon anastomosis (traditional group, n=23), by minimally invasive percutaneous Achilles tendon anastomosis (minimally invasive group, n=23), and by Achilles tendon anastomosis limited incision (limited incision group, n=23). There was no significant difference in gender, age, mechanism of injury, and American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score between 3 groups (P > 0.05). Minimally invasive group and limited incision group were significantly better than traditional group in hospitalization days and blood loss (P < 0.01). Incision infection occurred in 2 cases of traditional group, and healing of incision by first intention was achieved in all patients of the other 2 groups, showing significant difference in the complication rate (P < 0.05). Re-rupture of Achilles tendon occurred in 1 case (4.3%) of minimally invasive group and limited incision group respectively; no re-rupture was found in traditional group (0), showing significant difference when compared with the other 2 groups (P < 0.05). All cases were followed up 12-18 months with an average of 14.9 months. The function of the joint was restored. The AOFAS score was more than 90 points in 3 groups at 12 months after operation, showing no significant difference among 3 groups (P > 0.05). The above 3 procedures can be used to treat acute Achilles tendon rupture. However, minimally invasive percutaneous Achilles tendon anastomosis and Achilles tendon anastomosis limited incision have the advantages of less invasion, good healing, short hospitalization days, and less postoperative complication, and have the disadvantage of increased risk for re-rupture of Achilles tendon after operations.

Accumulation of oxidized LDL in the tendon tissues of C57BL/6 or apolipoprotein E knock-out mice that consume a high fat diet: potential impact on tendon health.

PubMed

Grewal, Navdeep; Thornton, Gail M; Behzad, Hayedeh; Sharma, Aishwariya; Lu, Alex; Zhang, Peng; Reid, W Darlene; Granville Alex Scott, David J

2014-01-01

Clinical studies have suggested an association between dyslipidemia and tendon injuries or chronic tendon pain; the mechanisms underlying this association are not yet known. The objectives of this study were (1) to evaluate the impact of a high fat diet on the function of load-bearing tendons and on the distribution in tendons of oxidized low density lipoprotein (oxLDL), and (2) to examine the effect of oxLDL on tendon fibroblast proliferation and gene expression. Gene expression (Mmp2, Tgfb1, Col1a1, Col3a1), fat content (Oil Red O staining), oxLDL levels (immunohistochemistry) and tendon biomechanical properties were examined in mice (C57Bl/6 or ApoE -/-) receiving a standard or a high fat diet. Human tendon fibroblast proliferation and gene expression (COL1A1, COL3A1, MMP2) were examined following oxLDL exposure. In both types of mice (C57Bl/6 or ApoE -/-), consumption of a high fat diet led to a marked increase in oxLDL deposition in the load-bearing extracellular matrix of the tendon. The consumption of a high fat diet also reduced the failure stress and load of the patellar tendon in both mouse types, and increased Mmp2 expression. ApoE -/- mice exhibited more pronounced reductions in tendon function than wild-type mice, and decreased expression of Col1a1 compared to wild type mice. Human tendon fibroblasts responded to oxLDL by increasing their proliferation and their mRNA levels of MMP2, while decreasing their mRNA levels for COL1A1 and COL3A1. The consumption of a high fat diet resulted in deleterious changes in tendon function, and these changes may be explained in part by the effects of oxLDL, which induced a proliferative, matrix-degrading phenotype in human tenocytes.

Role of tissue-engineered artificial tendon in healing of a large Achilles tendon defect model in rabbits.

PubMed

Moshiri, Ali; Oryan, Ahmad; Meimandi-Parizi, Abdolhamid

2013-09-01

Treatment of large Achilles tendon defects is technically demanding. Tissue engineering is an option. We constructed a collagen-based artificial tendon, covered it with a polydioxanon (PDS) sheath, and studied the role of this bioimplant on experimental tendon healing in vivo. A 2-cm tendon gap was created in the left Achilles tendon of rabbits (n = 120). The animals were randomly divided into 3 groups: control (no implant), treated with tridimensional-collagen, and treated with tridimensional-collagen-bidimensional-PDS implants. Each group was divided into 2 subgroups of 60 and 120 days postinjury (DPI). Another 50 pilot animals were used to study the host-implant interaction. Physical activity of the animals was scored and ultrasonographic and bioelectrical characteristics of the injured tendons were investigated weekly. After euthanasia, macro, micro, and nano morphologies and biophysical and biomechanical characteristics of the healing tendons were studied. Treatment improved function of the animals, time dependently. At 60 and 120 DPI, the treated tendons showed significantly higher maximum load, yield, stiffness, stress, and modulus of elasticity compared with controls. The collagen implant induced inflammation and absorbed the migrating fibroblasts in the defect area. By its unique architecture, it aligned the fibroblasts and guided their proliferation and collagen deposition along the stress line of the tendon and resulted in improved collagen density, micro-amp, micro-ohm, water uptake, and delivery of the regenerated tissue. The PDS-sheath covering amplified these characteristics. The implants were gradually absorbed and replaced by a new tendon. Minimum amounts of peritendinous adhesion, muscle atrophy, and fibrosis were observed in the treated groups. Some remnants of the implants were preserved and accepted as a part of the new tendon. The implants were cytocompatible, biocompatible, biodegradable, and effective in tendon healing and regeneration. This implant may be a valuable option in clinical practice. Copyright © 2013 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

A Fibre-Reinforced Poroviscoelastic Model Accurately Describes the Biomechanical Behaviour of the Rat Achilles Tendon

PubMed Central

Heuijerjans, Ashley; Matikainen, Marko K.; Julkunen, Petro; Eliasson, Pernilla; Aspenberg, Per; Isaksson, Hanna

2015-01-01

Background Computational models of Achilles tendons can help understanding how healthy tendons are affected by repetitive loading and how the different tissue constituents contribute to the tendon’s biomechanical response. However, available models of Achilles tendon are limited in their description of the hierarchical multi-structural composition of the tissue. This study hypothesised that a poroviscoelastic fibre-reinforced model, previously successful in capturing cartilage biomechanical behaviour, can depict the biomechanical behaviour of the rat Achilles tendon found experimentally. Materials and Methods We developed a new material model of the Achilles tendon, which considers the tendon’s main constituents namely: water, proteoglycan matrix and collagen fibres. A hyperelastic formulation of the proteoglycan matrix enabled computations of large deformations of the tendon, and collagen fibres were modelled as viscoelastic. Specimen-specific finite element models were created of 9 rat Achilles tendons from an animal experiment and simulations were carried out following a repetitive tensile loading protocol. The material model parameters were calibrated against data from the rats by minimising the root mean squared error (RMS) between experimental force data and model output. Results and Conclusions All specimen models were successfully fitted to experimental data with high accuracy (RMS 0.42-1.02). Additional simulations predicted more compliant and soft tendon behaviour at reduced strain-rates compared to higher strain-rates that produce a stiff and brittle tendon response. Stress-relaxation simulations exhibited strain-dependent stress-relaxation behaviour where larger strains produced slower relaxation rates compared to smaller strain levels. Our simulations showed that the collagen fibres in the Achilles tendon are the main load-bearing component during tensile loading, where the orientation of the collagen fibres plays an important role for the tendon’s viscoelastic response. In conclusion, this model can capture the repetitive loading and unloading behaviour of intact and healthy Achilles tendons, which is a critical first step towards understanding tendon homeostasis and function as this biomechanical response changes in diseased tendons. PMID:26030436

Collagen structure of tendon relates to function.

PubMed

Franchi, Marco; Trirè, Alessandra; Quaranta, Marilisa; Orsini, Ester; Ottani, Victoria

2007-03-30

A tendon is a tough band of fibrous connective tissue that connects muscle to bone, designed to transmit forces and withstand tension during muscle contraction. Tendon may be surrounded by different structures: 1) fibrous sheaths or retinaculae; 2) reflection pulleys; 3) synovial sheaths; 4) peritendon sheaths; 5) tendon bursae. Tendons contain a) few cells, mostly represented by tenoblasts along with endothelial cells and some chondrocytes; b) proteoglycans (PGs), mainly decorin and hyaluronan, and c) collagen, mostly type I. Tendon is a good example of a high ordered extracellular matrix in which collagen molecules assemble into filamentous collagen fibrils (formed by microfibrils) which aggregate to form collagen fibers, the main structural components. It represents a multihierarchical structure as it contains collagen molecules arranged in fibrils then grouped in fibril bundles, fascicles and fiber bundles that are almost parallel to the long axis of the tendon, named as primary, secondary and tertiary bundles. Collagen fibrils in tendons show prevalently large diameter, a D-period of about 67 nm and appear built of collagen molecules lying at a slight angle (< 5 degrees). Under polarized light microscopy the collagen fiber bundles appear crimped with alternative dark and light transverse bands. In recent studies tendon crimps observed via SEM and TEM show that the single collagen fibrils suddenly changing their direction contain knots. These knots of collagen fibrils inside each tendon crimp have been termed "fibrillar crimps", and even if they show different aspects they all may fulfil the same functional role. As integral component of musculoskeletal system, the tendon acts to transmit muscle forces to the skeletal system. There is no complete understanding of the mechanisms in transmitting/absorbing tensional forces within the tendon; however it seems likely that a flattening of tendon crimps may occur at a first stage of tendon stretching. Increasing stretching, other transmission mechanisms such as an interfibrillar coupling via PGs linkages and a molecular gliding within the fibrils structure may be involved.

Treatment of peroneal nerve injuries with simultaneous tendon transfer and nerve exploration.

PubMed

Ho, Bryant; Khan, Zubair; Switaj, Paul J; Ochenjele, George; Fuchs, Daniel; Dahl, William; Cederna, Paul; Kung, Theodore A; Kadakia, Anish R

2014-08-06

Common peroneal nerve palsy leading to foot drop is difficult to manage and has historically been treated with extended bracing with expectant waiting for return of nerve function. Peroneal nerve exploration has traditionally been avoided except in cases of known traumatic or iatrogenic injury, with tendon transfers being performed in a delayed fashion after exhausting conservative treatment. We present a new strategy for management of foot drop with nerve exploration and concomitant tendon transfer. We retrospectively reviewed a series of 12 patients with peroneal nerve palsies that were treated with tendon transfer from 2005 to 2011. Of these patients, seven were treated with simultaneous peroneal nerve exploration and repair at the time of tendon transfer. Patients with both nerve repair and tendon transfer had superior functional results with active dorsiflexion in all patients, compared to dorsiflexion in 40% of patients treated with tendon transfers alone. Additionally, 57% of patients treated with nerve repair and tendon transfer were able to achieve enough function to return to running, compared to 20% in patients with tendon transfer alone. No patient had full return of native motor function resulting in excessive dorsiflexion strength. The results of our limited case series for this rare condition indicate that simultaneous nerve repair and tendon transfer showed no detrimental results and may provide improved function over tendon transfer alone.

Stretching Your Energetic Budget: How Tendon Compliance Affects the Metabolic Cost of Running

PubMed Central

Uchida, Thomas K.; Hicks, Jennifer L.; Dembia, Christopher L.; Delp, Scott L.

2016-01-01

Muscles attach to bones via tendons that stretch and recoil, affecting muscle force generation and metabolic energy consumption. In this study, we investigated the effect of tendon compliance on the metabolic cost of running using a full-body musculoskeletal model with a detailed model of muscle energetics. We performed muscle-driven simulations of running at 2–5 m/s with tendon force–strain curves that produced between 1 and 10% strain when the muscles were developing maximum isometric force. We computed the average metabolic power consumed by each muscle when running at each speed and with each tendon compliance. Average whole-body metabolic power consumption increased as running speed increased, regardless of tendon compliance, and was lowest at each speed when tendon strain reached 2–3% as muscles were developing maximum isometric force. When running at 2 m/s, the soleus muscle consumed less metabolic power at high tendon compliance because the strain of the tendon allowed the muscle fibers to operate nearly isometrically during stance. In contrast, the medial and lateral gastrocnemii consumed less metabolic power at low tendon compliance because less compliant tendons allowed the muscle fibers to operate closer to their optimal lengths during stance. The software and simulations used in this study are freely available at simtk.org and enable examination of muscle energetics with unprecedented detail. PMID:26930416

Obesity/Type II diabetes alters macrophage polarization resulting in a fibrotic tendon healing response

PubMed Central

Ackerman, Jessica E.; Geary, Michael B.; Orner, Caitlin A.; Bawany, Fatima

2017-01-01

Type II Diabetes (T2DM) dramatically impairs the tendon healing response, resulting in decreased collagen organization and mechanics relative to non-diabetic tendons. Despite this burden, there remains a paucity of information regarding the mechanisms that govern impaired healing of diabetic tendons. Mice were placed on either a high fat diet (T2DM) or low fat diet (lean) and underwent flexor tendon transection and repair surgery. Healing was assessed via mechanical testing, histology and changes in gene expression associated with collagen synthesis, matrix remodeling, and macrophage polarization. Obese/diabetic tendons healed with increased scar formation and impaired mechanical properties. Consistent with this, prolonged and excess expression of extracellular matrix (ECM) components were observed in obese/T2DM tendons. Macrophages are involved in both inflammatory and matrix deposition processes during healing. Obese/T2DM tendons healed with increased expression of markers of pro-inflammatory M1 macrophages, and elevated and prolonged expression of M2 macrophages markers that are involved in ECM deposition. Here we demonstrate that tendons from obese/diabetic mice heal with increased scar formation and increased M2 polarization, identifying excess M2 macrophage activity and matrix synthesis as a potential mechanism of the fibrotic healing phenotype observed in T2DM tendons, and as such a potential target to improve tendon healing in T2DM. PMID:28686669

Use of quantitative analysis of sonographic brightness for detection of early healing of tendon injury in horses.

PubMed

Micklethwaite, L; Wood, A K; Sehgal, C M; Polansky, M; Dowling, B A; Dart, A J; Rose, R J; Hodgson, D R

2001-08-01

To determine whether quantitative analysis of sonographic brightness could be used to detect healing of an induced injury of the superficial digital flexor tendon in horses and whether rate of healing was influenced by equine recombinant growth hormone. 8 clinically normal Standardbreds. A localized injury was created in the left and right superficial digital flexor tendons of each horse by injection of 2,000 units of collagenase. After injury, 4 horses received equine recombinant growth hormone, a possible promoter of tendon healing. Sonographic images (7.5 MHz) of the flexor tendons and ligaments of the metacarpal region were recorded on videotape prior to injury and weekly for 7 weeks after injury. Images were digitized, and sonographic brightness of tendons and ligaments was calculated. Collagenase-induced injury was sonographically similar to naturally occurring injury. After injury, sonographic brightness of the tendon decreased; after 3 weeks, brightness progressively increased, although by 7 weeks brightness had not returned to preinjury value. Equine recombinant growth hormone had no significant effect on the rate of tendon healing, as evaluated sonographically or at necropsy. As healing developed, alterations in sonographic brightness of injured tendons coincided with real changes in tendon structure. Quantitative sonographic brightness could be used to accurately monitor healing of equine tendon and ligament injuries and investigate the efficacy of various treatment regimens.

[Secondary tendon reconstruction on the thumb].

PubMed

Bickert, B; Kremer, T; Kneser, U

2016-12-01

Closed tendon ruptures of the thumb that require secondary reconstruction can affect the extensor pollicis longus (EPL), extensor pollicis brevis (EPB) and flexor pollicis longus (FPL) tendons. Treatment of rupture of the EPB tendon consists of refixation to the bone and temporary transfixation of the joint. In the case of preexisting or posttraumatic arthrosis, definitive arthrodesis of the thumb is the best procedure. Closed ruptures of the EPL and FPL tendons at the wrist joint cannot be treated by direct tendon suture. Rupture of the EPL tendon occurs after distal radius fractures either due to protruding screws or following conservative treatment especially in undisplaced fractures. Transfer of the extensor indicis tendon to the distal EPL stump is a good option and free interposition of the palmaris longus tendon is a possible alternative. The tension should be adjusted to slight overcorrection, which can be checked intraoperatively by performing the tenodesis test. Closed FPL ruptures at the wrist typically occur 3-6 months after osteosynthesis of distal radius fractures with palmar plates and are mostly characterized by crepitation and pain lasting for several weeks. They can be prevented by premature plate removal, synovectomy and carpal tunnel release. For treatment of a ruptured FPL tendon in adult patients the options for tendon reconstruction should be weighed up against the less complicated tenodesis or arthrodesis of the thumb interphalangeal joint.

Foot Health Facts for Athletes

MedlinePlus

... more likely to suffer repeated sprains, leading to chronic ankle instability. Achilles tendon disorders —Athletes are at high risk for developing disorders of the Achilles tendon. Achilles tendonitis , an inflammation of the tendon that runs down the back ...

Modified tendon stripper for obtaining palmaris longus tendon graft.

PubMed

Aköz, T; Altintaş, H; Civelek, B

1999-04-01

Tendon graft harvesting is a challenging part of hand surgery. It is not only a time-consuming procedure but also carries the potential complications associated with it. Various alternatives for this procedure are presented in the literature to overcome these difficulties. In this paper, we are presenting a series of cases in which a newly modified tendon stripper was used for tendon graft harvesting.

Implantation of a Novel Biologic and Hybridized Tissue Engineered Bioimplant in Large Tendon Defect: An In Vivo Investigation

PubMed Central

Oryan, Ahmad; Moshiri, Ali; Parizi, Abdolhamid Meimandi

2014-01-01

Surgical reconstruction of large Achilles tendon defects is technically demanding. There is no standard method, and tissue engineering may be a valuable option. We investigated the effects of 3D collagen and collagen-polydioxanone sheath (PDS) implants on a large tendon defect model in rabbits. Ninety rabbits were divided into three groups: control, collagen, and collagen-PDS. In all groups, 2 cm of the left Achilles tendon were excised and discarded. A modified Kessler suture was applied to all injured tendons to retain the gap length. The control group received no graft, the treated groups were repaired using the collagen only or the collagen-PDS prostheses. The bioelectrical characteristics of the injured areas were measured at weekly intervals. The animals were euthanized at 60 days after the procedure. Gross, histopathological and ultrastructural morphology and biophysical characteristics of the injured and intact tendons were investigated. Another 90 pilot animals were also used to investigate the inflammatory response and mechanism of graft incorporation during tendon healing. The control tendons showed severe hyperemia and peritendinous adhesion, and the gastrocnemius muscle of the control animals showed severe atrophy and fibrosis, with a loose areolar connective tissue filling the injured area. The tendons receiving either collagen or collagen-PDS implants showed lower amounts of peritendinous adhesion, hyperemia and muscle atrophy, and a dense tendon filled the defect area. Compared to the control tendons, application of collagen and collagen-PDS implants significantly improved water uptake, water delivery, direct transitional electrical current and tissue resistance to direct transitional electrical current. Compared to the control tendons, both prostheses showed significantly increased diameter, density and alignment of the collagen fibrils and maturity of the tenoblasts at ultrastructure level. Both prostheses influenced favorably tendon healing compared to the control tendons, with no significant differences between collagen and collagen-PDS groups. Implantation of the 3D collagen and collagen-PDS implants accelerated the production of a new tendon in the defect area, and may become a valuable option in clinical practice. PMID:24004331

Focal Experimental Injury Leads to Widespread Gene Expression and Histologic Changes in Equine Flexor Tendons

PubMed Central

Jacobsen, Else; Dart, Andrew J.; Mondori, Takamitsu; Horadogoda, Neil; Jeffcott, Leo B.; Little, Christopher B.; Smith, Margaret M.

2015-01-01

It is not known how extensively a localised flexor tendon injury affects the entire tendon. This study examined the extent of and relationship between histopathologic and gene expression changes in equine superficial digital flexor tendon after a surgical injury. One forelimb tendon was hemi-transected in six horses, and in three other horses, one tendon underwent a sham operation. After euthanasia at six weeks, transected and control (sham and non-operated contralateral) tendons were regionally sampled (medial and lateral halves each divided into six 3cm regions) for histologic (scoring and immunohistochemistry) and gene expression (real time PCR) analysis of extracellular matrix changes. The histopathology score was significantly higher in transected tendons compared to control tendons in all regions except for the most distal (P ≤ 0.03) with no differences between overstressed (medial) and stress-deprived (lateral) tendon halves. Proteoglycan scores were increased by transection in all but the most proximal region (P < 0.02), with increased immunostaining for aggrecan, biglycan and versican. After correcting for location within the tendon, gene expression for aggrecan, versican, biglycan, lumican, collagen types I, II and III, MMP14 and TIMP1 was increased in transected tendons compared with control tendons (P < 0.02) and decreased for ADAMTS4, MMP3 and TIMP3 (P < 0.001). Aggrecan, biglycan, fibromodulin, and collagen types I and III expression positively correlated with all histopathology scores (P < 0.001), whereas lumican, ADAMTS4 and MMP14 expression positively correlated only with collagen fiber malalignment (P < 0.001). In summary, histologic and associated gene expression changes were significant and widespread six weeks after injury to the equine SDFT, suggesting rapid and active development of tendinopathy throughout the entire length of the tendon. These extensive changes distant to the focal injury may contribute to poor functional outcomes and re-injury in clinical cases. Our data suggest that successful treatments of focal injuries will need to address pathology in the entire tendon, and that better methods to monitor the development and resolution of tendinopathy are required. PMID:25837713

Application of a novel Kalman filter based block matching method to ultrasound images for hand tendon displacement estimation.

PubMed

Lai, Ting-Yu; Chen, Hsiao-I; Shih, Cho-Chiang; Kuo, Li-Chieh; Hsu, Hsiu-Yun; Huang, Chih-Chung

2016-01-01

Information about tendon displacement is important for allowing clinicians to not only quantify preoperative tendon injuries but also to identify any adhesive scaring between tendon and adjacent tissue. The Fisher-Tippett (FT) similarity measure has recently been shown to be more accurate than the Laplacian sum of absolute differences (SAD) and Gaussian sum of squared differences (SSD) similarity measures for tracking tendon displacement in ultrasound B-mode images. However, all of these similarity measures can easily be influenced by the quality of the ultrasound image, particularly its signal-to-noise ratio. Ultrasound images of injured hands are unfortunately often of poor quality due to the presence of adhesive scars. The present study investigated a novel Kalman-filter scheme for overcoming this problem. Three state-of-the-art tracking methods (FT, SAD, and SSD) were used to track the displacements of phantom and cadaver tendons, while FT was used to track human tendons. These three tracking methods were combined individually with the proposed Kalman-filter (K1) scheme and another Kalman-filter scheme used in a previous study to optimize the displacement trajectories of the phantom and cadaver tendons. The motion of the human extensor digitorum communis tendon was measured in the present study using the FT-K1 scheme. The experimental results indicated that SSD exhibited better accuracy in the phantom experiments, whereas FT exhibited better performance for tracking real tendon motion in the cadaver experiments. All three tracking methods were influenced by the signal-to-noise ratio of the images. On the other hand, the K1 scheme was able to optimize the tracking trajectory of displacement in all experiments, even from a location with a poor image quality. The human experimental data indicated that the normal tendons were displaced more than the injured tendons, and that the motion ability of the injured tendon was restored after appropriate rehabilitation sessions. The obtained results show the potential for applying the proposed FT-K1 method in clinical applications for evaluating the tendon injury level after metacarpal fractures and assessing the recovery of an injured tendon during rehabilitation.

Intravoxel incoherent motion (IVIM) imaging in human achilles tendon.

PubMed

Wengler, Kenneth; Fukuda, Takeshi; Tank, Dharmesh; Huang, Mingqian; Gould, Elaine S; Schweitzer, Mark E; He, Xiang

2018-05-09

Limited microcirculation has been implicated in Achilles tendinopathy and may affect healing and disease progression. Existing invasive and noninvasive approaches to evaluate tendon microcirculation lack sensitivity and spatial coverage. To develop a novel Achilles tendon intravoxel incoherent motion (IVIM) MRI protocol to overcome the limitations from low tendon T 2 /T 2 * value and low intratendinous blood volume and blood velocity to evaluate tendon microcirculation. Prospective. Sixteen healthy male participants (age 31.0 ± 2.1) were recruited. A stimulated echo readout-segmented echo planar imaging (ste-RS-EPI) IVIM sequence at 3.0T. The feasibility of the proposed ste-RS-EPI IVIM protocol combined with Achilles tendon magic angle effect was evaluated. The sensitivity of the protocol was assessed by an exercise-induced intratendinous hemodynamic response in healthy participants. The vascular origin of the observed IVIM signal was validated by varying the diffusion mixing time and echo time. Two-tailed t-tests were used to evaluate differences (P < 0.05 was considered significant). Consistent with known tendon hypovascularity, the midportion Achilles tendon at baseline showed significantly lower IVIM-derived perfusion fraction (f p ) (3.1 ± 0.9%) compared to the proximal and distal Achilles tendon (6.0 ± 1.8% and 6.1 ± 2.0%, respectively; P < 0.01). Similarly, the midportion Achilles tendon exhibited significantly lower baseline blood flow index (D*×f p ) (40.9 ± 19.2, 18.3 ± 5.3, and 32.0 ± 9.4 in proximal, midportion, and distal Achilles tendon, respectively; P < 0.01). Eccentric heel-raise exercise led to ∼2 times increase of Achilles tendon blood flow in healthy participants. Consistent with its vascular origin, the estimated f p demonstrated a high dependency to IVIM protocol parameters, while the T 1 /T 2 -corrected absolute intratendinous microvascular blood volume fraction (V b ) did not vary. Achilles tendon ste-RS-EPI IVIM noninvasively assessed baseline values and exercise-induced changes to tendon microcirculation in healthy tendon. 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018. © 2018 International Society for Magnetic Resonance in Medicine.

Altered Achilles tendon function during walking in people with diabetic neuropathy: implications for metabolic energy saving.

PubMed

Petrovic, M; Maganaris, C N; Deschamps, K; Verschueren, S M; Bowling, F L; Boulton, A J M; Reeves, N D

2018-05-01

The Achilles tendon (AT) has the capacity to store and release elastic energy during walking, contributing to metabolic energy savings. In diabetes patients, it is hypothesized that a stiffer Achilles tendon may reduce the capacity for energy saving through this mechanism, thereby contributing to an increased metabolic cost of walking (CoW). The aim of this study was to investigate the effects of diabetes and diabetic peripheral neuropathy (DPN) on the Achilles tendon and plantarflexor muscle-tendon unit behavior during walking. Twenty-three nondiabetic controls (Ctrl); 20 diabetic patients without peripheral neuropathy (DM), and 13 patients with moderate/severe DPN underwent gait analysis using a motion analysis system, force plates, and ultrasound measurements of the gastrocnemius muscle, using a muscle model to determine Achilles tendon and muscle-tendon length changes. During walking, the DM and particularly the DPN group displayed significantly less Achilles tendon elongation (Ctrl: 1.81; DM: 1.66; and DPN: 1.54 cm), higher tendon stiffness (Ctrl: 210; DM: 231; and DPN: 240 N/mm), and higher tendon hysteresis (Ctrl: 18; DM: 21; and DPN: 24%) compared with controls. The muscle fascicles of the gastrocnemius underwent very small length changes in all groups during walking (~0.43 cm), with the smallest length changes in the DPN group. Achilles tendon forces were significantly lower in the diabetes groups compared with controls (Ctrl: 2666; DM: 2609; and DPN: 2150 N). The results strongly point toward the reduced energy saving capacity of the Achilles tendon during walking in diabetes patients as an important factor contributing to the increased metabolic CoW in these patients. NEW & NOTEWORTHY From measurements taken during walking we observed that the Achilles tendon in people with diabetes and particularly people with diabetic peripheral neuropathy was stiffer, was less elongated, and was subject to lower forces compared with controls without diabetes. These altered properties of the Achilles tendon in people with diabetes reduce the tendon's energy saving capacity and contribute toward the higher metabolic energy cost of walking in these patients.

Effects of sodium hyaluronate on tendon healing and adhesion formation in horses.

PubMed

Gaughan, E M; Nixon, A J; Krook, L P; Yeager, A E; Mann, K A; Mohammed, H; Bartel, D L

1991-05-01

Sodium hyaluronate reduces adhesions after tendon repair in rodents and dogs, and has been used in limited clinical trials in people. To evaluate its effect on tendon healing and adhesion formation in horses and to compare these effects with those of a compound of similar visco-elastic properties, a study was performed in horses, using a model of collagenase injection in the flexor tendons within the digital sheath. Eight clinically normal horses were randomly allotted to 2 groups. Adhesion formation between the deep digital flexor tendon and the tendon sheath at the pastern region was induced in the forelimbs of all horses. Using tenoscopic control, a 20-gauge needle was inserted into the deep digital flexor tendon of horses under general anesthesia and 0.2 ml of collagenase (2.5 mg/ml) was injected. The procedure was repeated proximally at 2 other sites, spaced 1.5 cm apart. A biopsy forceps was introduced, and a 5-mm tendon defect was created at each injection site. Group-A horses had 120 mg of sodium hyaluronate (NaHA) gel injected into the tendon sheath of one limb. Group-B horses had methylcellulose gel injected at the same sites. The contralateral limbs of horses in both groups served as surgical, but noninjected, controls. Horses were euthanatized after 8 weeks of stall rest. Ultrasonographic evaluation revealed improved tendon healing after NaHa injection, but no difference in peritendinous adhesion formation. Tendon sheath fluid volume and hyaluronic acid (HA) content were greater in NaHA-treated limbs. Gross pathologic examination revealed considerably fewer and smaller adhesions when limbs were treated with NaHA. However, significant difference in pull-out strengths was not evident between NaHA-treated and control limbs. Histologically, the deep digital flexor tendon from the NaHA-treated limbs had reduced inflammatory cell infiltration, improved tendon structure, and less intratendinous hemorrhage. Treatment with methylcullulose had no significant effect on tendon healing, adhesion size, quantity, or strength or on the volume and composition of the tendon sheath fluid. Sodium hyaluronate, administered intrathecally, appears to have a pharmaceutically beneficial action in this collagenase-induced tendinitis and adhesion model in horses.

Tendon exhibits complex poroelastic behavior at the nanoscale as revealed by high-frequency AFM-based rheology.

PubMed

Connizzo, Brianne K; Grodzinsky, Alan J

2017-03-21

Tendons transmit load from muscle to bone by utilizing their unique static and viscoelastic tensile properties. These properties are highly dependent on the composition and structure of the tissue matrix, including the collagen I hierarchy, proteoglycans, and water. While the role of matrix constituents in the tensile response has been studied, their role in compression, particularly in matrix pressurization via regulation of fluid flow, is not well understood. Injured or diseased tendons and tendon regions that naturally experience compression are known to have alterations in glycosaminoglycan content, which could modulate fluid flow and ultimately mechanical function. While recent theoretical studies have predicted tendon mechanics using poroelastic theory, no experimental data have directly demonstrated such behavior. In this study, we use high-bandwidth AFM-based rheology to determine the dynamic response of tendons to compressive loading at the nanoscale and to determine the presence of poroelastic behavior. Tendons are found to have significant characteristic dynamic relaxation behavior occurring at both low and high frequencies. Classic poroelastic behavior is observed, although we hypothesize that the full dynamic response is caused by a combination of flow-dependent poroelasticity as well as flow-independent viscoelasticity. Tendons also demonstrate regional dependence in their dynamic response, particularly near the junction of tendon and bone, suggesting that the structural and compositional heterogeneity in tendon may be responsible for regional poroelastic behavior. Overall, these experiments provide the foundation for understanding fluid-flow-dependent poroelastic mechanics of tendon, and the methodology is valuable for assessing changes in tendon matrix compressive behavior at the nanoscale. Copyright © 2017 Elsevier Ltd. All rights reserved.

Proteomic analysis reveals age-related changes in tendon matrix composition, with age- and injury-specific matrix fragmentation.

PubMed

Peffers, Mandy J; Thorpe, Chavaunne T; Collins, John A; Eong, Robin; Wei, Timothy K J; Screen, Hazel R C; Clegg, Peter D

2014-09-12

Energy storing tendons, such as the human Achilles and equine superficial digital flexor tendon (SDFT), are highly prone to injury, the incidence of which increases with aging. The cellular and molecular mechanisms that result in increased injury in aged tendons are not well established but are thought to result in altered matrix turnover. However, little attempt has been made to fully characterize the tendon proteome nor determine how the abundance of specific tendon proteins changes with aging and/or injury. The aim of this study was, therefore, to assess the protein profile of normal SDFTs from young and old horses using label-free relative quantification to identify differentially abundant proteins and peptide fragments between age groups. The protein profile of injured SDFTs from young and old horses was also assessed. The results demonstrate distinct proteomic profiles in young and old tendon, with alterations in the levels of proteins involved in matrix organization and regulation of cell tension. Furthermore, we identified several new peptide fragments (neopeptides) present in aged tendons, suggesting that there are age-specific cleavage patterns within the SDFT. Proteomic profile also differed between young and old injured tendon, with a greater number of neopeptides identified in young injured tendon. This study has increased the knowledge of molecular events associated with tendon aging and injury, suggesting that maintenance and repair of tendon tissue may be reduced in aged individuals and may help to explain why the risk of injury increases with aging. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

The Location-Specific Role of Proteoglycans in the Flexor Carpi Ulnaris Tendon

PubMed Central

Buckley, Mark R.; Huffman, George R.; Iozzo, Renato V.; Birk, David E.; Soslowsky, Louis J.

2015-01-01

Tendons like the flexor carpi ulnaris (FCU) that contain region-specific distributions of proteoglycans (PGs) as a result of the heterogeneous, multi-axial loads they are subjected to in vivo provide valuable models for understanding structure-function relationships in connective tissues. However, the contributions of specific PGs to FCU tendon mechanical properties are unknown. Therefore, the objective of this study was to determine how the location-dependent, viscoelastic mechanical properties of the FCU tendon are impacted individually by PG-associated glycosaminoglycans (GAGs) and by two small leucine-rich proteoglycans (SLRPs), biglycan and decorin. Full length FCU tendons from biglycan- and decorin-null mice were compared to wild type mice to evaluate the effects of specific SLRPs, while chondroitinase ABC digestion of isolated specimens removed from the tendon midsubstance was used to determine how chontroitin/dermatan sulfate (CS/DS) GAGs impact mechanics in mature FCU tendons. A novel combined genetic knockout/ digestion technique also was employed to compare SLRP-null and wild-type tendons in the absence of CS/DS GAGs that may impact properties in the mature state. In all genotypes, mechanical properties in the FCU tendon midsubstance were not affected by GAG digestion. Full-length tendons exhibited complex, multi-axial deformation under tension that may be associated with their in vivo loading environment. Mechanical properties were adversely affected by the absence of biglycan, and a decreased modulus localized in the center of the tendon was measured. These results help elucidate the role that local alterations in proteoglycan levels may play in processes that adversely impact tendon functionality including injury and pathology. PMID:23941206

Regional stiffening with aging in tibialis anterior tendons of mice occurs independent of changes in collagen fibril morphology

PubMed Central

Wood, Lauren K.; Arruda, Ellen M.

2011-01-01

The incidence of tendon degeneration and rupture increases with advancing age. The mechanisms underlying this increased risk remain unknown but may arise because of age-related changes in tendon mechanical properties and structure. Our purpose was to determine the effect of aging on tendon mechanical properties and collagen fibril morphology. Regional mechanical properties and collagen fibril characteristics were determined along the length of tibialis anterior (TA) tendons from adult (8- to 12-mo-old) and old (28- to 30-mo-old) mice. Tangent modulus of all regions along the tendons increased in old age, but the increase was substantially greater in the proximal region adjacent to the muscle than in the rest of the tendon. Overall end-to-end modulus increased with old age at maximum tendon strain (799 ± 157 vs. 1,419 ± 91 MPa) and at physiologically relevant strain (377 ± 137 vs. 798 ± 104 MPa). Despite the dramatic changes in tendon mechanical properties from adulthood to old age, collagen fibril morphology and packing fraction remained relatively constant in all tendon regions examined. Since tendon properties are influenced by their external loading environment, we also examined the effect of aging on TA muscle contractile properties. Maximum isometric force did not differ between the age groups. We conclude that TA tendons stiffen in a region-dependent manner throughout the life span, but the changes in mechanical properties are not accompanied by corresponding changes in collagen fibril morphology or force-generating capacity of the TA muscle. PMID:21737825

Matrix metabolism rate differs in functionally distinct tendons.

PubMed

Birch, Helen L; Worboys, Sarah; Eissa, Sabry; Jackson, Brendan; Strassburg, Sandra; Clegg, Peter D

2008-04-01

Tendon matrix integrity is vital to ensure adequate mechanical properties for efficient function. Although historically tendon was considered to be relatively inert, recent studies have shown that tendon matrix turnover is active. During normal physiological activities some tendons are subjected to stress and strains much closer to their failure properties than others. Tendons with low safety margins are those which function as energy stores such as the equine superficial digital flexor tendon (SDFT) and human Achilles tendon (AT). We postulate therefore that energy storing tendons suffer a higher degree of micro-damage and thus have a higher rate of matrix turnover than positional tendons. The hypothesis was tested using tissue from the equine SDFT and common digital extensor tendon (CDET). Matrix turnover was assessed indirectly by a combination of measurements for matrix age, markers of degradation, potential for degradation and protein expression. Results show that despite higher cellularity, the SDFT has lower relative levels of mRNA for collagen types I and III. Non-collagenous proteins, although expressed at different levels per cell, do not appear to differ between tendon types. Relative levels of mRNA for MMP1, MMP13 and both pro-MMP3 and MMP13 protein activity were significantly higher in the CDET. Correspondingly levels of cross-linked carboxyterminal telopeptide of type I collagen (ICTP) were higher in the CDET and tissue fluorescence lower suggesting more rapid turnover of the collagenous component. Reduced or inhibited collagen turnover in the SDFT may account for the high level of degeneration and subsequent injury compared to the CDET.

Flexor Tendon Repair With Looped Suture: 1 Versus 2 Knots.

PubMed

Gil, Joseph A; Skjong, Christian; Katarincic, Julia A; Got, Christopher

2016-03-01

To assess the strength of flexor tendon repair with looped suture. We hypothesized that, after passing the intact looped suture in the desired repair configuration, splitting the loop and tying 2 independent knots would increase the strength of flexor tendon repair. Thirty-two flexor tendons were harvested and were sharply transected in zone II. The tendons were repaired with a 4-strand core suture repair using 3-0 looped nonabsorbable nylon suture. The harvested tendons were randomly assigned and repaired with either a 1- or a 2-knot construct. The repaired flexor tendons were fixed in a servohydraulic material testing system and were loaded to failure either with uniaxial tension or cyclically. The average force at failure was 43 N for the 1-knot repair and 28 N for the 2-knot repair. The mode of failure of 15 of the flexor tendon repairs that were cyclically loaded to failure was suture pull-out. The average number of cycles and force in cyclic testing that caused failure of flexor tendon repairs was 134 cycles and 31 N for tendons repaired with looped 3-0 suture tied with 1 knot and 94 cycles and 33 N for tendons repaired with looped 3-0 suture tied with 2 knots. Our hypothesis was disproved by the results of this study. This study suggests that, when using looped suture, tying 2 independent knots instead of tying a single knot does not increase the strength of the flexor tendon repair. Copyright © 2016 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Ultrasound definition of tendon damage in patients with rheumatoid arthritis. Results of a OMERACT consensus-based ultrasound score focussing on the diagnostic reliability.

PubMed

Bruyn, George A W; Hanova, Petra; Iagnocco, Annamaria; d'Agostino, Maria-Antonietta; Möller, Ingrid; Terslev, Lene; Backhaus, Marina; Balint, Peter V; Filippucci, Emilio; Baudoin, Paul; van Vugt, Richard; Pineda, Carlos; Wakefield, Richard; Garrido, Jesus; Pecha, Ondrej; Naredo, Esperanza

2014-11-01

To develop the first ultrasound scoring system of tendon damage in rheumatoid arthritis (RA) and assess its intraobserver and interobserver reliability. We conducted a Delphi study on ultrasound-defined tendon damage and ultrasound scoring system of tendon damage in RA among 35 international rheumatologists with experience in musculoskeletal ultrasound. Twelve patients with RA were included and assessed twice by 12 rheumatologists-sonographers. Ultrasound examination for tendon damage in B mode of five wrist extensor compartments (extensor carpi radialis brevis and longus; extensor pollicis longus; extensor digitorum communis; extensor digiti minimi; extensor carpi ulnaris) and one ankle tendon (tibialis posterior) was performed blindly, independently and bilaterally in each patient. Intraobserver and interobserver reliability were calculated by κ coefficients. A three-grade semiquantitative scoring system was agreed for scoring tendon damage in B mode. The mean intraobserver reliability for tendon damage scoring was excellent (κ value 0.91). The mean interobserver reliability assessment showed good κ values (κ value 0.75). The most reliable were the extensor digiti minimi, the extensor carpi ulnaris, and the tibialis posterior tendons. An ultrasound reference image atlas of tenosynovitis and tendon damage was also developed. Ultrasound is a reproducible tool for evaluating tendon damage in RA. This study strongly supports a new reliable ultrasound scoring system for tendon damage. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Scaffolds in Tendon Tissue Engineering

PubMed Central

Longo, Umile Giuseppe; Lamberti, Alfredo; Petrillo, Stefano; Maffulli, Nicola; Denaro, Vincenzo

2012-01-01

Tissue engineering techniques using novel scaffold materials offer potential alternatives for managing tendon disorders. Tissue engineering strategies to improve tendon repair healing include the use of scaffolds, growth factors, cell seeding, or a combination of these approaches. Scaffolds have been the most common strategy investigated to date. Available scaffolds for tendon repair include both biological scaffolds, obtained from mammalian tissues, and synthetic scaffolds, manufactured from chemical compounds. Preliminary studies support the idea that scaffolds can provide an alternative for tendon augmentation with an enormous therapeutic potential. However, available data are lacking to allow definitive conclusion on the use of scaffolds for tendon augmentation. We review the current basic science and clinical understanding in the field of scaffolds and tissue engineering for tendon repair. PMID:22190961

Distal Attachment of Flexor Tendon Allograft: A Biomechanical Study of Different Reconstruction Techniques in Human Cadaver Hands

PubMed Central

Wei, Zhuang; Thoreson, Andrew R.; Amadio, Peter C.; An, Kai-Nan; Zhao, Chunfeng

2014-01-01

We compared the mechanical force of tendon-to-bone repair techniques for flexor tendon reconstruction. Thirty-six flexor digitorum profundus (FDP) tendons were divided into three groups based upon the repair technique: (1) suture/button repair using FDP tendon (Pullout button group), (2) suture bony anchor using FDP tendon (Suture anchor group), and (3) suture/button repair using FDP tendon with its bony attachment preserved (Bony attachment group). The repair failure force and stiffness were measured. The mean load to failure and stiffness in the bony attachment group were significantly higher than that in the pullout button and suture anchor groups. No significant difference was found in failure force and stiffness between the pullout button and suture anchor groups. An intrasynovial flexor tendon graft with its bony attachment has significantly improved tensile properties at the distal repair site when compared with a typical tendon-to-bone attachment with a button or suture anchor. The improvement in the tensile properties at the repair site may facilitate postoperative rehabilitation and reduce the risk of graft rupture. PMID:23754507

Ultrasonographic assessment of the equine palmar tendons

PubMed Central

Padaliya, N. R.; Ranpariya, J. J.; Kumar, Dharmendra; Javia, C. B.; Barvalia, D. R.

2015-01-01

Aim: The present study was conducted to evaluate the equine palmar tendon by ultrasonography (USG) in standing the position. Materials and Methods: USG of palmar tendons was performed in 40 adult horses using linear transducer having frequency of 10-18 MHz (e-soate, My Lab FIVE) and L52 linear array transducer (Titan, SonoSite) with frequencies ranging from 8 to 10 MHz. Palmar tendon was divided into 7 levels from distal to accessory carpal bone up to ergot in transverse scanning and 3 levels in longitudinal scanning. Results: The USG evaluation was very useful for diagnosis of affections of the conditions such as chronic bowed tendon, suspensory ligament desmitis, carpal sheath tenosynovitis and digital sheath effusions. The mean cross-sectional area (cm2) of affected tendons was significantly increased in affected than normal tendons. The echogenicity was also found reduced in affected tendons and ligaments along with disorganization of fiber alignment depending on the severity of lesion and injury. Conclusion: USG proved ideal diagnostic tool for diagnosis and post-treatment healing assessment of tendon injuries in horses. PMID:27047074

Validation of Greyscale-Based Quantitative Ultrasound in Manual Wheelchair Users

PubMed Central

Collinger, Jennifer L.; Fullerton, Bradley; Impink, Bradley G.; Koontz, Alicia M.; Boninger, Michael L.

2010-01-01

Objective The primary aim of this study is to establish the validity of greyscale-based quantitative ultrasound (QUS) measures of the biceps and supraspinatus tendons. Design Nine QUS measures of the biceps and supraspinatus tendons were computed from ultrasound images collected from sixty-seven manual wheelchair users. Shoulder pathology was measured using questionnaires, physical examination maneuvers, and a clinical ultrasound grading scale. Results Increased age, duration of wheelchair use, and body mass correlated with a darker, more homogenous tendon appearance. Subjects with pain during physical examination tests for biceps tenderness and acromioclavicular joint tenderness exhibited significantly different supraspinatus QUS values. Even when controlling for tendon depth, QUS measures of the biceps tendon differed significantly between subjects with healthy tendons, mild tendinosis, and severe tendinosis. Clinical grading of supraspinatus tendon health was correlated with QUS measures of the supraspinatus tendon. Conclusions Quantitative ultrasound is valid method to quantify tendinopathy and may allow for early detection of tendinosis. Manual wheelchair users are at a high risk for developing shoulder tendon pathology and may benefit from quantitative ultrasound-based research that focuses on identifying interventions designed to reduce this risk. PMID:20407304

The role of the non-collagenous matrix in tendon function.

PubMed

Thorpe, Chavaunne T; Birch, Helen L; Clegg, Peter D; Screen, Hazel R C

2013-08-01

Tendon consists of highly ordered type I collagen molecules that are grouped together to form subunits of increasing diameter. At each hierarchical level, the type I collagen is interspersed with a predominantly non-collagenous matrix (NCM) (Connect. Tissue Res., 6, 1978, 11). Whilst many studies have investigated the structure, organization and function of the collagenous matrix within tendon, relatively few have studied the non-collagenous components. However, there is a growing body of research suggesting the NCM plays an important role within tendon; adaptations to this matrix may confer the specific properties required by tendons with different functions. Furthermore, age-related alterations to non-collagenous proteins have been identified, which may affect tendon resistance to injury. This review focuses on the NCM within the tensional region of developing and mature tendon, discussing the current knowledge and identifying areas that require further study to fully understand structure-function relationships within tendon. This information will aid in the development of appropriate techniques for tendon injury prevention and treatment. © 2013 The Authors. International Journal of Experimental Pathology © 2013 International Journal of Experimental Pathology.

Hydroxyapatite-doped polycaprolactone nanofiber membrane improves tendon-bone interface healing for anterior cruciate ligament reconstruction.

PubMed

Han, Fei; Zhang, Peng; Sun, Yaying; Lin, Chao; Zhao, Peng; Chen, Jiwu

2015-01-01

Hamstring tendon autograft is a routine graft for anterior cruciate ligament (ACL) reconstruction. However, ways of improving the healing between the tendon and bone is often overlooked in clinical practice. This issue can be addressed by using a biomimetic scaffold. Herein, a biomimetic nanofiber membrane of polycaprolactone/nanohydroxyapatite/collagen (PCL/nHAp/Col) is fabricated that mimics the composition of native bone tissue for promoting tendon-bone healing. This membrane has good cytocompatibility, allowing for osteoblast cell adhesion and growth and bone formation. As a result, MC3T3 cells reveal a higher mineralization level in PCL/nHAp/Col membrane compared with PCL membrane alone. Further in vivo studies in ACL reconstruction in a rabbit model shows that PCL/nHAp/Col-wrapped tendon may afford superior tissue integration to nonwrapped tendon in the interface between the tendon and host bone as well as improved mechanical strength. This study shows that PCL/nHAp/Col nanofiber membrane wrapping of autologous tendon is effective for improving tendon healing with host bone in ACL reconstruction.

Stem Cell Applications in Tendon Disorders: A Clinical Perspective

PubMed Central

Young, Mark

2012-01-01

Tendon injuries are a common cause of morbidity and a significant health burden on society. Tendons are structural tissues connecting muscle to bone and are prone to tearing and tendinopathy, an overuse or degenerative condition that is characterized by failed healing and cellular depletion. Current treatments, for tendon tear are conservative, surgical repair or surgical scaffold reconstruction. Tendinopathy is treated by exercises, injection therapies, shock wave treatments or surgical tendon debridement. However, tendons usually heal with fibrosis and scar tissue, which has suboptimal tensile strength and is prone to reinjury, resulting in lifestyle changes with activity restriction. Preclinical studies show that cell therapies have the potential to regenerate rather than repair tendon tissue, a process termed tenogenesis. A number of different cell lines, with varying degrees of differentiation, have being evaluated including stem cells, tendon derived cells and dermal fibroblasts. Even though cellular therapies offer some potential in treating tendon disorders, there have been few published clinical trials to determine the ideal cell source, the number of cells to administer, or the optimal bioscaffold for clinical use. PMID:22448174

Surface Modification with Chemically Modified Synovial Fluid for Flexor Tendon Reconstruction in a Canine Model in Vivo

PubMed Central

Ji, Xiaoxi; Reisdorf, Ramona L.; Thoreson, Andrew R.; Berglund, Lawrence R.; Moran, Steven L.; Jay, Gregory D.; An, Kai-Nan; Amadio, Peter C.; Zhao, Chunfeng

2015-01-01

Background: Functional restoration is the major concern after flexor tendon reconstruction in the hand. The purpose of the present study was to investigate the effects of modifying the surface of extrasynovial tendon autografts with carbodiimide-derivatized synovial fluid with gelatin (cd-SF-G) on functional outcomes of flexor tendon reconstruction using a canine model. Methods: The second and fifth flexor digitorum profundus tendons from eleven dogs were transected and repaired in zone II. The dogs then had six weeks of free activity leading to tendon rupture and scar formation (the repair-failure phase). In the reconstruction phase, two autologous peroneus longus tendons from each dog were harvested; one tendon was coated with cd-SF-G and the other, with saline solution, as a control. A non-weight-bearing rehabilitation protocol was followed for six weeks after reconstruction. The digits were then harvested and evaluations of function, adhesion status, gliding resistance, attachment strength, cell viability, and histology were performed. Results: The tendons coated with cd-SF-G demonstrated significantly lower values (mean and standard deviation) compared with the saline-solution group for work of flexion (0.63 ± 0.24 versus 1.34 ± 0.42 N-mm/deg), adhesion score (3.5 ± 1.6 versus 6.1 ± 1.3), proximal adhesion breaking force (8.6 ± 3.2 versus 20.2 ± 10.2 N), and gliding resistance (0.26 ± 0.08 versus 0.46 ± 0.22 N) (p < 0.05). There was no significant difference between the cd-SF-G and saline-solution groups (p > 0.05) in distal attachment-site strength (56.9 ± 28.4 versus 77.2 ± 36.2 N), stiffness (19 ± 7.5 versus 24.5 ± 14.5 N/mm), and compressive modulus from indentation testing (4.37 ± 1.26 versus 3.98 ± 1.24 N/mm). Histological analysis showed that tendons coated with cd-SF-G had smoother surfaces and demonstrated tendon-to-bone and tendon-to-tendon incorporation. No significant difference in viable cell count between the two groups was observed on tendon culture. Conclusions: Modification of the flexor tendon surface with cd-SF-G significantly improved digital function and reduced adhesion formation without affecting graft healing and stiffness. Clinical Relevance: This study used native synovial fluid as a basic lubricating reagent to treat a tendon graft in vivo, a novel avenue for improving clinical outcomes of flexor tendon reconstruction. This methodology may also apply to other surgical procedures where postoperative adhesions impair function. PMID:26085530

Tendon Driven Finger Actuation System

NASA Technical Reports Server (NTRS)

Ihrke, Chris A. (Inventor); Reich, David M. (Inventor); Bridgwater, Lyndon (Inventor); Linn, Douglas Martin (Inventor); Askew, Scott R. (Inventor); Diftler, Myron A. (Inventor); Platt, Robert (Inventor); Hargrave, Brian (Inventor); Valvo, Michael C. (Inventor); Abdallah, Muhammad E. (Inventor);

Pentadecapeptide BPC 157 enhances the growth hormone receptor expression in tendon fibroblasts.

PubMed

Chang, Chung-Hsun; Tsai, Wen-Chung; Hsu, Ya-Hui; Pang, Jong-Hwei Su

2014-11-19

BPC 157, a pentadecapeptide derived from human gastric juice, has been demonstrated to promote the healing of different tissues, including skin, muscle, bone, ligament and tendon in many animal studies. However, the underlying mechanism has not been fully clarified. The present study aimed to explore the effect of BPC 157 on tendon fibroblasts isolated from Achilles tendon of male Sprague-Dawley rat. From the result of cDNA microarray analysis, growth hormone receptor was revealed as one of the most abundantly up-regulated genes in tendon fibroblasts by BPC 157. BPC 157 dose- and time-dependently increased the expression of growth hormone receptor in tendon fibroblasts at both the mRNA and protein levels as measured by RT/real-time PCR and Western blot, respectively. The addition of growth hormone to BPC 157-treated tendon fibroblasts dose- and time-dependently increased the cell proliferation as determined by MTT assay and PCNA expression by RT/real-time PCR. Janus kinase 2, the downstream signal pathway of growth hormone receptor, was activated time-dependently by stimulating the BPC 157-treated tendon fibroblasts with growth hormone. In conclusion, the BPC 157-induced increase of growth hormone receptor in tendon fibroblasts may potentiate the proliferation-promoting effect of growth hormone and contribute to the healing of tendon.

Pitfalls during biomechanical testing - Evaluation of different fixation methods for measuring tendons endurance properties.

PubMed

Hangody, Gy; Pánics, G; Szebényi, G; Kiss, R; Hangody, L; Pap, K

2016-03-01

The goal of the study was to find a proper technique to fix tendon grafts into an INSTRON loading machine. From 8 human cadavers, 40 grafts were collected. We removed the bone-patella tendon-bone grafts, the semitendinosus and gracilis tendons, the quadriceps tendon-bone grafts, the Achilles tendons, and the peroneus longus tendons from each lower extremity. We tested the tendon grafts with five different types of fixation devices: surgical thread (Premicron 3), general mounting clamp, wire mesh, cement fixation, and a modified clamp for an INSTRON loading machine. The mean failure load in case of surgical thread fixation was (381N ± 26N). The results with the general clamp were (527N ± 45N). The wire meshes were more promising (750N ± 21N), but did not reach the outcomes we desired. Easy slippages of the ends of the tendons from the cement encasements were observed (253N ± 18N). We then began to use Shi's clamp that could produce 977N ± 416N peak force. We combined Shi's clamp with freezing of the graft and the rupture of the tendon itself demonstrated an average force of 2198 N ± 773N. We determined that our modified frozen clamp fixed the specimens against high tensile forces.

Achilles tendon shape and echogenicity on ultrasound among active badminton players.

PubMed

Malliaras, P; Voss, C; Garau, G; Richards, P; Maffulli, N

2012-04-01

The relationship between Achilles tendon ultrasound abnormalities, including a spindle shape and heterogeneous echogenicity, is unclear. This study investigated the relationship between these abnormalities, tendon thickness, Doppler flow and pain. Sixty-one badminton players (122 tendons, 36 men, and 25 women) were recruited. Achilles tendon thickness, shape (spindle, parallel), echogenicity (heterogeneous, homogeneous) and Doppler flow (present or absent) were measured bilaterally with ultrasound. Achilles tendon pain (during or after activity over the last week) and pain and function [Victorian Institute of Sport Achilles Assessment (VISA-A)] were measured. Sixty-eight (56%) tendons were parallel with homogeneous echogenicity (normal), 22 (18%) were spindle shaped with homogeneous echogenicity, 16 (13%) were parallel with heterogeneous echogenicity and 16 (13%) were spindle shaped with heterogeneous echogenicity. Spindle shape was associated with self-reported pain (P<0.05). Heterogeneous echogenicity was associated with lower VISA-A scores than normal tendon (P<0.05). There was an ordinal relationship between normal tendon, parallel and heterogeneous and spindle shaped and heterogeneous tendons with regard to increasing thickness and likelihood of Doppler flow. Heterogeneous echogenicity with a parallel shape may be a physiological phase and may develop into heterogeneous echogenicity with a spindle shape that is more likely to be pathological. © 2010 John Wiley & Sons A/S.

Diabetes Alters Mechanical Properties and Collagen Fiber Re-Alignment in Multiple Mouse Tendons

PubMed Central

Connizzo, Brianne K.; Bhatt, Pankti R.; Liechty, Kenneth W.; Soslowsky, Louis J.

2014-01-01

Tendons function to transfer load from muscle to bone through their complex composition and hierarchical structure, consisting mainly of type I collagen. Recent evidence suggests that type II diabetes may cause alterations in collagen structure, such as irregular fibril morphology and density, which could play a role in the mechanical function of tendons. Using the db/db mouse model of type II diabetes, the diabetic skin was found to have impaired biomechanical properties when compared to the non-diabetic group. The purpose of this study was to assess the effect of diabetes on biomechanics, collagen fiber re-alignment, and biochemistry in three functionally different tendons (Achilles, supraspinatus, patellar) using the db/db mouse model. Results showed that cross-sectional area and stiffness, but not modulus, were significantly reduced in all three tendons. However, the tendon response to load (transition strain, collagen fiber re-alignment) occurred earlier in the mechanical test, contrary to expectations. In addition, the patellar tendon had an altered response to diabetes when compared to the other two tendons, with no changes in fiber realignment and decreased collagen content at the midsubstance of the tendon. Overall, type II diabetes alters tendon mechanical properties and the dynamic response to load. PMID:24833253

Effects of Trypsinization and Mineralization on Intrasynovial Tendon Allograft Healing to Bone

PubMed Central

Qu, Jin; van Alphen, Nick A.; Thoreson, Andrew R.; Chen, Qingshan; An, Kai-Nan; Amadio, Peter C.; Schmid, Thomas M.; Zhao, Chunfeng

2014-01-01

The purpose of the current study was to develop a novel technology to enhance tendon-to-bone interface healing by trypsinizing and mineralizing (TM) an intrasynovial tendon allograft in a rabbit bone tunnel model. Eight rabbit flexor digitorum profundus (FDP) tendons were used to optimize the trypsinization process. An additional 24 FDP tendons were stratified into control and TM groups; in each group, 4 tendons were used for in vitro evaluation of TM and 8 were transplanted into proximal tibial bone tunnels in rabbits. The samples were evaluated histologically and with mechanical testing at postoperative week 8. Maximum failure strength and linear stiffness were not significantly different between the control and TM tendons. A thin fibrous band of scar tissue formed at the graft-to-bone interface in the control group. However, only the TM group showed obvious new bone formation inside the tendon graft and a visible fibrocartilage layer at the bone tunnel entrance. This study is the first to explore effects of TM on the intrasynovial allograft healing to a bone tunnel. TM showed beneficial effects on chondrogenesis, osteogenesis, and integration of the intrasynovial tendon graft, but mechanical strength was the same as the control tendons in this short-term in vivo study. PMID:25611186

Tendon sheath fibroma in the thigh.

PubMed

Moretti, Vincent M; Ashana, Adedayo O; de la Cruz, Michael; Lackman, Richard D

2012-04-01

Tendon sheath fibromas are rare, benign soft tissue tumors that are predominantly found in the fingers, hands, and wrists of young adult men. This article describes a tendon sheath fibroma that developed in the thigh of a 70-year-old man, the only known tendon sheath fibroma to form in this location. Similar to tendon sheath fibromas that develop elsewhere, our patient's lesion presented as a painless, slow-growing soft tissue nodule. Physical examination revealed a firm, nontender mass with no other associated signs or symptoms. Although the imaging appearance of tendon sheath fibromas varies, our patient's lesion appeared dark on T1- and bright on T2-weighted magnetic resonance imaging. It was well marginated and enhanced with contrast.Histologically, tendon sheath fibromas are composed of dense fibrocollagenous stromas with scattered spindle-shaped fibroblasts and narrow slit-like vascular spaces. Most tendon sheath fibromas can be successfully removed by marginal excision, although 24% of lesions recur. No lesions have metastasized. Our patient's tendon sheath fibroma was removed by marginal excision, and the patient remained disease free 35 months postoperatively. Despite its rarity, tendon sheath fibroma should be included in the differential diagnosis of a thigh mass on physical examination or imaging, especially if it is painless, nontender, benign appearing, and present in men. Copyright 2012, SLACK Incorporated.

Collagen fibrils in functionally distinct tendons have differing structural responses to tendon rupture and fatigue loading.

PubMed

Herod, Tyler W; Chambers, Neil C; Veres, Samuel P

2016-09-15

In this study we investigate relationships between the nanoscale structure of collagen fibrils and the macroscale functional response of collagenous tissues. To do so, we study two functionally distinct classes of tendons, positional tendons and energy storing tendons, using a bovine forelimb model. Molecular-level assessment using differential scanning calorimetry (DSC), functional crosslink assessment using hydrothermal isometric tension (HIT) analysis, and ultrastructural assessment using scanning electron microscopy (SEM) were used to study undamaged, ruptured, and cyclically loaded samples from the two tendon types. HIT indicated differences in both crosslink type and crosslink density, with flexor tendons having more thermally stable crosslinks than the extensor tendons (higher TFmax of >90 vs. 75.1±2.7°C), and greater total crosslink density than the extensor tendons (higher t1/2 of 11.5±1.9 vs. 3.5±1.0h after NaBH4 treatment). Despite having a lower crosslink density than flexor tendons, extensor tendons were significantly stronger (37.6±8.1 vs. 23.1±7.7MPa) and tougher (14.3±3.6 vs. 6.8±3.4MJ/m(3)). SEM showed that collagen fibrils in the tougher, stronger extensor tendons were able to undergo remarkable levels of plastic deformation in the form of discrete plasticity, while those in the flexor tendons were not able to plastically deform. When cyclically loaded, collagen fibrils in extensor tendons accumulated fatigue damage rapidly in the form of kink bands, while those in flexor tendons did not accumulate significant fatigue damage. The results demonstrate that collagen fibrils in functionally distinct tendons respond differently to mechanical loading, and suggests that fibrillar collagens may be subject to a strength vs. fatigue resistance tradeoff. Collagen fibrils-nanoscale biological cables-are the fundamental load-bearing elements of all structural human tissues. While all collagen fibrils share common features, such as being composed of a precise quarter-staggered polymeric arrangement of triple-helical collagen molecules, their structure can vary significantly between tissue types, and even between different anatomical structures of the same tissue type. To understand normal function, homeostasis, and disease of collagenous tissues requires detailed knowledge of collagen fibril structure-function. Using anatomically proximate but structurally distinct tendons, we show that collagen fibrils in functionally distinct tendons have differing susceptibilities to damage under both tensile overload and cyclic fatigue loading. Our results suggest that the structure of collagen fibrils may lead to a strength versus fatigue resistance tradeoff, where high strength is gained at the expense of fatigue resistance, and vice versa. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Leukocyte-Reduced Platelet-Rich Plasma Normalizes Matrix Metabolism in Torn Human Rotator Cuff Tendons.

PubMed

Cross, Jessica A; Cole, Brian J; Spatny, Kaylan P; Sundman, Emily; Romeo, Anthony A; Nicholson, Greg P; Wagner, Bettina; Fortier, Lisa A

2015-12-01

The optimal platelet-rich plasma (PRP) for treatment of supraspinatus tendinopathy has not been determined. To evaluate the effect of low- versus high-leukocyte concentrated PRP products on catabolic and anabolic mediators of matrix metabolism in diseased rotator cuff tendons. Controlled laboratory study. Diseased supraspinatus tendons were treated with PRP made by use of 2 commercial systems: Arthrex Autologous Conditioned Plasma Double Syringe System (L(lo) PRP) and Biomet GPS III Mini Platelet Concentrate System (L(hi) PRP). Tendon explants were placed in 6-well plates and cultured in L(lo) PRP, L(hi) PRP, or control media (Dulbecco's Modified Eagle Medium + 10% fetal bovine serum) for 96 hours. Tendons were processed for hematoxylin-eosin histologic results and were scored with the modified Bonar scale. Group 1 tendons were defined as moderate tendinopathy (Bonar score <3); group 2 tendons were assessed as severely affected (Bonar score = 3). Transforming growth factor β-1 (TGFβ-1), interleukin-1β (IL-1β), interleukin-1 receptor antagonist (IL-1Ra), interleukin-6 (IL-6), interleukin-8 (IL-8), and matrix metalloproteinase-9 (MMP-9) concentrations in PRP media were measured by use of enzyme-linked immunosorbent assay after 96 hours of culture with diseased tendon. Tendon messenger RNA expression of collagen type I (COL1A1), collagen type III (COL3A1), cartilage oligomeric matrix protein (COMP), MMP-9, MMP-13, and IL-1β was measured with real-time quantitative polymerase chain reaction. Leukocytes and platelets were significantly more concentrated in L(hi) PRP compared with L(lo) PRP. Increased IL-1β was present in L(hi) PRP after culture with group 1 tendons. IL-6 was increased in L(hi) PRP after culture with group 2 tendons. Both TGFβ-1 and MMP-9 were increased in L(hi) PRP after culture with either tendon group. In L(lo) PRP cultures, IL-1Ra:IL-1β in PRP used as media and COL1A1:COL3A1 gene expression were increased for group 1 tendon cultures. Gene expression of MMP-9 and IL-1β was increased in group 2 tendons cultured in L(lo) PRP. There was no significant difference in the expression of MMP-13 or COMP in either group of tendons cultured in L(lo) PRP or L(hi) PRP. L(lo) PRP promotes normal collagen matrix synthesis and decreases cytokines associated with matrix degradation and inflammation to a greater extent than does L(hi) PRP in moderately degenerative tendons. In severely degenerative tendons, neither PRP preparation enhanced matrix synthesis. L(lo) PRP may promote healing in moderately degenerative rotator cuff tendons. © 2015 The Author(s).

Time-Dependent Alterations of MMPs, TIMPs and Tendon Structure in Human Achilles Tendons after Acute Rupture

PubMed Central

Minkwitz, Susann; Schmock, Aysha; Kurtoglu, Alper; Tsitsilonis, Serafeim; Manegold, Sebastian; Klatte-Schulz, Franka

2017-01-01

A balance between matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) is required to maintain tendon homeostasis. Variation in this balance over time might impact on the success of tendon healing. This study aimed to analyze structural changes and the expression profile of MMPs and TIMPs in human Achilles tendons at different time-points after rupture. Biopsies from 37 patients with acute Achilles tendon rupture were taken at surgery and grouped according to time after rupture: early (2–4 days), middle (5–6 days), and late (≥7 days), and intact Achilles tendons served as control. The histological score increased from the early to the late time-point after rupture, indicating the progression towards a more degenerative status. In comparison to intact tendons, qRT-PCR analysis revealed a significantly increased expression of MMP-1, -2, -13, TIMP-1, COL1A1, and COL3A1 in ruptured tendons, whereas TIMP-3 decreased. Comparing the changes over time post rupture, the expression of MMP-9, -13, and COL1A1 significantly increased, whereas MMP-3 and -10 expression decreased. TIMP expression was not significantly altered over time. MMP staining by immunohistochemistry was positive in the ruptured tendons exemplarily analyzed from early and late time-points. The study demonstrates a pivotal contribution of all investigated MMPs and TIMP-1, but a minor role of TIMP-2, -3, and -4, in the early human tendon healing process. PMID:29053586

Incidence and clinical outcomes of tendon rupture following distal radius fracture.

PubMed

White, Brian D; Nydick, Jason A; Karsky, Dawnne; Williams, Bailee D; Hess, Alfred V; Stone, Jeffrey D

2012-10-01

To evaluate the incidence of tendon rupture after nonoperative and operative management of distal radius fractures, report clinical outcomes after tendon repair or transfer, and examine volar plate and dorsal screw prominence as a predictor of tendon rupture. We performed a retrospective chart review on patients treated for tendon rupture after distal radius fracture. We evaluated active range of motion, Disabilities of Arm, Shoulder, and Hand score, grip strength, and pain score, and performed radiographic evaluation of volar plate and dorsal screw prominence in both the study group and a matched control group. There were 6 tendon ruptures in 1,359 patients (0.4%) treated nonoperatively and 8 tendon ruptures in 999 patients (0.8%) treated with volar plate fixation. At the time of final follow-up, regardless of treatment, we noted that patients had minimal pain and excellent motion and grip strength. Mean Disabilities of the Shoulder, Arm, and Hand scores were 6 for patients treated nonoperatively and 4 for those treated with volar plating. We were unable to verify volar plate or dorsal screw prominence as independent risk factors for tendon rupture after distal radius fractures. However, we recommend continued follow-up and plate removal for symptomatic patients who have volar plate prominence or dorsal screw prominence. In the event of tendon rupture, we report excellent clinical outcomes after tendon repair or tendon transfer. Therapeutic IV. Copyright © 2012 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Is the chronic painful tendinosis tendon a strong tendon?: a case study involving an Olympic weightlifter with chronic painful Jumper's knee.

PubMed

Gisslén, Karl; Ohberg, Lars; Alfredson, Håkan

2006-09-01

The chronic painful tendinosis tendon is generally considered a degenerated and weak tendon. However, this has not been scientifically verified, and is to be considered a hypothesis. We present here a case study involving a high-level Olympic weightlifter with chronic painful patellar tendinosis who started heavy-weight training very early after successful treatment with sclerosing injections. A 25-year-old super heavy-weight (+105 kg) Olympic weightlifter with 9 months duration of severe pain (prohibiting full training) in the proximal patellar tendon, where ultrasound and Doppler showed a widened tendon with structural changes and neovascularisation, was given one treatment with ultrasound and Doppler-guided injections of the sclerosing agent polidocanol. The injections targeted the neovessels posterior to the tendon. The patient was pain-free after the treatment, and already after 2-weeks he started with heavy-weight training (240 kg in deep squats) to try to qualify for the Olympics. Additional very heavy training on training camps, most often without having any discomfort or pain in the patellar tendon, resulted in Swedish records and ninth place at the European Championships 17 weeks after the treatment. Despite beating the national records, he did not qualify for the Olympics. Ultrasound and Doppler follow-ups have shown only a few remaining neovessels, and little structural tendon changes. This case questions previous theories about the weak tendinosis tendon, and stresses the importance of studies evaluating tendon strength.

Surgical Treatment for Failure of Repair of Patellar and Quadriceps Tendon Rupture With Ipsilateral Hamstring Tendon Graft.

PubMed

Maffulli, Nicola; Papalia, Rocco; Torre, Guglielmo; Denaro, Vincenzo

2017-03-01

Tears of the patellar and quadriceps tendon are common in the active population, especially in athletes. At present, several techniques for surgical repair and reconstruction are available. When reruptures occur, a reconstruction is mandatory. In the present paper, we describe a surgical technique for patellar and quadriceps tendon reconstruction using ipsilateral hamstring autograft. After routine hamstring tendon harvesting, the tendon ends are prepared using a whip stitch. A transverse tunnel is drilled in the midportion of the patella, the hamstring graft is passed through the patella, and firmly secured to the patellar tunnel openings with sutures. The details of the technique are fully described. Autologous ipsilateral hamstring tendon grafts provide a secure sound means to manage these challenging injuries.

Dental pulp stem cells express tendon markers under mechanical loading and are a potential cell source for tissue engineering of tendon-like tissue.

PubMed

Chen, Yu-Ying; He, Sheng-Teng; Yan, Fu-Hua; Zhou, Peng-Fei; Luo, Kai; Zhang, Yan-Ding; Xiao, Yin; Lin, Min-Kui

2016-12-16

Postnatal mesenchymal stem cells have the capacity to differentiate into multiple cell lineages. This study explored the possibility of dental pulp stem cells (DPSCs) for potential application in tendon tissue engineering. The expression of tendon-related markers such as scleraxis, tenascin-C, tenomodulin, eye absent homologue 2, collagens I and VI was detected in dental pulp tissue. Interestingly, under mechanical stimulation, these tendon-related markers were significantly enhanced when DPSCs were seeded in aligned polyglycolic acid (PGA) fibre scaffolds. Furthermore, mature tendon-like tissue was formed after transplantation of DPSC-PGA constructs under mechanical loading conditions in a mouse model. This study demonstrates that DPSCs could be a potential stem cell source for tissue engineering of tendon-like tissue.

Tendon Functional Extracellular Matrix

PubMed Central

Screen, H.R.C.; Birk, D.E.; Kadler, K.E.; Ramirez, F; Young, M.F.

2015-01-01

This article is one of a series, summarising views expressed at the Orthopaedic Research Society New Frontiers in Tendon Research Conference. This particular article reviews the three workshops held under the “Functional Extracellular Matrix” stream. The workshops focused on the roles of the tendon extracellular matrix, such as performing the mechanical functions of tendon, creating the local cell environment and providing cellular cues. Tendon is a complex network of matrix and cells, and its biological functions are influenced by widely-varying extrinsic and intrinsic factors such as age, nutrition, exercise levels and biomechanics. Consequently, tendon adapts dynamically during development, ageing and injury. The workshop discussions identified research directions associated with understanding cell-matrix interactions to be of prime importance for developing novel strategies to target tendon healing or repair. PMID:25640030

Synthesis, development, characterization and effectiveness of bovine pure platelet gel-collagen-polydioxanone bioactive graft on tendon healing

PubMed Central

Moshiri, Ali; Oryan, Ahmad; Meimandi-Parizi, Abdolhamid

2015-01-01

Bovine platelet gel (BPG) is an accessible and cost-effective source of growth factors which may have a value in tendon regenerative medicine. We produced a collagen implant (CI) as a tendon proper, covered it with polydioxanone (PDS) sheath to simulate paratenon and finally embedded the BPG as an active source of growth factor within the bioimplant to test whether BPG would be able to accelerate and enhance tendon regeneration and repair. After in vitro characterization of the bioactive grafts, the grafts were implanted in rabbit large tendon defect model. Untreated tendons and tendons treated with either CI or CI-PDS were served as controls for the CI-PDS-BPG. The animals were investigated clinically, ultrasonographically and haematologically for 120 days. After euthanasia, dry matter content, water uptake and delivery characteristics and also gross morphological, histopathological and scanning electron microscopic features of the healing tendons were assessed. In vitro, the activated platelets in the scaffold, released their growth factors significantly more than the controls. BPG also increased cell viability, and enhanced cellular differentiation, maturation and proliferation inside the CI-PDS compared with the controls. In vivo, the BPG modulated inflammation, increased quality and rate of fibroplasia and produced a remodelled tendon that had significantly higher collagen content and superior collagen fibril and fibre differentiation than controls. Treatment also significantly improved tendon water uptake and delivery characteristics, animals’ serum PDGF level, CI-PDS biocompatibility and biodegradability and reduced peritendinous adhesions, muscle fibrosis and atrophy. BPG was effective on tendon healing and CI-PDS-BPG may be a valuable bioscaffold in tendon reconstructive surgery. PMID:25702535

The paratenon contributes to scleraxis-expressing cells during patellar tendon healing.

PubMed

Dyment, Nathaniel A; Liu, Chia-Feng; Kazemi, Namdar; Aschbacher-Smith, Lindsey E; Kenter, Keith; Breidenbach, Andrew P; Shearn, Jason T; Wylie, Christopher; Rowe, David W; Butler, David L

2013-01-01

The origin of cells that contribute to tendon healing, specifically extrinsic epitenon/paratenon cells vs. internal tendon fibroblasts, is still debated. The purpose of this study is to determine the location and phenotype of cells that contribute to healing of a central patellar tendon defect injury in the mouse. Normal adult patellar tendon consists of scleraxis-expressing (Scx) tendon fibroblasts situated among aligned collagen fibrils. The tendon body is surrounded by paratenon, which consists of a thin layer of cells that do not express Scx and collagen fibers oriented circumferentially around the tendon. At 3 days following injury, the paratenon thickens as cells within the paratenon proliferate and begin producing tenascin-C and fibromodulin. These cells migrate toward the defect site and express scleraxis and smooth muscle actin alpha by day 7. The thickened paratenon tissue eventually bridges the tendon defect by day 14. Similarly, cells within the periphery of the adjacent tendon struts express these markers and become disorganized. Cells within the defect region show increased expression of fibrillar collagens (Col1a1 and Col3a1) but decreased expression of tenogenic transcription factors (scleraxis and mohawk homeobox) and collagen assembly genes (fibromodulin and decorin). By contrast, early growth response 1 and 2 are upregulated in these tissues along with tenascin-C. These results suggest that paratenon cells, which normally do not express Scx, respond to injury by turning on Scx and assembling matrix to bridge the defect. Future studies are needed to determine the signaling pathways that drive these cells and whether they are capable of producing a functional tendon matrix. Understanding this process may guide tissue engineering strategies in the future by stimulating these cells to improve tendon repair.

Evaluating adhesion reduction efficacy of type I/III collagen membrane and collagen-GAG resorbable matrix in primary flexor tendon repair in a chicken model.

PubMed

Turner, John B; Corazzini, Rubina L; Butler, Timothy J; Garlick, David S; Rinker, Brian D

2015-09-01

Reduction of peritendinous adhesions after injury and repair has been the subject of extensive prior investigation. The application of a circumferential barrier at the repair site may limit the quantity of peritendinous adhesions while preserving the tendon's innate ability to heal. The authors compare the effectiveness of a type I/III collagen membrane and a collagen-glycosaminoglycan (GAG) resorbable matrix in reducing tendon adhesions in an experimental chicken model of a "zone II" tendon laceration and repair. In Leghorn chickens, flexor tendons were sharply divided using a scalpel and underwent repair in a standard fashion (54 total repairs). The sites were treated with a type I/III collagen membrane, collagen-GAG resorbable matrix, or saline in a randomized fashion. After 3 weeks, qualitative and semiquantitative histological analysis was performed to evaluate the "extent of peritendinous adhesions" and "nature of tendon healing." The data was evaluated with chi-square analysis and unpaired Student's t test. For both collagen materials, there was a statistically significant improvement in the degree of both extent of peritendinous adhesions and nature of tendon healing relative to the control group. There was no significant difference seen between the two materials. There was one tendon rupture observed in each treatment group. Surgical handling characteristics were subjectively favored for type I/III collagen membrane over the collagen-GAG resorbable matrix. The ideal method of reducing clinically significant tendon adhesions after injury remains elusive. Both materials in this study demonstrate promise in reducing tendon adhesions after flexor tendon repair without impeding tendon healing in this model.

The Coracohumeral Distance in Shoulders With Traumatic and Degenerative Subscapularis Tendon Tears.

PubMed

Balke, Maurice; Banerjee, Marc; Greshake, Oliver; Hoeher, Juergen; Bouillon, Bertil; Liem, Dennis

2016-01-01

A reduced coracohumeral distance (CHD) is thought to be responsible for subcoracoid impingement. This only accounts for degenerative tendon tears. In traumatic tears, the subcoracoid space should be normal. The CHD in patients with traumatic subscapularis tendon tears is larger than that in patients with degenerative tears and does not differ from patients with an intact subscapularis tendon. Cohort study; Level of evidence, 3. A total of 83 patients with arthroscopically certified subscapularis tendon tears were included in the study. Forty-four patients had degenerative causes (group 1), and 39 had traumatic causes (group 2). The control group consisted of 20 patients with traumatic supraspinatus tendon tears and arthroscopically proven, intact subscapularis tendons (group 3). On preoperative axial magnetic resonance imaging, the distance between the CHD was measured, and the values of the 3 groups were compared using the t test. The mean (±SD) CHD in patients with degenerative subscapularis tendon tears was 8.6 ± 2.0 mm (range, 4.0-13.2 mm) and was significantly (P = .0003) smaller than that in patients with traumatic tears (10.2 ± 2.0 mm; range, 6.6-16.2 mm) or controls (10.4 ± 1.8 mm; range, 6.8-14.0 mm). The CHD of controls and patients with traumatic tears did not differ significantly (P = .7875). A CHD of less than 6 mm only occurred in patients with degenerative subscapularis tendon tears. The hypothesis that the CHD in patients with degenerative subscapularis tendon tears is significantly smaller than that in patients with traumatic tears or intact subscapularis tendons was confirmed. The CHD in patients with traumatic tears does not differ from that in controls. A CHD of less than 6 mm only occurs in patients with degenerative subscapularis tendon tears. © 2015 The Author(s).

Nonsurgical treatment and early return to activity leads to improved Achilles tendon fatigue mechanics and functional outcomes during early healing in an animal model.

PubMed

Freedman, Benjamin R; Gordon, Joshua A; Bhatt, Pankti R; Pardes, Adam M; Thomas, Stephen J; Sarver, Joseph J; Riggin, Corinne N; Tucker, Jennica J; Williams, Alexis W; Zanes, Robert C; Hast, Michael W; Farber, Daniel C; Silbernagel, Karin G; Soslowsky, Louis J

2016-12-01

Achilles tendon ruptures are common and devastating injuries; however, an optimized treatment and rehabilitation protocol has yet to be defined. Therefore, the objective of this study was to investigate the effects of surgical repair and return to activity on joint function and Achilles tendon properties after 3 weeks of healing. Sprague-Dawley rats (N = 100) received unilateral blunt transection of their Achilles tendon. Animals were then randomized into repaired or non-repaired treatments, and further randomized into groups that returned to activity after 1 week (RTA1) or after 3 weeks (RTA3) of limb casting in plantarflexion. Limb function, passive joint mechanics, and tendon properties (mechanical, organizational using high frequency ultrasound, histological, and compositional) were evaluated. Results showed that both treatment and return to activity collectively affected limb function, passive joint mechanics, and tendon properties. Functionally, RTA1 animals had increased dorsiflexion ROM and weight bearing of the injured limb compared to RTA3 animals 3-weeks post-injury. Such functional improvements in RTA1 tendons were evidenced in their mechanical fatigue properties and increased cross sectional area compared to RTA3 tendons. When RTA1 was coupled with nonsurgical treatment, superior fatigue properties were achieved compared to repaired tendons. No differences in cell shape, cellularity, GAG, collagen type I, or TGF-β staining were identified between groups, but collagen type III was elevated in RTA3 repaired tendons. The larger tissue area and increased fatigue resistance created in RTA1 tendons may prove critical for optimized outcomes in early Achilles tendon healing following complete rupture. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2172-2180, 2016. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Faster Movement Speed Results in Greater Tendon Strain during the Loaded Squat Exercise

PubMed Central

Earp, Jacob E.; Newton, Robert U.; Cormie, Prue; Blazevich, Anthony J.

2016-01-01

Introduction: Tendon dynamics influence movement performance and provide the stimulus for long-term tendon adaptation. As tendon strain increases with load magnitude and decreases with loading rate, changes in movement speed during exercise should influence tendon strain. Methods: Ten resistance-trained men [squat one repetition maximum (1RM) to body mass ratio: 1.65 ± 0.12] performed parallel-depth back squat lifts with 60% of 1RM load at three different speeds: slow fixed-tempo (TS: 2-s eccentric, 1-s pause, 2-s concentric), volitional-speed without a pause (VS) and maximum-speed jump (JS). In each condition joint kinetics, quadriceps tendon length (LT), patellar tendon force (FT), and rate of force development (RFDT) were estimated using integrated ultrasonography, motion-capture, and force platform recordings. Results: Peak LT, FT, and RFDT were greater in JS than TS (p < 0.05), however no differences were observed between VS and TS. Thus, moving at faster speeds resulted in both greater tendon stress and strain despite an increased RFDT, as would be predicted of an elastic, but not a viscous, structure. Temporal comparisons showed that LT was greater in TS than JS during the early eccentric phase (10–14% movement duration) where peak RFDT occurred, demonstrating that the tendon's viscous properties predominated during initial eccentric loading. However, during the concentric phase (61–70 and 76–83% movement duration) differing FT and similar RFDT between conditions allowed for the tendon's elastic properties to predominate such that peak tendon strain was greater in JS than TS. Conclusions: Based on our current understanding, there may be an additional mechanical stimulus for tendon adaptation when performing large range-of-motion isoinertial exercises at faster movement speeds. PMID:27630574

Nonsurgical treatment and early return to activity leads to improved Achilles tendon fatigue mechanics and functional outcomes during early healing in an animal model

PubMed Central

Freedman, BR; Gordon, JA; Bhatt, PB; Pardes, AM; Thomas, SJ; Sarver, JJ; Riggin, CN; Tucker, JJ; Williams, AW; Zanes, RC; Hast, MW; Farber, DC; Silbernagel, KG; Soslowsky, LJ

2016-01-01

Achilles tendon ruptures are common and devastating injuries; however, an optimized treatment and rehabilitation protocol has yet to be defined. Therefore, the objective of this study was to investigate the effects of surgical repair and return to activity on joint function and Achilles tendon properties after 3-weeks of healing. Sprague Dawley rats (N=100) received unilateral blunt transection of their Achilles tendon. Animals were then randomized into repaired or non-repaired treatments, and further randomized into groups that returned to activity after 1-week (RTA1) or after 3-weeks (RTA3) of limb casting in plantarflexion. Limb function, passive joint mechanics, and tendon properties (mechanical, organizational using high frequency ultrasound, histological, and compositional) were evaluated. Results showed that both treatment and return to activity collectively affected limb function, passive joint mechanics, and tendon properties. Functionally, RTA1 animals had increased dorsiflexion ROM and weight bearing of the injured limb compared to RTA3 animals 3-weeks post injury. Such functional improvements in RTA1 tendons were evidenced in their mechanical fatigue properties and increased cross sectional area compared to RTA3 tendons. When RTA1 was coupled with nonsurgical treatment, superior fatigue properties were achieved compared to repaired tendons. No differences in cell shape, cellularity, GAG, collagen type I, or TGF-β staining were identified between groups, but collagen type III was elevated in RTA3 repaired tendons. The larger tissue area and increased fatigue resistance created in RTA1 tendons may prove critical for optimized outcomes in early Achilles tendon healing following complete rupture. PMID:27038306

The influence of freezing on the tensile strength of tendon grafts : a biomechanical study.

PubMed

Arnout, Nele; Myncke, Jan; Vanlauwe, Johan; Labey, Luc; Lismont, Daniel; Bellemans, Johan

2013-08-01

We investigated the influence of freezing on the tensile strength of fresh frozen tendon grafts. The biomechanical characteristics of tendons that are less commonly used in knee surgery (tibialis anterior, tibialis posterior, peroneus longus and medial and lateral half of Achilles tendons) were compared to those of a semitendinosus and gracilis graft harvested from the same 10 multi-organ donors. All right side tendons constituted the study group and were frozen at -80 degrees C and thawed at room temperature 5 times. All left side tendons were frozen at -80 degrees C and thawed at room temperature once. There were 59 tendons in the control group and 56 in the study group. The looped grafts were clamped at one side using a custom-made freeze clamp and loaded until failure on an Instron 4505 testing machine. The average ultimate failure load was not significantly different between the control and the study group (p > 0.05). The failure load of the medial tendon Achilles was the lowest in both study and control group (p < 0.001). There was no significant difference in maximum stress, maximum displacement, maximum strain and stiffness between the control and study group (p > 0.05). From our study, we conclude that freezing tendons at -80 degrees C and thawing several times does not influence the maximum load, maximum stress, maximum displacement, maximum strain and stiffness. The medial half of the Achilles tendon is clearly the weakest tendon (p < 0.001). These findings show that tendon grafts can be frozen at -80 degrees C and thawed at room temperature several times without altering their biomechanical properties.

Minimally invasive reconstruction of chronic achilles tendon ruptures using the ipsilateral free semitendinosus tendon graft and interference screw fixation.

PubMed

Maffulli, Nicola; Loppini, Mattia; Longo, Umile Giuseppe; Maffulli, Gayle D; Denaro, Vincenzo

2013-05-01

Achilles tendon ruptures represent more than 40% of all tendon ruptures requiring surgical management. About 20% of acute Achilles tendon tears are not diagnosed at the time of injury and become chronic, necessitating more complicated management than fresh injuries. Several techniques for the reconstruction of chronic tears of the Achilles tendon have been described, but the superiority of one technique over the others has not been demonstrated. Mini-invasive reconstruction of the Achilles tendon, with a gap lesion larger than 6 cm, using the ipsilateral free semitendinosus tendon graft will result in improvement of the overall function with a low rate of complications. Case series; Level of evidence, 4. Between 2008 and 2010, the authors prospectively enrolled 28 consecutive patients (21 men and 7 women; median age, 46 years) with chronic closed ruptures of the Achilles tendon who had undergone reconstruction with a free semitendinosus tendon graft. They assessed the Achilles tendon Total Rupture Score (ATRS), maximum calf circumference, and isometric plantarflexion strength before surgery and at the last follow-up. Outcome of surgery and rate of complications were also recorded. The median follow-up after surgery was 31.4 months. The overall result of surgery was excellent/good in 26 (93%) of 28 patients. The ATRS improved from 42 (range, 29-55) to 86 (range, 78-95) (P < .0001). In the operated leg, the maximum calf circumference and isometric plantarflexion strength were significantly improved after surgery (P < .0001); however, their values remained significantly lower than those of the opposite side (P < .0001). All patients were able to walk on tiptoes and returned to their preinjury working occupation. No infections were recorded. Mini-invasive reconstruction of the Achilles tendon, with a gap lesion larger than 6 cm, using the ipsilateral free semitendinosus tendon graft provides a significant improvement of symptoms and function, although calf circumference and ankle plantarflexion strength do not recover fully.

Evidence of accumulated stress in Achilles and anterior knee tendons in elite badminton players.

PubMed

Boesen, Anders Ploug; Boesen, Morten Ilum; Koenig, Merete Juhl; Bliddal, Henning; Torp-Pedersen, Soren; Langberg, Henning

2011-01-01

Tendon-related injuries are a major problem, but the aetiology of tendinopathies is unknown. In tendinopathies as well as during unaccustomed loading, intra-tendinous flow can be detected indicating that extensive loading can provoke intra-tendinous flow. The aim of present study is to evaluate the vascular response as indicated by colour Doppler (CD) activity in both the Achilles and patella tendon after loading during high-level badminton matches. The Achilles tendon was subdivided into a mid-tendon, pre-insertional, and insertional region and the anterior knee tendons into a quadriceps-, patella- and tuberositas region. Intra-tendinous flow was measured using both a semi-quantitative grading system (CD grading) and a quantitative scoring system (CF) on colour Doppler. Intra-tendinous flow in the Achilles and anterior knee tendons was examined in fourteen single players before tournament and after 1st and 2nd match, respectively on both the dominant and non-dominant side. All players had abnormal intra-tendinous flow (Colour Doppler ≥ grade 2) in at least one tendon in at least one scan during the tournament. At baseline, only two of the 14 players had normal flow in all the tendons examined. After 1st match, tendencies to higher intra-tendinous flow were observed in both the dominant patella tendon and non-dominant quadriceps tendon (P-values n.s.). After 2nd match, intra-tendinous flow was significant increased in the dominant patella tendon (P = 0.009). In all other locations, there was a trend towards a stepwise increase in intra-tendinous flow. The preliminary results indicate that high amount of intra-tendinous flow was found in elite badminton players at baseline and was increased after repetitive loading, especially in the patella tendon (dominant leg). The colour Doppler measurement can be used to determine changes in intra-tendinous flow after repetitive loading.

A novel remaining tendon preserving repair technique leads to improved outcomes in special rotator cuff tear patterns.

PubMed

Jeon, Yoon Sang; Kim, Rag Gyu; Shin, Sang-Jin

2018-05-16

The purpose of this study was to identify the tear pattern that could be anatomically repaired by preserving the remaining tendon on footprint and evaluate clinical outcomes of patients who underwent remaining tendon preserving cuff repair. Of 523 patients with full-thickness rotator cuff tears who underwent arthroscopic repair, 41 (7.8%) patients had repairable rotator cuff tear while preserving the remaining tendon. Among them, 31 patients were followed-up for more than 2 years, including 26 patients with posterior L-shaped tear and 5 patients with transtendinous tear patterns. Clinical outcomes were evaluated using ASES and Constant score, SANE score for patient satisfaction, and VAS for pain. MRI was taken for tendon integrity 6 months postoperatively. Of the 31 patients, 11 (35.5%) had previous injury history before rotator cuff tear, including 7 (26.9%) of the 26 patients with posterior L-shaped tear and 4 (80%) of the 5 patients with transtendinous tear. The average size of preoperative cuff tear was 17.8 ± 6.8 mm in anterior-to-posterior direction and 15.2 ± 5.1 mm in medial-to-lateral direction. ASES and Constant score, SANE score, and VAS for pain were significantly (p < 0.001) improved after remaining tendon preserving rotator cuff repair. Rotator cuff tendons of 22(84.6%) patients with posterior L-shaped tear and 4(80%) patients with transtendinous tear patterns were healed. Patients who underwent rotator cuff repair with preservation of the remaining tendon on the footprint obtained satisfactory functional outcomes. Rotator cuff tears in patients who had posterior L-shaped tear extending between supraspinatus and infraspinatus tendons or transtendinous tear pattern with substantial remaining tendon could be repaired using remaining tendon preserving repair technique. Anatomic reduction of torn cuff tendon without undue tension could be achieved using the remaining tendon preserving repair technique.

An advanced glycation endproduct (AGE)-rich diet promotes accumulation of AGEs in Achilles tendon.

PubMed

Skovgaard, Dorthe; Svensson, Rene B; Scheijen, Jean; Eliasson, Pernilla; Mogensen, Pernille; Hag, Anne Mette F; Kjær, Michael; Schalkwijk, Casper G; Schjerling, Peter; Magnusson, Stig P; Couppé, Christian

2017-03-01

Advanced Glycation Endproducts (AGEs) accumulate in long-lived tissue proteins like collagen in bone and tendon causing modification of the biomechanical properties. This has been hypothesized to raise the risk of orthopedic injury such as bone fractures and tendon ruptures. We evaluated the relationship between AGE content in the diet and accumulation of AGEs in weight-bearing animal Achilles tendon. Two groups of mice (C57BL/6Ntac) were fed with either high-fat diet low in AGEs high-fat diet (HFD) ( n  = 14) or normal diet high in AGEs (ND) ( n  = 11). AGE content in ND was six to 50-fold higher than HFD The mice were sacrificed at week 40 and Achilles and tail tendons were carefully excised to compare weight and nonweight-bearing tendons. The amount of the AGEs carboxymethyllysine (CML), methylglyoxal-derived hydroimidazolone (MG-H1) and carboxyethyllysine (CEL) in Achilles and tail tendon was measured using ultraperformance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) and pentosidine with high-pressure liquid chromatography (HPLC) with fluorescent detection. AGEs in Achilles tendon were higher than in tail tendon for CML ( P  < 0.0001), CEL ( P  < 0.0001), MG-H1 and pentosidine (for both ND and HFD) ( P  < 0.0001). The AGE-rich diet (ND) resulted in an increase in CML ( P  < 0.0001), MG-H1 ( P  < 0.001) and pentosidine ( P  < 0.0001) but not CEL, in Achilles and tail tendon. This is the first study to provide evidence for AGE accumulation in injury-prone, weight-bearing Achilles tendon associated with intake of an AGE-rich diet. This indicates that food-derived AGEs may alter tendon properties and the development of tendon injuries. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Prevalence and Role of a Low-Lying Peroneus Brevis Muscle Belly in Patients With Peroneal Tendon Pathologic Features: A Potential Source of Tendon Subluxation.

PubMed

Mirmiran, Roya; Squire, Chad; Wassell, Daniel

2015-01-01

A peroneus brevis low-lying muscle belly (LLMB) is a rare anomaly. A few published studies have supported the presence of this anomaly as an etiology for a peroneal tendon tear. However, the association between a peroneus brevis LLMB and tendon subluxation has not been well explored. In the present retrospective study, the magnetic resonance imaging (MRI) and intraoperative findings of 50 consecutive patients undergoing primary peroneal tendon surgery during a 5-year period were assessed. The sensitivity and specificity of MRI compared with the intraoperative findings for identifying peroneal tendon disease were investigated. The presence of associated peroneal tendon pathologic features in patients with and without a peroneus brevis LLMB was also compared. The sensitivity of MRI was high for identifying peroneal tenosynovitis (81.58%) and tear (85.71%). Although the sensitivity of MRI for detecting a peroneus brevis LLMB (3.23%) and tendon subluxation (10.00%) was low, MRI had high specificity at 94.74% and 100%, respectively. Intraoperatively, a peroneus brevis LLMB was seen in 62.00% of the patients with chronic lateral ankle pain and was associated with 64.52% of the patients with tenosynovitis, 29.03% of those with tendon subluxation, and 80.65% of those with a peroneus brevis tendon tear. Although the presence of a peroneus brevis LLMB did not show any statistically significant association with peroneus brevis tendon subluxation, of the 10 patients with intraoperatively observed tendon subluxation, 9 had a concomitant peroneus brevis LLMB. More studies with larger patient populations are needed to better investigate the role of a peroneus brevis LLMB as a mass-occupying lesion resulting in peroneal tendon subluxation. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

How Obesity Affects Tendons?

PubMed

Abate, Michele; Salini, Vincenzo; Andia, Isabel

Several epidemiological and clinical observations have definitely demonstrated that obesity has harmful effects on tendons. The pathogenesis of tendon damage is multi-factorial. In addition to overload, attributable to the increased body weight, which significantly affects load-bearing tendons, systemic factors play a relevant role. Several bioactive peptides (chemerin, leptin, adiponectin and others) are released by adipocytes, and influence tendon structure by means of negative activities on mesenchymal cells. The ensuing systemic state of chronic, sub-clinic, low-grade inflammation can damage tendon structure. Metabolic disorders (diabetes, impaired glucose tolerance, and dislipidemia), frequently associated with visceral adiposity, are concurrent pathogenetic factors. Indeed, high glucose levels increase the formation of Advanced Glycation End-products, which in turn form stable covalent cross-links within collagen fibers, modifying their structure and functionality.Sport activities, so useful for preventing important cardiovascular complications, may be detrimental for tendons if they are submitted to intense acute or chronic overload. Therefore, two caution rules are mandatory: first, to engage in personalized soft training program, and secondly to follow regular check-up for tendon pathology.

Reconstruction of a ruptured patellar tendon using ipsilateral semitendinosus and gracilis tendons with preserved distal insertions: two case reports

PubMed Central

2013-01-01

Background Acute patellar tendon ruptures with poor tissue quality. Ruptures that have been neglected are difficult to repair. Several surgical techniques for the repair of the patellar tendon have been reported, however, these techniques remain difficult because of contractures, adhesions, and atrophy of the quadriceps muscle after surgery. Case presentation We report the cases of 2 Japanese patients (Case 1: a 16-year-old male and Case 2: a 43-year-old male) with patellar tendon ruptures who were treated by reconstruction using semitendinosus-gracilis (STG) tendons with preserved distal insertions. Retaining the original insertion of the STG appears to preserve its viability and provide the revascularization necessary to accelerate healing. Both tendons were placed in front of the patella, in a figure-of-eight fashion, providing stability to the patella. Conclusion Both patients recovered near normal strength and stability of the patellar tendon as well as restoration of function after the operation. PMID:24010848

Increased muscle belly and tendon stiffness in patients with Parkinson's disease, as measured by myotonometry.

PubMed

Marusiak, Jarosław; Jaskólska, Anna; Budrewicz, Sławomir; Koszewicz, Magdalena; Jaskólski, Artur

2011-09-01

Based on Davis's law, greater tonus of the muscle belly in individuals with Parkinson's disease can create greater tension in the tendon, leading to structural adjustment and an increase in tendon stiffness. Our study aimed to separately assess passive stiffness in the muscle belly and tendon in medicated patients with Parkinson's disease, using myotonometry. We tested 12 patients with Parkinson's disease and 12 healthy matched controls. Passive stiffness of muscle belly and tendon was estimated by myotonometry, electromyography, and mechanomyography in relaxed biceps and triceps brachii muscles. Compared with controls, patients with Parkinson's disease had higher stiffness in the muscle belly and tendon of the biceps brachii and in the tendon of the triceps brachii. In patients with Parkinson's disease, there was a positive correlation between muscle belly stiffness and parkinsonian rigidity in the biceps brachii. Patients with Parkinson's disease have higher passive stiffness of the muscle belly and tendon than healthy matched controls. Copyright © 2011 Movement Disorder Society.

Magnetic resonance imaging of the long head of the biceps tendon: benefit of coplanar image.

PubMed

Lin, Anderson; Ting, Julius; Lee, Kwo-Whei

2007-01-01

To evaluate coplanar imaging of the long head of the biceps tendon. We retrospectively compared coronal oblique magnetic resonance images aligned with the principal supraspinatus tendon and with the intra-articular biceps tendon in 21 patients. Magnetic resonance images were analyzed for lesions depicted, including superior labral anteroposterior (SLAP) tears. Arthroscopic findings were reviewed. Coronal oblique images aligned with intra-articular biceps tendon depicted 18 (86%) of 21 coplanar intra-articular biceps tendons. Coplanar images identified 6 cases of tendinosis, 1 tear, 3 intra-articular ruptures, and 20 (95.2%) of 21 exact origins of the tendon. Arthroscopy revealed 18 SLAP tears. The detection of SLAP lesions between both coronal oblique magnetic resonance images was significantly different (P = 0.007). Advantages included imaging of the intra-articular biceps tendon with least partial-volume effects, definition of SLAP lesions and the tendinous origin at the supraglenoid tubercle, depiction of intra-articular bicipital ruptures, and increased sensitivity and specificity for intra-articular lesions.

New Imaging Methods for Non-invasive Assessment of Mechanical, Structural, and Biochemical Properties of Human Achilles Tendon: A Mini Review

PubMed Central

Fouré, Alexandre

2016-01-01

The mechanical properties of tendon play a fundamental role to passively transmit forces from muscle to bone, withstand sudden stretches, and act as a mechanical buffer allowing the muscle to work more efficiently. The use of non-invasive imaging methods for the assessment of human tendon's mechanical, structural, and biochemical properties in vivo is relatively young in sports medicine, clinical practice, and basic science. Non-invasive assessment of the tendon properties may enhance the diagnosis of tendon injury and the characterization of recovery treatments. While ultrasonographic imaging is the most popular tool to assess the tendon's structural and indirectly, mechanical properties, ultrasonographic elastography, and ultra-high field magnetic resonance imaging (UHF MRI) have recently emerged as potentially powerful techniques to explore tendon tissues. This paper highlights some methodological cautions associated with conventional ultrasonography and perspectives for in vivo human Achilles tendon assessment using ultrasonographic elastography and UHF MRI. PMID:27512376

IN VIVO MEASURES OF SHEAR WAVE SPEED AS A PREDICTOR OF TENDON ELASTICITY AND STRENGTH

PubMed Central

Martin, Jack A.; Biedrzycki, Adam H.; Lee, Kenneth S.; DeWall, Ryan J.; Brounts, Sabrina H.; Murphy, William L.; Markel, Mark D.; Thelen, Darryl G.

2015-01-01

The purpose of this study was to assess the potential for ultrasound shear wave elastography (SWE) to assess tissue elasticity and ultimate stress in both intact and healing tendons. The lateral gastrocnemius (Achilles) tendons of 41 New Zealand white rabbits were surgically severed and repaired with growth factor coated sutures. SWE imaging was used to measure shear wave speed (SWS) in both the medial and lateral tendons pre-surgery, and at 2 and 4 weeks post-surgery. Rabbits were euthanized at 4 weeks, and both medial and lateral tendons underwent mechanical testing to failure. SWS significantly (p<0.001) decreased an average of 17% between the intact and post-surgical state across all tendons. SWS was significantly (p<0.001) correlated with both the tendon elastic modulus (r = 0.52) and ultimate stress (r = 0.58). Thus, ultrasound SWE is a potentially promising noninvasive technology for quantitatively assessing the mechanical integrity of pre-operative and post-operative tendons. PMID:26215492

An overview of structure, mechanical properties, and treatment for age-related tendinopathy.

PubMed

Zhou, B; Zhou, Y; Tang, K

2014-04-01

Tendons transfer tensile loads from muscle to bone, which enable joint motions and stabilize joints. Tendons sustain large mechanical loads in vivo and as a result, tendons were frequently injured. Aging has been confirmed as a predisposing factor of tendinopathy and bad recovery quality following tendon repair. Current treatment methods are generally not effective and involve either symptomatic relief with non-steroidal antiinflammatory drugs and physical therapy or surgery when conservative treatments failed. The limitation in treatment options is due to our incomplete knowledge of age-related tendinopathy. Studies over the past decades have uncovered a number of important mechanical and cellular changes of aging tendon. However, the basis of aging as a major risk factor for tendon injury and impaired tendon healing remained poorly understood. The objectives of this review are to provide an overview of the current knowledge about the aging-associated changes of structure, mechanical properties and treatment in tendon and highlight causes and therapies for age-related tendinopathy.

National Rugby League athletes and tendon tap reflex assessment: a matched cohort clinical study.

PubMed

Maurini, James; Ohmsen, Paul; Condon, Greg; Pope, Rodney; Hing, Wayne

2016-11-04

Limited research suggests elite athletes may differ from non-athletes in clinical tendon tap reflex responses. In this matched cohort study, 25 elite rugby league athletes were compared with 29 non-athletes to examine differences in tendon reflex responses. Relationships between reflex responses and lengths of players' careers were also examined. Biceps, triceps, patellar and Achilles tendon reflexes were clinically assessed. Right and left reflexes were well correlated for each tendon (r S  = 0.7-0.9). The elite rugby league athletes exhibited significantly weaker reflex responses than non-athletes in all four tendons (p < 0.005). Biceps reflexes demonstrated the largest difference and Achilles reflexes the smallest difference. Moderate negative correlations (r S  = -0.3-0.6) were observed between reflex responses and lengths of players' careers. Future research is required to further elucidate mechanisms resulting in the observed differences in tendon reflexes and to ensure clinical tendon tap examinations and findings can be interpreted appropriately in this athletic population.

Real-time sonoelastography as novel follow-up method in Achilles tendon surgery.

PubMed

Busilacchi, A; Olivieri, M; Ulisse, S; Gesuita, R; Skrami, E; Lording, T; Fusini, F; Gigante, A

2016-07-01

To evaluate the sonoelastographic features of Achilles tendon healing after percutaneous treatment using real-time sonoelastography, a new tool able to quantify deformation in biological tissues. Patients with atraumatic Achilles tendon ruptures, treated with a percutaneous technique, were assessed. Sonoelastographic evaluations were performed at the myotendinous junction, tendon body/lesion site and osteotendinous junction, both for the operated and contralateral side, at 40 days, 6 months and 1 year after surgery. Using standard regions of interest, the "strain index" (SI) was calculated as an indicator of tendon elasticity. Clinical outcomes were assessed by the ATRS questionnaire at 6 months and 1 year post-operatively and correlated with sonoelastographic findings. Sixty healthy tendons from 30 volunteers were used to provide a healthy control range. Twenty-five patients were recruited for this study. The SI in treated tendons showed progressive stiffening over time, especially at myotendinous junction and at the site of the sutured lesion, resulting in significantly higher stiffness than both the contralateral tendon and healthy volunteers. Peak thickness of treated tendons occurred at 6 months, with a tendency to reduce at 1 year, while never achieving a normal physiological state. Greatest remodelling was seen at the lesion site. The contralateral tendon showed significant thickening at the myotendinous and osteotendinous junctions. The SI of the contralateral tendon was found to be stiffer than physiological values found in the control group. ATRS score improved significantly between 6 months and 1 year, being negatively correlated with the SI (p < 0.001). RTSE showed that operatively treated Achilles tendons become progressively stiffer during follow-up, while the ATRS score improved. From a biomechanical point of view, at 1 year after surgery Achilles tendons did not show a "restitutio ad integrum". Real-time sonoelastography provides more qualitative and quantitative details in the diagnostics and follow-up of Achilles tendon conditions as the post-operative evolution of the repairing tissue. Diagnostic and therapeutic study, Level III.

Accumulation of Oxidized LDL in the Tendon Tissues of C57BL/6 or Apolipoprotein E Knock-Out Mice That Consume a High Fat Diet: Potential Impact on Tendon Health

PubMed Central

Grewal, Navdeep; Thornton, Gail M.; Behzad, Hayedeh; Sharma, Aishwariya; Lu, Alex; Zhang, Peng; Reid, W. Darlene; Granville, David J.; Scott, Alex

2014-01-01

Objective Clinical studies have suggested an association between dyslipidemia and tendon injuries or chronic tendon pain; the mechanisms underlying this association are not yet known. The objectives of this study were (1) to evaluate the impact of a high fat diet on the function of load-bearing tendons and on the distribution in tendons of oxidized low density lipoprotein (oxLDL), and (2) to examine the effect of oxLDL on tendon fibroblast proliferation and gene expression. Methods Gene expression (Mmp2, Tgfb1, Col1a1, Col3a1), fat content (Oil Red O staining), oxLDL levels (immunohistochemistry) and tendon biomechanical properties were examined in mice (C57Bl/6 or ApoE -/-) receiving a standard or a high fat diet. Human tendon fibroblast proliferation and gene expression (COL1A1, COL3A1, MMP2) were examined following oxLDL exposure. Results In both types of mice (C57Bl/6 or ApoE -/-), consumption of a high fat diet led to a marked increase in oxLDL deposition in the load-bearing extracellular matrix of the tendon. The consumption of a high fat diet also reduced the failure stress and load of the patellar tendon in both mouse types, and increased Mmp2 expression. ApoE -/- mice exhibited more pronounced reductions in tendon function than wild-type mice, and decreased expression of Col1a1 compared to wild type mice. Human tendon fibroblasts responded to oxLDL by increasing their proliferation and their mRNA levels of MMP2, while decreasing their mRNA levels for COL1A1 and COL3A1. Conclusion The consumption of a high fat diet resulted in deleterious changes in tendon function, and these changes may be explained in part by the effects of oxLDL, which induced a proliferative, matrix-degrading phenotype in human tenocytes. PMID:25502628

Asymptomatic Achilles tendon pathology is associated with a central fat distribution in men and a peripheral fat distribution in women: a cross sectional study of 298 individuals

PubMed Central

2010-01-01

Background Adiposity is a modifiable factor that has been implicated in tendinopathy. As tendon pain reduces physical activity levels and can lead to weight gain, associations between tendon pathology and adiposity must be studied in individuals without tendon pain. Therefore, the purpose of this study was to determine whether fat distribution was associated with asymptomatic Achilles tendon pathology. Methods The Achilles tendons of 298 individuals were categorised as normal or pathological using diagnostic ultrasound. Fat distribution was determined using anthropometry (waist circumference, waist hip ratio [WHR]) and dual-energy x-ray absorptiometry. Results Asymptomatic Achilles tendon pathology was more evident in men (13%) than women (5%) (p = 0.007). Men with tendon pathology were older (50.9 ± 10.4, 36.3 ± 11.3, p < 0.001), had greater WHR (0.926 ± 0.091, 0.875 ± 0.065, p = 0.039), higher android/gynoid fat mass ratio (0.616 ± 0.186, 0.519 ± 0.142, p = 0.014) and higher upper-body/lower body fat mass ratio (2.346 ± 0.630, 2.022 ± 0.467, p = 0.013). Men older than 40 years with a waist circumference >83 cm had the greatest prevalence of tendon pathology (33%). Women with tendon pathology were older (47.4 ± 10.0, 36.0 ± 10.3, p = 0.008), had less total fat (17196 ± 3173 g, 21626 ± 7882 g, p = 0.009), trunk fat (7367 ± 1662 g, 10087 ± 4152 g, p = 0.003) and android fat (1117 ± 324 g, 1616 ± 811 g, p = 0.005). They had lower central/peripheral fat mass ratios (0.711 ± 0.321 g, 0.922 ± 0.194 g, p = 0.004) than women with normal tendons. Women with tendon pathology were more often menopausal (63%, 13%, p = 0.002). Conclusions Men with Achilles tendon pathology were older and had a central fat distribution. Women with tendon pathology were older and had a peripheral fat distribution. An interaction between age and waist circumference was observed among men. PMID:20196870

Direct Lentiviral-Cyclooxygenase 2 Application to the Tendon-Bone Interface Promotes Osteointegration and Enhances Return of the Pull-Out Tensile Strength of the Tendon Graft in a Rat Model of Biceps Tenodesis

PubMed Central

Wergedal, Jon E.; Stiffel, Virginia; Lau, Kin-Hing William

2014-01-01

This study sought to determine if direct application of the lentiviral (LV)-cyclooxygenase 2 (COX2) vector to the tendon-bone interface would promote osteointegration of the tendon graft in a rat model of biceps tenodesis. The LV-COX2 gene transfer strategy was chosen for investigation because a similar COX2 gene transfer strategy promoted bony bridging of the fracture gap during bone repair, which involves similar histologic transitions that occur in osteointegration. Briefly, a 1.14-mm diameter tunnel was drilled in the mid-groove of the humerus of adult Fischer 344 rats. The LV-COX2 or βgal control vector was applied directly into the bone tunnel and onto the end of the tendon graft, which was then pulled into the bone tunnel. A poly-L-lactide pin was press-fitted into the tunnel as interference fixation. Animals were sacrificed at 3, 5, or 8 weeks for histology analysis of osteointegration. The LV-COX2 gene transfer strategy enhanced neo-chondrogenesis at the tendon-bone interface but with only marginal effect on de novo bone formation. The tendon-bone interface of the LV-COX2-treated tenodesis showed the well-defined tendon-to-fibrocartilage-to-bone histologic transitions that are indicative of osteointegration of the tendon graft. The LV-COX2 in vivo gene transfer strategy also significantly enhanced angiogenesis at the tendon-bone interface. To determine if the increased osteointegration was translated into an improved pull-out mechanical strength property, the pull-out tensile strength of the LV-COX2-treated tendon grafts was determined with a pull-out mechanical testing assay. The LV-COX2 strategy yielded a significant improvement in the return of the pull-out strength of the tendon graft after 8 weeks. In conclusion, the COX2-based in vivo gene transfer strategy enhanced angiogenesis, osteointegration and improved return of the pull-out strength of the tendon graft. Thus, this strategy has great potential to be developed into an effective therapy to promote tendon-to-bone healing after tenodesis or related surgeries. PMID:24848992

Inducement of semitendinosus tendon regeneration to the pes anserinus after its harvest for anterior cruciate ligament reconstruction-A new inducer grafting technique

PubMed Central

2012-01-01

Purpose To investigate the usefulness of the “inducer grafting” technique for regeneration of the semitendinosus (ST) tendon after its harvest for anterior cruciate ligament (ACL) reconstruction. Methods Twenty knees of 20 patients (mean age at the time of surgery, 23.1 years) underwent ACL reconstruction with a double bundle autograft using the ST tendon (7 patients) and the ST + the gracilis (G) tendons (13 patients). “Inducer grafting” technique After harvesting the ST tendon, a passing pin with a loop thread is inserted along with the tendon stripper. The passing pin is pulled out from the medial thigh and the loop thread retained. As an inducer graft, the ST tendon branch is used. After the ACL graft has been secured, the inducer graft is sutured to the pes anserinus and the proximal end passed through by pulling the thread out. Then the inducer graft is placed within the tendon canal. The mean follow-up period was 15 months. The presence and morphology of the regenerated ST tendon were examined by MRI. And the isometric hamstring strength was examined at 45°, 90° and 120° of knee flexion. Results One month after the operation in all the patients, MRI demonstrated a low-intensity structure at the anatomical location of the ST, at the level of the superior pole of the patella and the joint line, apparently representing the regenerated ST tendon. Four months after the operation, the distal portion of the regenerated ST tendon had reached the pes anserinus in all patients. Twelve months after the operation, the regenerated ST tendon was hypertrophic in 19 of the 20 patients (95%). The isometric knee flexion torque of the ACL-reconstructed limb was significantly lower at 90° and 120° compared with the contralateral limb. Conclusion These results suggest that the “inducer grafting” technique is able to improve the regeneration rate of the harvested ST tendon and promote hypertrophy of the regenerated ST tendon, extending all the way to the pes anserinus. However, this technique couldn’t improve the deficits in knee flexion torque after ACL reconstruction. PMID:22607724

IFSSH Flexor Tendon Committee report 2014: from the IFSSH Flexor Tendon Committee (Chairman: Jin Bo Tang).

PubMed

Tang, Jin Bo; Chang, James; Elliot, David; Lalonde, Donald H; Sandow, Michael; Vögelin, Esther

2014-01-01

Hand surgeons continue to search for the best surgical flexor tendon repair and treatment of the tendon sheaths and pulleys, and they are attempting to establish postoperative regimens that fit diverse clinical needs. It is the purpose of this report to present the current views, methods, and suggestions of six senior hand surgeons from six different countries - all experienced in tendon repair and reconstruction. Although certainly there is common ground, the report presents provocative views and approaches. The report reflects an update in the views of the committee. We hope that it is helpful to surgeons and therapists in treating flexor tendon injuries.

Tension Regulation at the Suture Lines for Repair of Neglected Achilles Tendon Laceration.

PubMed

Massoud, Elsayed Ibraheem Elsayed

2017-03-01

Operative intervention is the preferred option for management of the neglected laceration of the Achilles tendon. However, the commonly used techniques rarely follow the principles of the regenerative medicine for the restoration of the lost tissue. This study postulated that incorporation of the autogenous tendon graft would properly progress when the interplay between mechanical loading and healing phases was correctly applied. A prospective study included 15 patients who were treated for neglected Achilles tendon laceration using the technique of lengthening of the proximal tendon stump. An absorbable reinforcement suture was used for control of the mechanical environment at the suture lines. By an average 5 years of the prospective follow-up, all the repaired tendons had restored continuity and length. The calf circumference equalized to the uninjured side in 12 patients. However, 3 patients had calf atrophy but they improved compared to the preoperative measurements. Sonogram confirmed the restoration of the normal thickness and the gliding characteristics of the repaired tendon. The technique restored continuity and tension of the repaired tendon, preserved the calf circumference, and prevented peritendinous adhesions. The absorbable reinforcement suture spontaneously allowed for the mechanical loading of the grafted tendon. Level IV, case series.

A rare knee extensor mechanism injury: Vastus intermedius tendon rupture.

PubMed

Cetinkaya, Engin; Aydin, Canan Gonen; Akman, Yunus Emre; Gul, Murat; Arikan, Yavuz; Aycan, Osman Emre; Kabukcuoglu, Yavuz Selim

2015-01-01

Quadriceps tendon injuries are rare. There is a limited number of studies in the literature, reporting partial quadriceps tendon ruptures. We did not find any study reporting an isolated vastus intermedius tendon injury in the literature. A 22 years old professional rugby player with the complaints of pain in the right lower limb, decreased range of motion in right knee and a mass in the mid-anterior of the right thigh applied following an overloading on his hyperflexed knee during a rugby match. T2 sequence magnetic resonance images revealed discontinuity in the vastus intermedius tendon and intramuscular hematoma. The patient has been conservatively treated. Quadriceps tendon ruptures generally occur after the 4th decade in the presence of degenerative changes. Our case is a young professional rugby player. Isolated vastus intermedius tendon rupture is unusual. Conservative treatment is performed as the intermedius tendon is in the deepest layer of the quadriceps muscle. We report the first case of isolated rupture of the vastus intermedius tendon in the literature and we claim that disorder may be succesfully treated with conservative treatment and adequate physiotheraphy. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

A rare knee extensor mechanism injury: Vastus intermedius tendon rupture

PubMed Central

Cetinkaya, Engin; Aydin, Canan Gonen; Akman, Yunus Emre; Gul, Murat; Arikan, Yavuz; Aycan, Osman Emre; Kabukcuoglu, Yavuz Selim

2015-01-01

Introduction Quadriceps tendon injuries are rare. There is a limited number of studies in the literature, reporting partial quadriceps tendon ruptures. We did not find any study reporting an isolated vastus intermedius tendon injury in the literature. Presentation of case A 22 years old professional rugby player with the complaints of pain in the right lower limb, decreased range of motion in right knee and a mass in the mid-anterior of the right thigh applied following an overloading on his hyperflexed knee during a rugby match. T2 sequence magnetic resonance images revealed discontinuity in the vastus intermedius tendon and intramuscular hematoma. The patient has been conservatively treated. Discussion Quadriceps tendon ruptures generally occur after the 4th decade in the presence of degenerative changes. Our case is a young professional rugby player. Isolated vastus intermedius tendon rupture is unusual. Conservative treatment is performed as the intermedius tendon is in the deepest layer of the quadriceps muscle. Conclusion We report the first case of isolated rupture of the vastus intermedius tendon in the literature and we claim that disorder may be succesfully treated with conservative treatment and adequate physiotheraphy. PMID:26298093

Measuring Regional Changes in Damaged Tendon

NASA Astrophysics Data System (ADS)

Frisch, Catherine Kayt Vincent

Mechanical properties of tendon predict tendon health and function, but measuring these properties in vivo is difficult. An ultrasound-based (US) analysis technique called acoustoelastography (AE) uses load-dependent changes in the reflected US signal to estimate tissue stiffness non-invasively. This thesis explores whether AE can provide information about stiffness alteration resulting from tendon tears both ex vivo and in vivo. An ex vivo ovine infraspinatus tendon model suggests that the relative load transmitted by the different tendon layers transmit different fractions of the load and that ultrasound echo intensity change during cyclic loading decreases, becoming less consistent once the tendon is torn. An in vivo human tibialis anterior tendon model using electrically stimulated twitch contractions investigated the feasibility of measuring the effect in vivo. Four of the five subjects showed the expected change and that the muscle contraction times calculated using the average grayscale echo intensity change compared favorably with the times calculated based on the force data. Finally an AE pilot study with patients who had rotator cuff tendon tears found that controlling the applied load and the US view of the system will be crucial to a successful in vivo study.

Freezing does not alter multiscale tendon mechanics and damage mechanisms in tension.

PubMed

Lee, Andrea H; Elliott, Dawn M

2017-12-01

It is common in biomechanics to use previously frozen tissues, where it is assumed that the freeze-thaw process does not cause consequential mechanical or structural changes. We have recently quantified multiscale tendon mechanics and damage mechanisms using previously frozen tissue, where damage was defined as an irreversible change in the microstructure that alters the macroscopic mechanical parameters. Because freezing has been shown to alter tendon microstructures, the objective of this study was to determine if freezing alters tendon multiscale mechanics and damage mechanisms. Multiscale testing using a protocol that was designed to evaluate tendon damage (tensile stress-relaxation followed by unloaded recovery) was performed on fresh and previously frozen rat tail tendon fascicles. At both the fascicle and fibril levels, there was no difference between the fresh and frozen groups for any of the parameters, suggesting that there is no effect of freezing on tendon mechanics. After unloading, the microscale fibril strain fully recovered, and interfibrillar sliding only partially recovered, suggesting that the tendon damage is localized to the interfibrillar structures and that mechanisms of damage are the same in both fresh and previously frozen tendons. © 2017 New York Academy of Sciences.

Medial versus lateral supraspinatus tendon properties: implications for double-row rotator cuff repair.

PubMed

Wang, Vincent M; Wang, Fan Chia; McNickle, Allison G; Friel, Nicole A; Yanke, Adam B; Chubinskaya, Susan; Romeo, Anthony A; Verma, Nikhil N; Cole, Brian J

2010-12-01

Rotator cuff repair retear rates range from 25% to 90%, necessitating methods to improve repair strength. Although numerous laboratory studies have compared single-row with double-row fixation properties, little is known regarding regional (ie, medial vs lateral) suture retention properties in intact and torn tendons. A torn supraspinatus tendon will have reduced suture retention properties on the lateral aspect of the tendon compared with the more medial musculotendinous junction. Controlled laboratory study. Human supraspinatus tendons (torn and intact) were randomly assigned for suture retention mechanical testing, ultrastructural collagen fibril analysis, or histologic testing after suture pullout testing. For biomechanical evaluation, sutures were placed either at the musculotendinous junction (medial) or 10 mm from the free margin (lateral), and tendons were elongated to failure. Collagen fibril assessments were performed using transmission electron microscopy. Intact tendons showed no regional differences with respect to suture retention properties. In contrast, among torn tendons, the medial region exhibited significantly higher stiffness and work values relative to the lateral region. For the lateral region, work to 10-mm displacement (1592 ± 261 N-mm) and maximum load (265 ± 44 N) for intact tendons were significantly higher (P < .05) than that of torn tendons (1086 ± 388 N-mm and 177 ± 71 N, respectively). For medial suture placement, maximum load, stiffness, and work of intact and torn tendons were similar (P > .05). Regression analyses for the intact and torn groups revealed generally low correlations between donor age and the 3 biomechanical indices. For both intact and torn tendons, the mean fibril diameter and area density were greater in the medial region relative to the lateral (P ≤ .05). In the lateral tendon, but not the medial region, torn specimens showed a significantly lower fibril area fraction (48.3% ± 3.8%) than intact specimens (56.7% ± 3.6%, P < .05). Superior pullout resistance of medially placed sutures may provide a strain shielding effect for the lateral row after double-row repair. Larger diameter collagen fibrils as well as greater fibril area fraction in the medial supraspinatus tendon may provide greater resistance to suture migration. While clinical factors such as musculotendinous integrity warrant strong consideration for surgical decision making, the present ultrastructural and biomechanical results appear to provide a scientific rationale for double-row rotator cuff repair where sutures are placed more medially at the muscle-tendon junction.

Achilles Pain.

ERIC Educational Resources Information Center

Connors, G. Patrick

Five ailments which can cause pain in the achilles tendon area are: (1) muscular strain, involving the stretching or tearing of muscle or tendon fibers; (2) a contusion, inflammation or infection called tenosynovitis; (3) tendonitis, the inflammation of the tendon; (4) calcaneal bursitis, the inflammation of the bursa between the achilles tendon…

The Tendon Structure Returns to Asymptomatic Values in Nonoperatively Treated Achilles Tendinopathy but Is Not Associated With Symptoms: A Prospective Study.

PubMed

de Jonge, Suzan; Tol, Johannes L; Weir, Adam; Waarsing, Jan H; Verhaar, Jan A N; de Vos, Robert-Jan

2015-12-01

Tendinopathy is characterized by alterations in the tendon structure, but there are conflicting results on the potential of tendon structure normalization and no large studies on the quantified, ultrasonographic tendon structure and its association with symptoms. To determine whether the tendon structure returns to values of asymptomatic individuals after treatment with 2 substances injected within the tendon, to assess the association between the tendon structure and symptoms, and to assess the prognostic value of the baseline tendon structure on treatment response. Cohort study; Level of evidence, 2. This study was part of a randomized trial on chronic midportion Achilles tendinopathy using eccentric exercises with either a platelet-rich plasma or saline injection. Symptoms were recorded using the Victorian Institute of Sports Assessment-Achilles (VISA-A) questionnaire. The tendon structure was quantified with ultrasound tissue characterization (UTC); echo types I + II (as a percentage of total tendon types I-IV) are structure related. Follow-up was at 6, 12, 24, and 52 weeks. A control group of asymptomatic subjects (similar age) was selected to compare the tendon structure. Patient symptoms were correlated with the tendon structure using a linear model. Fifty-four patients were included in the symptomatic group. The mean (± SD) echo types I + II in the symptomatic group increased significantly from 74.6% ± 10.8% at baseline to 85.6% ± 6.0% at 24-week follow-up. The result for echo types I + II at 24 weeks was not significantly different (P = .198) from that of the asymptomatic control group (87.5% ± 6.0%). In 54 repeated measurements at 5 time points, the adjusted percentage of echo types I + II was not associated with the VISA-A score (main effect: β = .12; 95% CI, -0.12 to 0.35; P = .338). The adjusted baseline echo types I + II were not associated with a change in the VISA-A score from baseline to 52 weeks (β = -.15; 95% CI, -0.67 to 0.36; P = .555). In symptomatic, tendinopathic Achilles tendons, the ultrasonographic tendon structure improved during nonoperative treatment and normalized after 24 weeks to values of matched asymptomatic controls. There was no association between the tendon structure and symptoms. The percentage of echo types I + II before treatment was not associated with change in symptoms over time. This study demonstrates that restoration of the tendon structure is not required for an improvement of symptoms. © 2015 The Author(s).

Rat supraspinatus muscle atrophy after tendon detachment.

PubMed

Barton, Elisabeth R; Gimbel, Jonathan A; Williams, Gerald R; Soslowsky, Louis J

2005-03-01

Rotator cuff tears are one of the most common tendon disorders found in the healthy population. Tendon tears not only affect the biomechanical properties of the tendon, but can also lead to debilitation of the muscles attached to the damaged tendons. The changes that occur in the muscle after tendon detachment are not well understood. A rat rotator cuff model was utilized to determine the time course of changes that occur in the supraspinatus muscle after tendon detachment. It was hypothesized that the lack of load on the supraspinatus muscle would cause a significant decrease in muscle mass and a conversion of muscle fiber properties toward those of fast fiber types. Tendons were detached at the insertion on the humerus without repair. Muscle mass, morphology and fiber properties were measured at one, two, four, eight, and 16 weeks after detachment. Tendon detachment resulted in a rapid loss of muscle mass, an increase in the proportion of fast muscle fibers, and an increase in the fibrotic content of the muscle bed, concomitant with the appearance of adhesions of the tendon to surrounding surfaces. At 16 weeks post-detachment, muscle mass and the fiber properties in the deep muscle layers returned to normal levels. However, the fiber shifts observed in the superficial layers persisted throughout the experiment. These results suggest that load returned to the muscle via adhesions to surrounding surfaces, which may be sufficient to reverse changes in muscle mass.

Muscle-tendon glucose uptake in Achilles tendon rupture and tendinopathy before and after eccentric rehabilitation: Comparative case reports.

PubMed

Masood, Tahir; Kalliokoski, Kari; Bojsen-Møller, Jens; Finni, Taija

2016-09-01

Achilles tendon rupture (ATR) is the most common tendon rupture injury. The consequences of ATR on metabolic activity of the Achilles tendon and ankle plantarflexors are unknown. Furthermore, the effects of eccentric rehabilitation on metabolic activity patterns of Achilles tendon and ankle plantarflexors in ATR patients have not been reported thus far. We present a case study demonstrating glucose uptake (GU) in the Achilles tendon, the triceps surae, and the flexor hallucis longus of a post-surgical ATR patient before and after a 5-month eccentric rehabilitation. At baseline, three months post-surgery, all muscles and Achilles tendon displayed much higher GU in the ATR patient compared to a healthy individual despite lower plantarflexion force. After the rehabilitation, plantarflexion force increased in the operated leg while muscle GU was considerably reduced. The triceps surae muscles showed similar values to the healthy control. When compared to the healthy or a matched patient with Achilles tendon pain after 12 weeks of rehabilitation, Achilles tendon GU levels of ATR patient remained greater after the rehabilitation. Past studies have shown a shift in the metabolic fuel utilization towards glycolysis due to immobilization. Further research, combined with immuno-histological investigation, is needed to fully understand the mechanism behind excessive glucose uptake in ATR cases. Copyright © 2015 Elsevier Ltd. All rights reserved.

Enhancing the Biomechanical Performance of Anisotropic Nanofibrous Scaffolds in Tendon Tissue Engineering: Reinforcement with Cellulose Nanocrystals.

PubMed

Domingues, Rui M A; Chiera, Silvia; Gershovich, Pavel; Motta, Antonella; Reis, Rui L; Gomes, Manuela E

2016-06-01

Anisotropically aligned electrospun nanofibrous scaffolds based on natural/synthetic polymer blends have been established as a reasonable compromise between biological and biomechanical performance for tendon tissue engineering (TE) strategies. However, the limited tensile properties of these biomaterials restrict their application in this field due to the load-bearing nature of tendon/ligament tissues. Herein, the use of cellulose nanocrystals (CNCs) as reinforcing nanofillers in aligned electrospun scaffolds based on a natural/synthetic polymer blend matrix, poly-ε-caprolactone/chitosan (PCL/CHT) is reported. The incorporation of small amounts of CNCs (up to 3 wt%) into tendon mimetic nanofiber bundles has a remarkable biomaterial-toughing effect (85% ± 5%, p < 0.0002) and raises the scaffolds mechanical properties to tendon/ligament relevant range (σ = 39.3 ± 1.9 MPa and E = 540.5 ± 83.7 MPa, p < 0.0001). Aligned PCL/CHT/CNC nanocomposite fibrous scaffolds meet not only the mechanical requirements for tendon TE applications but also provide tendon mimetic extracellular matrix (ECM) topographic cues, a key feature for maintaining tendon cell's morphology and behavior. The strategy proposed here may be extended to other anisotropic aligned nanofibrous scaffolds based on natural/synthetic polymer blends and enable the full exploitation of the advantages provided by their tendon mimetic fibrous structures in tendon TE. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Marked innervation but also signs of nerve degeneration in between the Achilles and plantaris tendons and presence of innervation within the plantaris tendon in midportion Achilles tendinopathy

PubMed Central

Spang, C.; Harandi, V.M.; Alfredson, H.; Forsgren, S.

2015-01-01

Objectives: The plantaris tendon is increasingly recognised as an important factor in midportion Achilles tendinopathy. Its innervation pattern is completely unknown. Methods: Plantaris tendons (n=56) and associated peritendinous tissue from 46 patients with midportion Achilles tendinopathy and where the plantaris tendon was closely related to the Achilles tendon were evaluated. Morphological evaluations and stainings for nerve markers [general (PGP9.5), sensory (CGRP), sympathetic (TH)], glutamate NMDA receptor and Schwann cells (S-100β) were made. Results: A marked innervation, as evidenced by evaluation for PGP9.5 reactions, occurred in the peritendinous tissue located between the plantaris and Achilles tendons. It contained sensory and to some extent sympathetic and NMDAR1-positive axons. There was also an innervation in the zones of connective tissue within the plantaris tendons. Interestingly, some of the nerve fascicles showed a partial lack of axonal reactions. Conclusion: New information on the innervation patterns for the plantaris tendon in situations with midportion Achilles tendinopathy has here been obtained. The peritendinous tissue was found to be markedly innervated and there was also innervation within the plantaris tendon. Furthermore, axonal degeneration is likely to occur. Both features should be further taken into account when considering the relationship between the nervous system and tendinopathy. PMID:26032213

Spontaneous tendon rupture in systemic lupus erythematosus: association with Jaccoud's arthropathy.

PubMed

Alves, E M; Macieira, J C; Borba, E; Chiuchetta, F A; Santiago, M B

2010-03-01

Tendon rupture has rarely been described in patients with systemic lupus erythematosus. From observation of three cases of Jaccoud's arthropathy with tendon rupture, and considering that this arthropathy is more related to an inflammatory process of the tendon sheath than to synovitis per se, the intention of this study was to review the cases of tendon rupture in patients with systemic lupus erythematosus, in the hope of determining the frequency of Jaccoud's arthropathy associated with this complication. Systematic review using MEDLINE, Scielo and LILACS databases (1966 to 2009) and the following keywords: systemic lupus erythematosus, tendon rupture, Jaccoud's arthropathy. Secondary references were additionally obtained. Additionally, three Brazilian systemic lupus erythematosus patients who developed tendon rupture are described. Only 40 articles obtained fulfilled the previously established criteria. They were all case reports; the number of cases reported was 52 which, together with the three cases presented herein add up to 55 cases. Forty-six patients were women aged between 19 and 71 years, with a mean age of 40.1 +/- 12.4 years, and the average duration of the disease was 10 years. The most frequently observed rupture sites were the patellar and Achilles' tendons. While almost all patients described were on various doses of corticosteroids, 16 patients concomitantly had Jaccoud's arthropathy (29%). In conclusion, the association between Jaccoud's arthropathy and tendon rupture in systemic lupus erythematosus has been underestimated. As almost one-third of the systemic lupus erythematosus patients with tendon rupture also have Jaccoud's arthropathy, this arthropathy may be recognized as risk marker for tendon rupture.

Different Achilles Tendon Pathologies Show Distinct Histological and Molecular Characteristics

PubMed Central

Minkwitz, Susann; Schmock, Aysha; Bormann, Nicole; Kurtoglu, Alper; Tsitsilonis, Serafeim; Manegold, Sebastian

2018-01-01

Reasons for the development of chronic tendon pathologies are still under debate and more basic knowledge is needed about the different diseases. The aim of the present study was therefore to characterize different acute and chronic Achilles tendon disorders. Achilles tendon samples from patients with chronic tendinopathy (n = 7), chronic ruptures (n = 6), acute ruptures (n = 13), and intact tendons (n = 4) were analyzed. The histological score investigating pathological changes was significantly increased in tendinopathy and chronic ruptures compared to acute ruptures. Inflammatory infiltration was detected by immunohistochemistry in all tendon pathology groups, but was significantly lower in tendinopathy compared to chronic ruptures. Quantitative real-time PCR (qRT-PCR) analysis revealed significantly altered expression of genes related to collagens and matrix modeling/remodeling (matrix metalloproteinases, tissue inhibitors of metalloproteinases) in tendinopathy and chronic ruptures compared to intact tendons and/or acute ruptures. In all three tendon pathology groups markers of inflammation (interleukin (IL) 1β, tumor necrosis factor α, IL6, IL10, IL33, soluble ST2, transforming growth factor β1, cyclooxygenase 2), inflammatory cells (cluster of differentaition (CD) 3, CD68, CD80, CD206), fat metabolism (fatty acid binding protein 4, peroxisome proliferator-activated receptor γ, CCAAT/enhancer-binding protein α, adiponectin), and innervation (protein gene product 9.5, growth associated protein 43, macrophage migration inhibitory factor) were detectable, but only in acute ruptures significantly regulated compared to intact tendons. The study gives an insight into structural and molecular changes of pathological processes in tendons and might be used to identify targets for future therapy of tendon pathologies. PMID:29385715

The interfascicular matrix enables fascicle sliding and recovery in tendon, and behaves more elastically in energy storing tendons

PubMed Central

Thorpe, Chavaunne T.; Godinho, Marta S.C.; Riley, Graham P.; Birch, Helen L.; Clegg, Peter D.; Screen, Hazel R.C.

2015-01-01

While the predominant function of all tendons is to transfer force from muscle to bone and position the limbs, some tendons additionally function as energy stores, reducing the cost of locomotion. Energy storing tendons experience extremely high strains and need to be able to recoil efficiently for maximum energy storage and return. In the equine forelimb, the energy storing superficial digital flexor tendon (SDFT) has much higher failure strains than the positional common digital extensor tendon (CDET). However, we have previously shown that this is not due to differences in the properties of the SDFT and CDET fascicles (the largest tendon subunits). Instead, there is a greater capacity for interfascicular sliding in the SDFT which facilitates the greater extensions in this particular tendon (Thorpe et al., 2012). In the current study, we exposed fascicles and interfascicular matrix (IFM) from the SDFT and CDET to cyclic loading followed by a test to failure. The results show that IFM mechanical behaviour is not a result of irreversible deformation, but the IFM is able to withstand cyclic loading, and is more elastic in the SDFT than in the CDET. We also assessed the effect of ageing on IFM properties, demonstrating that the IFM is less able to resist repetitive loading as it ages, becoming stiffer with increasing age in the SDFT. These results provide further indications that the IFM is important for efficient function in energy storing tendons, and age-related alterations to the IFM may compromise function and predispose older tendons to injury. PMID:25958330

Manipulation of Foot Strike and Footwear Increases Achilles Tendon Loading During Running.

PubMed

Rice, Hannah; Patel, Mubarak

2017-08-01

The Achilles tendon is the most common site of tendon overuse injury in humans. Running with a forefoot strike pattern and in minimal shoes is a topic of recent interest, yet evidence is currently limited regarding the combined influence of foot strike and footwear on Achilles tendon loading. To investigate the influence of both foot strike and footwear on Achilles tendon loading in habitual rearfoot strike runners. Controlled laboratory study. Synchronized kinematic and force data were collected from 22 habitual rearfoot strikers (11 male), who habitually ran in nonminimal running shoes, during overground running at 3.6 m·s -1 . Participants ran in 3 different footwear conditions (standard running shoe, minimal running shoe, and barefoot) with both a rearfoot strike (RFS) and an imposed forefoot strike (FFS) in each footwear condition. Achilles tendon loading was estimated by use of inverse dynamics, where the Achilles tendon moment arm was determined with a regression equation. A 2-way, repeated-measures analysis of variance was used to compare conditions. Achilles tendon impulse was greater when subjects ran with an FFS rather than an RFS in minimal shoes. Achilles tendon loading rates were higher when subjects ran either in minimal shoes or barefoot than in standard shoes, regardless of foot strike. In runners who habitually rearfoot strike in standard running shoes, running in minimal shoes or barefoot increased the rate of tendon loading, and running with a forefoot strike in minimal shoes increased the magnitude of tendon loading. Transitioning to these running conditions may increase the risk of tendinopathy.

Lack of tissue renewal in human adult Achilles tendon is revealed by nuclear bomb 14C

PubMed Central

Heinemeier, Katja Maria; Schjerling, Peter; Heinemeier, Jan; Magnusson, Stig Peter; Kjaer, Michael

2013-01-01

Tendons are often injured and heal poorly. Whether this is caused by a slow tissue turnover is unknown, since existing data provide diverging estimates of tendon protein half-life that range from 2 mo to 200 yr. With the purpose of determining life-long turnover of human tendon tissue, we used the 14C bomb-pulse method. This method takes advantage of the dramatic increase in atmospheric levels of 14C, produced by nuclear bomb tests in 1955–1963, which is reflected in all living organisms. Levels of 14C were measured in 28 forensic samples of Achilles tendon core and 4 skeletal muscle samples (donor birth years 1945–1983) with accelerator mass spectrometry (AMS) and compared to known atmospheric levels to estimate tissue turnover. We found that Achilles tendon tissue retained levels of 14C corresponding to atmospheric levels several decades before tissue sampling, demonstrating a very limited tissue turnover. The tendon concentrations of 14C approximately reflected the atmospheric levels present during the first 17 yr of life, indicating that the tendon core is formed during height growth and is essentially not renewed thereafter. In contrast, 14C levels in muscle indicated continuous turnover. Our observation provides a fundamental premise for understanding tendon function and pathology, and likely explains the poor regenerative capacity of tendon tissue.—Heinemeier, K. M., Schjerling, P., Heinemeier, J., Magnusson, S. P., Kjaer, M. Lack of tissue renewal in human adult Achilles tendon is revealed by nuclear bomb 14C. PMID:23401563

Rotator cuff tendon connections with the rotator cable.

PubMed

Rahu, Madis; Kolts, Ivo; Põldoja, Elle; Kask, Kristo

2017-07-01

The literature currently contains no descriptions of the rotator cuff tendons, which also describes in relation to the presence and characteristics of the rotator cable (anatomically known as the ligamentum semicirculare humeri). The aim of the current study was to elucidate the detailed anatomy of the rotator cuff tendons in association with the rotator cable. Anatomic dissection was performed on 21 fresh-frozen shoulder specimens with an average age of 68 years. The rotator cuff tendons were dissected from each other and from the glenohumeral joint capsule, and the superior glenohumeral, coracohumeral, coracoglenoidal and semicircular (rotator cable) ligaments were dissected. Dissection was performed layer by layer and from the bursal side to the joint. All ligaments and tendons were dissected in fine detail. The rotator cable was found in all specimens. It was tightly connected to the supraspinatus (SSP) tendon, which was partly covered by the infraspinatus (ISP) tendon. The posterior insertion area of the rotator cable was located in the region between the middle and inferior facets of the greater tubercle of the humerus insertion areas for the teres minor (TM), and ISP tendons were also present and fibres from the SSP extended through the rotator cable to those areas. The connection between the rotator cable and rotator cuff tendons is tight and confirms the suspension bridge theory for rotator cuff tears in most areas between the SSP tendons and rotator cable. In its posterior insertion area, the rotator cable is a connecting structure between the TM, ISP and SSP tendons. These findings might explain why some patients with relatively large rotator cuff tears can maintain seamless shoulder function.

Is there still a place for Achilles tendon lengthening?

PubMed

Tagoe, Mark T; Reeves, Neil D; Bowling, Frank L

2016-01-01

Patients with diabetes and ankle equinus are at particularly high risk for forefoot ulceration because of the development of high forefoot pressures. Stiffness in the triceps surae muscles and tendons are thought to be largely responsible for equinus in patients with diabetes and underpins the surgical rationale for Achilles tendon lengthening (ATL) procedures to alleviate this deformity and reduce ulcer risk. The established/traditional surgical approach is the triple hemisection along the length of the Achilles tendon. Although the percutaneous approach has been successful in achieving increases in ankle dorsiflexion >30°, the tendon rupture risk has led to some surgeons looking at alternative approaches. The gastrocnemius aponeurosis may be considered as an alternative because of the Achilles tendon's poor blood supply. ATL procedures are a balance between achieving adequate tendon lengthening and minimizing tendon rupture risk during or after surgery. After ATL surgery, the first 7 days should involve reduced loading and protected range of motion to avoid rupture, after which gradual reintroduction to loading should be encouraged to increase tendon strength. In summary, there is a moderate level of evidence to support surgical intervention for ankle joint equinus in patients with diabetes and forefoot ulceration that is non-responsive to other conservative treatments. Areas of caution for ATL procedures include the risk for overcorrection, tendon rupture and the tendon's poor blood supply. Further prospective randomized control trials are required to confirm the benefits of ATL procedures over conservative care and the most optimal anatomical sites for surgical intervention. Copyright © 2016 John Wiley & Sons, Ltd.

21 CFR 888.3025 - Passive tendon prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Passive tendon prosthesis. 888.3025 Section 888...) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3025 Passive tendon prosthesis. (a) Identification. A passive tendon prosthesis is a device intended to be implanted made of silicon elastomer or a...

21 CFR 888.3025 - Passive tendon prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Passive tendon prosthesis. 888.3025 Section 888...) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3025 Passive tendon prosthesis. (a) Identification. A passive tendon prosthesis is a device intended to be implanted made of silicon elastomer or a...

Free Bone Plug Quadriceps Tendon Harvest and Suspensory Button Attachment for Anterior Cruciate Ligament Reconstruction.

PubMed

Todor, Adrian; Caterev, Sergiu; Nistor, Dan Viorel; Khallouki, Youssef

2016-06-01

The most commonly used autografts for anterior cruciate ligament reconstruction are the bone-patellar tendon-bone and hamstring tendons. Each has its advantages and limitations. The bone-patellar tendon-bone autograft can lead to more donor-site morbidity, and the hamstring autograft can be unpredictable in size. The quadriceps tendon, with or without a bone block, has been described as an alternative graft source and has been used especially in revision cases, but in recent years, it has attracted attention even for primary cases. We report a technique for harvesting a free bone quadriceps tendon graft and attaching an extracortical button for femoral fixation for anterior cruciate ligament reconstruction.

Force Model for Control of Tendon Driven Hands

NASA Technical Reports Server (NTRS)

Pena, Edward; Thompson, David E.

1997-01-01

Knowing the tendon forces generated for a given task such as grasping via a model, an artificial hand can be controlled. A two-dimensional force model for the index finger was developed. This system is assumed to be in static equilibrium, therefore, the equations of equilibrium were applied at each joint. Constraint equations describing the tendon branch connectivity were used. Gaussian elimination was used to solve for the unknowns of the Linear system. Results from initial work on estimating tendon forces in post-operative hands during active motion therapy were discussed. The results are important for understanding the effects of hand position on tendon tension, elastic effects on tendon tension, and overall functional anatomy of the hand.

The role of animal models in tendon research

PubMed Central

Hast, M. W.; Zuskov, A.; Soslowsky, L. J.

2014-01-01

Tendinopathy is a debilitating musculoskeletal condition which can cause significant pain and lead to complete rupture of the tendon, which often requires surgical repair. Due in part to the large spectrum of tendon pathologies, these disorders continue to be a clinical challenge. Animal models are often used in this field of research as they offer an attractive framework to examine the cascade of processes that occur throughout both tendon pathology and repair. This review discusses the structural, mechanical, and biological changes that occur throughout tendon pathology in animal models, as well as strategies for the improvement of tendon healing. Cite this article: Bone Joint Res 2014;3:193–202. PMID:24958818

A Comparative Study of Clinical Outcomes and Second-Look Arthroscopic Findings between Remnant-Preserving Tibialis Tendon Allograft and Hamstring Tendon Autograft in Anterior Cruciate Ligament Reconstruction: Matched-Pair Design.

PubMed

Kim, You Keun; Ahn, Jong Hyun; Yoo, Jae Doo

2017-12-01

This study aimed to compare stability, functional outcome, and second-look arthroscopic findings after anterior cruciate ligament reconstruction between remnant-preserving tibialis tendon allograft and remnant-sacrificing hamstring tendon autograft. We matched two groups (remnant-preserving tibialis tendon allograft group and hamstring tendon autograft group) in terms of demographic characteristics, associated injury, and knee characteristics. Each group consisted of 25 patients. Operation time was longer in the remnant-preserving tibialis tendon allograft group, but there was no significant intergroup difference in stability, clinical outcome, and second-look arthroscopic findings. When an autograft is not feasible in anterior cruciate ligament reconstruction, the remnant-preserving technique can produce comparable results in terms of restoration of function, stability of the knee, and degree of synovium coverage at second-look arthroscopy compared to remnant-sacrificing hamstring autograft.

A passive exoskeleton with artificial tendons: design and experimental evaluation.

PubMed

van Dijk, Wietse; van der Kooij, Herman; Hekman, Edsko

2011-01-01

We developed a passive exoskeleton that was designed to minimize joint work during walking. The exoskeleton makes use of passive structures, called artificial tendons, acting in parallel with the leg. Artificial tendons are elastic elements that are able to store and redistribute energy over the human leg joints. The elastic characteristics of the tendons have been optimized to minimize the mechanical work of the human leg joints. In simulation the maximal reduction was 40 percent. The performance of the exoskeleton was evaluated in an experiment in which nine subjects participated. Energy expenditure and muscle activation were measured during three conditions: Normal walking, walking with the exoskeleton without artificial tendons, and walking with the exoskeleton with the artificial tendons. Normal walking was the most energy efficient. While walking with the exoskeleton, the artificial tendons only resulted in a negligibly small decrease in energy expenditure. © 2011 IEEE

Effects of foot orthoses on Achilles tendon load in recreational runners.

PubMed

Sinclair, J; Isherwood, J; Taylor, P J

2014-09-01

Achilles tendon pathology is a frequently occurring musculoskeletal disorder in runners. Foot orthoses have been shown to reduce the symptoms of pain in runners but their mechanical effects are still not well understood. This study aimed to examine differences in Achilles tendon load when running with and without orthotic intervention. Twelve male runners ran at 4.0 m·s(-1). Ankle joint moments and Achilles tendon forces were compared when running with and without orthotics. The results indicate that running with foot orthotics was associated with significant reductions in Achilles tendon load compared to without orthotics. In addition to providing insight into the mechanical effects of orthotics in runners, the current investigation suggests that via reductions in Achilles tendon load, foot orthoses may serve to reduce the incidence of chronic Achilles tendon pathologies in runners. Copyright © 2014 Elsevier Ltd. All rights reserved.

Applied Joint-Space Torque and Stiffness Control of Tendon-Driven Fingers

NASA Technical Reports Server (NTRS)

Abdallah, Muhammad E.; Platt, Robert, Jr.; Wampler, Charles W.; Hargrave, Brian

2010-01-01

Existing tendon-driven fingers have applied force control through independent tension controllers on each tendon, i.e. in the tendon-space. The coupled kinematics of the tendons, however, cause such controllers to exhibit a transient coupling in their response. This problem can be resolved by alternatively framing the controllers in the joint-space of the manipulator. This work presents a joint-space torque control law that demonstrates both a decoupled and significantly faster response than an equivalent tendon-space formulation. The law also demonstrates greater speed and robustness than comparable PI controllers. In addition, a tension distribution algorithm is presented here to allocate forces from the joints to the tendons. It allocates the tensions so that they satisfy both an upper and lower bound, and it does so without requiring linear programming or open-ended iterations. The control law and tension distribution algorithm are implemented on the robotic hand of Robonaut-2.

The use of Achilles tendon allograft for latissimus dorsi tendon reconstruction: a minimally invasive technique.

PubMed

Sabzevari, Soheil; Chao, Tom; Kalawadia, Jay; Lin, Albert

2018-01-01

Treatment of subacute, retracted latissimus dorsi and teres major tendon ruptures in young overhead athletes is challenging. This case report describes management of a subacute retracted latissimus dorsi and teres major rupture with Achilles tendon allograft reconstruction using a two-incision minimally invasive technique. Level of evidence V.

THE ROLE OF MECHANOBIOLOGY IN TENDON HEALING

PubMed Central

Killian, Megan L.; Cavinatto, Leonardo; Galatz, Leesa M.; Thomopoulos, Stavros

2011-01-01

Mechanical cues affect tendon healing, homeostasis, and development in a variety of settings. Alterations in the mechanical environment are known to result in changes in the expression of extracellular matrix proteins, growth factors, transcription factors, and cytokines that can alter tendon structure and cell viability. Loss of muscle force in utero or in the immediate postnatal period delays tendon and enthesis development. The response of healing tendons to mechanical load varies depending on anatomic location. Flexor tendons require motion to prevent adhesion formation, yet excessive force results in gap formation and subsequent weakening of the repair. Excessive motion in the setting of anterior cruciate ligament reconstruction causes accumulation of macrophages, which are detrimental to tendon graft healing. Complete removal of load is detrimental to rotator cuff healing, yet large forces are also harmful. Controlled loading can enhance healing in most settings; however, a fine balance must be reached between loads that are too low (leading to a catabolic state) and too high (leading to micro-damage). This review will summarize existing knowledge of the mechanobiology of tendon development, homeostasis, and healing. PMID:22244066

Cell-laden composite suture threads for repairing damaged tendons.

PubMed

Costa-Almeida, Raquel; Domingues, Rui M A; Fallahi, Afsoon; Avci, Huseyin; Yazdi, Iman K; Akbari, Mohsen; Reis, Rui L; Tamayol, Ali; Gomes, Manuela E; Khademhosseini, Ali

2018-04-01

Tendons have limited regenerative capacity due to their low cellularity and hypovascular nature, which results in poor clinical outcomes of presently used therapies. As tendon injuries are often observed in active adults, it poses an increasing socio-economic burden on healthcare systems. Currently, suture threads are used during surgical repair to anchor the tissue graft or to connect injured ends. Here, we created composite suture threads coated with a layer of cell-laden hydrogel that can be used for bridging the injured tissue aiming at tendon regeneration. In addition, the fibres can be used to engineer 3-dimensional constructs through textile processes mimicking the architecture and mechanical properties of soft tissues, including tendons and ligaments. Encapsulated human tendon-derived cells migrated within the hydrogel and aligned at the surface of the core thread. An up-regulation of tendon-related genes (scleraxis and tenascin C) and genes involved in matrix remodelling (matrix metalloproteinases 1, matrix metalloproteinases 2) was observed. Cells were able to produce a collagen-rich matrix, remodelling their micro-environment, which is structurally comparable to native tendon tissue. Copyright © 2017 John Wiley & Sons, Ltd.

Surgical treatment for partial rupture of the distal biceps tendon using palmaris longus tendon graft: A case report.

PubMed

Ozasa, Yasuhiro; Wada, Takuro; Iba, Kousuke; Yamashita, Toshihiko

2018-03-08

We report a case of a partial rupture of the distal biceps tendon that was surgically treated using a palmaris longus tendon graft. A 58-year-old man complained of increasing pain with resisted elbow flexion and supination in the antecubital fossa. Magnetic resonance imaging revealed the irregularity of a distal attachment of the biceps brachii and peripheral signal changes. We diagnosed a partial rupture of the distal biceps tendon. Because conservative treatment failed, surgical treatment was performed through a single anterior approach. The insertion of the tendon was partially ruptured at the radial tuberosity. After the involved site was debrided, the palmaris longus tendon was grafted with suture anchors to reinforce the remaining tendon. Postoperative immobilization was not performed, and all moves were freed after 3 weeks. At the 6-year postoperative follow-up, the patient no longer experienced pain and returned to his original job without any limitations. Copyright © 2018 Turkish Association of Orthopaedics and Traumatology. Production and hosting by Elsevier B.V. All rights reserved.

[Application of silk-based tissue engineering scaffold for tendon / ligament regeneration].

PubMed

Hu, Yejun; Le, Huihui; Jin, Zhangchu; Chen, Xiao; Yin, Zi; Shen, Weiliang; Ouyang, Hongwei

2016-03-01

Tendon/ligament injury is one of the most common impairments in sports medicine. The traditional treatments of damaged tissue repair are unsatisfactory, especially for athletes, due to lack of donor and immune rejection. The strategy of tissue engineering may break through these limitations, and bring new hopes to tendon/ligament repair, even regeneration. Silk is a kind of natural biomaterials, which has good biocompatibility, wide range of mechanical properties and tunable physical structures; so it could be applied as tendon/ligament tissue engineering scaffolds. The silk-based scaffold has robust mechanical properties; combined with other biological ingredients, it could increase the surface area, promote more cell adhesion and improve the biocompatibility. The potential clinical application of silk-based scaffold has been confirmed by in vivo studies on tendon/ligament repairing, such as anterior cruciate ligament, medial collateral ligament, achilles tendon and rotator cuff. To develop novel biomechanically stable and host integrated tissue engineered tendon/ligament needs more further micro and macro studies, combined with product development and clinical application, which will give new hope to patients with tendon/ligament injury.

Arthroscopic suture retrievers and shuttles: a biomechanical investigation of the force required for tendon penetration and defect size.

PubMed

Lenz, Christopher G; Wieser, Karl; Lajtai, Georg; Meyer, Dominik C

2015-11-17

To compare instruments designed for arthroscopic suture handling during arthroscopic rotator cuff repair, to assess the force needed to penetrate the tendon, and to evaluate the residual defect size. Twenty-one instruments were each tested ten times on thawed sheep infraspinatus tendons. The force needed to pierce the tendon with each instrument was measured using a custom setup. Bone wax plates were used to make the perforation marks visible and to quantify the lesions each instrument created. The force to pierce a tendon had a range of 5.6-18.5 N/mm. Within the group of suture retrievers, the angled instruments required in average 85 % higher forces than straight instruments. The lesion area had a range of 2-7 mm(2). Suture retrievers produced significantly larger lesion sizes compared with suture shuttles. For the identical task of passing a suture through a tendon, differences exist regarding the ease of tendon penetration and potential damage to the tendon for different tools. The design, function, and resulting lesion size may be relevant and important for surgical handling and to avoid excess structural damage to the tendon. These results suggest that choosing the most appropriate tools for arthroscopic suture stitching influences the ease of handling and final integrity of the tissue.

Relationship between tendon stiffness and failure: a metaanalysis

PubMed Central

LaCroix, Andrew S.; Duenwald-Kuehl, Sarah E.; Lakes, Roderic S.

2013-01-01

Tendon is a highly specialized, hierarchical tissue designed to transfer forces from muscle to bone; complex viscoelastic and anisotropic behaviors have been extensively characterized for specific subsets of tendons. Reported mechanical data consistently show a pseudoelastic, stress-vs.-strain behavior with a linear slope after an initial toe region. Many studies report a linear, elastic modulus, or Young's modulus (hereafter called elastic modulus) and ultimate stress for their tendon specimens. Individually, these studies are unable to provide a broader, interstudy understanding of tendon mechanical behavior. Herein we present a metaanalysis of pooled mechanical data from a representative sample of tendons from different species. These data include healthy tendons and those altered by injury and healing, genetic modification, allograft preparation, mechanical environment, and age. Fifty studies were selected and analyzed. Despite a wide range of mechanical properties between and within species, elastic modulus and ultimate stress are highly correlated (R2 = 0.785), suggesting that tendon failure is highly strain-dependent. Furthermore, this relationship was observed to be predictable over controlled ranges of elastic moduli, as would be typical of any individual species. With the knowledge gained through this metaanalysis, noninvasive tools could measure elastic modulus in vivo and reasonably predict ultimate stress (or structural compromise) for diseased or injured tendon. PMID:23599401

Structure-mechanics relationships in mineralized tendons.

PubMed

Spiesz, Ewa M; Zysset, Philippe K

2015-12-01

In this paper, we review the hierarchical structure and the resulting elastic properties of mineralized tendons as obtained by various multiscale experimental and computational methods spanning from nano- to macroscale. The mechanical properties of mineralized collagen fibres are important to understand the mechanics of hard tissues constituted by complex arrangements of these fibres, like in human lamellar bone. The uniaxial mineralized collagen fibre array naturally occurring in avian tendons is a well studied model tissue for investigating various stages of tissue mineralization and the corresponding elastic properties. Some avian tendons mineralize with maturation, which results in a graded structure containing two zones of distinct morphology, circumferential and interstitial. These zones exhibit different amounts of mineral, collagen, pores and a different mineral distribution between collagen fibrillar and extrafibrillar space that lead to distinct elastic properties. Mineralized tendon cells have two phenotypes: elongated tenocytes placed between fibres in the circumferential zone and cuboidal cells with lower aspect ratios in the interstitial zone. Interestingly some regions of avian tendons seem to be predestined to mineralization, which is exhibited as specific collagen cross-linking patterns as well as distribution of minor tendon constituents (like proteoglycans) and loss of collagen crimp. Results of investigations in naturally mineralizing avian tendons may be useful in understanding the pathological mineralization occurring in some human tendons. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effects of corticosteroids and hyaluronic acid on torn rotator cuff tendons in vitro and in rats.

PubMed

Nakamura, Hidehiro; Gotoh, Masafumi; Kanazawa, Tomonoshin; Ohta, Keisuke; Nakamura, Keiichirou; Honda, Hirokazu; Ohzono, Hiroki; Shimokobe, Hisao; Mitsui, Yasuhiro; Shirachi, Isao; Okawa, Takahiro; Higuchi, Fujio; Shirahama, Masahiro; Shiba, Naoto; Matsueda, Satoko

2015-10-01

Corticosteroids (CS) or hyaluronic acid (HA) is used in subacromial injection for the conservative treatment of rotator cuff tears (RCT); this study addresses the question of how CS and HA affect the tendon tissue and fibroblasts in vitro and in rats. Cell proliferation assays were performed in human tendon fibroblasts from RCT. Rats underwent surgery to create RCT, and the surgical sites were injected with CS or HA. The rotator cuff tendons were subjected to biomechanical testing, microscopic and immunohistochemical analysis of proliferating cell nuclear antigen (PCNA), and ultrastructural analysis. Cell proliferation was significantly decreased with CS in vitro (p < 0.05). Maximal load of CS-treated tendons was significantly decreased compared with that of HA-treated tendons (p < 0.05), as well as PCNA(+) cells at 2 weeks (p < 0.05). Ultrastructural observations of the CS-treated rats detected apoptosis of tendon fibroblasts 24 h after surgery. Histological and biomechanical data 4 weeks after surgery were not significant among the three groups. Unlike HA, CS caused cell death, and inhibition of the proliferation of tendon fibroblasts, leading to a delay of tendon healing involved and a subsequent decrease of biomechanical strength at the surgical site. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Viscoelastic shear lag model to predict the micromechanical behavior of tendon under dynamic tensile loading.

PubMed

Wu, Jiayu; Yuan, Hong; Li, Longyuan; Fan, Kunjie; Qian, Shanguang; Li, Bing

2018-01-21

Owing to its viscoelastic nature, tendon exhibits stress rate-dependent breaking and stiffness function. A Kelvin-Voigt viscoelastic shear lag model is proposed to illustrate the micromechanical behavior of the tendon under dynamic tensile conditions. Theoretical closed-form expressions are derived to predict the deformation and stress transfer between fibrils and interfibrillar matrix while tendon is dynamically stretched. The results from the analytical solutions demonstrate that how the fibril overlap length and fibril volume fraction affect the stress transfer and mechanical properties of tendon. We find that the viscoelastic property of interfibrillar matrix mainly results in collagen fibril failure under fast loading rate or creep rupture of tendon. However, discontinuous fibril model and hierarchical structure of tendon ensure relative sliding under slow loading rate, helping dissipate energy and protecting fibril from damage, which may be a key reason why regularly staggering alignment microstructure is widely selected in nature. According to the growth, injury, healing and healed process of tendon observed by many researchers, the conclusions presented in this paper agrees well with the experimental findings. Additionally, the emphasis of this paper is on micromechanical behavior of tendon, whereas this analytical viscoelastic shear lag model can be equally applicable to other soft or hard tissues, owning the similar microstructure. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of Tendon Stem Cells in Chitosan/β-Glycerophosphate/Collagen Hydrogel on Achilles Tendon Healing in a Rat Model.

PubMed

Yang, Zhijin; Cao, Honghui; Gao, Shang; Yang, Mingyu; Lyu, Jingtong; Tang, Kanglai

2017-09-27

BACKGROUND The aim of this study was to determine whether the local application of tendon stem cells (TSCs) with chitosan/β-glycerophosphate/collagen(C/GP/Co) hydrogel promotes healing after an acute Achilles tendon injury in a rat model. MATERIAL AND METHODS Ninety-six Sprague-Dawley (SD) rats were used to make an Achilles tendon defect model, then the animals were randomly divided into 4 groups consisting of 8 rats each: control group, hydrogel group, TSCs group, and TSCs with hydrogel group. At 2, 4, and 6 weeks after treatment, tendon samples were harvested, and the quality of tendon repair was evaluated based on histology, immunohistochemistry, and biomechanical properties. RESULTS Combining TSCs with C/GP/Co hydrogel significantly enhances tendon healing compared with the control, hydrogel, and TSCs groups. The improved healing was indicated by the improvement in histological and immunohistochemistry outcomes and the increase in the biomechanical properties of the regenerated tissue at both 4 and 6 weeks post-injury. CONCLUSIONS This study demonstrates that the transplantation of TSCs combined with C/GP/Co hydrogel significantly improved the histological, immunohistochemistry, and biomechanical outcomes of the regenerated tissue at 4 and 6 weeks after implantation. TSCs with C/GP/Co hydrogel is a potentially effective treatment for tendon injury.

Preinjury and postinjury running analysis along with measurements of strength and tendon length in a patient with a surgically repaired Achilles tendon rupture.

PubMed

Silbernagel, Karin Grävare; Willy, Richard; Davis, Irene

2012-06-01

Case report. The Achilles tendon is the most frequently ruptured tendon, and the incidence of Achilles tendon rupture has increased in the last decade. The rupture generally occurs without any preceding warning signs, and therefore preinjury data are seldom available. This case represents a unique opportunity to compare preinjury running mechanics with postinjury evaluation in a patient with an Achilles tendon rupture. A 23-year-old female sustained a right complete Achilles tendon rupture while playing soccer. Running mechanics data were collected preinjury, as she was a healthy participant in a study on running analysis. In addition, patient-reported symptoms, physical activity level, strength, ankle range of motion, heel-rise ability, Achilles tendon length, and running kinetics were evaluated 1 year after surgical repair. During running, greater ankle dorsiflexion and eversion and rearfoot abduction were noted on the involved side postinjury when compared to preinjury data. In addition, postinjury, the magnitude of all kinetics data was lower on the involved limb when compared to the uninvolved limb. The involved side displayed differences in strength, ankle range of motion, heel rise, and tendon length when compared to the uninvolved side 1 year after injury. Despite a return to normal running routine and reports of only minor limitations with running, considerable changes were noted in running biomechanics 1 year after injury. Calf muscle weakness and Achilles tendon elongation were also found when comparing the involved and uninvolved sides.

Rupture of the anterior tibial tendon: three clinical cases, anatomical study, and literature review.

PubMed

Anagnostakos, Konstantinos; Bachelier, Felix; Fürst, Oliver Alexander; Kelm, Jens

2006-05-01

We report three cases of anterior tibial tendon ruptures and the results of an anatomical study in regard to the tendon's insertion site and a literature review. Three patients were referred to our hospital with anterior tibial tendon ruptures. In the anatomical study, 53 feet were dissected, looking in particular for variants of the bony insertion of the tendon. Two patients had surgical treatment (one primary repair and one semimembranosus tendon graft) and one conservative treatment. After a mean followup of 14 weeks all patients had satisfactory outcomes. In the anatomical study, we noted three different insertion sites: in 36 feet the tendon inserted into the medial side of the cuneiform and the base of the first metatarsal bone and in 13 feet only into the medial side of the cuneiform bone. In the remaining four feet the tendon inserted into the cuneiform and the first metatarsal bone, but an additional tendon was noted taking its origin from the anterior tibial tendon near its insertion into the medial cuneiform and attaching to the proximal part of the first metatarsal. According to literature, surgical repair is the treatment of choice for acute ruptures and for patients with high activity levels. For chronic ruptures and patients with low demands, conservative management may lead to an equally good outcome. Knowledge of the anatomy in this region may be helpful for diagnosis and for the interpretation of intraoperative findings and choosing the most appropriate surgical procedure.

Multiple variations of the tendons of the anatomical snuffbox.

PubMed

Thwin, San San; Fazlin, Fazlin; Than, Myo

2014-01-01

Multiple tendons of the abductor pollicis longus (APL) in the anatomical snuffbox of the wrist can lead to the development of de Quervain's syndrome, which is caused by stenosing tenosynovitis. A cadaveric study was performed to establish the variations present in the tendons of the anatomical snuffbox in a Malaysian population, in the hope that this knowledge would aid clinical investigation and surgical treatment of de Quervain's tenosynovitis. Routine dissection of ten upper limbs was performed to determine the variations in the tendons of the anatomical snuffbox of the wrist. In all the dissected upper limbs, the APL tendon of the first extensor compartment was found to have several (3-14) tendon slips. The insertion of the APL tendon slips in all upper limbs were at the base of the first metacarpal bone, trapezium and fascia of the opponens pollicis muscle; however, in seven specimens, they were also found to be attached to the fleshy belly of the abductor pollicis brevis muscle. In two specimens, double tendons of the extensor pollicis longus located in the third extensor compartment were inserted into the capsule of the proximal interphalangeal joints before being joined to the extensor expansion. In two other specimens, the first extensor compartment had two osseofibrous tunnels divided by a septum that separated the APL tendon from the extensor pollicis brevis tendon. Multiple variations were found in the anatomical snuffbox region of the dissected upper limbs. Knowledge of these variations would be useful in interventional radiology and orthopaedic surgery.

Rotator Cuff Repair with a Tendon-Fibrocartilage-Bone Composite Bridging Patch

PubMed Central

Ji, Xiaoxi; Chen, Qingshan; Thoreson, Andrew R.; Qu, Jin; An, Kai-Nan; Amadio, Peter C.; Steinmann, Scott P.; Zhao, Chunfeng

2015-01-01

Background To compare the mechanical performance of a rotator cuff repaired with a novel tendon-fibrocartilage-bone composite bridging patch vs the traditional Mason-Allen repair in an in vitro canine model. Methods Twenty shoulders and 10 bridging patches from patellar tendon were harvested. The patches were trimmed and sliced into 2 layers. An infraspinatus tendon tear was created in each shoulder. Modified Mason-Allen sutures were used to repair the infraspinatus tendon to the greater tuberosity, with or without the bridging patch (bridging patch group and controls, respectively). Shoulders were loaded to failure under displacement control at a rate of 0.5mm/sec. Findings The ultimate tensile load was significantly higher in the bridging patch group than control (mean [SD], 365.46 [36.45] vs 272.79 [48.88] N; P<.001). Stiffness at the greater tuberosity repair site and the patch-infraspinatus tendon repair site was significantly higher than the control repair site (93.96 [27.72] vs 42.62 [17.48] N/mm P<.001; 65.94 [24.51] vs 42.62 [17.48] N/mm P=.02, respectively). Interpretation The tendon-fibrocartilage-bone composite bridging patch achieved higher ultimate tensile load and stiffness at the patch–greater tuberosity repair site compared with traditional repair in a canine model. This composite tissue transforms the traditional tendon-to-bone healing interface (with dissimilar tissues) into a pair of bone-to-bone and tendon-to-tendon interfaces, which may improve healing quality and reduce retear rate. PMID:26190097

Rotator cuff repair with a tendon-fibrocartilage-bone composite bridging patch.

PubMed

Ji, Xiaoxi; Chen, Qingshan; Thoreson, Andrew R; Qu, Jin; An, Kai-Nan; Amadio, Peter C; Steinmann, Scott P; Zhao, Chunfeng

2015-11-01

To compare the mechanical performance of a rotator cuff repaired with a novel tendon-fibrocartilage-bone composite bridging patch vs the traditional Mason-Allen repair in an in vitro canine model. Twenty shoulders and 10 bridging patches from patellar tendon were harvested. The patches were trimmed and sliced into 2 layers. An infraspinatus tendon tear was created in each shoulder. Modified Mason-Allen sutures were used to repair the infraspinatus tendon to the greater tuberosity, with or without the bridging patch (bridging patch group and controls, respectively). Shoulders were loaded to failure under displacement control at a rate of 0.5mm/s. The ultimate tensile load was significantly higher in the bridging patch group than control (mean [SD], 365.46 [36.45] vs 272.79 [48.88] N; P<.001). Stiffness at the greater tuberosity repair site and the patch-infraspinatus tendon repair site was significantly higher than the control repair site (93.96 [27.72] vs 42.62 [17.48] N/mm P<.001; 65.94 [24.51] vs 42.62 [17.48] N/mm P=.02, respectively). The tendon-fibrocartilage-bone composite bridging patch achieved higher ultimate tensile load and stiffness at the patch-greater tuberosity repair site compared with traditional repair in a canine model. This composite tissue transforms the traditional tendon-to-bone healing interface (with dissimilar tissues) into a pair of bone-to-bone and tendon-to-tendon interfaces, which may improve healing quality and reduce retear rate. Copyright © 2015 Elsevier Ltd. All rights reserved.

Post-tensioning tendon force loss detection using low power pulsed eddy current measurement

NASA Astrophysics Data System (ADS)

Kim, Ji-Min; Lee, Jun; Sohn, Hoon

2018-04-01

In the field of bridge engineering, pre-fabrication of a bridge member and its construction in site have been issued and studied, which achieves improved quality and rapid construction. For integration of those pre-fabricated segments into a structural member (i.e., a concrete slab, girder and pier), post-tensioning (PT) technique is adopted utilizing a high-strength steel tendon, and an effective investigation of the remaining PT tendon force is essential to assure an overall structural integrity. This study proposes a pulsed eddy current based tendon force loss detection system. A compact eddy current sensor is designed to be installed on the surface of an anchor holding a steel PT tendon. The intensity of the induced eddy current varies with PT tendon force alteration due to the magnetostriction effect of a ferromagnetic material. The advantages of the proposed system are as follows: (1) low power consumption, (2) rapid inspection, and (3) simple installation. Its performance was validated experimentally in a full-scale lab test of a 3.3-m long, 15.2-mm diameter mono-tendon that was tensioned using a universal testing machine. Tendon force was controlled from 20 to 180 kN with 20 kN interval, and eddy current responses were measured and analyzed at each force condition. The proposed damage index and the amount of force loss of PT tendon were monotonically related, and an excessive loss as much as 30 % of an initially-introduced tendon force was successfully predicted.

Hand Surgeon Reporting of Tendon Rupture Following Distal Radius Volar Plating

PubMed Central

Monaco, Nathan A.; Dwyer, C. Liam; Ferikes, Alex J.; Lubahn, John D.

2016-01-01

Background: Volar plate fixation with locked screws has become the preferred treatment of displaced distal radius fractures that cannot be managed nonoperatively. This treatment, however, is not without complication. The purpose of this study was to determine what percentage of hand surgeons, over a 12-month period, have experienced a tendon complication when using volar plates for the treatment of distal radius fractures. Methods: A total of 3022 hand surgeons were e-mailed a link to an online questionnaire regarding their observation and treatment of tendon injuries associated with volar plating of distal radius fractures. Responses were reported using descriptive statistics. Results: Of the 596 (20%) respondents, 199 (33%) surgeons reported encountering at least one flexor tendon injury after distal radius volar plating over the past year of practice. The flexor pollicis longus was the most commonly reported tendon injury (254, 75%). Palmaris longus grafting (118, 37%) and tendon transfer (114, 36%) were the most often reported treatments following this complication. A total of 216 respondents (36%) also encountered 324 cases of extensor tendon rupture after volar plating of distal radius fractures, with tendon transfer (88%) being the preferred treatment option. Conclusions: Both flexor and extensor tendon ruptures can be seen after volar plating of distal radius fractures. Surgeons should be aware of these complications. Critical assessment of hardware position at the time of index procedure is recommended to avoid complications. Long-term studies are needed to standardize approaches to managing tendon rupture following volar plating of distal radius fractures. PMID:27698628

Hand Surgeon Reporting of Tendon Rupture Following Distal Radius Volar Plating.

PubMed

Monaco, Nathan A; Dwyer, C Liam; Ferikes, Alex J; Lubahn, John D

2016-09-01

Background: Volar plate fixation with locked screws has become the preferred treatment of displaced distal radius fractures that cannot be managed nonoperatively. This treatment, however, is not without complication. The purpose of this study was to determine what percentage of hand surgeons, over a 12-month period, have experienced a tendon complication when using volar plates for the treatment of distal radius fractures. Methods: A total of 3022 hand surgeons were e-mailed a link to an online questionnaire regarding their observation and treatment of tendon injuries associated with volar plating of distal radius fractures. Responses were reported using descriptive statistics. Results: Of the 596 (20%) respondents, 199 (33%) surgeons reported encountering at least one flexor tendon injury after distal radius volar plating over the past year of practice. The flexor pollicis longus was the most commonly reported tendon injury (254, 75%). Palmaris longus grafting (118, 37%) and tendon transfer (114, 36%) were the most often reported treatments following this complication. A total of 216 respondents (36%) also encountered 324 cases of extensor tendon rupture after volar plating of distal radius fractures, with tendon transfer (88%) being the preferred treatment option. Conclusions: Both flexor and extensor tendon ruptures can be seen after volar plating of distal radius fractures. Surgeons should be aware of these complications. Critical assessment of hardware position at the time of index procedure is recommended to avoid complications. Long-term studies are needed to standardize approaches to managing tendon rupture following volar plating of distal radius fractures.

Observation of tendon repair in animal model using second-harmonic-generation microscopy

NASA Astrophysics Data System (ADS)

Hase, Eiji; Minamikawa, Takeo; Sato, Katsuya; Takahashi, Mitsuhiko; Yasui, Takashi

2016-03-01

Tendon rupture is a trauma difficult to recover the condition before injury. In previous researches, tensile test and staining method have been widely used to elucidate the mechanism of the repair process from the viewpoints of the mechanical property and the histological findings. However, since both methods are destructive and invasive, it is difficult to obtain both of them for the same sample. If both the mechanical property and the histological findings can be obtained from the same sample, one may obtain new findings regarding mechanisms of tendon repairing process. In this paper, we used second-harmonic-generation (SHG) microscopy, showing high selectivity and good image contrast to collagen molecules as well as high spatial resolution, optical three-dimensional sectioning, deep penetration, and without additional staining. Since SHG light intensity sensitively reflects the structural maturity of collagen molecule and its aggregates, it will be a good indicator for the repairing degree of the ruptured tendon. From comparison of SHG images between the 4-weeks-repaired tendon and the sound tendon in the animal model, we confirmed that SHG light intensity of the repaired tendon was significantly lower than that of the sound tendon, indicating that the collagen structure in the repaired tendon is still immature. Furthermore, we performed both SHG imaging and the tensile test for the same sample, and confirmed a correlation between them. This result shows a potential of SHG light for an indicator of the histological and mechanical recovery of the ruptured tendon.

Structural and biomechanical characteristics after early mobilization in an Achilles tendon rupture model: operative versus nonoperative treatment.

PubMed

Krapf, Daniel; Kaipel, Martin; Majewski, Martin

2012-09-01

Acute Achilles tendon ruptures are common sports injuries; however, treatment remains a clinical challenge. Studies show a superior effect of early mobilization and full weight bearing on tendon healing and clinical outcome; however, few data exist on structural and biomechanical characteristics in the early healing phase. This study investigated the histological and biomechanical characteristics of early mobilization and full weight bearing in an Achilles tendon rupture model. Eighty rats underwent dissection of a hindpaw Achilles tendon; 40 rats were treated conservatively and 40 underwent open repair of the transected Achilles tendon by suturing. Early mobilization and full weight bearing were allowed in both groups. At 1, 2, 4, and 8 weeks after tenotomy, tensile strength, stiffness, thickness, tissue characteristics (histological analysis), and length were determined. Dissected Achilles tendons healed in all animals during full weight-bearing early mobilization. One and 2 weeks after tenotomy, rats in the operative group showed increased tensile strength and stiffness compared with the nonoperative group. Repair-site diameters were increased at 1, 2, and 8 weeks after tenotomy. Tendon length was decreased in the operative group throughout observation, whereas the nonoperative group showed increased structural characteristics on the cellular level and a more homogeneous collagen distribution. Surgical treatment of dissected rat Achilles tendons showed superior biomechanical characteristics within the first 2 weeks. Conservative treatment resulted in superior histological findings but significant lengthening of the tendon in the early healing phase (weeks 1-8). Copyright 2012, SLACK Incorporated.

Prospective multicentre study of the clinical and functional outcomes following quadriceps tendon repair with suture anchors.

PubMed

Mille, F; Adam, A; Aubry, S; Leclerc, G; Ghislandi, X; Sergent, P; Garbuio, P

2016-01-01

Quadriceps tendon avulsions are typically treated by reattaching the tendon through bone tunnels, with or without tendon or hardware augmentation. The operated knee joint can be moved right away; however, tendon grafting or tension banding will be required to protect the repair, and the hardware must be removed later on. The goal of this study was to evaluate the clinical and functional outcomes when suture anchors are used to reattached torn quadriceps tendon, and also to assess tendon healing using MRI. Thirteen consecutive patients with avulsed quadriceps tendons were operated and then followed prospectively. The surgical technique consisted of tendon reattachment using at least three anchors, in addition to intratendinous weaving of the sutures. Weight bearing was allowed while using a splint. Rehabilitation was initiated immediately after surgery according to a set protocol. Eleven patients were followed for a mean of 14.7 months. Two retears occurred in patients who did not wear the splint. Eighty-two per cent of patients were satisfied or very satisfied with the outcome. The mean knee flexion was 124.5°. All patients were able to return to their pre-injury activity levels. The mean time for clinical and functional recovery was 3 months. MRI performed 6 months after the surgical repair revealed good tendon healing. This was the first prospective study performed on quadriceps avulsion patients undergoing suture anchor repair. Prior clinical case reports have shown that this method leads to predictable clinical and functional results. Our results were comparable to those in published cases. The procedure is simpler when only suture anchors are used. Tendon healing was observed on MRI in all cases. This simple, reproducible technique is free of the drawbacks associated with the typical repair augmentation.

Supraspinatus tendon micromorphology in individuals with subacromial pain syndrome.

PubMed

Pozzi, Federico; Seitz, Amee L; Plummer, Hillary A; Chow, Kira; Bashford, Gregory R; Michener, Lori A

Cross-sectional cohort. Tendon collagen organization can be estimated by peak spatial frequency radius (PSFR) on ultrasound images. Characterizing PSFR can define the contribution of collagen disruption to shoulder symptoms. The purpose of this was to characterize the (1) supraspinatus tendon PSFR in participants with subacromial pain syndrome (SPS) and healthy controls; (2) PSFR between participants grouped on a tendon visual quality score; and (3) relationship between PSFR with patient-reported pain, function, and shoulder strength. Participants with SPS (n = 20) and age, sex, and arm-dominance-matched healthy controls (n = 20) completed strength testing in scaption and external rotation, and patient-reported pain, and functional outcomes. Supraspinatus tendon ultrasound images were acquired, and PSFR was calculated for a region of interest 15 mm medial to the supraspinatus footprint. PSFR was compared between groups using an independent t-test and an analysis of variance to compare between 3 groups for visually qualitatively rated tendon abnormalities. Relationships between PSFR with pain, function, and strength were assessed using Pearson correlation coefficient. Supraspinatus tendon PSFR was not different between groups (P = .190) or tendon qualitative ratings (P = .556). No relationship was found between PSFR and pain, functional loss, and strength (P > .05). Collagen disruption (PSFR) measured via ultrasound images of the supraspinatus tendon was not different between participants with SPS or in those with visually rated tendon defects. PSFR is not related to shoulder pain, function, and strength, suggesting that supraspinatus tendon collagen disorganization may not be a contributing factor to shoulder SPS. However, collagen disruption may not be isolated to a single region of interest. 3b: case-control study. Copyright © 2017 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.

The role of bone sialoprotein in the tendon-bone insertion.

PubMed

Marinovich, Ryan; Soenjaya, Yohannes; Wallace, Gregory Q; Zuskov, Andre; Dunkman, Andrew; Foster, Brian L; Ao, Min; Bartman, Kevin; Lam, Vida; Rizkalla, Amin; Beier, Frank; Somerman, Martha J; Holdsworth, David W; Soslowsky, Louis J; Lagugné-Labarthet, François; Goldberg, Harvey A

2016-01-01

Tendons/ligaments insert into bone via a transitional structure, the enthesis, which is susceptible to injury and difficult to repair. Fibrocartilaginous entheses contain fibrocartilage in their transitional zone, part of which is mineralized. Mineral-associated proteins within this zone have not been adequately characterized. Members of the Small Integrin Binding Ligand N-linked Glycoprotein (SIBLING) family are acidic phosphoproteins expressed in mineralized tissues. Here we show that two SIBLING proteins, bone sialoprotein (BSP) and osteopontin (OPN), are present in the mouse enthesis. Histological analyses indicate that the calcified zone of the quadriceps tendon enthesis is longer in Bsp(-/-) mice, however no difference is apparent in the supraspinatus tendon enthesis. In an analysis of mineral content within the calcified zone, micro-CT and Raman spectroscopy reveal that the mineral content in the calcified fibrocartilage of the quadriceps tendon enthesis are similar between wild type and Bsp(-/-) mice. Mechanical testing of the patellar tendon shows that while the tendons fail under similar loads, the Bsp(-/-) patellar tendon is 7.5% larger in cross sectional area than wild type tendons, resulting in a 16.5% reduction in failure stress. However, Picrosirius Red staining shows no difference in collagen organization. Data collected here indicate that BSP is present in the calcified fibrocartilage of murine entheses and suggest that BSP plays a regulatory role in this structure, influencing the growth of the calcified fibrocartilage in addition to the weakening of the tendon mechanical properties. Based on the phenotype of the Bsp(-/-) mouse enthesis, and the known in vitro functional properties of the protein, BSP may be a useful therapeutic molecule in the reattachment of tendons and ligaments to bone. Copyright © 2016 International Society of Matrix Biology. All rights reserved.

Cell phenotypic variation in normal and damaged tendons

PubMed Central

Clegg, Peter D; Strassburg, Sandra; Smith, Roger K

2007-01-01

Injuries to tendons are common in both human athletes as well as in animals, such as the horse, which are used for competitive purposes. Furthermore, such injuries are also increasing in prevalence in the ageing, sedentary population. Tendon diseases often respond poorly to treatment and require lengthy periods of rehabilitation. The tendon has a unique extracellular matrix, which has developed to withstand the mechanical demands of such tensile-load bearing structures. Following injury, any repair process is inadequate and results in tissue that is distinct from original tendon tissue. There is growing evidence for the key role of the tendon cell (tenocyte) in both the normal physiological homeostasis and regulation of the tendon matrix and the pathological derangements that occur in disease. In particular, the tenocyte is considered to have a major role in effecting the subclinical matrix degeneration that is thought to occur prior to clinical disease, as well as in the severe degradative events that occur in the tendon at the onset of clinical disease. Furthermore, the tenocyte is likely to have a central role in the production of the biologically inadequate fibrocartilaginous repair tissue that develops subsequent to tendinopathy. Understanding the biology of the tenocyte is central to the development of appropriate interventions and drug therapies that will either prevent the onset of disease, or lead to more rapid and appropriate repair of injured tendon. Central to this is a full understanding of the proteolytic response in the tendon in disease by such enzymes as metalloproteinases, as well as the control of the inappropriate fibrocartilaginous differentiation. Finally, it is important that we understand the role of both intrinsic and extrinsic cellular elements in the repair process in the tendon subsequent to injury. PMID:17696903

The study of optical properties and proteoglycan content of tendons by PS-OCT

NASA Astrophysics Data System (ADS)

Yang, Ying; Rupani, Asha; Weightman, Alan; Wimpenny, Ian; Bagnaninchi, Pierre; Ahearne, Mark

2011-03-01

Tendons are load-bearing collagenous tissues consisting mainly of type I collagen and various proteoglycans (PGs) including decorin and versican. It is widely accepted that highly orientated collagen fibers in tendons a play critical role for transferring tensile stress and demonstrate birefringent optical properties. However, the influence that proteoglycans have on the optical properties of tendons is yet to be fully elucidated. Tendinopathy (defined as a syndrome of tendon pain, tenderness and swelling that affects the normal function of the tissue) is a common disease associated with sporting injuries or degeneration. PG's are the essential components of the tendon extracellular matrix; changes in their quantities and compositions have been associated with tendinopathy. In this study, polarization sensitive optical coherence tomography (PS-OCT) has been used to reveal the relationship between proteoglycan content/location and birefringent properties of tendons. Tendons dissected from freshly slaughtered chickens were imaged at regular intervals by PS-OCT and polarizing light microscope during the extraction of PGs or glycosaminoglycans using established protocols (guanidine hydrochloride (GuHCl) or proteinase K solution). The macroscopic and microscopic time lapsed images are complimentary; mutually demonstrating that there was a higher concentration of PG's in the outer sheath region than in the fascicles; and the integrity of the sheath affected extraction process and the OCT birefringence bands. Extraction of PGs using GuHCl disturbed the organization of local collagen bundles, which corresponded to a reduction in the frequency of birefringence bands and the band width by PS-OCT. The feature of OCT penetration depth helped us to define the heterogeneous distribution of PG's in tendon, which was complimented by polarizing light microscopy. The results provide new insight of tendon structure and also demonstrate a great potential for using PS-OCT as a diagnostic tool to examine tendon pathology.

The interfascicular matrix enables fascicle sliding and recovery in tendon, and behaves more elastically in energy storing tendons.

PubMed

Thorpe, Chavaunne T; Godinho, Marta S C; Riley, Graham P; Birch, Helen L; Clegg, Peter D; Screen, Hazel R C

2015-12-01

While the predominant function of all tendons is to transfer force from muscle to bone and position the limbs, some tendons additionally function as energy stores, reducing the cost of locomotion. Energy storing tendons experience extremely high strains and need to be able to recoil efficiently for maximum energy storage and return. In the equine forelimb, the energy storing superficial digital flexor tendon (SDFT) has much higher failure strains than the positional common digital extensor tendon (CDET). However, we have previously shown that this is not due to differences in the properties of the SDFT and CDET fascicles (the largest tendon subunits). Instead, there is a greater capacity for interfascicular sliding in the SDFT which facilitates the greater extensions in this particular tendon (Thorpe et al., 2012). In the current study, we exposed fascicles and interfascicular matrix (IFM) from the SDFT and CDET to cyclic loading followed by a test to failure. The results show that IFM mechanical behaviour is not a result of irreversible deformation, but the IFM is able to withstand cyclic loading, and is more elastic in the SDFT than in the CDET. We also assessed the effect of ageing on IFM properties, demonstrating that the IFM is less able to resist repetitive loading as it ages, becoming stiffer with increasing age in the SDFT. These results provide further indications that the IFM is important for efficient function in energy storing tendons, and age-related alterations to the IFM may compromise function and predispose older tendons to injury. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Does partial tear repair of adjacent tendons improve the outcome of supraspinatus tendonfull-thickness tear reinsertion?

PubMed

Nich, C; Dhiaf, N; Di Schino, M; Augereau, B

2014-11-01

Partial tearing of the infraspinatus and/or subscapularis tendon(s) is frequently associated with supraspinatus full-thickness tears. However, limited data regarding its influence on supraspinatus surgical repair is available. Our aim was to assess the functional and anatomical outcomes of open repair of supraspinatus full-thickness tears combined with adjacent partial tearing, comparatively to a control. We retrospectively identified 22 patients (22 shoulders) with a partial tear, most of them being a delamination tear, of the infraspinatus and/or subscapularis tendons associated with a complete detachment of the supraspinatus tendon. Twenty-seven patients (27 shoulders) treated for an isolated complete detachment of the supraspinatus tendon by open repair served as controls. The mean age was 58 years. A proximalized trans-osseous reinsertion of the supraspinatus tendon was combined with a curettage-closure of the delamination tear. Patients were evaluated with standardized MRI at last follow-up. At a mean of 75-month follow-up, the presence of a partial tear of either infraspinatus or subscapularis, or both, did not influence function and healing rates of supraspinatus tendon repair. Conversely to the control, when a retear occurred, the functional score tended to worsen. Preoperatively, fatty muscular degeneration was more pronounced when a partial tear was present. Fatty degeneration worsened regardless of repair healing. Open reinsertion of a supraspinatus full-thickness tear associated with a thorough treatment of partial tear of adjacent tendons led to optimal functional and anatomical mid term outcomes. Our results suggest the presence of a partial tear of adjacent tendons could be associated with poorer function in case of supraspinatus tendon re-rupture. Level III case-control study. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Landing strategies of athletes with an asymptomatic patellar tendon abnormality.

PubMed

Edwards, Suzi; Steele, Julie R; McGhee, Deirdre E; Beattie, Sue; Purdam, Craig; Cook, Jill L

2010-11-01

Risk factors associated with a clinical presentation of patellar tendinopathy are patellar tendon ultrasonographic abnormality (PTA) and excessive loading. It remains unknown whether characteristics of an athlete's landing technique contribute to this excessive patellar tendon loading. This study investigated whether asymptomatic athletes with and without PTA had different landing strategies and hypothesized that asymptomatic athletes with a PTA would create higher patellar tendon loading and a different lower-limb landing strategy compared with athletes with normal patellar tendons. Seven athletes with no previous history or clinical signs of patellar tendon injury with a PTA were matched to athletes with normal patellar tendons (controls). Participants performed five successful trials of a stop-jump task, which involved a simultaneous two-foot horizontal and then vertical landing. During each trial, the participants' ground reaction forces and lower-limb electromyographic data were recorded, the three-dimensional kinematics measured, and the peak patellar tendon force calculated by dividing the net knee joint moment by the patellar tendon moment arm. Significant between-group differences in landing technique were mostly observed during the horizontal landing phase. Participants with a PTA created similar patellar tendon loading to the controls, but with altered sequencing, by landing with significantly greater knee flexion and extending their hips while the controls flexed their hips as they landed, reflecting a different muscle recruitment order compared with the PTA group. The crucial part in the development of PTA and, in turn, patellar tendinopathy may not be the magnitude of the patellar tendon load but rather the loading patterns. This research provides clinicians with important landing assessment criteria against which to identify athletes at risk of developing patellar tendinopathy.

Tendon neuroplastic training: changing the way we think about tendon rehabilitation: a narrative review

PubMed Central

Rio, Ebonie; Kidgell, Dawson; Moseley, G Lorimer; Docking, Sean; Purdam, Craig; Cook, Jill

2016-01-01

Tendinopathy can be resistant to treatment and often recurs, implying that current treatment approaches are suboptimal. Rehabilitation programmes that have been successful in terms of pain reduction and return to sport outcomes usually include strength training. Muscle activation can induce analgesia, improving self-efficacy associated with reducing one's own pain. Furthermore, strength training is beneficial for tendon matrix structure, muscle properties and limb biomechanics. However, current tendon rehabilitation may not adequately address the corticospinal control of the muscle, which may result in altered control of muscle recruitment and the consequent tendon load, and this may contribute to recalcitrance or symptom recurrence. Outcomes of interest include the effect of strength training on tendon pain, corticospinal excitability and short interval cortical inhibition. The aims of this concept paper are to: (1) review what is known about changes to the primary motor cortex and motor control in tendinopathy, (2) identify the parameters shown to induce neuroplasticity in strength training and (3) align these principles with tendon rehabilitation loading protocols to introduce a combination approach termed as tendon neuroplastic training. Strength training is a powerful modulator of the central nervous system. In particular, corticospinal inputs are essential for motor unit recruitment and activation; however, specific strength training parameters are important for neuroplasticity. Strength training that is externally paced and akin to a skilled movement task has been shown to not only reduce tendon pain, but modulate excitatory and inhibitory control of the muscle and therefore, potentially tendon load. An improved understanding of the methods that maximise the opportunity for neuroplasticity may be an important progression in how we prescribe exercise-based rehabilitation in tendinopathy for pain modulation and potentially restoration of the corticospinal control of the muscle-tendon complex. PMID:26407586

Synovial Mesenchymal Stem Cells Promote Meniscus Regeneration Augmented by an Autologous Achilles Tendon Graft in a Rat Partial Meniscus Defect Model

PubMed Central

Ozeki, Nobutake; Muneta, Takeshi; Matsuta, Seiya; Koga, Hideyuki; Nakagawa, Yusuke; Mizuno, Mitsuru; Tsuji, Kunikazu; Mabuchi, Yo; Akazawa, Chihiro; Kobayashi, Eiji; Saito, Tomoyuki; Sekiya, Ichiro

2015-01-01

Although meniscus defects and degeneration are strongly correlated with the later development of osteoarthritis, the promise of regenerative medicine strategies is to prevent and/or delay the disease's progression. Meniscal reconstruction has been shown in animal models with tendon grafting and transplantation of mesenchymal stem cells (MSCs); however, these procedures have not shown the same efficacy in clinical studies. Here, our aim was to investigate the ability of tendon grafts pretreated with exogenous synovial-derived MSCs to prevent cartilage degeneration in a rat partial meniscus defect model. We removed the anterior half of the medial meniscus and grafted autologous Achilles tendons with or without a 10-minute pretreatment of the tendon with synovial MSCs. The meniscus and surrounding cartilage were evaluated at 2, 4, and 8 weeks (n = 5). Tendon grafts increased meniscus size irrespective of synovial MSCs. Histological scores for regenerated menisci were better in the tendon + MSC group than in the other two groups at 4 and 8 weeks. Both macroscopic and histological scores for articular cartilage were significantly better in the tendon + MSC group at 8 weeks. Implanted synovial MSCs survived around the grafted tendon and native meniscus integration site by cell tracking assays with luciferase+, LacZ+, DiI+, and/or GFP+ synovial MSCs and/or GFP+ tendons. Flow cytometric analysis showed that transplanted synovial MSCs retained their MSC properties at 7 days and host synovial tissue also contained cells with MSC characteristics. Synovial MSCs promoted meniscus regeneration augmented by autologous Achilles tendon grafts and prevented cartilage degeneration in rats. Stem Cells 2015;33:1927–1938 PMID:25993981

Tendon Healing in Bone Tunnel after Human Anterior Cruciate Ligament Reconstruction: A Systematic Review of Histological Results.

PubMed

Lu, Hongbin; Chen, Can; Xie, Shanshan; Tang, Yifu; Qu, Jin

2018-05-21

Most studies concerning to tendon healing and incorporation into bone are mainly based on animal studies due to the invasive nature of the biopsy procedure. The evidence considering tendon graft healing to bone in humans is limited in several case series or case reports, and therefore, it is difficult to understand the healing process. A computerized search using relevant search terms was performed in the PubMed, EMBASE, Scopus, and Cochrane Library databases, as well as a manual search of reference lists. Searches were limited to studies that investigated tendon graft healing to bone by histologic examination after anterior cruciate ligament (ACL) reconstruction with hamstring. Ten studies were determined to be eligible for this systematic review. Thirty-seven cases were extracted from the included studies. Most studies showed that a fibrovascular interface would form at the tendon-bone interface at the early stage and a fibrous indirect interface with Sharpey-like fibers would be expected at the later stage. Cartilage-like tissue at tendon graft-bone interface was reported in three studies. Tendon graft failed to integrate with the surrounding bone in 10 of the 37 cases. Unexpectedly, suspensory type of fixation was used for the above failure cases. An indirect type of insertion with Sharpey-like fibers at tendon-bone interface could be expected after ACL reconstruction with hamstring. Regional cartilage-like tissue may form at tendon-bone interface occasionally. The underlying tendon-to-bone healing process is far from understood in the human hamstring ACL reconstruction. Further human studies are highly needed to understand tendon graft healing in bone tunnel after hamstring ACL reconstruction. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

The Role of Bone Sialoprotein in the Tendon-Bone Insertion

PubMed Central

Marinovich, Ryan; Soenjaya, Yohannes; Wallace, Gregory Q.; Zuskov, Andre; Dunkman, Andrew; Foster, Brian L.; Ao, Min; Bartman, Kevin; Lam, Vida; Rizkalla, Amin; Beier, Frank; Somerman, Martha J.; Holdsworth, David W.; Soslowsky, Louis J.; Lagugné-Labarthet, François; Goldberg, Harvey A.

2016-01-01

Tendons/ligaments insert into bone via a transitional structure, the enthesis, which is susceptible to injury and difficult to repair. Fibrocartilaginous entheses contain fibrocartilage in their transitional zone, part of which is mineralized. Mineral-associated proteins within this zone have not been adequately characterized. Members of the Small Integrin Binding Ligand N-Linked Glycoprotein (SIBLING) family are acidic phosphoproteins expressed in mineralized tissues. Here we show that two SIBLING proteins, bone sialoprotein (BSP) and osteopontin (OPN), are present in the mouse enthesis. Histological analyses indicate that the calcified zone of the quadriceps tendon enthesis is longer in Bsp−/− mice, however no difference is apparent in the supraspinatus tendon enthesis. In an analysis of mineral content within the calcified zone, micro-CT and Raman spectroscopy reveal that the mineral content in the calcified fibrocartilage of the quadriceps tendon enthesis are similar between wild type and Bsp−/− mice. Mechanical testing of the patellar tendon shows that while the tendons fail under similar loads, the Bsp−/− patellar tendon is 7.5% larger in cross sectional area than wild type tendons, resulting in a 16.5% reduction in failure stress. However, picrosirius red staining shows no difference in collagen organization. Data collected here indicate that BSP is present in the calcified fibrocartilage of murine entheses and suggest that BSP plays a regulatory role in this structure, influencing the growth of the calcified fibrocartilage in addition to the weakening of the tendon mechanical properties. Based on the phenotype of the Bsp−/− mouse enthesis, and the known in vitro functional properties of the protein, BSP may be a useful therapeutic molecule in the reattachment of tendons and ligaments to bone. PMID:26826499

The effect of preheated tendon as a lean meat replacement on the properties of fine emulsion sausages.

PubMed

Sadler, D H; Young, O A

1993-01-01

Tendon from beef hind leg muscles was used to replace some of the lean in a conventional emulsion formulation. The tendon was homogenized and either used raw or preheated for 2·5 h at a range of temperatures (50, 60, 70, 80°C) before use. Texture analysis and sensory evaluation were performed on cylinders of cooked sausage. Texture analysis was carried out on formulations which had 20% of meat protein replaced by 20% tendons which were raw or had been preheated to 50, 60, 70, or 80°C. Fracturability decreased by about 40% with raw tendon, but was restored to within 20% of the no-replacement control if the tendon had been preheated. Hardness was approximately doubled by replacement with raw tendon or tendon heated at 50°C. At temperatures higher than that, hardness returned to approximately no-replacement levels. For sensory evaluation (0-25% replacement; preheating at 70°C), sausages were assessed by a 12-member panel for texture, flavour and overall acceptability. All attributes decreased with increasing collagen content, the decrease being less marked with preheated tendon. Thus more connective tissue could be added for the same panel score if the tissue was preheated. Comparison of the texture profile and the panel scores for texture at the same lean replacement level suggested that reduced fracturability was the texture parameter that panellists objected to when heated tendon replaced some of the lean. Other researchers have shown that connective tissue preheated to 100°C before addition in emulsion sausages results in improved yields and better sensory attributes, but the present results show that temperatures as low as 60°C can be effective for beef tendon. Copyright © 1993. Published by Elsevier Ltd.

Extracorporeal shock waves promote healing of collagenase-induced Achilles tendinitis and increase TGF-beta1 and IGF-I expression.

PubMed

Chen, Yeung-Jen; Wang, Ching-Jen; Yang, Kuender D; Kuo, Yur-Ren; Huang, Hui-Chen; Huang, Yu-Ting; Sun, Yi-Chih; Wang, Feng-Sheng

2004-07-01

Extracorporeal shock waves (ESW) have recently been used in resolving tendinitis. However, mechanisms by which ESW promote tendon repair is not fully understood. In this study, we reported that an optimal ESW treatment promoted healing of Achilles tendintis by inducing TGF-beta1 and IGF-I. Rats with the collagenease-induced Achilles tendinitis were given a single ESW treatment (0.16 mJ/mm(2) energy flux density) with 0, 200, 500 and 1000 impulses. Achilles tendons were subjected to biomechanical (load to failure and stiffness), biochemical properties (DNA, glycosaminoglycan and hydroxyproline content) and histological assessment. ESW with 200 impulses restored biomechanical and biochemical characteristics of healing tendons 12 weeks after treatment. However, ESW treatments with 500 and 1000 impulses elicited inhibitory effects on tendinitis repair. Histological observation demonstrated that ESW treatment resolved edema, swelling, and inflammatory cell infiltration in injured tendons. Lesion site underwent intensive tenocyte proliferation, neovascularization and progressive tendon tissue regeneration. Tenocytes at the hypertrophied cellular tissue and newly developed tendon tissue expressed strong proliferating cell nuclear antigen (PCNA) after ESW treatment, suggesting that physical ESW could increase the mitogenic responses of tendons. Moreover, the proliferation of tenocytes adjunct to hypertrophied cell aggregate and newly formed tendon tissue coincided with intensive TGF-beta1 and IGF-I expression. Increasing TGF-beta1 expression was noted in the early stage of tendon repair, and elevated IGF-I expression was persisted throughout the healing period. Together, low-energy shock wave effectively promoted tendon healing. TGF-beta1 and IGF-I played important roles in mediating ESW-stimulated cell proliferation and tissue regeneration of tendon.

Beneficial Effects of Autologous Bone Marrow-Derived Mesenchymal Stem Cells in Naturally Occurring Tendinopathy

PubMed Central

Smith, Roger Kenneth Whealands; Werling, Natalie Jayne; Dakin, Stephanie Georgina; Alam, Rafiqul; Goodship, Allen E.; Dudhia, Jayesh

2013-01-01

Tendon injuries are a common age-related degenerative condition where current treatment strategies fail to restore functionality and normal quality of life. This disease also occurs naturally in horses, with many similarities to human tendinopathy making it an ideal large animal model for human disease. Regenerative approaches are increasingly used to improve outcome involving mesenchymal stem cells (MSCs), supported by clinical data where injection of autologous bone marrow derived MSCs (BM-MSCs) suspended in marrow supernatant into injured tendons has halved the re-injury rate in racehorses. We hypothesized that stem cell therapy induces a matrix more closely resembling normal tendon than the fibrous scar tissue formed by natural repair. Twelve horses with career-ending naturally-occurring superficial digital flexor tendon injury were allocated randomly to treatment and control groups. 1X107 autologous BM-MSCs suspended in 2 ml of marrow supernatant were implanted into the damaged tendon of the treated group. The control group received the same volume of saline. Following a 6 month exercise programme horses were euthanized and tendons assessed for structural stiffness by non-destructive mechanical testing and for morphological and molecular composition. BM-MSC treated tendons exhibited statistically significant improvements in key parameters compared to saline-injected control tendons towards that of normal tendons and those in the contralateral limbs. Specifically, treated tendons had lower structural stiffness (p<0.05) although no significant difference in calculated modulus of elasticity, lower (improved) histological scoring of organisation (p<0.003) and crimp pattern (p<0.05), lower cellularity (p<0.007), DNA content (p<0.05), vascularity (p<0.03), water content (p<0.05), GAG content (p<0.05), and MMP-13 activity (p<0.02). Treatment with autologous MSCs in marrow supernatant therefore provides significant benefits compared to untreated tendon repair in enhancing normalisation of biomechanical, morphological, and compositional parameters. These data in natural disease, with no adverse findings, support the use of this treatment for human tendon injuries. PMID:24086616

The effects of platelet lysate patches on the activity of tendon-derived cells.

PubMed

Costa-Almeida, Raquel; Franco, Albina R; Pesqueira, Tamagno; Oliveira, Mariana B; Babo, Pedro S; Leonor, Isabel B; Mano, João F; Reis, Rui L; Gomes, Manuela E

2018-03-01

Platelet-derived biomaterials are widely explored as cost-effective sources of therapeutic factors, holding a strong potential for endogenous regenerative medicine. Particularly for tendon repair, treatment approaches that shift the injury environment are explored to accelerate tendon regeneration. Herein, genipin-crosslinked platelet lysate (PL) patches are proposed for the delivery of human-derived therapeutic factors in patch augmentation strategies aiming at tendon repair. Developed PL patches exhibited a controlled release profile of PL proteins, including bFGF and PDGF-BB. Additionally, PL patches exhibited an antibacterial effect by preventing the adhesion, proliferation and biofilm formation by S. aureus, a common pathogen in orthopaedic surgical site infections. Furthermore, these patches supported the activity of human tendon-derived cells (hTDCs). Cells were able to proliferate over time and an up-regulation of tenogenic genes (SCX, COL1A1 and TNC) was observed, suggesting that PL patches may modify the behavior of hTDCs. Accordingly, hTDCs deposited tendon-related extracellular matrix proteins, namely collagen type I and tenascin C. In summary, PL patches can act as a reservoir of biomolecules derived from PL and support the activity of native tendon cells, being proposed as bioinstructive patches for tendon regeneration. Platelet-derived biomaterials hold great interest for the delivery of therapeutic factors for applications in endogenous regenerative medicine. In the particular case of tendon repair, patch augmentation strategies aiming at shifting the injury environment are explored to improve tendon regeneration. In this study, PL patches were developed with remarkable features, including the controlled release of growth factors and antibacterial efficacy. Remarkably, PL patches supported the activity of native tendon cells by up-regulating tenogenic genes and enabling the deposition of ECM proteins. This patch holds great potential towards simultaneously reducing post-implantation surgical site infections and promoting tendon regeneration for prospective in vivo applications. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

[Reconstruction of the extensor pollicis longus tendon by transposition of the extensor indicis tendon].

PubMed

Loos, A; Kalb, K; Van Schoonhoven, J; Landsleitner Dagger, B

2003-12-01

Rupture of the extensor pollicis longus-tendon (EPL) is a frequent complication after distal radius fractures. Other traumatic and non-traumatic reasons for this tendon lesion are known, including a theory about a disorder in the blood supply to the tendon itself. We examined 40 patients after reconstruction of the EPL-tendon in a mean follow-up time of 30 months. All patients were clinically examined and a DASH questionnaire was answered by all patients. The method to reconstruct the EPL-tendon was the transposition of the extensor indicis-tendon. After the operations the thumb was put in a splint for four weeks in a "hitch-hiker's-position". 31 ruptures of the tendon (77.5 %) were a result of trauma. In 20 of them (50 %) a distal radius fracture had occurred. Clinical examination included measurements of the movement of the thumb- and index-finger joints, the grip strength and the maximal span of the hand. Significant differences were not found. The isolated extension of the index finger was possible in all patients. But it was reduced in ten cases which represent 25 %. Our results were evaluated by the Geldmacher score to evaluate the reconstruction of the EPL-tendon. 20 % excellent, 65 % good, 12.5 % fair and 2.5 % poor results were reached. The Geldmacher score was used critically. We suggest its modification for the evaluation of thumb abduction. The DASH score reached a functional value of ten points which represents a very good result. In conclusion the extensor indicis-transposition is a safe method to reconstruct the EPL-tendon. Its substantial advantage is taking a healthy muscle as the motor, thereby avoiding the risk of using a degenerated muscle in late tendon reconstruction. A powerful extension of the index finger will be maintained by physical education. Generally, the loss of the extension of the index finger is negligible. It does not disturb the patients. But it has to be discussed with the patient before the operation.

Biomechanical characteristics of the horizontal mattress stitch: implication for double-row and suture-bridge rotator cuff repair.

PubMed

Tamboli, Mallika; Mihata, Teruhisa; Hwang, James; McGarry, Michelle H; Kang, Yangmi; Lee, Thay Q

2014-03-01

We investigated the effects of bite-size horizontal mattress stitch (distance between the limbs passed through the tendon) on the biomechanical properties of the repaired tendon. We anchored 20 bovine Achilles tendons to bone using no. 2 high-strength suture and 5-mm titanium suture anchors in a mattress-suture technique. Tendons were allocated randomly into two groups of ten each to receive stitches with a 4- or 10-mm bite. Specimens underwent cyclic loading from 5 to 30 N at 1 mm/s for 30 cycles, followed by tensile testing to failure. Gap formation, tendon strain, hysteresis, stiffness, yield load, ultimate load, energy to yield load, and energy to ultimate load were compared between groups using unpaired t tests. The 4-mm group had less (p < 0.05) gap formation and less (p < 0.05) longitudinal strain than did the 10-mm group. Ultimate load (293.6 vs. 148.9 N) and energy to ultimate load (2,563 vs. 1,472 N-mm) were greater (p < 0.001) for the 10-mm group than the 4-mm group. All tendons repaired with 4-mm suturing failed at the suture-tendon interface, with sutures pulling through the tendon, whereas the suture itself failed before the tendon did in seven of the ten specimens in the 10-mm group. Whereas a 4-mm bite fixed the tendon more tightly but at the cost of decreased ultimate strength, a 10-mm bite conveyed greater ultimate strength but with increased gap and strain. These results suggest that for the conventional double-row repair, small mattress stitches provide a tighter repair, whereas large stitches are beneficial to prevent sutures from pulling through the tendon after surgery. For suture-bridge rotator cuff repair, large stitches are beneficial because the repaired tendon has a higher strength, and the slightly mobile medial knot can be tightened by lateral fixation.

A robust method for RNA extraction and purification from a single adult mouse tendon.

PubMed

Grinstein, Mor; Dingwall, Heather L; Shah, Rishita R; Capellini, Terence D; Galloway, Jenna L

2018-01-01

Mechanistic understanding of tendon molecular and cellular biology is crucial toward furthering our abilities to design new therapies for tendon and ligament injuries and disease. Recent transcriptomic and epigenomic studies in the field have harnessed the power of mouse genetics to reveal new insights into tendon biology. However, many mouse studies pool tendon tissues or use amplification methods to perform RNA analysis, which can significantly increase the experimental costs and limit the ability to detect changes in expression of low copy transcripts. Single Achilles tendons were harvested from uninjured, contralateral injured, and wild type mice between three and five months of age, and RNA was extracted. RNA Integrity Number (RIN) and concentration were determined, and RT-qPCR gene expression analysis was performed. After testing several RNA extraction approaches on single adult mouse Achilles tendons, we developed a protocol that was successful at obtaining high RIN and sufficient concentrations suitable for RNA analysis. We found that the RNA quality was sensitive to the time between tendon harvest and homogenization, and the RNA quality and concentration was dependent on the duration of homogenization. Using this method, we demonstrate that analysis of Scx gene expression in single mouse tendons reduces the biological variation caused by pooling tendons from multiple mice. We also show successful use of this approach to analyze Sox9 and Col1a2 gene expression changes in injured compared with uninjured control tendons. Our work presents a robust, cost-effective, and straightforward method to extract high quality RNA from a single adult mouse Achilles tendon at sufficient amounts for RT-qPCR as well as RNA-seq. We show this can reduce variation and decrease the overall costs associated with experiments. This approach can also be applied to other skeletal tissues, as well as precious human samples.

Inducement of tissue regeneration of harvested hamstring tendons in a rabbit model

PubMed Central

Soejima, T.; Murakami, H.; Noguchi, K.; Shiba, N.; Nagata, K.

2016-01-01

Objectives The objective of this study was to determine if the use of fascia lata as a tendon regeneration guide (placed into the tendon canal following harvesting the semitendinosus tendon) would improve the incidence of tissue regeneration and prevent fatty degeneration of the semitendinosus muscle. Materials and Methods Bilateral semitendinosus tendons were harvested from rabbits using a tendon stripper. On the inducing graft (IG) side, the tendon canal and semitendinosus tibial attachment site were connected by the fascia lata, which was harvested at the same width as the semitendinosus tendon. On the control side, no special procedures were performed. Two groups of six rabbits were killed at post-operative weeks 4 and 8, respectively. In addition, three healthy rabbits were killed to obtain normal tissue. We evaluated the incidence of tendon tissue regeneration, cross-sectional area of the regenerated tendon tissue and proportion of fatty tissue in the semitendinosus muscle. Results At post-operative week 8, the distal end of the regenerated tissue reached the vicinity of the tibial insertion on the control side in two of six specimens. On the IG side, the regenerated tissue maintained continuity with the tibial insertion in all specimens. The cross-sectional area of the IG side was significantly greater than that of the control side. The proportion of fatty tissue in the semitendinosus muscle on the IG side was comparable with that of the control side, but was significantly greater than that of the normal muscle. Conclusions Tendon tissue regenerated with the fascia lata graft was thicker than naturally occurring regenerated tissue. However, the proportion of fatty tissue in the semitendinosus muscle was greater than that of normal muscle. Cite this article: K. Tabuchi, T. Soejima, H. Murakami, K. Noguchi, N. Shiba, K. Nagata. Inducement of tissue regeneration of harvested hamstring tendons in a rabbit model. Bone Joint Res 2016;5:247–252. DOI: 10.1302/2046-3758.56.2000585. PMID:27340141

Extracorporeal shock wave therapy for calcific and noncalcific tendonitis of the rotator cuff: a systematic review.

PubMed

Harniman, Elaine; Carette, Simon; Kennedy, Carol; Beaton, Dorcas

2004-01-01

The authors conducted a systematic review to assess the effectiveness of extracorporeal shock wave therapy (ESWT) for the treatment of calcific and noncalcific tendonitis of the rotator cuff. Conservative treatment for rotator cuff tendonitis includes physiotherapy, nonsteroidal antiinflammatory drugs, and corticosteroid injections. If symptoms persist with conservative treatment, surgery is often considered. Extracorporeal shock wave therapy has been suggested as a treatment alternative for chronic rotator cuff tendonitis, which may decrease the need for surgery. Articles for this review were identified by electronically searching Medline, EMBASE, Cumulative Index to Nursing & Allied Health Literature (CINAHL), and Evidence Based Medicine (EBM) and hand-screening references. Two reviewers selected the trials that met the inclusion criteria, extracted the data, and assessed the methodological quality of the selected trials. Finally, the strength of scientific evidence was appraised. Evidence was classified as strong, moderate, limited, or conflicting. Sixteen trials met the inclusion criteria. There were only five randomized, controlled trials and all involved chronic (>/=3 months) conditions, three for calcific tendonitis and two for noncalcific tendonitis. For randomized, controlled trials, two (40%) were of high quality, one (33%) for calcific tendonitis and one (50%) for noncalcific tendonitis. The 11 nonrandomized trials included nine that involved calcific tendonitis and two that involved both calcific and noncalcific tendonitis. Common problem areas were sample size, randomization, blinding, treatment provider bias, and outcome measures. There is moderate evidence that high-energy ESWT is effective in treating chronic calcific rotator cuff tendonitis when the shock waves are focused at the calcified deposit. There is moderate evidence that low-energy ESWT is not effective for treating chronic noncalcific rotator cuff tendonitis, although this conclusion is based on only one high-quality study, which was underpowered. High-quality randomized, controlled trials are needed with larger sample sizes, better randomization and blinding, and better outcome measures.

The Incidence of Acute Traumatic Tendon Injuries in the Hand and Wrist: A 10-Year Population-based Study

PubMed Central

de Jong, Johanna P.; Nguyen, Jesse T.; Sonnema, Anne J. M.; Nguyen, Emily C.; Amadio, Peter C.

2014-01-01

Background Acute traumatic tendon injuries of the hand and wrist are commonly encountered in the emergency department. Despite the frequency, few studies have examined the true incidence of acute traumatic tendon injuries in the hand and wrist or compared the incidences of both extensor and flexor tendon injuries. Methods We performed a retrospective population-based cohort study of all acute traumatic tendon injuries of the hand and wrist in a mixed urban and rural Midwest county in the United States between 2001-2010. A regional epidemiologic database and medical codes were used to identify index cases. Epidemiologic information including occupation, year of injury, mechanism of injury and the injured tendon and zone were recorded. Results During the 10-year study period there was an incidence rate of 33.2 injuries per 100,000 person-years. There was a decreasing rate of injury during the study period. Highest incidence of injury occurred at 20-29 years of age. There was significant association between injury rate and age, and males had a higher incidence than females. The majority of cases involved a single tendon, with extensor tendon injuries occurring more frequently than flexor tendons. Typically, extensor tendon injuries involved zone three of the index finger, while flexor tendons involved zone two of the index finger. Work-related injuries accounted for 24.9% of acute traumatic tendon injuries. The occupations of work-related injuries were assigned to major groups defined by the 2010 Standard Occupational Classification structure. After assigning these patients' occupations to respective major groups, the most common groups work-related injuries occurred in construction and extraction occupations (44.2%), food preparation and serving related occupations (14.4%), and transportation and material moving occupations (12.5%). Conclusions Epidemiology data enhances our knowledge of injury patterns and may play a role in the prevention and treatment of future injuries, with an end result of reducing lost work time and economic burden. PMID:24900902

The biophysical characteristics of human composite flexor tendon allograft for upper extremity reconstruction.

PubMed

DeGeorge, Brent R; Rodeheaver, George T; Drake, David B

2014-01-01

Devastating volar hand injuries with significant damage to the skin and soft tissues, pulley structures and fibro-osseous sheath, flexor tendons, and volar plates pose a major problem to the reconstructive hand surgeon. Despite advances in tendon handling, operative technique, and postoperative hand rehabilitation, patients who have undergone flexor tendon reconstruction are often plagued by chronic pain, stiffness, and decreased range of motion with resultant decreased ability to work and poor quality of life. In this article, we expand the technique of human composite flexor tendon allografts (CFTAs), pioneered by Dr E.E. Peacock, Jr, which consist of both the intrasynovial and extrasynovial flexor digitorum superficialis and flexor digitorum profundus tendons and their respective fibro-osseous sheath consisting of the digital pulley structures, periosteum, and volar plates procured from cadaveric donors with the use of modern tissue processing techniques. Human cadaveric CFTAs were procured and divided into 2 groups-unprocessed CFTAs and processed CFTAs, which are cleansed and sterilized to a sterility assurance level of 10(-6). Physical length and width relationships as well as tensile strength and gliding resistance assessments were recorded pre-tissue and post-tissue processing. The histologic properties of the composite allografts were assessed before and after tissue processing. There was no significant difference with respect to physical properties of the composite allografts before or after tissue processing. The processed composite allografts demonstrated equivalent maximum load to failure and elastic modulus compared to unprocessed tendons. The gliding resistance of the composite tendon allografts was not significantly different between the 2 groups. The use of CFTAs addresses the issues of adhesion formation and lack of suitable donor material by providing a source of intrasynovial tendon in its unaltered fibro-osseous sheath without donor morbidity. This approach represents an important step toward designing an ideal material for complex flexor tendon reconstruction, which takes advantage of an intrasynovial flexor tendon in its native fibro-osseous sheath without the need for additional donor morbidity using a construct which can be engineered to have minimal tissue reactivity, negligible potential for disease transmission, and improved tendon healing properties versus standard tendon allograft.

Intramuscular tendon involvement on MRI has limited value for predicting time to return to play following acute hamstring injury.

PubMed

van der Made, Anne D; Almusa, Emad; Whiteley, Rod; Hamilton, Bruce; Eirale, Cristiano; van Hellemondt, Frank; Tol, Johannes L

2018-01-01

Hamstring injury with intramuscular tendon involvement is regarded as a serious injury with a delay in return to play (RTP) of more than 50 days and reinjury rates up to 63%. However, this reputation is based on retrospective case series with high risk of bias. Determine whether intramuscular tendon involvement is associated with delayed RTP and elevated rates of reinjury. MRI of male athletes with an acute hamstring injury was obtained within 5 days of injury. Evaluation included standardised MRI scoring and scoring of intramuscular tendon involvement. Time to RTP and reinjury rate were prospectively recorded. Out of 70 included participants, intramuscular tendon disruption was present in 29 (41.4%) injuries. Injuries without intramuscular tendon disruption had a mean time to RTP of 22.2±7.4 days. Injuries with <50%, 50%-99% and 100% disruption of tendon cross-sectional area had a mean time to RTP of 24.0±9.7, 25.3±8.6 and 31.6±10.9 days, respectively. Injuries with full-thickness disruption took longer to RTP compared with injuries without disruption (p=0.025). Longitudinal intramuscular tendon disruption was not significantly associated with time to RTP. Waviness was present in 17 (24.3%) injuries. Mean time to RTP for injuries without and with waviness was 22.6±7.5 and 30.2±10.8 days (p=0.014). There were 11 (15.7%) reinjuries within 12 months, five (17.2%) in the group with intramuscular tendon disruption and six (14.6%) in the group without intramuscular tendon disruption. Time to RTP for injuries with full-thickness disruption of the intramuscular tendon and waviness is significantly longer (by slightly more than 1 week) compared with injuries without intramuscular tendon involvement. However, due to the considerable overlap in time to RTP between groups with and without intramuscular tendon involvement, its clinical significance for the individual athlete is limited. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Triceps surae muscle-tendon properties in older endurance- and sprint-trained athletes.

PubMed

Stenroth, Lauri; Cronin, Neil J; Peltonen, Jussi; Korhonen, Marko T; Sipilä, Sarianna; Finni, Taija

2016-01-01

Previous studies have shown that aging is associated with alterations in muscle architecture and tendon properties (Morse CI, Thom JM, Birch KM, Narici MV. Acta Physiol Scand 183: 291-298, 2005; Narici MV, Maganaris CN, Reeves ND, Capodaglio P. J Appl Physiol 95: 2229-2234, 2003; Stenroth L, Peltonen J, Cronin NJ, Sipila S, Finni T. J Appl Physiol 113: 1537-1544, 2012). However, the possible influence of different types of regular exercise loading on muscle architecture and tendon properties in older adults is poorly understood. To address this, triceps surae muscle-tendon properties were examined in older male endurance (OE, n = 10, age = 74.0 ± 2.8 yr) and sprint runners (OS, n = 10, age = 74.4 ± 2.8 yr), with an average of 42 yr of regular training experience, and compared with age-matched [older control (OC), n = 33, age = 74.8 ± 3.6 yr] and young untrained controls (YC, n = 18, age = 23.7 ± 2.0 yr). Compared with YC, Achilles tendon cross-sectional area (CSA) was 22% (P = 0.022), 45% (P = 0.001), and 71% (P < 0.001) larger in OC, OE, and OS, respectively. Among older groups, OS had significantly larger tendon CSA compared with OC (P = 0.033). No significant between-group differences were observed in Achilles tendon stiffness. In older groups, Young's modulus was 31-44%, and maximal tendon stress 44-55% lower, than in YC (P ≤ 0.001). OE showed shorter soleus fascicle length than both OC (P < 0.05) and YC (P < 0.05). These data suggest that long-term running does not counteract the previously reported age-related increase in tendon CSA, but, instead, may have an additive effect. The greatest Achilles tendon CSA was observed in OS followed by OE and OC, suggesting that adaptation to running exercise is loading intensity dependent. Achilles tendon stiffness was maintained in older groups, even though all older groups displayed larger tendon CSA and lower tendon Young's modulus. Shorter soleus muscle fascicles in OE runners may be an adaptation to life-long endurance running. Copyright © 2016 the American Physiological Society.

Therapeutic Effects of Doxycycline on the Quality of Repaired and Unrepaired Achilles Tendons.

PubMed

Nguyen, Quynhhoa T; Norelli, Jolanta B; Graver, Adam; Ekstein, Charles; Schwartz, Johnathan; Chowdhury, Farzana; Drakos, Mark C; Grande, Daniel A; Chahine, Nadeen O

2017-10-01

Achilles tendon tears are devastating injuries, especially to athletes. Elevated matrix metalloproteinase (MMP) activity after a tendon injury has been associated with deterioration of the collagen network and can be inhibited with doxycycline (Doxy). Daily oral administration of Doxy will enhance the histological, molecular, and biomechanical quality of transected Achilles tendons. Additionally, suture repair will further enhance the quality of repaired tendons. Controlled laboratory study. Randomized unilateral Achilles tendon transection was performed in 288 adult male Sprague-Dawley rats. The injured tendons were either unrepaired (groups 1 and 2) or surgically repaired (groups 3 and 4). Animals from groups 2 and 4 received Doxy daily through oral gavage, and animals from groups 1 and 3 served as controls (no Doxy). Tendons were harvested at 1.5, 3, 6, and 9 weeks after the injury (n = 18 per group and time point). The quality of tendon repair was evaluated based on the histological grading score, collagen fiber orientation, gene expression, and biomechanical properties. In surgically repaired samples, Doxy enhanced the quality of tendon repair compared with no Doxy ( P = .0014). Doxy had a significant effect on collagen fiber dispersion, but not principal fiber angle. There was a significant effect of time on the gene expression of MMP-3, MMP-9 and TIMP1, and Doxy significantly decreased MMP-3 expression at 9 weeks. Doxy treatment with surgical repair increased the dynamic modulus at 6 weeks but not at 9 weeks after the injury ( P < .001). Doxy also increased the equilibrium modulus and decreased creep strain irrespective of the repair group. Doxy did not have a significant effect on the histology or biomechanics of unrepaired tendons. The findings indicate that daily oral administration of Doxy accelerated matrix remodeling and the dynamic and equilibrium biomechanics of surgically repaired Achilles tendons, although such enhancements were most evident at the 3- to 6-week time points. The inhibition of MMPs at the optimal stage of the repair process may accelerate Achilles tendon repair and improve biomechanical properties, especially when paired with surgical management.

The Effects of Mechanical Loading on Tendons - An In Vivo and In Vitro Model Study

PubMed Central

Zhang, Jianying; Wang, James H-C.

2013-01-01

Mechanical loading constantly acts on tendons, and a better understanding of its effects on the tendons is essential to gain more insights into tendon patho-physiology. This study aims to investigate tendon mechanobiological responses through the use of mouse treadmill running as an in vivo model and mechanical stretching of tendon cells as an in vitro model. In the in vivo study, mice underwent moderate treadmill running (MTR) and intensive treadmill running (ITR) regimens. Treadmill running elevated the expression of mechanical growth factors (MGF) and enhanced the proliferative potential of tendon stem cells (TSCs) in both patellar and Achilles tendons. In both tendons, MTR upregulated tenocyte-related genes: collagen type I (Coll. I ∼10 fold) and tenomodulin (∼3–4 fold), but did not affect non-tenocyte-related genes: LPL (adipocyte), Sox9 (chondrocyte), Runx2 and Osterix (both osteocyte). However, ITR upregulated both tenocyte (Coll. I ∼7–11 fold; tenomodulin ∼4–5 fold) and non-tenocyte-related genes (∼3–8 fold). In the in vitro study, TSCs and tenocytes were stretched to 4% and 8% using a custom made mechanical loading system. Low mechanical stretching (4%) of TSCs from both patellar and Achilles tendons increased the expression of only the tenocyte-related genes (Coll. I ∼5–6 fold; tenomodulin ∼6–13 fold), but high mechanical stretching (8%) increased the expression of both tenocyte (Coll. I ∼28–50 fold; tenomodulin ∼14–48 fold) and non-tenocyte-related genes (2–5-fold). However, in tenocytes, non-tenocyte related gene expression was not altered by the application of either low or high mechanical stretching. These findings indicate that appropriate mechanical loading could be beneficial to tendons because of their potential to induce anabolic changes in tendon cells. However, while excessive mechanical loading caused anabolic changes in tendons, it also induced differentiation of TSCs into non-tenocytes, which may lead to the development of degenerative tendinopathy frequently seen in clinical settings. PMID:23977130

Prophylactic training in asymptomatic soccer players with ultrasonographic abnormalities in Achilles and patellar tendons: the Danish Super League Study.

PubMed

Fredberg, Ulrich; Bolvig, Lars; Andersen, Niels T

2008-03-01

A recent study published in The American Journal of Sports Medicine showed that asymptomatic soccer players with an increased risk of developing Achilles and patellar tendon injuries within the next 12 months can be identified with use of ultrasonography. Prophylactic eccentric training and stretching can reduce both the frequency of asymptomatic ultrasonographic changes in Achilles and patellar tendons in soccer players and the risk of these asymptomatic intratendinous changes becoming symptomatic. Randomized controlled trial; Level of evidence, 1. Two hundred and nine Danish professional soccer players from the best national league (Super League) were followed over 12 months with use of ultrasonography and injury registration. Half the teams were randomized to an intervention group with prophylactic eccentric training and stretching of the Achilles and patellar tendons during the soccer season. The eccentric training and stretching did not reduce the injury risk, and, contrary to all expectations, the injury risk during the season was increased in players with abnormal patellar tendons at the beginning of the study in January. Eccentric training and stretching in players with normal patellar tendons significantly reduced the proportion of players with ultrasonographic changes in the patellar tendons at the end of the season (risk difference [RD] = 12%; 95% confidence interval [CI], 2%-22%; P = .02), but the training had no effect on the Achilles tendons (RD = 1%; 95% CI, -7% to 9%; P = .75). The presence of preseason ultrasonographic abnormalities in the tendons significantly increased the risk of developing tendon symptoms during the season (relative risk = 1.9; 95% CI, 1.2-3.1; P = .009). This study demonstrates that with the use of ultrasonography, tendon changes in soccer players can be diagnosed before they become symptomatic. The prophylactic eccentric training and stretching program reduces the risk of developing ultrasonographic abnormalities in the patellar tendons but has no positive effects on the risk of injury. On the contrary, in asymptomatic players with ultrasonographically abnormal patellar tendons, prophylactic eccentric training and stretching increased the injury risk.

[HEALING MODEL RESEARCH OF ROTATOR CUFF INJURY IN CANINE].

PubMed

Ye, Wei; Bao, Nirong; Zhaq, Jianning

2016-04-01

To compare the difference of rotator cuff healing between different types of injury andbetween different repair methods, and to explore the animal model to accurately simulate the restorative process afterrepair of rotator cuff injury. Twelve adult male beagle dogs (weighing, 10-15 kg) were divided into 3 groups (n = 4) according to different processing methods: acute rotator cuff injury+Mason-Allen suture repair (group A), huge rotator cuff injury+Mason-Allen suture repair (group B), and huge rotator cuff injury+Mason-Allen combined with autogenous semitendinosus expansion suture repair (group C). The external fixation was used for immobilization after repair. After operation, the general situation of the animals was observed, and the infraspinatus tendon was harvested for gross observation at 6 weeks after operation. The biomechanical test of limit load and histological observation of tendon fibers were carried out. All the animals survived to the end of the experiment. All incisions healed well and no infection occurred. Gross observation showed more scar tissues at the end of infraspinatus muscle tendon than normal tendon in group A; no obvious tendon tissue was observed at the end of infraspinatus muscle tendon in group B; the infraspinatus muscle tendon was covered with some white scar tissue, but the tendon and the general direction could be observed in group C. The limit load of groups A, B, and C were (223.75 ± 24.28), (159.25 ± 34.87), and (233.25 ± 14.24) N respectively, group B was significantly lower than groups A and C (P < 0.05), and no significant differnce was found between group A and group C (P > 0.05). Histological observation showed normal arrangement of tendon fibers in group A; tendon fibers arranged disorderly in group B and tendon cells were significantly less than those of group A; tendon fibers arranged in neat in group C and tendon cells were more than those of group B. Canine autologous semitendinosus expansion repair of massive rotator cuff injury immobilization model can better simulate the clinical rotator cuff injury healing process, so it can be used as an ideal animal model for related research.

[Reconstruction of chronic Achilles tendon rupture with flexor hallucis longus tendon harvested using a minimally invasive technique].

PubMed

Miao, Xudong; Wu, Yongping; Tao, Huimin; Yang, Disheng

2011-07-01

To evaluate the effectiveness of flexor hallucis longus tendon harvested using a minimally invasive technique in reconstruction of chronic Achilles tendon rupture. Between July 2006 and December 2009, 22 patients (22 feet) with chronic Achilles tendon rupture were treated, including 16 males and 6 females with a median age of 48 years (range, 28-65 years). The disease duration was 27-1,025 days (median, 51 days). Twenty-one patients had hooflike movement's history and 1 patient had no obvious inducement. The result of Thompson test was positive in 22 cases. The score was 53.04 +/- 6.75 according to American Orthopedic Foot and Ankle Society (AOFAS) ankle and hindfoot score system. MRI indicated that the gap of the chronic Achilles tendon rupture was 4.2-8.0 cm. A 3 cm-long incision was made vertically in the plantar aspect of the midfoot and a 1 cm-long transverse incision was made in a plantar flexor crease at the base of the great toe to harvest flexor hallucis longus tendon. The flexor hallucis longus tendon was 10.5-13.5 cm longer from tuber calcanei to the end of the Achilles tendon, and then the tendon was fixed to the tuber calcanei using interface screws or anchor nail after they were woven to form reflexed 3-bundle and sutured. Wound healed by first intention in all patients and no early complication occurred. Twenty-two patients were followed up 12-42 months (mean, 16.7 months). At 12 months after operation, The AOFAS ankle and hindfoot score was 92.98 +/- 5.72, showing significant difference when compared with that before operation (t= -40.903, P=0.000). The results were excellent in 18 cases, good in 2 cases, and fair in 2 cases with an excellent and good rate of 90.9%. No sural nerve injury, posterior tibial nerve injury, plantar painful scar, medial plantar nerve injury, and lateral plantar nerve injury occurred. Chronic Achilles tendon rupture reconstruction with flexor hallucis longus tendon harvested using a minimally invasive technique offers a desirable outcome in operative recovery, tendon fixation, and complications.

Quantification of Internal Stress-Strain Fields in Human Tendon: Unraveling the Mechanisms that Underlie Regional Tendon Adaptations and Mal-Adaptations to Mechanical Loading and the Effectiveness of Therapeutic Eccentric Exercise

PubMed Central

Maganaris, Constantinos N.; Chatzistergos, Panagiotis; Reeves, Neil D.; Narici, Marco V.

2017-01-01

By virtue of their anatomical location between muscles and bones, tendons make it possible to transform contractile force to joint rotation and locomotion. However, tendons do not behave as rigid links, but exhibit viscoelastic tensile properties, thereby affecting the length and contractile force in the in-series muscle, but also storing and releasing elastic stain energy as some tendons are stretched and recoiled in a cyclic manner during locomotion. In the late 90s, advancements were made in the application of ultrasound scanning that allowed quantifying the tensile deformability and mechanical properties of human tendons in vivo. Since then, the main principles of the ultrasound-based method have been applied by numerous research groups throughout the world and showed that tendons increase their tensile stiffness in response to exercise training and chronic mechanical loading, in general, by increasing their size and improving their intrinsic material. It is often assumed that these changes occur homogenously, in the entire body of the tendon, but recent findings indicate that the adaptations may in fact take place in some but not all tendon regions. The present review focuses on these regional adaptability features and highlights two paradigms where they are particularly evident: (a) Chronic mechanical loading in healthy tendons, and (b) tendinopathy. In the former loading paradigm, local tendon adaptations indicate that certain regions may “see,” and therefore adapt to, increased levels of stress. In the latter paradigm, local pathological features indicate that certain tendon regions may be “stress-shielded” and degenerate over time. Eccentric exercise protocols have successfully been used in the management of tendinopathy, without much sound understanding of the mechanisms underpinning their effectiveness. For insertional tendinopathy, in particular, it is possible that the effectiveness of a loading/rehabilitation protocol depends on the topography of the stress created by the exercise and is not only reliant upon the type of muscle contraction performed. To better understand the micromechanical behavior and regional adaptability/mal-adaptability of tendon tissue it is important to estimate its internal stress-strain fields. Recent relevant advancements in numerical techniques related to tendon loading are discussed. PMID:28293194

FROM ACUTE ACHILLES TENDON RUPTURE TO RETURN TO PLAY - A CASE REPORT EVALUATING RECOVERY OF TENDON STRUCTURE, MECHANICAL PROPERTIES, CLINICAL AND FUNCTIONAL OUTCOMES.

PubMed

Zellers, Jennifer A; Cortes, Daniel H; Silbernagel, Karin Grävare

2016-12-01

Achilles tendon rupture results in significant functional deficits regardless of treatment strategy (surgical versus non-surgical intervention). Recovery post-rupture is highly variable, making comprehensive patient assessment critical. Assessment tools may change along the course of recovery as the patient progresses - for instance, moving from a seated heel-rise to standing heel-rise to jump testing. However, tools that serve as biomarkers for early recovery may be particularly useful in informing clinical decision-making. The purpose of this case report was to describe the progress of a young, athletic individual following Achilles tendon rupture managed non-surgically, using patient reported and functional performance outcome measures and comprehensively evaluating Achilles tendon structure and function incorporating a novel imaging technique (cSWE). The subject is a 26 year-old, female basketball coach who sustained an Achilles tendon rupture and was managed non-surgically. The subject was able to steadily progress using a gradual tendon loading treatment approach well-supported by the literature. Multiple evaluative techniques including the addition of diagnostic ultrasound imaging and continuous shear wave elastography (cSWE) to standard clinical tests and measures were used to assess patient-reported symptoms, tendon structure, and tendon functional performance. Five assessments were performed over the course of 2-14 months post-rupture. By the 14-month follow-up, the subject had achieved full self-reported function. Tendon structural and mechanical properties showed similar shear modulus by 14 months, however, viscosity continued to be lower and tendon length longer on the ruptured side. Functional performance, evidenced by the heel-rise test and jump tests, also showed a positive trajectory, however, deficits of 12-28% remained between ruptured and non-ruptured sides at 14 months. This case report outlines comprehensive outcomes assessment in an athletic individual following non-surgically managed Achilles tendon rupture using a wide variety of tools that capture different aspects of tendon health. Interestingly, the course of recovery of patient symptoms, functional performance, and tendon structure do not occur in the same time frame. Therefore, it is important to assess patient outcomes using multiple outcome measures encompassing different aspects of patient performance to ensure the patient is progressing steadily with rehabilitation. Level 4.

Associations between abnormal ultrasound color Doppler measures and tendon pain symptoms in badminton players during a season: a prospective cohort study.

PubMed

Boesen, Anders Ploug; Boesen, Morten Ilum; Torp-Pedersen, Soren; Christensen, Robin; Boesen, Lars; Hölmich, Per; Nielsen, Michael Bachmann; Koenig, Merete Juhl; Hartkopp, Andreas; Ellegaard, Karen; Bliddal, Henning; Langberg, Henning

2012-03-01

Color Doppler ultrasound is widely used to examine intratendinous flow in individuals with overuse tendon problems, but the association between color Doppler and pain is still unclear. Intratendinous flow is present and associated with pain in badminton players, and intratendinous flow and pain increase during a badminton season. Cohort study (prognosis); Level of evidence, 2. Ninety-five semiprofessional badminton players were included in the study at a tournament at the start of the badminton season. All players were interviewed regarding pain. The anterior knee tendons and Achilles tendons were studied. Each tendon was scored using a quantitative grading system (grades 0-5) and a qualitative scoring system (color fraction) using color Doppler ultrasound. Eight months later, 86 of the players (91%) were retested by the same investigators during an equivalent badminton tournament (including 1032 tendon regions; 86 players with 4 tendons each with 3 regions), thus forming the study group. At the start of the season, 24 players (28%) experienced pain in 37 tendons (11%), and at the end of the season, 31 players (36%) experienced pain in 51 tendons (15%), which was a statistically significant increase (P = .0002). Abnormal flow was found in 230 tendon regions in 71 players (83%) at the start of the season compared with 78 tendon regions in 41 players (48%) at the follow-up. The decrease in abnormal flow was statistically significant (P < .0001). Of the 37 painful tendons at the start of the season, 25 had abnormal flow (68%). In contrast, 131 tendons (85%) with abnormal flow at the start of the season were pain free. At the end of the season, 18 of the 51 painful tendons (35%) had abnormal flow. Ninety-six of the 131 pain-free tendons (73%) with abnormal flow at the start of the season were normalized (no pain and normal flow) at the end of the season. It was not possible to verify any association between intratendinous flow and pain at the start of the season or at the follow-up (end of the season). Intratendinous flow at the start of the season could not predict symptomatic outcome at the end of the season. The decrease in Doppler flow during the season might suggest that intratendinous flow could be part of a physiological adaptive response to loading and that intratendinous flow as previously believed is not always a sign of pathological changes.

Bilateral Patellar Tendon Rupture

DTIC Science & Technology

2009-07-01

Bilateral patellar tendon rupture Military Medicine Radiology Corner, Volume 173, July, 2009...Radiology Corner Bilateral patellar tendon rupture (#37) Guarantor: 2dLt Ramon A. Riojas, USAF, MSC1 Contributors: 2dLt Ramon A. Riojas...with the abbreviated answer in the July 2009 issue. 1 The authors present a case of bilateral patellar tendon rupture in an active duty male exiting

Tendon and ligament imaging

PubMed Central

Hodgson, R J; O'Connor, P J; Grainger, A J

2012-01-01

MRI and ultrasound are now widely used for the assessment of tendon and ligament abnormalities. Healthy tendons and ligaments contain high levels of collagen with a structured orientation, which gives rise to their characteristic normal imaging appearances as well as causing particular imaging artefacts. Changes to ligaments and tendons as a result of disease and injury can be demonstrated using both ultrasound and MRI. These have been validated against surgical and histological findings. Novel imaging techniques are being developed that may improve the ability of MRI and ultrasound to assess tendon and ligament disease. PMID:22553301

The plantaris tendon: a narrative review focusing on anatomical features and clinical importance.

PubMed

Spang, C; Alfredson, H; Docking, S I; Masci, L; Andersson, G

2016-10-01

In recent years, the plantaris tendon has been implicated in the development of chronic painful mid-portion Achilles tendinopathy. In some cases, a thickened plantaris tendon is closely associated with the Achilles tendon, and surgical excision of the plantaris tendon has been reported to be curative in patients who have not derived benefit following conservative treatment and surgical interventions. The aim of this review is to outline the basic aspects of, and the recent research findings, related to the plantaris tendon, covering anatomical and clinical studies including those dealing with histology, imaging and treatment. Cite this article: Bone Joint J 2016;98-B:1312-19. ©2016 The British Editorial Society of Bone & Joint Surgery.

Differences in tendon properties in elite badminton players with or without patellar tendinopathy.

PubMed

Couppé, C; Kongsgaard, M; Aagaard, P; Vinther, A; Boesen, M; Kjaer, M; Magnusson, S P

2013-03-01

The aim of this study was to examine the structural and mechanical properties of the patellar tendon in elite male badminton players with and without patellar tendinopathy. Seven players with unilateral patellar tendinopathy (PT group) on the lead extremity (used for forward lunge) and nine players with no current or previous patellar tendinopathy (CT group) were included. Magnetic resonance imaging was used to assess distal patellar tendon dimensions. Patellar tendon mechanical properties were assessed using simultaneous tendon force and deformation measurements. Distal tendon cross-sectional area (CSA) normalized for body weight (mm(2) /kg(2/3) ) was lower in the PT group compared with the CT group on both the non-lead extremity (6.1 ± 0.3 vs 7.4 ± 0.2, P < 0.05) and the lead extremity (6.5 ± 0.6 vs 8.4 ± 0.3, P < 0.05). Distal tendon stress was higher in the PT group compared with the CT group for both the non-lead extremity (31 ± 1 vs 27 ± 1 MPa, P < 0.05) and the lead extremity (32 ± 3 vs 21 ± 3 MPa, P < 0.01). Conclusively, the PT group had smaller distal patellar tendon CSA on both the injured (lead extremity) and the uninjured side (non-lead extremity) compared with the CT group. Subsequently, the smaller CSA yielded a greater distal patellar tendon stress in the PT group. Therefore, a small tendon CSA may predispose to the development of tendinopathy. © 2012 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

Aging Does Not Alter Tendon Mechanical Properties During Homeostasis, but does Impair Flexor Tendon Healing

PubMed Central

Ackerman, Jessica E.; Bah, Ibrahima; Jonason, Jennifer H.; Buckley, Mark R.; Loiselle, Alayna E.

2017-01-01

Aging is an important factor in disrupted homeostasis of many tissues. While an increased incidence of tendinopathy and tendon rupture are observed with aging, it is unclear whether this is due to progressive changes in tendon cell function and mechanics over time, or an impaired repair reaction from aged tendons in response to insult or injury. In the present study we examined changes in the mechanical properties of Flexor Digitorum Longus (FDL), Flexor Carpi Ulnaris (FCU), and tail fascicles in both male and female C57Bl/6 mice between 3-27 months of age to better understand the effects of sex and age on tendon homeostasis. No change in max load at failure was observed in any group over the course of aging, although there were significant decreases in toe and linear stiffness in female mice from 3-months to 15, and to 22-27-months. No changes in cell proliferation were observed with aging, although an observable decrease in cellularity occurred in 31-month old tendons. Given that aging did not dramatically alter tendon mechanical homeostasis we hypothesized that a disruption in tendon homeostasis, via acute injury would result in an impaired healing response. Significant decreases in max load, stiffness, and yield load were observed in repairs of 22-month old mice, relative to 4-month old mice. No changes in cell proliferation were observed between young and aged, however a dramatic loss of bridging collagen extracellular matrix was observed in aged repairs suggest that matrix production, but not cell proliferation leads to impaired tendon healing with aging. PMID:28419543

Multiple variations of the tendons of the anatomical snuffbox

PubMed Central

Thwin, San San; Zaini, Fazlin; Than, Myo

2014-01-01

INTRODUCTION Multiple tendons of the abductor pollicis longus (APL) in the anatomical snuffbox of the wrist can lead to the development of de Quervain's syndrome, which is caused by stenosing tenosynovitis. A cadaveric study was performed to establish the variations present in the tendons of the anatomical snuffbox in a Malaysian population, in the hope that this knowledge would aid clinical investigation and surgical treatment of de Quervain's tenosynovitis. METHODS Routine dissection of ten upper limbs was performed to determine the variations in the tendons of the anatomical snuffbox of the wrist. RESULTS In all the dissected upper limbs, the APL tendon of the first extensor compartment was found to have several (3–14) tendon slips. The insertion of the APL tendon slips in all upper limbs were at the base of the first metacarpal bone, trapezium and fascia of the opponens pollicis muscle; however, in seven specimens, they were also found to be attached to the fleshy belly of the abductor pollicis brevis muscle. In two specimens, double tendons of the extensor pollicis longus located in the third extensor compartment were inserted into the capsule of the proximal interphalangeal joints before being joined to the extensor expansion. In two other specimens, the first extensor compartment had two osseofibrous tunnels divided by a septum that separated the APL tendon from the extensor pollicis brevis tendon. CONCLUSION Multiple variations were found in the anatomical snuffbox region of the dissected upper limbs. Knowledge of these variations would be useful in interventional radiology and orthopaedic surgery. PMID:24452976

A Comparison of the Quasi-static Mechanical and Nonlinear Viscoelastic Properties of the Human Semitendinosus and Gracilis Tendons

PubMed Central

Abramowitch, Steven D.; Zhang, Xiaoyan; Curran, Molly; Kilger, Robert

2010-01-01

Background Over fifty-percent of anterior cruciate ligament reconstructions are performed using semitendinosus and gracilis tendon autografts. Despite their increased use, there remains little quantitative data on their mechanical behavior. Therefore, the objective of this study was to investigate the quasi-static mechanical and nonlinear viscoelastic properties of human semitendinosus and gracilis tendons, as well as the variation of these properties along their length. Methods Specimens were subjected to a series of uniaxial tensile tests: one-hour static stress-relaxation test, 30-cycle cyclic stress-relaxation test and load to failure test. To describe the nonlinear viscoelastic behavior, the quasi-linear viscoelastic theory was utilized to model data from the static stress relaxation experiment. Findings The constants describing the viscoelastic behavior were similar between the proximal and distal halves of the gracilis tendon. The proximal half of the semitendinosus tendon, however, had a greater viscous response than its distal half, which was also significantly higher than the proximal gracilis tendon. In terms of the quasi-static mechanical properties, the properties were similar between the proximal and distal halves of the semitendinosus tendon. However, the distal gracilis tendon showed a significantly higher tangent modulus and ultimate stress compared to its proximal half, which was also significantly higher than the distal semitendinosus tendon. Interpretation The results of this study demonstrate differences between the semitendinosus and gracilis tendons in terms of their quasi-static mechanical and nonlinear viscoelastic properties. These results are important for establishing surgical preconditioning protocols and graft selection. PMID:20092917

High-resolution US and MR imaging of peroneal tendon injuries.

PubMed

Taljanovic, Mihra S; Alcala, Jennifer N; Gimber, Lana H; Rieke, Joshua D; Chilvers, Margaret M; Latt, L Daniel

2015-01-01

Injuries of the peroneal tendon complex are common and should be considered in every patient who presents with chronic lateral ankle pain. These injuries occur as a result of trauma (including ankle sprains), in tendons with preexisting tendonopathy, and with repetitive microtrauma due to instability. The peroneus brevis and peroneus longus tendons are rarely torn simultaneously. Several anatomic variants, including a flat or convex fibular retromalleolar groove, hypertrophy of the peroneal tubercle at the lateral aspect of the calcaneus, an accessory peroneus quartus muscle, a low-lying peroneus brevis muscle belly, and an os peroneum, may predispose to peroneal tendon injuries. High-resolution 1.5-T and 3-T magnetic resonance (MR) imaging with use of dedicated extremity coils and high-resolution ultrasonography (US) with high-frequency linear transducers and dynamic imaging are proved to adequately depict the peroneal tendons for evaluation and can aid the orthopedic surgeon in injury management. An understanding of current treatment approaches for partial- and full-thickness peroneal tendon tears, subluxation and dislocation of these tendons with superior peroneal retinaculum (SPR) injuries, intrasheath subluxations, and peroneal tendonopathy and tenosynovitis can help physicians achieve a favorable outcome. Patients with low functional demands do well with conservative treatment, while those with high functional demands may benefit from surgery if nonsurgical treatment is unsuccessful. Radiologists should recognize the normal anatomy and specific pathologic conditions of the peroneal tendons at US and MR imaging and understand the various treatment options for peroneal tendon and SPR superior peroneal retinaculum injuries. Online supplemental material is available for this article. RSNA, 2015

Slack length of gastrocnemius medialis and Achilles tendon occurs at different ankle angles.

PubMed

Hug, François; Lacourpaille, Lilian; Maïsetti, Olivier; Nordez, Antoine

2013-09-27

Although muscle-tendon slack length is a crucial parameter used in muscle models, this is one of the most difficult measures to estimate in vivo. The aim of this study was to determine the onset of the rise in tension (i.e., slack length) during passive stretching in both Achilles tendon and gastrocnemius medialis. Muscle and tendon shear elastic modulus was measured by elastography (supersonic shear imaging) during passive plantarflexion (0° and 90° of knee angle, 0° representing knee fully extended, in a random order) in 9 participants. The within-session repeatability of the determined slack length was good at 90° of knee flexion (SEM=3.3° and 2.2° for Achilles tendon and gastrocnemius medialis, respectively) and very good at 0° of knee flexion (SEM=1.9° and 1.9° for Achilles tendon and gastrocnemius medialis, respectively). The slack length of gastrocnemius medialis was obtained at a significantly lower plantarflexed angle than for Achilles tendon at both 0° (P<0.0001; mean difference=19.4±3.8°) and 90° of knee flexion (P<0.0001; mean difference=25.5±7.6°). In conclusion, this study showed that the joint angle at which the tendon falls slack can be experimentally determined using supersonic shear imaging. The slack length of gastrocnemius medialis and Achilles tendon occurred at different joint angles. Although reporting this result is crucial to a better understanding of muscle-tendon interactions, further experimental investigations are required to explain this result. Copyright © 2013 Elsevier Ltd. All rights reserved.

Whole-body vibration training induces hypertrophy of the human patellar tendon.

PubMed

Rieder, F; Wiesinger, H-P; Kösters, A; Müller, E; Seynnes, O R

2016-08-01

Animal studies suggest that regular exposure to whole-body vibration (WBV) induces an anabolic response in bone and tendon. However, the effects of this type of intervention on human tendon properties and its influence on the muscle-tendon unit function have never been investigated. The aim of this study was to investigate the effect of WBV training on the patellar tendon mechanical, material and morphological properties, the quadriceps muscle architecture and the knee extension torque-angle relationship. Fifty-five subjects were randomized into either a vibration, an active control, or an inactive control group. The active control subjects performed isometric squats on a vibration platform without vibration. Muscle and tendon properties were measured using ultrasonography and dynamometry. Vibration training induced an increase in proximal (6.3%) and mean (3.8%) tendon cross-sectional area, without any appreciable change in tendon stiffness and modulus or in muscle architectural parameters. Isometric torque at a knee angle of 90° increased in active controls (6.7%) only and the torque-angle relation remained globally unchanged in all groups. The present protocol did not appreciably alter knee extension torque production or the musculo-tendinous parameters underpinning this function. Nonetheless, this study shows for the first time that WBV elicits tendon hypertrophy in humans. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Achilles tendon structure improves on UTC imaging over a 5-month pre-season in elite Australian football players.

PubMed

Docking, S I; Rosengarten, S D; Cook, J

2016-05-01

Pre-season injuries are common and may be due to a reintroduction of training loads. Tendons are sensitive to changes in load, making them vulnerable to injury in the pre-season. This study investigated changes in Achilles tendon structure on ultrasound tissue characterization (UTC) over the course of a 5-month pre-season in elite male Australian football players. Eighteen elite male Australian football players with no history of Achilles tendinopathy and normal Achilles tendons were recruited. The left Achilles tendon was scanned with UTC to quantify the stability of the echopattern. Participants were scanned at the start and completion of a 5-month pre-season. Fifteen players remained asymptomatic over the course of the pre-season. All four echo-types were significantly different at the end of the pre-season, with the overall echopattern suggesting an improvement in Achilles tendon structure. Three of the 18 participants developed Achilles tendon pain that coincided with a change in the UTC echopattern. This study demonstrates that the UTC echopattern of the Achilles tendon improves over a 5-month pre-season training period, representing increased fibrillar alignment. However, further investigation is needed to elucidate with this alteration in the UTC echopattern results in improved tendon resilience and load capacity. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Peroneal Tendon Reconstruction and Coverage for Treatment of Septic Peroneal Tenosynovitis: A Devastating Complication of Lateral Ankle Ligament Reconstruction With a Tendon Allograft.

PubMed

Schade, Valerie L; Harsha, Wayne; Rodman, Caitlin; Roukis, Thomas S

2016-01-01

Septic peroneal tenosynovitis is a rare and significant challenge. A search of peer-reviewed published studies revealed only 5 case reports to guide treatment, none of which resulted in significant loss of both peroneal tendons necessitating reconstruction. No clear guidance is available regarding how to provide reliable reconstruction of both peroneal tendons after a significant loss secondary to septic tenosynovitis. In the present report, we describe the case of a young, active-duty soldier who underwent lateral ankle ligament reconstruction with a tendon allograft whose postoperative course was complicated by septic peroneal tenosynovitis resulting in significant loss of both peroneal tendons. Reconstruction was achieved in a staged fashion with the use of silicone rods and external fixation to maintain physiologic tension and preserve peroneal tendon function, followed by reconstruction of both peroneal tendons and the superior peroneal retinaculum with a tensor fascia lata autograft. Soft tissue coverage was obtained with an anterolateral thigh free tissue transfer and a split-thickness skin graft. The patient returned to full activity as an active-duty soldier with minimal pain and no instability of the right lower extremity. The muscle strength of both peroneal tendons remained at 5 of 5, and no objective findings of ankle instability were seen at 3.5 years postoperatively. Published by Elsevier Inc.

Infrapatellar fat pad disruption: a radiographic sign of patellar tendon rupture.

PubMed

Chin, Kingsley R; Sodl, Jeffrey F

2005-11-01

After knee trauma, radiographs showing patella alta supercede other signs that suggest patellar tendon rupture. However, without patella alta the diagnosis may be missed. A standard lateral radiograph with the knee flexed showed the infrapatellar fat pad as a dark band with a smooth contour. Our pilot study identified a disruption of the fat pad contour as a radiographic sign of tendon rupture. Two blinded reviewers independently analyzed randomly selected lateral radiographs of the knees of 14 patients with knee injuries. Seven patients had confirmed ruptures diagnosed at surgery, and the other patients had different diagnoses. There were 12 men and two women with an average age of 49 years (range, 20-81 years). One observer detected five of the seven disrupted tendons and six of the seven intact tendons. The other observer detected six of the seven disrupted tendons and all seven intact tendons. Disruption in the contour of the infrapatellar fat pad on routine lateral view radiographs was a reasonably reliable sign of patellar tendon rupture. Diagnostic accuracy should increase when used with the patient's history, physical examination, and other radiographic signs. Absence of this sign should not supersede other suggestive signs of patella tendon rupture. Diagnostic study, Level II (development of diagnostic criteria on consecutive patients--with universally applied reference "gold" standard). See the Guidelines for Authors for a complete description of levels of evidence.

Basic FGF or VEGF gene therapy corrects insufficiency in the intrinsic healing capacity of tendons

PubMed Central

Tang, Jin Bo; Wu, Ya Fang; Cao, Yi; Chen, Chuan Hao; Zhou, You Lang; Avanessian, Bella; Shimada, Masaru; Wang, Xiao Tian; Liu, Paul Y.

2016-01-01

Tendon injury during limb motion is common. Damaged tendons heal poorly and frequently undergo unpredictable ruptures or impaired motion due to insufficient innate healing capacity. By basic fibroblast growth factor (bFGF) or vascular endothelial growth factor (VEGF) gene therapy via adeno-associated viral type-2 (AAV2) vector to produce supernormal amount of bFGF or VEGF intrinsically in the tendon, we effectively corrected the insufficiency of the tendon healing capacity. This therapeutic approach (1) resulted in substantial amelioration of the low growth factor activity with significant increases in bFGF or VEGF from weeks 4 to 6 in the treated tendons (p < 0.05 or p < 0.01), (2) significantly promoted production of type I collagen and other extracellular molecules (p < 0.01) and accelerated cellular proliferation, and (3) significantly increased tendon strength by 68–91% from week 2 after AAV2-bFGF treatment and by 82–210% from week 3 after AAV2-VEGF compared with that of the controls (p < 0.05 or p < 0.01). Moreover, the transgene expression dissipated after healing was complete. These findings show that the gene transfers provide an optimistic solution to the insufficiencies of the intrinsic healing capacity of the tendon and offers an effective therapeutic possibility for patients with tendon disunion. PMID:26865366

Utility of an allograft tendon for scoliosis correction via the costo-transverse foreman.

PubMed

Sun, Dong; McCarthy, Michael; Dooley, Adam C; Ramakrishnaiah, Raghu H; Shelton, R Shane; McLaren, Sandra G; Skinner, Robert A; Suva, Larry J; McCarthy, Richard E

2017-01-01

Current convex tethering techniques for treatment of scoliosis have centered on anterior convex staples or polypropylene tethers. We hypothesized that an allograft tendon tether inserted via the costo-transverse foramen would correct an established spinal deformity. In the pilot study, six 8-week-old pigs underwent allograft tendon tethering via the costo-transverse foreman or sham to test the strength of the transplanted tendon to retard spine growth. After 4 months, spinal deformity in three planes was induced in all animals with allograft tendons. In the treatment study, the allograft tendon tether was used to treat established scoliosis in 11 8-week-old pigs (spinal deformity > 50°). Once the deformity was observed (4 months) animals were assigned to either no treatment group or allograft tendon tether group and progression assessed by monthly radiographs. At final follow-up, coronal Cobb angle and maximum vertebral axial rotation of the treatment group was significantly smaller than the non-treatment group, whereas sagittal kyphosis of the treatment group was significantly larger than the non-treatment group. In sum, a significant correction was achieved using a unilateral allograft tendon spinal tether, suggesting that an allograft tendon tethering approach may represent a novel fusion-less procedure to correct idiopathic scoliosis. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:183-192, 2017. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Analysis of achilles tendon vascularity with second-generation contrast-enhanced ultrasound.

PubMed

Genovese, Eugenio; Ronga, Mario; Recaldini, Chiara; Fontana, Federico; Callegari, Leonardo; Maffulli, Nicola; Fugazzola, Carlo

2011-01-01

To compare morphological, power Doppler, and contrast-enhanced ultrasound (CEUS) features of the Achilles tendon between asymptomatic athletes and athletes who had undergone surgical repair of a previous rupture. Twenty-four athletes were divided in two groups (A and B). Group A included 14 patients with a median age of 32 years (range 27 to 47 years) who had undergone surgical repair for unilateral Achilles tendon rupture. Group B (control group) included 10 subjects with a median age of 34 years (range 27 to 40 years) with no previous or present history of tendinopathy. All patients were evaluated with ultrasound, power Doppler, and CEUS with second-generation contrast agent. We studied the uninjured Achilles tendon in athletes of group A and either the left or the right Achilles tendon of the athletes in group B. CEUS showed a significantly greater ability to detect a greater number of vascular spots within the uninjured tendon of group A compared to group B (<0.05). In athletes who had suffered a tear of an Achilles tendon, CEUS detected small vessels that were not identified by power Doppler ultrasound in the uninjured contralateral Achilles tendon. CEUS is useful to evaluate vascularity not detected by other imaging techniques. Vascularity in the uninjured tendon seems to be increased in patients who had a previous rupture. Copyright © 2011 Wiley Periodicals, Inc.

Alterations in tendon microenvironment in response to mechanical load: potential molecular targets for treatment strategies

PubMed Central

Fouda, Mohamed B; Thankam, Finosh G; Dilisio, Matthew F; Agrawal, Devendra K

2017-01-01

Rotator cuff (RC) tendons could beinflicted in many ways with an eventual outcome of pain, weakness and disability, which represent a large burden on health care cost. However, optimal healing, either conservatively or with surgical intervention, remains an issue that needs further investigation. Disorders of the RC tendons may result from external factors like trauma, or internal factors through physiologic and metabolic derangement. Most RC tendon disorders may be asymptomatic and may result from an over-activity of the inflicted shoulder and its tendons. Such tendon disorders are poorly diagnosed since patients do not seek medical attention until pain or weakness ensue. Immunological and biochemical events in RC disorders due to mechanical intolerance have not been investigated. Generally, the mechanical load drives normal physiological properties of the tendon. But, mechanical overload/burden exerts stress on tenocytes, and disrupts the tendon microenvironment by triggering a multitude of signaling pathways leading to extracellular matrix remodeling, disorganization, alteration in collagen composition and apoptosis. These events result in weak tendon which is highly susceptible to rupture or tear. In this article, we critically reviewed the intrinsic signaling pathways that are excessively triggered by continuous mechanical load and the counteracting physiological responses and associated derangements. The elucidation of the molecular events underlying mechanical stress-induced symptomatic/asymptomatic tendinopathy could provide information on potential target sites for translational application in the management of rotator cuff disorders. PMID:29118899

Supraspinatus tendinosis associated with biceps brachii tendon displacement in a dog.

PubMed

Fransson, Boel A; Gavin, Patrick R; Lahmers, Kevin K

2005-11-01

A 4-year-old spayed female Australian Cattle Dog (Blue Heeler) was evaluated because of right forelimb lameness of 5 months' duration. Orthopedic evaluation revealed signs of pain localized to the cranial aspects of both shoulder joints. Via magnetic resonance imaging, the mass of the supraspinatus tendon insertion in both shoulder joints was increased, compared with findings in cadavers of clinically normal dogs; additional imaging procedures revealed that, compared with clinically normal tendons, the tendon had increased signal intensity that was consistent with increased fluid content. The increased supraspinatus tendon mass in each shoulder joint was associated with medial displacement of the biceps brachii tendon, which was more severe in the right limb. Arthroscopic evaluations of both shoulder joints revealed no abnormalities. The dog underwent surgery, and the abnormal parts of the tendons were resected. The most prominent finding on histologic examination of excised tissues was severe myxomatous degeneration. The lameness resolved, and at 22 months after surgery, the dog was reported to have had no recurrence of lameness. The clinical signs and histologic appearance of the tendons in this dog strongly resemble findings associated with tendinosis in humans. Decompression of the biceps brachii tendon may have contributed to the successful outcome after surgery in this dog. Supraspinatus tendinosis should be considered among the differential diagnoses in dogs with uni- or bilateral forelimb lameness.

Fatigue loading of tendon

PubMed Central

Shepherd, Jennifer H; Screen, Hazel R C

2013-01-01

Tendon injuries, often called tendinopathies, are debilitating and painful conditions, generally considered to develop as a result of tendon overuse. The aetiology of tendinopathy remains poorly understood, and whilst tendon biopsies have provided some information concerning tendon appearance in late-stage disease, there is still little information concerning the mechanical and cellular events associated with disease initiation and progression. Investigating this in situ is challenging, and numerous models have been developed to investigate how overuse may generate tendon fatigue damage and how this may relate to tendinopathy conditions. This article aims to review these models and our current understanding of tendon fatigue damage. We review the strengths and limitations of different methodologies for characterizing tendon fatigue, considering in vitro methods that adopt both viable and non-viable samples, as well as the range of different in vivo approaches. By comparing data across model systems, we review the current understanding of fatigue damage development. Additionally, we compare these findings with data from tendinopathic tissue biopsies to provide some insights into how these models may relate to the aetiology of tendinopathy. Fatigue-induced damage consistently highlights the same microstructural, biological and mechanical changes to the tendon across all model systems and also correlates well with the findings from tendinopathic biopsy tissue. The multiple testing routes support matrix damage as an important contributor to tendinopathic conditions, but cellular responses to fatigue appear complex and often contradictory. PMID:23837793

The Achilles Tendon Insertion is Crescent-shaped: An In Vitro Anatomic Investigation

PubMed Central

Arentz, Sabine; Nauck, Tanja; Dorn-Lange, Nadja V.; Konerding, Moritz A.

2008-01-01

Anatomic and operative textbooks and current literature do not clearly describe the Achilles tendon interface to the calcaneal tuberosity. We dissected 51 specimens to identify the detailed anatomy of the Achilles tendon insertion. Achilles tendon fascicles expanded from the anterior aspect of the distal Achilles tendon over the retrocalcaneal bursa to the anterior part of the Haglund’s tuberosity in nearly half of the specimens. The insertion of the transverse section of the Achilles tendon regularly had a crescent-shape corresponding to the posterior calcaneal prominence. In transverse sections, all specimens had a curved appearance with a radius of curvature ranging from 13.8 mm to 43.6 mm (mean, 20.4 mm) and Achilles tendon extensions to the lateral and medial calcaneal surfaces reached 1.0 mm (mean) and 3.5 mm (mean) anterior in relation to the most posterior point of the calcaneal tuberosity. Knowledge of the arcuate configuration and of the medial and lateral extensions of the plantaris and the Achilles tendon insertion with respect to the transverse plane is important to avoid iatrogenic complications during resection of Haglund’s tuberosity. PMID:18506561

Effect of Micro-RNA on Tenocytes and Tendon-Related Gene Expression: A Systematic Review.

PubMed

Dubin, Jeremy A; Greenberg, Daniel R; Iglinski-Benjamin, Kag C; Abrams, Geoffrey D

2018-06-06

The purpose of the review was to synthesize the current literature regarding the effect of miRNA on biological processes known to be involved in tendon and tenocyte development and homeostasis. Using multiple databases, a systematic review was performed with a customized search term crafted to identify any study examining micro-RNA in relation to tendon and/or tenocytes. Results were classified based on the following categories: gene expression, tenocyte development and differentiation, tendon tissue repair, and tenocyte senescence. A total of 3,112 potentially relevant studies were reviewed, and after exclusion criteria was applied, 15 investigations were included in the final analysis. There were 14 specific miRNA included in this review, with 11 studies reporting on tendon-related gene expression, five reporting on tendon development and/or tenocyte differentiation, six reporting on tendon tissue repair, and five reporting on tenocyte senescence. The miR-29 family was the most commonly reported micro-RNA in the investigation. We also report on a number of micro-RNA which are associated with both positive and negative effects on tendon homeostasis. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Evaluating Changes in Tendon Crimp with Fatigue Loading as an ex vivo Structural Assessment of Tendon Damage

PubMed Central

Freedman, Benjamin R.; Zuskov, Andrey; Sarver, Joseph J.; Buckley, Mark R.; Soslowsky, Louis J.

2015-01-01

The complex structure of tendons relates to their mechanical properties. Previous research has associated the waviness of collagen fibers (crimp) during quasi-static tensile loading to tensile mechanics, but less is known about the role of fatigue loading on crimp properties. In this study (IACUC approved), mouse patellar tendons were fatigue loaded while an integrated plane polariscope simultaneously assessed crimp properties. We demonstrate a novel structural mechanism whereby tendon crimp amplitude and frequency are altered with fatigue loading. In particular, fatigue loading increased the crimp amplitude across the tendon width and length, and these structural alterations were shown to be both region and load dependent. The change in crimp amplitude was strongly correlated to mechanical tissue laxity (defined as the ratio of displacement and gauge length relative to the first cycle of fatigue loading assessed at constant load throughout testing), at all loads and regions evaluated. Together, this study highlights the role of fatigue loading on tendon crimp properties as a function of load applied and region evaluated, and offers an additional structural mechanism for mechanical alterations that may lead to ultimate tendon failure. PMID:25773654

Current Concepts in Examination and Treatment of Elbow Tendon Injury

PubMed Central

Ellenbecker, Todd S.; Nirschl, Robert; Renstrom, Per

2013-01-01

Context: Injuries to the tendons of the elbow occur frequently in the overhead athlete, creating a significant loss of function and dilemma to sports medicine professionals. A detailed review of the anatomy, etiology, and pathophysiology of tendon injury coupled with comprehensive evaluation and treatment information is needed for clinicians to optimally design treatment programs for rehabilitation and prevention. Evidence Acquisitions: The PubMed database was searched in January 2012 for English-language articles pertaining to elbow tendon injury. Results: Detailed information on tendon pathophysiology was found along with incidence of elbow injury in overhead athletes. Several evidence-based reviews were identified, providing a thorough review of the recommended rehabilitation for elbow tendon injury. Conclusions: Humeral epicondylitis is an extra-articular tendon injury that is common in athletes subjected to repetitive upper extremity loading. Research is limited on the identification of treatment modalities that can reduce pain and restore function to the elbow. Eccentric exercise has been studied in several investigations and, when coupled with a complete upper extremity strengthening program, can produce positive results in patients with elbow tendon injury. Further research is needed in high-level study to delineate optimal treatment methods. PMID:24427389

Moderate treadmill running exercise prior to tendon injury enhances wound healing in aging rats

PubMed Central

Zhang, Jianying; Yuan, Ting; Wang, James H-C.

2016-01-01

The effect of exercise on wound healing in aging tendon was tested using a rat moderate treadmill running (MTR) model. The rats were divided into an MTR group that ran on a treadmill for 4 weeks and a control group that remained in cages. After MTR, a window defect was created in the patellar tendons of all rats and wound healing was analyzed. We found that MTR accelerated wound healing by promoting quicker closure of wounds, improving the organization of collagen fibers, and decreasing senescent cells in the wounded tendons when compared to the cage control. MTR also lowered vascularization, increased the numbers of tendon stem/progenitor cells (TSCs) and TSC proliferation than the control. Besides, MTR significantly increased the expression of stem cell markers, OCT-4 and Nanog, and tenocyte genes, Collagen I, Collagen III and tenomodulin, and down-regulated PPAR-γ, Collagen II and Runx-2 (non-tenocyte genes). These findings indicated that moderate exercise enhances healing of injuries in aging tendons through TSC based mechanisms, through which exercise regulates beneficial effects in tendons. This study reveals that appropriate exercise may be used in clinics to enhance tendon healing in aging patients. PMID:26885754

Tendon 'turnover lengthening' technique.

PubMed

Cerovac, S; Miranda, B H

2013-11-01

Tendon defect reconstruction is amongst the most technically challenging areas in hand surgery. Tendon substance deficiency reconstruction techniques include lengthening, grafting, two-stage reconstruction and tendon transfers, however each is associated with unique challenges over and above direct repair. We describe a novel 'turnover lengthening' technique for hand tendons that has successfully been applied to the repair of several cases, including a case of attritional flexor and traumatic extensor tendon rupture in two presented patients where primary tenorrhaphy was not possible. In both cases a good post-operative outcome was achieved, as the patients were happy having returned back to normal activities of daily living such that they were discharged 12 weeks post-operatively. Our technique avoids the additional morbidity and complications associated with grafting, transfers and two stage reconstructions. It is quick, simple and reproducible for defects not exceeding 3-4 cm, provides a means of immediate one stage reconstruction, no secondary donor site morbidity and does not compromise salvage by tendon transfer and/or two-stage reconstruction in cases of failure. To our knowledge no such technique has been previously been described to reconstruct such hand tendon defects. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

[Rupture of the tendon of the tibialis anterior muscle : Etiology, clinical symptoms and treatment].

PubMed

Waizy, H; Bouillon, B; Stukenborg-Colsman, C; Yao, D; Ettinger, S; Claassen, L; Plaass, C; Danniilidis, K; Arbab, D

2017-12-01

Ruptures of the tendon of the tibialis anterior muscle tend to occur in the context of degenerative impairments. This mainly affects the distal avascular portion of the tendon. Owing to the good compensation through the extensor hallucis longus and extensor digitorum muscles, diagnosis is often delayed. In addition to the clinical examination, magnetic resonance inaging (MRI) diagnostics are of particular importance, although damage or rupture of the tendon can also be demonstrated sonographically. Therapeutic measures include conservative or operative measures, depending on the clinical symptoms. Conservative stabilization of the ankle can be achieved by avoiding plantar flexion using a peroneal orthosis or an ankle-foot orthosis. Subsequent problems, such as metatarsalgia or overloading of the medial foot edge can be addressed by insoles or a corresponding shoe adjustment. An operative procedure is indicated when there is corresponding suffering due to pressure and functional impairment. The direct end-to-end reconstruction of the tendon is only rarely possible in cases of delayed diagnosis due to the degenerative situation and the retraction of the tendon stumps. Depending on the defect size and the tendon quality, various operative techniques, such as rotationplasty, free transplants or tendon transfer can be used.

Peroneal tendon disorders

PubMed Central

Davda, Kinner; Malhotra, Karan; O’Donnell, Paul; Singh, Dishan; Cullen, Nicholas

2017-01-01

Pathological abnormality of the peroneal tendons is an under-appreciated source of lateral hindfoot pain and dysfunction that can be difficult to distinguish from lateral ankle ligament injuries. Enclosed within the lateral compartment of the leg, the peroneal tendons are the primary evertors of the foot and function as lateral ankle stabilisers. Pathology of the tendons falls into three broad categories: tendinitis and tenosynovitis, tendon subluxation and dislocation, and tendon splits and tears. These can be associated with ankle instability, hindfoot deformity and anomalous anatomy such as a low lying peroneus brevis or peroneus quartus. A thorough clinical examination should include an assessment of foot type (cavus or planovalgus), palpation of the peronei in the retromalleolar groove on resisted ankle dorsiflexion and eversion as well as testing of lateral ankle ligaments. Imaging including radiographs, ultrasound and MRI will help determine the diagnosis. Treatment recommendations for these disorders are primarily based on case series and expert opinion. The aim of this review is to summarise the current understanding of the anatomy and diagnostic evaluation of the peroneal tendons, and to present both conservative and operative management options of peroneal tendon lesions. Cite this article: EFORT Open Rev 2017;2:281-292. DOI: 10.1302/2058-5241.2.160047 PMID:28736620

Closing the gap on Achilles tendon rupture: A cadaveric study quantifying the tendon apposition achieved with commonly used immobilisation practices.

PubMed

Collins, Ruaraidh; Sudlow, Alexis; Loizou, Constantinos; Loveday, David T; Smith, George

2018-04-01

The relative benefits of surgical and conservative treatment of Achilles tendon rupture are widely debated. With modern conservative management protocols, the re-rupture risk appears to fall to one similar to surgical repair with negligible loss of function. Conservative management typically employs a period of time in an equinus cast with sequential ankle dorsiflexion in a functional orthosis. The optimal duration of immobilisation and rate of dorsiflexion is unknown. We aimed to quantify the change in Achilles tendon approximation achieved in common immobilisation techniques to assist the design of rehabilitation protocols. Twelve fresh-frozen cadaveric specimens had 2.5cm of Achilles tendon excised. The gap between the tendon ends were measured via windowed full equinus casts and compared with functional boots with successively removed heel wedges. The greatest tendon apposition was achieved with the equinus cast. Each wedge removed decreased the reapproximation by approximately 5mm. This paper supports the early use of maximal equinus casting in early management of acute Achilles tendon ruptures. Copyright © 2017 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

Peroneal tendon disorders.

PubMed

Davda, Kinner; Malhotra, Karan; O'Donnell, Paul; Singh, Dishan; Cullen, Nicholas

2017-06-01

Pathological abnormality of the peroneal tendons is an under-appreciated source of lateral hindfoot pain and dysfunction that can be difficult to distinguish from lateral ankle ligament injuries.Enclosed within the lateral compartment of the leg, the peroneal tendons are the primary evertors of the foot and function as lateral ankle stabilisers.Pathology of the tendons falls into three broad categories: tendinitis and tenosynovitis, tendon subluxation and dislocation, and tendon splits and tears. These can be associated with ankle instability, hindfoot deformity and anomalous anatomy such as a low lying peroneus brevis or peroneus quartus.A thorough clinical examination should include an assessment of foot type (cavus or planovalgus), palpation of the peronei in the retromalleolar groove on resisted ankle dorsiflexion and eversion as well as testing of lateral ankle ligaments.Imaging including radiographs, ultrasound and MRI will help determine the diagnosis. Treatment recommendations for these disorders are primarily based on case series and expert opinion.The aim of this review is to summarise the current understanding of the anatomy and diagnostic evaluation of the peroneal tendons, and to present both conservative and operative management options of peroneal tendon lesions. Cite this article: EFORT Open Rev 2017;2:281-292. DOI: 10.1302/2058-5241.2.160047.

The effect of muscle excursion on muscle recovery after tendon repair in a neglected tendon injury: a study in rabbit soleus muscles.

PubMed

Jeon, Suk Ha; Chung, Moon Sang; Baek, Goo Hyun; Lee, Young Ho; Gong, Hyun Sik

2011-01-01

We attempted to determine whether muscle excursion observed during operation can be a prognostic indicator of muscle recovery after delayed tendon repair in a rabbit soleus model. Eighteen rabbits underwent tenotomy of the soleus muscles bilaterally and were divided into three groups according to the period from tenotomy to repair. The tendons of each group were repaired 2, 4, and 6 weeks after tenotomy. The excursion of each soleus muscle was measured at the time of tenotomy (baseline), at 2, 4, 6 weeks after tenotomy, and 8 weeks after tendon repair. The amount of muscle recovery after tendon repair in terms of muscle excursion independently depended on the timing of repair and on the muscle excursion observed during repair. The regression model predicted that the muscle excursion recovered on average by 0.6% as the muscle excursion at the time of repair increased by 1% after adjusting for the timing of repair. This study suggests that measuring the muscle excursion during tendon repair may help physicians estimate the potential of muscle recovery in cases of delayed tendon repair. Copyright © 2010 Orthopaedic Research Society.

Moderate treadmill running exercise prior to tendon injury enhances wound healing in aging rats.

PubMed

Zhang, Jianying; Yuan, Ting; Wang, James H-C

2016-02-23

The effect of exercise on wound healing in aging tendon was tested using a rat moderate treadmill running (MTR) model. The rats were divided into an MTR group that ran on a treadmill for 4 weeks and a control group that remained in cages. After MTR, a window defect was created in the patellar tendons of all rats and wound healing was analyzed. We found that MTR accelerated wound healing by promoting quicker closure of wounds, improving the organization of collagen fibers, and decreasing senescent cells in the wounded tendons when compared to the cage control. MTR also lowered vascularization, increased the numbers of tendon stem/progenitor cells (TSCs) and TSC proliferation than the control. Besides, MTR significantly increased the expression of stem cell markers, OCT-4 and Nanog, and tenocyte genes, Collagen I, Collagen III and tenomodulin, and down-regulated PPAR-γ, Collagen II and Runx-2 (non-tenocyte genes). These findings indicated that moderate exercise enhances healing of injuries in aging tendons through TSC based mechanisms, through which exercise regulates beneficial effects in tendons. This study reveals that appropriate exercise may be used in clinics to enhance tendon healing in aging patients.

Functional management of Achilles tendon rupture: A viable option for non-operative management.

PubMed

Karkhanis, S; Mumtaz, H; Kurdy, N

2010-06-01

Functional management of the ruptured Achilles tendon can be effective using orthoses like the removable walker boot (Foam Walker Boot, Air Cast UK Limited, Lincolnshire, United Kingdom). We conducted this study to look at the outcome of our protocol using this orthosis. We retrospectively reviewed 107 non-operatively managed Achilles tendon ruptures over the last 5 years. Case notes were analyzed for demographics and immediate outcomes. Long term outcomes were assessed by a postal questionnaire using the Achilles Tendon Total Rupture Score (ATRS). Of the 107 tendons (male:female=71:36, mean age=50 years), 105 tendons (98%) healed with an average discharge time of 22 weeks. Six patients reported major complications and 6 reported minor complications. We received 56 questionnaires with a mean ATRS score of 21. Seventy-seven percent returned to pre-injury level of activity. Functional management of Achilles tendon rupture, under appropriate supervision, provides a viable option for non-operative management. Copyright 2009 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

Acute flexor tendon injury following midshaft radius and ulna fractures in a paediatric patient.

PubMed

Williams, James; Wharton, Rupert; Peev, Peter; Horwitz, Maxim

2018-06-01

Delayed rupture of the extensor and flexor tendons are recognised complications of distal radius fractures. However, acute flexor tendon rupture in the context of forearm fractures is rare. A twelve-year-old female sustained midshaft fractures of the radius and ulna. Intra-operatively the flexor pollicis longus (FPL) was found to be stripped from its musculotendinous junction at the level of the fracture fragment. The ruptured tendon was repaired using a modified Krackow technique at the time of fracture fixation. The repair was protected in plaster of Paris prior to referral to the paediatric hand clinic. The patient made a full recovery. Flexor tendon injury is a rare but potentially devastating consequence of acute forearm fractures. High energy trauma, significant volar angulation of the fracture fragment and clinical signs of flexor tendon injury should raise suspicion of this injury. A high index of suspicion in conjunction with repeat clinical examination of flexor tendon function should be performed before opting for closed management or intramedullary nailing in paediatric patients.

Radial and ulnar bursae of the wrist: cadaveric investigation of regional anatomy with ultrasonographic-guided tenography and MR imaging.

PubMed

Aguiar, Rodrigo O C; Gasparetto, Emerson L; Escuissato, Dante L; Marchiori, Edson; Trudell, Debbie J; Haghighi, Parviz; Resnick, Donald

2006-11-01

To demonstrate the anatomy of the radial and ulnar bursae of the wrist using MR and US images. Ultrasonographic-guided tenography of the tendon sheath of flexor pollicis longus (FPL) and the common tendon sheath of the flexor digitorum of the fifth digit (FD5) of ten cadaveric hands was performed, followed by magnetic resonance imaging and gross anatomic correlation. Patterns of communication were observed between these tendon sheaths and the radial and ulnar bursae of the wrist. The tendon sheath of the FPL communicated with the radial bursa in 100% (10/10) of cases, and the tendon sheath of the FD5 communicated with the ulnar bursa in 80% (8/10). Communication of the radial and ulnar bursae was evident in 100% (10/10), and presented an "hourglass" configuration in the longitudinal plane. The ulnar and radial bursae often communicate. The radial bursa communicates with the FPL tendon sheath, and the ulnar bursa may communicate with the FD5 tendon sheath.

Extracorporeal shock wave treatment for chronic rotator cuff tendonitis (shoulder pain).

PubMed

Ho, C

2007-01-01

(1) Electrohydraulic, electromagnetic, or piezoelectric devices are used to translate energy into acoustic waves during extracorporeal shock wave treatment (ESWT) for chronic rotator cuff tendonitis (shoulder pain). The acoustic waves may help to accelerate the healing process of chronic rotator cuff tendonitis via an unknown mechanism. (2) ESWT, which is performed as an outpatient procedure, is intended to alleviate the pain due to chronic rotator cuff tendonitis. (3) Limited evidence from a German study indicates that the cost of ESWT for rotator cuff tendonitis is one-fifth to one-seventh the cost of surgical treatment, with longer recovery time and time off work in the surgical treatment group accounting for about two-thirds of the overall cost. (4) The evidence reviewed for this bulletin supports the use of high-energy ESWT for chronic calcific rotator cuff tendonitis, but not for non-calcific rotator cuff tendonitis. High-quality RCTs with larger sample sizes are needed to provide stronger evidence.

System and Method for Tensioning a Robotically Actuated Tendon

NASA Technical Reports Server (NTRS)

Reiland, Matthew J. (Inventor); Diftler, Myron A. (Inventor)

2013-01-01

A tendon tensioning system includes a tendon having a proximal end and a distal end, an actuator, and a motor controller. The actuator may include a drive screw and a motor, and may be coupled with the proximal end of the tendon and configured to apply a tension through the tendon in response to an electrical current. The motor controller may be electrically coupled with the actuator, and configured to provide an electrical current having a first amplitude to the actuator until a stall tension is achieved through the tendon; provide a pulse current to the actuator following the achievement of the stall tension, where the amplitude of the pulse current is greater than the first amplitude, and return the motor to a steady state holding current following the conclusion of the pulse current.

Torque Control of Underactuated Tendon-driven Robotic Fingers

NASA Technical Reports Server (NTRS)

Ihrke, Chris A. (Inventor); Wampler, Charles W. (Inventor); Abdallah, Muhammad E. (Inventor); Reiland, Matthew J. (Inventor); Diftler, Myron A. (Inventor); Bridgwater, Lyndon (Inventor); Platt, Robert (Inventor)

2013-01-01

A robotic system includes a robot having a total number of degrees of freedom (DOF) equal to at least n, an underactuated tendon-driven finger driven by n tendons and n DOF, the finger having at least two joints, being characterized by an asymmetrical joint radius in one embodiment. A controller is in communication with the robot, and controls actuation of the tendon-driven finger using force control. Operating the finger with force control on the tendons, rather than position control, eliminates the unconstrained slack-space that would have otherwise existed. The controller may utilize the asymmetrical joint radii to independently command joint torques. A method of controlling the finger includes commanding either independent or parameterized joint torques to the controller to actuate the fingers via force control on the tendons.

Endoscopic-assisted Repair of Neglected Rupture or Rerupture After Primary Repair of Extensor Hallucis Longus Tendon.

PubMed

Lui, Tun Hing; Chang, Joseph Jeremy; Maffulli, Nicola

2016-03-01

Rerupture of the extensor hallucis longus tendon after primary repair and neglected rupture of the tendon poses surgical challenges to orthopedic surgeons. Open exploration and repair of the tendon ends usually requires large incision and extensive dissection. This may induce scarring and adhesion around the repaired tendon. Endoscopic-assisted repair has the advantage of minimally invasive surgery including less soft tissue trauma and scar formation and better cosmetic result. The use of Krackow locking suture and preservation of the extensor retinacula allow early mobilization of the great toe.

Treatment of the neglected Achilles tendon rupture.

PubMed

Bevilacqua, Nicholas J

2012-04-01

Achilles tendon ruptures are best managed acutely. Neglected Achilles tendon ruptures are debilitating injuries and the increased complexity of the situation must be appreciated. Surgical management is recommended, and only in the poorest surgical candidate is conservative treatment entertained. Numerous treatment algorithms and surgical techniques have been described. A V-Y advancement flap and flexor halluces longus tendon transfer have been found to be reliable and achieve good clinical outcomes for defects ranging from 2 cm to 8 cm. This article focuses on the treatment options for the neglected Achilles tendon rupture. Copyright © 2012 Elsevier Inc. All rights reserved.

Tendon Contraction After Cyclic Elongation Is an Age-Dependent Phenomenon: In Vitro and In Vivo Comparisons.

PubMed

Lavagnino, Michael; Bedi, Asheesh; Walsh, Christopher P; Sibilsky Enselman, Elizabeth R; Sheibani-Rad, Shahin; Arnoczky, Steven P

2014-06-01

Tendons are viscoelastic tissues that deform (elongate) in response to cyclic loading. However, the ability of a tendon to recover this elongation is unknown. Tendon length significantly increases after in vivo or in vitro cyclic loading, and the ability to return to its original length through a cell-mediated contraction mechanism is an age-dependent phenomenon. Controlled laboratory study. In vitro, rat tail tendon fascicles (RTTfs) from Sprague-Dawley rats of 3 age groups (1, 3, and 12 months) underwent 2% cyclic strain at 0.17 Hz for 2 hours, and the percentages of elongation were determined. After loading, the RTTfs were suspended for 3 days under tissue culture conditions and photographed daily to determine the amount of length contraction. In vivo, healthy male participants (n = 29; age, 19-49 years) had lateral, single-legged weightbearing radiographs taken of the knee at 60° of flexion immediately before, immediately after, and 24 hours after completing eccentric quadriceps loading exercises on the dominant leg to fatigue. Measurements of patellar tendon length were taken from the radiographs, and the percentages of tendon elongation and subsequent contraction were calculated. In vitro, cyclic loading increased the length of all RTTfs, with specimens from younger (1 and 3 months) rats demonstrating significantly greater elongation than those from older (12 months) rats (P = .009). The RTTfs contracted to their original length significantly faster (P < .001) and in an age-dependent fashion, with younger animals contracting faster. In vivo, repetitive eccentric loading exercises significantly increased patellar tendon length (P < .001). Patellar tendon length decreased 24 hours after exercises (P < .001) but did not recover completely (P < .001). There was a weak but significant (R (2) = 0.203, P = .014) linear correlation between the amount of tendon contraction and age, with younger participants (<30 years) demonstrating significantly more contraction (P = .014) at 24 hours than older participants (>30 years). Cyclic tendon loading results in a significant increase in tendon elongation under both in vitro and in vivo conditions. Tendons in both conditions demonstrated an incomplete return to their original length after 24 hours, and the extent of this return was age dependent. The age- and time-dependent contraction of tendons, elongated after repetitive loading, could result in transient alterations in the mechanobiological environment of tendon cells. This, in turn, could induce the onset of catabolic changes associated with the pathogenesis of tendinopathy. These results suggest the importance of allowing time for contraction between bouts of repetitive exercise and may explain why age is a predisposing factor in tendinopathy. © 2014 The Author(s).

The effect of platelet-rich fibrin matrix on rotator cuff tendon healing: a prospective, randomized clinical study.

PubMed

Rodeo, Scott A; Delos, Demetris; Williams, Riley J; Adler, Ronald S; Pearle, Andrew; Warren, Russell F

2012-06-01

There is a strong need for methods to improve the biological potential of rotator cuff tendon healing. Platelet-rich fibrin matrix (PRFM) allows delivery of autologous cytokines to healing tissue, and limited evidence suggests a positive effect of platelet-rich plasma on tendon biology. To evaluate the effect of platelet-rich fibrin matrix on rotator cuff tendon healing. Randomized controlled trial; Level of evidence, 2. Seventy-nine patients undergoing arthroscopic rotator cuff tendon repair were randomized intraoperatively to either receive PRFM at the tendon-bone interface (n = 40) or standard repair with no PRFM (n = 39). Standardized repair techniques were used for all patients. The postoperative rehabilitation protocol was the same in both groups. The primary outcome was tendon healing evaluated by ultrasound (intact vs defect at repair site) at 6 and 12 weeks. Power Doppler ultrasound was also used to evaluate vascularity in the peribursal, peritendinous, and musculotendinous and insertion site areas of the tendon and bone anchor site. Secondary outcomes included standardized shoulder outcome scales (American Shoulder and Elbow Surgeons [ASES] and L'Insalata) and strength measurements using a handheld dynamometer. Patients and the evaluator were blinded to treatment group. All patients were evaluated at minimum 1-year follow-up. A logistic regression model was used to predict outcome (healed vs defect) based on tear severity, repair type, treatment type (PRFM or control), and platelet count. Overall, there were no differences in tendon-to-bone healing between the PRFM and control groups. Complete tendon-to-bone healing (intact repair) was found in 24 of 36 (67%) in the PRFM group and 25 of 31 (81%) in the control group (P = .20). There were no significant differences in healing by ultrasound between 6 and 12 weeks. There were gradual increases in ASES and L'Insalata scores over time in both groups, but there were no differences in scores between the groups. We also found no difference in vascularity in the peribursal, peritendinous, and musculotendinous areas of the tendon between groups. There were no differences in strength between groups. Platelet count had no effect on healing. Logistic regression analysis demonstrated that PRFM was a significant predictor (P = .037) for a tendon defect at 12 weeks, with an odds ratio of 5.8. Platelet-rich fibrin matrix applied to the tendon-bone interface at the time of rotator cuff repair had no demonstrable effect on tendon healing, tendon vascularity, manual muscle strength, or clinical rating scales. In fact, the regression analysis suggests that PRFM may have a negative effect on healing. Further study is required to evaluate the role of PRFM in rotator cuff repair.

Effect of the Interposition of Calcium Phosphate Materials on Tendon-Bone Healing During Repair of Chronic Rotator Cuff Tear.

PubMed

Zhao, Song; Peng, Lingjie; Xie, Guoming; Li, Dingfeng; Zhao, Jinzhong; Ning, Congqin

2014-08-01

The current nature of tendon-bone healing after rotator cuff (RC) repair is still the formation of granulation tissue at the tendon-bone interface rather than the formation of fibrocartilage, which is the crucial structure in native tendon insertion and can be observed after knee ligament reconstruction. The interposition of calcium phosphate materials has been found to be able to enhance tendon-bone healing in knee ligament reconstruction. However, whether the interposition of these kinds of materials can enhance tendon-bone healing or even change the current nature of tendon-bone healing after RC repair still needs to be explored. The interposition of calcium phosphate materials during RC repair would enhance tendon-bone healing or change its current nature of granulation tissue formation into a more favorable process. Controlled laboratory study. A total of 144 male Sprague-Dawley rats underwent unilateral detachment of the supraspinatus tendon, followed by delayed repair after 3 weeks. The animals were allocated into 1 of 3 groups: (1) repair alone, (2) repair with Ca5(PO4)2SiO4 (CPS) bioceramic interposition, or (3) repair with hydroxyapatite (HA) bioceramic interposition at the tendon-bone interface. Animals were sacrificed at 2, 4, or 8 weeks postoperatively, and microcomputed tomography (micro-CT) was used to quantify the new bone formation at the repair site. New fibrocartilage formation and collagen organization at the tendon-bone interface was evaluated by histomorphometric analysis. Biomechanical testing of the supraspinatus tendon-bone complex was performed. Statistical analysis was performed using 1-way analysis of variance. Significance was set at P < .05. The micro-CT analysis demonstrated remarkable osteogenic activity and osteoconductivity to promote new bone formation and ingrowth of CPS and HA bioceramic, with CPS bioceramic showing better results than HA. Histological observations indicated that CPS bioceramic had excellent biocompatibility and biodegradability. At early time points after the RC repair, CPS bioceramic significantly increased the area of fibrocartilage at the tendon-bone interface compared with the control and HA groups. Moreover, CPS and HA bioceramics had significantly improved collagen organization. Biomechanical tests indicated that the CPS and HA groups have greater ultimate load to failure and stiffness than the control group at 4 and 8 weeks, and the CPS specimens exhibited the maximum ultimate load to failure, stiffness, and stress of the healing enthesis. Both CPS and HA bioceramics aid in cell attachment and proliferation and accelerate new bone formation, and CPS bioceramic has a more prominent effect on tendon-to-bone healing. Local application of CPS and HA bioceramic at the tendon-bone interface shows promise in improving healing after rotator cuff tear repair. © 2014 The Author(s).

Living nanofiber yarn-based woven biotextiles for tendon tissue engineering using cell tri-culture and mechanical stimulation.

PubMed

Wu, Shaohua; Wang, Ying; Streubel, Philipp N; Duan, Bin

2017-10-15

Non-woven nanofibrous scaffolds have been developed for tendon graft application by using electrospinning strategies. However, electrospun nanofibrous scaffolds face some obstacles and limitations, including suboptimal scaffold structure, weak tensile and suture-retention strengths, and compact structure for cell infiltration. In this work, a novel nanofibrous, woven biotextile, fabricated based on electrospun nanofiber yarns, was implemented as a tissue engineered tendon scaffold. Based on our modified electrospinning setup, polycaprolactone (PCL) nanofiber yarns were fabricated with reproducible quality, and were further processed into plain-weaving fabrics interlaced with polylactic acid (PLA) multifilaments. Nonwoven nanofibrous PCL meshes with random or aligned fiber structures were generated using typical electrospinning as comparative counterparts. The woven fabrics contained 3D aligned microstructures with significantly larger pore size and obviously enhanced tensile mechanical properties than their nonwoven counterparts. The biological results revealed that cell proliferation and infiltration, along with the expression of tendon-specific genes by human adipose derived mesenchymal stem cells (HADMSC) and human tenocytes (HT), were significantly enhanced on the woven fabrics compared with those on randomly-oriented or aligned nanofiber meshes. Co-cultures of HADMSC with HT or human umbilical vein endothelial cells (HUVEC) on woven fabrics significantly upregulated the functional expression of most tenogenic markers. HADMSC/HT/HUVEC tri-culture on woven fabrics showed the highest upregulation of most tendon-associated markers than all the other mono- and co-culture groups. Furthermore, we conditioned the tri-cultured constructs with dynamic conditioning and demonstrated that dynamic stretch promoted total collagen secretion and tenogenic differentiation. Our nanofiber yarn-based biotextiles have significant potential to be used as engineered scaffolds to synergize the multiple cell interaction and mechanical stimulation for promoting tendon regeneration. Tendon grafts are essential for the treatment of various tendon-related conditions due to the inherently poor healing capacity of native tendon tissues. In this study, we combined electrospun nanofiber yarns with textile manufacturing strategies to fabricate nanofibrous woven biotextiles with hierarchical features, aligned fibrous topography, and sufficient mechanical properties as tendon tissue engineered scaffolds. Comparing to traditional electrospun random or aligned meshes, our novel nanofibrous woven fabrics possess strong tensile and suture-retention strengths and larger pore size. We also demonstrated that the incorporation of tendon cells and vascular cells promoted the tenogenic differentiation of the engineered tendon constructs, especially under dynamic stretch. This study not only presents a novel tissue engineered tendon scaffold fabrication technique but also provides a useful strategy to promote tendon differentiation and regeneration. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

The effect of a collagen-elastin matrix on adhesion formation after flexor tendon repair in a rabbit model.

PubMed

Wichelhaus, Dagmar Alice; Beyersdoerfer, Sascha Tobias; Gierer, Philip; Vollmar, Brigitte; Mittlmeier, Th

2016-07-01

The outcome of flexor tendon surgery is negatively affected by the formation of adhesions which can occur during the healing of the tendon repair. In this experimental study, we sought to prevent adhesion formation by wrapping a collagen-elastin scaffold around the repaired tendon segment. In 28 rabbit hind legs, the flexor tendons of the third and fourth digits were cut and then repaired using a two-strand suture technique on the fourth digit and a four-strand technique on the third digit. Rabbits were randomly assigned to study and control groups. In the control group, the operation ended by closing the tendon sheath and the skin. In the study group, a collagen-elastin scaffold was wrapped around the repaired tendon segment in both digits. After 3 and 8 weeks, the tendons were harvested and processed histologically. The range of motion of the digits and the gap formation between the repaired tendon ends were measured. The formation of adhesions, infiltration of leucocytes and extracellular inflammatory response were quantified. At the time of tendon harvesting, all joints of the operated toes showed free range of motion. Four-strand core sutures lead to significantly less diastasis between the repaired tendon ends than two-strand core suture repairs. The collagen-elastin scaffold leads to greater gapping after 3 weeks compared to the controls treated without the matrix. Within the tendons treated with the collagen-elastin matrix, a significant boost of cellular and extracellular inflammation could be stated after 3 weeks which was reflected by a higher level of CAE positive cells and more formation of myofibroblasts in the αSMA stain in the study group. The inflammatory response subsided gradually and significantly until the late stage of the study. Both the cellular and extracellular inflammatory response was emphasized with the amount of material used for the repair. The use of a collagen-elastin matrix cannot be advised for the prevention of adhesion formation in flexor tendon surgery, because it enhances both cellular and extracellular inflammation. Four-strand core sutures lead to less gapping than two-strand core sutures, but at the same time, the cellular and extracellular inflammatory response is more pronounced.

Cellular and molecular maturation in fetal and adult ovine calcaneal tendons

PubMed Central

Russo, Valentina; Mauro, Annunziata; Martelli, Alessandra; Di Giacinto, Oriana; Di Marcantonio, Lisa; Nardinocchi, Delia; Berardinelli, Paolo; Barboni, Barbara

2015-01-01

Processes of development during fetal life profoundly transform tendons from a plastic tissue into a highly differentiated structure, characterised by a very low ability to regenerate after injury in adulthood. Sheep tendon is frequently used as a translational model to investigate cell-based regenerative approaches. However, in contrast to other species, analytical and comparative baseline studies on the normal developmental maturation of sheep tendons from fetal through to adult life are not currently available. Thus, a detailed morphological and biochemical study was designed to characterise tissue maturation during mid- (2 months of pregnancy: 14 cm of length) and late fetal (4 months: 40 cm of length) life, through to adulthood. The results confirm that ovine tendon morphology undergoes profound transformations during this period. Endotenon was more developed in fetal tendons than in adult tissues, and its cell phenotype changed through tendon maturation. Indeed, groups of large rounded cells laying on smaller and more compacted ones expressing osteocalcin, vascular endothelial growth factor (VEGF) and nerve growth factor (NGF) were identified exclusively in fetal mid-stage tissues, and not in late fetal or adult tendons. VEGF, NGF as well as blood vessels and nerve fibers showed decreased expression during tendon development. Moreover, the endotenon of mid- and late fetuses contained identifiable cells that expressed several pluripotent stem cell markers [Telomerase Reverse Transcriptase (TERT), SRY Determining Region Y Box-2 (SOX2), Nanog Homeobox (NANOG) and Octamer Binding Transcription Factor-4A (OCT-4A)]. These cells were not identifiable in adult specimens. Ovine tendon development was also accompanied by morphological modifications to cell nuclei, and a progressive decrease in cellularity, proliferation index and expression of connexins 43 and 32. Tendon maturation was similarly characterised by modulation of several other gene expression profiles, including Collagen type I, Collagen type III, Scleraxis B, Tenomodulin, Trombospondin 4 and Osteocalcin. These gene profiles underwent a dramatic reduction in adult tissues. Transforming growth factor-1 expression (involved in collagen synthesis) underwent a similar decrease. In conclusion, these morphological studies carried out on sheep tendons at different stages of development and aging offer normal structural and molecular baseline data to allow accurate evaluation of data from subsequent interventional studies investigating tendon healing and regeneration in ovine experimental models. PMID:25546075

Ruptured Tendons in Anabolic-Androgenic Steroid Users: A Cross-Sectional Cohort Study

PubMed Central

Kanayama, Gen; DeLuca, James; Meehan, William P.; Hudson, James I.; Isaacs, Stephanie; Baggish, Aaron; Weiner, Rory; Micheli, Lyle; Pope, Harrison G.

2016-01-01

Background Accumulating case reports have described tendon rupture in men using anabolic-androgenic steroids (AAS). However no controlled study, to our knowledge, has assessed history of tendon rupture in a large cohort of AAS users and comparison nonusers. Hypothesis We hypothesized that men reporting long-term AAS abuse would report an elevated lifetime incidence of tendon rupture as compared to non-AAS-using bodybuilders. Study Design Cross-sectional cohort study. Methods We obtained medical histories from 142 experienced male bodybuilders age 35–55, recruited in the course of two studies. Of these men, 88 reported at least two years of cumulative lifetime AAS use and 54 reported no history of AAS use. In men reporting a history of tendon rupture, we recorded circumstances of the injury, prodromal symptoms, concomitant drug or alcohol use, and details of current and lifetime AAS use if applicable. We also obtained surgical records for most participants. Results Nineteen (22%) of the AAS users, but only 3 (6%) of the nonusers reported at least one lifetime tendon rupture. The hazard ratio (95% confidence interval) for a first ruptured tendon in AAS users versus nonusers was 9.0 (2.5, 32.3); P <.001. Several men reported two or more independent lifetime tendon ruptures. Interestingly, upper body tendon ruptures occurred exclusively in the AAS group (15 [17%] of the AAS users versus 0 non-users; risk difference 0.17 (0.09, 0.25); P < 0.001 [hazard ratio not estimable]), whereas we found no significant difference between users and nonusers in risk for lower body ruptures (6 [7%] AAS users, 3 [6%] nonusers; hazard ratio 3.1 (0.7, 13.8), P = 0.13). Of 31 individual tendon ruptures that we assessed, only 6 (19%) occurred while weightlifting, with the majority occurring during other sports activities. Eight (26%) ruptures followed prodromal symptoms of nonspecific pain in the region. Virtually all ruptures were treated surgically with complete or near-complete ultimate restoration of function. Conclusions AAS abusers, as compared to otherwise similar bodybuilders, showed a markedly increased risk of tendon ruptures, particularly upper body tendon rupture. Clinical relevance Tendon rupture represents a major adverse consequence of AAS abuse and a substantial public health problem. PMID:26362436

Ultrasonographic investigation of the Achilles tendon in elite badminton players using color Doppler.

PubMed

Boesen, Morten Ilum; Boesen, Anders; Koenig, Merete Juhl; Bliddal, Henning; Torp-Pedersen, Soren

2006-12-01

The most frequent injuries in badminton players are in the lower extremities, especially in the Achilles tendon. The game of badminton may be related to abnormal intratendinous flow in the Achilles tendon as detected by color Doppler ultrasound. To a certain extent, this blood flow might be physiological, especially when examined after match. Cohort study (prevalence); Level of evidence, 3. Seventy-two elite badminton players were interviewed regarding Achilles tendon pain (achillodynia) in the preceding 3 years. Color Doppler was used to examine the tendons of 64 players before their matches and 46 players after their matches. Intratendinous color Doppler flow was graded from 0 to 4. The Achilles tendon was divided into dominant (eg, right side for right-handed players and vice versa) and nondominant side and classified as midtendon, preinsertional, and calcaneal areas. Of 72 players, 26 had experienced achillodynia in 34 tendons, 18 on the dominant side and 16 on the nondominant side. In 62% of the players with achillodynia, the problems had begun slowly, and the median duration of symptoms was 4 months (range, 0-36 months). Thirty-five percent had ongoing pain in their tendons for a median duration of 12 months (range, 0-12 months). Achillodynia was not associated with the self-reported training load or with sex, age, weight, singles or doubles players, or racket side. Forty-six players were scanned before and after match. At baseline, color Doppler flow was present in the majority of players, and only 7 (16%) players had no color Doppler flow in either tendon. After match, all players had some color Doppler flow in 1 or both tendons. Achillodynia and color Doppler flow were related in the nondominant Achilles tendon (chi-square, P = .008). The grades of Doppler flow also increased significantly after match in the preinsertional area in both the nondominant (P = .0002) and dominant (P = .005) side tendons. A large proportion of the players had experienced achillodynia and habitually played with a degree of pain that demanded medication. The self-reported pain was associated with increased intratendinous color Doppler flow in the nondominant Achilles tendon. Doppler flow was found in most players before and in all players after the match and therefore may in part be a physiological response to activity.

Effect of Age and Proteoglycan Deficiency on Collagen Fiber Re-Alignment and Mechanical Properties in Mouse Supraspinatus Tendon

PubMed Central

Connizzo, Brianne K.; Sarver, Joseph J.; Iozzo, Renato V.; Birk, David E.; Soslowsky, Louis J.

2013-01-01

Collagen fiber realignment is one mechanism by which tendon responds to load. Re-alignment is altered when the structure of tendon is altered, such as in the natural process of aging or with alterations of matrix proteins, such as proteoglycan expression. While changes in re-alignment and mechanical properties have been investigated recently during development, they have not been studied in (1) aged tendons, or (2) in the absence of key proteoglycans. Collagen fiber re-alignment and the corresponding mechanical properties are quantified throughout tensile mechanical testing in both the insertion site and the midsubstance of mouse supraspinatus tendons in wild type (WT), decorin-null (Dcn-/-), and biglycan-null (Bgn-/-) mice at three different ages (90 days, 300 days, and 570 days). Percent relaxation was significantly decreased with age in the WT and Dcn-/- tendons, but not in the Bgn-/- tendons. Changes with age were found in the linear modulus at the insertion site where the 300 day group was greater than the 90 day and 570 day group in the Bgn-/- tendons and the 90 day group was smaller than the 300 day and 570 day groups in the Dcn-/- tendons. However, no changes in modulus were found across age in WT tendons were found. The midsubstance fibers of the WT and Bgn-/- tendons were initially less aligned with increasing age. The re-alignment was significantly altered with age in the WT tendons, with older groups responding to load later in the mechanical test. This was also seen in the Dcn-/- midsubstance and the Bgn-/- insertion, but not in the other locations. Although some studies have found changes in the WT mechanical properties with age, this study did not support those findings. However, it did show fiber re-alignment changes at both locations with age, suggesting a breakdown of tendon′s ability to respond to load in later ages. In the proteoglycan-null tendons however, there were changes in the mechanical properties, accompanied only by location-dependent re-alignment changes, suggesting a site-specific role for these molecules in loading. Finally, changes in the mechanical properties did not occur in concert with changes in re-alignment, suggesting that typical mechanical property measurements alone are insufficient to describe how structural alterations affect tendon′s response to load. PMID:23445064

Macroscopic Rotator Cuff Tendinopathy and Histopathology Do Not Predict Repair Outcomes of Rotator Cuff Tears.

PubMed

Sethi, Paul M; Sheth, Chirag D; Pauzenberger, Leo; McCarthy, Mary Beth R; Cote, Mark P; Soneson, Emma; Miller, Seth; Mazzocca, Augustus D

2018-03-01

Numerous studies have identified factors that may affect the chances of rotator cuff healing after surgery. Intraoperative tendon quality may be used to predict healing and to determine type of repair and/or consideration of augmentation. There are no data that correlate how gross tendon morphology and degree of tendinopathy affect patient outcome or postoperative tendon healing. Purpose/Hypothesis: The purposes of this study were to (1) compare the gross appearance of the tendon edge during arthroscopic rotator cuff repair with its histological degree of tendinopathy and (2) determine if gross appearance correlated with postoperative repair integrity. The hypothesis was that gross (macroscopic) tendon with normal thickness, no delamination, and elastic tissue before repair would have a correlation with low Bonar scores, higher postoperative American Shoulder and Elbow Surgeons (ASES) scores, and increased rates of postoperative tendon healing on ultrasound. Cross-sectional study; Level of evidence, 3. A total of 105 patients undergoing repair of medium-size (1-3 cm) full-thickness rotator cuff tears were enrolled in the study. Intraoperatively, the supraspinatus tendon was rated on thickness, fraying, and stiffness. Tendon tissue was recovered for histological analysis based on the Bonar scoring system. Postoperative ASES and ultrasound assessment of healing were obtained 1 year after repair. Correlation between gross appearance of the tendon and rotator cuff histology was determined. Of the 105 patients, 85 were followed the study to completion. The mean age of the patients was 61.6 years; Bonar score, 7.5; preoperative ASES score, 49; and postoperative ASES score, 86. Ninety-one percent of repairs were intact on ultrasound. Gross appearance of torn rotator cuff tendon tissue did not correlate with histological appearance. Neither histological (Bonar) score nor gross appearance correlated with multivariate analysis of ASES score, postoperative repair status, or demographic data. The degree of tendinopathy did not correlate with morphological appearance of the tendon. Neither of these parameters correlated with healing or patient outcome. This study suggests that the degree of tendinopathy, unlike muscle atrophy, may not be predictive of outcomes and that, on appearance, poor quality tendon has adequate healing capacity. Therefore, abnormal gross tendon appearance should not affect the repair effort or technique.

Fetal derived embryonic-like stem cells improve healing in a large animal flexor tendonitis model

PubMed Central

2011-01-01

Introduction Tendon injury is a common problem in athletes, with poor tissue regeneration and a high rate of re-injury. Stem cell therapy is an attractive treatment modality as it may induce tissue regeneration rather than tissue repair. Currently, there are no reports on the use of pluripotent cells in a large animal tendon model in vivo. We report the use of intra-lesional injection of male, fetal derived embryonic-like stem cells (fdESC) that express Oct-4, Nanog, SSEA4, Tra 1-60, Tra 1-81 and telomerase. Methods Tendon injury was induced using a collagenase gel-physical defect model in the mid-metacarpal region of the superficial digital flexor tendon (SDFT) of eight female adult Thoroughbred or Thoroughbred cross horses. Tendon lesions were treated one week later with intra-lesional injection of male derived fdESCs in media or media alone. Therapy was blinded and randomized. Serial ultrasound examinations were performed and final analysis at eight weeks included magnetic resonance imaging (MRI), biochemical assays (total DNA, glycosaminoglycan, collagen), gene expression (TNC, TNMD, SCX, COL1A1, COL3A1, COMP, DCN, MMP1, MMP3, MMP13, 18S) and histology. Differences between groups were assessed with Wilcoxon's rank sum test. Results Cell survival was demonstrated via the presence of the SRY gene in fdESC treated, but not control treated, female SDFT at the end of the trial. There were no differences in tendon matrix specific gene expression or total proteoglycan, collagen or DNA of tendon lesions between groups. Tissue architecture, tendon size, tendon lesion size, and tendon linear fiber pattern were significantly improved on histologic sections and ultrasound in the fdESC treated tendons. Conclusions Such profound structural effects lend further support to the notion that pluripotent stem cells can effect musculoskeletal regeneration, rather than repair, even without in vitro lineage specific differentiation. Further investigation into the safety of pluripotent cellular therapy as well as the mechanisms by which repair was improved seem warranted. PMID:21272343

Ruptured Tendons in Anabolic-Androgenic Steroid Users: A Cross-Sectional Cohort Study.

PubMed

Kanayama, Gen; DeLuca, James; Meehan, William P; Hudson, James I; Isaacs, Stephanie; Baggish, Aaron; Weiner, Rory; Micheli, Lyle; Pope, Harrison G

2015-11-01

Accumulating case reports have described tendon rupture in men who use anabolic-androgenic steroids (AAS). However, no controlled study has assessed the history of tendon rupture in a large cohort of AAS users and comparison nonusers. Men reporting long-term AAS abuse would report an elevated lifetime incidence of tendon rupture compared with non-AAS-using bodybuilders. Cohort study; Level of evidence, 3. Medical histories were obtained from 142 experienced male bodybuilders aged 35 to 55 years recruited in the course of 2 studies. Of these men, 88 reported at least 2 years of cumulative lifetime AAS use, and 54 reported no history of AAS use. In men reporting a history of tendon rupture, the circumstances of the injury, prodromal symptoms, concomitant drug or alcohol use, and details of current and lifetime AAS use (if applicable) were recorded. Surgical records were obtained for most participants. Nineteen (22%) of the AAS users, but only 3 (6%) of the nonusers, reported at least 1 lifetime tendon rupture. The hazard ratio for a first ruptured tendon in AAS users versus nonusers was 9.0 (95% CI, 2.5-32.3; P < .001). Several men reported 2 or more independent lifetime tendon ruptures. Interestingly, upper-body tendon ruptures occurred exclusively in the AAS group (15 [17%] AAS users vs 0 nonusers; risk difference, 0.17 [95% CI, 0.09-0.25]; P < .001 [hazard ratio not estimable]), whereas there was no significant difference between users and nonusers in risk for lower-body ruptures (6 [7%] AAS users, 3 [6%] nonusers; hazard ratio, 3.1 [95% CI, 0.7-13.8]; P = .13). Of 31 individual tendon ruptures assessed, only 6 (19%) occurred while weightlifting, with the majority occurring during other sports activities. Eight (26%) ruptures followed prodromal symptoms of nonspecific pain in the region. Virtually all ruptures were treated surgically, with complete or near-complete ultimate restoration of function. AAS abusers, compared with otherwise similar bodybuilders, showed a markedly increased risk of tendon ruptures, particularly upper-body tendon rupture. © 2015 The Author(s).

Isolation and characterization of 2 new human rotator cuff and long head of biceps tendon cells possessing stem cell-like self-renewal and multipotential differentiation capacity.

PubMed

Randelli, Pietro; Conforti, Erika; Piccoli, Marco; Ragone, Vincenza; Creo, Pasquale; Cirillo, Federica; Masuzzo, Pamela; Tringali, Cristina; Cabitza, Paolo; Tettamanti, Guido; Gagliano, Nicoletta; Anastasia, Luigi

2013-07-01

Stem cell therapy is expected to offer new alternatives to the traditional therapies of rotator cuff tendon tears. In particular, resident, tissue-specific, adult stem cells seem to have a higher regenerative potential for the tissue where they reside. Rotator cuff tendon and long head of the biceps tendon possess a resident stem cell population that, when properly stimulated, may be induced to proliferate, thus being potentially usable for tendon regeneration. Controlled laboratory study. Human tendon samples from the supraspinatus and the long head of the biceps were collected during rotator cuff tendon surgeries from 26 patients, washed with phosphate-buffered saline, cut into small pieces, and digested with collagenase type I and dispase. After centrifugation, cell pellets were resuspended in appropriate culture medium and plated. Adherent cells were cultured, phenotypically characterized, and then compared with human bone marrow stromal cells (BMSCs), as an example of adult stem cells, and human dermal fibroblasts, as normal proliferating cells with no stem cell properties. Two new adult stem cell populations from the supraspinatus and long head of the biceps tendons were isolated, characterized, and cultured in vitro. Cells showed adult stem cell characteristics (ie, they were self-renewing in vitro, clonogenic, and multipotent), as they could be induced to differentiate into different cell types--namely, osteoblasts, adipocytes, and skeletal muscle cells. This work demonstrated that human rotator cuff tendon stem cells and human long head of the biceps tendon stem cells can be isolated and possess a high regenerative potential, which is comparable with that of BMSCs. Moreover, comparative analysis of the sphingolipid pattern of isolated cells with that of BMSCs and fibroblasts revealed the possibility of using this class of lipids as new possible markers of the cell differentiation status. Rotator cuff and long head of the biceps tendons contain a stem cell population that can proliferate in vitro and could constitute an easily accessible stem cell source to develop novel therapies for tendon regeneration.

Midportion achilles tendon microcirculation after intermittent combined cryotherapy and compression compared with cryotherapy alone: a randomized trial.

PubMed

Knobloch, Karsten; Grasemann, Ruth; Spies, Marcus; Vogt, Peter M

2008-11-01

The effect of combined cryotherapy/compression versus cryotherapy alone on the Achilles tendon is undetermined. Standardized combined cryotherapy/compression changes in midportion Achilles tendon microcirculation are superior to those with cryotherapy during intermittent application. Controlled laboratory study. Sixty volunteers were randomized for either combined cryotherapy/compression (Cryo/Cuff, DJO Inc, Vista, California: n = 30; 32 +/- 11 years) or cryotherapy alone (KoldBlue, TLP Industries, Kent, United Kingdom: n = 30; 33 +/- 12 years) with intermittent 3 x 10-minute application. Midportion Achilles tendon microcirculation was determined (O2C, LEA Medizintechnik, Giessen, Germany). Both Cryo/Cuff and KoldBlue significantly reduced superficial and deep capillary tendon blood flow within the first minute of application (43 +/- 46 arbitrary units [AU] vs 10 +/- 19 AU and 42 +/- 46 AU vs 12 +/- 10 AU; P = .0001) without a significant difference throughout all 3 applications. However, during recovery, superficial and deep capillary blood flow was reestablished significantly faster using Cryo/Cuff (P = .023). Tendon oxygen saturation was reduced in both groups significantly (3 minutes Cryo/Cuff: 36% +/- 20% vs 16% +/- 15%; KoldBlue: 42% +/- 19% vs 28% +/- 20%; P < .05) with significantly stronger effects using Cryo/Cuff (P = .014). Cryo/Cuff led to significantly higher tendon oxygenation (Cryo/Cuff: 62% +/- 28% vs baseline 36% +/- 20%; P = .0001) in superficial and deep tissue (Cryo/Cuff: 73% +/- 14% vs baseline 65% +/- 17%; P = .0001) compared with KoldBlue during all recoveries. Postcapillary venous filling pressures were significantly reduced in both groups during application; however, Cryo/Cuff led to significantly, but marginally, lower pressures (Cryo/Cuff: 41 +/- 7 AU vs baseline 51 +/- 13 AU; P = .0001 and KoldBlue: 46 +/- 7 AU vs baseline 56 +/- 11 AU; P = .026 for Cryo/Cuff vs KoldBlue). Increased tendon oxygenation is achieved as tendon preconditioning by combined cryotherapy and compression with significantly increased tendon oxygen saturation during recovery in contrast to cryotherapy alone. Both regimens lead to a significant amelioration of tendinous venous outflow. Combined cryotherapy and compression is superior to cryotherapy alone regarding the Achilles tendon microcirculation. Further studies in tendinopathy and tendon rehabilitation are warranted to elucidate its value regarding functional issues.

Assessment of Postoperative Tendon Quality in Patients With Achilles Tendon Rupture Using Diffusion Tensor Imaging and Tendon Fiber Tracking.

PubMed

Sarman, Hakan; Atmaca, Halil; Cakir, Ozgur; Muezzinoglu, Umit Sefa; Anik, Yonca; Memisoglu, Kaya; Baran, Tuncay; Isik, Cengiz

2015-01-01

Although pre- and postoperative imaging of Achilles tendon rupture (ATR) has been well documented, radiographic evaluations of postoperative intratendinous healing and microstructure are still lacking. Diffusion tensor imaging (DTI) is an innovative technique that offers a noninvasive method for describing the microstructure characteristics and organization of tissues. DTI was used in the present study for quantitative assessment of fiber continuity postoperatively in patients with acute ATR. The data from 16 patients with ATR from 2005 to 2012 were retrospectively analyzed. The microstructure of ART was evaluated using tendon fiber tracking, tendon continuity, fractional anisotropy, and apparent diffusion coefficient values by way of DTI. The distal and proximal portions were measured separately in both the ruptured and the healthy extremities of each patient. The mean patient age was 41.56 ± 8.49 (range 26 to 56) years. The median duration of follow-up was 21 (range 6 to 80) months. The tendon fractional anisotropy values of the ruptured Achilles tendon were significantly lower statistically than those of the normal side (p = .001). However, none of the differences between the 2 groups with respect to the distal and proximal apparent diffusion coefficient were statistically significant (p = .358 and p = .899, respectively). In addition, the fractional anisotropy and apparent diffusion coefficient measurements were not significantly different in the proximal and distal regions of the ruptured tendons compared with the healthy tendons. The present study used DTI and fiber tracking to demonstrate the radiologic properties of postoperative Achilles tendons with respect to trajectory and tendinous fiber continuity. Quantifying DTI and fiber tractography offers an innovative and effective tool that might be able to detect microstructural abnormalities not appreciable using conventional radiologic techniques. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

High-resolution study of the 3D collagen fibrillary matrix of Achilles tendons without tissue labelling and dehydrating.

PubMed

Wu, Jian-Ping; Swift, Benjamin John; Becker, Thomas; Squelch, Andrew; Wang, Allan; Zheng, Yong-Chang; Zhao, Xuelin; Xu, Jiake; Xue, Wei; Zheng, Minghao; Lloyd, David; Kirk, Thomas Brett

2017-06-01

Knowledge of the collagen structure of an Achilles tendon is critical to comprehend the physiology, biomechanics, homeostasis and remodelling of the tissue. Despite intensive studies, there are still uncertainties regarding the microstructure. The majority of studies have examined the longitudinally arranged collagen fibrils as they are primarily attributed to the principal tensile strength of the tendon. Few studies have considered the structural integrity of the entire three-dimensional (3D) collagen meshwork, and how the longitudinal collagen fibrils are integrated as a strong unit in a 3D domain to provide the tendons with the essential tensile properties. Using second harmonic generation imaging, a 3D imaging technique was developed and used to study the 3D collagen matrix in the midportion of Achilles tendons without tissue labelling and dehydration. Therefore, the 3D collagen structure is presented in a condition closely representative of the in vivo status. Atomic force microscopy studies have confirmed that second harmonic generation reveals the internal collagen matrix of tendons in 3D at a fibril level. Achilles tendons primarily contain longitudinal collagen fibrils that braid spatially into a dense rope-like collagen meshwork and are encapsulated or wound tightly by the oblique collagen fibrils emanating from the epitenon region. The arrangement of the collagen fibrils provides the longitudinal fibrils with essential structural integrity and endows the tendon with the unique mechanical function for withstanding tensile stresses. A novel 3D microscopic method has been developed to examine the 3D collagen microstructure of tendons without tissue dehydrating and labelling. The study also provides new knowledge about the collagen microstructure in an Achilles tendon, which enables understanding of the function of the tissue. The knowledge may be important for applying surgical and tissue engineering techniques to tendon reconstruction. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

Regional strain variations in the human patellar tendon.

PubMed

Pearson, Stephen J; Ritchings, Tim; Mohamed, Azlan S A

2014-07-01

Characteristics of localized tendon strain in vivo are largely unknown. The present study examines local tendon strain between the deep, middle, and surface structures at the proximal and distal aspects of the patellar tendon during ramped isometric contractions. Male subjects (age 28.0 ± 6.3 yr) were examined for patellar tendon excursion (anterior, midsection, and posterior) during ramped isometric voluntary contractions using real-time B-mode ultrasonography and dynamometry. Regional tendon excursion measurements were compared using an automated pixel tracking method. Strain was determined from the tendon delta length normalized to initial/resting segment length. Strain increased from 10% to 100% of force for all regions. Significantly greater mean strain was seen for the anterior proximal region compared to the posterior and mid layer of the tendon (7.5% ± 1.1% vs 3.7% ± 0.5% vs 5.5% ± 1.0%; P < 0.05). Similarly, the distal posterior region showed greater mean strain compared to the mid and anterior regions (7.9% ± 0.6% vs 5.0% ± 0.6% vs 5.4% ± 0.6%; P < 0.05). Relative changes in strain differences from 50% to 100% of force for the proximal region were greatest for the anterior to midline regions (4.6% ± 0.6% and 5.6% ± 0.6%, respectively) and those for the distal region were also greatest for the anterior to midline regions (4.4% ± 0.2% and 5.3% ± 0.2%, respectively). The largest mean strain for the proximal region was at the anterior layer (7.5% ± 1.1%) and that for the distal tendon region was at the posterior layer (7.9% ± 0.9%). This study shows significant regional differences in strain during ramped isometric contractions for the patellar tendon. Lower proximal strains in the posterior tendon compared to the anterior region may be associated with the suggestion of "stress shielding" as an etiological factor in insertional tendinopathy.

Finite Element Analysis of Grouting Compactness Monitoring in a Post-Tensioning Tendon Duct Using Piezoceramic Transducers

PubMed Central

Jiang, Tianyong; Song, Gangbing

2017-01-01

With the development of the post-tensioning technique, prestressed concrete structures have been widely used in civil engineering. To ensure the long-term effectiveness of the prestressed tendon, the grouting quality of the tendon duct is one of the important factors. However, it is still a challenge to monitor the grouting quality of post-tensioning tendon ducts, due to the invisibility of the grouting. The authors’ previous work proposed a real-time method that employed a stress wave-based active sensing approach with piezoceramic transducers to monitor the grouting compactness of a Post-Tensioning Tendon Duct (PTTD). To further understand the piezoceramic induced stress wave propagation in the PTTD with different grouting levels, this paper develops a two-dimensional finite element model for monitoring the grouting compactness of the tendon duct with a piezoceramic transducer. A smart aggregate (SA) developed to utilize one Lead Zirconate Titanate (PZT) transducer with marble protection is installed in the center location of the tendon duct as an actuator. Two PZT patches are bonded on the bottom and top surface of the tendon duct as the sensors. The analysis results show that the finite element analysis results are in good agreement with the experimental results, which demonstrates that the finite element analysis is feasible and reliable. For the top half of the specimen, not much stress wave could be detected before the full grouting level, except for negligible signals that may propagate through the walls of the tendon duct. When the tendon duct grouting is at 100%, the stress wave propagates to the top of the specimen, and the displacements are symmetric in both left-right and top-bottom directions before the stress waves reach the boundary. The proposed two-dimensional finite element model has the potential to be implemented to simulate the stress wave propagation principle for monitoring grouting compaction of the post-tensioning tendon duct. PMID:28961173

Finite Element Analysis of Grouting Compactness Monitoring in a Post-Tensioning Tendon Duct Using Piezoceramic Transducers.

PubMed

Jiang, Tianyong; Zheng, Junbo; Huo, Linsheng; Song, Gangbing

2017-09-29

With the development of the post-tensioning technique, prestressed concrete structures have been widely used in civil engineering. To ensure the long-term effectiveness of the prestressed tendon, the grouting quality of the tendon duct is one of the important factors. However, it is still a challenge to monitor the grouting quality of post-tensioning tendon ducts, due to the invisibility of the grouting. The authors' previous work proposed a real-time method that employed a stress wave-based active sensing approach with piezoceramic transducers to monitor the grouting compactness of a Post-Tensioning Tendon Duct (PTTD). To further understand the piezoceramic induced stress wave propagation in the PTTD with different grouting levels, this paper develops a two-dimensional finite element model for monitoring the grouting compactness of the tendon duct with a piezoceramic transducer. A smart aggregate (SA) developed to utilize one Lead Zirconate Titanate (PZT) transducer with marble protection is installed in the center location of the tendon duct as an actuator. Two PZT patches are bonded on the bottom and top surface of the tendon duct as the sensors. The analysis results show that the finite element analysis results are in good agreement with the experimental results, which demonstrates that the finite element analysis is feasible and reliable. For the top half of the specimen, not much stress wave could be detected before the full grouting level, except for negligible signals that may propagate through the walls of the tendon duct. When the tendon duct grouting is at 100%, the stress wave propagates to the top of the specimen, and the displacements are symmetric in both left-right and top-bottom directions before the stress waves reach the boundary. The proposed two-dimensional finite element model has the potential to be implemented to simulate the stress wave propagation principle for monitoring grouting compaction of the post-tensioning tendon duct.

Eccentric Training for Tendon Healing After Acute Lesion: A Rat Model.

PubMed

Kaux, Jean-François; Libertiaux, Vincent; Leprince, Pierre; Fillet, Marianne; Denoel, Vincent; Wyss, Clémence; Lecut, Christelle; Gothot, André; Le Goff, Caroline; Croisier, Jean-Louis; Crielaard, Jean-Michel; Drion, Pierre

2017-05-01

The tendon is a dynamic entity that remodels permanently. Platelet-rich plasma (PRP) injection has been shown to have a beneficial effect on tendon healing after lesion in rats. Furthermore, eccentric exercise seems to improve the mechanical quality of the tendon. A combination of PRP injection and eccentric training might be more effective than either treatment alone. Controlled laboratory study. Adult male rats were anesthetized, an incision was performed in the middle of their left patellar tendon and an injection of physiological fluid (PF) or homologous PRP was randomly made at the lesion level. The rats were then divided into 2 groups: the eccentric group, undergoing eccentric training 3 times a week, and the untrained group, without any training. Thus, 4 groups were compared. After 5 weeks, the tendons were removed and their ultimate tensile strength and energy were measured. Tendons were frozen for proteomic analyses when all biomechanical tests were completed. Statistical analysis was performed with linear mixed effect models. No significant difference was found between the treatments using PF injection or PRP injection alone. However, the value of the ultimate tensile force at rupture was increased by 4.5 N (108% of control, P = .006) when eccentric training was performed. An intragroup analysis revealed that eccentric training significantly improved the ultimate force values for the PRP group. Proteomic analysis revealed that eccentric training led to an increase in abundance of several cytoskeletal proteins in the PF group, while a decrease in abundance of enzymes of the glycolytic pathway occurred in the PRP-treated groups, indicating that this treatment might redirect the exercise-driven metabolic plasticity of the tendon. Eccentric training altered the metabolic plasticity of tendon and led to an improvement of injured tendon resistance regardless of the treatment injected (PF or PRP). This study demonstrates the necessity of eccentric rehabilitation and training in cases of tendon lesion regardless of the treatment carried out.

Effect of Achilles tendon loading on plantar fascia tension in the standing foot.

PubMed

Cheung, Jason Tak-Man; Zhang, Ming; An, Kai-Nan

2006-02-01

The plantar fascia, which is one of the major arch-supporting structures of the human foot, sustains high tensions during weight-bearing. A positive correlation between Achilles tendon loading and plantar fascia tension has been reported. Excessive stretching and tightness of the Achilles tendon are thought to be the risk factors of plantar fasciitis but their biomechanical effects on the plantar fascia have not been fully addressed. A three-dimensional finite element model of the human foot and ankle, incorporating geometrical and material nonlinearity, was employed to investigate the loading response of the plantar fascia in the standing foot with different magnitudes of Achilles tendon loading. With the total ground reaction forces of one foot maintained at 350 N to represent half body weight, an increase in Achilles tendon load from (0-700 N) resulted in a general increase in total force and peak plantar pressure at the forefoot of up to about 250%. There was a lateral and anterior shift of the centre of pressure and a reduction in the arch height with an increasing Achilles tendon load as a result of the plantar flexion moment on the calcaneus. From the finite element predictions of simulated balanced standing, Achilles tendon forces of 75% of the total weight on the foot (350 N) were found to provide the closest match of the measured centre of pressure of the subject during balanced standing. Both the weight on the foot and Achilles tendon loading resulted in an increase in tension of the plantar fascia with the latter showing a two-times larger straining effect. Increasing tension on the Achilles tendon is coupled with an increasing strain on the plantar fascia. Overstretching of the Achilles tendon resulting from intense muscle contraction and passive stretching of tight Achilles tendon are plausible mechanical factors for overstraining of the plantar fascia.

Synthesis of embryonic tendon-like tissue by human marrow stromal/mesenchymal stem cells requires a three-dimensional environment and transforming growth factor β3.

PubMed

Kapacee, Zoher; Yeung, Ching-Yan Chloé; Lu, Yinhui; Crabtree, David; Holmes, David F; Kadler, Karl E

2010-10-01

Tendon-like tissue generated from stem cells in vitro has the potential to replace tendons and ligaments lost through injury and disease. However, thus far, no information has been available on the mechanism of tendon formation in vitro and how to accelerate the process. We show here that human mesenchymal stem cells (MSCs) and bone marrow-derived mononuclear cells (BM-MNCs) can generate tendon-like tissue in 7days mediated by transforming growth factor (TGF) β3. MSCs cultured in fixed-length fibrin gels spontaneously synthesized narrow-diameter collagen fibrils and exhibited fibripositors (actin-rich, collagen fibril-containing plasma membrane protrusions) identical to those that occur in embryonic tendon. In contrast, BM-MNCs did not synthesize tendon-like tissue under these conditions. We performed real-time PCR analysis of MSCs and BM-MNCs. MSCs upregulated genes encoding type I collagen, TGFβ3, and Smad2 at the time of maximum contraction of the tendon-like tissue (7days). Western blot analysis showed phosphorylation of Smad2 at maximum contraction. The TGFβ inhibitor SB-431542, blocked the phosphorylation of Smad2 and stopped the formation of tendon-like tissue. Quantitative PCR showed that BM-MNCs expressed very low levels of TGFβ3 compared to MSCs. Therefore we added exogenous TGFβ3 protein to BM-MNCs in fibrin gels, which resulted in phosphorylation of Smad2, synthesis of collagen fibrils, the appearance of fibripositors at the plasma membrane, and the formation of tendon-like tissue. In conclusion, MSCs that self-generate TGFβ signaling or the addition of TGFβ3 protein to BM-MNCs in fixed-length fibrin gels spontaneously make embryonic tendon-like tissue in vitro within 7days. Copyright © 2010 International Society of Matrix Biology. Published by Elsevier B.V. All rights reserved.

Intermittent KoldBlue cryotherapy of 3x10 min changes mid-portion Achilles tendon microcirculation.

PubMed

Knobloch, Karsten; Grasemann, Ruth; Spies, Marcus; Vogt, Peter M

2007-06-01

Neovascularisation and microcirculatory changes have been reported in Achilles tendinopathy. Cryotherapy and compression, as part of a rest, ice, compression and elevation regimen, are shown to decrease pain and improve function. However, the microcirculatory changes following a given dosage of cryotherapy on mid-portion Achilles tendon remain unclear. Prospective clinical cohort study, level of evidence 2. 30 people (12 males, 33 (SD 12) years, body mass index 25.6 (5.3) kg/m2) were included in the cohort. 3x10 min KoldBlue ankle-cooling bandages were applied and microcirculation of Achilles tendon mid-portion was real-time and continuously assessed using a laser-Doppler-spectrophotometry system (O2C, Germany). Superficial capillary blood flow was reduced from 42 to 6, 5 and 3 relative units (rU) in the first, second and third cryotherapy periods, respectively (-65%, p = 0.001), with no significant capillary hyperaemia. Deep capillary tendon blood flow was reduced from 180 to 82, 53 and 52 rU (-71%, p = 0.001) within 6-9 min of application without hyperaemia. Superficial tendon oxygen saturation dropped significantly from 43% to 26%, 18% and 11% (p = 0.001) after repetitive cryotherapy, with persisting increase of tendon oxygenation during rewarming (51%, 49% and 54%, p = 0.077) up to 27% of the baseline level. At 8 mm tendon depth, cryotherapy preserved local oxygenation. Relative postcapillary venous tendon filling pressures were favourably reduced from 41 (11) to 31, 28 and 26 rU (-36%, p = 0.001) superficially and from 56 (11) to 45, 46 and 48 rU (-18%, p = 0.001) in deep capillary blood flow during cryotherapy, facilitating capillary venous clearance. Intermittent cryotherapy of 3x10 min significantly decreases local Achilles tendon mid-portion capillary blood flow by 71%. Within 2 min of rewarming, tendon oxygen saturation is re-established following cryotherapy. Postcapillary venous filling pressures are reduced during cryotherapy, favouring capillary venous outflow of the healthy Achilles tendon.

Descriptive analysis of retirement of Thoroughbred racehorses due to tendon injuries at the Hong Kong Jockey Club (1992-2004).

PubMed

Lam, K H; Parkin, T D H; Riggs, C M; Morgan, K L

2007-03-01

This study was part of a programme to optimise the longevity and maximise the health and welfare of the Thoroughbred racehorses in Hong Kong. Injuries to the superficial digital flexor (SDF) tendon are the most common veterinary reason for premature retirement in this population. To describe the frequency and pattern of retirements associated with SDF tendon injuries in Thoroughbred racehorses and to compare the characteristics of these horses with those that retired for other reasons. A retrospective analysis of retirement records documented in the Hong Kong Jockey Club clinical database between 1992 and 2004 was conducted. As this is complete census data, no statistical inference to the population is necessary. The mean annual cumulative incidence of retirements due to tendon injury was 3.2% accounting for 14% of all retirements. The risk of tendon injury increased over the 12 year period from 23-4.2%. The racing career, number of starts and earnings of horses retired with tendon injuries were reduced by 25.6, 41.2 and 53.3%, respectively. Thirteen percent of these horses never raced in Hong Kong. A greater proportion of 3- and 4-year-olds and entire males were retired because of tendon injuries. Ninety-seven percent of injuries affected the forelimb, the right more frequently than the left. Only 19.7% of retired horses that had received ultrasound examination for SDF tendon injury retired for this reason. This study provides population based data on the frequency, career and economic losses associated with tendon injury induced retirement. This descriptive study has provided a useful resource for further case-control studies to investigate risk factors for retirement from racing due to tendon injury. This is the first step toward the development of management tools to reduce the incidence of tendon injury related retirement in Hong Kong.

Surgical repair of chronic patellar tendon rupture in total knee replacement with ipsilateral hamstring tendons.

PubMed

Spoliti, Marco; Giai Via, Alessio; Padulo, Johnny; Oliva, Francesco; Del Buono, Angelo; Maffulli, Nicola

2016-10-01

Patellar tendon rupture is a serious complication of total knee arthroplasty (TKA). Its reconstruction in patients with chronic ruptures is technically demanding. This article reports the results of surgical reconstruction of neglected patellar tendon rupture in TKA using autologous hamstring tendons. Nine TKA patients (six women and three men) (mean age at index surgery 68 years) with chronic patellar tendon tears underwent reconstruction with ipsilateral hamstrings tendon, leaving the distal insertion in situ. The clinical diagnosis was supported by imaging (anterior-posterior and 30° flexion lateral radiographs). Insall-Salvati index, range of motion, and leg extension test were recorded preoperatively and at last follow-up. The modified Cincinnati rating system and the Kujala score were administered. The patients sustained the patellar tendon tear an average of 8 weeks before the procedure. At final follow-up of 4 years (range 2-8 years), the median of extension lag was 5° (range 0°-15°; DS = 5). The median of post-operative Insall-Salvati index was 1.4 (range 1.3-1.8; SD = 0.15; p = 0.002) compared to the preoperative index of 1.7 (range 1.5-2.2; SD = 0.23). The mean modified Cincinnati and Kujala scores significantly increased compared with the preoperative ones (p < 0.01). At final follow-up, all patients were able to walk without brace or aids, and they were satisfied with the procedure. Based on our retrospective study of nine patients, reconstruction of neglected patellar tendon rupture in TKA with autologous hamstring tendons is feasible and safe, and provides good functional recovery. Case series, Level IV.

Use of fluroquinolone and risk of Achilles tendon rupture: a population-based cohort study.

PubMed

Sode, Jacob; Obel, Niels; Hallas, Jesper; Lassen, Annmarie

2007-05-01

Several case-control studies have reported that the use of fluoroquinolone increases the risk of rupture of the Achilles tendon. Our aim was to estimate this risk by means of a population-based cohort approach. Data on Achilles tendon ruptures and fluoroquinolone use were retrieved from three population-based databases that include information on residents of Funen County (population: 470,000) in primary and secondary care during the period 1991-1999. A study cohort of all 28,262 first-time users of fluoroquinolone and all incident cases of Achilles tendon ruptures were identified. The incidence rate of Achilles tendon ruptures among users and non-users of fluoroquinolones and the standardised incidence rate ratio associating fluoroquinolon use with Achilles tendon rupture were the main outcome measures. Between 1991 and 2002 the incidence of Achilles tendon rupture increased from 22.1 to 32.6/100,000 person-years. Between 1991 and 1999 the incidence of fluoroquinolone users was 722/100,000 person-years, with no apparent trend over time. Within 90 days of their first use of fluoroquinolone, five individuals had a rupture of the Achilles tendon; the expected number was 1.6, yielding an age- and sex-standardised incidence ratio of 3.1 [(95% confidence interval (95%CI): 1.0-7.3). The 90-day cumulative incidence of Achilles tendon ruptures among fluoroquinolone users was 17.7/100,000 (95%CI: 5.7-41.3), which is an increase of 12.0/100,000 (95%CI: 0.0-35.6) compared to the background population. Fluoroquinolone use triples the risk of Achilles tendon rupture, but the incidence among users is low.

Gap junction protein expression and cellularity: comparison of immature and adult equine digital tendons

PubMed Central

Stanley, Rachael L; Fleck, Roland A; Becker, David L; Goodship, Allen E; Ralphs, Jim R; Patterson-Kane, Janet C

2007-01-01

Injury to the energy-storing superficial digital flexor tendon is common in equine athletes and is age-related. Tenocytes in the superficial digital flexor tendon of adult horses appear to have limited ability to respond adaptively to exercise or prevent the accumulation of strain-induced microdamage. It has been suggested that conditioning exercise should be introduced during the growth period, when tenocytes may be more responsive to increased quantities or intensities of mechanical strain. Tenocytes are linked into networks by gap junctions that allow coordination of synthetic activity and facilitate strain-induced collagen synthesis. We hypothesised that there are reductions in cellular expression of the gap junction proteins connexin (Cx) 43 and 32 during maturation and ageing of the superficial digital flexor tendon that do not occur in the non-injury-prone common digital extensor tendon. Cryosections from the superficial digital flexor tendon and common digital extensor tendon of 5 fetuses, 5 foals (1–6 months), 5 young adults (2–7 years) and 5 old horses (18–33 years) were immunofluorescently labelled and quantitative confocal laser microscopy was performed. Expression of Cx43 and Cx32 protein per tenocyte was significantly higher in the fetal group compared with all other age groups in both tendons. The density of tenocytes was found to be highest in immature tissue. Higher levels of cellularity and connexin protein expression in immature tendons are likely to relate to requirements for tissue remodelling and growth. However, if further studies demonstrate that this correlates with greater gap junctional communication efficiency and synthetic responsiveness to mechanical strain in immature compared with adult tendons, it could support the concept of early introduction of controlled exercise as a means of increasing resistance to later injury. PMID:17848160

Tendon length and joint flexibility are related to running economy.

PubMed

Hunter, Gary R; Katsoulis, Konstantina; McCarthy, John P; Ogard, William K; Bamman, Marcas M; Wood, David S; Den Hollander, Jan A; Blaudeau, Tamilane E; Newcomer, Bradley R

2011-08-01

The purpose of study was to determine whether quadriceps/patella and Achilles tendon length and flexibility of the knee extensors and plantar flexors are related to walking and running economy. Twenty-one male distance runners were subjects. Quadriceps/patella and Achilles tendon length were measured by magnetic resonance imaging; body composition was measured DXA; oxygen uptake at rest while seated, walking (3 mph), and running (6 and 7 mph) were measured by indirect calorimetry; knee and ankle joint flexibility were measured by goniometry; and leg lengths were measured by anthropometry while seated. Correlations were used to identify relationships between variables of interest. Net VO2 (exercise VO2 - rest VO2) for walking (NVOWK) and running at 6 and 7 mph (NVO6 and NVO7, respectively) was significantly related to Achilles tendon length (r varying from -0.40 to -0.51, P all < 0.04). Achilles tendon cross section was not related to walking or running economy. Quadriceps/patella tendon length was significantly related to NVO7 (r = -0.43, P = 0.03) and approached significance for NVO6 (r = -0.36, P = 0.06). Flexibility of the plantar flexors was related to NVO7 (+0.38, P = 0.05). Multiple regression showed that Achilles tendon length was independently related to NVO6 and NVO7 (partial r varying from -0.53 to -0.64, all P < 0.02) independent of lower leg length, upper leg length, quadriceps/patella tendon length, knee extension flexibility, or plantarflexion flexibility. These data support the premise that longer lower limb tendons (especially Achilles tendon) and less flexible lower limb joints are associated with improved running economy.

Imbalances in the Development of Muscle and Tendon as Risk Factor for Tendinopathies in Youth Athletes: A Review of Current Evidence and Concepts of Prevention

PubMed Central

Mersmann, Falk; Bohm, Sebastian; Arampatzis, Adamantios

2017-01-01

Tendons feature the crucial role to transmit the forces exerted by the muscles to the skeleton. Thus, an increase of the force generating capacity of a muscle needs to go in line with a corresponding modulation of the mechanical properties of the associated tendon to avoid potential harm to the integrity of the tendinous tissue. However, as summarized in the present narrative review, muscle and tendon differ with regard to both the time course of adaptation to mechanical loading as well as the responsiveness to certain types of mechanical stimulation. Plyometric loading, for example, seems to be a more potent stimulus for muscle compared to tendon adaptation. In growing athletes, the increased levels of circulating sex hormones might additionally augment an imbalanced development of muscle strength and tendon mechanical properties, which could potentially relate to the increasing incidence of tendon overload injuries that has been indicated for adolescence. In fact, increased tendon stress and strain due to a non-uniform musculotendinous development has been observed recently in adolescent volleyball athletes, a high-risk group for tendinopathy. These findings highlight the importance to deepen the current understanding of the interaction of loading and maturation and demonstrate the need for the development of preventive strategies. Therefore, this review concludes with an evidence-based concept for a specific loading program for increasing tendon stiffness, which could be implemented in the training regimen of young athletes at risk for tendinopathy. This program incorporates five sets of four contractions with an intensity of 85–90% of the isometric voluntary maximum and a movement/contraction duration that provides 3 s of high magnitude tendon strain. PMID:29249987

Expression of collagen and related growth factors in rat tendon and skeletal muscle in response to specific contraction types

PubMed Central

Heinemeier, K M; Olesen, J L; Haddad, F; Langberg, H; Kjaer, M; Baldwin, K M; Schjerling, P

2007-01-01

Acute exercise induces collagen synthesis in both tendon and muscle, indicating an adaptive response in the connective tissue of the muscle–tendon unit. However, the mechanisms of this adaptation, potentially involving collagen-inducing growth factors (such as transforming growth factor-β-1 (TGF-β-1)), as well as enzymes related to collagen processing, are not clear. Furthermore, possible differential effects of specific contraction types on collagen regulation have not been investigated. Female Sprague–Dawley rats were subjected to 4 days of concentric, eccentric or isometric training (n = 7–9 per group) of the medial gastrocnemius, by stimulation of the sciatic nerve. RNA was extracted from medial gastrocnemius and Achilles tendon tissue 24 h after the last training bout, and mRNA levels for collagens I and III, TGF-β-1, connective tissue growth factor (CTGF), lysyl oxidase (LOX), metalloproteinases (MMP-2 and -9) and their inhibitors (TIMP-1 and 2) were measured by Northern blotting and/or real-time PCR. In tendon, expression of TGF-β-1 and collagens I and III (but not CTGF) increased in response to all types of training. Similarly, enzymes/factors involved in collagen processing were induced in tendon, especially LOX (up to 37-fold), which could indicate a loading-induced increase in cross-linking of tendon collagen. In skeletal muscle, a similar regulation of gene expression was observed, but in contrast to the tendon response, the effect of eccentric training was significantly greater than the effect of concentric training on the expression of several transcripts. In conclusion, the study supports an involvement of TGF-β-1 in loading-induced collagen synthesis in the muscle–tendon unit and importantly, it indicates that muscle tissue is more sensitive than tendon to the specific mechanical stimulus. PMID:17540706

Expression of collagen and related growth factors in rat tendon and skeletal muscle in response to specific contraction types.

PubMed

Heinemeier, K M; Olesen, J L; Haddad, F; Langberg, H; Kjaer, M; Baldwin, K M; Schjerling, P

2007-08-01

Acute exercise induces collagen synthesis in both tendon and muscle, indicating an adaptive response in the connective tissue of the muscle-tendon unit. However, the mechanisms of this adaptation, potentially involving collagen-inducing growth factors (such as transforming growth factor-beta-1 (TGF-beta-1)), as well as enzymes related to collagen processing, are not clear. Furthermore, possible differential effects of specific contraction types on collagen regulation have not been investigated. Female Sprague-Dawley rats were subjected to 4 days of concentric, eccentric or isometric training (n = 7-9 per group) of the medial gastrocnemius, by stimulation of the sciatic nerve. RNA was extracted from medial gastrocnemius and Achilles tendon tissue 24 h after the last training bout, and mRNA levels for collagens I and III, TGF-beta-1, connective tissue growth factor (CTGF), lysyl oxidase (LOX), metalloproteinases (MMP-2 and -9) and their inhibitors (TIMP-1 and 2) were measured by Northern blotting and/or real-time PCR. In tendon, expression of TGF-beta-1 and collagens I and III (but not CTGF) increased in response to all types of training. Similarly, enzymes/factors involved in collagen processing were induced in tendon, especially LOX (up to 37-fold), which could indicate a loading-induced increase in cross-linking of tendon collagen. In skeletal muscle, a similar regulation of gene expression was observed, but in contrast to the tendon response, the effect of eccentric training was significantly greater than the effect of concentric training on the expression of several transcripts. In conclusion, the study supports an involvement of TGF-beta-1 in loading-induced collagen synthesis in the muscle-tendon unit and importantly, it indicates that muscle tissue is more sensitive than tendon to the specific mechanical stimulus.

The histology of tendon attachments to bone in man.

PubMed Central

Benjamin, M; Evans, E J; Copp, L

1986-01-01

Based on a parallel study of a wide range of human tendons from embalmed dissecting room subjects and from a study of dried bones, an explanation is offered for the well known similarity in gross appearance between the markings left by certain tendons (e.g. those of the rotator cuff) and by articular surfaces on dried bones. Epiphyseal tendons leave markings on bones that look like those left by articular surfaces. These tendons have a prominent zone of fibrocartilage at their attachment site and the deepest part of this is calcified, just as the deepest part of articular hyaline cartilage is calcified. After maceration of the soft tissues, the calcified (fibro) cartilage is left attached to the bone at articular surfaces and at the sites of tendon attachment. In all cases, the tissues separate at the basophilic tidemark between the calcified and uncalcified regions. This tidemark is smooth where there is much overlying uncalcified (fibro) cartilage and it is the smoothness that gives the typical appearance of the dried bone. Blood vessels do not generally traverse the tendon fibrocartilage plugs. Hence the areas are devoid of vascular foramina. The functional significance of tendon fibrocartilage is discussed with particular reference to supraspinatus. It is suggested that the uncalcified fibrocartilage ensures that the tendon fibres do not bend, splay out or become compressed at a hard tissue interface, and are thereby offered some protection from wear and tear. It is also suggested that the fibrocartilage plug of supraspinatus prevents the tendon from rubbing on the head of the humerus. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 PMID:3693113

Exposure of a tendon extracellular matrix to synovial fluid triggers endogenous and engrafted cell death: A mechanism for failed healing of intrathecal tendon injuries.

PubMed

Garvican, Elaine R; Salavati, Mazdak; Smith, Roger K W; Dudhia, Jayesh

2017-09-01

The purpose of this study was to investigate the effect of normal synovial fluid (SF) on exposed endogenous tendon-derived cells (TDCs) and engrafted mesenchymal stem cells (MSCs) within the tendon extracellular matrix. Explants from equine superficial digital flexor (extra-synovial) and deep digital flexor tendons (DDFTs) from the compressed, intra-synovial and the tensile, extra-synovial regions were cultured in allogeneic or autologous SF-media. Human hamstring explants were cultured in allogeneic SF. Explant viability was assessed by staining. Proliferation of equine monolayer MSCs and TDCs in SF-media and co-culture with DDFT explants was determined by alamarblue®. Non-viable Native Tendon matrices (NNTs) were re-populated with MSCs or TDCs and cultured in SF-media. Immunohistochemical staining of tendon sections for the apoptotic proteins caspase-3, -8, and -9 was performed. Contact with autologous or allogeneic SF resulted in rapid death of resident tenocytes in equine and human tendon. SF did not affect the viability of equine epitenon cells, or of MSCs and TDCs in the monolayer or indirect explant co-culture. MSCs and TDCs, engrafted into NNTs, died when cultured in SF. Caspase-3, -8, and -9 expression was the greatest in SDFT explants exposed to allogeneic SF. The efficacy of cells administered intra-synovially for tendon lesion repair is likely to be limited, since once incorporated into the matrix, cells become vlnerable to the adverse effects of SF. These observations could account for the poor success rate of intra-synovial tendon healing following damage to the epitenon and contact with SF, common with most soft tissue intra-synovial pathologies.

Augmentation of Rotator Cuff Repair With Soft Tissue Scaffolds

PubMed Central

Thangarajah, Tanujan; Pendegrass, Catherine J.; Shahbazi, Shirin; Lambert, Simon; Alexander, Susan; Blunn, Gordon W.

2015-01-01

Background Tears of the rotator cuff are one of the most common tendon disorders. Treatment often includes surgical repair, but the rate of failure to gain or maintain healing has been reported to be as high as 94%. This has been substantially attributed to the inadequate capacity of tendon to heal once damaged, particularly to bone at the enthesis. A number of strategies have been developed to improve tendon-bone healing, tendon-tendon healing, and tendon regeneration. Scaffolds have received considerable attention for replacement, reconstruction, or reinforcement of tendon defects but may not possess situation-specific or durable mechanical and biological characteristics. Purpose To provide an overview of the biology of tendon-bone healing and the current scaffolds used to augment rotator cuff repairs. Study Design Systematic review; Level of evidence, 4. Methods A preliminary literature search of MEDLINE and Embase databases was performed using the terms rotator cuff scaffolds, rotator cuff augmentation, allografts for rotator cuff repair, xenografts for rotator cuff repair, and synthetic grafts for rotator cuff repair. Results The search identified 438 unique articles. Of these, 214 articles were irrelevant to the topic and were therefore excluded. This left a total of 224 studies that were suitable for analysis. Conclusion A number of novel biomaterials have been developed into biologically and mechanically favorable scaffolds. Few clinical trials have examined their effect on tendon-bone healing in well-designed, long-term follow-up studies with appropriate control groups. While there is still considerable work to be done before scaffolds are introduced into routine clinical practice, there does appear to be a clear indication for their use as an interpositional graft for large and massive retracted rotator cuff tears and when repairing a poor-quality degenerative tendon. PMID:26665095

Accuracy of open magnetic resonance imaging for guiding injection of the equine deep digital flexor tendon within the hoof.

PubMed

Groom, Lauren M; White, Nathaniel A; Adams, M Norris; Barrett, Jennifer G

2017-11-01

Lesions of the distal deep digital flexor tendon (DDFT) are frequently diagnosed using MRI in horses with foot pain. Intralesional injection of biologic therapeutics shows promise in tendon healing; however, accurate injection of distal deep digital flexor tendon lesions within the hoof is difficult. The aim of this experimental study was to evaluate accuracy of a technique for injection of the deep digital flexor tendon within the hoof using MRI-guidance, which could be performed in standing patients. We hypothesized that injection of the distal deep digital flexor tendon within the hoof could be accurately guided using open low-field MRI to target either the lateral or medial lobe at a specific location. Ten cadaver limbs were positioned in an open, low-field MRI unit. Each distal deep digital flexor tendon lobe was assigned to have a proximal (adjacent to the proximal aspect of the navicular bursa) or distal (adjacent to the navicular bone) injection. A titanium needle was inserted into each tendon lobe, guided by T1-weighted transverse images acquired simultaneously during injection. Colored dye was injected as a marker and postinjection MRI and gross sections were assessed. The success of injection as evaluated on gross section was 85% (70% proximal, 100% distal). The success of injection as evaluated by MRI was 65% (60% proximal, 70% distal). There was no significant difference between the success of injecting the medial versus lateral lobe. The major limitation of this study was the use of cadaver limbs with normal tendons. The authors conclude that injection of the distal deep digital flexor tendon within the hoof is possible using MRI guidance. © 2017 American College of Veterinary Radiology.

Achilles and patellar tendinopathy display opposite changes in elastic properties: A shear wave elastography study.

PubMed

Coombes, B K; Tucker, K; Vicenzino, B; Vuvan, V; Mellor, R; Heales, L; Nordez, A; Hug, F

2018-03-01

To compare tendon elastic and structural properties of healthy individuals with those with Achilles or patellar tendinopathy. Sixty-seven participants (22 Achilles tendinopathy, 17 patellar tendinopathy, and 28 healthy controls) were recruited between March 2015 and March 2016. Shear wave velocity (SWV), an index of tissue elastic modulus, and tendon thickness were measured bilaterally at mid-tendon and insertional regions of Achilles and patellar tendons by an examiner blinded to group. Analysis of covariance, adjusted for age, body mass index, and sex was used to compare differences in tendon thickness and SWV between the two tendinopathy groups (relative to controls) and regions. Tendon thickness was included as a covariate for analysis of SWV. Compared to controls, participants with Achilles tendinopathy had lower SWV at the distal insertion (Mean difference MD; 95% CI: -1.56; -2.49 to -0.62 m/s; P < .001) and greater thickness at the mid-tendon (MD 0.19; 0.05-0.33 cm; P = .007). Compared to controls, participants with patellar tendinopathy had higher SWV at both regions (MD 1.25; 0.40-2.10 m/s; P = .005) and greater thickness proximally (MD 0.17; 0.06-0.29 cm; P = .003). Compared to controls, participants with Achilles and patellar tendinopathy displayed lower Achilles tendon elastic modulus and higher patellar tendon elastic modulus, respectively. More research is needed to explore whether maturation, aging, or chronic load underlie these findings and whether current management programs for Achilles and patellar tendinopathy need to be tailored to the tendon. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Chronic inflammation is a feature of Achilles tendinopathy and rupture.

PubMed

Dakin, Stephanie Georgina; Newton, Julia; Martinez, Fernando O; Hedley, Robert; Gwilym, Stephen; Jones, Natasha; Reid, Hamish A B; Wood, Simon; Wells, Graham; Appleton, Louise; Wheway, Kim; Watkins, Bridget; Carr, Andrew Jonathan

2018-03-01

Recent investigation of human tissue and cells from positional tendons such as the rotator cuff has clarified the importance of inflammation in the development and progression of tendon disease. These mechanisms remain poorly understood in disease of energy-storing tendons such as the Achilles. Using tissue biopsies from patients, we investigated if inflammation is a feature of Achilles tendinopathy and rupture. We studied Achilles tendon biopsies from symptomatic patients with either mid-portion tendinopathy or rupture for evidence of abnormal inflammatory signatures. Tendon-derived stromal cells from healthy hamstring and diseased Achilles were cultured to determine the effects of cytokine treatment on expression of inflammatory markers. Tendinopathic and ruptured Achilles highly expressed CD14+ and CD68+ cells and showed a complex inflammation signature, involving NF-κB, interferon and STAT-6 activation pathways. Interferon markers IRF1 and IRF5 were highly expressed in tendinopathic samples. Achilles ruptures showed increased PTGS2 and interleukin-8 expression. Tendinopathic and ruptured Achilles tissues expressed stromal fibroblast activation markers podoplanin and CD106. Tendon cells isolated from diseased Achilles showed increased expression of pro-inflammatory and stromal fibroblast activation markers after cytokine stimulation compared with healthy hamstring tendon cells. Tissue and cells derived from tendinopathic and ruptured Achilles tendons show evidence of chronic (non-resolving) inflammation. The energy-storing Achilles shares common cellular and molecular inflammatory mechanisms with functionally distinct rotator cuff positional tendons. Differences seen in the profile of ruptured Achilles are likely to be attributable to a superimposed phase of acute inflammation and neo-vascularisation. Strategies that target chronic inflammation are of potential therapeutic benefit for patients with Achilles tendon disease. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Validation of color Doppler sonography for evaluating relative displacement between the flexor tendon and subsynovial connective tissue.

PubMed

Tat, Jimmy; Kociolek, Aaron M; Keir, Peter J

2015-04-01

A common pathologic finding in carpal tunnel syndrome is fibrosis and thickening of the subsynovial connective tissue. This finding suggests an etiology of excessive shear forces, with relative longitudinal displacement between the flexor tendon and adjacent subsynovial connective tissue. The purpose of this study was to validate color Doppler sonography for measurement of tendon displacement over time. Eight unmatched fresh frozen cadaver arms were used to evaluate color Doppler sonography for measurement of tendon displacement. The middle flexor digitorum superficialis tendon was moved through a physiologic excursion of 20 mm at 3 different tendon velocities (50, 100, and 150 mm/s). We found that color Doppler sonography provided accurate measurement of tendon displacement, with absolute errors of -0.05 mm (50 mm/s), -1.24 mm (100 mm/s), and -2.36 mm (150 mm/s) on average throughout the tendon excursion range. Evaluating relative displacement between the tendon and subsynovial connective tissue during finger flexion-extension movements also offered insight into the gliding mechanism of the subsynovial connective tissue. During flexion, we observed a curvilinear increase in relative displacement, with greater differential motion at the end range of displacement, likely due to the sequential stretch of the fibrils between successive layers of the subsynovial connective tissue. In extension, there was a linear return in relative displacement, suggesting a different unloading mechanism characterized by uniform relaxation of fibrils. We demonstrated the validity of color Doppler displacement for use in the evaluation of relative motion. Color Doppler sonography is useful in our understanding of the behavior of the subsynovial connective tissue during tendon excursion, which may elucidate the role of finger motion in the etiology of shear injury. © 2015 by the American Institute of Ultrasound in Medicine.

Mineralization can be an incidental ultrasonographic finding in equine tendons and ligaments.

PubMed

O'Brien, Etienne J O; Smith, Roger K W

2018-05-18

Tendon/ligament mineralization is recognized in horses but information regarding its clinical significance is limited. The aims of this observational study were to report the structures most commonly affected by ultrasonographically detectable mineralization and, for these, determine frequency of diagnosis and key clinical features. Cases presented at our hospital in April 1999-April 2013 and September 2014-November 2015 were included: a total of 27 horses (22 retrospective, five prospective). Mineralizations were most common in deep digital flexor tendons (10) and suspensory ligament branches (eight), representing 10% and 7% (estimated), respectively, of horses diagnosed with injuries to these structures during the study. Two deep digital flexor tendon and three suspensory ligament branch cases showed bilateral mineralization. Deep digital flexor tendon mineralization was restricted to the digital flexor tendon sheath, most commonly in the proximal sheath (±sesamoidean canal), and seven of 10 cases involved hindlimbs. Suspensory ligament branch mineralization was visible in the same ultrasound window as the proximal sesamoid bones in 10/11 limbs and six of eight cases involved forelimbs. Previous corticosteroid medication was a feature of one deep digital flexor tendon and one suspensory ligament branch case. Mineralization was associated with lameness in some but not all limbs. Mineralized foci within the deep digital flexor tendon preceded hypoechoic lesion formation in two limbs. Of the cases with deep digital flexor tendon or suspensory ligament branch injury only, one of three and two of three cases, respectively, became sound. Findings indicated that tendon/ligament mineralization can be associated with lameness in some horses, but can also be an incidental finding. © 2018 American College of Veterinary Radiology.

Mechanical, histological, and functional properties remain inferior in conservatively treated Achilles tendons in rodents: Long term evaluation.

PubMed

Freedman, Benjamin R; Fryhofer, George W; Salka, Nabeel S; Raja, Harina A; Hillin, Cody D; Nuss, Courtney A; Farber, Daniel C; Soslowsky, Louis J

2017-05-03

Conservative treatment (non-operative) of Achilles tendon ruptures is suggested to produce equivalent capacity for return to function; however, long term results and the role of return to activity (RTA) for this treatment paradigm remain unclear. Therefore, the objective of this study was to evaluate the long term response of conservatively treated Achilles tendons in rodents with varied RTA. Sprague Dawley rats (n=32) received unilateral blunt transection of the Achilles tendon followed by randomization into groups that returned to activity after 1-week (RTA1) or 3-weeks (RTA3) of limb casting in plantarflexion, before being euthanized at 16-weeks post-injury. Uninjured age-matched control animals were used as a control group (n=10). Limb function, passive joint mechanics, tendon properties (mechanical, histological), and muscle properties (histological, immunohistochemical) were evaluated. Results showed that although hindlimb ground reaction forces and range of motion returned to baseline levels by 16-weeks post-injury regardless of RTA, ankle joint stiffness remained altered. RTA1 and RTA3 groups both exhibited no differences in fatigue properties; however, the secant modulus, hysteresis, and laxity were inferior compared to uninjured age-matched control tendons. Despite these changes, tendons 16-weeks post-injury achieved secant stiffness levels of uninjured tendons. RTA1 and RTA3 groups had no differences in histological properties, but had higher cell numbers compared to control tendons. No changes in gastrocnemius fiber size or type in the superficial or deep regions were detected, except for type 2x fiber fraction. Together, this work highlights RTA-dependent deficits in limb function and tissue-level properties in long-term Achilles tendon and muscle healing. Copyright © 2017 Elsevier Ltd. All rights reserved.

Chronic inflammation is a feature of Achilles tendinopathy and rupture

PubMed Central

Newton, Julia; Martinez, Fernando O; Hedley, Robert; Gwilym, Stephen; Jones, Natasha; Reid, Hamish A B; Wood, Simon; Wells, Graham; Appleton, Louise; Wheway, Kim; Watkins, Bridget; Carr, Andrew Jonathan

2018-01-01

Background Recent investigation of human tissue and cells from positional tendons such as the rotator cuff has clarified the importance of inflammation in the development and progression of tendon disease. These mechanisms remain poorly understood in disease of energy-storing tendons such as the Achilles. Using tissue biopsies from patients, we investigated if inflammation is a feature of Achilles tendinopathy and rupture. Methods We studied Achilles tendon biopsies from symptomatic patients with either mid-portion tendinopathy or rupture for evidence of abnormal inflammatory signatures. Tendon-derived stromal cells from healthy hamstring and diseased Achilles were cultured to determine the effects of cytokine treatment on expression of inflammatory markers. Results Tendinopathic and ruptured Achilles highly expressed CD14+ and CD68+ cells and showed a complex inflammation signature, involving NF-κB, interferon and STAT-6 activation pathways. Interferon markers IRF1 and IRF5 were highly expressed in tendinopathic samples. Achilles ruptures showed increased PTGS2 and interleukin-8 expression. Tendinopathic and ruptured Achilles tissues expressed stromal fibroblast activation markers podoplanin and CD106. Tendon cells isolated from diseased Achilles showed increased expression of pro-inflammatory and stromal fibroblast activation markers after cytokine stimulation compared with healthy hamstring tendon cells. Conclusions Tissue and cells derived from tendinopathic and ruptured Achilles tendons show evidence of chronic (non-resolving) inflammation. The energy-storing Achilles shares common cellular and molecular inflammatory mechanisms with functionally distinct rotator cuff positional tendons. Differences seen in the profile of ruptured Achilles are likely to be attributable to a superimposed phase of acute inflammation and neo-vascularisation. Strategies that target chronic inflammation are of potential therapeutic benefit for patients with Achilles tendon disease. PMID:29118051

Mechanical, histological, and functional properties remain inferior in conservatively treated Achilles tendons in rodents: Long term evaluation

PubMed Central

Freedman, Benjamin R; Fryhofer, George W; Salka, Nabeel S; Raja, Harina A; Hillin, Cody D; Nuss, Courtney A; Farber, Daniel C; Soslowsky, Louis J

2017-01-01

Conservative treatment (non-operative) of Achilles tendon ruptures is suggested to produce equivalent capacity for return to function; however, long term results and the role of return to activity (RTA) for this treatment paradigm remain unclear. Therefore, the objective of this study was to evaluate the long term response of conservatively treated Achilles tendons in rodents with varied RTA. Sprague Dawley rats (n=32) received unilateral blunt transection of the Achilles tendon followed by randomization into groups that returned to activity after 1-week (RTA1) or 3-weeks (RTA3) of limb casting in plantarflexion, before being sacrificed at 16-weeks post-injury. Uninjured age-matched control animals were used as a control group (N=10). Limb function, passive joint mechanics, tendon properties (mechanical, histological), and muscle properties (histological, immunohistochemical) were evaluated. Results showed that although hindlimb ground reaction forces and range of motion returned to baseline levels by 16-weeks regardless of RTA, ankle stiffness remained altered. RTA1 and RTA3 groups both exhibited no differences in fatigue properties; however, the secant modulus, hysteresis, and laxity were inferior compared to uninjured age-matched control tendons. Despite these changes, tendons 16-weeks post-injury achieved secant stiffness levels of uninjured tendons. RTA1 and RTA3 groups had no differences in histological properties, but had higher cell numbers compared to control tendons. No changes in gastrocnemius fiber size or type in the superficial or deep regions were detected, except for type 2× fiber fraction. Together, this work highlights RTA-dependent deficits in limb function and tissue-level properties in long-term Achilles tendon and muscle healing. PMID:28366437

Do athletes alter their running mechanics after an Achilles tendon rupture?

PubMed

Jandacka, Daniel; Silvernail, Julia Freedman; Uchytil, Jaroslav; Zahradnik, David; Farana, Roman; Hamill, Joseph

2017-01-01

Over the past thirty years, there has been dramatic increase in incidence of Achilles tendon rupture in the athletic population. The purpose of this study was to compare the lower extremity mechanics of Achilles tendon ruptured runners with healthy controls. The participants with a past history of an Achilles tendon repair ( n  = 11) and healthy control ( n  = 11) subgroups were matched on sex, age, type of regular physical activity, mass, height, footfall pattern and lateral dominancy. Running kinetics and kinematics of the ankle, knee and hip were recorded using a high-speed motion capture system interfaced with a force platform. Achilles tendon length was measured using ultrasonography. Main outcome measures were lower extremity joint angles and moments during stance phase of running and Achilles tendon lengths. Athletes from Achilles tendon group had an affected gastro-soleus complex. Athletes with history of Achilles tendon rupture had reduced ankle range of motion during second half of the stance phase of running (Δ7.6°), an overextended knee during initial contact (Δ5.2°) and increased affected knee range of motion (Δ4.4°) during the first half of stance phase on their affected limb compared to the healthy control group. There was a 22% increase in the maximal hip joint moment on contralateral side of the Achilles tendon group compared to the healthy controls. These results suggest a compensation mechanism, relatively extended knee at initial ground contact against the deficit in the muscle-tendon complex of the triceps surae. Overextension during sporting activities may place the knee at risk for further injury. Avoidance of AT lengthening and plantarflexion strength deficit after surgery and during rehabilitation might help to manage AT rupture since these factors may be responsible for altered running kinematics.

Patellar tendon healing with platelet-rich plasma: a prospective randomized controlled trial.

PubMed

de Almeida, Adriano Marques; Demange, Marco Kawamura; Sobrado, Marcel Faraco; Rodrigues, Marcelo Bordalo; Pedrinelli, André; Hernandez, Arnaldo José

2012-06-01

The patellar tendon has limited ability to heal after harvesting its central third. Platelet-rich plasma (PRP) could improve patellar tendon healing. Adding PRP to the patellar tendon harvest site would improve donor site healing and improve clinical outcome at 6 months after anterior cruciate ligament (ACL) reconstruction with a patellar tendon graft. Randomized controlled trial; Level of evidence, 1. Twenty-seven patients were randomly divided to receive (n = 12) or not receive (n = 15) PRP in the patellar tendon harvest site during ACL reconstruction. The primary outcome was magnetic resonance imaging (MRI) assessment of patellar tendon healing (gap area) after 6 months. Secondary outcomes were questionnaires and isokinetic testing of ACL reconstruction with a patellar tendon graft comparing both groups. Patellar tendon gap area was significantly smaller in the PRP group (4.9 ± 5.3 mm(2); 95% confidence interval [CI], 1.1-8.8) than in the control group (9.4 ± 4.4 mm(2); 95% CI, 6.6-12.2; P = .046). Visual analog scale score for pain was lower in the PRP group immediately postoperatively (3.8 ± 1.0; 95% CI, 3.18-4.49) than in the control group (5.1 ± 1.4; 95% CI, 4.24-5.90; P = .02). There were no differences after 6 months in questionnaire and isokinetic testing results comparing both groups. We showed that PRP had a positive effect on patellar tendon harvest site healing on MRI after 6 months and also reduced pain in the immediate postoperative period. Questionnaire and isokinetic testing results were not different between the groups at 6 months.

Achilles Tendonitis

MedlinePlus

... almost impossible. Achilles tendonitis is a very common running injury. But it can also affect basketball players, dancers, ... Proximal Biceps Tendonitis Safety Tips: Basketball Safety Tips: Running Repetitive Stress Injuries Sports and Exercise Safety Dealing With Sports Injuries ...

Re-revision of a patellar tendon rupture in a young professional martial arts athlete.

PubMed

Vadalà, A; Iorio, R; Bonifazi, A M; Bolle, G; Ferretti, A

2012-09-01

A 27-year-old professional martial arts athlete experienced recurrent right knee patellar tendon rupture on three occasions. He underwent two operations for complete patellar tendon rupture: an end-to-end tenorrhaphy the first time, and revision with a bone-patellar-tendon (BPT) allograft. After the third episode, he was referred to our department, where we performed a surgical reconstruction with the use of hamstring pro-patellar tendon, in a figure-of-eight configuration, followed by a careful rehabilitation protocol. Clinical and radiological follow-ups were realized at 1, 3, and 6 months and 1 and 2 years postop, with an accurate physical examination, the use of recognized international outcome scores, and radiograph and MRI studies. As far as we know, this is the first paper to report a re-revision of a patellar tendon rupture.

The anteromedial approach to the psoas tendon in patients with cerebral palsy

PubMed Central

Poonnoose, Pradeep M.; Palocaren, Thomas

2007-01-01

Purpose Release of the psoas tendon for flexion deformity of the hip in children with cerebral palsy has traditionally been performed at the pelvic brim, lateral to the neurovascular bundle, or at its insertion into the lesser trochanter. As the psoas tendon is lateral to the pectineus, the traditional exposure of the tendon through an approach medial to the pectineus is limited by the extent to which the pectineus can be retracted proximally. Technical note We describe the use of the anteromedial approach used for the developmentally dislocated hip to expose the psoas tendon between the pectineus and the neurovascular bundle. This provides a much better visualisation of the tendon as it crosses the superior pubic ramus to its insertion. The use of this approach has not been described in cerebral palsy. PMID:19308518

[Conservative functional treatment of Achilles tendon ruptures].

PubMed

Hüfner, T; Gaulke, R; Imrecke, J; Krettek, C; Stübig, T

2010-09-01

The conservative functional treatment of Achilles tendon ruptures has developed further over the last 20 years and is basically possible for 60-80% of patients. The treatment leads to success if the indications obtained by dynamic sonography are correctly interpreted (adaptation of the tendon ends up to 20 degrees plantar flexion), if the patient presents sufficient compliance and the physiotherapy is increasingly intensified depending on tendon healing. Modern ortheses allow an increased equinus position and therefore improved protection of the healing tendon. If these factors are present a relatively low re-rupture rate of only 7% can be achieved. The decisive advantage of conservative functional therapy is the avoidance of specific operative risks, such as infection and injury to the sural nerve. After removal of the orthesis the tendon should continue to be modeled using shoe insoles and raised heels.

Marked pathological changes proximal and distal to the site of rupture in acute Achilles tendon ruptures.

PubMed

Maffulli, Nicola; Longo, Umile Giuseppe; Maffulli, Gayle D; Rabitti, Carla; Khanna, Anil; Denaro, Vincenzo

2011-04-01

A laboratory study was performed to evaluate the histopathological features of the macroscopically intact portion of the Achilles tendon in patients undergoing surgery for an acute rupture of the Achilles tendon. Tendon samples were harvested from 29 individuals (21 men, 8 women; mean age: 46 ± 12) who underwent repair of an Achilles tendon tear tear, and from 11 male patients who died of cardiovascular events (mean age: 61). Three pieces of tendon were harvested: at the rupture site, 4 cm proximal to the site of rupture, 1 cm proximal to the insertion of the Achilles tendon on the calcaneum. Slides were assessed using a semiquantitative grading scale assessing fiber structure and arrangement, rounding of the nuclei, regional variations in cellularity, increased vascularity, decreased collagen stainability, and hyalinization. Intra-observer reliability of the subscore readings was calculated. The pathological features were significantly more pronounced in the samples taken from the site of rupture than in the samples taken proximally and distal to it (0.008 < P < 0.01). There were no significant differences in the mean pathologic sum-scores in the samples taken proximally and distal to the site of rupture. Unruptured Achilles tendons, even at an advanced age, and ruptured Achilles tendons are clearly part of two distinct populations, with the latter demonstrating histopathological evidence of failed healing response even in areas macroscopically normal.

Does the adolescent patellar tendon respond to 5 days of cumulative load during a volleyball tournament?

PubMed

van Ark, M; Docking, S I; van den Akker-Scheek, I; Rudavsky, A; Rio, E; Zwerver, J; Cook, J L

2016-02-01

Patellar tendinopathy (jumper's knee) has a high prevalence in jumping athletes. Excessive load on the patellar tendon through high volumes of training and competition is an important risk factor. Structural changes in the tendon are related to a higher risk of developing patellar tendinopathy. The critical tendon load that affects tendon structure is unknown. The aim of this study was to investigate patellar tendon structure on each day of a 5-day volleyball tournament in an adolescent population (16-18 years). The right patellar tendon of 41 players in the Australian Volleyball Schools Cup was scanned with ultrasound tissue characterization (UTC) on every day of the tournament (Monday to Friday). UTC can quantify structure of a tendon into four echo types based on the stability of the echo pattern. Generalized estimating equations (GEE) were used to test for change of echo type I and II over the tournament days. Participants played between eight and nine matches during the tournament. GEE analysis showed no significant change of echo type percentages of echo type I (Wald chi-square = 4.603, d.f. = 4, P = 0.331) and echo type II (Wald chi-square = 6.070, d.f. = 4, P = 0.194) over time. This study shows that patellar tendon structure of 16-18-year-old volleyball players is not affected during 5 days of cumulative loading during a volleyball tournament. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Prevalence of triceps tendon tears on MRI of the elbow and clinical correlation.

PubMed

Koplas, Monica C; Schneider, Erika; Sundaram, Murali

2011-05-01

Triceps tendon injuries are reported to be very rare. To our knowledge, there have been no studies describing its prevalence or injury patterns on MR imaging. The purpose of this retrospective study was to determine the prevalence and patterns of triceps injuries based on a large series of consecutive MR examinations. Clinical correlation was obtained. From 801 consecutive elbow MR examinations over a 15-year period, 28 patients with 30 triceps tendon injuries were identified and graded as partial tendon tear and complete tendon tear. The patients' medical records were reviewed to determine age, gender, cause of tears, and management. The prevalence of triceps tendon injuries was 3.8%. There were 5 women and 23 men with partial or complete tears (mean age: 46.6 years; range: 2.7 to 75.1 years). The most common injury was partial tear, found in 18 patients. There were 10 patients with 12 complete tears (2 had re-torn following surgical repair). A tear was suspected in 12 out 28 (43%) patients prior to the MRI. The most common presenting symptom was pain. The most common cause was athletic injury (8 patients [29%], including weightlifting [2 patients]). Tendon tear was found to be a complication of infection in 6 patients, and in 3 patients the tears were a complication of steroid use. Thirteen tendon tears were surgically repaired (8 of these were complete tears). Triceps tendon injury is not as rare as commonly reported and may often be clinically underdiagnosed.

New Developments Are Improving Flexor Tendon Repair.

PubMed

Tang, Jin Bo

2018-06-01

New developments in primary tendon repair in recent decades include stronger core tendon repair techniques, judicious and adequate venting of critical pulleys, followed by a combination of passive and active digital flexion and extension. During repair, core sutures over the tendon should have sufficient suture purchase (no shorter than 0.7 to 1 cm) in each tendon end and must be sufficiently tensioned to resist loosening and gap formation between tendon ends. Slight or even modest bulkiness in the tendon substance at the repair site is not harmful, although marked bulkiness should always be avoided. To expose the tendon ends and reduce restriction to tendon gliding, the longest annular pulley in the fingers (i.e., the A2 pulley) can be vented partially with an incision over its distal or proximal sheath no longer than 1.5 to 2 cm; the annular pulley over the middle phalanx (i.e., the A4 pulley) can be vented entirely. Surgeons have not observed adverse effects on hand function after judicious and limited venting. The digital extension-flexion test to check the quality of the repair during surgery has become increasingly routine. A wide-awake surgical setting allows patient to actively move the digits. After surgery, surgeons and therapists protect patients with a short splint and flexible wrist positioning, and are now moving toward out-of-splint freer early active motion. Improved outcomes have been reported over the past decade with minimal or no rupture during postoperative active motion, along with lower rates of tenolysis.

Early changes in Achilles tendon behaviour in vivo following downhill backwards walking.

PubMed

Joseph, C W; Bradshaw, E J; Furness, T P; Kemp, J; Clark, R A

2016-01-01

Downhill backwards walking causes repeated, cyclical loading of the muscle-tendon unit. The effect this type of repeated loading has on the mechanical behaviour of the Achilles tendon is presently unknown. This study aimed to investigate the biomechanical response of the Achilles tendon aponeurosis complex following a downhill backwards walking protocol. Twenty active males (age: 22.3 ± 3.0 years; mass: 74.7 ± 5.6 kg; height: 1.8 ± 0.7 m) performed 60 min of downhill (8.5°), backwards walking on a treadmill at -0.67 m · s(-1). Data were collected before, immediately post, and 24-, 48- and 168-h post-downhill backwards walking. Achilles tendon aponeurosis elongation, strain and stiffness were measured using ultrasonography. Muscle force decreased immediately post-downhill backward walking (P = 0.019). There were increases in Achilles tendon aponeurosis stiffness at 24-h post-downhill backward walking (307 ± 179.6 N · mm(-1), P = 0.004), and decreases in Achilles tendon aponeurosis strain during maximum voluntary contraction at 24 (3.8 ± 1.7%, P = 0.008) and 48 h (3.9 ± 1.8%, P = 0.002) post. Repeated cyclical loading of downhill backwards walking affects the behaviour of the muscle-tendon unit, most likely by altering muscle compliance, and these changes result in tendon stiffness increases.

The Effects of Platelet-Rich Plasma on Bone Marrow Stromal Cell Transplants for Tendon Healing In Vitro

PubMed Central

Morizaki, Yutaka; Zhao, Chunfeng; An, Kai-Nan; Amadio, Peter C.

2010-01-01

Purpose In this study we investigated the effect of platelet-rich plasma (PRP) and bone-marrow derived stromal cell (BMSC)-seeded interposition in an in vitro canine tendon repair model. Methods Bone marrow, peripheral blood, and tendons were harvested from mixed breed dogs. BMSC were cultured and passaged from adherent cells of bone marrow suspension. PRP was purified from peripheral blood using a commercial kit. 192 flexor digitorum profundus tendons were used for the study. Tendons repaired with a simple suture were used as a control group. In treatment groups, a collagen gel patch was interposed at the tendon repair site prior to suture. There were three treatment groups according to the type of collagen patch; a patch with PRP, a patch with BMSC, and a patch with PRP and BMSC. The repaired tendons were evaluated by biomechanical testing and by histological survey after 2 and 4 weeks in tissue culture. To evaluate viability, cells were labeled with PKH26 and surveyed under confocal microscopy after culture. Results The maximum breaking strength and stiffness of the healing tendons with the BMSC-seeded PRP patch was significantly higher than the healing tendons without a patch or with a cell-seeded patch (p<0.02). Viable BMSC were present at both 2 and 4 weeks. Conclusions PRP enhanced the effect of BMSC-seeded collagen gel interposition in this in vitro model. Based on these results we now plan to investigate this effect in vivo. PMID:20951509

Repair of insertional achilles tendinosis with a bone-quadriceps tendon graft.

PubMed

Philippot, Rémi; Wegrzyn, Julien; Grosclaude, Sophie; Besse, Jean Luc

2010-09-01

While conservative treatment may be successful in most cases, partial rupture at the calcaneal insertion point is a significant concern with insertional Achilles tendinopathy. We report on the outcomes of a surgical technique for Achilles tendon augmentation using a bone-tendon graft harvested from the knee extensor system. Our retrospective case series includes 25 surgical procedures performed in 24 patients, 19 males and five females, with a mean age of 47 (range, 30 to 59) years, 18 of whom were athletes. The mean followup period was 52 (range, 12 to 156) months. All patients underwent MRI examination prior to surgery which showed partial Achilles tendon rupture. The Achilles tendon was debrided through a posterolateral approach. The bone-quadriceps tendon graft was harvested, then the bone plug of the graft was inserted into a blind tunnel drilled into the calcaneus and fixed with an interference screw. The fibers of the quadriceps tendon were sutured to the residual part of the Achilles tendon with the foot at an angle of 90 degrees. Patients were able to resume their sporting activity after an average of 6.7 months. At last followup examination, physical activity was scored 5.2 on the 10-point Tegner Scale; the mean AOFAS score was 98.4. MRI examination showed good graft integration 1 year postoperatively. The bone-quadriceps tendon grafting technique was a good alternative for the insertional Achilles lesions with partial detachment which we felt required augmentation.

Smad8/BMP2-engineered mesenchymal stem cells induce accelerated recovery of the biomechanical properties of the Achilles tendon.

PubMed

Pelled, Gadi; Snedeker, Jess G; Ben-Arav, Ayelet; Rigozzi, Samuela; Zilberman, Yoram; Kimelman-Bleich, Nadav; Gazit, Zulma; Müller, Ralph; Gazit, Dan

2012-12-01

Tendon tissue regeneration is an important goal for orthopedic medicine. We hypothesized that implantation of Smad8/BMP2-engineered MSCs in a full-thickness defect of the Achilles tendon (AT) would induce regeneration of tissue with improved biomechanical properties. A 2 mm defect was created in the distal region of murine ATs. The injured tendons were then sutured together or given implants of genetically engineered MSCs (GE group), non-engineered MSCs (CH3 group), or fibrin gel containing no cells (FG group). Three weeks later the mice were killed, and their healing tendons were excised and processed for histological or biomechanical analysis. A biomechanical analysis showed that tendons that received implants of genetically engineered MSCs had the highest effective stiffness (>70% greater than natural healing, p < 0.001) and elastic modulus. There were no significant differences in either ultimate load or maximum stress among the treatment groups. Histological analysis revealed a tendon-like structure with elongated cells mainly in the GE group. ATs that had been implanted with Smad8/BMP2-engineered stem cells displayed a better material distribution and functional recovery than control groups. While additional study is required to determine long-term effects of GE MSCs on tendon healing, we conclude that genetically engineered MSCs may be a promising therapeutic tool for accelerating short-term functional recovery in the treatment of tendon injuries. Copyright © 2012 Orthopaedic Research Society.

Quantification of Posterior Ankle Exposure Through an Achilles Tendon-Splitting Versus Posterolateral Approach

DTIC Science & Technology

2012-10-01

Ankle Exposure Through an Achilles Tendon - Splitting Versus Posterolateral Approach Jeanne C. Patzkowski, MD1; Kevin L. Kirk, DO1; Justin D. Orr, MD2...surgical exposure to the posterior ankle for trauma and reconstruction is a source of debate. We hypothesized that the Achilles tendon -splitting approach...fresh-frozen cadavers. Achilles tendon - splitting and posterolateral approaches were performed using a randomized crossover design for surgical

Endoscopy-assisted percutaneous repair of acute Achilles tendon tears.

PubMed

Chiu, Chih-Hao; Yeh, Wen-Lin; Tsai, Min-Chien; Chang, Shih-Sheng; Hsu, Kuo-Yao; Chan, Yi-Sheng

2013-08-01

We developed a technique for endoscopy-assisted percutaneous repair of acute Achilles tendon tears. Nineteen patients with acute Achilles tendon tears were prospectively recruited into the study. All patients (18 male, 1 female) had sports-related injuries. Preoperative diagnosis was made from patient history, physical examination, and sonography. The average patient age was 38.7 years, and follow-up averaged 24 months. All patients received endoscopy-assisted percutaneous Achilles tendon repair with modified Bunnell sutures passed by bird beak and No. 5 Ethibond under direct visualization using 4.0-mm arthroscopy. Results were evaluated by physical examination, sonography, and magnetic resonance imaging (MRI). All 19 patients achieved tendon healing. All patients were evaluated by sonography, and the tendons of 16 patients were imaged using MRI to evaluate the extent of healing. Final dorsiflexion was 16 degrees and plantar flexion 26 degrees, and 95% of the patients (18/19) returned to their previous level of sporting activity. One patient developed a superficial infection, and 2 patients had postoperative sural nerve injury with numbness for 1 month. There were no other major complications. Endoscopy-assisted percutaneous repair of the Achilles tendon allowed good tendon healing and return to sports at 6 months. Sural nerve injury during surgery was a potential complication of this procedure. Level IV, retrospective case series.

Augmented Repair of an Achilles Tendon Rupture Using the Flexor Digitorum Lateralis Tendon in a Toy Poodle.

PubMed

Katayama, Masaaki

2016-11-01

To report appositional augmentation of Achilles tendon rupture in a toy breed dog with an intact flexor digitorum lateralis (FDL) muscle tendon. Clinical case report. Two-year-old spayed female Toy Poodle with Achilles tendon rupture. The Achilles tendon was accidentally ruptured by hair clippers during grooming. The dog demonstrated a plantigrade stance without digital flexion of the right hind limb. The ruptured gastrocnemius and superficial digital flexor tendons were sutured to their respective cut ends using a simple locking loop pattern under a surgical microscope. The repair site was appositionally augmented by the caudally retracted intact FDL. An aluminum splint was applied on the plantar aspect to immobilize the tarsal joint for the first 2 weeks, after which a soft bandage was applied for another 2 weeks. At the 7 month follow-up no lameness was detected during walking and no complications associated with decreased FDL function such as digital contracture were observed. The range of motion of the tarsal joint had improved and could be flexed to ∼60° and extended fully. Use of the FDL is feasible for augmenting Achilles tendon repair in toy breed dogs. © Copyright 2016 by The American College of Veterinary Surgeons.

[Tendinopathy in rheumatic diseases].

PubMed

Henniger, M; Rehart, S

2017-03-01

Involvement of tendons and tendon sheaths is frequently found in the most common inflammatory systemic diseases, rheumatoid arthritis and spondyloarthritis. In rheumatoid arthritis tendon manifestations occur as tenosynovitis, with swelling and pain of the tendons mainly on the hands and feet. In spondyloarthritis the involvement of tendons presents as enthesitis with pain and swelling directly at the attachment points of tendons to the bony structures and more commonly in the lower extremities. Pathological alterations of tendons can be normally visualized by sonography and only sometimes with magnetic resonance imaging (MRI) or scintigraphy. Furthermore, it is important for diagnostics and effective therapy to detect all joints involved by means of clinical, sonographic and radiological examination as well as laboratory parameters of inflammation, antibody serology (e.g. anti-CCP antibodies) and HLA-B27. The histopathological alterations of tendinopathy in rheumatic diseases differ from degenerative/posttraumatic tendinopathy in their expression of the changes; however, a clear differentiation of the different rheumatic inflammatory systemic diseases is histopathologically not possible. Therapeutically, systemic medication is the most important part of treatment in rheumatic diseases. Local therapeutic measures can be employed in the treatment of tenosynovitis and enthesitis. In the case of failure or lack of efficacy of the medication and conservative therapy, tenosynovectomy is performed for persistent tenosynovitis and reconstructive surgical procedures are necessary for tendon ruptures.

Differences between the Cell Populations from the Peritenon and the Tendon Core with Regard to Their Potential Implication in Tendon Repair

PubMed Central

Cadby, Jennifer A.; Buehler, Evelyne; Godbout, Charles; van Weeren, P. René; Snedeker, Jess G.

2014-01-01

The role of intrinsic and extrinsic healing in injured tendons is still debated. In this study, we characterized cell plasticity, proliferative capacity, and migration characteristics as proxy measures of healing potential in cells derived from the peritenon (extrinsic healing) and compared these to cells from the tendon core (intrinsic healing). Both cell populations were extracted from horse superficial digital flexor tendon and characterized for tenogenic and matrix remodeling markers as well as for rates of migration and replication. Furthermore, colony-forming unit assays, multipotency assays, and real-time quantitative polymerase chain reaction analyses of markers of osteogenic and adipogenic differentiation after culture in induction media were performed. Finally, cellular capacity for differentiation towards a myofibroblastic phenotype was assessed. Our results demonstrate that both tendon- and peritenon-derived cell populations are capable of adipogenic and osteogenic differentiation, with higher expression of progenitor cell markers in peritenon cells. Cells from the peritenon also migrated faster, replicate more quickly, and show higher differentiation potential toward a myofibroblastic phenotype when compared to cells from the tendon core. Based on these data, we suggest that cells from the peritenon have substantial potential to influence tendon-healing outcome, warranting further scrutiny of their role. PMID:24651449

Three dimensional microstructural network of elastin, collagen, and cells in Achilles tendons.

PubMed

Pang, Xin; Wu, Jian-Ping; Allison, Garry T; Xu, Jiake; Rubenson, Jonas; Zheng, Ming-Hao; Lloyd, David G; Gardiner, Bruce; Wang, Allan; Kirk, Thomas Brett

2017-06-01

Similar to most biological tissues, the biomechanical, and functional characteristics of the Achilles tendon are closely related to its composition and microstructure. It is commonly reported that type I collagen is the predominant component of tendons and is mainly responsible for the tissue's function. Although elastin has been found in varying proportions in other connective tissues, previous studies report that tendons contain very small quantities of elastin. However, the morphology and the microstructural relationship among the elastic fibres, collagen, and cells in tendon tissue have not been well examined. We hypothesize the elastic fibres, as another fibrillar component in the extracellular matrix, have a unique role in mechanical function and microstructural arrangement in Achilles tendons. It has been shown that elastic fibres present a close connection with the tenocytes. The close relationship of the three components has been revealed as a distinct, integrated and complex microstructural network. Notably, a "spiral" structure within fibril bundles in Achilles tendons was observed in some samples in specialized regions. This study substantiates the hierarchical system of the spatial microstructure of tendon, including the mapping of collagen, elastin and tenocytes, with 3-dimensional confocal images. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1203-1214, 2017. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Tendon basic science: Development, repair, regeneration, and healing.

PubMed

Andarawis-Puri, Nelly; Flatow, Evan L; Soslowsky, Louis J

2015-06-01

Tendinopathy and tendon rupture are common and disabling musculoskeletal conditions. Despite the prevalence of these injuries, a limited number of investigators are conducting fundamental, basic science studies focused on understanding processes governing tendinopathies and tendon healing. Development of effective therapeutics is hindered by the lack of fundamental guiding data on the biology of tendon development, signal transduction, mechanotransduction, and basic mechanisms underlying tendon pathogenesis and healing. To propel much needed progress, the New Frontiers in Tendon Research Conference, co-sponsored by NIAMS/NIH, the Orthopaedic Research Society, and the Icahn School of Medicine at Mount Sinai, was held to promote exchange of ideas between tendon researchers and basic science experts from outside the tendon field. Discussed research areas that are underdeveloped and represent major hurdles to the progress of the field will be presented in this review. To address some of these outstanding questions, conference discussions and breakout sessions focused on six topic areas (Cell Biology and Mechanics, Functional Extracellular Matrix, Development, Mechano-biology, Scarless Healing, and Mechanisms of Injury and Repair), which are reviewed in this special issue and briefly presented in this review. Review articles in this special issue summarize the progress in the field and identify essential new research directions. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

The mechanism for efficacy of eccentric loading in Achilles tendon injury; an in vivo study in humans.

PubMed

Rees, J D; Lichtwark, G A; Wolman, R L; Wilson, A M

2008-10-01

Degenerative disorders of tendons present an enormous clinical challenge. They are extremely common, prone to recur and existing medical and surgical treatments are generally unsatisfactory. Recently eccentric, but not concentric, exercises have been shown to be highly effective in managing tendinopathy of the Achilles (and other) tendons. The mechanism for the efficacy of these exercises is unknown although it has been speculated that forces generated during eccentric loading are of a greater magnitude. Our objective was to determine the mechanism for the beneficial effect of eccentric exercise in Achilles tendinopathy. Seven healthy volunteers performed eccentric and concentric loading exercises for the Achilles tendon. Tendon force and length changes were determined using a combination of motion analysis, force plate data and real-time ultrasound. There was no significant difference in peak tendon force or tendon length change when comparing eccentric with concentric exercises. However, high-frequency oscillations in tendon force occurred in all subjects during eccentric exercises but were rare in concentric exercises (P < 0.0001). These oscillations provide a mechanism to explain the therapeutic benefit of eccentric loading in Achilles tendinopathy and parallels recent evidence from bone remodelling, where the frequency of the loading cycles is of more significance than the absolute magnitude of the force.

The energetic benefits of tendon springs in running: is the reduction of muscle work important?

PubMed

Holt, Natalie C; Roberts, Thomas J; Askew, Graham N

2014-12-15

The distal muscle-tendon units of cursorial species are commonly composed of short muscle fibres and long, compliant tendons. It is assumed that the ability of these tendons to store and return mechanical energy over the course of a stride, thus avoiding the cyclic absorption and regeneration of mechanical energy by active muscle, offers some metabolic energy savings during running. However, this assumption has not been tested directly. We used muscle ergometry and myothermic measurements to determine the cost of force production in muscles acting isometrically, as they could if mechanical energy was stored and returned by tendon, and undergoing active stretch-shorten cycles, as they would if mechanical energy was absorbed and regenerated by muscle. We found no detectable difference in the cost of force production in isometric cycles compared with stretch-shorten cycles. This result suggests that replacing muscle stretch-shorten work with tendon elastic energy storage and recovery does not reduce the cost of force production. This calls into question the assumption that reduction of muscle work drove the evolution of long distal tendons. We propose that the energetic benefits of tendons are derived primarily from their effect on muscle and limb architecture rather than their ability to reduce the cyclic work of muscle. © 2014. Published by The Company of Biologists Ltd.

Doppler ultrasound-based measurement of tendon velocity and displacement for application toward detecting user-intended motion.

PubMed

Stegman, Kelly J; Park, Edward J; Dechev, Nikolai

2012-07-01

The motivation of this research is to non-invasively monitor the wrist tendon's displacement and velocity, for purposes of controlling a prosthetic device. This feasibility study aims to determine if the proposed technique using Doppler ultrasound is able to accurately estimate the tendon's instantaneous velocity and displacement. This study is conducted with a tendon mimicking experiment consisting of two different materials: a commercial ultrasound scanner, and a reference linear motion stage set-up. Audio-based output signals are acquired from the ultrasound scanner, and are processed with our proposed Fourier technique to obtain the tendon's velocity and displacement estimates. We then compare our estimates to an external reference system, and also to the ultrasound scanner's own estimates based on its proprietary software. The proposed tendon motion estimation method has been shown to be repeatable, effective and accurate in comparison to the external reference system, and is generally more accurate than the scanner's own estimates. After establishing this feasibility study, future testing will include cadaver-based studies to test the technique on the human arm tendon anatomy, and later on live human test subjects in order to further refine the proposed method for the novel purpose of detecting user-intended tendon motion for controlling wearable prosthetic devices.

The energetic benefits of tendon springs in running: is the reduction of muscle work important?

PubMed Central

Holt, Natalie C.; Roberts, Thomas J.; Askew, Graham N.

2014-01-01

The distal muscle-tendon units of cursorial species are commonly composed of short muscle fibres and long, compliant tendons. It is assumed that the ability of these tendons to store and return mechanical energy over the course of a stride, thus avoiding the cyclic absorption and regeneration of mechanical energy by active muscle, offers some metabolic energy savings during running. However, this assumption has not been tested directly. We used muscle ergometry and myothermic measurements to determine the cost of force production in muscles acting isometrically, as they could if mechanical energy was stored and returned by tendon, and undergoing active stretch–shorten cycles, as they would if mechanical energy was absorbed and regenerated by muscle. We found no detectable difference in the cost of force production in isometric cycles compared with stretch–shorten cycles. This result suggests that replacing muscle stretch–shorten work with tendon elastic energy storage and recovery does not reduce the cost of force production. This calls into question the assumption that reduction of muscle work drove the evolution of long distal tendons. We propose that the energetic benefits of tendons are derived primarily from their effect on muscle and limb architecture rather than their ability to reduce the cyclic work of muscle. PMID:25394624

Nandrolone decanoate and load increase remodeling and strength in human supraspinatus bioartificial tendons.

PubMed

Triantafillopoulos, Ioannis K; Banes, Albert J; Bowman, Karl F; Maloney, Melissa; Garrett, William E; Karas, Spero G

2004-06-01

To date, no studies document the effect of anabolic steroids on rotator cuff tendons. Controlled laboratory study. Anabolic steroids enhance remodeling and improve the biomechanical properties of bioartificially engineered human supraspinatus tendons. Bioartificial tendons were treated with either nandrolone decanoate (nonload, steroid, n = 18), loading (load, nonsteroid, n = 18), or both (load, steroid, n = 18). A control group received no treatment (nonload, nonsteroid [NLNS], n = 18). Bioartificial tendons' remodeling was assessed by daily scanning, cytoskeletal organization by staining, matrix metalloproteinase-3 levels by ELISA assay, and biomechanical properties by load-to-failure testing. The load, steroid group showed the greatest remodeling and the best organized actin cytoskeleton. Matrix metallo-proteinase-3 levels in the load, steroid group were greater than those of the nonload, nonsteroid group (P <.05). Ultimate stress and ultimate strain in the load, steroid group were greater than those of the nonload, nonsteroid and nonload, steroid groups (P <.05). The strain energy density in the load, steroid group was greater when compared to other groups (P <.05). Nandrolone decanoate and load acted synergistically to increase matrix remodeling and biomechanical properties of bioartificial tendons. Data suggest anabolic steroids may enhance production of bioartificial tendons and rotator cuff tendon healing in vitro. More research is necessary before such clinical use is recommended.

Heterotopic mineralization (ossification or calcification) in tendinopathy or following surgical tendon trauma

PubMed Central

O'Brien, Etienne J O; Frank, Cyril B; Shrive, Nigel G; Hallgrímsson, Benedikt; Hart, David A

2012-01-01

Heterotopic tendon mineralization (ossification or calcification), which may be a feature of tendinopathy or which may develop following surgical trauma (repair or graft harvest), has not received much attention. The purpose of this article is to review the prevalence, mechanisms and consequences of heterotopic tendon mineralization and to identify the gaps in our current understanding. We focus on endochondral heterotopic ossification and draw on knowledge of the mechanisms of this process in other tissues and conditions. Finally, we introduce a novel murine Achilles tendon needle injury model, which will enable us to further study the mechanisms and biomechanical consequences of tendon mineralization. PMID:22974213

The distal biceps tendon.

PubMed

Schmidt, Christopher C; Jarrett, Claudius D; Brown, Brandon T

2013-04-01

Distal biceps tendon ruptures continue to be an important injury seen and treated by upper extremity surgeons. Since the mid-1980s, the emphasis has been placed on techniques that limit complications or improve initial tendon-to-bone fixation strength. Recently, basic science research has expanded the knowledge base regarding the biceps tendon structure, footprint anatomy, and biomechanics. Clinical data have further delineated the results of conservative and surgical management of both partial and complete tears in acute or chronic states. The current literature on the distal biceps tendon is described in detail. Copyright © 2013 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

The V-Shaped Distal Triceps Tendon Repair: A Comparative Biomechanical Analysis.

PubMed

Scheiderer, Bastian; Imhoff, Florian B; Morikawa, Daichi; Lacheta, Lucca; Obopilwe, Elifho; Cote, Mark P; Imhoff, Andreas B; Mazzocca, Augustus D; Siebenlist, Sebastian

2018-05-01

Restoring footprint anatomy, minimizing gap formation, and maximizing the strength of distal triceps tendon repairs are essential factors for a successful healing process and return to sport. The novel V-shaped distal triceps tendon repair technique with unicortical button fixation closely restores footprint anatomy, provides minimal gap formation and high ultimate failure load, and minimizes iatrogenic fracture risk in acute/subacute distal triceps tendon tears. Controlled laboratory study. Twenty-four cadaveric elbows (mean ± SD age, 66 ± 5 years) were randomly assigned to 1 of 3 repair groups: the transosseous cruciate repair technique (gold standard), the knotless suture-bridge repair technique, and the V-shaped distal triceps tendon repair technique. Anatomic measurements of the central triceps tendon footprint were obtained in all specimens with a 3-dimensional digitizer before and after the repair. Cyclic loading was performed for a total of 1500 cycles at a rate of 0.25 Hz, pulling in the direction of the triceps. Displacements were measured on the medial and lateral tendon sites with 2 differential variable reluctance transducers. Load to failure and construct failure mode were recorded. The mean triceps bony insertion area was 399.05 ± 81.23 mm 2 . The transosseous cruciate repair technique restored 36.6% ± 16.8% of the native tendon insertion area, which was significantly different when compared with the knotless suture-bridge repair technique (85.2% ± 14.8%, P = .001) and the V-shaped distal triceps tendon repair technique (88.9% ± 14.8%, P = .002). Mean displacement showed no significant difference between the V-shaped distal triceps tendon repair technique (medial side, 0.75 ± 0.56 mm; lateral side, 0.99 ± 0.59 mm) and the knotless suture-bridge repair technique (1.61 ± 0.97 mm and 1.29 ± 0.8 mm) but significance between the V-shaped distal triceps tendon repair technique and the transosseous cruciate repair technique (4.91 ± 1.12 mm and 5.78 ± 0.9 mm, P < .001). Mean peak failure load of the V-shaped distal triceps tendon repair technique (732.1 ± 156.0 N) was significantly higher than that of the knotless suture-bridge repair technique (505.4 ± 173.9 N, P = .011) and the transosseous cruciate repair technique (281.1 ± 74.8 N, P < .001). Mechanism of failure differed among the 3 repairs, with the only olecranon fracture occurring in the knotless suture-bridge repair technique at the level of the lateral row suture anchors. At time zero, the V-shaped distal triceps tendon repair technique and the knotless suture-bridge repair technique both provided anatomic footprint coverage. Ultimate load to failure was highest for the V-shaped distal triceps tendon repair technique, while gap formation was different only in comparison with the transosseous cruciate repair technique. The V-shaped distal triceps tendon repair technique provides an alternative procedure to other established repairs for acute/subacute distal triceps tendon ruptures. The reduced repair site motion of the V-shaped distal triceps tendon repair technique and the knotless suture-bridge repair technique at the time of surgery may allow a more aggressive rehabilitation program in the early postoperative period.

Diclofenac Patch for Treatment of Mild to Moderate Tendonitis or Bursitis

ClinicalTrials.gov

2008-08-05

Rotator Cuff Tendonitis; Bicipital Tendonitis; Subdeltoid Bursitis of the Shoulder; Subacromial Bursitis of the Shoulder; Medial Epicondylitis of the Elbow; Lateral Epicondylitis of the Elbow; DeQuervain's Tenosynovitis of the Wrist

Partial achilles tendon rupture presenting with giant hematoma; MRI findings of 4 year follow up.

PubMed

Sarsilmaz, Aysegul; Varer, Makbule; Coskun, Gulten; Apaydın, Melda; Oyar, Orhan

2011-12-01

In the young population, spontaneous rupture of Achilles tendon is very rare. The big hematoma is also rare finding of the Achilles tendon partial rupture. It is usually seen with complete rupture. We presented imaging findings of 4 years follow up of the spontaneous partial rupture of Achilles tendon presenting with giant expanding hematoma and mimicking complete rupture radiologically. We discussed the alterations of tendon signal intensity and result of conservative therapy after partial rupture with big hematoma in the long term. A 29 year-old man, applied with pain and swelling in the retrocalcaneal region of left ankle. He did not have chronic metabolic disease. He was not active in physical activities. X-ray radiograms were normal. At magnetic resonance images (MRI), there was an intratendinous big hematoma, subcutanous fat planes were edematous around tendon. The diagnosis was partial rupture and giant hematoma. Hematoma was drained. The conservative treatment was applied and his complaints disappeared. After treatment, approximately 4 years later, control MRI showed thickened and hypointense tendon in all images. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Extensor Tendon Injuries and Repairs in the Hand

PubMed Central

Kontor, J. A.

1982-01-01

Due to their superficial course, the extensor tendons are frequently lacerated over the dorsum of the hand and fingers. Excellent functional results are obtained in repairs of simple tendon lacerations. ‘Open’ mallet lacerations over the distal IP joint or involving the central extensor slip over the proximal IP joint require more precise suturing methods. More proximal extensor tendon divisions near the wrist involve dissection of the retracted finger extensors or long thumb extensor in the distal forearm and more formal tendon repairs, including a possible tendon transfer to the thumb. ‘Closed injuries’, with varying degrees of extensor tendon disruption, occur at three main sites. The mallet injury at the DIP joint and the boutonnière deformity over the PIP joint are sometimes recognized late, but respond to conservative splinting for a minimum of four weeks with guarded motion avoiding secondary stiffening of the remaining small joints of the hand. Surgery of closed injuries most frequently involves the intra-articular traction fracture type of mallet deformities in which the DIP joint has taken the brunt of the injury. PMID:21286174

Tendon rupture associated with excessive smartphone gaming.

PubMed

Gilman, Luke; Cage, Dori N; Horn, Adam; Bishop, Frank; Klam, Warren P; Doan, Andrew P

2015-06-01

Excessive use of smartphones has been associated with injuries. A 29-year-old, right hand-dominant man presented with chronic left thumb pain and loss of active motion from playing a Match-3 puzzle video game on his smartphone all day for 6 to 8 weeks. On physical examination, the left extensor pollicis longus tendon was not palpable, and no tendon motion was noted with wrist tenodesis. The thumb metacarpophalangeal range of motion was 10° to 80°, and thumb interphalangeal range of motion was 30° to 70°. The clinical diagnosis was rupture of the left extensor pollicis longus tendon. The patient subsequently underwent an extensor indicis proprius (1 of 2 tendons that extend the index finger) to extensor pollicis longus tendon transfer. During surgery, rupture of the extensor pollicis longus tendon was seen between the metacarpophalangeal and wrist joints. The potential for video games to reduce pain perception raises clinical and social considerations about excessive use, abuse, and addiction. Future research should consider whether pain reduction is a reason some individuals play video games excessively, manifest addiction, or sustain injuries associated with video gaming.

Arthroscopically Assisted Latissimus Dorsi Tendon Transfer in Beach-Chair Position

PubMed Central

Jermolajevas, Viktoras; Kordasiewicz, Bartlomiej

2015-01-01

Irreparable rotator cuff tears remain a surgical problem. The open technique of latissimus dorsi (LD) tendon transfer to “replace” the irreparable rotator cuff is already well known. The aim of this article is to present a modified arthroscopically assisted LD tendon transfer technique. This technique was adopted to operate on patients in the beach-chair position with several improvements in tendon harvesting and fixation. It can be divided into 6 steps, and only 1 step—LD muscle and tendon release—is performed open. The advantages of the arthroscopic procedure are sparing of the deltoid muscle, the possibility of repairing the subscapularis tendon, and the ability to visualize structures at risk while performing tendon harvesting (radial nerve) and passing into the subacromial space (axillary nerve). It is performed in a similar manner to standard rotator cuff surgery—the beach-chair position does not need any modification, and no sophisticated equipment for either the open or arthroscopic part of the procedure is necessary. Nevertheless, this is a challenging procedure and should only be attempted after training, as well as extensive practice. PMID:26759777

Conservative management of partial extensor tendon lacerations greater than half the width of the tendon in manual workers.

PubMed

Al-Qattan, Mohammad M

2015-04-01

Conservative management (without suturing or splints) of partial extensor tendon lacerations greater than half the width of the tendon has not been previously investigated. In this prospective study, a total of 45 injured tendons (with lacerations involving 55%-90% of the width of the tendon) in 39 patients were treated conservatively. Injury zones I, III, and V of the fingers; and zones I and III of the thumb were excluded. Immediate non-resistive active mobilization was initiated and continued for 4 weeks, followed by resistive exercises. Patients were allowed to go back to work after 6 weeks. There were no cases of ruptures, triggering, infection, or complex regional pain syndrome. At final follow-up (8-9 months after injury), all patients obtained full range of motion with no extension lags. All patients were able to go back to normal duties. We conclude that early active motion without the use of splints or sutures in major extensor tendon lacerations in zones II, IV, VI-VIII of the fingers; and zones II, IV, and V of the thumb is safe.

Effects of braiding on tensile properties of four-strand human hamstring tendon grafts.

PubMed

Millett, Peter J; Miller, Bruce S; Close, Matthew; Sterett, William I; Walsh, William; Hawkins, Richard J

2003-01-01

Anterior cruciate ligament reconstruction is commonly performed with autogenous hamstring tendon grafts. To ascertain the effects of braiding on ultimate tensile strength and stiffness of hamstring tendon graft. Controlled laboratory study. Sixteen fresh-frozen semitendinosus and gracilis tendons were harvested from eight matched (right and left) human cadaveric specimens. Both sets of hamstring tendons from each matched pair were doubled, creating a four-strand graft. Grafts were then randomized so that one graft from each matched pair was braided and the other remained unbraided. The diameter of each graft construct was recorded. Grafts were tested to failure on a materials testing machine. There were no significant differences in cross-sectional area before or after braiding. Fifteen of 16 tendons failed midsubstance; 1 failed at the lower clamp. Braiding reduced the initial tensile strength and stiffness of human hamstring tendon grafts in this study by 35.0% and 45.8%, respectively. Braiding may place the collagen fibers in a suboptimal orientation for loading that results in a weaker graft. We do not recommend the use of braiding if the strongest, stiffest initial graft is desired.

A systematic review of tibialis anterior tendon rupture treatments and outcomes.

PubMed

Christman-Skieller, Claudia; Merz, Michael K; Tansey, Joseph P

2015-04-01

Tibialis anterior (TA) tendon rupture is a relatively rare injury that has been documented primarily in case reports. This article is the first large systematic review of the literature on treatment techniques for subcutaneous rupture of TA tendons. Studies for review were identified through a PubMed search. Eligible studies involved cases of closed tendon rupture. Of the 87 cases in the study, 72 were treated with surgery, 15 with conservative measures. Mean age was 63.9 years (surgery group) and 72.4 years (conservative treatment group). Primary repair was used most often for newer injuries, autograft most often for older injuries. Operative repair of subcutaneous TA tendon rupture leads to successful outcomes in many patients. A surgeon who is deciding which operative technique to use for a patient should consider the age of the injury and the findings of intraoperative assessment for tendon necrosis.

Eccentric exercise: acute and chronic effects on healthy and diseased tendons.

PubMed

Kjaer, Michael; Heinemeier, Katja M

2014-06-01

Eccentric exercise can influence tendon mechanical properties and matrix protein synthesis. mRNA for collagen and regulatory factors thereof are upregulated in animal tendons, independent of muscular contraction type, supporting the view that tendon, compared with skeletal muscle, is less sensitive to differences in type and/or amount of mechanical stimulus with regard to expression of collagen, regulatory factors for collagen, and cross-link regulators. In overused (tendinopathic) human tendon, eccentric exercise training has a beneficial effect, but the mechanism by which this is elicited is unknown, and slow concentric loading appears to have similar beneficial effects. It may be that tendinopathic regions, as long as they are subjected to a certain magnitude of load at a slow speed, independent of whether this is eccentric or concentric in nature, can reestablish their normal tendon fibril alignment and cell morphology. Copyright © 2014 the American Physiological Society.

The effect of freeze-thawing on magnetic resonance imaging T2* of freshly harvested bovine patellar tendon

PubMed Central

Pownder, Sarah L.; Shah, Parina H.; Potter, Hollis G.

2015-01-01

Background Analysis of fresh specimens in research studies is ideal; however, it is often necessary to freeze samples for evaluation at a later time. Limited evaluation of the effect of freeze-thawing of tendon tissue samples on inherent magnetic resonance imaging (MRI) parameters, such as ultrashort echo time (UTE) T2* values, have been performed to date. Methods This study performed UTE MRI on 14 bovine patellar tendons at harvest and after four consecutive freeze-thaw cycles. Results Results demonstrated a small but significant reduction (12%) in tendon T2* values after the first freeze thaw cycle, but not after successive cycles. Tendons from juvenile animals with open physis had a significant reduction of T2* following a single freeze thaw cycle, P<0.0001. Conclusions The results of this study emphasize the importance of using uniform tendon storage protocols when using UTE MRI in preclinical models. PMID:26029639

Tendon transfer to reconstruct wrist extension in children with obstetric brachial plexus palsy.

PubMed

Al-Qattan, M M

2003-04-01

This study reports on 20 children with obstetric brachial plexus palsy who underwent a tendon transfer to reconstruct wrist extension. The mean age at the time of tendon transfer was 8 years. There were seven patients with Erb's palsy and the remaining 13 had total palsy. The flexor carpi ulnaris was utilized 15 times and the flexor carpi radialis five times. The transferred tendon was sutured to the tendon of the extensor carpi radialis brevis. The result of the transfer was assessed according to a modified Medical Research Council (MRC) muscle grading system. A good result was obtained in 18 patients (modified MRC grade of 4) and a fair result (modified MRC grade of 3) in two. The choice of tendon transfer to reconstruct the wrist drop deformity in various conditions including adult traumatic brachial plexus injuries is discussed.

Single-Stage Reconstruction of Achilles Tendon and Overlying Tissue With the Extended Temporoparietal Fasciagaleal Flap--23-Year Follow-Up and the Review of the Literature.

PubMed

Dobke, Marek; Suliman, Ahmed; Mackert, Gina A; Herrera, Fernando A; Singer, Robert; Nelson, Jeffrey

2016-05-01

In the absence of an established "gold standard" for complex Achilles tendon and regional soft tissue defect reconstruction, many techniques have been advocated. Two cases describing a novel technique of successful repair with the review of literature are presented. The underlying problem consisted of Achilles tendon necrosis with local inflammation in the first case and tendon contracture with foot malposition due to a burn injury in the other. Each patient, upon debridement, had a 6-cm Achilles tendon defect with associated overlying soft tissue deficits reconstructed with an extended temporoparietal fasciagaleal flap and a split thickness skin graft. Both cases highlight the successful functional and aesthetic quality as well as the durability of concurrent vascularized tendon and soft tissue replacement and coverage in 2 distinct clinical scenarios.

Specialisation of extracellular matrix for function in tendons and ligaments

PubMed Central

Birch, Helen L.; Thorpe, Chavaunne T.; Rumian, Adam P.

2013-01-01

Summary Tendons and ligaments are similar structures in terms of their composition, organisation and mechanical properties. The distinction between them stems from their anatomical location; tendons form a link between muscle and bone while ligaments link bones to bones. A range of overlapping functions can be assigned to tendon and ligaments and each structure has specific mechanical properties which appear to be suited for particular in vivo function. The extracellular matrix in tendon and ligament varies in accordance with function, providing appropriate mechanical properties. The most useful framework in which to consider extracellular matrix differences therefore is that of function rather than anatomical location. In this review we discuss what is known about the relationship between functional requirements, structural properties from molecular to gross level, cellular gene expression and matrix turnover. The relevance of this information is considered by reviewing clinical aspects of tendon and ligament repair and reconstructive procedures. PMID:23885341

Anatomic and isometric points on femoral attachment site of popliteus muscle-tendon complex for the posterolateral corner reconstruction.

PubMed

Yang, Jae-Hyuk; Lim, Hong Chul; Bae, Ji Hoon; Fernandez, Harry; Bae, Tae Soo; Wang, Joon Ho

2011-10-01

Descriptive laboratory study. The femoral anatomic insertion site and the optimal isometric point of popliteus tendon for posterolateral reconstruction are not well known. Purpose of this study was to determine the relative relationship between the femoral anatomic insertion and isometric point of popliteus muscle-tendon complex with the lateral epicondyle of femur. Thirty unpaired cadaveric knees were dissected to determine the anatomic femoral insertion of the popliteus tendon. The distance and the angle from the lateral epicondyle of femur to the center of the anatomic insertion of the popliteus tendon were measured using digital caliper and goniometer. Eight unpaired fresh cadaveric knees were examined to determine the optimal isometric point of femoral insertion of popliteus tendon using computer-controlled motion capture analysis system (Motion Analysis, CA, USA). Distances from targeted tibial tunnel for popliteus tendon reconstruction to the 35 points gained on the lateral surface of femur were recorded at 0, 30, 60, 90, and 120° knee flexion. A point with the least excursion (<2.0 mm) was determined as the isometric point. The center of anatomic insertion points and the optimal isometric point for the main fibers of popliteus tendon were found to be posterior and distal to the lateral epicondyle of femur. The distance from the lateral epicondyle of femur to the center of anatomic femoral insertion of popliteus tendon was 11.3 ± 1.2 mm (mean ± SD). The angle between long axis of femur and the line from lateral epicondyle of femur to anatomic femoral insertion of popliteus tendon was 31.4 ± 5.3°. The isometric points for the femoral insertion of popliteus muscle-tendon complex were situated posterior and distal to the lateral epicondyle in all 8 knees. The distance between the least excursion point and the lateral epicondyle was calculated as 10.4 ± 1.7 mm. The angle between the long axis of femur and the line from lateral epicondyle of femur to optimum isometric point of popliteus tendon was calculated as 41.3 ± 14.9°. The optimal isometric point for the femoral insertion of popliteus muscle-tendon complex is situated posterior and distal to the lateral epicondyle of femur. Femoral tunnel for "posterolateral corner sling procedure" should be placed at this point to achieve least amount of graft excursion during knee motion.

The Size of the Radial Tuberosity is Not Related to the Occurrence of Distal Biceps Tendon Ruptures: A Case-Control Study.

PubMed

Kodde, Izaäk F; van den Bekerom, Michel P J; Mulder, Paul G H; Eygendaal, Denise

2016-01-01

Hypertrophic changes at the radial tuberosity have traditionally been related to distal biceps tendon degeneration and rupture. From supination to pronation of the forearm, the space available for the distal biceps tendon between de lateral ulna and radial bicipital tuberosity (RBT) decreases by almost 50%. A hypertrophic change at the radial tuberosity further reduces this space with impingement of the distal biceps tendon as a result. The purpose of this study was to evaluate whether the size of the RBT plays a role in the pathophysiology of distal biceps tendon ruptures. Twenty-two consecutive patients with a surgically proven distal biceps tendon rupture were matched to controls, in a 1:1 ratio. The size of the RBT was expressed as a ratio of the maximum diameter of the radius at the RBT to the diameter of the diaphysis just distal to the RBT (RD ratio), measured on standard radiographs of the elbow. The RD ratio of patients and matched controls were compared. The mean RD ratio in control group was 1.25 and not significantly different from the mean 1.30 in the group of patients with a distal biceps tendon rupture. Each 0.1 point increase in RD ratio results in an estimated 60% increase of the rupture odds, which was not significant either. Based on the RD ratio on conventional radiographs of the elbow, there was no significant difference in RBT size between patients with a distal biceps tendon rupture and matched controls without biceps tendon pathology.

Tendon Reconstruction with Tissue Engineering Approach--A Review.

PubMed

Verdiyeva, Gunay; Koshy, Kiron; Glibbery, Natalia; Mann, Haroon; Seifalian, Alexander M

2015-09-01

Tendon injuries are a common and rising occurrence, associated with significant impairment to quality of life and financial burden to the healthcare system. Clinically, they represent an unresolved problem, due to poor natural tendon healing and the inability of current treatment strategies to restore the tendon to its native state. Tissue engineering offers a promising alternative, with the incorporation of scaffolds, cells and growth factors to support the complete regeneration of the tendon. The materials used in tendon engineering to date have provided significant advances in structural integrity and biological compatibility and in many cases the results obtained are superior to those observed in natural healing. However, grafts fail to reproduce the qualities of the pre-injured tendon and each has weaknesses subject to its constituent parts. Furthermore, many materials and cell types are being investigated concurrently, with seemingly little association or comparison between research results. In this review the properties of the most-investigated and effective components have been appraised in light of the surrounding literature, with research from early in-vitro experiments to clinical trials being discussed. Extensive comparisons have been made between scaffolds, cell types and growth factors used, listing strengths and weaknesses to provide a stable platform for future research. Promising future endeavours are also described in the field of nanocomposite material science, stem cell sources and growth factors, which may bypass weaknesses found in individual elements. The future of tendon engineering looks bright, with growing understanding in material technology, cell and growth factor application and encouraging recent advances bringing us ever closer to regenerating the native tendon.

Modelling tendon excursions and moment arms of the finger flexors: anatomic fidelity versus function.

PubMed

Kociolek, Aaron M; Keir, Peter J

2011-07-07

A detailed musculoskeletal model of the human hand is needed to investigate the pathomechanics of tendon disorders and carpal tunnel syndrome. The purpose of this study was to develop a biomechanical model with realistic flexor tendon excursions and moment arms. An existing upper extremity model served as a starting point, which included programmed movement of the index finger. Movement capabilities were added for the other fingers. Metacarpophalangeal articulations were modelled as universal joints to simulate flexion/extension and abduction/adduction while interphalangeal articulations used hinges to represent flexion. Flexor tendon paths were modelled using two approaches. The first method constrained tendons with control points, representing annular pulleys. The second technique used wrap objects at the joints as tendon constraints. Both control point and joint wrap models were iteratively adjusted to coincide with tendon excursions and moment arms from a anthropometric regression model using inputs for a 50th percentile male. Tendon excursions from the joint wrap method best matched the regression model even though anatomic features of the tendon paths were not preserved (absolute differences: mean<0.33 mm, peak<0.74 mm). The joint wrap model also produced similar moment arms to the regression (absolute differences: mean<0.63 mm, peak<1.58 mm). When a scaling algorithm was used to test anthropometrics, the scaled joint wrap models better matched the regression than the scaled control point models. Detailed patient-specific anatomical data will improve model outcomes for clinical use; however, population studies may benefit from simplified geometry, especially with anthropometric scaling. Copyright © 2011 Elsevier Ltd. All rights reserved.

High variability in strain estimation errors when using a commercial ultrasound speckle tracking algorithm on tendon tissue.

PubMed

Fröberg, Åsa; Mårtensson, Mattias; Larsson, Matilda; Janerot-Sjöberg, Birgitta; D'Hooge, Jan; Arndt, Anton

2016-10-01

Ultrasound speckle tracking offers a non-invasive way of studying strain in the free Achilles tendon where no anatomical landmarks are available for tracking. This provides new possibilities for studying injury mechanisms during sport activity and the effects of shoes, orthotic devices, and rehabilitation protocols on tendon biomechanics. To investigate the feasibility of using a commercial ultrasound speckle tracking algorithm for assessing strain in tendon tissue. A polyvinyl alcohol (PVA) phantom, three porcine tendons, and a human Achilles tendon were mounted in a materials testing machine and loaded to 4% peak strain. Ultrasound long-axis cine-loops of the samples were recorded. Speckle tracking analysis of axial strain was performed using a commercial speckle tracking software. Estimated strain was then compared to reference strain known from the materials testing machine. Two frame rates and two region of interest (ROI) sizes were evaluated. Best agreement between estimated strain and reference strain was found in the PVA phantom (absolute error in peak strain: 0.21 ± 0.08%). The absolute error in peak strain varied between 0.72 ± 0.65% and 10.64 ± 3.40% in the different tendon samples. Strain determined with a frame rate of 39.4 Hz had lower errors than 78.6 Hz as was the case with a 22 mm compared to an 11 mm ROI. Errors in peak strain estimation showed high variability between tendon samples and were large in relation to strain levels previously described in the Achilles tendon. © The Foundation Acta Radiologica 2016.

Quantitative US Elastography Can Be Used to Quantify Mechanical and Histologic Tendon Healing in a Rabbit Model of Achilles Tendon Transection.

PubMed

Yamamoto, Yohei; Yamaguchi, Satoshi; Sasho, Takahisa; Fukawa, Taisuke; Akatsu, Yorikazu; Akagi, Ryuichiro; Yamaguchi, Tadashi; Takahashi, Kenji; Nagashima, Kengo; Takahashi, Kazuhisa

2017-05-01

Purpose To determine the time-dependent change in strain ratios (SRs) at the healing site of an Achilles tendon rupture in a rabbit model of tendon transection and to assess the correlation between SRs and the mechanical and histologic properties of the healing tissue. Materials and Methods Experimental methods were approved by the institutional animal care and use committee. The Achilles tendons of 24 New Zealand white rabbits (48 limbs) were surgically transected. The SRs of Achilles tendons were calculated by using compression-based quantitative ultrasonographic elastography measurements obtained 2, 4, 8, and 12 weeks after transection. After in vivo elastography, the left Achilles tendon was harvested for mechanical testing of ultimate load, ultimate stress, elastic modulus, and linear stiffness, and the right tendons were harvested for tissue histologic analysis with the Bonar scale. Time-dependent changes in SRs, mechanical parameters, and Bonar scale scores were evaluated by using repeated-measures analysis of variance. The correlation between SRs and each measured variable was evaluated by using the Spearman rank correlation coefficient. Results Mean SRs and Bonar scale values decreased as a function of time after transection, whereas mechanical parameters increased (P < .001). SR correlated with ultimate stress (ρ = 0.68, P <.001,) elastic modulus (ρ = 0.74, P <.001), and the Bonar scale (ρ = 0.87, P <.001). Conclusion Quantitative elastography could be a useful method with which to evaluate mechanical and histologic properties of the healing tendon. © RSNA, 2017 Online supplemental material is available for this article.

The structure of the insertions of the tendons of biceps brachii, triceps and brachialis in elderly dissecting room cadavers.

PubMed Central

Benjamin, M; Newell, R L; Evans, E J; Ralphs, J R; Pemberton, D J

1992-01-01

The terminal portions of the tendon of brachialis, and the distal tendons of biceps brachii and triceps, were compared by routine histology. All tendons came from elderly dissecting room cadavers. There were pronounced quantitative differences between the 3 tendons in (1) the thickness of the attachment-zone fibrocartilage, (2) the thickness of cortical calcified tissue, and (3) the percentage of bone to marrow. There was significantly more uncalcified fibrocartilage at the attachment of biceps than at the other sites, reflecting greater range of movement of the tendon at this site. The thickness of cortical calcified tissue and the percentage of bone to marrow were significantly greater at the attachment of brachialis than either biceps or triceps. The large quantities of bone at the attachment of brachialis may be related more to the importance of the coronoid process in buttressing the elbow joint than to any special requirement for large amounts of calcified tissue at the tendon attachment. Near its attachment zone, the biceps tendon splits into superficial and deep laminae that are distinct from the macroscopic subdivision of this tendon. It is suggested that the lamination may facilitate the movements of pronation and supination. In support of this, the deep portion of the superficial lamina contained fibrocartilage where it rubbed against the attachment-zone of the deep lamina. In one body, the fibrocartilage of the biceps attachment-zone was subject to degenerative changes, including cell clumping and matrix fissuring. Images Fig. 2 Fig. 3 PMID:1506288

The use of motion analysis to measure pain-related behaviour in a rat model of degenerative tendon injuries.

PubMed

Fu, Sai-Chuen; Chan, Kai-Ming; Chan, Lai-Shan; Fong, Daniel Tik-Pui; Lui, Po-Yee Pauline

2009-05-15

Chronic tendinopathy is characterized with longstanding activity-related pain with degenerative tendon injuries. An objective tool to measure painful responses in animal models is essential for the development of effective treatment for tendinopathy. Gait analysis has been developed to monitor the inflammatory pain in small animals. We reported the use of motion analysis to monitor gait changes in a rat model of degenerative tendon injury. Intratendinous injection of collagenase into the left patellar tendon of Sprague Dawley rat was used to induce degenerative tendon injury, while an equal volume of saline was injected in the control groups. Motion analyses with a high speed video camera were performed on all rats at pre-injury, 2, 4, 8, 12 or 16 weeks post injection. In the end-point study, the rats were sacrificed to obtain tendon samples for histological examination after motion analyses. In the follow-up study, repeated motion analyses were performed on another group of collagenase-treated and saline-treated rats. The results showed that rats with injured patellar tendon exhibited altered walking gait as compared to the controls. The change in double stance duration in the collagenase-treated rats was reversible by administration of buprenorphrine (p=0.029), it suggested that the detected gait changes were associated with pain. Comparisons of end-point and follow-up studies revealed the confounding effects of training, which led to higher gait velocities and probably a different adaptive response to tendon pain in the trained rats. The results showed that motion analysis could be used to measure activity-related chronic tendon pain.

Degeneration of the long biceps tendon: comparison of MRI with gross anatomy and histology.

PubMed

Buck, Florian M; Grehn, Holger; Hilbe, Monika; Pfirrmann, Christian W A; Manzanell, Silvana; Hodler, Jürg

2009-11-01

The objective of our study was to relate alterations in biceps tendon diameter and signal on MR images to gross anatomy and histology. T1-weighted, T2-weighted fat-saturated, and proton density-weighted fat-saturated spin-echo sequences were acquired in 15 cadaveric shoulders. Biceps tendon diameter (normal, flattened, thickened, and partially or completely torn) and signal intensity (compared with bone, fat, muscle, and joint fluid) were graded by two readers independently and in a blinded fashion. The distance of tendon abnormalities from the attachment at the glenoid were noted in millimeters. MRI findings were related to gross anatomic and histologic findings. On the basis of gross anatomy, there were six normal, five flattened, two thickened, and two partially torn tendons. Reader 1 graded nine diameter changes correctly, missed two, and incorrectly graded four. The corresponding values for reader 2 were seven, one, and five, respectively, with kappa = 0.75. Histology showed mucoid degeneration (n = 13), lipoid degeneration (n = 7), and fatty infiltration (n = 6). At least one type of abnormality was found in each single tendon. Mucoid degeneration was hyperintense compared with fatty infiltration on T2-weighted fat-saturated images and hyperintense compared with magic-angle artifacts on proton density-weighted fat-saturated images. MRI-based localization of degeneration agreed well with histologic findings. Diameter changes are specific but not sensitive in diagnosing tendinopathy of the biceps tendon. Increased tendon signal is most typical for mucoid degeneration but should be used with care as a sign of tendon degeneration.

Ankle morphology amplifies calcaneus movement relative to triceps surae muscle shortening.

PubMed

Csapo, R; Hodgson, J; Kinugasa, R; Edgerton, V R; Sinha, S

2013-08-15

The present study investigated the mechanical role of the dorsoventral curvature of the Achilles tendon in the conversion of the shortening of the plantarflexor muscles into ankle joint rotation. Dynamic, sagittal-plane magnetic resonance spin-tagged images of the ankle joint were acquired in six healthy subjects during both passive and active plantarflexion movements driven by a magnetic resonance compatible servomotor-controlled foot-pedal device. Several points on these images were tracked to determine the 1) path and deformation of the Achilles tendon, 2) ankle's center of rotation, and 3) tendon moment arms. The degree of mechanical amplification of joint movement was calculated as the ratio of the displacements of the calcaneus and myotendinous junction. In plantarflexion, significant deflection of the Achilles tendon was evident in both the passive (165.7 ± 7.4°; 180° representing a straight tendon) and active trials (166.9 ± 8.8°). This bend in the dorsoventral direction acts to move the Achilles tendon closer to the ankle's center of rotation, resulting in an ∼5% reduction of moment arm length. Over the entire range of movement, the overall displacement of the calcaneus exceeded the displacement of the myotendinous junction by ∼37%, with the mechanical gains being smaller in dorsi- and larger in plantarflexed joint positions. This is the first study to assess noninvasively and in vivo using MRI the curvature of the Achilles tendon during both passive and active plantarflexion movements. The dorsoventral tendon curvature amplifies the shortening of the plantarflexor muscles, resulting in a greater displacement of the tendon's insertion into the calcaneus compared with its origin.

Collagen V haploinsufficiency in a murine model of classic Ehlers-Danlos syndrome is associated with deficient structural and mechanical healing in tendons.

PubMed

Johnston, Jessica M; Connizzo, Brianne K; Shetye, Snehal S; Robinson, Kelsey A; Huegel, Julianne; Rodriguez, Ashley B; Sun, Mei; Adams, Sheila M; Birk, David E; Soslowsky, Louis J

2017-12-01

Classic Ehlers-Danlos syndrome (EDS) patients suffer from connective tissue hyperelasticity, joint instability, skin hyperextensibility, tissue fragility, and poor wound healing due to heterozygous mutations in COL5a1 or COL5a2 genes. This study investigated the roles of collagen V in establishing structure and function in uninjured patellar tendons as well as in the injury response using a Col5a1 +/- mouse, a model for classic EDS. These analyses were done comparing tendons from a classic EDS model (Col5a1 +/- ) with wild-type controls. Tendons were subjected to mechanical testing, histological, and fibril analysis before injury as well as 3 and 6 weeks after injury. We found that Col5a1 +/- tendons demonstrated diminished recovery of mechanical competency after injury as compared to normal wild-type tendons, which recovered their pre-injury values by 6 weeks post injury. Additionally, the Col5a1 +/- tendons demonstrated altered fibril morphology and diameter distributions compared to the wild-type tendons. This study indicates that collagen V plays an important role in regulating collagen fibrillogenesis and the associated recovery of mechanical integrity in tendons after injury. In addition, the dysregulation with decreased collagen V expression in EDS is associated with a diminished injury response. The results presented herein have the potential to direct future targeted therapeutics for classic EDS patients. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2707-2715, 2017. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Detection of partial-thickness tears in ligaments and tendons by Stokes-polarimetry imaging

NASA Astrophysics Data System (ADS)

Kim, Jihoon; John, Raheel; Walsh, Joseph T.

2008-02-01

A Stokes polarimetry imaging (SPI) system utilizes an algorithm developed to construct degree of polarization (DoP) image maps from linearly polarized light illumination. Partial-thickness tears of turkey tendons were imaged by the SPI system in order to examine the feasibility of the system to detect partial-thickness rotator cuff tear or general tendon pathology. The rotating incident polarization angle (IPA) for the linearly polarized light provides a way to analyze different tissue types which may be sensitive to IPA variations. Degree of linear polarization (DoLP) images revealed collagen fiber structure, related to partial-thickness tears, better than standard intensity images. DoLP images also revealed structural changes in tears that are related to the tendon load. DoLP images with red-wavelength-filtered incident light may show tears and related organization of collagen fiber structure at a greater depth from the tendon surface. Degree of circular polarization (DoCP) images exhibited well the horizontal fiber orientation that is not parallel to the vertically aligned collagen fibers of the tendon. The SPI system's DOLP images reveal alterations in tendons and ligaments, which have a tissue matrix consisting largely of collagen, better than intensity images. All polarized images showed modulated intensity as the IPA was varied. The optimal detection of the partial-thickness tendon tears at a certain IPA was observed. The SPI system with varying IPA and spectral information can improve the detection of partial-thickness rotator cuff tears by higher visibility of fiber orientations and thereby improve diagnosis and treatment of tendon related injuries.

Epigenetic regulation of metalloproteinases and their inhibitors in rotator cuff tears

PubMed Central

Caires dos Santos, Leonardo; Martins de Oliveira, Adrielle; Santoro Belangero, Paulo; Antônio Figueiredo, Eduardo; Cohen, Carina; de Seixas Alves, Felipe; Hiromi Yanaguizawa, Wânia; Vicente Andreoli, Carlos; de Castro Pochini, Alberto; Ejnisman, Benno; Cardoso Smith, Marília; de Seixas Alves, Maria Teresa; Cohen, Moises

2017-01-01

Rotator cuff tear is a common orthopedic condition. Metalloproteinases (MMP) and their inhibitors (TIMP) seem to play a role in the development of joint injuries and in the failure of tissue healing. However, the mechanisms of regulation of gene expression in tendons are still unknown. Epigenetic mechanisms, such as DNA methylation and microRNAs regulation, are involved in the dynamic control of gene expression. Here, the mRNA expression and DNA methylation status of MMPs (MMP1, MMP2, MMP3, MMP9, MMP13, and MMP14) and TIMPs (TIMP1-3) and the expression of miR-29 family members in ruptured supraspinatus tendons were compared with non-injured tendons of individuals without this lesion. Additionally, the gene expression and methylation status at the edge of the ruptured tendon were compared with macroscopically non-injured rotator cuff tendon samples from the anterior and posterior regions of patients with tendon tears. Moreover, the possible associations between the molecular alterations and the clinical and histologic characteristics were investigated. Dysregulated expression and DNA methylation of MMP and TIMP genes were found across the rotator cuff tendon samples of patients with supraspinatus tears. These alterations were influenced at least in part by age at surgery, sex, smoking habit, tear size, and duration of symptoms. Alterations in the studied MMP and TIMP genes may contribute to the presence of microcysts, fissures, necrosis, and neovascularization in tendons and may thus be involved in the tendon healing process. In conclusion, MMPs and their inhibitors are regulated by epigenetic modifications and may play a role in rotator cuff tears. PMID:28902861

Magnetic resonance anatomy of the superior part of the rotator cuff in normal shoulders, assessment and practical implication.

PubMed

Michelin, Paul; Trintignac, Adrien; Dacher, Jean Nicolas; Carvalhana, Gilbert; Lefebvre, Valentin; Duparc, Fabrice

2014-12-01

The superior part of the rotator cuff consists of the anterior (SSa) and posterior (SSp) parts of the supraspinatus tendon, the infraspinatus (IS) tendon plus the articular capsule. An overlap of the distal SSp tendon by the anterior part of the IS one has been anatomically demonstrated; the insertion area of the IS is more anterior than currently believed. The aim of our study was to assess this complex architecture through standard MRI scans. Twenty-five healthy volunteers underwent a shoulder MRI. Three planes T2 fat saturation sequences were read in consensus by two radiologists. The SSa, the SSp, the IS tendons and the articular capsule were assessed for visibility. The patterns of demarcation of each structure from adjacent ones were assessed. The width and the thickness of each tendinous band were measured on sagittal images. The SSa, the SSp and the IS tendons were distinguishable in all patients. The anterior part of the IS tendon overlapped the SSp tendon to reach a quite anterior insertion into the greater tuberosity of the humerus. The SSa, the SSp and the IS tendons were 6.5-3.4, 15.1-2.8 and 26.8-2.2 mm wide and thick, respectively. MR images of the normal superior rotator cuff are consistent with latest anatomical descriptions. The distal superposition of the IS over the SSp tendon should be considered regarding the linear increased signal areas and the commonly named "partial thickness ruptures" of the superior rotator cuff as well as the fatty infiltration of the IS muscle.

Tenogenesis of bone marrow-, adipose-, and tendon-derived stem cells in a dynamic bioreactor.

PubMed

Youngstrom, Daniel W; LaDow, Jade E; Barrett, Jennifer G

2016-11-01

Tendons are frequently damaged and fail to regenerate, leading to pain, loss of function, and reduced quality of life. Mesenchymal stem cells (MSCs) possess clinically useful tissue-regenerative properties and have been exploited for use in tendon tissue engineering and cell therapy. However, MSCs exhibit phenotypic heterogeneity based on the donor tissue used, and the efficacy of cell-based treatment modalities may be improved by optimizing cell source based on relative differentiation capacity. Equine MSCs were isolated from bone marrow (BM), adipose (AD), and tendon (TN), expanded in monolayer prior to seeding on decellularized tendon scaffolds (DTS), and cell-laden constructs were placed in a bioreactor designed to mimic the biophysical environment of the tendon. It was hypothesized that TN MSCs would differentiate toward a tendon cell phenotype better than BM and AD MSCs in response to a conditioning period involving cyclic mechanical stimulation for 1 hour per day at 3% strain and 0.33 Hz. All cell types integrated into DTS adopted an elongated morphology similar to tenocytes, expressed tendon marker genes, and improved tissue mechanical properties after 11 days. TN MSCs expressed the greatest levels of scleraxis, collagen type-I, and cartilage oligomeric matrix protein. Major histocompatibility class-II protein mRNA expression was not detected in any of the MSC types, suggesting low immunogenicity for allogeneic transplantation. The results suggest that TN MSCs are the ideal cell type for regenerative medicine therapies for tendinopathies, exhibiting the most mature tendon-like phenotype in vitro. When TN MSCs are unavailable, BM or AD MSCs may serve as robust alternatives.

Plyometric Training Favors Optimizing Muscle–Tendon Behavior during Depth Jumping

PubMed Central

Hirayama, Kuniaki; Iwanuma, Soichiro; Ikeda, Naoki; Yoshikawa, Ayumi; Ema, Ryoichi; Kawakami, Yasuo

2017-01-01

The purpose of the present study was to elucidate how plyometric training improves stretch–shortening cycle (SSC) exercise performance in terms of muscle strength, tendon stiffness, and muscle–tendon behavior during SSC exercise. Eleven men were assigned to a training group and ten to a control group. Subjects in the training group performed depth jumps (DJ) using only the ankle joint for 12 weeks. Before and after the period, we observed reaction forces at foot, muscle–tendon behavior of the gastrocnemius, and electromyographic activities of the triceps surae and tibialis anterior during DJ. Maximal static plantar flexion strength and Achilles tendon stiffness were also determined. In the training group, maximal strength remained unchanged while tendon stiffness increased. The force impulse of DJ increased, with a shorter contact time and larger reaction force over the latter half of braking and initial half of propulsion phases. In the latter half of braking phase, the average electromyographic activity (mEMG) increased in the triceps surae and decreased in tibialis anterior, while fascicle behavior of the gastrocnemius remained unchanged. In the initial half of propulsion, mEMG of triceps surae and shortening velocity of gastrocnemius fascicle decreased, while shortening velocity of the tendon increased. These results suggest that the following mechanisms play an important role in improving SSC exercise performance through plyometric training: (1) optimization of muscle–tendon behavior of the agonists, associated with alteration in the neuromuscular activity during SSC exercise and increase in tendon stiffness and (2) decrease in the neuromuscular activity of antagonists during a counter movement. PMID:28179885

Reduced effects of tendon vibration with increased task demand during active, cyclical ankle movements

PubMed Central

Floyd, Lisa M.; Holmes, Taylor C.; Dean, Jesse C.

2013-01-01

Tendon vibration can alter proprioceptive feedback, one source of sensory information which humans can use to produce accurate movements. However, the effects of tendon vibration during functional movement vary depending on the task. For example, ankle tendon vibration has considerably smaller effects during walking than standing posture. The purpose of this study was to test whether the effects of ankle tendon vibration are predictably influenced by the mechanical demands of a task, as quantified by peak velocity. Twelve participants performed symmetric, cyclical ankle plantarflexion/dorsiflexion movements while lying prone with their ankle motion unconstrained. The prescribed movement period (1s, 3s) and peak-to-peak amplitude (10°, 15°, 20°) were varied across trials; shorter movement periods or larger amplitudes increased the peak velocity. In some trials, vibration was continuously and simultaneously applied to the right ankle plantarflexor and dorsiflexor tendons, while the left ankle tendons were never vibrated. The vibration frequency (40, 80, 120, 160 Hz) was varied across trials. During trials without vibration, participants accurately matched the movement of their ankles. The application of 80 Hz vibration to the right ankle tendons significantly reduced the amplitude of right ankle movement. However, the effect of vibration was smaller during more mechanically demanding (i.e. higher peak velocity) movements. Higher vibration frequencies had larger effects on movement accuracy, possibly due to parallel increases in vibration amplitude. These results demonstrate that the effects of ankle tendon vibration are dependent on the mechanical demand of the task being performed, but cannot definitively identify the underlying physiological mechanism. PMID:24136344

The development of confocal arthroscopy as optical histology for rotator cuff tendinopathy.

PubMed

Wu, J-P; Walton, M; Wang, A; Anderson, P; Wang, T; Kirk, T B; Zheng, M H

2015-09-01

MRI, ultrasound and video arthroscopy are traditional imaging technologies for noninvasive or minimal invasive assessment of the rotator cuff tendon pathology. However, these imaging modalities do not have sufficient resolution to demonstrate the pathology of rotator cuff tendons at a microstructural level. Therefore, they are insensitive to low-level tendon diseases. Although traditional histology can be used to analyze the physiology of rotator cuff tendons, it requires biopsy that traumatizes the rotator cuff, thus, potentially comprising the mechanical properties of tendons. Besides, it cannot offer real-time histological information. Confocal endoscopy offers a way to assess the microstructural disorder in tissues without biopsy. However, the application of this useful technique for detecting low-level tendon diseases has been restricted by using clinical grade fluorescent contrast agent to acquire high-resolution microstructural images of tendons. In this study, using a clinical grade sodium fluorescein contrast agent, we have reported the development of confocal arthroscopy for optical histological assessment without biopsy. The confocal arthroscopic technique was able to demonstrate rotator cuff tendinopathy in human cadavers, which appeared macroscopically normal under video arthroscopic examinations. The tendinopathy status of the rotator cuff tendons was confirmed by corresponding traditional histology. The development of confocal arthroscopy may provide a minimally invasive imaging technique for real-time histology of rotator cuff without the need for tissue biopsy. This technique has the potential for surgeons to gain in real time the histological information of rotator cuff tendons, which may assist planning repair strategies and potentially improve intervention outcomes. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

Greater inadvertent muscle damage in direct anterior approach when compared with the direct superior approach for total hip arthroplasty.

PubMed

Amanatullah, D F; Masini, M A; Roger, D J; Pagnano, M W

2016-08-01

We wished to quantify the extent of soft-tissue damage sustained during minimally invasive total hip arthroplasty through the direct anterior (DA) and direct superior (DS) approaches. In eight cadavers, the DA approach was performed on one side, and the DS approach on the other, a single brand of uncemented hip prosthesis was implanted by two surgeons, considered expert in their surgical approaches. Subsequent reflection of the gluteus maximus allowed the extent of muscle and tendon damage to be measured and the percentage damage to each anatomical structure to be calculated. The DA approach caused substantially greater damage to the gluteus minimus muscle and tendon when compared with the DS approach (t-test, p = 0.049 and 0.003, respectively). The tensor fascia lata and rectus femoris muscles were damaged only in the DA approach. There was no difference in the amount of damage to the gluteus medius muscle and tendon, piriformis tendon, obturator internus tendon, obturator externus tendon or quadratus femoris muscle between approaches. The posterior soft-tissue releases of the DA approach damaged the gluteus minimus muscle and tendon, piriformis tendon and obturator internus tendon. The DS approach caused less soft-tissue damage than the DA approach. However the clinical relevance is unknown. Further clinical outcome studies, radiographic evaluation of component position, gait analyses and serum biomarker levels are necessary to evaluate and corroborate the safety and efficacy of the DS approach. Cite this article: Bone Joint J 2016;98-B1036-42. ©2016 The British Editorial Society of Bone & Joint Surgery.

Comparison of Clinical and Structural Outcomes by Subscapularis Tendon Status in Massive Rotator Cuff Tear.

PubMed

Lee, Sung Hyun; Nam, Dae Jin; Kim, Se Jin; Kim, Jeong Woo

2017-09-01

The subscapularis tendon is essential in maintaining normal glenohumeral biomechanics. However, few studies have addressed the outcomes of tears extending to the subscapularis tendon in massive rotator cuff tears. To assess the clinical and structural outcomes of arthroscopic repair of massive rotator cuff tears involving the subscapularis. Cohort study; Level of evidence, 3. Between January 2010 and January 2014, 122 consecutive patients with massive rotator cuff tear underwent arthroscopic rotator cuff repair. Overall, 122 patients were enrolled (mean age, 66 years; mean follow-up period, 39.5 months). Patients were categorized into 3 groups based on subscapularis tendon status: intact subscapularis tendon (I group; n = 45), tear involving less than the superior one-third (P group; n = 35), and tear involving more than one-third of the subscapularis tendon (C group; n = 42). All rotator cuff tears were repaired; however, subscapularis tendon tears involving less than the superior one-third in P group were only debrided. Pain visual analog scale, Constant, and American Shoulder and Elbow Surgeons scores and passive range of motion were measured preoperatively and at the final follow-up. Rotator cuff integrity, global fatty degeneration index, and occupation ratio were determined via magnetic resonance imaging preoperatively and 6 months postoperatively. We identified 37 retears (31.1%) based on postoperative magnetic resonance imaging evaluation. Retear rate in patients in the C group (47.6%) was higher than that in the I group (22.9%) or P group (20.0%) ( P = .011). Retear subclassification based on the involved tendons showed that subsequent subscapularis tendon retears were noted in only the C group. The improvement in clinical scores after repair was statistically significant in all groups but not different among the groups. Between-group comparison showed significant differences in preoperative external rotation ( P = .021). However, no statistically significant difference was found in any shoulder range of motion measurements after surgery. Arthroscopic repair of massive tears results in substantial improvements in shoulder function, despite the presence of combined subscapularis tears. However, this study showed a high failure rate of massive posterosuperior rotator cuff tear repair extending more than one-third of the subscapularis tendon. When combined subscapularis tendon tear was less than the superior one-third of the subscapularis tendon, arthroscopic debridement was a reasonable treatment method where comparable clinical and anatomic outcomes could be expected.

Anatomic relationship of the proximal nail matrix to the extensor hallucis longus tendon insertion.

PubMed

Palomo López, P; Becerro de Bengoa Vallejo, R; López López, D; Prados Frutos, J C; Alfonso Murillo González, J; Losa Iglesias, M E

2015-10-01

The purpose of this study was to delineate the relationship of the terminal extensor hallucis longus tendon insertion to the proximal limit of the nail matrix of the great toe. Fifty fresh-frozen human cadaver great toes with no evidence of trauma (average age, 62.5 years; 29 males and 21 females) were used for this study. Under 25X magnification, the proximal limit of the nail matrix and the terminal bony insertion of the extensor hallucis longus tendons were identified. The distance from the terminal tendon insertion to the nail matrix was ascertained using precision calipers, an optical microscope, and autocad(®) software for windows. Twenty-five great toes were placed in a neutral formalin solution and further analysed by histological longitudinal-sections. The specimens were stained with haematoxylin and eosin and examined microscopically to determine the presence of the extensor hallucis longus tendon along the dorsal aspect of the distal phalanx of each great toe. The main result we found in great toes was that the extensor tendon is between the matrix and the phalanx and extends dorsally to the distal aspect of the distal phalanx in all, 100%, specimens. The nail matrix of the great toe is not attached to the periosteum of the dorsal aspect of the base of the distal phalanx as is the case for fingers, because the extensor hallucis tendon is plantar or directly underneath the nail matrix and the tendon is dorsal to the bone. We have found that the extensor tendon is between the matrix and the phalanx and extends dorsally to the distal aspect of the distal phalanx. The nail matrix of the great toe is not attached to the periosteum of the dorsal aspect of the base of distal phalanx as is the case in fingers, because the extensor hallucis tendon is plantar or directly underneath the nail matrix and the tendon is dorsal to the bone. Our anatomic study demonstrates that the proximal limit of the matrix and nail bed of the human great toe are dorsal and overlapping the terminal extensor hallucis longus tendon until its distal bony insertion in all specimens. © 2015 European Academy of Dermatology and Venereology.

Internal Snapping Hip Syndrome: Incidence of Multiple-Tendon Existence and Outcome After Endoscopic Transcapsular Release.

PubMed

Ilizaliturri, Victor M; Suarez-Ahedo, Carlos; Acuña, Marco

2015-10-01

To report the frequency of presentation of bifid or multiple iliopsoas tendons in patients who underwent endoscopic release for internal snapping hip syndrome (ISHS) and to compare both groups. A consecutive series of patients with ISHS were treated with endoscopic transcapsular release of the iliopsoas tendon at the central compartment and prospectively followed up. The inclusion criteria were patients with a diagnosis of ISHS with failure of conservative treatment. During the procedure, the presence of a bifid tendon was intentionally looked for. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were evaluated preoperatively and at last follow-up. Four patients presented with a bifid tendon and one patient had 3 tendons. At a minimum of 12 months' follow-up, the presence of snapping recurrence was evaluated and the WOMAC scores were compared between both groups. Among 279 hip arthroscopies, 28 patients underwent central transcapsular iliopsoas tendon release. The mean age was 29.25 years (range, 16 to 65 years; 6 left and 22 right hips). Group 1 included 5 patients with multiple tendons; the remaining patients formed group 2 (n = 23). None of the patients presented with ISHS recurrence. The mean WOMAC score in group 1 was 39 points (95% confidence interval [CI], 26.2 to 55.4 points) preoperatively and 73.6 points (95% CI, 68.4 to 79.6 points) at last follow-up. In group 2 the mean WOMAC score was 47.21 points (95% CI, 44.4 to 58.2 points) preoperatively and 77.91 points (95% CI, 67.8 to 83.4 points) at last follow-up. We identified a bifid tendon retrospectively on magnetic resonance arthrograms in 3 of the 5 cases that were found to have multiple tendons during surgery. None of these were recognized before the procedures. In this series the surgeon intentionally looked for multiple tendons, which were found in 17.85% of the cases. Clinical results in patients with single- and multiple-tendon snapping seem to be similarly adequate. However, the possibility of a type II error should be considered given the small number of patients. Level IV. Copyright © 2015 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Reconstruction of Ligament and Tendon Defects Using Cell Technologies.

PubMed

Chailakhyan, R K; Shekhter, A B; Ivannikov, S V; Tel'pukhov, V I; Suslin, D S; Gerasimov, Yu V; Tonenkov, A M; Grosheva, A G; Panyushkin, P V; Moskvina, I L; Vorob'eva, N N; Bagratashvili, V N

2017-02-01

We studied the possibility of restoring the integrity of the Achilles tendon in rabbits using autologous multipotent stromal cells. Collagen or gelatin sponges populated with cells were placed in a resorbable Vicryl mesh tube and this tissue-engineered construct was introduced into a defect of the middle part of the Achilles tendon. In 4 months, histological analysis showed complete regeneration of the tendon with the formation of parallel collagen fibers, spindle-shaped tenocytes, and newly formed vessels.

Immunolocalization of Collagens (I and III) and Cartilage Oligomeric Matrix Protein in the Normal and Injured Equine Superficial Digital Flexor Tendon

PubMed Central

2013-01-01

This is a descriptive study of tendon pathology with different structural appearances of repair tissue correlated to immunolocalization of cartilage oligomeric matrix protein (COMP) and type I and III collagens and expression of COMP mRNA. The material consists of nine tendons from seven horses (5–25 years old; mean age of 10 years) with clinical tendinopathy and three normal tendons from horses (3, 3, and 13 years old) euthanized for non-orthopedic reasons. The injured tendons displayed different repair-tissue appearances with organized and disorganized fibroblastic regions as well as areas of necrosis. The normal tendons presented distinct immunoreactivity for COMP and expression of COMP mRNA and type I collagen in the normal aligned fiber structures, but no immunolabeling of type III collagen. However, immunoreactivity for type III collagen was present in the endotenon surrounding the fiber bundles, where no expression of COMP could be seen. Immunostaining for type I and III collagens was present in all of the pathologic regions indicating repair tissue. Interestingly, the granulation tissues showed immunostaining for COMP and expression of COMP mRNA, indicating a role for COMP in repair and remodeling of the tendon after fiber degeneration and rupture. The present results suggest that not only type III collagen but also COMP is involved in the repair and remodeling processes of the tendon. PMID:23020676

Proteomic Analysis of Tendon Extracellular Matrix Reveals Disease Stage-specific Fragmentation and Differential Cleavage of COMP (Cartilage Oligomeric Matrix Protein)*

PubMed Central

Dakin, Stephanie Georgina; Smith, Roger Kenneth Whealands; Heinegård, Dick; Önnerfjord, Patrik; Khabut, Areej; Dudhia, Jayesh

2014-01-01

During inflammatory processes the extracellular matrix (ECM) is extensively remodeled, and many of the constituent components are released as proteolytically cleaved fragments. These degradative processes are better documented for inflammatory joint diseases than tendinopathy even though the pathogenesis has many similarities. The aims of this study were to investigate the proteomic composition of injured tendons during early and late disease stages to identify disease-specific cleavage patterns of the ECM protein cartilage oligomeric matrix protein (COMP). In addition to characterizing fragments released in naturally occurring disease, we hypothesized that stimulation of tendon explants with proinflammatory mediators in vitro would induce fragments of COMP analogous to natural disease. Therefore, normal tendon explants were stimulated with IL-1β and prostaglandin E2, and their effects on the release of COMP and its cleavage patterns were characterized. Analyses of injured tendons identified an altered proteomic composition of the ECM at all stages post injury, showing protein fragments that were specific to disease stage. IL-1β enhanced the proteolytic cleavage and release of COMP from tendon explants, whereas PGE2 had no catabolic effect. Of the cleavage fragments identified in early stage tendon disease, two fragments were generated by an IL-1-mediated mechanism. These fragments provide a platform for the development of neo-epitope assays specific to injury stage for tendon disease. PMID:24398684

Interactions between tenocytes and monosodium urate monohydrate crystals: implications for tendon involvement in gout.

PubMed

Chhana, Ashika; Callon, Karen E; Dray, Michael; Pool, Bregina; Naot, Dorit; Gamble, Greg D; Coleman, Brendan; McCarthy, Geraldine; McQueen, Fiona M; Cornish, Jillian; Dalbeth, Nicola

2014-09-01

Advanced imaging studies have demonstrated that urate deposition in periarticular structures, such as tendons, is common in gout. The aim of this study was to investigate the effects of monosodium urate monohydrate (MSU) crystals on tenocyte viability and function. The histological appearance of tendons in joints affected by advanced gout was examined using light microscopy. In vitro, colorimetric assays and flow cytometry were used to assess cell viability in primary rat and primary human tenocytes cultured with MSU crystals. Real-time PCR was used to determine changes in the relative mRNA expression levels of tendon-related genes, and Sirius red staining was used to measure changes in collagen deposition in primary rat tenocytes. In joint samples from patients with gout, MSU crystals were identified within the tendon, adjacent to and invading into tendon, and at the enthesis. MSU crystals reduced tenocyte viability in a dose-dependent manner. MSU crystals decreased the mRNA expression of tendon collagens, matrix proteins and degradative enzymes and reduced collagen protein deposition by tenocytes. These data indicate that MSU crystals directly interact with tenocytes to reduce cell viability and function. These interactions may contribute to tendon damage in people with advanced gout. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

The effects of scaffold architecture and fibrin gel addition on tendon cell phenotype.

PubMed

Pawelec, K M; Wardale, R J; Best, S M; Cameron, R E

2015-01-01

Development of tissue engineering scaffolds relies on careful selection of pore architecture and chemistry of the cellular environment. Repair of skeletal soft tissue, such as tendon, is particularly challenging, since these tissues have a relatively poor healing response. When removed from their native environment, tendon cells (tenocytes) lose their characteristic morphology and the expression of phenotypic markers. To stimulate tendon cells to recreate a healthy extracellular matrix, both architectural cues and fibrin gels have been used in the past, however, their relative effects have not been studied systematically. Within this study, a combination of collagen scaffold architecture, axial and isotropic, and fibrin gel addition was assessed, using ovine tendon-derived cells to determine the optimal strategy for controlling the proliferation and protein expression. Scaffold architecture and fibrin gel addition influenced tendon cell behavior independently in vitro. Addition of fibrin gel within a scaffold doubled cell number and increased matrix production for all architectures studied. However, scaffold architecture dictated the type of matrix produced by cells, regardless of fibrin addition. Axial scaffolds, mimicking native tendon, promoted a mature matrix, with increased tenomodulin, a marker for mature tendon cells, and decreased scleraxis, an early transcription factor for connective tissue. This study demonstrated that both architectural cues and fibrin gel addition alter cell behavior and that the combination of these signals could improve clinical performance of current tissue engineering constructs.

[Anterior dislocation of the popliteus tendon].

PubMed

Martinez Molina, Oscar

2009-01-01

Review the most relevant aspects of the posterolateral corner anatomy of the knee, based on the analysis of papers that throughout the years have made important contributions to the knowledge of these structures. Last et al rejected the idea that the popliteal tendon is an isolated structure, suggesting rather that its variants are closely linked to other anatomical structures. The studies by Tria et al contributed the features of the tendon as it attaches to the lateral condyle, just to mention a couple of examples. This is the case of a 48 year-old female patient with a knee injury caused by an external rotation mechanism. Clinical features included pain, a protruding sensation in the lateral aspect of the knee, and voluntary pseudoblocking resulting from external rotation maneuvers. Knee arthroscopy was performed and dislocation of the popliteal tendon anterior to the lateral condyle was diagnosed, besides a longitudinal tear. The tendon was repositioned, radiofrequency was applied to both the tendon and the popliteal hiatus, and the former was kept in place with a plaster cast worn for 6 weeks. Even though the isolated tear or avulsion of the tendon has already been reported, the dislocation or instability of the popliteal tendon as it relates to the lateral femoral condyle has apparently not been approached yet. As we did in this case, other authors have also confirmed the diagnosis arthroscopically, Naver in 1985, Rose in 1988, and Burstein in 1990.

An Investigation of the Immediate Effect of Static Stretching on the Morphology and Stiffness of Achilles Tendon in Dominant and Non-Dominant Legs

PubMed Central

Chiu, Tsz-chun Roxy; Ngo, Hiu-ching; Lau, Lai-wa; Leung, King-wah; Lo, Man-him; Yu, Ho-fai; Ying, Michael

2016-01-01

Aims This study was undertaken to investigate the immediate effect of static stretching on normal Achilles tendon morphology and stiffness, and the different effect on dominant and non-dominant legs; and to evaluate inter-operator and intra-operator reliability of using shear-wave elastography in measuring Achilles tendon stiffness. Methods 20 healthy subjects (13 males, 7 females) were included in the study. Thickness, cross-sectional area and stiffness of Achilles tendons in both legs were measured before and after 5-min static stretching using grey-scale ultrasound and shear-wave elastography. Inter-operator and intra-operator reliability of tendon stiffness measurements of six operators were evaluated. Results Result showed that there was no significant change in the thickness and cross-sectional area of Achilles tendon after static stretching in both dominant and non-dominant legs (p > 0.05). Tendon stiffness showed a significant increase in non-dominant leg (p < 0.05) but not in dominant leg (p > 0.05). The inter-operator reliability of shear-wave elastography measurements was 0.749 and the intra-operator reliability ranged from 0.751 to 0.941. Conclusion Shear-wave elastography is a useful and non-invasive imaging tool to assess the immediate stiffness change of Achilles tendon in response to static stretching with high intra-operator and inter-operator reliability. PMID:27120097

Atelocollagen Enhances the Healing of Rotator Cuff Tendon in Rabbit Model.

PubMed

Suh, Dong-Sam; Lee, Jun-Keun; Yoo, Ji-Chul; Woo, Sang-Hun; Kim, Ga-Ram; Kim, Ju-Won; Choi, Nam-Yong; Kim, Yongdeok; Song, Hyun-Seok

2017-07-01

Failure of rotator cuff healing is a common complication despite the rapid development of surgical repair techniques for the torn rotator cuff. To verify the effect of atelocollagen on tendon-to-bone healing in the rabbit supraspinatus tendon compared with conventional cuff repair. Controlled laboratory study. A tear of the supraspinatus tendon was created and repaired in 46 New Zealand White rabbits. They were then randomly allocated into 2 groups (23 rabbits per group; 15 for histological and 8 for biomechanical test). In the experimental group, patch-type atelocollagen was implanted between bone and tendon during repair; in the control group, the torn tendon was repaired without atelocollagen. Each opposite shoulder served as a sham (tendon was exposed only). Histological evaluation was performed at 4, 8, and 12 weeks. Biomechanical tensile strength was tested 12 weeks after surgery. Histological evaluation scores of the experimental group (4.0 ± 1.0) were significantly superior to those of the control group (7.7 ± 2.7) at 12 weeks ( P = .005). The load to failure was significantly higher in the experimental group (51.4 ± 3.9 N) than in the control group (36.4 ± 5.9 N) ( P = .001). Histological and biomechanical studies demonstrated better results in the experimental group using atelocollagen in a rabbit model of the supraspinatus tendon tear. Atelocollagen patch could be used in the cuff repair site to enhance healing.

EGR1 induces tenogenic differentiation of tendon stem cells and promotes rabbit rotator cuff repair.

PubMed

Tao, Xu; Liu, Junpeng; Chen, Lei; Zhou, You; Tang, Kanglai

2015-01-01

The rate of healing failure after surgical repair of chronic rotator cuff tears is considerably high. The aim of this study was to investigate the function of the zinc finger transcription factor early growth response 1 (EGR1) in the differentiation of tendon stem cells (TSCs) and in tendon formation, healing, and tendon tear repair using an animal model of rotator cuff repair. Tenocyte, adipocyte, osteocyte, and chondrocyte differentiation as well as the expression of related genes were determined in EGR1-overexpressing TSCs (EGR1-TSCs) using tissue-specific staining, immunofluorescence staining, quantitative PCR, and western blotting. A rabbit rotator cuff repair model was established, and TSCs and EGR1-TSCs in a fibrin glue carrier were applied onto repair sites. The rabbits were sacrificed 8 weeks after repair operation, and tissues were histologically evaluated and tenocyte-related gene expression was determined. EGR1 induced tenogenic differentiation of TSCs and inhibited non-tenocyte differentiation of TSCs. Furthermore, EGR1 promoted tendon repair in a rabbit model of rotator cuff injury. The BMP12/Smad1/5/8 signaling pathway was involved in EGR1-induced tenogenic differentiation and rotator cuff tendon repair. EGR1 plays a key role in tendon formation, healing, and repair through BMP12/Smad1/5/8 pathway. EGR1-TSCs is a promising treatment for rotator cuff tendon repair surgeries. © 2015 S. Karger AG, Basel.

Coordinated Development of Muscles and Tendon-Like Structures: Early Interactions in the Drosophila Leg.

PubMed

Soler, Cedric; Laddada, Lilia; Jagla, Krzysztof

2016-01-01

The formation of the musculoskeletal system is a remarkable example of tissue assembly. In both vertebrates and invertebrates, precise connectivity between muscles and skeleton (or exoskeleton) via tendons or equivalent structures is fundamental for movement and stability of the body. The molecular and cellular processes underpinning muscle formation are well-established and significant advances have been made in understanding tendon development. However, the mechanisms contributing to proper connection between these two tissues have received less attention. Observations of coordinated development of tendons and muscles suggest these tissues may interact during the different steps in their development. There is growing evidence that, depending on animal model and muscle type, these interactions can take place from progenitor induction to the final step of the formation of the musculoskeletal system. Here, we briefly review and compare the mechanisms behind muscle and tendon interaction throughout the development of vertebrates and Drosophila before going on to discuss our recent findings on the coordinated development of muscles and tendon-like structures in Drosophila leg. By altering apodeme formation (the functional Drosophila equivalent of tendons in vertebrates) during the early steps of leg development, we affect the spatial localization of subsequent myoblasts. These findings provide the first evidence of the developmental impact of early interactions between muscle and tendon-like precursors, and confirm the appendicular Drosophila muscle system as a valuable model for studying these processes.

Coordinated Development of Muscles and Tendon-Like Structures: Early Interactions in the Drosophila Leg

PubMed Central

Soler, Cedric; Laddada, Lilia; Jagla, Krzysztof

2016-01-01

The formation of the musculoskeletal system is a remarkable example of tissue assembly. In both vertebrates and invertebrates, precise connectivity between muscles and skeleton (or exoskeleton) via tendons or equivalent structures is fundamental for movement and stability of the body. The molecular and cellular processes underpinning muscle formation are well-established and significant advances have been made in understanding tendon development. However, the mechanisms contributing to proper connection between these two tissues have received less attention. Observations of coordinated development of tendons and muscles suggest these tissues may interact during the different steps in their development. There is growing evidence that, depending on animal model and muscle type, these interactions can take place from progenitor induction to the final step of the formation of the musculoskeletal system. Here, we briefly review and compare the mechanisms behind muscle and tendon interaction throughout the development of vertebrates and Drosophila before going on to discuss our recent findings on the coordinated development of muscles and tendon-like structures in Drosophila leg. By altering apodeme formation (the functional Drosophila equivalent of tendons in vertebrates) during the early steps of leg development, we affect the spatial localization of subsequent myoblasts. These findings provide the first evidence of the developmental impact of early interactions between muscle and tendon-like precursors, and confirm the appendicular Drosophila muscle system as a valuable model for studying these processes. PMID:26869938

Use of three-dimensional finite element models of the lateral ankle ligaments to evaluate three surgical techniques

PubMed Central

Wang, Cheng-Wei; Muheremu, Aikeremujiang; Bai, Jing-Ping

2017-01-01

Objective To compare three surgical techniques for lateral ankle ligament reconstruction using finite element (FE) models. Methods A three-dimensional FE model of the left foot of a healthy volunteer and lateral collateral ligament injury models were developed. Three tendons [one-half of the autologous peroneus longus tendon (PLT), one-half of the peroneus brevis tendon (PBT), and an allogeneic tendon] were used for lateral collateral ligament reconstruction. The ankle varus stress and anterior drawer tests were performed to compare the three surgical techniques. Results The ankle varus stress test showed that the equivalent stresses of the anterior talofibular ligament (ATFL) (84.00 MPa) and calcaneofibular ligament (CFL) (27.01 MPa) were lower in allogeneic tendon reconstruction than in the other two techniques but similar to those of normal individuals (138.48 and 25.90 MPa, respectively). The anterior drawer test showed that the equivalent stresses of the ATFL and CFL in autologous PLT reconstruction (31.31 and 28.60 MPa, respectively) and PBT reconstruction (31.47 and 29.07 MPa, respectively) were lower than those in allogeneic tendon reconstruction (57.32 and 52.20 MPa, respectively). Conclusions The allogeneic tendon reconstruction outcome was similar to normal individuals. Allogeneic tendon reconstruction may be superior for lateral ankle ligament reconstruction without considering its complications. PMID:29239256

Tendon-driven continuum robot for neuroendoscopy: validation of extended kinematic mapping for hysteresis operation.

PubMed

Kato, Takahisa; Okumura, Ichiro; Kose, Hidekazu; Takagi, Kiyoshi; Hata, Nobuhiko

2016-04-01

The hysteresis operation is an outstanding issue in tendon-driven actuation--which is used in robot-assisted surgery--as it is incompatible with kinematic mapping for control and trajectory planning. Here, a new tendon-driven continuum robot, designed to fit existing neuroendoscopes, is presented with kinematic mapping for hysteresis operation. With attention to tension in tendons as a salient factor of the hysteresis operation, extended forward kinematic mapping (FKM) has been developed. In the experiment, the significance of every component in the robot for the hysteresis operation has been investigated. Moreover, the prediction accuracy of postures by the extended FKM has been determined experimentally and compared with piecewise constant curvature assumption. The tendons were the most predominant factor affecting the hysteresis operation of the robot. The extended FKM including friction in tendons predicted the postures in the hysteresis operation with improved accuracy (2.89 and 3.87 mm for the single and the antagonistic-tendons layouts, respectively). The measured accuracy was within the target value of 5 mm for planning of neuroendoscopic resection of intraventricle tumors. The friction in tendons was the most predominant factor for the hysteresis operation in the robot. The extended FKM including this factor can improve prediction accuracy of the postures in the hysteresis operation. The trajectory of the new robot can be planned within target value for the neuroendoscopic procedure by using the extended FKM.

Treatment of acute and closed Achilles tendon ruptures by minimally invasive tenocutaneous suturing.

PubMed

Ding, Wenge; Yan, Weihong; Zhu, Yaping; Liu, Zhiwei

2012-09-01

Achilles tendon rupture is a common injury, and its complications can impair function. Numerous operations have been described for reconstructing the ruptured tendon, but these methods can compromise microcirculation in the tendon and can seriously impair its healing. Suturing with a minimally invasive tenocutaneous technique soon after the rupture and systematic functional exercise can greatly reduce the possibility of complications. Between June 1996 and February 2009, we treated 88 patients (54 males; age range, 21-66 years) with this method. After follow-up ranging from 1-7 years, the mean American Orthopedic Foot and Ankle Society ankle-hind foot score was 95 (range, 90-98), and the maximum length of postoperative scarring was 3 cm. One patient re-ruptured his Achilles tendon one year after surgery in an accident, but after 10 months, the repaired tendon was still intact. In another patient, the nervus suralis was damaged during surgery by piercing the tension suture at the near end, causing postoperative numbness and swelling. The tension suture was quickly removed, and the patient recovered well with conservative treatment. No large irregular scars, such as those sustained during immobilization, were present over the Achilles tendon. Minimally invasive percutaneous suturing can restore the original length and continuity of the Achilles tendon, is minimally invasive, and has fewer postoperative complications than other methods.

[Zwipp Percutaneous Suture of the Achilles Tendon with the Dresden Instruments].

PubMed

Chmielnicki, M; Prokop, A

2016-06-01

Rupture of the Achilles tendon is the most common rupture of a tendon in man. Acute rupture of the Achilles tendon may be treated in a variety of manners, including conservative treatment, open suture and percutaneous suture. Surgical treatment of active patients is recommended, as the risk of re-rupture is greater after non-surgical treatment. The aim of surgery is adequate treatment of Achilles tendon rupture with a low rate of complications, high comfort for patients and fast social and occupational rehabilitation. The indication for surgical treatment of Achilles tendon rupture predominantly includes ruptures in active patients, with the goal of optimal functional rehabilitation. Furthermore, the percutaneous technique protects soft tissue, with a lower rate of wound healing disorders and infection than with open surgical treatment. In our clinic we perform the percutaneous suturing technique with the Dresden instruments. The surgical technique and functional aftercare are shown in a video clip. Between 2007 and 2013, we treated 212 patients with acute Achilles tendon rupture by surgery with the Dresden instruments. There were 7 re-ruptures (3.3 %) and one case of infection within one year of surgery. Percutaneous Achilles tendon suture technique with the Dresden instruments is a safe operation that protects soft tissue. Patient satisfaction is high and the rate of complications is low. This allows rapid social and occupational rehabilitation. Georg Thieme Verlag KG Stuttgart · New York.

Is the Dresden technique a mechanical design of choice suitable for the repair of middle third Achilles tendon ruptures? A biomechanical study.

PubMed

de la Fuente, C; Carreño-Zillmann, G; Marambio, H; Henríquez, H

2016-01-01

To compare the mechanical failure of the Dresden technique for Achilles tendon repair with the double modified Kessler technique controlled repair technique. The maximum resistance of the two repair techniques are also compared. A total of 30 Achilles tendon ruptures in bovine specimens were repaired with an Ethibond(®) suture to 4.5cm from the calcaneal insertion. Each rupture was randomly distributed into one of two surgical groups. After repair, each specimen was subjected to a maximum traction test. The mechanical failure (tendon, suture, or knot) rates (proportions) were compared using the exact Fisher test (α=.05), and the maximum resistances using the Student t test (α=.05). There was a difference in the proportions of mechanical failures, with the most frequent being a tendon tear in the Dresden technique, and a rupture of the suture in the Kessler technique. The repair using the Dresden technique performed in the open mode, compared to the Kessler technique, has a more suitable mechanical design for the repair of middle third Achilles tendon ruptures on developing a higher tensile resistance in 58.7%. However, its most common mechanical failure was a tendon tear, which due to inappropriate loads could lead to lengthening of the Achilles tendon. Copyright © 2016 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

Viscoelastic properties of healthy achilles tendon are independent of isometric plantar flexion strength and cross-sectional area.

PubMed

Suydam, Stephen M; Soulas, Elizabeth M; Elliott, Dawn M; Silbernagel, Karin Gravare; Buchanan, Thomas S; Cortes, Daniel H

2015-06-01

Changes in tendon viscoelastic properties are observed after injuries and during healing as a product of altered composition and structure. Continuous Shear Wave Elastography is a new technique measuring viscoelastic properties of soft tissues using external shear waves. Tendon has not been studied with this technique, therefore, the aims of this study were to establish the range of shear and viscosity moduli in healthy Achilles tendons, determine bilateral differences of these parameters and explore correlations of viscoelasticity to plantar flexion strength and tendon area. Continuous Shear Wave Elastography was performed over the free portion of both Achilles tendons from 29 subjects. Isometric plantar flexion strength and cross sectional area were measured. The average shear and viscous moduli was 83.2 kPa and 141.0 Pa-s, respectively. No correlations existed between the shear or viscous modulus and area or strength. This indicates that viscoelastic properties can be considered novel, independent biomarkers. The shear and viscosity moduli were bilaterally equivalent (p = 0.013, 0.017) which allows determining pathologies through side-to-side deviations. The average bilateral coefficient of variation was 7.2% and 9.4% for shear and viscosity modulus, respectively. The viscoelastic properties of the Achilles tendon may provide an unbiased, non-subjective rating system of tendon recovery and optimizing treatment strategies. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Viscoelastic Properties of Healthy Achilles Tendon are Independent of Isometric Plantar Flexion Strength and Cross-Sectional Area

PubMed Central

Suydam, Stephen M.; Soulas, Elizabeth M.; Elliott, Dawn M.; Silbernagel, Karin Gravare; Buchanan, Thomas S.; Cortes, Daniel H.

2015-01-01

Changes in tendon viscoelastic properties are observed after injuries and during healing as a product of altered composition and structure. Continuous Shear Wave Elastography is a new technique measuring viscoelastic properties of soft tissues using external shear waves. Tendon has not been studied with this technique, therefore, the aims of this study were to establish the range of shear and viscosity moduli in healthy Achilles tendons, determine bilateral differences of these parameters and explore correlations of viscoelasticity to plantar flexion strength and tendon area. Continuous Shear Wave Elastography was performed over the free portion of both Achilles tendons from 29 subjects. Isometric plantar flexion strength and cross sectional area were measured. The average shear and viscous moduli was 83.2kPa and 141.0Pa-s, respectively. No correlations existed between the shear or viscous modulus and area or strength. This indicates that viscoelastic properties can be considered novel, independent biomarkers. The shear and viscosity moduli were bilaterally equivalent (p=0.013,0.017) which allows determining pathologies through side-to-side deviations. The average bilateral coefficient of variation was 7.2% and 9.4% for shear and viscosity modulus, respectively. The viscoelastic properties of the Achilles tendon may provide an unbiased, non-subjective rating system of tendon recovery and optimizing treatment strategies. PMID:25882209

Effectiveness of xenogenous-based bovine-derived platelet gel embedded within a three-dimensional collagen implant on the healing and regeneration of the Achilles tendon defect in rabbits

PubMed Central

Moshiri, Ali; Oryan, Ahmad; Meimandi-Parizi, Abdolhamid; Koohi-Hosseinabadi, Omid

2014-01-01

Background and objective: Tissue engineering is an option in reconstructing large tendon defects and managing their healing and regeneration. We designed and produced a novel xenogeneic-based bovine platelet, embedded it within a tissue-engineered collagen implant (CI) and applied it in an experimentally induced large tendon defect model in rabbits to test whether bovine platelets could stimulate tendon healing and regeneration in vivo. Methods: One hundred twenty rabbits were randomly divided into two experimental and pilot groups. In all the animals, the left Achilles tendon was surgically excised and the tendon edges were aligned by Kessler suture. Each group was then divided into three groups of control (no implant), treated with CI and treated with collagen-platelet implant. The pilot groups were euthanized at 10, 15, 30 and 40 days post-injury (DPI), and their gross and histologic characteristics were evaluated to study host–graft interaction mechanism. To study the tendon healing and its outcome, the experimental animals were tested during the experiment using hematologic, ultrasonographic and various methods of clinical examinations and then euthanized at 60 DPI and their tendons were evaluated by gross pathologic, histopathologic, scanning electron microscopic, biophysical and biochemical methods. Results: Bovine platelets embedded within a CI increased inflammation at short term while it increased the rate of implant absorption and matrix replacement compared with the controls and CI alone. Treatment also significantly increased diameter, density, amount, alignment and differentiation of the collagen fibrils and fibers and approximated the water uptake and delivery behavior of the healing tendons to normal contralaterals (p < 0.05). Treatment also improved echogenicity and homogenicity of the tendons and reduced peritendinous adhesion, muscle fibrosis and atrophy, and therefore, it improved the clinical scores and physical activity related to the injured limb when compared with the controls (p < 0.05). Conclusion: The bovine platelet gel embedded within the tissue-engineered CI was effective in healing, modeling and remodeling of the Achilles tendon in rabbit. This strategy may be a valuable option in the clinical setting. PMID:24840092

Fibrocartilage in tendons and ligaments — an adaptation to compressive load

PubMed Central

BENJAMIN, M.; RALPHS, J. R.

1998-01-01

Where tendons and ligaments are subject to compression, they are frequently fibrocartilaginous. This occurs at 2 principal sites: where tendons (and sometimes ligaments) wrap around bony or fibrous pulleys, and in the region where they attach to bone, i.e. at their entheses. Wrap-around tendons are most characteristic of the limbs and are commonly wider at their point of bony contact so that the pressure is reduced. The most fibrocartilaginous tendons are heavily loaded and permanently bent around their pulleys. There is often pronounced interweaving of collagen fibres that prevents the tendons from splaying apart under compression. The fibrocartilage can be located within fascicles, or in endo- or epitenon (where it may protect blood vessels from compression or allow fascicles to slide). Fibrocartilage cells are commonly packed with intermediate filaments which could be involved in transducing mechanical load. The ECM often contains aggrecan which allows the tendon to imbibe water and withstand compression. Type II collagen may also be present, particularly in tendons that are heavily loaded. Fibrocartilage is a dynamic tissue that disappears when the tendons are rerouted surgically and can be maintained in vitro when discs of tendon are compressed. Finite element analyses provide a good correlation between its distribution and levels of compressive stress, but at some locations fibrocartilage is a sign of pathology. Enthesis fibrocartilage is most typical of tendons or ligaments that attach to the epiphyses of long bones where it may also be accompanied by sesamoid and periosteal fibrocartilages. It is characteristic of sites where the angle of attachment changes throughout the range of joint movement and it reduces wear and tear by dissipating stress concentration at the bony interface. There is a good correlation between the distribution of fibrocartilage within an enthesis and the levels of compressive stress. The complex interlocking between calcified fibrocartilage and bone contributes to the mechanical strength of the enthesis and cartilage-like molecules (e.g. aggrecan and type II collagen) in the ECM contribute to its ability to withstand compression. Pathological changes are common and are known as enthesopathies. PMID:10029181

Intermittent KoldBlue cryotherapy of 3×10 min changes mid‐portion Achilles tendon microcirculation

PubMed Central

Knobloch, Karsten; Grasemann, Ruth; Spies, Marcus; Vogt, Peter M

2007-01-01

Background Neovascularisation and microcirculatory changes have been reported in Achilles tendinopathy. Cryotherapy and compression, as part of a rest, ice, compression and elevation regimen, are shown to decrease pain and improve function. However, the microcirculatory changes following a given dosage of cryotherapy on mid‐portion Achilles tendon remain unclear. Study design Prospective clinical cohort study, level of evidence 2. Methods 30 people (12 males, 33 (SD 12) years, body mass index 25.6 (5.3) kg/m2) were included in the cohort. 3×10 min KoldBlue ankle‐cooling bandages were applied and microcirculation of Achilles tendon mid‐portion was real‐time and continuously assessed using a laser‐Doppler‐spectrophotometry system (O2C, Germany). Results Superficial capillary blood flow was reduced from 42 to 6, 5 and 3 relative units (rU) in the first, second and third cryotherapy periods, respectively (−65%, p = 0.001), with no significant capillary hyperaemia. Deep capillary tendon blood flow was reduced from 180 to 82, 53 and 52 rU (−71%, p = 0.001) within 6–9 min of application without hyperaemia. Superficial tendon oxygen saturation dropped significantly from 43% to 26%, 18% and 11% (p = 0.001) after repetitive cryotherapy, with persisting increase of tendon oxygenation during rewarming (51%, 49% and 54%, p = 0.077) up to 27% of the baseline level. At 8 mm tendon depth, cryotherapy preserved local oxygenation. Relative postcapillary venous tendon filling pressures were favourably reduced from 41 (11) to 31, 28 and 26 rU (−36%, p = 0.001) superficially and from 56 (11) to 45, 46 and 48 rU (−18%, p = 0.001) in deep capillary blood flow during cryotherapy, facilitating capillary venous clearance. Conclusion Intermittent cryotherapy of 3×10 min significantly decreases local Achilles tendon mid‐portion capillary blood flow by 71%. Within 2 min of rewarming, tendon oxygen saturation is re‐established following cryotherapy. Postcapillary venous filling pressures are reduced during cryotherapy, favouring capillary venous outflow of the healthy Achilles tendon. PMID:17138636

Corrosion of post-tensioned tendons with deficient grout : final report.

DOT National Transportation Integrated Search

2016-10-20

Recent corrosion failures of post-tensioned (PT) tendons in the Ringling Causeway Bridge (and corrosion development of PT tendons elsewhere in Florida) utilizing pre-packaged low-bleed specified grout products have spurred the need to evaluate what m...

Achilles Tendon Rupture

MedlinePlus

... also help the muscle and tendon absorb more force and prevent injury. Vary your exercises. Alternate high-impact sports, such as running, with low-impact sports, such as walking, biking or swimming. Avoid activities that place excessive stress on your Achilles tendons, such as hill ...

Effects of plasma rich in growth factors (PRGF) on biomechanical properties of Achilles tendon repair.

PubMed

López-Nájera, Diego; Rubio-Zaragoza, Mónica; Sopena-Juncosa, Joaquín J; Alentorn-Geli, Eduard; Cugat-Bertomeu, Ramón; Fernández-Sarmiento, J Andrés; Domínguez-Pérez, Juan M; García-Balletbó, Montserrat; Primo-Capella, Víctor J; Carrillo-Poveda, José M

2016-12-01

To assess the biomechanical effects of intra-tendinous injections of PRGF on the healing Achilles tendon after repair in a sheep model. Thirty sheep were randomly assigned into one of the six groups depending on the type of treatment received (PRGF or placebo) and survival time (2, 4 and 8 weeks). The Achilles tendon injury was repaired by suturing the tendinous edges employing a three-loop pulley pattern. A trans-articular external fixation system was then used for immobilization. The PRGF or placebo was administered on a weekly basis completing a maximum of three infiltrations. The force, section and tension values were compared between the operated and healthy Achilles tendons across all groups. The PRGF-treated tendons had higher force at 8 weeks compared with the placebo group (p = 0.007). Between 2 and 4 weeks, a significant increase in force in both the PRGF-treated tendon (p = 0.0027) and placebo group (p = 0.0095) occurred. No significant differences were found for section ratio between PRGF-treated tendons and the placebo group for any of the time periods evaluated. At 2 weeks, PRGF-treated tendons had higher tension ratio compared with placebo group tendons (p = 0.0143). Both PRGF and placebo treatments significantly improved the force (p < 0.001 and p = 0.0095, respectively) and tension (p = 0.009 and p = 0.0039, respectively) ratios at 8 weeks compared with 2 weeks. The application of PRGF increases Achilles tendon repair strength at 8 weeks compared with the use of placebo. The use of PRGF does not modify section and tension ratios compared with placebo at 8 weeks. The tension ratio progressively increases between 2 and 8 weeks compared with the placebo.

Application of Computed Tomography Processed by Picture Archiving and Communication Systems in the Diagnosis of Acute Achilles Tendon Rupture

PubMed Central

Tian, Jing; Xie, Bing; Zhang, Hao

2016-01-01

The applications of CT examination in the diagnosis of the acute Achilles tendon rupture (AATR) were investigated. A total of 36 patients with suspected acute Achilles tendon rupture were tested using physical examination, ultrasound, and 3DCT scanning, respectively. Then, surgery was performed for the patients who showed positive result in at least two of the three tests for AATR. 3DVR, MPR, and the other CT scan image processing and diagnosis were conducted in PACS (picture archiving and communication system). PACS was also used to measure the length of distal broken ends of the Achilles tendon (AT) to tendon calcaneal insertion. Our study indicated that CT has the highest accuracy in diagnosis of acute Achilles tendon complete rupture. The length measurement is matched between PACS and those actually measured in operation. CT not only demonstrates more details directly in three dimensions especially with the rupture involved calcaneal insertion flap but also locates the rupture region for percutaneous suture by measuring the length of distal stump in PACS without the effect of the position of ankle. The accuracy of CT diagnosis for Achilles tendon partial rupture is yet to be studied. PMID:28078295

Platelet-rich plasma for rotator cuff repair.

PubMed

Barber, F Alan

2013-12-01

Rotator cuff tears are a common cause of shoulder pain and disability. Because they combine both traumatic and degenerative elements, the surgical repair can be challenging. Even after surgical intervention, tendon residual defects or "retears" often develop. Risk factors for tendon "retears" include patient age, number of tendons involved, tear size, and smoking. Platelet-rich plasma (PRP) is a supraphysiological concentration of platelets, which may be able to positively augment rotator cuff tendon healing. Not all PRPs are the same and those containing higher leukocyte levels may be detrimental to tendon healing. Thrombin activation triggers an immediate release of growth factors from the PRP and may actually inhibit some parts of the healing response. As yet, the clinical data does not conclusively prove a benefit from PRP, but discernment is required in evaluating the published results. As different PRPs may act differently and the results may be dose dependent requiring more PRP to achieve a beneficial threshold. How success is measured (clinical outcomes vs. intact cuff tendons) and how long the patients are followed are also critical items. Currently, the PRP fibrin matrix version holds the greatest promise for improving clinical success after rotator cuff tendon repair.

Tendon Tissue Engineering: Progress, Challenges, and Translation to the Clinic

PubMed Central

Shearn, Jason T.; Kinneberg, Kirsten R.C.; Dyment, Nathaniel A.; Galloway, Marc T.; Kenter, Keith; Wylie, Christopher; Butler, David L.

2013-01-01

The tissue engineering field has made great strides in understanding how different aspects of tissue engineered constructs (TECs) and the culture process affect final tendon repair. However, there remain significant challenges in developing strategies that will lead to a clinically effective and commercially successful product. In an effort to increase repair quality, a better understanding of normal development, and how it differs from adult tendon healing, may provide strategies to improve tissue engineering. As tendon tissue engineering continues to improve, the field needs to employ more clinically relevant models of tendon injury such as degenerative tendons. We need to translate successes to larger animal models to begin exploring the clinical implications of our treatments. By advancing the models used to validate our TECs, we can help convince our toughest customer, the surgeon, that our products will be clinically efficacious. As we address these challenges in musculoskeletal tissue engineering, the field still needs to address the commercialization of products developed in the laboratory. TEC commercialization faces numerous challenges because each injury and patient is unique. This review aims to provide tissue engineers with a summary of important issues related to engineering tendon repairs and potential strategies for producing clinically successful products. PMID:21625053

Relationship between Achilles tendon properties and foot strike patterns in long-distance runners.

PubMed

Kubo, Keitaro; Miyazaki, Daisuke; Tanaka, Shigeharu; Shimoju, Shozo; Tsunoda, Naoya

2015-01-01

The purpose of this study was to investigate the relationship between Achilles tendon properties and foot strike patterns in long-distance runners. Forty-one highly trained male long-distance runners participated in this study. Elongation of the Achilles tendon and aponeurosis of the medial gastrocnemius muscle were measured using ultrasonography, while the participants performed ramp isometric plantar flexion up to the voluntary maximum. The relationship between the estimated muscle force and tendon elongation during the ascending phase was fit to a linear regression, the slope of which was defined as stiffness. In addition, the cross-sectional area of the Achilles tendon was measured using ultrasonography. Foot strike patterns (forefoot, midfoot and rearfoot) during running were determined at submaximal velocity (18 km · h(-1)) on a treadmill. The number of each foot strike runner was 12 for the forefoot (29.3%), 12 for the midfoot (29.3%) and 17 for the rearfoot (41.5%). No significant differences were observed in the variables measured for the Achilles tendon among the three groups. These results suggested that the foot strike pattern during running did not affect the morphological or mechanical properties of the Achilles tendon in long-distance runners.

Effects of a peracetic acid disinfection protocol on the biocompatibility and biomechanical properties of human patellar tendon allografts.

PubMed

Lomas, R J; Jennings, L M; Fisher, J; Kearney, J N

2004-01-01

Patellar tendon allografts, retrieved from cadaveric human donors, are widely used for replacement of damaged cruciate ligaments. In common with other tissue allografts originating from cadaveric donors, there are concerns regarding the potential for disease transmission from the donor to the recipient. Additionally, retrieval and subsequent processing protocols expose the graft to the risk of environmental contamination. For these reasons, disinfection or sterilisation protocols are necessary for these grafts before they are used clinically. A high-level disinfection protocol, utilising peracetic acid (PAA), has been developed and investigated for its effects on the biocompatibility and biomechanics of the patellar tendon allografts. PAA disinfection did not render the grafts either cytotoxic or liable to provoke an inflammatory response as assessed in vitro . However, the protocol was shown to increase the size of gaps between the tendon fibres in the matrix and render the grafts more susceptible to digestion with collagenase. Biomechanical studies of the tendons showed that PAA treatment had no effect on the ultimate tensile stress or Young's modulus of the tendons, and that ultimate strain was significantly higher in PAA treated tendons.

Tissue Engineering Strategies for the Tendon/ligament-to-bone insertion

PubMed Central

Smith, Lester; Xia, Younan; Galatz, Leesa M.; Genin, Guy M.; Thomopoulos, Stavros

2012-01-01

Injuries to connective tissues are painful and disabling and result in costly medical expenses. These injuries often require re-attachment of an unmineralized connective tissue to bone. The uninjured tendon/ligament-to-bone insertion (enthesis) is a functionally graded material that exhibits a gradual transition from soft tissue (i.e., tendon or ligament) to hard tissue (i.e., mineralized bone) through a fibrocartilaginous transition region. This transition is believed to facilitate force transmission between the two dissimilar tissues by ameliorating potentially damaging interfacial stress concentrations. The transition region is impaired or lost upon tendon/ligament injury and is not regenerated following surgical repair or natural healing, exposing the tissue to risk of re-injury. The need to regenerate a robust tendon-to-bone insertion has led a number of tissue engineering repair strategies. This review treats the tendon-to-bone insertion site as a tissue structure whose primary role is mechanical and discusses current and emerging strategies for engineering the tendon/ligament-to-bone insertion in this context. The focus lies on strategies for producing mechanical structures that can guide and subsequently sustain a graded tissue structure and the associated cell populations. PMID:22185608

Modified rerouting procedure for failed peroneal tendon dislocation surgery.

PubMed

Gaulke, R; Hildebrand, F; Panzica, M; Hüfner, T; Krettek, C

2010-04-01

Recurrent dislocation of the peroneal tendons following operative treatment is relatively uncommon, but can be difficult to treat. We asked whether subligamental transposition of the peroneus brevis tendon, fibular grooving, and reattachment of the superior peroneal retinaculum for failed peroneal tendon dislocation surgery would achieve a stable fixation of the peroneal tendons and whether there would be restrictions of ROM or instability of the hindfoot. We reviewed six female patients (mean age, 24.5 years) with general laxity of joints preoperatively and at 6 weeks and 3, 6, and 12 months postoperatively. Within 1 year postoperatively no recurrence was found. In two ankles the extension was restricted 5 degrees to 10 degrees . In another pronation and supination was restricted 5 degrees each. Stability of the ankle increased in four patients and stayed unchanged in two. AOFAS score increased from a mean value of 36 +/- 20.6 preoperatively to 90 +/- 7 postoperatively at 1 year. We conclude transposition of the peroneus brevis tendon is a reasonable treatment for failed peroneal tendon dislocation surgery. Level IV, therapeutic study (prospective case series). See Guidelines for Authors for a complete description of levels of evidence.

Tendon regeneration in human and equine athletes: Ubi Sumus-Quo Vadimus (where are we and where are we going to)?

PubMed

Spaas, Jan H; Guest, Deborah J; Van de Walle, Gerlinde R

2012-10-01

Tendon injuries are one of the most common orthopaedic problems in both human and equine athletes. When a damaged tendon heals naturally, it loses a substantial part of the original strength and elasticity. Therefore, tendons recover structurally (reparation) but not functionally (regeneration) after conservative medical or surgical treatment. Since the structure and matrix composition of human and equine tendons share many similarities, the nature of tendon injuries are also strongly comparable in both species. Therefore, the evaluation of regenerative therapies in horses may have applications for future human medicine and vice versa. The current review focuses briefly on the physiology of human and equine tendon in order to better comprehend the modus operandi of this structure under pathophysiological circumstances. In addition, the reparative effects of conservative medical and surgical interventions are discussed concisely, and an extensive overview is given on the regenerative therapies that are currently being explored. For the latter, the results of equine clinical studies might prove invaluable for gaining additional insights into the treatment of human tendinopathies, since not all of these novel regenerative therapies have been evaluated in humans yet.

[Tenotomy of carpal and digital flexor tendons for correction of congenital neuromyodysplasia in a calf].

PubMed

Sohrt, J T; Heppelmann, M; Rehage, J; Staszyk, C

2013-01-01

In a 7-day-old heifer calf, a bilateral flexural deformity of the forelimbs involving the digital flexor tendons, the suspensory ligament and the ulnar and radial carpal flexor tendons was diagnosed. After 2 weeks of conservative treatment consisting of manual stretching of the legs and the application of splints and wooden blocks, which were glued to the soles and extended beyond the tip of the claws, the right forelimb could be extended sufficiently to allow weight bearing, whereas the left forelimb could be passively extended to only approximately 120°. Therefore, tenotomy of the ulnar carpal flexor tendon, the digital flexor tendons and the suspensory ligament was carried out in the left leg. A support bandage was then applied to the leg for 8 weeks, after which the carpus and fetlock could be completely extended passively. Flexural deformity of the carpus caused by contracture of the carpal flexor tendons was treated by means of a tenotomy of the ulnar carpal flexor tendon proximal to the accessory carpal bone, which allowed preservation of the carpal tunnel and avoided the risk of iatrogenic damage to nerves and the carpal joint capsule.

Rehabilitation of flexor and extensor tendon injuries in the hand: current updates.

PubMed

Howell, Julianne W; Peck, Fiona

2013-03-01

In recent years, a significant amount of research in the field of tendon injury in the hand has contributed to advances in both surgical and rehabilitation techniques. The introduction of early motion has improved tendon healing, reduced complications, and enhanced final outcomes. There is overwhelming evidence to show that carefully devised rehabilitation programs are critical to achieving favourable outcomes. Whatever the type, or level, of flexor or extensor injury, the ultimate goal of both the surgeon and therapist is to protect the repair, modify peritendinous adhesions, promote optimal tendon excursion and preserve joint motion. Early tendon motion regimens are initiated at surgery or within 5 days post repair. Intra-operative information from the surgeon to the therapist is vital to the choice of splint protected position to reduce repair rupture/gap forces, and to commencement of active, or splint controlled, motion for tendon excursion. Decisions should align with the phases of healing, the clinician's observations, frequent range of motion measurements and patient input. Clinical concepts pertinent to early motion rehabilitation decisions are presented by zone of injury for both flexor and extensor tendons during the early phases of healing. Copyright © 2013. Published by Elsevier Ltd.

A novel approach using tendon vibration of the human flexor carpi radialis muscle to study spinal reflexes.

PubMed

Tsang, Kenneth; de Bruin, Hubert; Archambeault, Mark

2008-01-01

Although most muscle spindle investigations have used the cat model and invasive measurement techniques, several investigators have used microneurography to record from the Ia and II fibres in humans during tendon vibration. In these studies the muscle spindle primary endings are stimulated using transverse vibration of the tendon at reflex sub-threshold amplitudes. Others have used low amplitude vibration and the stretch evoked M-wave response to determine reflex properties during both agonist and antagonist voluntary contractions. In the past we have developed a PC based instrument that uses Labview and a linear servomotor to study tendon reflex properties by recording stretch evoked M-wave responses from single tendon taps or electrical stimuli to the afferent nerve. In this paper we describe a further development of this system to provide precise vibrations of the tendon up to 65 Hz with amplitudes up to 4 mm. The resultant M-wave train is extracted from background noise via phase coherent subtractive filtering. Test results from vibrating the human distal flexor carpi radialis tendon at 10 and 30 Hz, for relaxed, slight flexion and slight extension, are also presented.

Tissue-engineering strategies for the tendon/ligament-to-bone insertion.

PubMed

Smith, Lester; Xia, Younan; Galatz, Leesa M; Genin, Guy M; Thomopoulos, Stavros

2012-01-01

Injuries to connective tissues are painful and disabling and result in costly medical expenses. These injuries often require reattachment of an unmineralized connective tissue to bone. The uninjured tendon/ligament-to-bone insertion (enthesis) is a functionally graded material that exhibits a gradual transition from soft tissue (i.e., tendon or ligament) to hard tissue (i.e., mineralized bone) through a fibrocartilaginous transition region. This transition is believed to facilitate force transmission between the two dissimilar tissues by ameliorating potentially damaging interfacial stress concentrations. The transition region is impaired or lost upon tendon/ligament injury and is not regenerated following surgical repair or natural healing, exposing the tissue to risk of reinjury. The need to regenerate a robust tendon-to-bone insertion has led a number of tissue engineering repair strategies. This review treats the tendon-to-bone insertion site as a tissue structure whose primary role is mechanical and discusses current and emerging strategies for engineering the tendon/ligament-to-bone insertion in this context. The focus lies on strategies for producing mechanical structures that can guide and subsequently sustain a graded tissue structure and the associated cell populations.

Effects of PDGF-BB delivery from heparinized collagen sutures on the healing of lacerated chicken flexor tendon in vivo.

PubMed

Younesi, Mousa; Knapik, Derrick M; Cumsky, Jameson; Donmez, Baris Ozgur; He, Ping; Islam, Anowarul; Learn, Greg; McClellan, Philip; Bohl, Michael; Gillespie, Robert J; Akkus, Ozan

2017-11-01

Flexor tendon lacerations are traditionally repaired by using non-absorbable monofilament sutures. Recent investigations have explored to improve the healing process by growth factor delivery from the sutures. However, it is difficult to conjugate growth factors to nylon or other synthetic sutures. This study explores the performance of a novel electrochemically aligned collagen suture in a flexor tendon repair model with and without platelet derived growth factor following complete tendon laceration in vivo. Collagen suture was fabricated via electrochemical alignment process. Heparin was covalently bound to electrochemically aligned collagen sutures (ELAS) to facilitate affinity bound delivery of platelet-derived growth factor-BB (PDGF-BB). Complete laceration of the flexor digitorum profundus in the third digit of the foot was performed in 36 skeletally mature White Leghorn chickens. The left foot was used as the positive control. Animals were randomly divided into three groups: control specimens treated with standard nylon suture (n=12), specimens repaired with heparinated ELAS suture without PDGF-BB (n=12) and specimens repaired with heparinated ELAS suture with affinity bound PDGF-BB (n=12). Specimens were harvested at either 4weeks or 12weeks following tendon repair. Differences between groups were evaluated by the degree of gross tendon excursion, failure load/stress, stiffness/modulus, absorbed energy at failure, elongation/strain at failure. Quantitative histological scoring was performed to assess cellularity and vascularity. Closed flexion angle measurements demonstrated no significant differences in tendon excursion between the study groups at 4 or 12weeks. Biomechanical testing showed that the group treated with PDGF-BB bound heparinated ELAS suture had significantly higher stiffness and failure load (p<0.05) at 12-weeks relative to both heparinated ELAS suture and nylon suture. Similarly, the group treated with PDGF-BB bound suture had significantly higher ultimate tensile strength and Young's modulus (p<0.05) at 12-weeks relative to both ELAS suture and nylon suture. Compared to nylon controls, heparinized ELAS with PDGF-BB improved biomechanics and vascularity during tendon healing by 12-weeks following primary repair. The ability of ELAS to deliver PDGF-BB to the lacerated area of tendon presents investigators with a functional bioinductive platform to improve repair outcomes following flexor tendon repair. A high strength aligned collagen suture was fabricated via linear electrocompaction and heparinized for prolonged delivery of PDFG-BB. When it was used to suture a complete lacerated flexor tendon in a chicken model controlled release of the PDGF-BB improved the strength of treated tendon after 12 weeks compared to tendon sutured with commercial nylon suture. Furthermore, Collagen suture with affinity bound PDGF-BB enhanced the vascularization and remodeling of lacerated tendon when it compare to synthetic nylon suture. Overall, electrocompacted collagen sutures holds potential to improve repair outcome in flexor tendon surgeries by improving repair strength and stiffness, vascularity, and remodeling via sustained delivery of the PDGF-BB. The bioinductive collagen suture introduces a platform for sustained delivery of other growth factors for a wide-array of applications. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Achilles Tendon Rupture: Avoiding Tendon Lengthening during Surgical Repair and Rehabilitation

PubMed Central

Maquirriain, Javier

2011-01-01

Achilles tendon rupture is a serious injury for which the best treatment is still controversial. Its primary goal should be to restore normal length and tension, thus obtaining an optimal function. Tendon elongation correlates significantly with clinical outcome; lengthening is an important cause of morbidity and may produce permanent functional impairment. In this article, we review all factors that may influence the repair, including the type of surgical technique, suture material, and rehabilitation program, among many others. PMID:21966048

Development and Application of a Tendon Prosthesis for Early Functional Restoration of the Hand.

DTIC Science & Technology

1975-09-01

AD-ARSA 323 JEFFERSON MEDICAL COLL PHILADELP HIA PA F/6 6/5 DEVELOFHNT AND APPLICATION OF A TENDON PROSTHESIS FOR EARLY FU--ETCU, SEP 75 .1 M HUNTER...THIS SHEET S LEVELINETR S DEVELOPEN AND APPLICATION OF A TENDON PROSTESIS FOR EARLY FUNCTIONAL RTORATION OF THE HAND DOCUMENT IDENTIFICATION...OF A TENDON PROSTHESIS * (B.l FOR EARLY FUNCTIONAL RESTORATION OF THE HArD ANNUAL REPORT by James M. Hunter, M.D. September 1975 (For the period 1 July

Effects of Postmortem Freezing on Passive Properties of Rabbit Extensor Digtorum Longus Muscle Tendon Complex

DTIC Science & Technology

1993-06-14

AD-A266 429 INSTITUTE REPORT NO. 483 Effects of Postmortem Freezing on Passive Properties of Rabbit Extensor Digtorum Longus Muscle Tendon Complex D...Extensor Digtorum Longus Muscle Tendon Complex -- Paul H. Leitschuh, Tammy J. Doherty, Dean C. Taylor, Daniel E. Brooks, John B. Ryan This document has...ABSTRACT The tensile properties of the extensor digitorum longus muscle tendon unit (EDL MTU) were studied in 16 white male New Zealand rabbits in both

A Biomechanical Simulation of the Effect of the Extrinsic Flexor Muscles on Finger Joint Flexion

DTIC Science & Technology

2001-10-25

vol. 44, pp. 493-504, 1997. [8] A.B. Leger and T.E. Milner, “The effect of eccentric exercise on intrinsic and reflex stiffness in the human hand...line of action of the tendons and the effective moment arms. After a certain point, the FDP tendon became slack, while the FDS tendon remained...link chain with three revolute joints and four links was created to model the index finger. The tendons from the extrinsic flexor muscles were

Clinical Outcomes and Return to Sports in Patients with Chronic Achilles Tendon Rupture after Minimally Invasive Reconstruction with Semitendinosus Tendon Graft Transfer.

PubMed

Usuelli, Federico Giuseppe; D'Ambrosi, Riccardo; Manzi, Luigi; Indino, Cristian; Villafañe, Jorge Hugo; Berjano, Pedro

2017-12-01

Objective  The purpose of the study is to evaluate the clinical results and return to sports in patients undergoing reconstruction of the Achilles tendon after minimally invasive reconstruction with semitendinosus tendon graft transfer. Methods  Eight patients underwent surgical reconstruction with a minimally invasive technique and tendon graft augmentation with ipsilateral semitendinosus tendon for chronic Achilles tendon rupture (more than 30 days after the injury and a gap of >6 cm). Patients were evaluated at a minimum follow-up of 24 months after the surgery through the American Orthopaedic Foot and Ankle Society (AOFAS), the Achilles Tendon Total Rupture Scores (ATRS), the Endurance test, the calf circumference of the operated limb, and the contralateral and the eventual return to sports activity performed before the trauma. Results  The mean age at surgery was 50.5 years. Five men and three women underwent the surgery. The average AOFAS was 92, mean Endurance test was 28.1, and the average ATRS was 87. All patients returned to their daily activities, and six out of eight patients have returned to sports activities prior to the accident (two football players, three runners, one tennis player) at a mean of 7.0 (range: 6.7-7.2) months after the surgery. No patient reported complications or reruptures. Conclusion  Our study confirms encouraging results for the treatment of Achilles tendon rupture with a minimally invasive technique with semitendinosus graft augmentation. The technique can be considered safe and allows patients to return to their sports activity. Level of Evidence  Level IV, therapeutic case series.

Uncovering the cellular and molecular changes in tendon stem/progenitor cells attributed to tendon aging and degeneration.

PubMed

Kohler, Julia; Popov, Cvetan; Klotz, Barbara; Alberton, Paolo; Prall, Wolf Christian; Haasters, Florian; Müller-Deubert, Sigrid; Ebert, Regina; Klein-Hitpass, Ludger; Jakob, Franz; Schieker, Matthias; Docheva, Denitsa

2013-12-01

Although the link between altered stem cell properties and tissue aging has been recognized, the molecular and cellular processes of tendon aging have not been elucidated. As tendons contain stem/progenitor cells (TSPC), we investigated whether the molecular and cellular attributes of TSPC alter during tendon aging and degeneration. Comparing TSPC derived from young/healthy (Y-TSPC) and aged/degenerated human Achilles tendon biopsies (A-TSPC), we observed that A-TSPC exhibit a profound self-renewal and clonogenic deficits, while their multipotency was still retained. Senescence analysis showed a premature entry into senescence of the A-TSPC, a finding accompanied by an upregulation of p16(INK4A). To identify age-related molecular factors, we performed microarray and gene ontology analyses. These analyses revealed an intriguing transcriptomal shift in A-TSPC, where the most differentially expressed probesets encode for genes regulating cell adhesion, migration, and actin cytoskeleton. Time-lapse analysis showed that A-TSPC exhibit decelerated motion and delayed wound closure concomitant to a higher actin stress fiber content and a slower turnover of actin filaments. Lastly, based on the expression analyses of microarray candidates, we suggest that dysregulated cell-matrix interactions and the ROCK kinase pathway might be key players in TSPC aging. Taken together, we propose that during tendon aging and degeneration, the TSPC pool is becoming exhausted in terms of size and functional fitness. Thus, our study provides the first fundamental basis for further exploration into the molecular mechanisms behind tendon aging and degeneration as well as for the selection of novel tendon-specific therapeutical targets. © 2013 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

Effect of Footwear Modifications on Oscillations at the Achilles Tendon during Running on a Treadmill and Over Ground: A Cross-Sectional Study.

PubMed

Meinert, Ilka; Brown, Niklas; Alt, Wilfried

2016-01-01

Achilles tendon injuries are known to commonly occur in runners. During running repeated impacts are transferred in axial direction along the lower leg, therefore possibly affecting the oscillation behavior of the Achilles tendon. The purpose of the present study was to explore the effects of different footwear modifications and different ground conditions (over ground versus treadmill) on oscillations at the Achilles tendon. Oscillations were measured in 20 male runners using two tri-axial accelerometers. Participants ran in three different shoe types on a treadmill and over ground. Data analysis was limited to stance phase and performed in time and frequency space. Statistical comparison was conducted between oscillations in vertical and horizontal direction, between running shoes and between ground conditions (treadmill versus over ground running). Differences in the oscillation behavior could be detected between measurement directions with peak accelerations in the vertical being lower than those in the horizontal direction, p < 0.01. Peak accelerations occurred earlier at the distal accelerometer than at the proximal one, p < 0.01. Average normalized power differed between running shoes (p < 0.01) with harder damping material resulting in higher power values. Little to no power attenuation was found between the two accelerometers. Oscillation behavior of the Achilles tendon is not influenced by ground condition. Differences in shoe configurations may lead to variations in running technique and impact forces and therefore result in alterations of the vibration behavior at the Achilles tendon. The absence of power attenuation may have been caused by either a short distance between the two accelerometers or high stiffness of the tendon. High stiffness of the tendon will lead to complete transmission of the signal along the Achilles tendon and therefore no attenuation occurs.

Effect of tendon tensioning: an in vitro study in porcine extensor tendons.

PubMed

Figueroa, David; Calvo, Rafael; Vaisman, Alex; Meleán, Patricio; Figueroa, Francisco

2010-06-01

Graft tensioning is a controversial issue in anterior cruciate ligament reconstruction (ACLR) that has not achieved consensus between peers. The purpose of this study is to determine if after tensioning tendon length and resistance to maximal load changes. We performed an in vitro study with 50 porcine extensors tendons. The first group (P=25) was tensioned with 80 N (19.97 lb) for 10 min, using an ACL graft preparation board. The second group (C=25) was used as control and was not tensioned. The average initial (groups P and C) and post tensioning tendon length (group C) were measured; the average initial and post tensioning tendon diameter were measured as well. All samples were fixated in a tube-clamp system connected to a tension sensor. The samples were stressed with continuous and progressive tension until ultimate failure at maximum load (UFML) occurs. The initial mean length was: P before tensioning=13.4 mm+/-1.4 mm (range 10.5-16.5); P after tensioning=13.8 mm+/-1.4 mm (range 11.5-16.5); C=13 mm+/-1.35 mm (p=0.005). The mean diameter was: P=5.6 mm (4.5-6); C=5.5 mm (range 4.5-6) (p>0.05). The UFML was: P=189.7 N (114-336); C=229.9 N (143-365) (p=0.029). Tendon tensioning with 80 N for 10 min produced 3% average elongation. These could be beneficial in ACLR since tendon tensioning decreases elongation of the graft after fixation. Regardless, tendon tensioning is not innocuous since it diminishes their resistance when continuously stressed until complete failure occurs.

Dedicated ultrasound speckle tracking to study tendon displacement

NASA Astrophysics Data System (ADS)

Korstanje, Jan-Wiebe H.; Selles, Ruud W.; Stam, Henk J.; Hovius, Steven E. R.; Bosch, Johan G.

2009-02-01

Ultrasound can be used to study tendon and muscle movement. However, quantization is mostly based on manual tracking of anatomical landmarks such as the musculotendinous junction, limiting the applicability to a small number of muscle-tendon units. The aim of this study is to quantify tendon displacement without employing anatomical landmarks, using dedicated speckle tracking in long B-mode image sequences. We devised a dedicated two-dimensional multikernel block-matching scheme with subpixel accuracy to handle large displacements over long sequences. Images were acquired with a Philips iE33 with a 7 MHz linear array and a VisualSonics Vevo 770 using a 40 MHz mechanical probe. We displaced the flexor digitorum superficialis of two pig cadaver forelegs with three different velocities (4,10 and 16 mm/s) over 3 distances (5, 10, 15 mm). As a reference, we manually determined the total displacement of an injected hyperechogenic bullet in the tendons. We automatically tracked tendon parts with and without markers and compared results to the true displacement. Using the iE33, mean tissue displacement underestimations for the three different velocities were 2.5 +/- 1.0%, 1.7 +/- 1.1% and 0.7 +/- 0.4%. Using the Vevo770, mean tissue displacement underestimations were 0.8 +/- 1.3%, 0.6 +/- 0.3% and 0.6 +/- 0.3%. Marker tracking displacement underestimations were only slightly smaller, showing limited tracking drift for non-marker tendon tissue as well as for markers. This study showed that our dedicated speckle tracking can quantify extensive tendon displacement with physiological velocities without anatomical landmarks with good accuracy for different types of ultrasound configurations. This technique allows tracking of a much larger range of muscle-tendon units than by using anatomical landmarks.

Evaluation of the histological and mechanical features of tendon healing in a rabbit model with the use of second-harmonic-generation imaging and tensile testing.

PubMed

Hase, E; Sato, K; Yonekura, D; Minamikawa, T; Takahashi, M; Yasui, T

2016-11-01

This study aimed to evaluate the histological and mechanical features of tendon healing in a rabbit model with second-harmonic-generation (SHG) imaging and tensile testing. A total of eight male Japanese white rabbits were used for this study. The flexor digitorum tendons in their right leg were sharply transected, and then were repaired by intratendinous stitching. At four weeks post-operatively, the rabbits were killed and the flexor digitorum tendons in both right and left legs were excised and used as specimens for tendon healing (n = 8) and control (n = 8), respectively. Each specimen was examined by SHG imaging, followed by tensile testing, and the results of the two testing modalities were assessed for correlation. While the SHG light intensity of the healing tendon samples was significantly lower than that of the uninjured tendon samples, 2D Fourier transform SHG images showed a clear difference in collagen fibre structure between the uninjured and the healing samples, and among the healing samples. The mean intensity of the SHG image showed a moderate correlation (R 2 = 0.37) with Young's modulus obtained from the tensile testing. Our results indicate that SHG microscopy may be a potential indicator of tendon healing.Cite this article: E. Hase, K. Sato, D. Yonekura, T. Minamikawa, M. Takahashi, T. Yasui. Evaluation of the histological and mechanical features of tendon healing in a rabbit model with the use of second-harmonic-generation imaging and tensile testing. Bone Joint Res 2016;5:577-585. DOI: 10.1302/2046-3758.511.BJR-2016-0162.R1. © 2016 Yasui et al.

Increased supraspinatus tendon thickness following fatigue loading in rotator cuff tendinopathy: potential implications for exercise therapy.

PubMed

McCreesh, Karen M; Purtill, Helen; Donnelly, Alan E; Lewis, Jeremy S

2017-01-01

Exercise imparts a load on tendon tissue that leads to changes in tendon properties. Studies suggest that loading immediately reduces tendon thickness, with a loss of this response in symptomatic tendinopathy. No studies investigating the response of tendon dimensions to load for the rotator cuff tendons exist. This study aimed to examine the short-term effect of loading on the thickness of the supraspinatus tendon and acromiohumeral distance those with and without rotator cuff tendinopathy. Participants were 20 painfree controls, and 23 people with painful rotator cuff tendinopathy. Supraspinatus tendon thickness and acromiohumeral distance were measured using ultrasound scans before, and at three time points after loading (1, 6 and 24 hours). Loading involved isokinetic eccentric and concentric external rotation and abduction. There was a significant increase in supraspinatus tendon thickness in the pain group at 1 (7%, ∆=0.38, 95% CI 0.19 to 0.57) and 6 hours (11%, ∆=0.53, 95% CI 0.34 to 0.71), although only the 6 hours difference exceeded minimal detectable difference. In contrast, there was a small non-significant reduction in thickness in controls. The acromiohumeral distance reduced significantly in both groups at 1 hour (controls: ∆=0.64, 95% CI 0.38 to 0.90; pain: ∆=1.1, 95% CI 0.85 to 1.33), with a larger change from baseline in the pain group. Those diagnosed with painful supraspinatus tendinopathy demonstrated increased thickening with delayed return to baseline following loading. Rehabilitation professionals may need to take into account the impact of loading to fatigue when planning rehabilitation programmes.

Increased supraspinatus tendon thickness following fatigue loading in rotator cuff tendinopathy: potential implications for exercise therapy

PubMed Central

McCreesh, Karen M; Purtill, Helen; Donnelly, Alan E; Lewis, Jeremy S

2017-01-01

Background/aim Exercise imparts a load on tendon tissue that leads to changes in tendon properties. Studies suggest that loading immediately reduces tendon thickness, with a loss of this response in symptomatic tendinopathy. No studies investigating the response of tendon dimensions to load for the rotator cuff tendons exist. This study aimed to examine the short-term effect of loading on the thickness of the supraspinatus tendon and acromiohumeral distance those with and without rotator cuff tendinopathy. Methods Participants were 20 painfree controls, and 23 people with painful rotator cuff tendinopathy. Supraspinatus tendon thickness and acromiohumeral distance were measured using ultrasound scans before, and at three time points after loading (1, 6 and 24 hours). Loading involved isokinetic eccentric and concentric external rotation and abduction. Results There was a significant increase in supraspinatus tendon thickness in the pain group at 1 (7%, ∆=0.38, 95% CI 0.19 to 0.57) and 6 hours (11%, ∆=0.53, 95% CI 0.34 to 0.71), although only the 6 hours difference exceeded minimal detectable difference. In contrast, there was a small non-significant reduction in thickness in controls. The acromiohumeral distance reduced significantly in both groups at 1 hour (controls: ∆=0.64, 95% CI 0.38 to 0.90; pain: ∆=1.1, 95% CI 0.85 to 1.33), with a larger change from baseline in the pain group. Conclusion Those diagnosed with painful supraspinatus tendinopathy demonstrated increased thickening with delayed return to baseline following loading. Rehabilitation professionals may need to take into account the impact of loading to fatigue when planning rehabilitation programmes. PMID:29333279

Effect of Footwear Modifications on Oscillations at the Achilles Tendon during Running on a Treadmill and Over Ground: A Cross-Sectional Study

PubMed Central

Meinert, Ilka; Brown, Niklas; Alt, Wilfried

2016-01-01

Background Achilles tendon injuries are known to commonly occur in runners. During running repeated impacts are transferred in axial direction along the lower leg, therefore possibly affecting the oscillation behavior of the Achilles tendon. The purpose of the present study was to explore the effects of different footwear modifications and different ground conditions (over ground versus treadmill) on oscillations at the Achilles tendon. Methods Oscillations were measured in 20 male runners using two tri-axial accelerometers. Participants ran in three different shoe types on a treadmill and over ground. Data analysis was limited to stance phase and performed in time and frequency space. Statistical comparison was conducted between oscillations in vertical and horizontal direction, between running shoes and between ground conditions (treadmill versus over ground running). Results Differences in the oscillation behavior could be detected between measurement directions with peak accelerations in the vertical being lower than those in the horizontal direction, p < 0.01. Peak accelerations occurred earlier at the distal accelerometer than at the proximal one, p < 0.01. Average normalized power differed between running shoes (p < 0.01) with harder damping material resulting in higher power values. Little to no power attenuation was found between the two accelerometers. Oscillation behavior of the Achilles tendon is not influenced by ground condition. Conclusion Differences in shoe configurations may lead to variations in running technique and impact forces and therefore result in alterations of the vibration behavior at the Achilles tendon. The absence of power attenuation may have been caused by either a short distance between the two accelerometers or high stiffness of the tendon. High stiffness of the tendon will lead to complete transmission of the signal along the Achilles tendon and therefore no attenuation occurs. PMID:27010929

Running shoes increase achilles tendon load in walking: an acoustic propagation study.

PubMed

Wearing, Scott C; Reed, Lloyd; Hooper, Sue L; Bartold, Simon; Smeathers, James E; Brauner, Torsten

2014-08-01

Footwear remains a prime candidate for the prevention and rehabilitation of Achilles tendinopathy because it is thought to decrease tension in the tendon through elevation of the heel. However, evidence for this effect is equivocal. This study used an acoustic transmission technique to investigate the effect of running shoes on Achilles tendon loading during barefoot and shod walking. Acoustic velocity was measured in the Achilles tendon of 12 recreationally active males (age, 31 ± 9 yr; height, 1.78 ± 0.06 m; weight, 81.0 ± 16.9 kg) during barefoot and shod walking at matched self-selected speed (3.4 ± 0.7 km·h). Standard running shoes incorporating a 10-mm heel offset were used. Vertical ground reaction force and spatiotemporal parameters were determined with an instrumented treadmill. Axial acoustic velocity in the Achilles tendon was measured using a custom-built ultrasonic device. All data were acquired at a rate of 100 Hz during 10 s of steady-state walking. Statistical comparisons between barefoot and shod conditions were made using paired t-tests and repeated-measure ANOVA. Acoustic velocity in the Achilles tendon was highly reproducible and was typified by two maxima (P1, P2) and minima (M1, M2) during walking. Footwear resulted in a significant increase in step length, stance duration, and peak vertical ground reaction force compared with barefoot walking. Peak acoustic velocity in the Achilles tendon (P1, P2) was significantly higher with running shoes. Peak acoustic velocity in the Achilles tendon was higher with footwear, suggesting that standard running shoes with a 10-mm heel offset increase tensile load in the Achilles tendon. Although further research is required, these findings question the therapeutic role of standard running shoes in Achilles tendinopathy.

Investigation of a tissue engineered tendon model by PS-OCT

NASA Astrophysics Data System (ADS)

Yang, Ying; Ahearne, Mark; Wimpenny, Ian; Guijarro-Leach, Juan; Torbet, Jim

2010-02-01

A few native tissues, such as tendon, skin and eye, possess highly organized collagenous matrices. In particular, the collagen fibers in tendon are organized into a hierarchical and unidirectional format, which gives rise to the high tissuespecific mechanical properties. This organization has been clearly revealed by a conventional polarized light microscope. The newly developed polarization-sensitive optical coherence tomography (PS-OCT) technique allows non-invasive visualization of birefringence images arising from orientated structures in a three dimensional format. Our previous studies of native tendon and tissue engineered tendon by PS-OCT demonstrate that tissue engineered tendon has a far less perfect collagen fiber organization than native tendon even under dynamic culture conditions. The purpose of this study is to use PS-OCT to assess the relationship between the degree of birefringence, collagen concentration and fiber density in model tendon tissues. The model tissue is constructed from an aligned collagen hydrogel and aligned polyester nanofibers. The effects of the diameter and density of the nanofibers and the collagen concentration in the model have been investigated. The alignment of collagen fibrils is induced by application of a high magnetic field during fibrillogenesis while aligned polyester nanofibers are manufactured using the electrospinning technique. It is found that the collagen concentration, the density and size of nanofiber bundles are the key parameters to produce birefringence in OCT images. The perfectly aligned collagen hydrogel with concentration as high as 4 mg/ml does not exhibit a birefringence image until the hydrogel has been compressed and concentrated. Aligned nanofiber bundles have demonstrated marginal birefringence in the absence of the collagen matrix. These studies enhance our understanding of how to control and optimize the parameters in tendon tissue engineering.

Quantitative tissue parameters of Achilles tendon and plantar fascia in healthy subjects using a handheld myotonometer.

PubMed

Orner, Sarah; Kratzer, Wolfgang; Schmidberger, Julian; Grüner, Beate

2018-01-01

The aim of the study was to examine the quantitative tissue properties of the Achilles tendon and plantar fascia using a handheld, non-invasive MyotonPRO device, in order to generate normal values and examine the biomechanical relationship of both structures. Prospective study of a large, healthy sample population. The study sample included 207 healthy subjects (87 males and 120 females) for the Achilles tendon and 176 healthy subjects (73 males and 103 females) for the plantar fascia. For the correlations of the tissue parameters of the Achilles tendon and plantar fascia an intersection of both groups was formed which included 150 healthy subjects (65 males and 85 females). All participants were measured in a prone position. Consecutive measurements of the Achilles tendon and plantar fascia were performed by MyotonPRO device at defined sites. For the left and right Achilles tendons and plantar fasciae all five MyotonPRO parameters (Frequency [Hz], Decrement, Stiffness [N/m], Creep and Relaxation Time [ms]) were calculated of healthy males and females. The correlation of the tissue parameters of the Achilles tendon and plantar fascia showed a significant positive correlation of all parameters on the left as well as on the right side. The MyotonPRO is a feasible device for easy measurement of passive tissue properties of the Achilles tendon and plantar fascia in a clinical setting. The generated normal values of the Achilles tendon and plantar fascia are important for detecting abnormalities in patients with Achilles tendinopathy or plantar fasciitis in the future. Biomechanically, both structures are positively correlated. This may provide new aspects in the diagnostics and therapy of plantar fasciitis and Achilles tendinopathy. Copyright © 2017 Elsevier Ltd. All rights reserved.

Basic Study and Clinical Implications of Left Ventricular False Tendon. Is it Associated With Innocent Murmur in Children or Heart Disease?

PubMed

Sánchez Ferrer, Francisco; Sánchez Ferrer, María Luisa; Grima Murcia, María Dolores; Sánchez Ferrer, Marina; Sánchez del Campo, Francisco

2015-08-01

Left ventricular false tendon is a structure of unknown function in cardiac physiology that was first described anatomically by Turner. This condition may be related to various electrical or functional abnormalities, but no consensus has ever been reached. The purpose of this study was to determine the time of appearance, prevalence and histologic composition of false tendon, as well as its association with innocent murmur in children and with heart disease. The basic research was performed by anatomic dissection of hearts from adult human cadavers to describe false tendon and its histology. The clinical research consisted of echocardiographic study in a pediatric population to identify any relationship with heart disease, innocent murmur in children, or other abnormalities. Fetal echocardiography was performed prenatally at different gestational ages. False tendon was a normal finding in cardiac dissection and was composed of muscle and connective tissue fibers. In the pediatric population, false tendon was present in 83% on echocardiography and showed a statistically significant association only with innocent murmur in children and slower aortic acceleration. The presence of false tendon was first observed on fetal echocardiography from week 20 of pregnancy. Left ventricular false tendon is a normal finding visualized by fetal echocardiography from week 20 and is present until adulthood with no pathologic effects except for innocent murmur during childhood. It remains to be determined if false tendon is the cause of the murmurs or if its absence or structural anomalies are related to disease. Copyright © 2014 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Exercise-related alterations in crimp morphology in the central regions of superficial digital flexor tendons from young thoroughbreds: a controlled study.

PubMed

Patterson-Kane, J C; Wilson, A M; Firth, E C; Parry, D A; Goodship, A E

1998-01-01

Injury to the core of the mid-metacarpal region of the superficial digital flexor tendon in Thoroughbred racehorses is a very frequent but poorly understood condition. It has been suggested that subclinical changes induced by galloping exercise weaken the collagen in this region of the tendon, predisposing it to rupture. The longitudinally arranged collagen fibrils in tendon follow a planar waveform, termed the crimp. Fibril bundles with a smaller crimp angle fail at a lower level of strain than those with a larger crimp angle. This study tested the hypothesis that a specific 18 month exercise programme would result in significant reduction of collagen fibril crimp angle and period length in the core region of the superficial digital flexor tendon of young Thoroughbreds (21 +/- 1 months), compared to the normal change in these parameters with age. Central region crimp angle and length were significantly lower in exercised horses than in control horses (P < 0.05). The crimp angle was significantly lower in this central region than in the peripheral region of the tendon in 4 of the 5 exercised horses, as was the crimp length in 3 of the 4 horses. The crimp angle in the peripheral region was significantly greater in exercised horses than in the controls (P < 0.05), which may indicate functional adaptation due to differing mechanical environment between the 2 tendon regions. The results of this study supported previous evidence that galloping exercise modifies normal age-related changes in crimp morphology in the core of the superficial digital flexor tendon. Such changes are indicative of microtrauma and would be detrimental to tendon strength.

Functional grading of mineral and collagen in the attachment of tendon to bone.

PubMed

Genin, Guy M; Kent, Alistair; Birman, Victor; Wopenka, Brigitte; Pasteris, Jill D; Marquez, Pablo J; Thomopoulos, Stavros

2009-08-19

Attachment of dissimilar materials is a major challenge because high levels of localized stress may develop at their interfaces. An effective biologic solution to this problem exists at one of nature's most extreme interfaces: the attachment of tendon (a compliant, structural "soft tissue") to bone (a stiff, structural "hard tissue"). The goal of our study was to develop biomechanical models to describe how the tendon-to-bone insertion derives its mechanical properties. We examined the tendon-to-bone insertion and found two factors that give the tendon-to-bone transition a unique grading in mechanical properties: 1), a gradation in mineral concentration, measured by Raman spectroscopy; and 2), a gradation in collagen fiber orientation, measured by polarized light microscopy. Our measurements motivate a new physiological picture of the tissue that achieves this transition, the tendon-to-bone insertion, as a continuous, functionally graded material. Our biomechanical model suggests that the experimentally observed increase in mineral accumulation within collagen fibers can provide significant stiffening of the partially mineralized fibers, but only for concentrations of mineral above a "percolation threshold" corresponding to formation of a mechanically continuous mineral network within each collagen fiber (e.g., the case of mineral connectivity extending from one end of the fiber to the other). Increasing dispersion in the orientation distribution of collagen fibers from tendon to bone is a second major determinant of tissue stiffness. The combination of these two factors may explain the nonmonotonic variation of stiffness over the length of the tendon-to-bone insertion reported previously. Our models explain how tendon-to-bone attachment is achieved through a functionally graded material composition, and provide targets for tissue engineered surgical interventions and biomimetic material interfaces.

[Tendinosis and ruptures of the Achilles tendon].

PubMed

Amlang, M H; Zwipp, H

2012-02-01

Tendinosis of the Achilles tendon is a degenerative-reparative structural change of the tendon with microdefects, increases in cross-section due to cicatricial tendon regeneration, neoangiogenesis and reduction of elasticity. The previously used term tendinitis is only rarely used for the chronic form since signs of inflammation such as redness and hyperthermia or elevated levels of inflammatory parameters on laboratory testing are generally absent. Duplex sonography with visualization of the neovascularization has become a valuable supplement not only for diagnostics but also for therapy planning. The classic, conservative therapy for painful tendinosis consists of oral anti-inflammatory drugs, pain-adapted load reduction, raising the heel, stretching the calf musculature, and various physiotherapeutic interventions. When conservative treatment over a period of 4 - 6 months fails to produce any or non-adequate pain relief, an indication for surgical treatment should be considered. In the therapy for fresh ruptures of the Achilles tendon further developments in minimally invasive techniques have led to a worldwide paradigm change over the past 10 years. The decisive advantage of minimally invasive surgical techniques is the lower risk of wound infection as compared to the sutures of the open technique. When compared with conservative functional therapy the minimally invasive repair has the advantage of being less dependent on the compliance of the patient since, in the early phase of tendon healing the suture prevents a separation of the tendon ends upon controlled movements. However, not every patient with a ruptured Achilles tendon should be treated with a minimally invasive repair. Open tendon reconstruction and functional conservative therapy are still justified when the correct indication is given. © Georg Thieme Verlag KG Stuttgart · New York.

Genomic and lipidomic actions of nandrolone on detached rotator cuff muscle in sheep.

PubMed

Flück, Martin; Ruoss, Severin; Möhl, Christoph B; Valdivieso, Paola; Benn, Mario C; von Rechenberg, Brigitte; Laczko, Endre; Hu, Junmin; Wieser, Karl; Meyer, Dominik C; Gerber, Christian

2017-01-01

Reversal of fatty infiltration of pennate rotator cuff muscle after tendon release is hitherto impossible. The administration of nandrolone starting at the time of tendon release prevents the increase in fat content, but does not revert established fatty infiltration. We hypothesised that tendon release and myotendinous retraction cause alterations in lipid related gene expression leading to fatty muscle infiltration, which can be suppressed by nandrolone through its genomic actions if applied immediately after tendon release. The effects of infraspinatus tendon release and subsequent tendon repair at 16 weeks were studied in six Swiss Alpine sheep. In the interventional groups, 150mg nandrolone was administered weekly after tendon release until sacrifice (N22W, n=6) or starting at the time of repair (N6W, n=6). Infraspinatus volume, composition, expressed transcripts, lipids, and selected proteins were analyzed at baseline, 16 and 22 weeks. Tendon release reduced infraspinatus volume by 22% and increased fat content from 11% to 38%. These changes were not affected by repair. Fatty infiltration was associated with up-regulation of 227 lipid species, and increased levels of the adipocyte differentiation marker PPARG2 (peroxisome proliferator-activated receptor gamma 2). Nandrolone abrogated lipid accumulation, halved the loss in fiber area percentage, and up-regulated androgen receptor levels and transcript expression in the N22W but not the N6W group. The results document that nandrolone mitigates muscle-to-fat transformation after tendon release via a general down-regulation of lipid accumulation concomitantly with up-regulated expression of its nuclear receptor and downstream transcripts in skeletal muscle. Reduced responsiveness of retracted muscle to nandrolone as observed in the N6W group is reflected by a down-regulated transcript response. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Etiology and pathophysiology of tendon ruptures in sports.

PubMed

Kannus, P; Natri, A

1997-04-01

Of all spontaneous tendon ruptures, complete Achilles tendon tears are most closely associated with sports activities (1-3). Schönbauer (3) reported that 75% of all ruptures of the Achilles tendon are related to sports. In Plecko & Passl (2) the number was 60%. In our material of 430 cases, the number of sports-related Achilles ruptures was very similar (62%), while only 2% of ruptures of other tendons were sports-related (P < 0.001) (1). Also, the majority of Achilles reruptures occurred in sports. The ruptures occurred most often in soccer (34%), track and field (16%) and basketball (14%). The distribution of Achilles ruptures according to different sports varies considerably from country to country, according to the national sport traditions. For example, in northern and middle Europe, soccer, tennis, track and field, indoor ball games, downhill skiing, and gymnastics are the most common; and in North America, football, basketball, baseball, tennis and downhill skiing dominate the statistics (1, 2, 4). In sports, some Achilles ruptures are not spontaneous or degeneration-induced but may occur as a consequence of the remarkably high forces that are involved in the performance (2). Ruptures in the high jump or triple jump are good examples. In such cases, failure in the neuromuscular protective mechanisms due to fatigue or disturbed co-ordination can frequently be found. The spontaneous complete rupture of the supraspinatus tendon of the rotator cuff does not occur very frequently in sports. Those sports that include high-energy throwing movements, such as American and Finnish baseball, American football, rugby and discuss and javelin throwing, may, however, produce this injury. Partial tears and inflammations of the rotator cuff complex are much more frequent in throwing sports. The complete rupture of the proximal long head of the biceps brachii tendon is rare among competitive and recreational athletes. In our material, under 2% of these ruptures were associated with sports activities (5). The rupture (avulsion) of the distal tendon of the biceps muscle is rare. In sports, gymnastics, body building and weight lifting have been said to be able to produce this injury (6). In general, complete ruptures of the quadriceps tendon and the patellar tendon occur most often in older individuals. In our study, the mean age of these patients was 65 years (5). However, these injuries do also occur in younger age groups, especially in athletes. In athletes, the rupture most frequently occurs in high-power sports events, such as high jump, basketball and weight lifting, at the age of 15-30 years. A chronic-patellar apicitis (jumper's knee) may predispose rupture of the tendon (7). As is the case with the rotator cuff complex, overuse inflammation and partial tears of the quadriceps and patellar tendons are one of the most characteristic athletic injuries. Complete spontaneous ruptures of other tendons in sports are rare, although the literature does provide case studies from almost every tendon the human body possesses (8-18).

Risk of Revision Was Not Reduced by a Double-bundle ACL Reconstruction Technique: Results From the Scandinavian Registers.

PubMed

Aga, Cathrine; Kartus, Jüri-Tomas; Lind, Martin; Lygre, Stein Håkon Låstad; Granan, Lars-Petter; Engebretsen, Lars

2017-10-01

Double-bundle anterior cruciate ligament (ACL) reconstruction has demonstrated improved biomechanical properties and moderately better objective outcomes compared with single-bundle reconstructions. This could make an impact on the rerupture rate and reduce the risk of revisions in patients undergoing double-bundle ACL reconstruction compared with patients reconstructed with a traditional single-bundle technique. The National Knee Ligament Registers in Scandinavia provide information that can be used to evaluate the revision outcome after ACL reconstructions. The purposes of the study were (1) to compare the risk of revision between double-bundle and single-bundle reconstructions, reconstructed with autologous hamstring tendon grafts; (2) to compare the risk of revision between double-bundle hamstring tendon and single-bundle bone-patellar tendon-bone autografts; and (3) to compare the hazard ratios for the same two research questions after Cox regression analysis was performed. Data collection of primary ACL reconstructions from the National Knee Ligament Registers in Denmark, Norway, and Sweden from July 1, 2005, to December 31, 2014, was retrospectively analyzed. A total of 60,775 patients were included in the study; 994 patients were reconstructed with double-bundle hamstring tendon grafts, 51,991 with single-bundle hamstring tendon grafts, and 7790 with single-bundle bone-patellar tendon-bone grafts. The double-bundle ACL-reconstructed patients were compared with the two other groups. The risk of revision for each research question was detected by the risk ratio, hazard ratio, and the corresponding 95% confidence intervals. Kaplan-Meier analysis was used to estimate survival at 1, 2, and 5 years for the three different groups. Furthermore, a Cox proportional hazard regression model was applied and the hazard ratios were adjusted for country, age, sex, meniscal or chondral injury, and utilized fixation devices on the femoral and tibial sides. There were no differences in the crude risk of revision between the patients undergoing the double-bundle technique and the two other groups. A total of 3.7% patients were revised in the double-bundle group (37 of 994 patients) versus 3.8% in the single-bundle hamstring tendon group (1952 of 51,991; risk ratio, 1.01; 95% confidence interval (CI), 0.73-1.39; p = 0.96), and 2.8% of the patients were revised in the bone-patellar tendon-bone group (219 of the 7790 bone-patellar tendon-bone patients; risk ratio, 0.76; 95% CI, 0.54-1.06; p = 0.11). Cox regression analysis with adjustment for country, age, sex, menisci or cartilage injury, and utilized fixation device on the femoral and tibial sides, did not reveal any further difference in the risk of revision between the single-bundle hamstring tendon and double-bundle hamstring tendon groups (hazard ratio, 1.18; 95% CI, 0.85-1.62; p = 0.33), but the adjusted hazard ratio showed a lower risk of revision in the single-bundle bone-patellar tendon-bone group compared with the double-bundle group (hazard ratio, 0.62; 95% CI, 0.43-0.90; p = 0.01). Comparisons of the graft revision rates reported separately for each country revealed that double-bundle hamstring tendon reconstructions in Sweden had a lower hazard ratio compared with the single-bundle hamstring tendon reconstructions (hazard ratio, 1.00 versus 1.89; 95% CI, 1.09-3.29; p = 0.02). Survival at 5 years after index surgery was 96.0% for the double-bundle group, 95.4% for the single-bundle hamstring tendon group, and 97.0% for the single-bundle bone-patellar tendon-bone group. Based on the data from all three national registers, the risk of revision was not influenced by the reconstruction technique in terms of using single- or double-bundle hamstring tendons, although national differences in survival existed. Using bone-patellar tendon-bone grafts lowered the risk of revision compared with double-bundle hamstring tendon grafts. These findings should be considered when deciding what reconstruction technique to use in ACL-deficient knees. Future studies identifying the reasons for graft rerupture in single- and double-bundle reconstructions would be of interest to understand the findings of the present study. Level III, therapeutic study.

[Flexor tendon repair: a short story].

PubMed

Moutet, F; Corcella, D; Forli, A; Mesquida, V

2014-12-01

This short story of flexor tendon repair aims to illustrate hesitations and wanderings of this surgery. Obviously tendon repair was very early considered, but it developed and diffused rather lately. It became a routine practice only in 20th century. This was due on the one hand, in Occident, to the Galen's dogmatic interdiction, on the other hand, to the repair difficulties of this paradoxical structure. Actually tendon is made of fibroblasts and collagen (sticky substances), and then its only goal is to move. According to this necessity, whatever the used techniques are, gliding is the final purpose. Technical evolutions are illustrated by historical contributions to flexor tendon surgery of several "giants" of hand surgery. Copyright © 2014 Elsevier Masson SAS. All rights reserved.