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Sample records for tendons structural

  1. Structure and function of tuna tail tendons.

    PubMed

    Shadwick, Robert E; Rapoport, H Scott; Fenger, Joelle M

    2002-12-01

    The caudal tendons in tunas and other scombrid fish link myotomal muscle directly to the caudal fin rays, and thus serve to transfer muscle power to the hydrofoil-like tail during swimming. These robust collagenous tendons have structural and mechanical similarity to tendons found in other vertebrates, notably the leg tendons of terrestrial mammals. Biochemical studies indicate that tuna tendon collagen is composed of the (alpha1)(2),alpha2 heterotrimer that is typical of vertebrate Type I collagen, while tuna skin collagen has the unusual alpha1,alpha2,alpha3 trimer previously described in the skin of some other teleost species. Tuna collagen, like that of other fish, has high solubility due to the presence of an acid-labile intermolecular cross-link. Unlike collagen in mammalian tendons, no differences related to cross-link maturation were detected among tendons in tuna ranging from 0.05 to 72 kg (approx. 0.25-6 years). Tendons excised post-mortem were subjected to load cycling to determine the modulus of elasticity and resilience (mean of 1.3 GPa and 90%, respectively). These material properties compare closely to those of leg tendons from adult mammals that can function as effective biological springs in terrestrial locomotion, but the breaking strength is substantially lower. Peak tendon forces recorded during steady swimming appear to impose strains of much less than 1% of tendon length, and no more than 1.5% during bursts. Thus, the caudal tendons in tunas do not appear to function as elastic storage elements, even at maximal swimming effort.

  2. 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.

  3. Is higher serum cholesterol associated with altered tendon structure or tendon pain? A systematic review

    PubMed Central

    Tilley, Benjamin J; Cook, Jill L; Docking, Sean I; Gaida, James E

    2015-01-01

    Background Tendon pain occurs in individuals with extreme cholesterol levels (familial hypercholesterolaemia). It is unclear whether the association with tendon pain is strong with less extreme elevations of cholesterol. Objective To determine whether lipid levels are associated with abnormal tendon structure or the presence of tendon pain. Methods We conducted a systematic review and meta-analysis. Relevant articles were found through an electronic search of 6 medical databases—MEDLINE, Cochrane, AMED, EMBASE, Web of Science and Scopus. We included all case–control or cross-sectional studies with data describing (1) lipid levels or use of lipid-lowering drugs and (2) tendon structure or tendon pain. Results 17 studies (2612 participants) were eligible for inclusion in the review. People with altered tendon structure or tendon pain had significantly higher total cholesterol, low-density lipoprotein cholesterol and triglycerides, as well as lower high-density lipoprotein cholesterol; with mean difference values of 0.66, 1.00, 0.33, and −0.19 mmol/L, respectively. Conclusions The results of this review indicate that a relationship exists between an individual’s lipid profile and tendon health. However, further longitudinal studies are required to determine whether a cause and effect relationship exists between tendon structure and lipid levels. This could lead to advancement in the understanding of the pathoaetiology and thus treatment of tendinopathy. PMID:26474596

  4. 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

  5. Seismic response control of frame structure braced with SMA tendons

    NASA Astrophysics Data System (ADS)

    Yan, Shi; Song, Gangbing; Huo, Linsheng; Gu, Haichang

    2007-04-01

    This paper presents studies of seismic response control of a frame structure braced with SMA (Shape Memory Alloy) tendons through both numerical and experimental approaches. Based on the Brinson one-dimensional constitutive law for SMAs, a two-story frame structure braced diagonally with SMA tendons is used as an example to simulate numerically the vibration control process. By considering the temperature, different initial states and thermal properties of the SMA tendon, and the variable intensity and frequency of earthquake input, the parameters of the system were analyzed during the numerically simulation. The time histories of the displacement and hysteretic loops of the SMA tendons were simulated under earthquake ground motion by using finite element method (FEM). To validate the efficiency of the simulation, a shaking table test for the frame structure was conducted. Both numerical simulation and experimental results show that the actively controlled martensite SMA tendons can effectively suppress the vibration of the multi-story frame structure during an earthquake.

  6. Structural and mechanical integrity of tendon-to-tendon attachments used in upper limb tendon transfer surgery.

    PubMed

    Tsiampa, Vassiliki A; Ignatiadis, Ioannis; Papalois, Apostolos; Givissis, Panayiotis; Christodoulou, Anastasios; Fridén, Jan

    2012-09-01

    Improved tendon-to-tendon suturing techniques allow for consistent and immediate activation of transferred muscle after surgery. A pre-requisite for early training after tendon transfer surgery is sufficient mechanical integrity of the tendon-to-tendon attachment. This in vitro study compared the mechanisms and magnitudes of load-to-failure response of two different repair techniques (side-to-side running, n = 7) and weave sutures (n = 8) in sheep front foot tendons. Tensile tests were performed by placing pre-conditioned tendons in a testing machine and stretching at a constant speed to failure. The length of the tendons overlap was the same (50 mm) for both repair techniques. The results of the load to failure tests showed that the side-to-side repairs were significantly stronger than the weave repairs. The failure mechanisms were also different. While the side-to-side attachment failed by longitudinal separation of tendon material of the donor tendon but with the fibres locked to the running sutures attached to the recipient tendon, the weave repairs failed by knot slipping or by suture pullout from the tendon substance. It is concluded that use of the side-to-side repair technique can provide early active training of new motors that not only prevent the formation of adhesions but also facilitate the voluntary recruitment of motors powering new functions before immobilisation-related swelling and stiffness restrain muscle contractions.

  7. 77 FR 69508 - Inservice Inspection of Prestressed Concrete Containment Structures With Grouted Tendons

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-19

    ... COMMISSION Inservice Inspection of Prestressed Concrete Containment Structures With Grouted Tendons AGENCY... Concrete Containment Structures with Grouted Tendons.'' This guide describes a method that the NRC staff considers acceptable for use in developing an appropriate surveillance program for prestressed...

  8. Structural deterioration of tendon collagen in genetic muscular dystrophy.

    PubMed

    Stinson, R H

    1975-08-19

    The structure of gastrocnemius tendons from chickens with genetically induced muscular dystrophy has been studied by low-angle X-ray diffraction. Compared with normal samples there is poor alignment of collagen within the tendons. This difference is quite pronounced at eight weeks when the affected birds are still in comparatively good physical condition. Similar changes have been reported for birds with nutritionally induced muscular dystrophy (Bartlett, M. W., Egelstaff, P. A., Holden, T. M., Stinson, R. H. and Sweeny, P. R. (1973) Biochim. Biophys. Acta 328, 213-220).

  9. Structure-function considerations of muscle-tendon junctions.

    PubMed

    Trotter, John A

    2002-12-01

    Skeletal muscle cells transmit force across the cell membrane to the extracellular matrix and ultimately to tendons. Force transmission may occur both along the lateral surfaces of muscle fibers and at their ends. Forces within muscles may follow the path of greatest resistance. Sites of force transmission are morphologically and compositionally specialized for this function. They are also specialized to provide stress-information that feeds into the synthetic programs of the muscle cell. A detailed analysis of the structures and functions of muscle-tendon junctions is essential to a comprehensive understanding of the way in which muscles and their connective tissues are controlled to move joints and to respond to mechanical stresses.

  10. Tendon's ultrastructure.

    PubMed

    Tresoldi, Ilaria; Oliva, Francesco; Benvenuto, Monica; Fantini, Massimo; Masuelli, Laura; Bei, Roberto; Modesti, Andrea

    2013-01-01

    The structure of a tendon is an important example of complexity of ECM three-dimensional organization. The extracellular matrix (ECM) is a macromolecular network with both structural and regulatory functions. ECM components belong to four major types of macromolecules: the collagens, elastin, proteoglycans, and noncollagenous glycoproteins. Tendons are made by a fibrous, compact connective tissue that connect muscle to bone designed to transmit forces and withstand tension during muscle contraction. Here we show the ultrastructural features of tendon's components.

  11. The Mechanical, Structural, and Compositional Changes of Tendon Exposed to Elastase.

    PubMed

    Grant, Tyler M; Yapp, Clarence; Chen, Qi; Czernuszka, Jan T; Thompson, Mark S

    2015-10-01

    The mechanical response of tendon is dependent on the interaction of structural molecules that constitute the extracellular matrix. However, little is known about the role of elastic fibers that are present in this structure. Elastase treatments have been used to elucidate the mechanical role of elastic fibers in numerous tissues. Here, we show that a standard elastase treatment affects the mechanical properties of tendon, including the ultimate tensile strength and failure strain. Moreover, elastase-treated specimens exhibit significant structural and compositional changes including crimp undulation and release of glycosaminoglycans. These data demonstrate that a common elastase treatment has a complex digestion profile that influences the structure-function relationship of tendon. Thus, defining the mechanical role of elastic fibers in tendon using this technique is challenging. This introduces new and exciting questions regarding the function of elastic fibers in tendon, which may not be as well understood as previously thought.

  12. Effect of prostaglandin E2 injection on the structural properties of the rat patellar tendon

    PubMed Central

    2012-01-01

    Background Increased tendon production of the inflammatory mediator prostaglandin E2 (PGE2) has been suggested to be a potential etiologic agent in the development of tendinopathy. Repeated injection of PGE2 into tendon has been proposed as a potential animal model for studying treatments for tendinopathy. In contrast, nonsteroidal anti-inflammatory drugs (NSAIDs) which inhibit PGE2 production and are commonly prescribed in treating tendinopathy have been shown to impair the healing of tendon after acute injury in animal models. The contradictory literature suggests the need to better define the functional effects of PGE2 on tendon. Our objective was to characterize the effects of PGE2 injection on the biomechanical and biochemical properties of tendon and the activity of the animals. Our hypothesis was that weekly PGE2 injection to the rat patellar tendon would lead to inferior biomechanical properties. Methods Forty rats were divided equally into four groups. Three groups were followed for 4 weeks with the following peritendinous injection procedures: No injection (control), 4 weekly injections of saline (saline), 4 weekly injections of 800 ng PGE2 (PGE2-4 wks). The fourth group received 4 weekly injections of 800 ng PGE2 initially and was followed for a total of 8 weeks. All animals were injected bilaterally. The main outcome measurements included: the structural and material properties of the patellar tendon under tensile loading to failure, tendon collagen content, and weekly animal activity scores. Results The ultimate load of PGE2-4 wks tendons at 4 weeks was significantly greater than control or saline group tendons. The stiffness and elastic modulus of the PGE2 injected tendons at 8 weeks was significantly greater than the control or saline tendons. No differences in animal activity, collagen content, or mean fibril diameter were observed between groups. Conclusions Four weekly peritendinous injections of PGE2 to the rat patellar tendon were not found to

  13. Are Sport-Specific Profiles of Tendon Stiffness and Cross-Sectional Area Determined by Structural or Functional Integrity?

    PubMed Central

    Rieder, Florian; Kösters, Alexander; Müller, Erich; Seynnes, Olivier R.

    2016-01-01

    The present study aimed to determine whether distinct sets of tendon properties are seen in athletes engaged in sports with contrasting requirements for tendon function and structural integrity. Patellar and Achilles tendon morphology and force-deformation relation were measured by combining ultrasonography, electromyography and dynamometry in elite ski jumpers, distance runners, water polo players and sedentary individuals. Tendon cross-sectional area normalized to body mass2/3 was smaller in water polo players than in other athletes (patellar and Achilles tendon; -28 to -24%) or controls (patellar tendon only; -9%). In contrast, the normalized cross-sectional area was larger in runners (patellar tendon only; +26%) and ski jumpers (patellar and Achilles tendon; +21% and +13%, respectively) than in controls. Tendon stiffness normalized to body mass2/3 only differed in ski jumpers, compared to controls (patellar and Achilles tendon; +11% and +27%, respectively) and to water polo players (Achilles tendon only; +23%). Tendon size appears as an adjusting variable to changes in loading volume and/or intensity, possibly to preserve ultimate strength or fatigue resistance. However, uncoupled morphological and mechanical properties indicate that functional requirements may also influence tendon adaptations. PMID:27362657

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

    PubMed Central

    Zellers, Jennifer A.; Cortes, Daniel H.

    2016-01-01

    Introduction 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). Subject Description The subject is a 26 year-old, female basketball coach who sustained an Achilles tendon rupture and was managed non-surgically. Outcome 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. Discussion This case report

  15. The influence of physical activity during youth on structural and functional properties of the Achilles tendon.

    PubMed

    Lenskjold, A; Kongsgaard, M; Larsen, J O; Nielsen, R H; Kovanen, V; Aagaard, P; Kjaer, M; Magnusson, S P

    2015-02-01

    Achilles tendinopathy is a highly prevalent sports injury. Animal studies show a growth response in tendons in response to loading in the immature phase but not after puberty maturation. The aim of this investigation was to examine the structural and material properties in long distance runners who were either physically active (HAY) or inactive (LAY) in young age. Twelve men in HAY group and eight men in LAY group participated. Structural, functional, and biochemical properties of Achilles tendon were estimated from magnetic resonance imaging, ultrasound video recordings, mechanical tests, and tendon biopsies, respectively. There was no difference between the groups with respect to tendon cross-sectional area or tendon free length. There was no difference between the groups with respect to maximal force or mechanical properties. The collagen content, enzymatic and nonenzymatic cross-link density did not differ between the groups, nor did collagen fibril density, diameter, and area. There was a correlation between age and pentosidine/collagen within the groups [(HAY: P < 0.05 and r(2) = 0.47) and (LAY: P < 0.05 and r(2) = 0.52)]. The data suggest that high or low activity during youth did not appreciably influence the mechanical, structural, or biochemical properties of the Achilles tendon in adult long distance runners.

  16. Structural and biomechanical changes in the Achilles tendon after chronic treatment with statins.

    PubMed

    de Oliveira, L P; Vieira, C P; Guerra, F D; Almeida, M S; Pimentel, E R

    2015-03-01

    Cases of tendinopathy and tendon ruptures have been reported as side effects associated with statin therapy. This work assessed possible changes in the structural and biomechanical properties of the tendons after chronic treatment with statins. Wistar rats were divided into the following groups: treated with atorvastatin (A-20 and A-80), simvastatin (S-20 and S-80) and the group that received no treatment (C). The doses of statins were calculated using allometric scaling, based on the doses of 80 mg/day and 20 mg/day recommended for humans. The morphological aspect of the tendons in A-20, S-20 and S-80 presented signals consistent with degeneration. Both the groups A-80 and S-80 showed a less pronounced metachromasia in the compression region of the tendons. Measurements of birefringence showed that A-20, A-80 and S-80 groups had a lower degree of organization of the collagen fibers. In all of the groups treated with statins, the thickness of the epitenon was thinner when compared to the C group. In the biomechanical tests the tendons of the groups A-20, A-80 and S-20 were less resistant to rupture. Therefore, statins affected the organization of the collagen fibers and decreased the biomechanical strength of the tendons, making them more predisposed to ruptures.

  17. Nonlinear ultrasonic guided waves for stress monitoring in prestressing tendons for post-tensioned concrete structures

    NASA Astrophysics Data System (ADS)

    Bartoli, Ivan; Nucera, Claudio; Srivastava, Ankit; Salamone, Salvatore; Phillips, Robert; Lanza di Scalea, Francesco; Coccia, Stefano; Sikorsky, Charles S.

    2009-03-01

    Many bridges, including 90% of the California inventory, are post-tensioned box-girders concrete structures. Prestressing tendons are the main load-carrying components of these and other post-tensioned structures. Despite their criticality, much research is needed to develop and deploy techniques able to provide real-time information on the level of prestress in order to detect dangerous stress losses. In collaboration with Caltrans, UCSD is investigating the combination of ultrasonic guided waves and embedded sensors to provide both prestress level monitoring and defect detection capabilities in concrete-embedded PS tendons. This paper presents a technique based on nonlinear ultrasonic guided waves in the 100 kHz - 2 MHz range for monitoring prestress levels in 7-wire PS tendons. The technique relies on the fact that an axial stress on the tendon generates a proportional radial stress between adjacent wires (interwire stress). In turn, the interwire stress modulates nonlinear effects in ultrasonic wave propagation through both the presence of finite strains and the interwire contact. The nonlinear ultrasonic behavior of the tendon under changing levels of prestress is monitored by tracking higher-order harmonics at (nω) arising under a fundamental guided-wave excitation at (ω). Experimental results will be presented to identify (a) ranges of fundamental excitations at (ω) producing maximum nonlinear response, and (b) optimum lay-out of the transmitting and the receiving transducers within the test tendons. Compared to alternative methods based on linear ultrasonic features, the proposed nonlinear ultrasonic technique appears more sensitive to prestress levels and more robust against changing excitation power at the transmitting transducer or changing transducer/tendon bond conditions.

  18. Experimental diabetes induces structural, inflammatory and vascular changes of Achilles tendons.

    PubMed

    de Oliveira, Rodrigo R; Martins, Conceição S; Rocha, Yuri R; Braga, Allysson B R; Mattos, Rômulo M; Hecht, Fábio; Brito, Gerly A C; Nasciutti, Luiz E

    2013-01-01

    This study aims to demonstrate how the state of chronic hyperglycemia from experimental Diabetes Mellitus can influence the homeostatic imbalance of tendons and, consequently, lead to the characteristics of tendinopathy. Twenty animals were randomly divided into two experimental groups: control group, consisting of healthy rats and diabetic group constituted by rats induced to Diabetes Mellitus I. After twenty-four days of the induction of Diabetes type I, the Achilles tendon were removed for morphological evaluation, cellularity, number and cross-sectional area of blood vessel, immunohistochemistry for Collagen type I, VEGF and NF-κB nuclear localization sequence (NLS) and nitrate and nitrite level. The Achilles tendon thickness (µm/100g) of diabetic animals was significantly increased and, similarly, an increase was observed in the density of fibrocytes and mast cells in the tendons of the diabetic group. The average number of blood vessels per field, in peritendinous tissue, was statistically higher in the diabetic group 3.39 (2.98) vessels/field when compared to the control group 0.89 (1.68) vessels/field p = 0.001 and in the intratendinous region, it was observed that blood vessels were extremely rare in the control group 0.035 (0.18) vessels/field and were often present in the tendons of the diabetic group 0.89 (0.99) vessels/field. The immunohistochemistry analysis identified higher density of type 1 collagen and increased expression of VEGF as well as increased immunostaining for NFκB p50 NLS in the nucleus in Achilles tendon of the diabetic group when compared to the control group. Higher levels of nitrite/nitrate were observed in the experimental group induced to diabetes. We conclude that experimental DM induces notable structural, inflammatory and vascular changes in the Achilles tendon which are compatible with the process of chronic tendinopathy.

  19. Varying whole body vibration amplitude differentially affects tendon and ligament structural and material properties.

    PubMed

    Keller, Benjamin V; Davis, Matthew L; Thompson, William R; Dahners, Laurence E; Weinhold, Paul S

    2013-05-31

    Whole Body Vibration (WBV) is becoming increasingly popular for helping to maintain bone mass and strengthening muscle. Vibration regimens optimized for bone maintenance often operate at hypogravity levels (<1G) and regimens for muscle strengthening often employ hypergravity (>1G) vibrations. The effect of vibratory loads on tendon and ligament properties is unclear though excessive vibrations may be injurious. Our objective was to evaluate how tendon gene expression and the mechanical/histological properties of tendon and ligament were affected in response to WBV in the following groups: no vibration, low vibration (0.3G peak-to-peak), and high vibration (2G peak-to-peak). Rats were vibrated for 20 min a day, 5 days a week, for 5 weeks. Upon sacrifice, the medial collateral ligament (MCL), patellar tendon (PT), and the Achilles Tendon (AT) were isolated with insertion sites intact. All tissues were tensile tested to determine structural and material properties or used for histology. Patellar tendon was also subjected to quantitative RT-PCR to evaluate expression of anabolic and catabolic genes. No differences in biomechanical data between the control and the low vibration groups were found. There was evidence of significant weakness in the MCL with high vibration, but no significant effect on the PT or AT. Histology of the MCL and PT showed a hypercellular tissue response and some fiber disorganization with high vibration. High vibration caused an increase in collagen expression and a trend for an increase in IGF-1 expression suggesting a potential anabolic response to prevent tendon overuse injury.

  20. Health monitoring of prestressing tendons in post-tensioned concrete structures

    NASA Astrophysics Data System (ADS)

    Salamone, Salvatore; Bartoli, Ivan; Nucera, Claudio; Phillips, Robert; Lanza di Scalea, Francesco

    2011-04-01

    Currently 90% of bridges built in California are post-tensioned box-girder. In such structures the steel tendons are the main load-carrying components. The loss of prestress, as well as the presence of defects or the tendon breakage, can be catastrophic for the entire structure. Unfortunately, today there is no well-established method for the monitoring of prestressing (PS) tendons that can provide simultaneous information related to the presence of defects and the level of prestress in a continuous, real time manner. If such a monitoring system were available, considerable savings would be achieved in bridge maintenance since repairs would be implemented in a timely manner without traffic disruptions. This paper presents a health monitoring system for PS tendons in post-tensioned structures of interest to Caltrans. Such a system uses ultrasonic guided waves and embedded sensors to provide simultaneously and in real time, (a) measurements of the level of applied prestress, and (b) defect detection at early grow stages. The proposed PS measurement technique exploits the sensitivity of ultrasonic waves to the inter-wire contact developing in a multi-wire strand as a function of prestress level. In particular the nonlinear ultrasonic behavior of the tendon under changing levels of prestress is monitored by tracking higher-order harmonics at (nω) arising under a fundamental guided-wave excitation at (ω). Moreover this paper also present real-time damage detection and location in post-tensioned bridge joints using Acoustic Emission techniques. Experimental tests on large-scale single-tendon PT joint specimens, subjected to multiple load cycles, will be presented to validate the monitoring of PS loads (through nonlinear ultrasonic probing) and the monitoring of damage progression and location (through acoustic emission techniques). Issues and potential for the use of such techniques to monitor post-tensioned bridges in the field will be discussed.

  1. Structure relates to elastic recoil and functional role in quadriceps tendon and patellar ligament.

    PubMed

    Franchi, Marco; Quaranta, Marilisa; Macciocca, Maria; De Pasquale, Viviana; Ottani, Vittoria; Ruggeri, Alessandro

    2009-04-01

    Tendons and ligaments have similar but slightly different structure and composition. Crimps of tendons and ligaments are morphological structures related to the elastic functional properties of these connective tissues. Aim of this study was to investigate the morphological arrangement of collagen fibres, fibrils and crimping pattern of suprapatellar (rectus femoris tendon-RFT and vastus intermedius tendon-VIT) and infrapatellar connective tissues (patellar ligament-PL) to relate their structural aspects to their common function role of leg extension. RFT, VIT and PL were removed from knees of Sprague-Dawley rats and light and electron microscopy (TEM and SEM) performed. Sagittal sections showed that collagen array and crimping pattern were similar in RFT and PL but differed from VIT. Morphometric analysis confirmed that crimp number was about the same in RFT and PL (5.4+/-1.4 and 6.1+/-2.8 respectively), but it was almost three times higher in VIT (14.5+/-4.7). Similarly crimp top angle in RFT and PL (141.5+/-15.0 degrees and 146.2+/-12.2 degrees respectively) was significantly higher than in VIT (122.3+/-14.8 degrees ) and the crimp base length was more than twice as wide in RFT (75.5+/-22.6microm) and PL (72.3+/-28.9microm) than in VIT (36+/-14.1microm). The smaller, fewer and most crimped crimps in VIT show that this tendon has a greater elastic recoil and responds to higher forces as among quadriceps muscles the vastus intermedius belly contributes the most during knee extension. By contrast, RFT acting as a "stopper" tendon also plays a ligament role by limiting an excessive flexion of the joint during postural rest position of the knee.

  2. Experimental Diabetes Alters the Morphology and Nano-Structure of the Achilles Tendon

    PubMed Central

    de Oliveira, Rodrigo Ribeiro; Medina de Mattos, Rômulo; Magalhães Rebelo, Luciana; Guimarães Meireles Ferreira, Fernanda; Tovar-Moll, Fernanda; Eurico Nasciutti, Luiz; de Castro Brito, Gerly Anne

    2017-01-01

    Although of several studies that associate chronic hyperglycemia with tendinopathy, the connection between morphometric changes as witnessed by magnetic resonance (MR) images, nanostructural changes, and inflammatory markers have not yet been fully established. Therefore, the present study has as a hypothesis that the Achilles tendons of rats with diabetes mellitus (DM) exhibit structural changes. The animals were randomly divided into two experimental groups: Control Group (n = 06) injected with a vehicle (sodium citrate buffer solution) and Diabetic Group (n = 06) consisting of rats submitted to intraperitoneal administration of streptozotocin. MR was performed 24 days after the induction of diabetes and images were used for morphometry using ImageJ software. Morphology of the collagen fibers within tendons was examined using Atomic Force microscopy (AFM). An increase in the dimension of the coronal plane area was observed in the diabetic group (8.583 ± 0.646 mm2/100g) when compared to the control group (4.823 ± 0.267 mm2/100g) resulting in a significant difference (p = 0.003) upon evaluating the Achilles tendons. Similarly, our analysis found an increase in the size of the transverse section area in the diabetic group (1.328 ± 0.103 mm2/100g) in comparison to the control group (0.940 ± 0.01 mm2/100g) p = 0.021. The tendons of the diabetic group showed great irregularity in fiber bundles, including modified grain direction and jagged junctions and deformities in the form of collagen fibrils bulges. Despite the morphological changes observed in the Achilles tendon of diabetic animals, IL1 and TNF-α did not change. Our results suggest that DM promotes changes to the Achilles tendon with important structural modifications as seen by MR and AFM, excluding major inflammatory changes. PMID:28095484

  3. [Connective tissue reinforcing structures of the digital tendon sheaths of the human hand].

    PubMed

    Knott, C; Schmidt, H M

    1986-01-01

    At a greater number of humid preparated human hands, all the ligamentous supports of the digital tendon sheath were exposed and their dimensions were determined. The osteofibrous channels, which contain the long flexor tendons of the digits, were bounded on the one hand by transversely concave shaft areas of the phalanges and the palmar ligaments and on the other side by the fibrous parts of the tendon sheath. From the second to the 5th finger, it has a regular extension of length, which begins proximal at the heads of the metacarpal bones and runs distal to the base of the nail phalanx. In some cases, there is a continuous communication between the digital tendon sheath of the little finger and the carpal synovial sheath. The tendon sheath of the flexor pollicis longus muscle in comparison with it is always in an open communication with the radial synovial sac of the wrist. At the fibrous supports of the digital tendon sheath, one can find constant and inconstant ligamentous structures. Regular shaped ligaments consist of annular fibers (A1 to A5). The proximal complex of fiber supports is a formation of the A1 and A2 ligaments. The band A1 can be divided into 2 ligaments both of roughly equal length, which lay between the head of the metacarpal bone and the base of the proximal phalanx. The strongest fibrous support of the whole digital tendon sheath represents the band A2. It is attached to the midth of the proximal phalanx and increases in strength from proximal to distal. The middle length varies between 6.7 mm at the thumb and 18.7 mm at the middle finger. The distal margin is strengthened by fibrocartilage tissue to be in accordance with the important function as a pulley. The annular band A4 forms the distal supporting complex height above the shaft of the middle phalanx. At the 2nd to the 5th finger it is, with a middle length of 6 to 7 mm, very much shorter than A2 and restrains first of all the tendon of the flexor digitorum profundus muscle. In the area

  4. Musculoskeletal diseases—tendon

    PubMed Central

    Sakabe, Tomoya; Sakai, Takao

    2011-01-01

    Introduction Tendons establish specific connections between muscles and the skeleton by transferring contraction forces from skeletal muscle to bone thereby allowing body movement. Tendon physiology and pathology are heavily dependent on mechanical stimuli. Tendon injuries clinically represent a serious and still unresolved problem since damaged tendon tissues heal very slowly and no surgical treatment can restore a damaged tendon to its normal structural integrity and mechanical strength. Understanding how mechanical stimuli regulate tendon tissue homeostasis and regeneration will improve the treatment of adult tendon injuries that still pose a great challenge in today's medicine. Source of data This review summarizes the current status of tendon treatment and discusses new directions from the point of view of cell-based therapy and regenerative medicine approach. We searched the available literature using PubMed for relevant original articles and reviews. Growing points Identification of tendon cell markers has enabled us to study precisely tendon healing and homeostasis. Clinically, tissue engineering for tendon injuries is an emerging technology comprising elements from the fields of cellular source, scaffold materials, growth factors/cytokines and gene delivering systems. Areas timely for developing research The clinical settings to establish appropriate microenvironment for injured tendons with the combination of these novel cellular- and molecular-based scaffolds will be critical for the treatment. PMID:21729872

  5. Leg tendon glands in male bumblebees ( Bombus terrestris): structure, secretion chemistry, and possible functions

    NASA Astrophysics Data System (ADS)

    Jarau, Stefan; Žáček, Petr; Šobotník, Jan; Vrkoslav, Vladimír; Hadravová, Romana; Coppée, Audrey; Vašíčková, Soňa; Jiroš, Pavel; Valterová, Irena

    2012-12-01

    Among the large number of exocrine glands described in bees, the tarsal glands were thought to be the source of footprint scent marks. However, recent studies showed that the compounds used for marking by stingless bees are secreted by leg tendon instead of tarsal glands. Here, we report on the structure of leg tendon glands in males of Bombus terrestris, together with a description of the chemical composition of their secretions and respective changes of both during the males' lives. The ultrastructure of leg tendon glands shows that the secretory cells are located in three independent regions, separated from each other by unmodified epidermal cells: in the femur, tibia, and basitarsus. Due to the common site of secretion release, the organ is considered a single secretory gland. The secretion of the leg tendon glands of B. terrestris males differs in its composition from those of workers and queens, in particular by (1) having larger proportions of compounds with longer chain lengths, which we identified as wax esters; and (2) by the lack of certain hydrocarbons (especially long chain dienes). Other differences consist in the distribution of double bond positions in the unsaturated hydrocarbons that are predominantly located at position 9 in males but distributed at seven to nine different positions in the female castes. Double bond positions may change chemical and physical properties of a molecule, which can be recognized by the insects and, thus, may serve to convey specific information. The function of male-specific compounds identified from their tendon glands remains elusive, but several possibilities are discussed.

  6. Changes in skeletal muscle and tendon structure and function following genetic inactivation of myostatin in rats

    PubMed Central

    Mendias, Christopher L; Lynch, Evan B; Gumucio, Jonathan P; Flood, Michael D; Rittman, Danielle S; Van Pelt, Douglas W; Roche, Stuart M; Davis, Carol S

    2015-01-01

    Myostatin is a negative regulator of skeletal muscle and tendon mass. Myostatin deficiency has been well studied in mice, but limited data are available on how myostatin regulates the structure and function of muscles and tendons of larger animals. We hypothesized that, in comparison to wild-type (MSTN+/+) rats, rats in which zinc finger nucleases were used to genetically inactivate myostatin (MSTNΔ/Δ) would exhibit an increase in muscle mass and total force production, a reduction in specific force, an accumulation of type II fibres and a decrease and stiffening of connective tissue. Overall, the muscle and tendon phenotype of myostatin-deficient rats was markedly different from that of myostatin-deficient mice, which have impaired contractility and pathological changes to fibres and their extracellular matrix. Extensor digitorum longus and soleus muscles of MSTNΔ/Δ rats demonstrated 20–33% increases in mass, 35–45% increases in fibre number, 20–57% increases in isometric force and no differences in specific force. The insulin-like growth factor-1 pathway was activated to a greater extent in MSTNΔ/Δ muscles, but no substantial differences in atrophy-related genes were observed. Tendons of MSTNΔ/Δ rats had a 20% reduction in peak strain, with no differences in mass, peak stress or stiffness. The general morphology and gene expression patterns were similar between tendons of both genotypes. This large rodent model of myostatin deficiency did not have the negative consequences to muscle fibres and extracellular matrix observed in mouse models, and suggests that the greatest impact of myostatin in the regulation of muscle mass may not be to induce atrophy directly, but rather to block hypertrophy signalling. PMID:25640143

  7. Changes in skeletal muscle and tendon structure and function following genetic inactivation of myostatin in rats.

    PubMed

    Mendias, Christopher L; Lynch, Evan B; Gumucio, Jonathan P; Flood, Michael D; Rittman, Danielle S; Van Pelt, Douglas W; Roche, Stuart M; Davis, Carol S

    2015-04-15

    Myostatin is a negative regulator of skeletal muscle and tendon mass. Myostatin deficiency has been well studied in mice, but limited data are available on how myostatin regulates the structure and function of muscles and tendons of larger animals. We hypothesized that, in comparison to wild-type (MSTN(+/+) ) rats, rats in which zinc finger nucleases were used to genetically inactivate myostatin (MSTN(Δ/Δ) ) would exhibit an increase in muscle mass and total force production, a reduction in specific force, an accumulation of type II fibres and a decrease and stiffening of connective tissue. Overall, the muscle and tendon phenotype of myostatin-deficient rats was markedly different from that of myostatin-deficient mice, which have impaired contractility and pathological changes to fibres and their extracellular matrix. Extensor digitorum longus and soleus muscles of MSTN(Δ/Δ) rats demonstrated 20-33% increases in mass, 35-45% increases in fibre number, 20-57% increases in isometric force and no differences in specific force. The insulin-like growth factor-1 pathway was activated to a greater extent in MSTN(Δ/Δ) muscles, but no substantial differences in atrophy-related genes were observed. Tendons of MSTN(Δ/Δ) rats had a 20% reduction in peak strain, with no differences in mass, peak stress or stiffness. The general morphology and gene expression patterns were similar between tendons of both genotypes. This large rodent model of myostatin deficiency did not have the negative consequences to muscle fibres and extracellular matrix observed in mouse models, and suggests that the greatest impact of myostatin in the regulation of muscle mass may not be to induce atrophy directly, but rather to block hypertrophy signalling.

  8. Fibrillins in Tendon

    PubMed Central

    Giusti, Betti; Pepe, Guglielmina

    2016-01-01

    Tendons among connective tissue, mainly collagen, contain also elastic fibers (EF) made of fibrillin 1, fibrillin 2 and elastin that are broadly distributed in tendons and represent 1–2% of the dried mass of the tendon. Only in the last years, studies on structure and function of EF in tendons have been performed. Aim of this review is to revise data on the organization of EF in tendons, in particular fibrillin structure and function, and on the clinical manifestations associated to alterations of EF in tendons. Indeed, microfibrils may contribute to tendon mechanics; therefore, their alterations may cause joint hypermobility and contractures which have been found to be clinical features in patients with Marfan syndrome (MFS) and Beals syndrome. The two diseases are caused by mutations in genes FBN1 and FBN2 encoding fibrillin 1 and fibrillin 2, respectively. PMID:27812333

  9. Structural and Ultrastructural Characteristics of Bone-Tendon Junction of the Calcaneal Tendon of Adult and Elderly Wistar Rats

    PubMed Central

    Cury, Diego Pulzatto; Dias, Fernando José; Miglino, Maria Angélica; Watanabe, Ii-sei

    2016-01-01

    Tendons are transition tissues that transfer the contractile forces generated by the muscles to the bones, allowing movement. The region where the tendon attaches to the bone is called bone-tendon junction or enthesis and may be classified as fibrous or fibrocartilaginous. This study aims to analyze the collagen fibers and the cells present in the bone-tendon junction using light microscopy and ultrastructural techniques as scanning electron microscopy and transmission electron microscopy. Forty male Wistar rats were used in the experiment, being 20 adult rats at 4 months-old and 20 elderly rats at 20 months-old. The hind limbs of the rats were removed, dissected and prepared to light microscopy, transmission electron microscopy and scanning electron microscopy. The aging process showed changes in the collagen fibrils, with a predominance of type III fibers in the elderly group, in addition to a decrease in the amount of the fibrocartilage cells, fewer and shorter cytoplasmic processes and a decreased synthetic capacity due to degradation of the organelles involved in synthesis. PMID:27078690

  10. Active tendon control of reinforced concrete frame structures subjected to near-fault effects

    NASA Astrophysics Data System (ADS)

    Nigdeli, Sinan Melih; Boduroǧlu, M. Hasan

    2013-10-01

    A reinforced concrete (RC) frame structure was controlled with active tendons under the excitation of near-fault ground motions. Proportional Integral Derivative (PID) type controllers were used and the controller was tuned by using a numerical algorithm. In order to prevent brittle fracture of the structure, the aim of the control is to reduce maximum base shear force. The RC structure was investigated for different characteristic strengths of concrete and the approach is applicable for the structure with 14 MPa concrete strength or higher.

  11. Ultrasound assessment for grading structural tendon changes in supraspinatus tendinopathy: an inter-rater reliability study

    PubMed Central

    Hjarbaek, John; Eshoej, Henrik; Larsen, Camilla Marie; Vobbe, Jette; Juul-Kristensen, Birgit

    2016-01-01

    Aim To evaluate the inter-rater reliability of measuring structural changes in the tendon of patients, clinically diagnosed with supraspinatus tendinopathy (cases) and healthy participants (controls), on ultrasound (US) images captured by standardised procedures. Methods A total of 40 participants (24 patients) were included for assessing inter-rater reliability of measurements of fibrillar disruption, neovascularity, as well as the number and total length of calcifications and tendon thickness. Linear weighted κ, intraclass correlation (ICC), SEM, limits of agreement (LOA) and minimal detectable change (MDC) were used to evaluate reliability. Results ‘Moderate—almost perfect’ κ was found for grading fibrillar disruption, neovascularity and number of calcifications (k 0.60–0.96). For total length of calcifications and tendon thickness, ICC was ‘excellent’ (0.85–0.90), with SEM(Agreement) ranging from 0.63 to 2.94 mm and MDC(group) ranging from 0.28 to 1.29 mm. In general, SEM, LOA and MDC showed larger variation for calcifications than for tendon thickness. Conclusions Inter-rater reliability was moderate to almost perfect when a standardised procedure was applied for measuring structural changes on captured US images and movie sequences of relevance for patients with supraspinatus tendinopathy. Future studies should test intra-rater and inter-rater reliability of the method in vivo for use in clinical practice, in addition to validation against a gold standard, such as MRI. Trial registration number NCT01984203; Pre-results. PMID:27221128

  12. Tendonitis (image)

    MedlinePlus

    ... tendon. It can occur as a result of injury, overuse, or with aging as the tendon loses elasticity. Any action that places prolonged repetitive strain on the forearm muscles can cause tendonitis. The ...

  13. 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

  14. 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

  15. Structural Sizing Methodology for the Tendon-Actuated Lightweight In-Space MANipulator (TALISMAN) System

    NASA Technical Reports Server (NTRS)

    Jones, Thomas C.; Dorsey, John T.; Doggett, William R.

    2015-01-01

    The Tendon-Actuated Lightweight In-Space MANipulator (TALISMAN) is a versatile long-reach robotic manipulator that is currently being tested at NASA Langley Research Center. TALISMAN is designed to be highly mass-efficient and multi-mission capable, with applications including asteroid retrieval and manipulation, in-space servicing, and astronaut and payload positioning. The manipulator uses a modular, periodic, tension-compression design that lends itself well to analytical modeling. Given the versatility of application for TALISMAN, a structural sizing methodology was developed that could rapidly assess mass and configuration sensitivities for any specified operating work space, applied loads and mission requirements. This methodology allows the systematic sizing of the key structural members of TALISMAN, which include the truss arm links, the spreaders and the tension elements. This paper summarizes the detailed analytical derivations and methodology that support the structural sizing approach and provides results from some recent TALISMAN designs developed for current and proposed mission architectures.

  16. Tendon vs. ligament (image)

    MedlinePlus

    ... the eyeball. A tendon serves to move the bone or structure. A ligament is a fibrous connective tissue which attaches bone to bone, and usually serves to hold structures together and keep them stable.

  17. Achilles Tendonitis

    MedlinePlus

    ... You Prevent Achilles Tendonitis? Take these steps to reduce your risk of Achilles tendonitis: Stay in good shape year-round and try to keep your muscles as strong as they can be. Strong, flexible muscles work more efficiently and put less stress on your tendon. Increase the intensity and length ...

  18. Effect of acute resistance exercise and sex on human patellar tendon structural and regulatory mRNA expression.

    PubMed

    Sullivan, Bridget E; Carroll, Chad C; Jemiolo, Bozena; Trappe, Scott W; Magnusson, S Peter; Døssing, Simon; Kjaer, Michael; Trappe, Todd A

    2009-02-01

    Tendon is mainly composed of collagen and an aqueous matrix of proteoglycans that are regulated by enzymes called matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). Although it is known that resistance exercise (RE) and sex influence tendon metabolism and mechanical properties, it is uncertain what structural and regulatory components contribute to these responses. We measured the mRNA expression of tendon's main fibrillar collagens (type I and type III) and the main proteoglycans (decorin, biglycan, fibromodulin, and versican) and the regulatory enzymes MMP-2, MMP-9, MMP-3, and TIMP-1 at rest and after RE. Patellar tendon biopsy samples were taken from six individuals (3 men and 3 women) before and 4 h after a bout of RE and from a another six individuals (3 men and 3 women) before and 24 h after RE. Resting mRNA expression was used for sex comparisons (6 men and 6 women). Collagen type I, collagen type III, and MMP-2 were downregulated (P < 0.05) 4 h after RE but were unchanged (P > 0.05) 24 h after RE. All other genes remained unchanged (P > 0.05) after RE. Women had higher resting mRNA expression (P < 0.05) of collagen type III and a trend (P = 0.08) toward lower resting expression of MMP-3 than men. All other genes were not influenced (P > 0.05) by sex. Acute RE appears to stimulate a change in collagen type I, collagen type III, and MMP-2 gene regulation in the human patellar tendon. Sex influences the structural and regulatory mRNA expression of tendon.

  19. Neuronal regulation of tendon homoeostasis.

    PubMed

    Ackermann, Paul W

    2013-08-01

    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.

  20. 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

  1. Effects of resistance and stretching training programmes on the viscoelastic properties of human tendon structures in vivo

    PubMed Central

    Kubo, Keitaro; Kanehisa, Hiroaki; Fukunaga, Tetsuo

    2002-01-01

    The present study examined whether resistance and stretching training programmes altered the viscoelastic properties of human tendon structures in vivo. Eight subjects completed 8 weeks (4 days per week) of resistance training which consisted of unilateral plantar flexion at 70 % of one repetition maximum with 10 repetitions per set (5 sets per day). They performed resistance training (RT) on one side and resistance training and static stretching training (RST; 10 min per day, 7 days per week) on the other side. Before and after training, the elongation of the tendon structures in the medial gastrocnemius muscle was directly measured using ultrasonography, while the subjects performed ramp isometric plantar flexion up to the voluntary maximum, followed by a ramp relaxation. The relationship between estimated muscle force (Fm) and tendon elongation (L) was fitted to a linear regression, the slope of which was defined as stiffness. The hysteresis was calculated as the ratio of the area within the Fm-L loop to the area beneath the load portion of the curve. The stiffness increased significantly by 18.8 ± 10.4 % for RT and 15.3 ± 9.3 % for RST. There was no significant difference in the relative increase of stiffness between RT and RST. The hysteresis, on the other hand, decreased 17 ± 20 % for RST, but was unchanged for RT. These results suggested that the resistance training increased the stiffness of tendon structures as well as muscle strength and size, and the stretching training affected the viscosity of tendon structures but not the elasticity. PMID:11773330

  2. Application of fiber-reinforced plastic rods as prestressing tendons in concrete structures. Final report

    SciTech Connect

    Mattock, A.H.; Babaei, K.

    1989-08-01

    The study is concerned with the possibility of utilizing fiber-reinforced plastic rods as prestressing tendons, in place of traditional steel tendons, in elements of prestressed-concrete bridges exposed to corrosive environments. A survey was made of available information on the behavior characteristics of fiber-reinforced plastic tension elements and, in particular, those of glass-fiber-reinforced (GFR) tension elements. Also, an analytical study was made of the flexural behavior of concrete elements prestressed by GFR tendons. Based on the analytical study and on the survey of available information, an assessment is made of the impact on the design of prestressed-concrete members if GFR tendons are used. Some preliminary design recommendations are made, together with proposals for research needed before GFR prestressing tendons should be used in practice. Four GFR tendons with Con-Tech Systems anchorages were tested, the primary variable being the embedded length of the GFR rods in the anchorages. All the tendons failed by the rods pulling out of the anchorages. For embedded lengths of 15.2 in or greater, the failure loads were 90% of the advertised tendon strength of 220 ksi, or about 100% of the guaranteed tensile strength of 197 ksi (60 kN/rod).

  3. US imaging in operated tendons.

    PubMed

    Cohen, M

    2012-02-01

    Ultrasound (US) plays an essential role in the follow-up of operated tendons. The US operator must keep in mind three main elements: healing of traumatic injuries of the tendons seems to follow the biological model of histologic healing, surgical repair of a tendon rupture improves the structural parameters of the operated tendon, but it does not grant restitutio ad integrum, and US findings therefore seem poorly correlated with the functional evolution.Before examination, the US operator should be familiar with the nature of the tendon injury that has led to surgery including location, severity, time elapsed between tendon injury and surgical repair, surgical technique, postoperative course and possible complications. US findings in operated as well as non-operated tendons depend on several factors: morphology, structure, vascularization of the tendon, mobility of the tendon and mobility of the peritendinous tissues. Particular features are therefore considered according to the location: shoulder, elbow, wrist, hand, knee, ankle and foot. Interpretation of the US image requires knowledge of the surgical technique and "normal" postoperative appearance of the operated tendon in order to detect pathological findings such as thinning, persistent fluid collections within or around the tendon, persistent hypervascularization, intratendinous calcifications and adhesions.

  4. The role of stretching in tendon injuries.

    PubMed

    Witvrouw, E; Mahieu, N; Roosen, P; McNair, P

    2007-04-01

    The function of tendons can be classified into two categories: tensile force transmission, and storage and release of elastic energy during locomotion. The action of tendons in storing and releasing energy is mainly seen in sports activities with stretch-shortening cycles (SSCs). The more intense the SSC movements are (jumping-like activities), the more frequently tendon problems are observed. High SSC movements impose high loads on tendons. Consequently, tendons that frequently deal with high SSC motion require a high energy-absorbing capacity to store and release this large amount of elastic energy. As the elasticity of tendon structures is a leading factor in the amount of stored energy, prevention and rehabilitation programmes for tendon injuries should focus on increasing this tendon elasticity in athletes performing high SSC movements. Recently, it has been shown that ballistic stretching can significantly increase tendon elasticity. These findings have important clinical implications for treatment and prevention of tendon injuries.

  5. Achilles Tendonitis

    MedlinePlus

    ... up. Tight calf muscles or muscles that lack flexibility decrease a person's range of motion and put an extra strain on the tendon. Running or exercising on a hard or uneven surface or doing lunges or plyometrics without adequate training. A traumatic injury to the Achilles tendon. How ...

  6. Multiscale regression modeling in mouse supraspinatus tendons reveals that dynamic processes act as mediators in structure-function relationships.

    PubMed

    Connizzo, Brianne K; Adams, Sheila M; Adams, Thomas H; Jawad, Abbas F; Birk, David E; Soslowsky, Louis J

    2016-06-14

    Recent advances in technology have allowed for the measurement of dynamic processes (re-alignment, crimp, deformation, sliding), but only a limited number of studies have investigated their relationship with mechanical properties. The overall objective of this study was to investigate the role of composition, structure, and the dynamic response to load in predicting tendon mechanical properties in a multi-level fashion mimicking native hierarchical collagen structure. Multiple linear regression models were investigated to determine the relationships between composition/structure, dynamic processes, and mechanical properties. Mediation was then used to determine if dynamic processes mediated structure-function relationships. Dynamic processes were strong predictors of mechanical properties. These predictions were location-dependent, with the insertion site utilizing all four dynamic responses and the midsubstance responding primarily with fibril deformation and sliding. In addition, dynamic processes were moderately predicted by composition and structure in a regionally-dependent manner. Finally, dynamic processes were partial mediators of the relationship between composition/structure and mechanical function, and results suggested that mediation is likely shared between multiple dynamic processes. In conclusion, the mechanical properties at the midsubstance of the tendon are controlled primarily by fibril structure and this region responds to load via fibril deformation and sliding. Conversely, the mechanical function at the insertion site is controlled by many other important parameters and the region responds to load via all four dynamic mechanisms. Overall, this study presents a strong foundation on which to design future experimental and modeling efforts in order to fully understand the complex structure-function relationships present in tendon.

  7. Tendon repair

    MedlinePlus

    ... is pain-free) Regional anesthesia (the local and surrounding areas are pain-free) General anesthesia (the patient ... used. If needed, tendons are reattached to the surrounding tissue. The surgeon examines the area to see ...

  8. Influence of muscle-tendon unit structure on rate of force development during the squat, countermovement, and drop jumps.

    PubMed

    Earp, Jacob E; Kraemer, William J; Cormie, Prue; Volek, Jeffery S; Maresh, Carl M; Joseph, Michael; Newton, Robert U

    2011-02-01

    Previous research has highlighted the importance of muscle and tendon structure to stretch shortening cycle performance. However, the relationships between muscle and tendon structure to performance are highly dependent on the speed and intensity of the movement. The purpose of this study was to determine if muscle and tendon structure is associated with the rate of force development (RFD) throughout static squat jump (SJ), countermovement jump (CMJ), and drop jump (DJ; 30-cm height). Twenty-five strength- and power-trained men participated in the study. Using ultrasonography, vastus lateralis (VL) and gastrocnemius (GAS) pennation (PEN) and fascicle length (FL), and Achilles tendon (AT) thickness and length were measured. Subjects then performed SJ, CMJ, and DJ, during which RFD was calculated over time 5 distinct time intervals. During CMJs, early RFD could be predicted between 0 and 10 milliseconds by both GAS-FL (r² = 0.213, β = 0.461) and AT-length (r² = 0.191, β = 20.438). Between 10 and 30 milliseconds GAS-FL was a significant predictor of CMJ-RFD (r² = 0.218, β = 0.476). During DJ, initial RFD (0-10 milliseconds) could be significantly predicted by GAS-FL (r² = 0.185, β = 20.434), VL-PEN (r² = 0.189, β = 0.435), and GAS-PEN (r² = 0.188, β = 0.434). These findings suggest that longer ATs may have increased elasticity, which can decrease initial RFD during CMJ; thus, their use in talent identification is not recommended. The GAS fascicle length had an intensity-dependent relationship with RFD, serving to positively predict RFD during early CMJs and an inverse predictor during early DJs. During DDJs, subjects with greater PEN were better able to redirected initial impact forces. Although both strength and plyometric training have been shown to increase FL, only heavy strength training has been shown to increase PEN. Thus, when a high eccentric load or multiple jumps are required, heavy strength training might be used to elicit muscular adaptations

  9. Achilles tendon repair

    MedlinePlus

    Achilles tendon rupture-surgery; Percutaneous Achilles tendon rupture repair ... To fix your torn Achilles tendon, the surgeon will: Make a cut down the back of your heel Make several small cuts rather than one large cut ...

  10. Quadriceps tendon allografts as an alternative to Achilles tendon allografts: a biomechanical comparison.

    PubMed

    Mabe, Isaac; Hunter, Shawn

    2014-12-01

    Quadriceps tendon with a patellar bone block may be a viable alternative to Achilles tendon for anterior cruciate ligament reconstruction (ACL-R) if it is, at a minimum, a biomechanically equivalent graft. The objective of this study was to directly compare the biomechanical properties of quadriceps tendon and Achilles tendon allografts. Quadriceps and Achilles tendon pairs from nine research-consented donors were tested. All specimens were processed to reduce bioburden and terminally sterilized by gamma irradiation. Specimens were subjected to a three phase uniaxial tension test performed in a custom environmental chamber to maintain the specimens at a physiologic temperature (37 ± 2 °C) and misted with a 0.9 % NaCl solution. There were no statistical differences in seven of eight structural and mechanical between the two tendon types. Quadriceps tendons exhibited a significantly higher displacement at maximum load and significantly lower stiffness than Achilles tendons. The results of this study indicated a biomechanical equivalence of aseptically processed, terminally sterilized quadriceps tendon grafts with bone block to Achilles tendon grafts with bone block. The significantly higher displacement at maximum load, and lower stiffness observed for quadriceps tendons may be related to the failure mode. Achilles tendons had a higher bone avulsion rate than quadriceps tendons (86 % compared to 12 %, respectively). This was likely due to observed differences in bone block density between the two tendon types. This research supports the use of quadriceps tendon allografts in lieu of Achilles tendon allografts for ACL-R.

  11. Microstructural stress relaxation mechanics in functionally different tendons.

    PubMed

    Screen, H R C; Toorani, S; Shelton, J C

    2013-01-01

    Tendons experience widely varying loading conditions in vivo. They may be categorised by their function as either positional tendons, which are used for intricate movements and experience lower stress, or as energy storage tendons which act as highly stressed springs during locomotion. Structural and compositional differences between tendons are thought to enable an optimisation of their properties to suit their functional environment. However, little is known about structure-function relationships in tendon. This study adopts porcine flexor and extensor tendon fascicles as examples of high stress and low stress tendons, comparing their mechanical behaviour at the micro-level in order to understand their stress relaxation response. Stress-relaxation was shown to occur predominantly through sliding between collagen fibres. However, in the more highly stressed flexor tendon fascicles, more fibre reorganisation was evident when the tissue was exposed to low strains. By contrast, the low load extensor tendon fascicles appears to have less capacity for fibre reorganisation or shearing than the energy storage tendon, relying more heavily on fibril level relaxation. The extensor fascicles were also unable to sustain loads without rapid and complete stress relaxation. These findings highlight the need to optimise tendon repair solutions for specific tendons, and match tendon properties when using grafts in tendon repairs.

  12. 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

  13. Mathematical models of proprioceptors. II. Structure and function of the Golgi tendon organ.

    PubMed

    Mileusnic, Milana P; Loeb, Gerald E

    2006-10-01

    We developed a physiologically realistic mathematical model of the Golgi tendon organ (GTO) whose elements correspond to anatomical features of the biological receptor. The mechanical interactions of these elements enable it to capture all salient aspects of GTO afferent behavior reported in the literature. The model accurately describes the GTO's static and dynamic responses to activation of single motor units whose muscle fibers insert into the GTO, including the different static and dynamic sensitivities that exist for different types of muscle fibers (S, FR, and FF). Furthermore, it captures the phenomena of self- and cross-adaptation wherein the GTO dynamic response during motor unit activation is reduced by prior activation of the same or a different motor unit, respectively. The model demonstrates various degrees of nonlinear summation of GTO responses resulting from simultaneous activation of multiple motor units. Similarly to the biological GTO, the model suggests that the activation of every additional motor unit to already active motor units that influence the receptor will have a progressively weaker incremental effect on the GTO afferent activity. Finally, the proportional relationship between the cross-adaptation and summation recorded for various pairs of motor units was captured by the model, but only by incorporating a particular type of occlusion between multiple transduction regions that were previously suggested. This occlusion mechanism is consistent with the anatomy of the afferent innervation and its arrangement with respect to the collagen strands inserting into the GTO.

  14. 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.

  15. Bilateral Patellar Tendon Rupture

    DTIC Science & Technology

    2009-07-01

    within the tendon or systemic disorders such as lupus erythematosus , diabetes mellitus, chronic kidney disease, rheumatologic disease, and local or...factors for patellar tendon rupture include obesity, male gender, age 30-40, activities that increase patellar stress, systemic lupus erythematosus ...patellar tendon rupture is a rare occurrence usually associated with chronic degeneration of tendon fibers, use of steroids, or systemic illness. Our

  16. Mesenchymal stem cell applications to tendon healing

    PubMed Central

    Chaudhury, Salma

    2012-01-01

    Summary Tendons are often subject to age related degenerative changes that coincide with a diminished regenerative capacity. Torn tendons often heal by forming scar tissue that is structurally weaker than healthy native tendon tissue, predisposing to mechanical failure. There is increasing interest in providing biological stimuli to increase the tendon reparative response. Stem cells in particular are an exciting and promising prospect as they have the potential to provide appropriate cellular signals to encourage neotendon formation during repair rather than scar tissue. Currently, a number of issues need to be investigated further before it can be determined whether stem cells are an effective and safe therapeutic option for encouraging tendon repair. This review explores the in-vitro and invivo evidence assessing the effect of stem cells on tendon healing, as well as the potential clinical applications. PMID:23738300

  17. Equivalent stiffness after glycosaminoglycan depletion in tendon--an ultra-structural finite element model and corresponding experiments.

    PubMed

    Fessel, Gion; Snedeker, Jess G

    2011-01-07

    The glycosaminoglycan (GAG) side-chains of small leucine-rich proteoglycans have been postulated to mechanically cross-link adjacent collagen fibrils and contribute to tendon mechanics. Enzymatic depletion of tendon GAGs (chondroitin and dermatan sulfate) has emerged as a preferred method to experimentally assess this role. However, GAG removal is typically incomplete and the possibility remains that extant GAGs may remain mechanically functional. The current study specifically investigated the potential mechanical effect of the remaining GAGs after partial enzymatic digestion. A three-dimensional finite element model of tendon was created based upon the concept of proteoglycan mediated inter-fibril load sharing. Approximately 250 interacting, discontinuous collagen fibrils were modeled as having a length of 400 μm, being composed of rod elements of length 67 nm and E-modulus 1 GPa connected in series. Spatial distribution and diameters of these idealized fibrils were derived from a representative cross-sectional electron micrograph of tendon. Rod element lengths corresponded to the collagen fibril D-Period, widely accepted to act as a binding site for decorin and biglycan, the most abundant proteoglycans in tendon. Each element node was connected to nodes of any neighboring fibrils within a radius of 100 nm, the slack length of unstretched chondroitin sulfate. These GAG cross-links were the sole mechanism for lateral load sharing among the discontinuous fibrils, and were modeled as bilinear spring elements. Simulation of tensile testing of tendon with complete cross-linking closely reproduced corresponding experiments on rat tail tendons. Random reduction of 80% of GAG cross-links (matched to a conservative estimate of enzymatic depletion efficacy) predicted a drop of 14% in tendon modulus. Corresponding mechanical properties derived from experiments on rat tail tendons treated in buffer with and without chondroitinase ABC were apparently unaffected, regardless

  18. Comparative analysis of the structure and thermal stability of sea urchin peristome and rat tail tendon collagen.

    PubMed

    Mayne, Janice; Robinson, John J

    2002-01-01

    We have purified collagen from two distinct sources; the vertebrate, rat tail tendon and an invertebrate, sea urchin adult tissue, the peristome. The collagenous nature of the purification products was confirmed by amino acid compositional analysis. Both preparations had high contents of glycine and proline residues and hydroxyproline was also present. The total pyrrolidine (proline+hydroxyproline) content decreased from 17.9 mole% in rat tail collagen to 12.9 mole% in peristome collagen. Distinctly different circular dichroic spectra were measured for these collagens. Analyses of spectra, measured as a function of temperature, revealed distinct thermal denaturation profiles. The melting temperature for rat tail collagen was 38.5 degrees C, while the corresponding value for peristome collagen was significantly lower at 27 degrees C. A similar thermal denaturation profile was obtained for rat tail collagen in digestion experiments using a 41-kDa gelatinase activity, isolated from sea urchin eggs. These results identify structural differences between a typical, vertebrate type I fibrillar collagen and an echinoderm collagen which serves as a constituent of a mutable connective tissue. These differences may relate to the functional roles played by collagen in these distinctly different tissues.

  19. Tendon crimps and peritendinous tissues responding to tensional forces.

    PubMed

    Franchi, M; Quaranta, M; De Pasquale, V; Macciocca, M; Orsini, E; Trirè, A; Ottani, V; Ruggeri, A

    2007-01-01

    Tendons transmit forces generated from muscle to bone making joint movements possible. Tendon collagen has a complex supramolecular structure forming many hierarchical levels of association; its main functional unit is the collagen fibril forming fibers and fascicles. Since tendons are enclosed by loose connective sheaths in continuity with muscle sheaths, it is likely that tendon sheaths could play a role in absorbing/transmitting the forces created by muscle contraction. In this study rat Achilles tendons were passively stretched in vivo to be observed at polarized light microscope (PLM), scanning electron microscope (SEM) and transmission electron microscope (TEM). At PLM tendon collagen fibers in relaxed rat Achilles tendons ran straight and parallel, showing a periodic crimp pattern. Similarly tendon sheaths showed apparent crimps. At higher magnification SEM and TEM revealed that in each tendon crimp large and heterogeneous collagen fibrils running straight and parallel suddenly changed their direction undergoing localized and variable modifications. These fibril modifications were named fibrillar crimps. Tendon sheaths displayed small and uniform fibrils running parallel with a wavy course without any ultrastructural aspects of crimp. Since in passively stretched Achilles tendons fibrillar crimps were still observed, it is likely that during the tendon stretching, and presumably during the tendon elongation in muscle contraction, the fibrillar crimp may be the real structural component of the tendon crimp acting as shock absorber. The peritendinous sheath can be stretched as tendon, but is not actively involved in the mechanism of shock absorber as the fibrillar crimp. The different functional behaviour of tendons and sheaths may be due to the different structural and molecular arrangement of their fibrils.

  20. Diseases of the tendons and tendon sheaths.

    PubMed

    Steiner, Adrian; Anderson, David E; Desrochers, André

    2014-03-01

    Contracted flexor tendon leading to flexural deformity is a common congenital defect in cattle. Arthrogryposis is a congenital syndrome of persistent joint contracture that occurs frequently in Europe as a consequence of Schmallenberg virus infection of the dam. Spastic paresis has a hereditary component, and affected cattle should not be used for breeding purposes. The most common tendon avulsion involves the deep digital flexor tendon. Tendon disruptions may be successfully managed by tenorrhaphy and external coaptation or by external coaptation alone. Medical management alone is unlikely to be effective for purulent tenosynovitis.

  1. Transverse Compression of Tendons.

    PubMed

    Salisbury, S T Samuel; Buckley, C Paul; Zavatsky, Amy B

    2016-04-01

    A study was made of the deformation of tendons when compressed transverse to the fiber-aligned axis. Bovine digital extensor tendons were compression tested between flat rigid plates. The methods included: in situ image-based measurement of tendon cross-sectional shapes, after preconditioning but immediately prior to testing; multiple constant-load creep/recovery tests applied to each tendon at increasing loads; and measurements of the resulting tendon displacements in both transverse directions. In these tests, friction resisted axial stretch of the tendon during compression, giving approximately plane-strain conditions. This, together with the assumption of a form of anisotropic hyperelastic constitutive model proposed previously for tendon, justified modeling the isochronal response of tendon as that of an isotropic, slightly compressible, neo-Hookean solid. Inverse analysis, using finite-element (FE) simulations of the experiments and 10 s isochronal creep displacement data, gave values for Young's modulus and Poisson's ratio of this solid of 0.31 MPa and 0.49, respectively, for an idealized tendon shape and averaged data for all the tendons and E = 0.14 and 0.10 MPa for two specific tendons using their actual measured geometry. The compression load versus displacement curves, as measured and as simulated, showed varying degrees of stiffening with increasing load. This can be attributed mostly to geometrical changes in tendon cross section under load, varying according to the initial 3D shape of the tendon.

  2. The effect of tendon surface treatment on cell attachment for potential enhancement of tendon graft healing: an ex vivo model.

    PubMed

    Hashimoto, Takahiro; Sun, Yu-Long; An, Kai-Nan; Amadio, Peter C; Zhao, Chunfeng

    2012-12-01

    For both tendon allografts and autografts, the surface, initially optimized for gliding, may not be ideal to facilitate tissue integration for graft healing to host tendon or bone. As a prelude to studying tendon-bone integration, we investigated the effect of surface treatments with trypsin or mechanical abrasion on cell attachment to the tendon surface in a canine ex vivo intrasynovial tendon tissue culture model. Intrasynovial tendon allograft surfaces were seeded with cells after the following treatments: (1) no treatment, (2) mechanical abrasion, (3) trypsin, and (4) abrasion and trypsin. The area covered by cells was determined using confocal laser microscopy at one and two weeks. Results were compared to untreated extrasynovial tendon. Additional tendons were characterized with scanning electron microscopy. Tendons with trypsin treatment had significantly more surface coverage with cells than the other groups, after both one and two weeks of culture. In terms of the cellular shape and size, cells on tendons with trypsin treatment spread more and were more polygonal in shape, whereas tendons with mechanical abrasion with/without trypsin treatment contained smaller, more spindle-like cells. Surface roughening can affect cell behavior with topographical stimulation. Trypsin surface digestion exposes a mesh-like structure on the tendon surface, which could enhance cell adherence and, possibly, tendon/bone healing.

  3. Relationships Between Lower-Body Muscle Structure and Lower-Body Strength, Power, and Muscle-Tendon Complex Stiffness.

    PubMed

    Secomb, Josh L; Lundgren, Lina E; Farley, Oliver R L; Tran, Tai T; Nimphius, Sophia; Sheppard, Jeremy M

    2015-08-01

    The purpose of this study was to determine whether any relationships were present between lower-body muscle structure and strength and power qualities. Fifteen elite male surfing athletes performed a battery of lower-body strength and power tests, including countermovement jump (CMJ), squat jump (SJ), isometric midthigh pull (IMTP), and had their lower-body muscle structure assessed with ultrasonography. In addition, lower-body muscle-tendon complex (MTC) stiffness and dynamic strength deficit (DSD) ratio were calculated from the CMJ and IMTP. Significant relationships of large to very large strength were observed between the vastus lateralis (VL) thickness of the left (LVL) and right (RVL) leg and peak force (PF) (r = 0.54-0.77, p < 0.01-0.04), peak velocity (PV) (r = 0.66-0.83, p < 0.01), and peak jump height (r = 0.62-0.80, p < 0.01) in the CMJ and SJ, as well as IMTP PF (r = 0.53-0.60, p = 0.02-0.04). Furthermore, large relationships were found between left lateral gastrocnemius (LG) pennation angle and SJ and IMTP PF (r = 0.53, p = 0.04, and r = 0.70, p < 0.01, respectively) and between LG and IMTP relative PF (r = 0.63, p = 0.01). Additionally, large relationships were identified between lower-body MTC stiffness and DSD ratio (r = 0.68, p < 0.01), right (LG) pennation angle (r = 0.51, p = 0.05), CMJ PF (r = 0.60, p = 0.02), and jump height (r = 0.53, p = 0.04). These results indicate that greater VL thickness and increased LG pennation angle are related to improved performance in the CMJ, SJ, and IMTP. Furthermore, these results suggest that lower-body MTC stiffness explains a large amount of variance in determining an athlete's ability to rapidly apply force during a dynamic movement.

  4. Biologics for tendon repair☆

    PubMed Central

    Docheva, Denitsa; Müller, Sebastian A.; Majewski, Martin; Evans, Christopher H.

    2015-01-01

    Tendon injuries are common and present a clinical challenge to orthopedic surgery mainly because these injuries often respond poorly to treatment and require prolonged rehabilitation. Therapeutic options used to repair ruptured tendons have consisted of suture, autografts, allografts, and synthetic prostheses. To date, none of these alternatives has provided a successful long-term solution, and often the restored tendons do not recover their complete strength and functionality. Unfortunately, our understanding of tendon biology lags far behind that of other musculoskeletal tissues, thus impeding the development of new treatment options for tendon conditions. Hence, in this review, after introducing the clinical significance of tendon diseases and the present understanding of tendon biology, we describe and critically assess the current strategies for enhancing tendon repair by biological means. These consist mainly of applying growth factors, stem cells, natural biomaterials and genes, alone or in combination, to the site of tendon damage. A deeper understanding of how tendon tissue and cells operate, combined with practical applications of modern molecular and cellular tools could provide the long awaited breakthrough in designing effective tendon-specific therapeutics and overall improvement of tendon disease management. PMID:25446135

  5. The Role of Detraining in Tendon Mechanobiology

    PubMed Central

    Frizziero, Antonio; Salamanna, Francesca; Della Bella, Elena; Vittadini, Filippo; Gasparre, Giuseppe; Nicoli Aldini, Nicolò; Masiero, Stefano; Fini, Milena

    2016-01-01

    Introduction: Several conditions such as training, aging, estrogen deficiency and drugs could affect the biological and anatomo-physiological characteristics of the tendon. Additionally, recent preclinical and clinical studies examined the effect of detraining on tendon, showing alterations in its structure and morphology and in tenocyte mechanobiology. However, few data evaluated the importance that cessation of training might have on tendon. Basically, we do not fully understand how tendons react to a phase of training followed by sudden detraining. Therefore, within this review, we summarize the studies where tendon detraining was examined. Materials and Methods: A descriptive systematic literature review was carried out by searching three databases (PubMed, Scopus and Web of Knowledge) on tendon detraining. Original articles in English from 2000 to 2015 were included. In addition, the search was extended to the reference lists of the selected articles. A public reference manager (www.mendeley.com) was adopted to remove duplicate articles. Results: An initial literature search yielded 134 references (www.pubmed.org: 53; www.scopus.com: 11; www.webofknowledge.com: 70). Fifteen publications were extracted based on the title for further analysis by two independent reviewers. Abstracts and complete articles were after that reviewed to evaluate if they met inclusion criteria. Conclusions: The revised literature comprised four clinical studies and an in vitro and three in vivo reports. Overall, the results showed that tendon structure and properties after detraining are compromised, with an alteration in the tissue structural organization and mechanical properties. Clinical studies usually showed a lesser extent of tendon alterations, probably because preclinical studies permit an in-depth evaluation of tendon modifications, which is hard to perform in human subjects. In conclusion, after a period of sudden detraining (e.g., after an injury), physical activity should

  6. p38 MAPK Signaling in Postnatal Tendon Growth and Remodeling

    PubMed Central

    Schwartz, Andrew J.; Sarver, Dylan C.; Sugg, Kristoffer B.; Dzierzawski, Justin T.; Gumucio, Jonathan P.; Mendias, Christopher L.

    2015-01-01

    Tendon is a dynamic tissue whose structure and function is influenced by mechanical loading, but little is known about the fundamental mechanisms that regulate tendon growth and remodeling in vivo. Data from cultured tendon fibroblasts indicated that the p38 MAPK pathway plays an important role in tendon fibroblast proliferation and collagen synthesis in vitro. To gain greater insight into the mechanisms of tendon growth, and explore the role of p38 MAPK signaling in this process, we tested the hypotheses that inducing plantaris tendon growth through the ablation of the synergist Achilles tendon would result in rapid expansion of a neotendon matrix surrounding the original tendon, and that treatment with the p38 MAPK inhibitor SB203580 would prevent this growth. Rats were treated with vehicle or SB203580, and subjected to synergist ablation by bilateral tenectomy of the Achilles tendon. Changes in histological and biochemical properties of plantaris tendons were analyzed 3, 7, or 28 days after overload, and comparisons were made to non-overloaded animals. By 28 days after overload, tendon mass had increased by 30% compared to non-overloaded samples, and cross-sectional area (CSA) increased by around 50%, with most of the change occurring in the neotendon. The expansion in CSA initially occurred through the synthesis of a hyaluronic acid rich matrix that was progressively replaced with mature collagen. Pericytes were present in areas of active tendon growth, but never in the original tendon ECM. Inhibition of p38 MAPK resulted in a profound decrease in IL6 expression, and had a modest effect on the expression of other ECM and cell proliferation genes, but had a negligible impact on overall tendon growth. The combined results from this study provided novel insights into tendon mechanobiology, and suggest that p38 MAPK signaling does not appear to be necessary for tendon growth in vivo. PMID:25768932

  7. 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

  8. SAFE modeling of waves for the structural health monitoring of prestressing tendons

    NASA Astrophysics Data System (ADS)

    Bartoli, Ivan; Marzani, Alessandro; Lanza di Scalea, Francesco; Rizzo, Piervincenzo; Viola, Erasmo; Sorrivi, Elisa; Phillips, Robert

    2007-04-01

    This paper reports on the status of ongoing collaborative studies between UCSD, University of Bologna and University of Pittsburgh aimed at developing a monitoring system for prestressing strands in post-tensioned structures based on guided ultrasonic waves (GUWs) and built-in sensors. A Semi-Analytical Finite Element (SAFE) method was first used to compute dispersion curves of a pretwisted waveguide representing a seven-wire strand. The strand embedded in grout and surrounded by a concrete media was subsequently modeled as an axisymmetric waveguide. The SAFE method allows to account for the material damping and can be used to discriminate low loss guided modes. Experimental tests targeted at the defect detection and prestress level monitoring were performed. Notch like defects, machined in a seven wire strand, were successfully detected using a reflection-based Damage Index (D.I.) vector. The D.I. vector was extracted from GUWs measurements which were processed using Discrete Wavelet Transform (DWT). A four dimensional Outlier analysis was performed to discriminate indications of flaws. In a parallel study, transmission measurements were collected to identify wave features sensitive to prestress level in strands embedded in post-tensioned concrete blocks. The most sensitive features are being investigated further to assess their reliability in a monitoring system whit sensors embedded in a real post-tensioned concrete structure.

  9. Structure and dynamics of water in tendon from NMR relaxation measurements.

    PubMed Central

    Peto, S; Gillis, P; Henri, V P

    1990-01-01

    Nuclear magnetic relaxation times were measured in collagen tissue when varying the orientation of the fiber with respect to the static field. T1 was found to be only slightly dependent on theta, the fiber-to-field angle, but T2 was very sensitive to the orientation, with a maximum value at the magic angle. The transverse decay curves were multiexponential. Their deconvolution displayed four components; the ones that decayed most slowly were almost independent of theta, but the two fastest ones showed a strong angular dependence that was interpreted with a cross-relaxation model. Quadrupolar dips were visible in the 1/T1 dispersion curves. These dips were independent of theta, so that the magnetization transfer could also be assumed to be independent of the fiber orientation. Finally, each component was assigned to a fraction of protons localized in the macromolecular structure and characterized by particular dynamics. The model of Woessner was applied to the water molecules tightly bound into the macromolecules, which resulted in a dynamical description of this water fraction. This description is compatible with the two-sites model of Ramachandran based on x-ray diffraction and with the extensive studies of Berendsen. However, the important indications obtained from the deconvolution lead to a less static representation of the tissue. PMID:2297563

  10. Characterization via atomic force microscopy of discrete plasticity in collagen fibrils from mechanically overloaded tendons: Nano-scale structural changes mimic rope failure.

    PubMed

    Baldwin, Samuel J; Kreplak, Laurent; Lee, J Michael

    2016-07-01

    Tendons exposed to tensile overload show a structural alteration at the fibril scale termed discrete plasticity. Serial kinks appear along individual collagen fibrils that are susceptible to enzymatic digestion and are thermally unstable. Using atomic force microscopy we mapped the topography and mechanical properties in dehydrated and hydrated states of 25 control fibrils and 25 fibrils displaying periodic kinks, extracted from overloaded bovine tail tendons. Using the measured modulus of the hydrated fibrils as a probe of molecular density, we observed a non-linear negative correlation between molecular density and kink density of individual fibrils. This is accompanied by an increase in water uptake with kink density and a doubling of the coefficient of variation of the modulus between kinked, and control fibrils. The mechanical property maps of kinked collagen fibrils show radial heterogeneity that can be modeled as a high-density core surrounded by a low-density shell. The core of the fibril contains the kink structures characteristic of discrete plasticity; separated by inter-kink regions, which often retain the D-banding structure. We propose that the shell and kink structures mimic characteristic damage motifs observed in laid rope strands.

  11. Mechanical properties of human patellar tendon at the hierarchical levels of tendon and fibril.

    PubMed

    Svensson, René B; Hansen, Philip; Hassenkam, Tue; Haraldsson, Bjarki T; Aagaard, Per; Kovanen, Vuokko; Krogsgaard, Michael; Kjaer, Michael; Magnusson, S Peter

    2012-02-01

    Tendons are strong hierarchical structures, but how tensile forces are transmitted between different levels remains incompletely understood. Collagen fibrils are thought to be primary determinants of whole tendon properties, and therefore we hypothesized that the whole human patellar tendon and its distinct collagen fibrils would display similar mechanical properties. Human patellar tendons (n = 5) were mechanically tested in vivo by ultrasonography. Biopsies were obtained from each tendon, and individual collagen fibrils were dissected and tested mechanically by atomic force microscopy. The Young's modulus was 2.0 ± 0.5 GPa, and the toe region reached 3.3 ± 1.9% strain in whole patellar tendons. Based on dry cross-sectional area, the Young's modulus of isolated collagen fibrils was 2.8 ± 0.3 GPa, and the toe region reached 0.86 ± 0.08% strain. The measured fibril modulus was insufficient to account for the modulus of the tendon in vivo when fibril content in the tendon was accounted for. Thus, our original hypothesis was not supported, although the in vitro fibril modulus corresponded well with reported in vitro tendon values. This correspondence together with the fibril modulus not being greater than that of tendon supports that fibrillar rather than interfibrillar properties govern the subfailure tendon response, making the fibrillar level a meaningful target of intervention. The lower modulus found in vitro suggests a possible adverse effect of removing the tissue from its natural environment. In addition to the primary work comparing the two hierarchical levels, we also verified the existence of viscoelastic behavior in isolated human collagen fibrils.

  12. Effect of glenohumeral abduction angle on the mechanical interaction between the supraspinatus and infraspinatus tendons for the intact, partial-thickness torn, and repaired supraspinatus tendon conditions.

    PubMed

    Andarawis-Puri, Nelly; Kuntz, Andrew F; Ramsey, Matthew L; Soslowsky, Louis J

    2010-07-01

    Rotator cuff tears are difficult to manage because of the structural and mechanical inhomogeneity of the supraspinatus tendon. Previously, we showed that with the arm at the side, the supraspinatus and infraspinatus tendons mechanically interact such that conditions that increase supraspinatus tendon strain, such as load or full-thickness tears, also increase infraspinatus tendon strain. This suggests that the infraspinatus tendon may shield the supraspinatus tendon from further injury while becoming at increased risk of injury itself. In this study, the effect of glenohumeral abduction angle on the interaction between the two tendons was evaluated for supraspinatus tendon partial-thickness tears and two repair techniques. Principal strains were quantified in both tendons for 0 degrees , 30 degrees , and 60 degrees of glenohumeral abduction. Results showed that interaction between the two tendons is interrupted by an increase in abduction angle for all supraspinatus tendon conditions evaluated. Infraspinatus tendon strain was lower at 30 degrees and 60 degrees than at 0 degrees abduction angle. In conclusion, interaction between the supraspinatus and infraspinatus tendons is interrupted with increase in abduction angle. Additionally, 30 degrees abduction should be further evaluated for management of rotator cuff tears and repairs as it is the angle at which both supraspinatus and infraspinatus tendon strain is decreased.

  13. 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.

  14. Crimp morphology in relaxed and stretched rat Achilles tendon.

    PubMed

    Franchi, Marco; Fini, Milena; Quaranta, Marilisa; De Pasquale, Viviana; Raspanti, Mario; Giavaresi, Gianluca; Ottani, Vittoria; Ruggeri, Alessandro

    2007-01-01

    Fibrous extracellular matrix of tendon is considered to be an inextensible anatomical structure consisting of type I collagen fibrils arranged in parallel bundles. Under polarized light microscopy the collagen fibre bundles appear crimped with alternating dark and light transverse bands. This study describes the ultrastructure of the collagen fibrils in crimps of both relaxed and in vivo stretched rat Achilles tendon. Under polarized light microscopy crimps of relaxed Achilles tendons appear as isosceles or scalene triangles of different size. Tendon crimps observed via SEM and TEM show the single collagen fibrils that suddenly change their direction containing knots. The fibrils appear partially squeezed in the knots, bent on the same plane like bayonets, or twisted and bent. Moreover some of them lose their D-period, revealing their microfibrillar component. These particular aspects of collagen fibrils inside each tendon crimp have been termed 'fibrillar crimps' and may fulfil the same functional role. When tendon is physiologically stretched in vivo the tendon crimps decrease in number (46.7%) (P<0.01) and appear more flattened with an increase in the crimp top angle (165 degrees in stretched tendons vs. 148 degrees in relaxed tendons, P<0.005). Under SEM and TEM, the 'fibrillar crimps' are still present, never losing their structural identity in straightened collagen fibril bundles of stretched tendons even where tendon crimps are not detectable. These data suggest that the 'fibrillar crimp' may be the true structural component of the tendon crimp acting as a shock absorber during physiological stretching of Achilles tendon.

  15. Distal Biceps Tendon Rupture

    DTIC Science & Technology

    2010-06-01

    distal tendon. Although these findings overlap with those seen in tendinopathy , the presence of bone marrow edema at the radial tuberosity and fluid in...the bicipitoradial bursa suggests a partial tear rather than tendinopathy .3 When the distal biceps tendon tear is complete, MR imaging shows

  16. Forefoot tendon transfers.

    PubMed

    Veljkovic, Andrea; Lansang, Edward; Lau, Johnny

    2014-03-01

    Flexible forefoot deformities, such as hallux varus, clawed hallux, hammer toes, and angular lesser toe deformities, can be treated effectively with tendon transfers. Based on the presentation of the flexible forefoot deformities, tendon transfers can be used as the primary treatment or as adjuncts to bony procedures when there are components of fixed deformities.

  17. The tibialis posterior tendon.

    PubMed

    Lhoste-Trouilloud, A

    2012-02-01

    The tibialis posterior tendon is the largest and anteriormost tendon in the medial ankle. It produces plantar flexion and supination of the ankle and stabilizes the plantar vault. Sonographic assessment of this tendon is done with high-frequency, linear-array transducers; an optimal examination requires transverse retromalleolar, longitudinal retromalleolar, and distal longitudinal scans, as well as dynamic studies. Disorders of the posterior tibial tendon include chronic tendinopathy with progressive rupture, tenosynovitis, acute rupture, dislocation and instability, enthesopathies. The most common lesion is a progressive "chewing gum" lesion that develops in a setting of chronic tendinopathy; it is usually seen in overweight women over 50 years of age with valgus flat feet. Medial ankle pain must also be carefully investigated, and the presence of instability assessed with dynamic maneuvers (forced inversion, or dorsiflexion) of the foot. Sonography plays an important role in the investigation of disorders involving the posterior tibial tendon.

  18. Tendon gradient mineralization for tendon to bone interface integration.

    PubMed

    Qu, Jin; Thoreson, Andrew R; Chen, Qingshan; An, Kai-Nan; Amadio, Peter C; Zhao, Chunfeng

    2013-11-01

    Tendon-to-bone integration is a great challenge for tendon or ligament reconstruction regardless of use of autograft or allograft tendons. We mineralized the tendon, thus transforming the tendon-to-bone into a "bone-to-bone" interface for healing. Sixty dog flexor digitorum profundus (FDP) tendons were divided randomly into five groups: (1) normal FDP tendon, (2) CaP (non-extraction and mineralization without fetuin), (3) CaPEXT (Extraction by Na2 HPO4 and mineralization without fetuin), (4) CaPFetuin (non-extraction and mineralization with fetuin), and (5) CaPEXTFetuin (extraction and mineralization with fetuin). The calcium and phosphate content significantly increased in tendons treated with combination of extraction and fetuin compared to the other treatments. Histology also revealed a dense mineral deposition throughout the tendon outer layers and penetrated into the tendon to a depth of 200 µm in a graded manner. Compressive moduli were significantly lower in the four mineralized groups compared with normal control group. No significant differences in maximum failure strength or stiffness were found in the suture pull-out test among all groups. Mineralization of tendon alters the interface from tendon to bone into mineralized tendon to bone, which may facilitate tendon-to-bone junction healing following tendon or ligament reconstruction.

  19. Musculoskeletal integration at the wrist underlies the modular development of limb tendons

    PubMed Central

    Huang, Alice H.; Riordan, Timothy J.; Pryce, Brian; Weibel, Jennifer L.; Watson, Spencer S.; Long, Fanxin; Lefebvre, Veronique; Harfe, Brian D.; Stadler, H. Scott; Akiyama, Haruhiko; Tufa, Sara F.; Keene, Douglas R.; Schweitzer, Ronen

    2015-01-01

    The long tendons of the limb extend from muscles that reside in the zeugopod (arm/leg) to their skeletal insertions in the autopod (paw). How these connections are established along the length of the limb remains unknown. Here, we show that mouse limb tendons are formed in modular units that combine to form a functional contiguous structure; in muscle-less limbs, tendons develop in the autopod but do not extend into the zeugopod, and in the absence of limb cartilage the zeugopod segments of tendons develop despite the absence of tendons in the autopod. Analyses of cell lineage and proliferation indicate that distinct mechanisms govern the growth of autopod and zeugopod tendon segments. To elucidate the integration of these autopod and zeugopod developmental programs, we re-examined early tendon development. At E12.5, muscles extend across the full length of a very short zeugopod and connect through short anlagen of tendon progenitors at the presumptive wrist to their respective autopod tendon segment, thereby initiating musculoskeletal integration. Zeugopod tendon segments are subsequently generated by proximal elongation of the wrist tendon anlagen, in parallel with skeletal growth, underscoring the dependence of zeugopod tendon development on muscles for tendon anchoring. Moreover, a subset of extensor tendons initially form as fused structures due to initial attachment of their respective wrist tendon anlage to multiple muscles. Subsequent individuation of these tendons depends on muscle activity. These results establish an integrated model for limb tendon development that provides a framework for future analyses of tendon and musculoskeletal phenotypes. PMID:26062940

  20. Musculoskeletal integration at the wrist underlies the modular development of limb tendons.

    PubMed

    Huang, Alice H; Riordan, Timothy J; Pryce, Brian; Weibel, Jennifer L; Watson, Spencer S; Long, Fanxin; Lefebvre, Veronique; Harfe, Brian D; Stadler, H Scott; Akiyama, Haruhiko; Tufa, Sara F; Keene, Douglas R; Schweitzer, Ronen

    2015-07-15

    The long tendons of the limb extend from muscles that reside in the zeugopod (arm/leg) to their skeletal insertions in the autopod (paw). How these connections are established along the length of the limb remains unknown. Here, we show that mouse limb tendons are formed in modular units that combine to form a functional contiguous structure; in muscle-less limbs, tendons develop in the autopod but do not extend into the zeugopod, and in the absence of limb cartilage the zeugopod segments of tendons develop despite the absence of tendons in the autopod. Analyses of cell lineage and proliferation indicate that distinct mechanisms govern the growth of autopod and zeugopod tendon segments. To elucidate the integration of these autopod and zeugopod developmental programs, we re-examined early tendon development. At E12.5, muscles extend across the full length of a very short zeugopod and connect through short anlagen of tendon progenitors at the presumptive wrist to their respective autopod tendon segment, thereby initiating musculoskeletal integration. Zeugopod tendon segments are subsequently generated by proximal elongation of the wrist tendon anlagen, in parallel with skeletal growth, underscoring the dependence of zeugopod tendon development on muscles for tendon anchoring. Moreover, a subset of extensor tendons initially form as fused structures due to initial attachment of their respective wrist tendon anlage to multiple muscles. Subsequent individuation of these tendons depends on muscle activity. These results establish an integrated model for limb tendon development that provides a framework for future analyses of tendon and musculoskeletal phenotypes.

  1. 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.

  2. Laminar Tendon Composites with Enhanced Mechanical Properties

    PubMed Central

    Alberti, Kyle A.; Sun, Jeong-Yun; Illeperuma, Widusha R.; Suo, Zhigang; Xu, Qiaobing

    2015-01-01

    Purpose A strong isotropic material that is both biocompatible and biodegradable is desired for many biomedical applications, including rotator cuff repair, tendon and ligament repair, vascular grafting, among others. Recently, we developed a technique, called “bioskiving” to create novel 2D and 3D constructs from decellularized tendon, using a combination of mechanical sectioning, and layered stacking and rolling. The unidirectionally aligned collagen nanofibers (derived from sections of decellularized tendon) offer good mechanical properties to the constructs compared with those fabricated from reconstituted collagen. Methods In this paper, we studied the effect that several variables have on the mechanical properties of structures fabricated from tendon slices, including crosslinking density and the orientation in which the fibers are stacked. Results We observed that following stacking and crosslinking, the strength of the constructs is significantly improved, with crosslinked sections having an ultimate tens ile strength over 20 times greater than non-crosslinked samples, and a modulus nearly 50 times higher. The mechanism of the mechanical failure mode of the tendon constructs with or without crosslinking was also investigated. Conclusions The strength and fiber organization, combined with the ability to introduce transversely isotropic mechanical properties makes the laminar tendon composites a biocompatiable material that may find future use in a number of biomedical and tissue engineering applications. PMID:25691802

  3. Mechanical characteristics of native tendon slices for tissue engineering scaffold

    PubMed Central

    Qin, Ting-Wu; Chen, Qingshan; Sun, Yu-Long; Steinmann, Scott P.; Amadio, Peter C.; An, Kai-Nan; Zhao, Chunfeng

    2014-01-01

    The purpose of this study was to characterize the mechanical behavior of tendon slices with different thicknesses. Tendon slices of 100, 200, 300, 400, and 500 μm thickness were mechanically tested. The 300 μm slices were further tested for strength and modulus after 21,000-cycle fatigue testing under different applied strain levels (0, 1, 3, 5, 8, 10, and 12%). The tendon slice structure, morphology, and viability of bone marrow stromal cells (BMSCs) seeded onto the slices were also examined with histology, scanning electron microscopy, and vital cell labeling, respectively. Tendon slices 300 μm or more in thickness had similar ultimate tensile strength and Young's modulus to the intact tendon bundle. A strain of 5% or less did not cause any structural damage, nor did it change the mechanical properties of a 300 μm-thick tendon slice after 21,000-cycle fatigue testing. BMSCs were viable between and on the tendon slices after 2 weeks in tissue culture. This study demonstrated that, if tendon slices are used as a scaffold for tendon tissue engineering, slices 300 μm or more in thickness would be preferable from a mechanical strength point of view. If mechanical stimulation is performed for seeded-cell preparations, 5% strain or less would be appropriate. PMID:22323314

  4. 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

  5. Inflamed shoulder tendons (image)

    MedlinePlus

    Tearing and inflammation of the tendons of the shoulder muscles can occur in sports which require the ... pitching, swimming, and lifting weights. Most often the shoulder will heal if a break is taken from ...

  6. Proximal Biceps Tendonitis

    MedlinePlus

    ... teens, biceps tendonitis is usually an overuse injury. Baseball pitchers, swimmers, tennis players, and people who have ... But if you swim or play tennis or baseball, that might not be an option! If your ...

  7. Tendon synovial cells secrete fibronectin in vivo and in vitro

    SciTech Connect

    Banes, A.J.; Link, G.W.; Bevin, A.G.; Peterson, H.D.; Gillespie, Y.; Bynum, D.; Watts, S.; Dahners, L.

    1988-01-01

    The chemistry and cell biology of the tendon have been largely overlooked due to the emphasis on collagen, the principle structural component of the tendon. The tendon must not only transmit the force of muscle contraction to bone to effect movement, but it must also glide simultaneously over extratendonous tissues. Fibronectin is classified as a cell attachment molecule that induces cell spreading and adhesion to substratum. The external surface of intact avian flexor tendon stained positively with antibody to cellular fibronectin. However, if the surface synovial cells were first removed with collagenase, no positive reaction with antifibronectin antibody was detected. Analysis of immunologically stained frozen sections of tendon also revealed fibronectin at the tendon synovium, but little was associated with cells internal in tendon. The staining pattern with isolated, cultured synovial cells and fibroblasts from the tendon interior substantiated the histological observations. Analysis of polyacrylamide gel profiles of /sup 35/S-methionine-labeled proteins synthesized by synovial cells and internal fibroblasts indicated that fibronectin was synthesized principally by synovial cells. Fibronectin at the tendon surface may play a role in cell attachment to prevent cell removal by the friction of gliding. Alternatively, fibronectin, with its binding sites for hyaluronic acid and collagen, may act as a complex for boundary lubrication.

  8. Specialisation of extracellular matrix for function in tendons and ligaments.

    PubMed

    Birch, Helen L; Thorpe, Chavaunne T; Rumian, Adam P

    2013-01-01

    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.

  9. Modelling approaches for evaluating multiscale tendon mechanics

    PubMed Central

    Fang, Fei; Lake, Spencer P.

    2016-01-01

    Tendon exhibits anisotropic, inhomogeneous and viscoelastic mechanical properties that are determined by its complicated hierarchical structure and varying amounts/organization of different tissue constituents. Although extensive research has been conducted to use modelling approaches to interpret tendon structure–function relationships in combination with experimental data, many issues remain unclear (i.e. the role of minor components such as decorin, aggrecan and elastin), and the integration of mechanical analysis across different length scales has not been well applied to explore stress or strain transfer from macro- to microscale. This review outlines mathematical and computational models that have been used to understand tendon mechanics at different scales of the hierarchical organization. Model representations at the molecular, fibril and tissue levels are discussed, including formulations that follow phenomenological and microstructural approaches (which include evaluations of crimp, helical structure and the interaction between collagen fibrils and proteoglycans). Multiscale modelling approaches incorporating tendon features are suggested to be an advantageous methodology to understand further the physiological mechanical response of tendon and corresponding adaptation of properties owing to unique in vivo loading environments. PMID:26855747

  10. Tendon transfer or tendon graft for ruptured finger extensor tendons in rheumatoid hands.

    PubMed

    Chung, U S; Kim, J H; Seo, W S; Lee, K H

    2010-05-01

    We evaluated the clinical outcome of tendon reconstruction using tendon graft or tendon transfer and the parameters related to clinical outcome in 51 wrists of 46 patients with rheumatoid arthritis with finger extensor tendon ruptures. At a mean follow-up of 5.6 years, the mean metacarpophalangeal (MP) joint extension lag was 8 degrees (range, 0-45) and the mean visual analogue satisfaction scale was 74 (range, 10-100). Clinical outcome did not differ significantly between tendon grafting and tendon transfer. The MP joint extension lag correlated with the patient's satisfaction score, but the pulp-to-palm distance did not correlate with patient satisfaction. We conclude that both tendon grafting and tendon transfer are reliable reconstruction methods for ruptured finger extensor tendons in rheumatoid hands.

  11. Regulation of tendon differentiation by scleraxis distinguishes force-transmitting tendons from muscle-anchoring tendons.

    PubMed

    Murchison, Nicholas D; Price, Brian A; Conner, David A; Keene, Douglas R; Olson, Eric N; Tabin, Clifford J; Schweitzer, Ronen

    2007-07-01

    The scleraxis (Scx) gene, encoding a bHLH transcription factor, is expressed in the progenitors and cells of all tendon tissues. To determine Scx function, we produced a mutant null allele. Scx-/- mice were viable, but showed severe tendon defects, which manifested in a drastically limited use of all paws and back muscles and a complete inability to move the tail. Interestingly, although the differentiation of all force-transmitting and intermuscular tendons was disrupted, other categories of tendons, the function of which is mainly to anchor muscles to the skeleton, were less affected and remained functional, enabling the viability of Scx-/- mutants. The force-transmitting tendons of the limbs and tail varied in the severity to which they were affected, ranging from dramatic failure of progenitor differentiation resulting in the loss of segments or complete tendons, to the formation of small and poorly organized tendons. Tendon progenitors appeared normal in Scx-/- embryos and a phenotype resulting from a failure in the condensation of tendon progenitors to give rise to distinct tendons was first detected at embryonic day (E)13.5. In the tendons that persisted in Scx-/- mutants, we found a reduced and less organized tendon matrix and disorganization at the cellular level that led to intermixing of tenocytes and endotenon cells. The phenotype of Scx-/- mutants emphasizes the diversity of tendon tissues and represents the first molecular insight into the important process of tendon differentiation.

  12. Biodegradable synthetic scaffolds for tendon regeneration

    PubMed Central

    Reverchon, Ernesto; Baldino, Lucia; Cardea, Stefano; De Marco, Iolanda

    2012-01-01

    Summary Tissue regeneration is aimed at producing biological or synthetic scaffolds to be implanted in the body for regenerate functional tissues. Several techniques and materials have been used to obtain biodegradable synthetic scaffolds, on which adhesion, growth, migration and differentiation of human cells has been attempted. Scaffolds for tendon regeneration have been less frequently proposed, because they have a complex hierarchical structure and it is very difficult to mimic their peculiar mechanical properties. In this review, we critically analyzed the proposed materials and fabrication techniques for tendon tissue engineering and we indicated new preparation processes, based on the use of supercritical fluids, to produce scaffolds with characteristics very similar to the native tendon structure. PMID:23738295

  13. Complete Achilles tendon ruptures.

    PubMed

    Landvater, S J; Renström, P A

    1992-10-01

    Achilles tendon ruptures can be treated nonsurgically in the nonathletic or low-end recreational athletic patient, particularly those more than 50 years of age, provided the treating physician does not delay in the diagnosis and treatment (preferably less than 48 hrs and possibly less than 1 week). The patient should be advised of the higher incidence of re-rupture of the tendon when treated nonsurgically. Surgical treatment is recommended for patients who are young and athletic. This is particularly true because the major criticism of surgical treatment has been the complication rate, which has decreased to a low level and to a mild degree, usually not significantly affecting the repair over time. Surgical treatment in these individuals seems to be superior not only in regard to re-rupture but also in assuring the correct apposition of the tendon ends and in placing the necessary tension on the tendon to secure appropriate orientation of the collagen fibers. This in turn allows them to regain full strength, power, endurance, and an early return to sports. Surgery is also recommended for late diagnosed ruptures where there is significant lengthening of the tendon. Surgical technique should involve a medial incision to avoid the sural nerve, absorbable suture, and augmentation with fascia or tendon where there is a gap or late rupture. Postoperatively, the immobilization should be 7 to 10 days in a splint. A walking boot with early motion in plantar flexion or a short leg cast with the tendon under slight tension should thereafter be used for 4 to 5 weeks. An early and well-supervised rehabilitation program should be initiated to restore the patient to the preinjury activity level.

  14. Effect of muscle contraction levels on the force-length relationship of the human Achilles tendon during lengthening of the triceps surae muscle-tendon unit.

    PubMed

    Sugisaki, Norihide; Kawakami, Yasuo; Kanehisa, Hiroaki; Fukunaga, Tetsuo

    2011-07-28

    Findings from animal experiments are sometimes contradictory to the idea that the tendon structure is a simple elastic spring in series with muscle fibers, and suggest influence of muscle contraction on the tendon mechanical properties. The purpose of the present study was to investigate the influence of muscle contraction levels on the force-length relationship of the human Achilles tendon during lengthening of the triceps surae muscle-tendon unit. For seven subjects, ankle dorsiflexion was performed without (passive condition) and with contraction of plantar flexor muscles (eccentric conditions, at 3 contraction levels) on an isokinetic dynamometer. Deformation of the Achilles tendon during each trial was measured using ultrasonography. The Achilles tendon force corresponding to the tendon elongation of 10mm in the passive condition was significantly smaller than those in the eccentric conditions (p<0.05 or p<0.01). Within the eccentric conditions, the Achilles tendon force corresponding to the tendon elongation of 10mm was significantly greater in the maximal contraction level than those in submaximal eccentric conditions (p<0.05 or p<0.01). In addition, the tendon stiffness was greater in higher contraction levels (p<0.05 or p<0.01). Present results suggest that the human tendon structure is not a simple elastic spring in series with muscle fibers.

  15. Steroid injections - tendon, bursa, joint

    MedlinePlus

    ... ency/article/007678.htm Steroid injections - tendon, bursa, joint To use the sharing features on this page, ... often painful. It can be injected into a joint, tendon, or bursa. Description Your health care provider ...

  16. 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); Permenter, Frank Noble (Inventor); Mehling, Joshua S. (Inventor)

    2013-01-01

    A humanoid robot includes a robotic hand having at least one finger. An actuation system for the robotic finger includes an actuator assembly which is supported by the robot and is spaced apart from the finger. A tendon extends from the actuator assembly to the at least one finger and ends in a tendon terminator. The actuator assembly is operable to actuate the tendon to move the tendon terminator and, thus, the finger.

  17. The biceps tendons: From the top and from the bottom

    PubMed Central

    Brasseur, J.L.

    2011-01-01

    The biceps brachii muscle, which inserts proximally onto the scapula and distally onto the forearm, has several tendons with numerous anatomic peculiarities, which render their sonographic examination highly variable. Proximally, the tendon of the short head of the biceps inserts onto the coracoid process and that of the long head on the superior aspect of the glenoid. The distal biceps tendon is bifurcated, and it generally inserts on the radial tuberosity, around which it rolls during pronation/supination. There is a third distal structure, the Lacertus fibrosus, an aponeurosis that branches off from the medial aspect of the tendon, crossing the median artery and median nerve, and inserting on the superficial aponeurosis of the flexor muscles. The sonographic examination of these tendons focuses on nine separate zones of interest: the glenoid insertion of the long head, its extension to the upper pole of the humeral head, the rotator interval, the reflection to the upper bicipital groove, the bicipital groove, the upper myotendinous junction, the lower myotendinous junction, the distal tendon(s), and the inferior enthesis. Because of their morphological and topographical characteristics, the biceps tendons are subject to a variety of lesions, some of which are frequently misdiagnosed on the basis of clinical findings. Ultrasound plays an important role in detecting and characterizing these lesions. Proper examination of the biceps (the distal portion in particular) is a difficult task that cannot be improvised. PMID:23397031

  18. Relationship between tendon stiffness and failure: a metaanalysis.

    PubMed

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

    2013-07-01

    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 (R(2) = 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.

  19. 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

  20. Age-related differences in Achilles tendon properties and triceps surae muscle architecture in vivo.

    PubMed

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

    2012-11-01

    This study examined the concurrent age-related differences in muscle and tendon structure and properties. Achilles tendon morphology and mechanical properties and triceps surae muscle architecture were measured from 100 subjects [33 young (24 ± 2 yr) and 67 old (75 ± 3 yr)]. Motion analysis-assisted ultrasonography was used to determine tendon stiffness, Young's modulus, and hysteresis during isometric ramp contractions. Ultrasonography was used to measure muscle architectural features and size and tendon cross-sectional area. Older participants had 17% lower (P < 0.01) Achilles tendon stiffness and 32% lower (P < 0.001) Young's modulus than young participants. Tendon cross-sectional area was also 16% larger (P < 0.001) in older participants. Triceps surae muscle size was smaller (P < 0.05) and gastrocnemius medialis muscle fascicle length shorter (P < 0.05) in old compared with young. Maximal plantarflexion force was associated with tendon stiffness and Young's modulus (r = 0.580, P < 0.001 and r = 0.561, P < 0.001, respectively). Comparison between old and young subjects with similar strengths did not reveal a difference in tendon stiffness. The results suggest that regardless of age, Achilles tendon mechanical properties adapt to match the level of muscle performance. Old people may compensate for lower tendon material properties by increasing tendon cross-sectional area. Lower tendon stiffness in older subjects might be beneficial for movement economy in low-intensity locomotion and thus optimized for their daily activities.

  1. Two cases of chronic knee pain caused by unusual injuries to the popliteus tendon.

    PubMed

    Davalos, Eric A; Barank, David; Varma, Rajeev K

    2016-01-01

    Injuries to the popliteus tendon are less frequent than injuries to the menisci or ligamentous structures of the knee. When they do occur, injuries to the popliteus tendon tend to be the result of trauma and associated with injuries to other components of the knee. The most commonly seen injuries include tears at the musculotendinous junction and avulsion tears at the lateral femoral condyle insertion site. This report presents two unusual injuries of the popliteus tendon in patients with chronic knee pain: an isolated split tear of the tendon and a subluxed tendon residing within the lateral joint space.

  2. Two cases of chronic knee pain caused by unusual injuries to the popliteus tendon

    PubMed Central

    DAVALOS, ERIC A.; BARANK, DAVID; VARMA, RAJEEV K.

    2016-01-01

    Injuries to the popliteus tendon are less frequent than injuries to the menisci or ligamentous structures of the knee. When they do occur, injuries to the popliteus tendon tend to be the result of trauma and associated with injuries to other components of the knee. The most commonly seen injuries include tears at the musculotendinous junction and avulsion tears at the lateral femoral condyle insertion site. This report presents two unusual injuries of the popliteus tendon in patients with chronic knee pain: an isolated split tear of the tendon and a subluxed tendon residing within the lateral joint space. PMID:27386449

  3. 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.

  4. Ten weeks of treadmill running decreases stiffness and increases collagen turnover in tendons of old mice.

    PubMed

    Wood, Lauren K; Brooks, Susan V

    2016-02-01

    Increased tendon stiffness in response to mechanical loading is well established in young animals. Given that tendons stiffen with aging, we aimed to determine the effect of increased loading on tendons of old animals. We subjected 28-month-old mice to 10 weeks of uphill treadmill running; sedentary 8- and 28-month-old mice served as controls. Following training, plantaris tendon stiffness and modulus were reduced by approximately half, such that the values were not different from those of tendons from adult sedentary animals. The decrease in plantaris tendon stiffness was accompanied by a similar reduction in the levels of advanced glycation end-product protein adducts in tibialis anterior tendons of trained compared with sedentary old mice. In Achilles tendons, elevated mRNA levels for collagen type 1, matrix-metalloproteinase-8, and lysyl oxidase following training suggest that collagen turnover was likely also increased. The dramatic mechanical and structural changes induced by training occurred independent of changes in cell density or tendon morphology. Finally, Achilles tendon calcification was significantly reduced following exercise. These results demonstrate that, in response to exercise, tendons from old animals are capable of replacing damaged and dysfunctional components of extracellular matrix with tissue that is mechanically and structurally comparable to adult tissue.

  5. Tenocyte contraction induces crimp formation in tendon-like tissue

    PubMed Central

    Holmes, David F.; Hill, Patrick; Kadler, Karl E.; Margetts, Lee

    2013-01-01

    Tendons are composed of longitudinally aligned collagen fibrils arranged in bundles with an undulating pattern, called crimp. The crimp structure is established during embryonic development and plays a vital role in the mechanical behaviour of tendon, acting as a shock absorber during loading. However, the mechanism of crimp formation is unknown, partly because of the difficulties of studying tendon development in vivo. Here we used a 3D cell culture system in which embryonic tendon fibroblasts synthesize a tendon-like construct comprised of collagen fibrils arranged in parallel bundles. Investigations using polarized light microscopy, scanning electron microscopy and fluorescence microscopy showed that tendon-constructs contained a regular pattern of wavy collagen fibrils. Tensile testing indicated that this superstructure was a form of embryonic crimp producing a characteristic toe region in the stress-strain curves. Furthermore, contraction of tendon fibroblasts was the critical factor in the buckling of collagen fibrils during the formation of the crimp structure. Using these biological data, a finite element model was built that mimics the contraction of the tendon fibroblasts and monitors the response of the ECM. The results show that the contraction of the fibroblasts is a sufficient mechanical impulse to build a planar wavy pattern. Furthermore, the value of crimp wavelength was determined by the mechanical properties of the collagen fibrils and inter-fibrillar matrix. Increasing fibril stiffness combined with constant matrix stiffness led to an increase in crimp wavelength. The data suggest a novel mechanism of crimp formation, and the finite element model indicates the minimum requirements to generate a crimp structure in embryonic tendon. PMID:21735243

  6. Tenocyte contraction induces crimp formation in tendon-like tissue.

    PubMed

    Herchenhan, Andreas; Kalson, Nicholas S; Holmes, David F; Hill, Patrick; Kadler, Karl E; Margetts, Lee

    2012-03-01

    Tendons are composed of longitudinally aligned collagen fibrils arranged in bundles with an undulating pattern, called crimp. The crimp structure is established during embryonic development and plays a vital role in the mechanical behaviour of tendon, acting as a shock-absorber during loading. However, the mechanism of crimp formation is unknown, partly because of the difficulties of studying tendon development in vivo. Here, we used a 3D cell culture system in which embryonic tendon fibroblasts synthesise a tendon-like construct comprised of collagen fibrils arranged in parallel bundles. Investigations using polarised light microscopy, scanning electron microscopy and fluorescence microscopy showed that tendon constructs contained a regular pattern of wavy collagen fibrils. Tensile testing indicated that this superstructure was a form of embryonic crimp producing a characteristic toe region in the stress-strain curves. Furthermore, contraction of tendon fibroblasts was the critical factor in the buckling of collagen fibrils during the formation of the crimp structure. Using these biological data, a finite element model was built that mimics the contraction of the tendon fibroblasts and monitors the response of the Extracellular matrix. The results show that the contraction of the fibroblasts is a sufficient mechanical impulse to build a planar wavy pattern. Furthermore, the value of crimp wavelength was determined by the mechanical properties of the collagen fibrils and inter-fibrillar matrix. Increasing fibril stiffness combined with constant matrix stiffness led to an increase in crimp wavelength. The data suggest a novel mechanism of crimp formation, and the finite element model indicates the minimum requirements to generate a crimp structure in embryonic tendon.

  7. 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

  8. Tendon to bone healing and its implications for surgery

    PubMed Central

    Bunker, Daniel Lee John; Ilie, Victor; Ilie, Vladimir; Nicklin, Sean

    2014-01-01

    Summary Entheses are complex structures which act to reduce stress concentrations between tendon and skeleton tissues. Understanding the development and function of the enthesis organ has implications for surgical repair, particularly in regards to healing and the regulation of tendon to bone engraftment. In this paper we review the development and function of entheses as well as the enthesis organ concept. Next we examine the process of tendon to bone healing and how this can be regulated, before addressing implications for surgical repair and post-operative care. PMID:25489553

  9. Alterations of tendons in diabetes mellitus: what are the current findings?

    PubMed

    Shi, Liu; Rui, Yun-Feng; Li, Gang; Wang, Chen

    2015-08-01

    As a connective tissue, tendon connects the muscle and bone, and plays the key role in the locomotor system. Some previous studies have shown the pathological alternations in diabetic tendons, which might result in the structural and functional changes, and even accelerate the process of diabetic foot. In this review, we examined the current findings of the diabetic tendons in the form of various aspects, and summarized the clinical presentation, imaging, biomechanical, histopathological, cellular and molecular abnormalities in the diabetic tendons. The progress of diabetic tendon damage is complicated and the main hypotheses include the excessive accumulation of AGEs, the altered inflammatory response, neovascularization and insensitive neuropathy. However, the cellular and molecular mechanisms of these alterations are still ambiguous. Tendon stem/progenitor cells (TSPCs) have been discovered to play important roles in both tendon physiology and tendon pathology. Recently, we identified TSPCs from patellar tendons in our well-established diabetic rat model and found impaired tenogenic differentiation potential of these cells. We proposed a new hypothesis that the impaired cell functions of diabetic TSPCs might be the underlying cellular and molecular mechanism of the diabetic tendon alternations. These findings should be helpful to establish a better therapeutic strategy for diabetic tendon repair and regeneration.

  10. Spontaneous Iliopsoas Tendon Tear

    PubMed Central

    Rodriguez, Mary; Patnaik, Soumya; Wang, Peter

    2016-01-01

    Hip pain is one of the most common reasons for the elderly to present to the emergency department, and the differential diagnosis spectrum is vast. Iliopsoas injury is a relatively uncommon condition that may present with hip or groin pain. It is usually seen in athletes due to trauma, particularly flexion injuries. However, spontaneous iliopsoas tendon tear is extremely rare, and only a small number of cases have been reported; it has an estimated prevalence of 0.66% in individuals from 7 to 95 years. Risk factors include aging, use of steroids, and chronic diseases. Magnetic resonance imaging (MRI) using its high soft-tissue contrast resolution remains the most valuable imaging modality. A prompt diagnosis and treatment, which is usually conservative, is important to improve the quality of life in this group of patients. We describe a case of spontaneous iliopsoas tendon tear in an elderly woman. PMID:26929854

  11. 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

  12. Tendon degeneration and chronic shoulder pain: changes in the collagen composition of the human rotator cuff tendons in rotator cuff tendinitis.

    PubMed Central

    Riley, G P; Harrall, R L; Constant, C R; Chard, M D; Cawston, T E; Hazleman, B L

    1994-01-01

    . These changes may be the result of repeated minor injury and microscopic fibre damage or a consequence of local factors such as reduced vascular perfusion, tissue hypoxia, altered mechanical forces and the influence of cytokines. These collagenous changes may accumulate with age and substantially weaken the tendon structure, predisposing the tendon to rotator cuff tendinitis and eventual tendon rupture. Images PMID:8037494

  13. The acoustoelastic effect in prestressing tendons

    NASA Astrophysics Data System (ADS)

    Washer, Glenn Alden

    There are currently more than 130,000 prestressed concrete bridges in the United States and approximately 37,000 of these bridges are more than 30 years old. Steel tendons that are pre-tensioned to counteract the effect of design loads are critical to structural performance of these bridges. However, there are currently no accepted nondestructive evaluation techniques to evaluate the condition of these tendons. The goal of this research was to examine ultrasonic stress measurement techniques for the condition assessment of prestressing tendons. Acoustoelastic measurements were made in prestressing rods and strands, and constants are reported that relate the change in ultrasonic velocity to the change in stress. The effects of dispersion in prestressing tendons, which act as circular wave guides for ultrasonic waves, are evaluated. Factors that could effect the design of a practical sensor are examined, including temperature dependence, effect of varying boundary conditions, and the variation in acoustoelastic properties between typical materials produced by different manufacturers. It is concluded that several of these factors have a larger effect on the ultrasonic velocities than stress. Therefore, it may be impractical to design a sensor system to measure absolute stress, but measurement of stress changes from a known initial condition may be possible under certain circumstances.

  14. Mouse models in tendon and ligament research.

    PubMed

    Mienaltowski, Michael J; Birk, David E

    2014-01-01

    Mutant mouse models are valuable resources for the study of tendon and ligament biology. Many mutant mouse models are used because their manifested phenotypes mimic clinical pathobiology for several heritable disorders, such as Ehlers-Danlos Syndrome and Osteogenesis Imperfecta. Moreover, these models are helpful for discerning roles of specific genes in the development, maturation, and repair of musculoskeletal tissues. There are several categories of genes with essential roles in the synthesis and maintenance of tendon and ligament structures. The form and function of these tissues depend highly upon fibril-forming collagens, the primary extracellular macromolecules of tendons and ligaments. Models for these fibril-forming collagens, as well as for regulatory molecules like FACITs and SLRPs, are important for studying fibril assembly, growth, and maturation. Additionally, mouse models for growth factors and transcription factors are useful for defining regulation of cell proliferation, cell differentiation, and cues that stimulate matrix synthesis. Models for membrane-bound proteins assess the roles of cell-cell communication and cell-matrix interaction. In some cases, special considerations need to be given to spatio-temporal control of a gene in a model. Thus, conditional and inducible mouse models allow for specific regulation of genes of interest. Advances in mouse models have provided valuable tools for gaining insight into the form and function of tendons and ligaments.

  15. Conflicts, snapping and instability of the tendons. Pictorial essay

    PubMed Central

    Fantino, Olivier; Borne, J.; Bordet, Bertrand

    2012-01-01

    Conflicts, snapping and instability of the tendons are common, and ultrasound (US) is the method of choice for evidencing these conditions thanks to the possibility to perform dynamic maneuvers during imaging studies. A conflict can occur between a tendon and a bone structure, other tendons, the retinacula or pulleys. Snapping can occur due to instability caused by rupture of the retinaculum, conflict between a thickened retinaculum and a bone prominence or due to an abnormal position of the tendon. Instability can occur due to insufficient ability of the retinaculum to keep the tendons in the bone groove or its failure to hold the tendons applied to the bone. The technique for evidencing conflicts, snapping and instability of the tendons is very demanding because it requires a thorough knowledge of the US appearance and dynamic maneuvers. However, at the present time US examination completed with dynamic maneuvers is the investigation of choice for evidencing these disorders and providing the clinicians with the necessary information. PMID:23396604

  16. Conflicts, snapping and instability of the tendons. Pictorial essay.

    PubMed

    Fantino, Olivier; Borne, J; Bordet, Bertrand

    2012-02-01

    Conflicts, snapping and instability of the tendons are common, and ultrasound (US) is the method of choice for evidencing these conditions thanks to the possibility to perform dynamic maneuvers during imaging studies. A conflict can occur between a tendon and a bone structure, other tendons, the retinacula or pulleys. Snapping can occur due to instability caused by rupture of the retinaculum, conflict between a thickened retinaculum and a bone prominence or due to an abnormal position of the tendon. Instability can occur due to insufficient ability of the retinaculum to keep the tendons in the bone groove or its failure to hold the tendons applied to the bone.The technique for evidencing conflicts, snapping and instability of the tendons is very demanding because it requires a thorough knowledge of the US appearance and dynamic maneuvers. However, at the present time US examination completed with dynamic maneuvers is the investigation of choice for evidencing these disorders and providing the clinicians with the necessary information.

  17. Tendon-driven manipulators: Analysis, synthesis, and control

    NASA Astrophysics Data System (ADS)

    Lee, Jyh-Jone

    As the development of light-weight, small volume, and versatile manipulators has grown in the field of robotics, the need for more efficient and relevant power transmission systems in the manipulators has become increasingly apparent. It is clear that the advent of efficient, low friction, and backlash-free actuation systems promises to provide significant gains in manipulator performance. Tendon transmission has been widely used to actuate small volume and light-weight articulated manipulators, such as dextrous mechanical hands, for it permits actuators to be installed remotely from the end-effector, thus reducing the bulk and inertia of the manipulator system. Current research on such actuation systems is accomplished on the basis of specialized designs. The lack of systematic approaches has limited our scope in realizing performance of such transmission systems. Therefore, when associated with systematic methodologies, the study of tendon-driven manipulators promises to be of major importance in the field of robotics. This dissertation is concerned with four issues to enhance our use and understanding of tendon-driven manipulators. First, a systematic approach for the kinematics analysis of tendon-driven manipulators is established. A graph is used to represent the kinematic structure of tendon-driven manipulators. It is shown that the kinematic structure of tendon-driven manipulators is in every way similar to that of epicyclic gear trains. The fundamental circuit equation developed for the kinematic analysis of epicyclic gear trains can thus be applied to this type of mechanism. The displacement equation governing joint angle space and tendon space can easily be obtained. Secondly, the concept of structural isomorphism and the structural characteristics of tendon-driven manipulators are investigated. Based on the explored properties, a methodology for the enumeration of tendon-driven manipulators is developed. By applying the methodology, a class of kinematic

  18. Achilles tendon injuries in athletes.

    PubMed

    Kvist, M

    1994-09-01

    Two-thirds of Achilles tendon injuries in competitive athletes are paratenonitis and one-fifth are insertional complaints (bursitis and insertion tendinitis). The remaining afflictions consist of pain syndromes of the myotendineal junction and tendinopathies. The majority of Achilles tendon injuries from sport occur in males, mainly because of their higher rates of participation in sport, but also with tendinopathies a gender difference is probably indicated. Athletes in running sports have a high incidence of Achilles tendon overuse injuries. About 75% of total and the majority of partial tendon ruptures are related to sports activities usually involving abrupt repetitive jumping and sprinting movements. Mechanical factors and a sedentary lifestyle play a role in the pathology of these injuries. Achilles tendon overuse injuries occur at a higher rate in older athletes than most other typical overuse injuries. Recreational athletes with a complete Achilles tendon rupture are about 15 years younger than those with other spontaneous tendon ruptures. Following surgery, about 70 to 90% of athletes have a successful comeback after Achilles tendon injury. Surgery is required in about 25% of athletes with Achilles tendon overuse injuries and the frequency of surgery increases with patient age and duration of symptoms as well as occurrence of tendinopathic changes. However, about 20% of injured athletes require a re-operation for Achilles tendon overuse injuries, and about 3 to 5% are compelled to abandon their sports career because of these injuries. Myotendineal junction pain should be treated conservatively. Partial Achilles tendon ruptures are primarily treated conservatively, although the best treatment method of chronic partial rupture seems to be surgery. Complete Achilles tendon ruptures of athletes are treated surgically, because this increases the likelihood of athletes reaching preinjury activity levels and minimises the risk of re-ruptures. Marked forefoot

  19. Mineral Distributions at the Developing Tendon Enthesis

    PubMed Central

    Schwartz, Andrea G.; Pasteris, Jill D.; Genin, Guy M.; Daulton, Tyrone L.; Thomopoulos, Stavros

    2012-01-01

    Tendon attaches to bone across a functionally graded interface, “the enthesis”. A gradient of mineral content is believed to play an important role for dissipation of stress concentrations at mature fibrocartilaginous interfaces. Surgical repair of injured tendon to bone often fails, suggesting that the enthesis does not regenerate in a healing setting. Understanding the development and the micro/nano-meter structure of this unique interface may provide novel insights for the improvement of repair strategies. This study monitored the development of transitional tissue at the murine supraspinatus tendon enthesis, which begins postnatally and is completed by postnatal day 28. The micrometer-scale distribution of mineral across the developing enthesis was studied by X-ray micro-computed tomography and Raman microprobe spectroscopy. Analyzed regions were identified and further studied by histomorphometry. The nanometer-scale distribution of mineral and collagen fibrils at the developing interface was studied using transmission electron microscopy (TEM). A zone (∼20 µm) exhibiting a gradient in mineral relative to collagen was detected at the leading edge of the hard-soft tissue interface as early as postnatal day 7. Nanocharacterization by TEM suggested that this mineral gradient arose from intrinsic surface roughness on the scale of tens of nanometers at the mineralized front. Microcomputed tomography measurements indicated increases in bone mineral density with time. Raman spectroscopy measurements revealed that the mineral-to-collagen ratio on the mineralized side of the interface was constant throughout postnatal development. An increase in the carbonate concentration of the apatite mineral phase over time suggested possible matrix remodeling during postnatal development. Comparison of Raman-based observations of localized mineral content with histomorphological features indicated that development of the graded mineralized interface is linked to endochondral

  20. Mineral distributions at the developing tendon enthesis.

    PubMed

    Schwartz, Andrea G; Pasteris, Jill D; Genin, Guy M; Daulton, Tyrone L; Thomopoulos, Stavros

    2012-01-01

    Tendon attaches to bone across a functionally graded interface, "the enthesis". A gradient of mineral content is believed to play an important role for dissipation of stress concentrations at mature fibrocartilaginous interfaces. Surgical repair of injured tendon to bone often fails, suggesting that the enthesis does not regenerate in a healing setting. Understanding the development and the micro/nano-meter structure of this unique interface may provide novel insights for the improvement of repair strategies. This study monitored the development of transitional tissue at the murine supraspinatus tendon enthesis, which begins postnatally and is completed by postnatal day 28. The micrometer-scale distribution of mineral across the developing enthesis was studied by X-ray micro-computed tomography and Raman microprobe spectroscopy. Analyzed regions were identified and further studied by histomorphometry. The nanometer-scale distribution of mineral and collagen fibrils at the developing interface was studied using transmission electron microscopy (TEM). A zone (∼20 µm) exhibiting a gradient in mineral relative to collagen was detected at the leading edge of the hard-soft tissue interface as early as postnatal day 7. Nanocharacterization by TEM suggested that this mineral gradient arose from intrinsic surface roughness on the scale of tens of nanometers at the mineralized front. Microcomputed tomography measurements indicated increases in bone mineral density with time. Raman spectroscopy measurements revealed that the mineral-to-collagen ratio on the mineralized side of the interface was constant throughout postnatal development. An increase in the carbonate concentration of the apatite mineral phase over time suggested possible matrix remodeling during postnatal development. Comparison of Raman-based observations of localized mineral content with histomorphological features indicated that development of the graded mineralized interface is linked to endochondral

  1. [Tendon ruptures of the shoulder].

    PubMed

    Habermeyer, P

    1989-08-01

    Common sports, involving raising the arms above the head, i.e., throwing, racquet games and swimming, often result in rotator cuff tendinitis. During the throwing motion, the humeral head and its overlying biceps tendon and rotator cuff must pass rapidly under the coraco-acromial arch. Damage to these structures can occur by several mechanism. First, an increase in the size of the structures passing underneath the arch may lead to impingement. This can occur either by way of hypertrophy of the musculotendinous cuff or by way of inflammation of the cuff. Second, a decreased space available underneath the arch secondary to osteophyte formation of the acromion and fibrosis of the subacromial space may lead to impingement. Third, weakness or incompetence of the rotator cuff allows the humerus to ride up and impinge on the coracoacromial arch with motion of the shoulder. Tendinitis can be combined with increased laxity of the glenohumeral joint and/or acquired instability due to a labral tear. Prevention of overuse injuries is a cornerstone of our treatment concept. The muscle tendon unit requires passive and neuromuscular facilitated streching after warming-up exercises. Muscular imbalance and weakness are prevented by balanced eccentric strenthening with particular attention to the external rotators and scapular muscles. Knowledge of the mechanics of the pitching motion, tennis serve, swimming stroke, etc. is of paramount importance in the prevention of injuries. As the onset of shoulder problems contributes to a particularly fatiguing situation, extreme fatique performance severity should be avoided. Every effort must be made to apply conservative treatment when overuse problems arise in the athlete's shoulder.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Cyclic tensile strain upregulates collagen synthesis in isolated tendon fascicles

    SciTech Connect

    Screen, Hazel R.C. . E-mail: H.R.C.Screen@qmul.ac.uk; Shelton, Julia C.; Bader, Dan L.; Lee, David A.

    2005-10-21

    Mechanical stimulation has been implicated as an important regulatory factor in tendon homeostasis. In this study, a custom-designed tensile loading system was used to apply controlled mechanical stimulation to isolated tendon fascicles, in order to examine the effects of 5% cyclic tensile strain at 1 Hz on cell proliferation and matrix synthesis. Sample viability and gross structural composition were maintained over a 24 h loading period. Data demonstrated no statistically significant differences in cell proliferation or glycosaminoglycan production, however, collagen synthesis was upregulated with the application of cyclic tensile strain over the 24 h period. Moreover, a greater proportion of the newly synthesised matrix was retained within the sample after loading. These data provide evidence of altered anabolic activity within tendon in response to mechanical stimuli, and suggest the importance of cyclic tensile loading for the maintenance of the collagen hierarchy within tendon.

  3. Cellular therapy in bone-tendon interface regeneration

    PubMed Central

    Rothrauff, Benjamin B; Tuan, Rocky S

    2014-01-01

    The intrasynovial bone-tendon interface is a gradual transition from soft tissue to bone, with two intervening zones of uncalcified and calcified fibrocartilage. Following injury, the native anatomy is not restored, resulting in inferior mechanical properties and an increased risk of re-injury. Recent in vivo studies provide evidence of improved healing when surgical repair of the bone-tendon interface is augmented with cells capable of undergoing chondrogenesis. In particular, cellular therapy in bone-tendon healing can promote fibrocartilage formation and associated improvements in mechanical properties. Despite these promising results in animal models, cellular therapy in human patients remains largely unexplored. This review highlights the development and structure-function relationship of normal bone-tendon insertions. The natural healing response to injury is discussed, with subsequent review of recent research on cellular approaches for improved healing. Finally, opportunities for translating in vivo findings into clinical practice are identified. PMID:24326955

  4. Parameters influencing prevalence and outcome of tendonitis in Thoroughbred and Arabian racehorses.

    PubMed

    Kalisiak, O

    2012-01-01

    Flexor tendonitis and suspensory desmitis are among most prevalent musculoskeletal injuries observed in racehorses. The aim of this study was to determine which horse and race-related parameters can help to diminish the possibility of injury or--when injury has occurred--to evaluate the potential for the horse to continue a successful career after convalescence. Special attention was given to the comparison of Arabian and Thoroughbred racehorses. 187 horses with ultrasonographically visible lesions were included in the study. Following parameters were analyzed: structure (Superficial Digital Flexor Tendon [SDFT], Deep Digital Flexor Tendon [DDFT], Suspensory Ligament [SL]); percentage of cross sectional area increase; hypoechogenic lesion character; in horses with SDF tendonitis - tendonitis grade according to Genovese. This study showed that Thoroughbreds are more at risk of musculoskeletal problems than Arabian racehorses. In both breeds, the most frequent injuries concern SDFT, then SL. Over 95% of tendonitis concern forelimbs. In Thoroughbreds, the prevalence of tendonitis is higher in bigger horses, in males when compared to females and in fence/steeple racehorses when compared to flat track racehorses. The inside limb is more at risk of SDF tendonitis, when the external limb - of SL desmitis. Tendonitis severity increases with age and is greater in steeplechasers when compared to flat track racehorses. The outcome of tendonitis without hypoechogenic lesion is much better than that with hypoechogenic lesion. Evaluation of hypoechogenic lesion length is an easy and accurate prognosis tool, as the chances of returning to racing drop dramatically with lesions longer than 12 cm.

  5. The effect of lubricin on the gliding resistance of mouse intrasynovial tendon.

    PubMed

    Hayashi, Masanori; Zhao, Chunfeng; Thoreson, Andrew R; Chikenji, Takako; Jay, Gregory D; An, Kai-Nan; Amadio, Peter C

    2013-01-01

    The purpose of this study was to investigate the role of lubricin on the gliding resistance of intrasynovial tendons by comparing lubricin knockout, heterozygous, and wild type mice. A total of thirty-six deep digital flexor (DDF) tendons in the third digits of each hind paw from eighteen adult mice were used, including six lubricin knockout mice (Prg4 -/-), six heterozygous mice (Prg4 +/-), and six wild type mice (Prg4 +/+). The tendon gliding resistance was measured using a custom-made device. Tendon structural changes were evaluated by scanning electron and light microscopy. The gliding resistance of intrasynovial tendons from lubricin knockout mice was significantly higher than the gliding resistance of either wild type or heterozygous mice. The surface of the lubricin knockout tendons appeared to be rougher, compared to the wild type and heterozygous tendons. Synovial hyperplasia was found in the lubricin knockout mice. Cartilage-like tissue was found in the tendon and pulley of the lubricin knockout mice. Our findings confirm the importance of lubricin in intrasynovial tendon lubrication. This knockout model may be useful in determining the effect of lubricin on tendon healing and the response to injury.

  6. Achilles Tendon Rupture

    PubMed Central

    Wertz, Jess; Galli, Melissa; Borchers, James R.

    2013-01-01

    Context: Achilles tendon (AT) rupture in athletes is increasing in incidence and accounts for one of the most devastating sports injuries because of the threat to alter or end a career. Despite the magnitude of this injury, reliable risk assessment has not been clearly defined, and prevention strategies have been limited. The purpose of this review is to identify potential intrinsic and extrinsic risk factors for AT rupture in aerial and ground athletes stated in the current literature. Evidence Acquisition: A MEDLINE search was conducted on AT rupture, or “injury” and “risk factors” and “athletes” from 1980 to 2011. Emphasis was placed on epidemiology, etiology, and review articles focusing on the risk for lower extremity injury in runners and gymnasts. Thirty articles were reviewed, and 22 were included in this assessment. Results: Aerial and ground athletes share many intrinsic risk factors for AT rupture, including overuse and degeneration of the tendon as well as anatomical variations that mechanically put an athlete at risk. Older athletes, athletes atypical in size for their sport, high tensile loads, leg dominance, and fatigue also may increase risk. Aerial athletes tend to have more extrinsic factors that play a role in this injury due to the varying landing surfaces from heights and technical maneuvers performed at various skill levels. Conclusion: Risk assessment for AT rupture in aerial and ground athletes is multivariable and difficult in terms of developing prevention strategies. Quantitative measures of individual risk factors may help identify major contributors to injury. PMID:24427410

  7. Simultaneous bilateral patellar tendon rupture.

    PubMed

    Moura, Diogo Lino; Marques, José Pedro; Lucas, Francisco Manuel; Fonseca, Fernando Pereira

    2017-01-01

    Bilateral patellar tendon rupture is a rare entity, often associated with systemic diseases and patellar tendinopathy. The authors report a rare case of a 34-year-old man with simultaneous bilateral rupture of the patellar tendon caused by minor trauma. The patient is a retired basketball player with no past complaints of chronic knee pain and a history of steroid use. Surgical management consisted in primary end-to-end tendon repair protected temporarily with cerclage wiring, followed by a short immobilization period and intensive rehabilitation program. Five months after surgery, the patient was able to fully participate in sport activities.

  8. 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.

  9. Rectus Femoris Tendon Calcification

    PubMed Central

    Zini, Raul; Panascì, Manlio; Papalia, Rocco; Franceschi, Francesco; Vasta, Sebastiano; Denaro, Vincenzo

    2014-01-01

    Background: Since it was developed, hip arthroscopy has become the favored treatment for femoroacetabular impingement. Due to recent considerable improvements, the indications for this technique have been widely extended. Injuries of the rectus femoris tendon origin, after an acute phase, could result in a chronic tendinopathy with calcium hydroxyapatite crystal deposition, leading to pain and loss of function. Traditionally, this condition is addressed by local injection of anesthetic and corticosteroids or, when conservative measures fail, by open excision of the calcific lesion by an anterior approach. Purpose: To assess whether arthroscopic excision of calcification of the proximal rectus is a safe and effective treatment. Study Design: Case series; Level of evidence, 4. Methods: Outcomes were studied from 6 top amateur athletes (age range, 30-43 years; mean, 32.6 years) affected by calcification of the proximal rectus who underwent arthroscopic excision of the calcification. Patients were preoperatively assessed radiographically, and diagnosis was confirmed by a 3-dimensional computed tomography scan. To evaluate the outcome, standardized hip rating scores were used pre- and postoperatively (at 6 and 12 months): the Hip disability and Osteoarthritis Outcome Score, Oxford Hip Score, and Modified Harris Hip Score. Moreover, visual analog scales (VAS) for pain, sport activity level (SAL), and activities of daily living (ADL) were also used. Results: One year after surgery, all patients reported satisfactory outcomes, with 3 of 6 rating their return-to-sport level as high as preinjury level, and the remaining 3 with a percentage higher than 80%. Five patients ranked their ability to carry on daily activities at 100%. Statistical analysis showed significant improvement of the Oxford Hip Score, the Modified Harris Hip Score, and all 3 VAS subscales (pain, SAL, and ADL) from pre- to latest postoperative assessment (P < .05). Conclusion: Arthroscopic excision of

  10. 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.

  11. Management of Extensor Tendon Injuries

    PubMed Central

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

    2012-01-01

    Extensor tendon injuries are very common injuries, which inappropriately treated can cause severe lasting impairment for the patient. Assessment and management of flexor tendon injuries has been widely reviewed, unlike extensor injuries. It is clear from the literature that extensor tendon repair should be undertaken immediately but the exact approach depends on the extensor zone. Zone I injuries otherwise known as mallet injuries are often closed and treated with immobilisaton and conservative management where possible. Zone II injuries are again conservatively managed with splinting. Closed Zone III or ‘boutonniere’ injuries are managed conservatively unless there is evidence of displaced avulsion fractures at the base of the middle phalanx, axial and lateral instability of the PIPJ associated with loss of active or passive extension of the joint or failed non-operative treatment. Open zone III injuries are often treated surgically unless splinting enable the tendons to come together. Zone V injuries, are human bites until proven otherwise requires primary tendon repair after irrigation. Zone VI injuries are close to the thin paratendon and thin subcutaneous tissue which strong core type sutures and then splinting should be placed in extension for 4-6 weeks. Complete lacerations to zone IV and VII involve surgical primary repair followed by 6 weeks of splinting in extension. Zone VIII require multiple figure of eight sutures to repair the muscle bellies and static immobilisation of the wrist in 45 degrees of extension. To date there is little literature documenting the quality of repairing extensor tendon injuries however loss of flexion due to extensor tendon shortening, loss of flexion and extension resulting from adhesions and weakened grip can occur after surgery. This review aims to provide a systematic examination method for assessing extensor injuries, presentation and management of all type of extensor tendon injuries as well as guidance on

  12. Hyaluronic acid and tendon lesions

    PubMed Central

    Kaux, Jean-François; Samson, Antoine; Crielaard, Jean-Michel

    2015-01-01

    Summary Introduction recently, the viscoelastic properties of hyaluronic acid (HA) on liquid connective tissue have been proposed for the treatment of tendinopathies. Some fundamental studies show encouraging results on hyaluronic acid’s ability to promote tendon gliding and reduce adhesion as well as to improve tendon architectural organisation. Some observations also support its use in a clinical setting to improve pain and function. This literature review analyses studies relating to the use of hyaluronic acid in the treatment of tendinopathies. Methods this review was constructed using the Medline database via Pubmed, Scopus and Google Scholar. The key words hyaluronic acid, tendon and tendinopathy were used for the research. Results in total, 28 articles (in English and French) on the application of hyaluronic acid to tendons were selected for their relevance and scientific quality, including 13 for the in vitro part, 7 for the in vivo animal part and 8 for the human section. Conclusions preclinical studies demonstrate encouraging results: HA permits tendon gliding, reduces adhesions, creates better tendon architectural organisation and limits inflammation. These laboratory observations appear to be supported by limited but encouraging short-term clinical results on pain and function. However, controlled randomised studies are still needed. PMID:26958533

  13. Histomorphometric and ultrastructural analysis of the tendon-bone interface after rotator cuff repair in a rat model

    PubMed Central

    Kanazawa, Tomonoshin; Gotoh, Masafumi; Ohta, Keisuke; Honda, Hirokazu; Ohzono, Hiroki; Shimokobe, Hisao; Shiba, Naoto; Nakamura, Kei-ichiro

    2016-01-01

    Successful rotator cuff repair requires biological anchoring of the repaired tendon to the bone. However, the histological structure of the repaired tendon-bone interface differs from that of a normal tendon insertion. We analysed differences between the normal tendon insertion and the repaired tendon-bone interface after surgery in the mechanical properties, histomorphometric analysis, and 3-dimensional ultrastructure of the cells using a rat rotator cuff repair model. Twenty-four adult Sprague-Dawley (SD) rats underwent complete cuff tear and subsequent repair of the supraspinatus tendon. The repaired tendon-bone interface was evaluated at 4, 8, and 12 weeks after surgery. At each time point, shoulders underwent micro-computed tomography scanning and biomechanical testing (N = 6), conventional histology and histomorphometric analysis (N = 6), and ultrastructural analysis with focused ion beam/scanning electron microscope (FIB/SEM) tomography (N = 4). We demonstrated that the cellular distribution between the repaired tendon and bone at 12 weeks after surgery bore similarities to the normal tendon insertion. However, the ultrastructure of the cells at any time point had a different morphology than those of the normal tendon insertion. These morphological differences affect the healing process, partly contributing to re-tearing at the repair site. These results may facilitate future studies of the regeneration of a normal tendon insertion. PMID:27647121

  14. Correlations between mean echogenicity and material properties of normal and diseased equine superficial digital flexor tendons: an in vitro segmental approach.

    PubMed

    Crevier-Denoix, N; Ruel, Y; Dardillat, C; Jerbi, H; Sanaa, M; Collobert-Laugier, C; Ribot, X; Denoix, J-M; Pourcelot, P

    2005-11-01

    The objective of this study was to test the hypothesis that tendon echogenicity is associated with the material properties of the corresponding tendon site, especially in case of lesions, due to local changes in tendon matrix composition. Four normal and nine spontaneously injured equine superficial digital flexor tendons (SDFT) were isolated then ultrasonographically examined under tension, in a special device placed in a water bath. Ultrasonographic transversal images (7.5MHz linear transducer) of five segments along each tendon were digitized, and analyzed in order to measure the mean cross-sectional area (MCSA) and mean echogenicity (ME) of each segment. The tendons were then tested in traction until rupture in a testing machine. For each segment, stress and strain were determined throughout the test, and the elastic modulus (EM) was evaluated. The tendon lesions were also documented by histology. No correlation was found between ME and the material properties of normal tendon segments. At the rupture sites of the nine diseased tendons, ME was positively correlated with maximal stress and EM, whereas no correlation was demonstrated with maximal strain. Besides, a positive correlation was demonstrated between ME and both MCSA and EM, when the three metacarpal segments of the diseased tendons were considered. Although ME gives only rough information about tendon matrix structure, it does show, under these in vitro conditions, significant correlations with material properties of pathological tendon segments, which may improve the functional significance and therefore the prognostic value of the ultrasonographic examination of tendon lesions.

  15. Symptomatic intratendinous ganglion cyst of the patellar tendon.

    PubMed

    Jose, Jean; O'Donnell, Kevin; Lesniak, Bryson

    2011-01-01

    Ganglion cysts have been previously described throughout the body, most commonly about the wrist, hand, knee, ankle, and feet. When symptomatic, they may interfere with joint mechanics, resulting in snapping, catching, and locking. Intratendinous ganglion cysts lack a synovial epithelial lining and are thought to develop from the mucoid degeneration of connective tissue caused by chronic irritation, chronic repetitive injury, and chronic ischemia. On magnetic resonance imaging, ganglion cysts originating from tendons, ligaments, tendon sheaths, menisci, or joint capsules appear as well-defined lobulated masses that follow simple or complex fluid signal intensity on all pulse sequences, with enhancing walls and internal septations on post-contrast images. There may be appreciable degeneration and partial tearing of the structure of origin, particularly if associated with tendons. On ultrasonography, they present as hypoechoic masses, with internal septations and lobulations of varying sizes, without significant vascularity on power or color Doppler sampling. A thin fluid neck extending from the structure of origin (tail sign), when present, is a reliable sign of a ganglion cyst. This article describes a sonographically guided technique to treat symptomatic ganglion cysts within the patellar tendon. Complete evacuation of the ganglion cyst, with disappearance of the tail sign, is considered the determining factor for a successful procedure. A similar technique can be used for the treatment of other symptomatic intratendinous ganglion cysts elsewhere in the body. To our knowledge, symptomatic intratendinous ganglion cysts within the patellar tendon and their treatment have not been previously reported.

  16. Tendon Mechanobiology: Current Knowledge and Future Research Opportunities

    PubMed Central

    Lavagnino, Michael; Wall, Michelle E.; Little, Dianne; Banes, Albert J.; Guilak, Farshid; Arnoczky, Steven P.

    2015-01-01

    Tendons mainly function as load-bearing tissues in the muscloskeletal system, transmitting loads from muscle to bone. Tendons are dynamic structures that respond to the magnitude, direction, frequency, and duration of physiologic as well as pathologic mechanical loads via complex interactions between cellular pathways and the highly specialized extracellular matrix. This paper reviews the evolution and current knowledge of mechanobiology in tendon development, homeostasis, disease, and repair. In addition, we review several novel mechanotransduction pathways that have been identified recently in other tissues and cell types, providing potential research opportunities in the field of tendon mechanobiology. We also highlight current methods, models, and technologies being used in a wide variety of mechanobiology research that could be investigated in the context of their potential applicability for answering some of the fundamental unanswered questions in this field. The article concludes with a review of the major questions and future goals discussed during the recent ORS/ISMMS New Frontiers in Tendon Research Conference held September 10–11, 2014 in New York City. PMID:25763779

  17. 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

  18. Triceps tendon rupture in weight lifters.

    PubMed

    Sollender, J L; Rayan, G M; Barden, G A

    1998-01-01

    Triceps tendon avulsion injuries are rare. We report four weight lifters with triceps tendon raptures, two of whom had received local steroid injections for pain in the triceps. All four patients had taken oral anabolic steroids before injury. All patients had closed avulsion of the triceps tendon from its insertion into the olecranon. Three patients were injured while bench pressing heavy weights, and one patient was injured while swinging a baseball bat. Satisfactory results were achieved after surgical reinsertion of the tendon.

  19. Staged tendon grafts and soft tissue coverage.

    PubMed

    Elliot, David

    2011-05-01

    The objective of the two-staged flexor tendon method is to improve the predictability of final results in difficult problems dealing with tendon reconstruction. This article reviews the evolution and benefits of this procedure. It also considers the use of the technique to help deal with problems requiring pulley and skin reconstruction simultaneously with re-constituting the flexor tendon system.

  20. [Treatment of traumatic sections of the Achilles tendon].

    PubMed

    Orfanu, N

    1977-01-01

    The author maintains that the atrophy of the sural triceps muscle, the retraction of the Achille tendon and the osteoporosis of the calcaneum and of the tarsian bones, occurring after the traumatic sectioning of the Achille tendon, are the results of an inadequate treatment. The cause of these sequellae is the immobilization of the foot in an equinus position, which relaxes the sural triceps and as a result of the lack of mechanical traction factor, leads to local circulatory disturbances followed by a modification in the structure of the bone and of the muscle. On the basis of this pathophysiological concept the author has excluded post-operative immobilization in the equinus position, and in fact any type of immobilization, recommending in contrast a mobilization of the foot from the very first days after the suture of the tendon. The clinical results obtained confirm the value of the hypothesis.

  1. Achilles tendon reflex measuring system

    NASA Astrophysics Data System (ADS)

    Szebeszczyk, Janina; Straszecka, Joanna

    1995-06-01

    The examination of Achilles tendon reflex is widely used as a simple, noninvasive clinical test in diagnosis and pharmacological therapy monitoring in such diseases as: hypothyroidism, hyperthyroidism, diabetic neuropathy, the lower limbs obstructive angiopathies and intermittent claudication. Presented Achilles tendon reflect measuring system is based on the piezoresistive sensor connected with the cylinder-piston system. To determinate the moment of Achilles tendon stimulation a detecting circuit was used. The outputs of the measuring system are connected to the PC-based data acquisition board. Experimental results showed that the measurement accuracy and repeatability is good enough for diagnostics and therapy monitoring purposes. A user friendly, easy-to-operate measurement system fulfills all the requirements related to recording, presentation and storing of the patients' reflexograms.

  2. Tendon development and musculoskeletal assembly: emerging roles for the extracellular matrix

    PubMed Central

    Subramanian, Arul; Schilling, Thomas F.

    2015-01-01

    Tendons and ligaments are extracellular matrix (ECM)-rich structures that interconnect muscles and bones. Recent work has shown how tendon fibroblasts (tenocytes) interact with muscles via the ECM to establish connectivity and strengthen attachments under tension. Similarly, ECM-dependent interactions between tenocytes and cartilage/bone ensure that tendon-bone attachments form with the appropriate strength for the force required. Recent studies have also established a close lineal relationship between tenocytes and skeletal progenitors, highlighting the fact that defects in signals modulated by the ECM can alter the balance between these fates, as occurs in calcifying tendinopathies associated with aging. The dynamic fine-tuning of tendon ECM composition and assembly thus gives rise to the remarkable characteristics of this unique tissue type. Here, we provide an overview of the functions of the ECM in tendon formation and maturation that attempts to integrate findings from developmental genetics with those of matrix biology. PMID:26672092

  3. Mechanical factors in embryonic tendon development: Potential cues for stem cell tenogenesis

    PubMed Central

    Schiele, Nathan R.; Marturano, Joseph E.; Kuo, Catherine K.

    2013-01-01

    Tendons are connective tissues required for motion and are frequently injured. Poor healing and inadequate return to normal tissue structure and mechanical function make tendon a prime candidate for tissue engineering, however functional tendons have yet to be engineered. The physical environment, from substrate stiffness to dynamic mechanical loading, may regulate tenogenic stem cell differentiation. Tissue stiffness and loading parameters derived from embryonic development may enhance tenogenic stem cell differentiation and tendon tissue formation. We highlight current understanding of the mechanical environment experienced by embryonic tendons and how progenitor cells may sense and respond to physical inputs. We further discuss how mechanical factors have only recently been used to induce tenogenic fate in stem cells. PMID:23916867

  4. Mechanical factors in embryonic tendon development: potential cues for stem cell tenogenesis.

    PubMed

    Schiele, Nathan R; Marturano, Joseph E; Kuo, Catherine K

    2013-10-01

    Tendons are connective tissues required for motion and are frequently injured. Poor healing and inadequate return to normal tissue structure and mechanical function make tendon a prime candidate for tissue engineering; however functional tendons have yet to be engineered. The physical environment, from substrate stiffness to dynamic mechanical loading, may regulate tenogenic stem cell differentiation. Tissue stiffness and loading parameters derived from embryonic development may enhance tenogenic stem cell differentiation and tendon tissue formation. We highlight the current understanding of the mechanical environment experienced by embryonic tendons and how progenitor cells may sense and respond to physical inputs. We further discuss how mechanical factors have only recently been used to induce tenogenic fate in stem cells.

  5. Stochastic Interdigitation as a Toughening Mechanism at the Interface between Tendon and Bone

    PubMed Central

    Hu, Yizhong; Birman, Victor; Demyier-Black, Alix; Schwartz, Andrea G.; Thomopoulos, Stavros; Genin, Guy M.

    2015-01-01

    Reattachment and healing of tendon to bone poses a persistent clinical challenge and often results in poor outcomes, in part because the mechanisms that imbue the uninjured tendon-to-bone attachment with toughness are not known. One feature of typical tendon-to-bone surgical repairs is direct attachment of tendon to smooth bone. The native tendon-to-bone attachment, however, presents a rough mineralized interface that might serve an important role in stress transfer between tendon and bone. In this study, we examined the effects of interfacial roughness and interdigital stochasticity on the strength and toughness of a bimaterial interface. Closed form linear approximations of the amplification of stresses at the rough interface were derived and applied in a two-dimensional unit-cell model. Results demonstrated that roughness may serve to increase the toughness of the tendon-to-bone insertion site at the expense of its strength. Results further suggested that the natural tendon-to-bone attachment presents roughness for which the gain in toughness outweighs the loss in strength. More generally, our results suggest a pathway for stochasticity to improve surgical reattachment strategies and structural engineering attachments. PMID:25606690

  6. The clinical effect of tendon repair for tendon spontaneous rupture after corticosteroid injection in hands

    PubMed Central

    Lu, Hui; Yang, Hu; Shen, Hui; Ye, Ganmin; Lin, Xiang-Jin

    2016-01-01

    Abstract Corticosteroid injections for hand tendinitis can lead to a rare significant complication of tendon spontaneous rupture. However, only sporadic cases were reported in the literature before. This study was designed to gauge the clinical effect of tendon repair in patients of tendon spontaneous rupture after corticosteroid injection and analyze our experience. This was a retrospective observational study of 13 patients (8 women and 5 men) operated between July 2011 and December 2015 for tendon spontaneous rupture after corticosteroid injection. Demographic data, clinical features, imaging data, and surgical treatments were carefully reviewed. The average age was 52.308 ± 15.381 years (range 29–71). The average injection times were 2.538 ± 1.664 times (range 1–6). The average rupture time (after last injection) was 10.923 ± 9.500 weeks (range 3–32). Nine patients were treated by tendon suture (69% of cases), and 4 patients were treated by tendon grafting (31% of cases). All patients received follow-up in our outpatient clinic. The sites of the tendon rupture (15 tendons of 13 patients had involved) include extensor pollicis longus (6 tendons, 40% of cases), extensor digiti quinti and extensor digiti minimi (4 tendons, 27% of cases), ring finger of extensor digitorum communis (3 tendons, 20% of cases), and middle finger of extensor digitorum communis (2 tendons, 13% of cases). Two patients who had tendon adhesion (15% of cases) were treated by tendon release. One patient who had tendon rerupture (8% of cases) was treated by tendon grafting. No patient had complications of infections, vascular, or nerve injury. Tendon spontaneous rupture is a serious complication after corticosteroid injection for tendinitis. Rigid standard of corticosteroid injection is very important. Magnetic resonance imaging was contributory to preoperative assess tendon defect and can be used to monitor healing quality of tendons during the follow-up. PMID:27741145

  7. 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

  8. Biaxial tensile testing and constitutive modeling of human supraspinatus tendon.

    PubMed

    Szczesny, Spencer E; Peloquin, John M; Cortes, Daniel H; Kadlowec, Jennifer A; Soslowsky, Louis J; Elliott, Dawn M

    2012-02-01

    The heterogeneous composition and mechanical properties of the supraspinatus tendon offer an opportunity for studying the structure-function relationships of fibrous musculoskeletal connective tissues. Previous uniaxial testing has demonstrated a correlation between the collagen fiber angle distribution and tendon mechanics in response to tensile loading both parallel and transverse to the tendon longitudinal axis. However, the planar mechanics of the supraspinatus tendon may be more appropriately characterized through biaxial tensile testing, which avoids the limitation of nonphysiologic traction-free boundary conditions present during uniaxial testing. Combined with a structural constitutive model, biaxial testing can help identify the specific structural mechanisms underlying the tendon's two-dimensional mechanical behavior. Therefore, the objective of this study was to evaluate the contribution of collagen fiber organization to the planar tensile mechanics of the human supraspinatus tendon by fitting biaxial tensile data with a structural constitutive model that incorporates a sample-specific angular distribution of nonlinear fibers. Regional samples were tested under several biaxial boundary conditions while simultaneously measuring the collagen fiber orientations via polarized light imaging. The histograms of fiber angles were fit with a von Mises probability distribution and input into a hyperelastic constitutive model incorporating the contributions of the uncrimped fibers. Samples with a wide fiber angle distribution produced greater transverse stresses than more highly aligned samples. The structural model fit the longitudinal stresses well (median R(2) ≥ 0.96) and was validated by successfully predicting the stress response to a mechanical protocol not used for parameter estimation. The transverse stresses were fit less well with greater errors observed for less aligned samples. Sensitivity analyses and relatively affine fiber kinematics suggest that

  9. Distribution and expression of type VI collagen and elastic fibers in human rotator cuff tendon tears.

    PubMed

    Thakkar, Dipti; Grant, Tyler M; Hakimi, Osnat; Carr, Andrew J

    2014-01-01

    There is increasing evidence for a progressive extracellular matrix change in rotator cuff disease progression. Directly surrounding the cell is the pericellular matrix, where assembly of matrix aggregates typically occurs making it critical in the response of tendon cells to pathological conditions. Studies in animal models have identified type VI collagen, fibrillin-1 and elastin to be located in the pericellular matrix of tendon and contribute in maintaining the structural and biomechanical integrity of tendon. However, there have been no reports on the localization of these proteins in human tendon biopsies. This study aimed to characterize the distribution of these ECM components in human rotator cuffs and gain greater insight into the relationship of pathology to tear size by analyzing the distribution and expression profiles of these ECM components. Confocal microscopy confirmed the localization of these structural molecules in the pericellular matrix of the human rotator cuff. Tendon degeneration led to an increased visibility of these components with a significant disorganization in the distribution of type VI collagen. At the genetic level, an increase in tear size was linked to an increased transcription of type VI collagen and fibrillin-1 with no significant alteration in the elastin levels. This is the first study to confirm the localization of type VI collagen, elastin and fibrillin-1 in the pericellular region of human supraspinatus tendon and assesses the effect of tendon degeneration on these structures, thus providing a useful insight into the composition of human rotator cuff tears which can be instrumental in predicting disease prognosis.

  10. Ultrasound elasticity imaging of human posterior tibial tendon

    NASA Astrophysics Data System (ADS)

    Gao, Liang

    Posterior tibial tendon dysfunction (PTTD) is a common degenerative condition leading to a severe impairment of gait. There is currently no effective method to determine whether a patient with advanced PTTD would benefit from several months of bracing and physical therapy or ultimately require surgery. Tendon degeneration is closely associated with irreversible degradation of its collagen structure, leading to changes to its mechanical properties. If these properties could be monitored in vivo, it could be used to quantify the severity of tendonosis and help determine the appropriate treatment. Ultrasound elasticity imaging (UEI) is a real-time, noninvasive technique to objectively measure mechanical properties in soft tissue. It consists of acquiring a sequence of ultrasound frames and applying speckle tracking to estimate displacement and strain at each pixel. The goals of my dissertation were to 1) use acoustic simulations to investigate the performance of UEI during tendon deformation with different geometries; 2) develop and validate UEI as a potentially noninvasive technique for quantifying tendon mechanical properties in human cadaver experiments; 3) design a platform for UEI to measure mechanical properties of the PTT in vivo and determine whether there are detectable and quantifiable differences between healthy and diseased tendons. First, ultrasound simulations of tendon deformation were performed using an acoustic modeling program. The effects of different tendon geometries (cylinder and curved cylinder) on the performance of UEI were investigated. Modeling results indicated that UEI accurately estimated the strain in the cylinder geometry, but underestimated in the curved cylinder. The simulation also predicted that the out-of-the-plane motion of the PTT would cause a non-uniform strain pattern within incompressible homogeneous isotropic material. However, to average within a small region of interest determined by principal component analysis (PCA

  11. Characterization and comparison of post-natal rat Achilles tendon-derived stem cells at different development stages.

    PubMed

    Chen, Jialin; Zhang, Wei; Liu, Zeyu; Zhu, Ting; Shen, Weiliang; Ran, Jisheng; Tang, Qiaomei; Gong, Xiaonan; Backman, Ludvig J; Chen, Xiao; Chen, Xiaowen; Wen, Feiqiu; Ouyang, Hongwei

    2016-03-14

    Tendon stem/progenitor cells (TSPCs) are a potential cell source for tendon tissue engineering. The striking morphological and structural changes of tendon tissue during development indicate the complexity of TSPCs at different stages. This study aims to characterize and compare post-natal rat Achilles tendon tissue and TSPCs at different stages of development. The tendon tissue showed distinct differences during development: the tissue structure became denser and more regular, the nuclei became spindle-shaped and the cell number decreased with time. TSPCs derived from 7 day Achilles tendon tissue showed the highest self-renewal ability, cell proliferation, and differentiation potential towards mesenchymal lineage, compared to TSPCs derived from 1 day and 56 day tissue. Microarray data showed up-regulation of several groups of genes in TSPCs derived from 7 day Achilles tendon tissue, which may account for the unique cell characteristics during this specific stage of development. Our results indicate that TSPCs derived from 7 day Achilles tendon tissue is a superior cell source as compared to TSPCs derived from 1 day and 56 day tissue, demonstrating the importance of choosing a suitable stem cell source for effective tendon tissue engineering and regeneration.

  12. 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

  13. An Improved Force Feedback Control Algorithm for Active Tendons

    PubMed Central

    Guo, Tieneng; Liu, Zhifeng; Cai, Ligang

    2012-01-01

    An active tendon, consisting of a displacement actuator and a co-located force sensor, has been adopted by many studies to suppress the vibration of large space flexible structures. The damping, provided by the force feedback control algorithm in these studies, is small and can increase, especially for tendons with low axial stiffness. This study introduces an improved force feedback algorithm, which is based on the idea of velocity feedback. The algorithm provides a large damping ratio for space flexible structures and does not require a structure model. The effectiveness of the algorithm is demonstrated on a structure similar to JPL-MPI. The results show that large damping can be achieved for the vibration control of large space structures. PMID:23112660

  14. Evidence against proteoglycan mediated collagen fibril load transmission and dynamic viscoelasticity in tendon.

    PubMed

    Fessel, Gion; Snedeker, Jess G

    2009-10-01

    The glycosaminoglycan (GAG) dermatan sulfate and chondroitin sulfate side-chains of small leucine-rich proteoglycans have been increasingly posited to act as molecular cross links between adjacent collagen fibrils and to directly contribute to tendon elasticity. GAGs have also been implicated in tendon viscoelasticity, supposedly affecting frictional loss during elongation or fluid flow through the extra cellular matrix. The current study sought to systematically test these theories of tendon structure-function by investigating the mechanical repercussions of enzymatic depletion of GAG complexes by chondroitinase ABC in a reproducible tendon structure-function model (rat tail tendon fascicles). The extent of GAG removal (at least 93%) was verified by relevant spectrophotometric assays and transmission electron microscopy. Dynamic viscoelastic tensile tests on GAG depleted rat tail tendon fascicle were not mechanically different from controls in storage modulus (elastic behavior) over a wide range of strain-rates (0.05, 0.5, and 5% change in length per second) in either the linear or nonlinear regions of the material curve. Loss modulus (viscoelastic behavior) was only affected in the nonlinear region at the highest strain-rate, and even this effect was marginal (19% increased loss modulus, p=0.035). Thus glycosaminoglycan chains of small leucine-rich proteoglycans do not appear to mediate dynamic elastic behavior nor do they appear to regulate the dynamic viscoelastic properties in rat tail tendon fascicles.

  15. In-vitro tensile testing machine for vibration study of fresh rabbit Achilles tendon

    NASA Astrophysics Data System (ADS)

    Revel, Gian M.; Scalise, Alessandro; Scalise, Lorenzo; Pianosi, Antonella

    2001-10-01

    A lot of people, overall athletic one suffer from tendinitis or complete rupture of the Achilles tendon. This structure becomes inflamed and damaged mainly from a variety of mechanical forces and sometimes due to metabolic problems, such as diabetes or arthritis. Over the past three decades extensive studies have been performed on the structural and mechanical properties of Achilles tendon trying to explain the constitutive equations to describe and foresee tendon behavior. Among the various mechanical parameters, the vibrational behavior is also of interest. Several investigations are performed in order to study how the Achilles tendon vibrations influence the response of the muscle proprioception and human posture. The present article describes how in vitro tensile experiments can be performed, taking into account the need to simulate physiological condition of Achilles tendon and thus approaching some opened problems in the design of the experimental set-up. A new system for evaluating tendon vibrations by non contact techniques is proposed. Preliminary simple elongation tests are made extracting the main mechanical parameters: stress and strain at different fixed stretches, in order to characterize the tissue. Finally, a vibration study is made at each pretensioned tendon level evaluating the oscillating curves caused by a small hammer.

  16. Informing tendon tissue engineering with embryonic development.

    PubMed

    Glass, Zachary A; Schiele, Nathan R; Kuo, Catherine K

    2014-06-27

    Tendon is a strong connective tissue that transduces muscle-generated forces into skeletal motion. In fulfilling this role, tendons are subjected to repeated mechanical loading and high stress, which may result in injury. Tissue engineering with stem cells offers the potential to replace injured/damaged tissue with healthy, new living tissue. Critical to tendon tissue engineering is the induction and guidance of stem cells towards the tendon phenotype. Typical strategies have relied on adult tissue homeostatic and healing factors to influence stem cell differentiation, but have yet to achieve tissue regeneration. A novel paradigm is to use embryonic developmental factors as cues to promote tendon regeneration. Embryonic tendon progenitor cell differentiation in vivo is regulated by a combination of mechanical and chemical factors. We propose that these cues will guide stem cells to recapitulate critical aspects of tenogenesis and effectively direct the cells to differentiate and regenerate new tendon. Here, we review recent efforts to identify mechanical and chemical factors of embryonic tendon development to guide stem/progenitor cell differentiation toward new tendon formation, and discuss the role this work may have in the future of tendon tissue engineering.

  17. Informing tendon tissue engineering with embryonic development

    PubMed Central

    Glass, Zachary A.; Schiele, Nathan R.; Kuo, Catherine K.

    2014-01-01

    Tendon is a strong connective tissue that transduces muscle-generated forces into skeletal motion. In fulfilling this role, tendons are subjected to repeated mechanical loading and high stress, which may result in injury. Tissue engineering with stem cells offers the potential to replace injured/damaged tissue with healthy, new living tissue. Critical to tendon tissue engineering is the induction and guidance of stem cells towards the tendon phenotype. Typical strategies have relied on adult tissue homeostatic and healing factors to influence stem cell differentiation, but have yet to achieve tissue regeneration. A novel paradigm is to use embryonic developmental factors as cues to promote tendon regeneration. Embryonic tendon progenitor cell differentiation in vivo is regulated by a combination of mechanical and chemical factors. We propose that these cues will guide stem cells to recapitulate critical aspects of tenogenesis and effectively direct the cells to differentiate and regenerate new tendon. Here, we review recent efforts to identify mechanical and chemical factors of embryonic tendon development to guide stem/progenitor cell differentiation toward new tendon formation, and discuss the role this work may have in the future of tendon tissue engineering. PMID:24484642

  18. Interaction between gastrocnemius medialis fascicle and Achilles tendon compliance: a new insight on the quick-release method.

    PubMed

    Farcy, Stevy; Nordez, Antoine; Dorel, Sylvain; Hauraix, Hugo; Portero, Pierre; Rabita, Giuseppe

    2014-02-01

    The insufficient temporal resolution of imaging devices has made the analysis of very fast movements, such as those required to measure active muscle-tendon unit stiffness, difficult. Thus the relative contributions of tendon, aponeurosis, and fascicle to muscle-tendon unit compliance remain to be determined. The present study analyzed the dynamic interactions of fascicle, tendon, and aponeurosis in human gastrocnemius medialis during the first milliseconds of an ankle quick-release movement, using high-frame-rate ultrasonography (2,000 frames/s). Nine subjects performed the tests in random order at six levels of maximal voluntary contraction (MVC) (30% to 80% of MVC). These tests were carried out with the ultrasound probe placed on the muscle belly and on the myotendinous junction. Tendon, muscle fascicle, and aponeurosis length changes were quantified in relation to shortening of the muscle-tendon unit during the first few milliseconds following the release. The tendon was the main contributor (around 72%) to the shortening of the muscle-tendon unit, whereas the muscle fascicle and aponeurosis contributions were 18% and 10%, respectively. Because these structures can be considered in series, the quantified contributions can be regarded as relative contributions to muscle-tendon compliance. These contributions were not modified with the level of MVC or the time range used for the analysis between 10 and 25 ms. The constant contribution of tendon, muscle fascicle, and aponeurosis to muscle-tendon unit compliance may help to simplify the mechanism of compliance regulation and to maintain the important role of tendons in enhancing work output and movement efficiency.

  19. Overweight and obesity alters the cumulative transverse strain in the Achilles tendon immediately following exercise.

    PubMed

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

    2013-07-01

    This research evaluated the effect of obesity on the acute cumulative transverse strain of the Achilles tendon in response to exercise. Twenty healthy adult males were categorized into 'low normal-weight' (BMI <23 kg m(-2)) and 'overweight' (BMI >27.5 kg m(-2)) groups based on intermediate cut-off points recommended by the World Health Organization. Longitudinal sonograms of the right Achilles tendon were acquired immediately prior and following weight-bearing ankle exercises. Achilles tendon thickness was measured 20-mm proximal to the calcaneal insertion and transverse tendon strain was calculated as the natural log of the ratio of post- to pre-exercise tendon thickness. The Achilles tendon was thicker in the overweight group both prior to (t18 = -2.91, P = 0.009) and following (t18 = -4.87, P < 0.001) exercise. The acute transverse strain response of the Achilles tendon in the overweight group (-10.7 ± 2.5%), however, was almost half that of the 'low normal-weight' (-19.5 ± 7.4%) group (t18 = -3.56, P = 0.004). These findings suggest that obesity is associated with structural changes in tendon that impairs intra-tendinous fluid movement in response to load and provides new insights into the link between tendon pathology and overweight and obesity.

  20. 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

  1. Torn human rotator cuff tendons have reduced collagen thermal properties on differential scanning calorimetry.

    PubMed

    Chaudhury, Salma; Holland, Christopher; Porter, David; Tirlapur, Uday K; Vollrath, Fritz; Carr, Andrew J

    2011-12-01

    The cause of the high failure rates often observed following rotator cuff tendon repairs, particularly massive tears, is not fully understood. Collagen structural changes have been shown to alter tendon thermal and mechanical properties. This study aimed to form a quantitative rather than qualitative assessment, of whether differences in collagen structure and integrity existed between small biopsies of normal, small, and massive rotator cuff tears using differential scanning calorimetry. Thermal properties were measured for 28 human biopsies taken intra-operatively from normal, small, and massive rotator cuff tendon tears in this powered study. Denaturation temperatures are represented by T(onset) (°C) and T(peak) (°C). The T(onset) is proposed to represent water-amide hydrogen bond breakage and resulting protein backbone mobility. T(peak) reportedly corresponds to the temperature at which the majority of proteins fall out of solution. Denaturation enthalpy (ΔH) should correlate with the amount of triple helical structure that is denatured. Fluorescence and confocal microscopy allowed quantitative validation. Small and massive rotator cuff tears had significantly higher T(onset), T(peak), and ΔH compared to controls. Polarized light microscopy of torn tendons confirmed greater collagen structural disruption compared to controls. These novel findings suggest greater quantifiable collagen structural disruption in rotator cuff tears, compared to controls. This study offers insight into possible mechanisms for the reduced strength of torn tendons and may explain why repaired tendons fail to heal.

  2. Prestressed concrete using KEVLAR reinforced tendons

    SciTech Connect

    Dolan, C.W.

    1989-01-01

    KEVLAR is a high strength, high modulus synthetic fiber manufactured by the E.I. DuPont de Nemours Company. The fiber is resistant to chloride and alkali attack. The resistance is enhanced when the fibers are assembled into a resin matrix and fabricated as rods. These properties suggest that KEVLAR reinforced rods may be a substitute for high strength steel prestress tendons in certain applications such as bridge decks and parking structures. This dissertation presents the background, theoretical development, and experimental investigations of KEVLAR reinforced rod strength, anchorage, fabrication and performance in prestressed concrete structures. The study concludes that KEVLAR has significant potential for these prestressed concrete applications. However, the reliability of the long term anchorage of the KEVLAR reinforced rods must be improved before production applications are undertaken. KEVLAR has a low shear strength compared to its tensile capacity. The anchorage of KEVLAR reinforced rods is sensitive to the shear forces generated in the anchorage assembly. Finite element analyses, using interface elements to simulate the addition of a mold release agent in a conic anchor, predict the behavior of resin socketed anchors. Test results confirm that mold release agents reduce the anchor shear stresses and suggest that moderate strength resins may be used in the anchor. KEVLAR is nearly linearly elastic to failure, yet ductility of a structure is an important design concern. Prestressed concrete beam tests using both bonded and unbonded tendons demonstrated that ductile structural behavior is obtained. Methods of predicting the strength and deflection behavior of the prestressed beams are presented and the theoretical predictions are compared to the experimental results. The overall correlation between predicted and theoretical results is satisfactory.

  3. Bifurcated popliteus tendon: a descriptive arthroscopic study

    PubMed Central

    Ginés-Cespedosa, Albert; Monllau, Joan C.

    2008-01-01

    The objective of this study was to confirm the presence and frequency of a bifurcation of the popliteus tendon. The popliteus tendon has received attention due to its important function as a knee stabiliser. Several anatomical variants have recently been reported, one of them being a bifurcated tendon. However, the actual frequency as well as the possible role of this particular variant is still unknown. We prospectively analysed a series of 1,569 arthroscopies between January 2005 to December 2007. Six asymptomatic bifurcated popliteus tendons were found. No alterations in the magnetic resonance imaging were seen and no clinical signs (related to the popliteus tendon) were observed in these patients before surgery. In all cases the morphological variant was found by chance. Our results suggest that the presence of a bifurcated popliteus tendon is a fact and that its frequency, not previously reported, should not be ignored. PMID:18998130

  4. Autonomy of tendon development in the embryonic chick wing.

    PubMed

    Kieny, M; Chevallier, A

    1979-01-01

    The aim of this study performed in the embryonic chick wing is to test the ability of the tendons to form and develop in the absence of the muscle bellies. The experiments were performed on 2-day chick embryos by destroying a portion of the somitic mesoderm by local X-irradiation. The irradiated part included the wing somite level 15-20 and extended three somites (or presumptive somites) in front and two to six presumptive somites in the rear of the wing somite levels. The wings of the operated side were examined histologically 3-8 days after the X-irradiation. The radio-destruction of the somitic mesoderm totally inhibited or severely impaired the development of the forearm muscles. But, despite the absence of the flexor and extensor muscles the differentiation of the distal manus tendons could be observed. This differentiation occurred at the same time and in the same positions as in controls. However, these tendons were transient structures. They disappeared within three days after their individuation. Two mechanisms that progressed in proximo-distal direction were involved in their resorption: cellular dislocation and cell death. We conclude that tendons start to develop autonomously from the muscle bulks, but for their maintenance and further development they require connexion to a muscle belly.

  5. [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.

  6. 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.

  7. Tendon Based Full Size Biped Humanoid Robot Walking Platform Design

    NASA Astrophysics Data System (ADS)

    Kuo, Chung-Hsien; Chiou, Kuo-Wei

    Actuators and gear trains of most biped humanoid robots are divergently allocated on the links of two legs. Disadvantages of such a mechanical design are complicated wiring of power cord and sensing/ control signal bundles and imprecise kinetics models of mixed link-and-actuator structures. Based on these drawbacks, this paper proposes a tendon-driven mechanism to develop a lower body structure of a full-size biped humanoid robot. The actuators are compacted as an actuator module, and they are placed at a distal site. A 12 degree-of-freedom mechanical structure is proposed with 100 cm in height and 45 kg in weight. The gait planning module is simulated and evaluated using the Matlab software. At the same time, an ARM7 based controller is developed to automatically generate walking patterns as well as to control the motors. Finally, a tendon-driven biped humanoid robot prototype is realized for practical waling control in the future.

  8. Study of Bone Marrow Mesenchymal and Tendon-Derived Stem Cells Transplantation on the Regenerating Effect of Achilles Tendon Ruptures in Rats

    PubMed Central

    Al-ani, Mohanad Kh; Xu, Kang; Sun, Yanjun; Pan, Lianhong; Xu, ZhiLing; Yang, Li

    2015-01-01

    Comparative therapeutic significance of tendon-derived stem cells (TDSCs) and bone marrow mesenchymal stem cells (BMSCs) transplantation to treat ruptured Achilles tendon was studied. Three groups of SD rats comprising 24 rats each, designated as TDSCs and BMSCs, and nontreated were studied for regenerative effects through morpho-histological evaluations and ultimate failure load. For possible mechanism in tendon repair/regeneration through TDSCs and BMSCs, we measured Collagen-I (Col-I), Col-III gene expression level by RT-PCR, and Tenascin-C expression via immunofluorescent assay. TDSCs showed higher agility in tendon healing with better appearance density and well-organized longitudinal fibrous structure, though BMSCs also showed positive effects. Initially the ultimate failure load was considerably higher in TDSCs than other two study groups during the weeks 1 and 2, but at week 4 it attained an average or healthy tendon strength of 30.2 N. Similar higher tendency in Col-I/III gene expression level during weeks 1, 2, and 4 was observed in TDSCs treated group with an upregulation of 1.5-fold and 1.1-fold than the other two study groups. Immunofluorescent assay revealed higher expression of Tenascin-C in TDSCs at week 1, while both TDSCs and BMSCs treated groups showed detectable CM-Dil-labelled cells at week 4. Compared with BMSCs, TDSCs showed higher regenerative potential while treating ruptured Achilles tendons in rats. PMID:26339252

  9. Lineage tracing of resident tendon progenitor cells during growth and natural healing.

    PubMed

    Dyment, Nathaniel A; Hagiwara, Yusuke; Matthews, Brya G; Li, Yingcui; Kalajzic, Ivo; Rowe, David W

    2014-01-01

    Unlike during embryogenesis, the identity of tissue resident progenitor cells that contribute to postnatal tendon growth and natural healing is poorly characterized. Therefore, we utilized 1) an inducible Cre driven by alpha smooth muscle actin (SMACreERT2), that identifies mesenchymal progenitors, 2) a constitutively active Cre driven by growth and differentiation factor 5 (GDF5Cre), a critical regulator of joint condensation, in combination with 3) an Ai9 Cre reporter to permanently label SMA9 and GDF5-9 populations and their progeny. In growing mice, SMA9+ cells were found in peritendinous structures and scleraxis-positive (ScxGFP+) cells within the tendon midsubstance and myotendinous junction. The progenitors within the tendon midsubstance were transiently labeled as they displayed a 4-fold expansion from day 2 to day 21 but reduced to baseline levels by day 70. SMA9+ cells were not found within tendon entheses or ligaments in the knee, suggesting a different origin. In contrast to the SMA9 population, GDF5-9+ cells extended from the bone through the enthesis and into a portion of the tendon midsubstance. GDF5-9+ cells were also found throughout the length of the ligaments, indicating a significant variation in the progenitors that contribute to tendons and ligaments. Following tendon injury, SMA9+ paratenon cells were the main contributors to the healing response. SMA9+ cells extended over the defect space at 1 week and differentiated into ScxGFP+ cells at 2 weeks, which coincided with increased collagen signal in the paratenon bridge. Thus, SMA9-labeled cells represent a unique progenitor source that contributes to the tendon midsubstance, paratenon, and myotendinous junction during growth and natural healing, while GDF5 progenitors contribute to tendon enthesis and ligament development. Understanding the mechanisms that regulate the expansion and differentiation of these progenitors may prove crucial to improving future repair strategies.

  10. 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.

  11. Morphology and Histology of Lower Limb Tendons and Ligaments in Primates.

    DTIC Science & Technology

    1981-08-01

    dlllerent from Report) IS. SUPPLEMENTARY NOTES 19. KEY WORDS (Continue on revermo sidIft neceses end Identify by block ntmbe) Tendon Plantar Osseo-fibrous...ligaments were sanded smooth to facilitate the utilization of mechanical testing grips. Dissection of the Foot: The plantar aspect of the foot was...removed to expose the inner structures. The tendo-calcaneus tendon was dissected first and was freed of fascia from the gastrocnemius muscle to the

  12. Endoscopic Loose Body Removal From Zone 2 Flexor Hallucis Longus Tendon Sheath.

    PubMed

    Lui, Tun Hing

    2016-06-01

    Tenosynovial chondromatosis can occur in the flexor hallucis longus tendon sheath. Complete synovectomy and removal of the loose bodies comprise the treatment of choice. An open procedure requires extensive soft-tissue dissection because the flexor hallucis longus tendon is a deep structure except at the hallux. A tendoscopy approach to synovectomy and removal of loose bodies has the advantage of minimally invasive surgery. This technical note outlines pearls and pitfalls and provides a step-by-step guide to performing this procedure.

  13. Passive mechanical properties of human gastrocnemius muscle tendon units, muscle fascicles and tendons in vivo.

    PubMed

    Hoang, P D; Herbert, R D; Todd, G; Gorman, R B; Gandevia, S C

    2007-12-01

    This study provides the first in vivo measures of the passive length-tension properties of relaxed human muscle fascicles and their tendons. A new method was used to derive passive length-tension properties of human gastrocnemius muscle-tendon units from measures of ankle stiffness obtained at a range of knee angles. Passive length-tension curves of the muscle-tendon unit were then combined with ultrasonographic measures of muscle fascicle length and pennation to determine passive length-tension curves of the muscle fascicles and tendons. Mean slack lengths of the fascicles, tendons and whole muscle-tendon units were 3.3+/-0.5 cm, 39.5+/-1.6 cm and 42.3+/-1.5 cm, respectively (means +/- s.d., N=6). On average, the muscle-tendon units were slack (i.e. their passive tension was zero) over the shortest 2.3+/-1.2 cm of their range. With combined changes of knee and ankle angles, the maximal increase in length of the gastrocnemius muscle-tendon unit above slack length was 6.7+/-1.9 cm, of which 52.4+/-11.7% was due to elongation of the tendon. Muscle fascicles and tendons underwent strains of 86.4+/-26.8% and 9.2+/-4.1%, respectively, across the physiological range of lengths. We conclude that the relaxed human gastrocnemius muscle-tendon unit falls slack over about one-quarter of its in vivo length and that muscle fascicle strains are much greater than tendon strains. Nonetheless, because the tendons are much longer than the muscle fascicles, tendons contribute more than half of the total compliance of the muscle-tendon unit.

  14. The impact of rotator cuff deficiency on structure, mechanical properties, and gene expression profiles of the long head of the biceps tendon (LHBT): Implications for management of the LHBT during primary shoulder arthroplasty.

    PubMed

    Kurdziel, Michael D; Moravek, James E; Wiater, Brett P; Davidson, Abigail; Seta, Joseph; Maerz, Tristan; Baker, Kevin C; Wiater, J Michael

    2015-08-01

    The long head of the biceps tendon (LHBT) occupies a unique proximal intra-articular and distal extra-articular position within the human shoulder. In the presence of a rotator cuff (RC) tear, the LHBT is recruited into an accelerated role undergoing potential mechanical and biochemical degeneration. Intra-articular sections of the LHBT were harvested during primary shoulder arthroplasty from patients with an intact or deficient RC. LHBTs were stained (H&E, Alcian Blue) and subjected to histologic analysis using the semiquantitative Bonar scale and measurement of collagen orientation. LHBTs (n = 12 per group) were also subjected to gene-expression analyses via an RT(2) -PCR Profiler Array quantifying 84 genes associated with cell-cell and cell-matrix interactions. LHBTs (n = 18 per group) were biomechanically tested with both stress-relaxation and load-to-failure protocols and subsequently modeled with the Quasilinear Viscoelastic (QLV) and Structural-Based Elastic (SBE) models. While no histologic differences were observed, significant differences in mechanical testing, and viscoelastic modeling parameters were found. PCR arrays identified five genes that were differentially expressed between RC-intact and RC-deficient LHBT groups. LHBTs display signs of pathology regardless of RC status in the arthroplasty population, which may be secondary to both glenohumeral joint arthritis and the additional mechanical role of the LHBT in this population.

  15. Tendon Adaptation to Sport-specific Loading in Adolescent Athletes.

    PubMed

    Cassel, M; Carlsohn, A; Fröhlich, K; John, M; Riegels, N; Mayer, F

    2016-02-01

    Tendon adaptation due to mechanical loading is controversially discussed. However, data concerning the development of tendon thickness in adolescent athletes is sparse. The purpose of this study was to examine possible differences in Achilles (AT) and patellar tendon (PT) thickness in adolescent athletes while considering age, gender and sport-specific loading. In 500 adolescent competitive athletes of 16 different sports and 40 recreational controls both ATs and PTs were sonographically measured. Subjects were divided into 2 age groups (< 13; ≥ 13 years) and 6 sport type categories (ball, combat, and water sports, combined disciplines, cycling, controls). In addition, 3 risk groups (low, moderate, high) were created according to the athlete's risk of developing tendinopathy. AT and PT thickness did not significantly differ between age groups (AT/PT:<13: 5.4±0.7 mm/3.6±0.5 mm;≥13: 5.3±0.7 mm/3.6±0.5 mm). In both age groups males presented higher tendon thickness than females (p<0.001). AT thickness was highest in ball sports/cyclists and lowest in controls (p≤0.002). PT thickness was greatest in water sports and lowest in controls (p=0.02). High risk athletes presented slightly higher AT thickness compared to the low risk group (p=0.03). Increased AT and PT thickness in certain sport types compared to controls supports the hypothesis of structural tendon adaptation due to sport-specific loading.

  16. Tendon mineralization is accelerated bilaterally and creep of contralateral tendons is increased after unilateral needle injury of murine achilles tendons.

    PubMed

    O'Brien, Etienne John Ogilvy; Shrive, Nigel G; Rosvold, Joshua M; Thornton, Gail M; Frank, Cyril B; Hart, David A

    2013-10-01

    Heterotopic mineralization may result in tendon weakness, but effects on other biomechanical responses have not been reported. We used a needle injury, which accelerates spontaneous mineralization of murine Achilles tendons, to test two hypotheses: that injured tendons would demonstrate altered biomechanical responses; and that unilateral injury would accelerate mineralization bilaterally. Mice underwent left hind (LH) injury (I; n = 11) and were euthanized after 20 weeks along with non-injured controls (C; n = 9). All hind limbs were examined by micro computed tomography followed by biomechanical testing (I = 7 and C = 6). No differences were found in the biomechanical responses of injured tendons compared with controls. However, the right hind (RH) tendons contralateral to the LH injury exhibited greater static creep strain and total creep strain compared with those LH tendons (p ≤ 0.045) and RH tendons from controls (p ≤ 0.043). RH limb lesions of injured mice were three times larger compared with controls (p = 0.030). Therefore, despite extensive mineralization, changes to the responses we measured were limited or absent 20 weeks postinjury. These results also suggest that bilateral occurrence should be considered where tendon mineralization is identified clinically. This experimental system may be useful to study the mechanisms of bilateral new bone formation in tendinopathy and other conditions.

  17. Self-monitoring surveillance system for prestressing tendons. Phase I small business innovation research

    SciTech Connect

    Tabatabai, H.

    1995-12-01

    Assured safety and operational reliability of post-tensioned concrete components of nuclear power plants are of great significance to the public, electric utilities, and regulatory agencies. Prestressing tendons provide principal reinforcement for containment and other structures. In this phase of the research effort, the feasibility of developing a passive surveillance system for identification of ruptures in tendon wires was evaluated and verified. The concept offers high potential for greatly increasing effectiveness of presently-utilized periodic tendon condition surveillance programs. A one-tenth scale ring model of the Palo Verde nuclear containment structure was built inside the Structural Laboratory. Dynamic scaling (similitude) relationships were used to relate measured sensor responses recorded during controlled wire breakages to the expected prototype containment tendon response. Strong and recognizable signatures were detected by the accelerometers used. It was concluded that the unbonded prestressing tendons provide an excellent path for transmission of stress waves resulting from wire breaks. Accelerometers placed directly on the bearing plates at the ends of tendons recorded high-intensity waveforms. Accelerometers placed elsewhere on concrete surfaces of the containment model revealed substantial attenuation and reduced intensities of captured waveforms. Locations of wire breaks could be determined accurately through measurement of differences in arrival times of the signal at the sensors. Pattern recognition systems to be utilized in conjunction with the proposed concept will provide a basis for an integrated and automated tool for identification of wire breaks.

  18. 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

  19. Single-stage reconstruction of flexor tendons with vascularized tendon transfers.

    PubMed

    Cavadas, P C; Pérez-García, A; Thione, A; Lorca-García, C

    2015-03-01

    The reconstruction of finger flexor tendons with vascularized flexor digitorum superficialis (FDS) tendon grafts (flaps) based on the ulnar vessels as a single stage is not a popular technique. We reviewed 40 flexor tendon reconstructions (four flexor pollicis longus and 36 finger flexors) with vascularized FDS tendon grafts in 38 consecutive patients. The donor tendons were transferred based on the ulnar vessels as a single-stage procedure (37 pedicled flaps, three free flaps). Four patients required composite tendon and skin island transfer. Minimum follow-up was 12 months, and functional results were evaluated using a total active range of motion score. Multiple linear regression analysis was performed to evaluate the factors that could be associated with the postoperative total active range of motion. The average postoperative total active range of motion (excluding the thumbs) was 178.05° (SD 50°). The total active range of motion was significantly lower for patients who were reconstructed with free flaps and for those who required composite tendon and skin island flap. Age, right or left hand, donor/motor tendon and pulley reconstruction had no linear effect on total active range of motion. Overall results were comparable with a published series on staged tendon grafting but with a lower complication rate. Vascularized pedicled tendon grafts/flaps are useful in the reconstruction of defects of finger flexor tendons in a single stage, although its role in the reconstructive armamentarium remains to be clearly established.

  20. Calcific tendonitis of the tibialis posterior tendon at the navicular attachment

    PubMed Central

    Harries, Luke; Kempson, Susan; Watura, Roland

    2011-01-01

    Calcific tendinosis (tendonosis/tendonitis) is a condition which results from the deposition of calcium hydroxyapatite crystals in any tendon of the body. Calcific tendonitis usually presents with pain, which can be exacerbated by prolonged use of the affected tendon. We report a case of calcific tendinosis in the posterior tibialis tendon at the navicular insertion. The pathology is rare in the foot, and extremely rare in the tibialis posterior tendon, indeed there are only 2 reported in the published literature. This case report highlights the need to consider calcific tendinosis in the foot despite its rarity. If this diagnosis is considered early, appropriate investigations can then be requested and unnecessary biopsies, use of antibiotics and surgery can be avoided. We also discuss possible causes of calcific tendinosis in the tibialis posterior tendon, the role of imaging modalities and review treatment methods. PMID:22470798

  1. The Tendons and Muscles of the Mouse Forelimb during Embryonic Development

    PubMed Central

    Watson, Spencer S.; Riordan, Timothy J.; Pryce, Brian A.; Schweitzer, Ronen

    2009-01-01

    The range and precision of limb movements are dependent on the specific patterns of muscles and tendons. To facilitate analyses of tendon and muscle phenotypes we compiled a description of these tissues in the forelimb of developing mouse embryos. Individual tendons, muscles and ligaments were annotated in a series of transverse sections through the forelimb of an embryo at day 18.5 of embryonic development (E18.5). Transverse sections present a distinctive and highly reproducible pattern of the muscles and tendons at different limb levels that can be used as a simple reference in analyses of mutant phenotypes. A comparable set of sections from an embryo at E14.5 was included to highlight structural features that change during the maturation of the musculoskeletal system. The ability to define the precise position of transverse sections along the proximal-distal axis of the limb may also be useful in studies of other features in developing limbs. PMID:19235726

  2. The immunosuppressive effect of Siglecs on tendon-bone healing after ACL reconstruction.

    PubMed

    Hu, Jiang; Yao, Bin; Yang, Xiao; Ma, Fang

    2015-01-01

    The quality of the bone-tendon healing is very important to the surgery outcome after anterior cruciate ligament reconstruction. The necrosis of autograft and local new blood vessels occur after the surgery. The fibroblasts and mesenchymal cells presenting in the tendon-bone interface as well as the infiltrated of neutrophils and macrophages improve the biomechanical properties of the healing. We hypothesize that immunosuppressive effect of Siglecs which present on the surface of neutrophils and macrophages play the important roles to regulate acute local inflammatory reaction, maintain the physiological environment and induce the differentiation of the pluripotent cells to form the accepted histologic structure healing of the tendon-bone interface. It might be helpful to understand the mechanism of tendon-bone healing.

  3. Duplication of the extensor carpi ulnaris tendon.

    PubMed

    Barfred, T; Adamsen, S

    1986-05-01

    Three cases are presented, in which an anomalous tendon slip between the extensor carpi ulnaris tendon and the extensor apparatus of the fifth finger was found. One of the patients was a violinist, who had serious impairment of the left wrist joint and the small finger due to the anomaly. The symptoms disappeared after excision.

  4. 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.

  5. Temporal features of human tendon vibration illusions.

    PubMed

    Fuentes, Christina T; Gomi, Hiroaki; Haggard, Patrick

    2012-12-01

    Muscle spindles provide information about the position and movement of our bodies. One method for investigating spindle signals is tendon vibration. Vibration of flexor tendons can produce illusions of extension, and vibration of extensor tendons can produce illusions of flexion. Here we estimate the temporal resolution and persistence of these illusions. In Experiments 1 and 2, sequences of alternating vibration of wrist flexor and extensor tendons produced position illusions that varied with alternation period. When vibrations alternated at 1 Hz or slower, perceived position at the end of the sequence depended on the last vibration. When vibrations alternated every 0.3 s, perceived position was independent of the last vibration. Experiment 2 verified and extended these results using more trials and concurrent electromyographic recording. Although tendon vibrations sometimes induce reflexive muscle activity, we found no evidence that such activity contributed to these effects. Experiment 3 investigated how long position sense is retained when not updated by current information from spindles. Our first experiments suggested that vibrating antagonistic tendons simultaneously could produce conflicting inputs, leaving position sense reliant on memory of position prior to vibration onset. We compared variability in position sense after different durations of such double vibration. After 12 s of double vibration, variability across trials exceeded levels predicted from vibrations of flexor or extensor tendons alone. This suggests that position sense memory had decayed too much to substitute for the current conflicting sensory information. Together, our results provide novel, quantitative insight into the temporal properties of tendon vibration illusions.

  6. Tendon Vasculature in Health and Disease

    PubMed Central

    Tempfer, Herbert; Traweger, Andreas

    2015-01-01

    Tendons represent a bradytrophic tissue which is poorly vascularized and, compared to bone or skin, heal poorly. Usually, a vascularized connective scar tissue with inferior functional properties forms at the injury site. Whether the increased vascularization is the root cause of tissue impairments such as loss of collagen fiber orientation, ectopic formation of bone, fat or cartilage, or is a consequence of these pathological changes remains unclear. This review provides an overview of the role of tendon vasculature in healthy and chronically diseased tendon tissue as well as its relevance for tendon repair. Further, the nature and the role of perivascular tendon stem/progenitor cells residing in the vascular niche will be discussed and compared to multipotent stromal cells in other tissues. PMID:26635616

  7. Effects of flunixin meglumine on experimental tendon wound healing: A histopathological and mechanical study in rabbits.

    PubMed

    Behfar, Mehdi; Hobbenaghi, Rahim; Sarrafzadeh-Rezaei, Farshid

    2013-01-01

    Tendons are frequently targets of injury in sports and work. Whether nonsteroidal anti-inflammatory drugs (NSAIDs) have beneficial effects on tendon healing is still a matter of debate. This study was conducted to evaluate effects of flunixin meglumine (FM) on tendon healing after experimentally induced acute trauma. Twenty eight adult male New Zealand White rabbits were subjected to complete transection of deep digital flexor tendons followed by suture placement. Treatment group received intramuscular injection of FM for three days, and controls received placebo. Subsequently, cast immobilization was continued for two weeks. Animals were sacrificed four weeks after surgery and tissue samples were taken. The histological evaluations revealed improved structural characteristics of neotendon formation including fibrillar linearity, fibrillar continuity and neovascularization in treatment group compared to those of controls (p < 0.05). However, no significant differences were found between two groups in terms of epitenon thickness (p > 0.05). Mechanical evaluation revealed significant increase in load-related material properties including ultimate load, yield load, energy absorption and ultimate stress in treatment group compared to those of control group (p < 0.05). However, no statistically significant differences in terms of stiffness and ultimate strain were found (p > 0.05). The present study showed that intramuscular injection of FM resulted in improved structural and mechanical properties of tendon repairs and it could be an effective treatment for acute tendon injuries like severance and laceration.

  8. Morphological study of the Golgi tendon organ in equine superficial digital flexor tendon.

    PubMed

    Watanabe, Takafumi; Hosaka, Yoshinao; Yamamoto, Etsuko; Ueda, Hiromi; Tangkawattana, Prasarn; Takehana, Kazushige

    2004-08-01

    The Golgi tendon organ (GTO) is an encapsulated fusiform mechanoreceptor siding in the musculo-tendinous junction of many animal species. Inhibitory function of afferent nerve fibers distributed from nearby motor units, the organ responds to active tension exerted onto the muscle. The morphological features of the equine GTO have not yet been elucidated. Additionally, there is some controversy regarding to the existence of the GTO in the equine superficial digital flexor tendon (SDFT). Therefore, immunohistochemistry and immunoelectron microscopy using alcian blue (pH 2.5) staining and the silver-enhanced colloidal gold method were carried out to determine both the location and characteristics of the GTO at the musculo-tendinous junction of the SDFT. A GTO with a fusiform structure of approximately 3 mm in length was found in the tendinous part. The lumen of the GTO was divided into compartments by septal cells. Each compartment contained collagen fibrils, nerve fibers and Schwann cells. This is the first report of the equine GTO.

  9. Anterior Cruciate Ligament Reconstruction: Clinical Outcomes of Patella Tendon and Hamstring Tendon Grafts

    PubMed Central

    Gulick, Dawn T.; Yoder, Heather N.

    2002-01-01

    An injury to the ACL can result in significant functional impairment. It has been estimated that more than 100,000 new ACL injuries occur each year. Surgeons employ numerous techniques for reconstruction of the ACL. Of critical importance is the source of the graft to replace the damaged ACL. The graft choices include autografts (the patient's own tissue), allografts (donor tendon), and synthetic/prosthetic ligaments. Tissue harvest sites for autografting include the middle third of the patella tendon, the quadriceps tendon, semitendinosus tendon, gracilis tendon, iliotibial band, tensor fascia lata, and the Achilles tendon. Selection of the type of graft material is predicated upon the tissue's ability to tolerate high levels of stress. Likewise, the clinical presentation and functional outcome is related to the graft material selected. This manuscript specifically examined the patella tendon and hamstring tendon grafts. Numerous manuscripts that studied the outcomes of these graft materials were compiled to help the clinician appreciate the advantages and disadvantages of each of the graft materials. Outcome measures such as thigh circumference, knee range of motion, isokinetic strength, knee stability, pain, and vertical jump/1-leg hop were incorporated. The purpose of this manuscript was to compare and contrast the clinical presentation of patients who underwent an ACL reconstruction using the patella tendon versus the hamstring tendons. This information can be valuable to the clinician when considering the rehabilitation protocol after ACL reconstruction. PMID:24701126

  10. Osmotic pressure induced tensile forces in tendon collagen

    NASA Astrophysics Data System (ADS)

    Masic, Admir; Bertinetti, Luca; Schuetz, Roman; Chang, Shu-Wei; Metzger, Till Hartmut; Buehler, Markus J.; Fratzl, Peter

    2015-01-01

    Water is an important component of collagen in tendons, but its role for the function of this load-carrying protein structure is poorly understood. Here we use a combination of multi-scale experimentation and computation to show that water is an integral part of the collagen molecule, which changes conformation upon water removal. The consequence is a shortening of the molecule that translates into tensile stresses in the range of several to almost 100 MPa, largely surpassing those of about 0.3 MPa generated by contractile muscles. Although a complete drying of collagen would be relevant for technical applications, such as the fabrication of leather or parchment, stresses comparable to muscle contraction already occur at small osmotic pressures common in biological environments. We suggest, therefore, that water-generated tensile stresses may play a role in living collagen-based materials such as tendon or bone.

  11. [Effects of Gravity on Attachment of Tendon to Bone

    NASA Technical Reports Server (NTRS)

    Johnson, Roger B.

    1997-01-01

    We have received and processed all samples for either light or scanning electron microscopic analysis and have completed the histomorphometric analysis. We have characterized the changes caused by spaceflight to tendon attachments to the calcaneus, tibia, fibula and femur and compared them to hindlimbs and forelimbs from NIH.RZ. Soleus muscle histomorphometry has also been completed. Our results suggest severe osteoporosis in the femur, fibula and tibia of animals coincident to spaceflight, which had not resolved after 4-5 days following return to earth. This was evident at all sites, including sites of tendon attachments. This atrophy was not evident in the calcaneus. No muscle atrophy was evident. Comparison of scanning photomicrographs of flight animals with other lactating animals demonstrated structural similarities and suggested that it might be worthwhile to assess whether lactation is a factor in development of the osteoporosis in the spaceflight animals. In addition, evaluation of total calcium utilization by spaceflight animals would be beneficial.

  12. 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.

  13. DYNAMIC SONOGRAPHY OF THE EQUINE METACARPO(TARSO)PHALANGEAL DIGITAL FLEXOR TENDON SHEATH.

    PubMed

    DiGiovanni, Daria L; Rademacher, Nathalie; Riggs, Laura M; Baumruck, Rebecca A; Gaschen, Lorrie

    2016-11-01

    Palmar/plantar annular desmitis is a common disease that may be associated with adhesions and structures affecting the flexor tendons, which requires tenoscopy to diagnose. The purpose of this descriptive study was to develop a dynamic sonographic technique for evaluating the motion of normal equine flexor tendons in relation to the palmar/plantar annular ligament and to compare findings with horses previously diagnosed with palmar/plantar annular desmitis. Ten healthy adult horses were examined prospectively and the images of four horses diagnosed with palmar/plantar annular desmitis were retrospectively evaluated. Dynamic sonography was performed at the level of the metacarpo/metatarsophalangeal joint by maximally extending and flexing the interphalangeal joints. Palmar/plantar annular ligament thickness (mm), size of any gap between the flexor tendons, and subjectively increased angulation of the long linear echoes of the superficial digital flexor tendon were measured. The presence of gliding motion between the palmar/plantar annular ligament and superficial digital flexor tendon was determined by consensus. Twenty-eight healthy control limbs (16 hind/12 fore) and four with palmar/plantar annular desmitis (3 hind/1 fore) were evaluated. Controls had unrestricted gliding motion between the palmar/plantar annular ligament and flexor tendons and zero to 13° of angulation of the long linear echoes. The four affected horses had restricted gliding motion and between 20-35° angulation of the long linear echoes. Dynamic ultrasound is a feasible technique for detecting restricted flexor tendon and palmar/plantar annular ligament gliding motion, as well as subjectively increased angulation of the long linear echoes of the flexor tendon in affected horses compared with controls and warrants further investigation.

  14. The double sheath system and tendon gliding in zone 2C.

    PubMed

    Tang, J B

    1995-06-01

    Anatomical structures, the morphology of gliding tunnel, the gliding amplitude of tendons and the range of finger motion after sheath incision in zone 2C were studied in 40 fingers of ten preserved cadaver hands. The tendon of FDS in zone 2C courses around that of FDP, and FDS serves functionally as a second sheath for FDP. This "double sheath" system in zone 2C accounts for the poor results of tendon repair in zone 2C. The tendon repairs in zone 2C glide into zone 2D during finger flexion. Therefore, the condition of the gliding tunnel of zone 2D is also important to the function of tendon repairs in zone 2C. The range of motion was shown to be insignificantly influenced by partial incision of the A2 pulley, and this did not decrease the total strength of the sheath markedly. These suggest that partial incision or enlargement of the A2 pulley can be carried out for tendon repairs in zone 2C without causing mechanical problems of function.

  15. A Clinical, Biological, and Biomaterials Perspective into Tendon Injuries and Regeneration

    PubMed Central

    Walden, Grace; Liao, Xin; Donell, Simon; Raxworthy, Mike J.; Riley, Graham P.

    2017-01-01

    Tendon injury is common and debilitating, and it is associated with long-term pain and ineffective healing. It is estimated to afflict 25% of the adult population and is often a career-ending disease in athletes and racehorses. Tendon injury is associated with high morbidity, pain, and long-term suffering for the patient. Due to the low cellularity and vascularity of tendon tissue, once damage has occurred, the repair process is slow and inefficient, resulting in mechanically, structurally, and functionally inferior tissue. Current treatment options focus on pain management, often being palliative and temporary and ending in reduced function. Most treatments available do not address the underlying cause of the disease and, as such, are often ineffective with variable results. The need for an advanced therapeutic that addresses the underlying pathology is evident. Tissue engineering and regenerative medicine is an emerging field that is aimed at stimulating the body's own repair system to produce de novo tissue through the use of factors such as cells, proteins, and genes that are delivered by a biomaterial scaffold. Successful tissue engineering strategies for tendon regeneration should be built on a foundation of understanding of the molecular and cellular composition of healthy compared with damaged tendon, and the inherent differences seen in the tissue after disease. This article presents a comprehensive clinical, biological, and biomaterials insight into tendon tissue engineering and regeneration toward more advanced therapeutics. PMID:27596929

  16. A Clinical, Biological, and Biomaterials Perspective into Tendon Injuries and Regeneration.

    PubMed

    Walden, Grace; Liao, Xin; Donell, Simon; Raxworthy, Mike J; Riley, Graham P; Saeed, Aram

    2017-02-01

    Tendon injury is common and debilitating, and it is associated with long-term pain and ineffective healing. It is estimated to afflict 25% of the adult population and is often a career-ending disease in athletes and racehorses. Tendon injury is associated with high morbidity, pain, and long-term suffering for the patient. Due to the low cellularity and vascularity of tendon tissue, once damage has occurred, the repair process is slow and inefficient, resulting in mechanically, structurally, and functionally inferior tissue. Current treatment options focus on pain management, often being palliative and temporary and ending in reduced function. Most treatments available do not address the underlying cause of the disease and, as such, are often ineffective with variable results. The need for an advanced therapeutic that addresses the underlying pathology is evident. Tissue engineering and regenerative medicine is an emerging field that is aimed at stimulating the body's own repair system to produce de novo tissue through the use of factors such as cells, proteins, and genes that are delivered by a biomaterial scaffold. Successful tissue engineering strategies for tendon regeneration should be built on a foundation of understanding of the molecular and cellular composition of healthy compared with damaged tendon, and the inherent differences seen in the tissue after disease. This article presents a comprehensive clinical, biological, and biomaterials insight into tendon tissue engineering and regeneration toward more advanced therapeutics.

  17. Biocompatibility and degradation of tendon-derived scaffolds

    PubMed Central

    Alberti, Kyle A.; Xu, Qiaobing

    2016-01-01

    Decellularized extracellular matrix has often been used as a biomaterial for tissue engineering applications. Its function, once implanted can be crucial to determining whether a tissue engineered construct will be successful, both in terms of how the material breaks down, and how the body reacts to the material’s presence in the first place. Collagen is one of the primary components of extracellular matrix and has been used for a number of biomedical applications. Scaffolds comprised of highly aligned collagen fibrils can be fabricated directly from decellularized tendon using a slicing, stacking, and rolling technique, to create two- and three-dimensional constructs. Here, the degradation characteristics of the material are evaluated in vitro, showing that chemical crosslinking can reduce degradation while maintaining fiber structure. In vivo, non-crosslinked and crosslinked samples are implanted, and their biological response and degradation evaluated through histological sectioning, trichrome staining, and immunohistochemical staining for macrophages. Non-crosslinked samples are rapidly degraded and lose fiber morphology while crosslinked samples retain both macroscopic structure as well as fiber orientation. The cellular response of both materials is also investigated. The in vivo response demonstrates that the decellularized tendon material is biocompatible, biodegradable and can be crosslinked to maintain surface features for extended periods of time in vivo. This study provides material characteristics for the use of decellularized tendon as biomaterial for tissue engineering. PMID:26816651

  18. Electromechanical properties of dried tendon and isoelectrically focused collagen hydrogels.

    PubMed

    Denning, D; Abu-Rub, M T; Zeugolis, D I; Habelitz, S; Pandit, A; Fertala, A; Rodriguez, B J

    2012-08-01

    Assembling artificial collagenous tissues with structural, functional, and mechanical properties which mimic natural tissues is of vital importance for many tissue engineering applications. While the electro-mechanical properties of collagen are thought to play a role in, for example, bone formation and remodeling, this functional property has not been adequately addressed in engineered tissues. Here the electro-mechanical properties of rat tail tendon are compared with those of dried isoelectrically focused collagen hydrogels using piezoresponse force microscopy under ambient conditions. In both the natural tissue and the engineered hydrogel D-periodic type I collagen fibrils are observed, which exhibit shear piezoelectricity. While both tissues also exhibit fibrils with parallel orientations, Fourier transform analysis has revealed that the degree of parallel alignment of the fibrils in the tendon is three times that of the dried hydrogel. The results obtained demonstrate that isoelectrically focused collagen has similar structural and electro-mechanical properties to that of tendon, which is relevant for tissue engineering applications.

  19. Biological Augmentation of Rotator Cuff Tendon Repair

    PubMed Central

    Kovacevic, David

    2008-01-01

    A histologically normal insertion site does not regenerate following rotator cuff tendon-to-bone repair, which is likely due to abnormal or insufficient gene expression and/or cell differentiation at the repair site. Techniques to manipulate the biologic events following tendon repair may improve healing. We used a sheep infraspinatus repair model to evaluate the effect of osteoinductive growth factors and BMP-12 on tendon-to-bone healing. Magnetic resonance imaging and histology showed increased formation of new bone and fibrocartilage at the healing tendon attachment site in the treated animals, and biomechanical testing showed improved load-to-failure. Other techniques with potential to augment repair site biology include use of platelets isolated from autologous blood to deliver growth factors to a tendon repair site. Modalities that improve local vascularity, such as pulsed ultrasound, have the potential to augment rotator cuff healing. Important information about the biology of tendon healing can also be gained from studies of substances that inhibit healing, such as nicotine and antiinflammatory medications. Future approaches may include the use of stem cells and transcription factors to induce formation of the native tendon-bone insertion site after rotator cuff repair surgery. PMID:18264850

  20. Distal biceps tendon injuries: diagnosis and management.

    PubMed

    Ramsey, M L

    1999-01-01

    Rupture of the distal biceps tendon occurs most commonly in the dominant extremity of men between 40 and 60 years of age when an unexpected extension force is applied to the flexed arm. Although previously thought to be an uncommon injury, distal biceps tendon ruptures are being reported with increasing frequency. The rupture typically occurs at the tendon insertion into the radial tuberosity in an area of preexisting tendon degeneration. The diagnosis is made on the basis of a history of a painful, tearing sensation in the antecubital region. Physical examination demonstrates a palpable and visible deformity of the distal biceps muscle belly with weakness in flexion and supination. The ability to palpate the tendon in the antecubital fossa may indicate partial tearing of the biceps tendon. Plain radiographs may show hypertrophic bone formation at the radial tuberosity. Magnetic resonance imaging is generally not required to diagnose a complete rupture but may be useful in the case of a partial rupture. Early surgical reattachment to the radial tuberosity is recommended for optimal results. A modified two-incision technique is the most widely used method of repair, but anterior single-incision techniques may be equally effective provided the radial nerve is protected. The patient with a chronic rupture may benefit from surgical reattachment, but proximal retraction and scarring of the muscle belly can make tendon mobilization difficult, and inadequate length of the distal biceps tendon may necessitate tendon augmentation. Postoperative rehabilitation must emphasize protected return of motion for the first 8 weeks after repair. Formal strengthening may begin as early as 8 weeks, with a return to unrestricted activities, including lifting, by 5 months.

  1. Percutaneous techniques for tendon transfers in the foot and ankle.

    PubMed

    Panchbhavi, Vinod Kumar

    2014-03-01

    Tendon transfer procedures are useful for replacing a dysfunctional or diseased tendon or for restoring muscle imbalance. The tendon to be transferred is harvested as distal as is necessary to provide adequate length for rerouting and attachment at the different site. The harvesting of tendon itself can be attained using an open surgical approach or minimally invasive percutaneous techniques that limit surgical exposure. This article describes percutaneous techniques for tendon transfer procedures used to address foot and ankle disorders.

  2. Tendon injury and tendinopathy: healing and repair.

    PubMed

    Sharma, Pankaj; Maffulli, Nicola

    2005-01-01

    Tendon disorders are frequent and are responsible for substantial morbidity both in sports and in the workplace. Tendinopathy, as opposed to tendinitis or tendinosis, is the best generic descriptive term for the clinical conditions in and around tendons arising from overuse. Tendinopathy is a difficult problem requiring lengthy management, and patients often respond poorly to treatment. Preexisting degeneration has been implicated as a risk factor for acute tendon rupture. Several physical modalities have been developed to treat tendinopathy. There is limited and mixed high-level evidence to support the, albeit common, clinical use of these modalities. Further research and scientific evaluation are required before biological solutions become realistic options.

  3. Fibromatosis of the flexor pollicus longus tendon

    PubMed Central

    Damkat-Thomas, L; Black, CE; Herbert, K

    2010-01-01

    An unusual case of fibromatosis of the dominant left flexor pollicus longus (FPL) in a thirteen year old schoolboy. Initially presenting with pain in the thenar eminence and difficulty flexing the metacarpal phalangeal joint (MPJ), other symptoms include locking, triggering and difficulty writing. MRI showed a 4cm segment of thickened abnormal tendon. Intra-operatively three 1cm nodules were excised from the FPL while preserving the tendon. Histopathology reported the nodules as fibromatosis. A literature search revealed that this has not previously been reported although symptomatic tendon sheath fibromas have. Our patient achieved a good result following surgical intervention and the two year review has shown no complications. PMID:24946359

  4. A review of work on artificial tendons.

    PubMed

    Murray, G A; Semple, J C

    1979-07-01

    Work done to date on artificial tendons by many authors is described in chronological order. A brief description of the techniques and materials is given in each case, with a summary of the results. The overall implications of the work are discussed in terms of prosthesis durability, the attachment to bone and tendon, mechanical properties and the volume of scar tissue generated. It is concluded that construction of a permanent artificial tendon is a realistic and worthwhile aim; further experimental work ought to include long term in vivo testing with means provided for monitoring any drift of the attachment points.

  5. Stem Cells for Augmenting Tendon Repair

    PubMed Central

    Gulotta, Lawrence V.; Chaudhury, Salma; Wiznia, Daniel

    2012-01-01

    Tendon healing is fraught with complications such as reruptures and adhesion formation due to the formation of scar tissue at the injury site as opposed to the regeneration of native tissue. Stem cells are an attractive option in developing cell-based therapies to improve tendon healing. However, several questions remain to be answered before stem cells can be used clinically. Specifically, the type of stem cell, the amount of cells, and the proper combination of growth factors or mechanical stimuli to induce differentiation all remain to be seen. This paper outlines the current literature on the use of stem cells for tendon augmentation. PMID:22190960

  6. Ultrasonic stress measurements in prestressing tendons

    NASA Astrophysics Data System (ADS)

    Washer, Glenn A.; Green, Robert E.

    2002-05-01

    The goal of this research was to examine ultrasonic stress measurement techniques for the condition assessment of prestressing tendons. Acoustoelastic measurements were made in prestressing rods and strands, and constants are reported that relate the change in ultrasonic velocity to the change in stress. The effects of dispersion in prestressing tendons, which act as circular wave guides for ultrasonic waves, were measured and evaluated. For this research, narrow-band, noncontact Electromagnetic Acoustic Transducers (EMATs) were designed to launch and receive ultrasonic waves propagating within the tendons.

  7. Proximal Biceps Tendon and Rotator Cuff Tears.

    PubMed

    Virk, Mandeep S; Cole, Brian J

    2016-01-01

    The long head of biceps tendon (LHBT) is frequently involved in rotator cuff tears and can cause anterior shoulder pain. Tendon hypertrophy, hourglass contracture, delamination, tears, and tendon instability in the bicipital groove are common macroscopic pathologic findings affecting the LHBT in the presence of rotator cuff tears. Failure to address LHBT disorders in the setting of rotator cuff tear can result in persistent shoulder pain and poor satisfaction after rotator cuff repair. Tenotomy or tenodesis of the LHBT are effective options for relieving pain arising from the LHBT in the setting of reparable and selected irreparable rotator cuff tears.

  8. Les plaies du tendon patellaire

    PubMed Central

    Mechchat, Atif; Elidrissi, Mohammed; Mardy, Abdelhak; Elayoubi, Abdelghni; Shimi, Mohammed; Elibrahimi, Abdelhalim; Elmrini, Abdelmajid

    2014-01-01

    Les plaies du tendon patellaire sont peu fréquentes et sont peu rapportés dans la littérature, contrairement aux ruptures sous cutanées. Les sections du tendon patellaire nécessitent une réparation immédiate afin de rétablir l'appareil extenseur et de permettre une récupération fonctionnelle précoce. A travers ce travail rétrospectif sur 13 cas, nous analysons les aspects épidémiologiques, thérapeutiques et pronostiques de ce type de pathologie en comparant différents scores. L’âge moyen est de 25 ans avec une prédominance masculine. Les étiologies sont dominées par les accidents de la voie publique (68%) et les agressions par agent tranchant (26%) et contendant (6 %). Tous nos patients ont bénéficié d'un parage chirurgical avec suture tendineuse direct protégée par un laçage au fils d'aciers en légère flexion. La rééducation est débutée après sédation des phénomènes inflammatoires. Au dernier recul les résultats sont excellents et bon à 92%. Nous n'avons pas noté de différence de force musculaire et d'amplitude articulaire entre le genou sain et le genou lésé. Les lésions ouvertes du tendon patellaire est relativement rare. La prise en charge chirurgicale rapide donne des résultats assez satisfaisants. La réparation est généralement renforcée par un semi-tendineux, synthétique ou métallique en forme de cadre de renfort pour faciliter la réadaptation et réduire le risque de récidive après la fin de l'immobilisation. PMID:25170379

  9. Famotidine suppresses osteogenic differentiation of tendon cells in vitro and pathological calcification of tendon in vivo.

    PubMed

    Yamamoto, Kenichi; Hojo, Hironori; Koshima, Isao; Chung, Ung-il; Ohba, Shinsuke

    2012-12-01

    Heterotopic ossification or calcification follows any type of musculoskeletal trauma and is known to occur after arthroplasties of hip, knee, shoulder, or elbow; fractures; joint dislocations; or tendon ruptures. Histamine receptor H2 (Hrh2) has been shown to be effective for reducing pain and decreasing calcification in patients with calcifying tendinitis, which suggested that H2 blockers were effective for the treatment of tendon ossification or calcification. However, the detailed mechanisms of its action on tendon remain to be clarified. We investigated the mechanisms underlying H2 blocker-mediated suppression of tendon calcification, with a focus on the direct action of the drug on tendon cells. Famotidine treatment suppressed the mRNA expressions of Col10a1 and osteocalcin, ossification markers, in a tendon-derived cell line TT-D6, as well as a preosteoblastic one MC3T3-E1. Both of the cell lines expressed Hrh2; histamine treatment induced osteocalcin expression in these cells. Famotidine administration suppressed calcification in the Achilles tendon of ttw mice, a mouse model of ectopic ossification. These data suggest that famotidine inhibits osteogenic differentiation of tendon cells in vitro, and this inhibition may underlie the anti-calcification effects of the drug in vivo. This study points to the use of H2 blockers as a promising strategy for treating heterotopic ossification or calcification in tendon, and provides evidence in support of the clinical use of famotidine.

  10. 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.

  11. Traumatic tibialis anterior tendon rupture: treatment with a two-stage silicone tube and an interposition hamstring tendons graft protocol.

    PubMed

    Kontogeorgakos, Vasileios; Koutalos, Antonios; Hantes, Michael; Manoudis, Gregory; Badras, Leonidas; Malizos, Konstantinos

    2015-03-01

    A novel technique for managing ruptured tibialis anterior tendon complicated by infection and tendon substance loss in a young adult is described. A two-stage reconstruction technique with a silicon tube and tendon autograft was performed. At first, after local control of the infection, scar excision and placement of a silicone tube was performed. Ten weeks later, ipsilateral hamstrings tendons were harvested and bridged the 7 cm tendon gap. Eighteen months later, the patient has excellent clinical and functional outcome.

  12. The Effect of Corticosteroid on Collagen Expression in Injured Rotator Cuff Tendon

    PubMed Central

    Wei, Anthony S.; Callaci, John J.; Juknelis, Dainius; Marra, Guido; Tonino, Pietro; Freedman, Kevin B.; Wezeman, Frederick H.

    2011-01-01

    Background Subacromial corticosteroid injections are commonly used in the nonoperative management of rotator cuff disease. The effects of corticosteroid injection on injured rotator cuff tendons have not been studied. Our aims were to characterize the acute response of rotator cuff tendons to injury through the analysis of the type-III to type-I collagen expression ratio, a tendon injury marker, and to examine the effects of corticosteroid on this response. Methods Sixty Sprague-Dawley rats were randomly assigned to four groups: control, tendon injury, steroid treatment, and tendon injury and steroid treatment. Six rats served as sham controls. Unilateral tendon injuries were created with full-thickness defects across 50% of the total width of the infraspinatus tendon, 5 mm from its humeral insertion. Steroid treatment with a single dose of methylprednisolone (0.6 mg/kg), equivalent to that given to humans, was injected into the subacromial space under direct visualization. Steroid treatment followed the creation of an injury in the rats in the injury and steroid treatment group. At one, three, and five weeks after the injury, the total RNA isolated from tendons was quantified with real-time polymerase chain reaction with use of primers for type-I and type-III collagen and ribosomal 18s RNA. Results The type-III to type-I collagen expression ratio remained at baseline at all time-points in the control and sham groups. At one week, the type-III to type-I collagen expression ratio increased more than fourfold above the control level in the tendon injury group (p = 0.017) and the tendon injury and steroid treatment group (p = 0.003). The ratio remained greater than twofold above the control at three weeks in both groups (p = 0.003 and p = 0.037) and returned to baseline at five weeks. Interestingly, the group that had steroid treatment only showed an increase of >4.5-fold (p = 0.001) in the type-III to type-I collagen expression ratio, without structural injury to the

  13. Targeted deletion of collagen V in tendons and ligaments results in a classic Ehlers-Danlos syndrome joint phenotype.

    PubMed

    Sun, Mei; Connizzo, Brianne K; Adams, Sheila M; Freedman, Benjamin R; Wenstrup, Richard J; Soslowsky, Louis J; Birk, David E

    2015-05-01

    Collagen V mutations underlie classic Ehlers-Danlos syndrome, and joint hypermobility is an important clinical manifestation. We define the function of collagen V in tendons and ligaments, as well as the role of alterations in collagen V expression in the pathobiology in classic Ehlers-Danlos syndrome. A conditional Col5a1(flox/flox) mouse model was bred with Scleraxis-Cre mice to create a targeted tendon and ligament Col5a1-null mouse model, Col5a1(Δten/Δten). Targeting was specific, resulting in collagen V-null tendons and ligaments. Col5a1(Δten/Δten) mice demonstrated decreased body size, grip weakness, abnormal gait, joint laxity, and early-onset osteoarthritis. These gross changes were associated with abnormal fiber organization, as well as altered collagen fibril structure with increased fibril diameters and decreased fibril number that was more severe in a major joint stabilizing ligament, the anterior cruciate ligament (ACL), than in the flexor digitorum longus tendon. The ACL also had a higher collagen V content than did the flexor digitorum longus tendon. The collagen V-null ACL and flexor digitorum longus tendon both had significant alterations in mechanical properties, with ACL exhibiting more severe changes. The data demonstrate critical differential regulatory roles for collagen V in tendon and ligament structure and function and suggest that collagen V regulatory dysfunction is associated with an abnormal joint phenotype, similar to the hypermobility phenotype in classic Ehlers-Danlos syndrome.

  14. Rupture of the triceps tendon associated with steroid injections.

    PubMed

    Stannard, J P; Bucknell, A L

    1993-01-01

    Rupture of the triceps mechanism is an uncommon injury that has been recognized with increasing frequency in recent years. It has been proposed that such injuries commonly accompany fractures of the radial head and must be actively evaluated in the presence of such a fracture. We present a unique case of isolated rupture of the triceps tendon in an athlete who was lifting weights. This case was complicated by a history of olecranon bursitis that had been treated with numerous local steroid injections, as well as a history of anabolic steroid abuse. Both systemic steroids and local injections may predispose tendons to rupture. Triceps tendon ruptures may result in uniformly good to excellent results if recognized and treated surgically. This case also serves as a reminder of the risks of treating inflamed tissues with local steroid injections, especially in strength athletes who place high demands on their musculoskeletal structures. Finally, this case documents a second case of triceps mechanism rupture in an athlete who has abused anabolic steroids. A study by Hunter et al. suggests that oral steroid abuse may be associated with detrimental effects on the mechanical properties of connective tissue, demonstrating another negative effect of anabolic steroid use in athletes.

  15. Position Control of Tendon-Driven Fingers

    NASA Technical Reports Server (NTRS)

    Abdallah, Muhammad E.; Platt, Robert, Jr.; Hargrave, B.; Pementer, Frank

    2011-01-01

    Conventionally, tendon-driven manipulators implement some force control scheme based on tension feedback. This feedback allows the system to ensure that the tendons are maintained taut with proper levels of tensioning at all times. Occasionally, whether it is due to the lack of tension feedback or the inability to implement sufficiently high stiffnesses, a position control scheme is needed. This work compares three position controllers for tendon-driven manipulators. A new controller is introduced that achieves the best overall performance with regards to speed, accuracy, and transient behavior. To compensate for the lack of tension feedback, the controller nominally maintains the internal tension on the tendons by implementing a two-tier architecture with a range-space constraint. These control laws are validated experimentally on the Robonaut-2 humanoid hand. I

  16. Flexor tendon repair in zone III.

    PubMed

    Al-Qattan, Mohammad M

    2011-01-01

    There is a paucity of the literature on the outcome of zone III flexor tendon injuries. In this paper, we report on the results of zone III flexor tendon repair in 35 consecutive adult patients with clean cut lacerations of both flexor tendons in 42 fingers. There were 25 men and 10 women with an average age of 32 years. Repair of both flexor tendons was performed using 'figure of eight' core sutures and a continuous epitendinous suture. Postoperatively, an immediate active range of motion protocol was applied to ensure full active extension of the interphalangeal joints. The results were assessed using the Strickland-Glogovac grading system. There were no ruptures. One patient with two injured fingers developed complex regional pain syndrome and the final outcome was fair in both fingers. In the remaining 34 patients (40 fingers), 33 patients (38 fingers) had an excellent outcome and the remaining patient (two fingers) had a good outcome.

  17. Glycosaminoglycans in Tendon Physiology, Pathophysiology, and Therapy.

    PubMed

    Ryan, Christina N M; Sorushanova, Anna; Lomas, Alex J; Mullen, Anne Maria; Pandit, Abhay; Zeugolis, Dimitrios I

    2015-07-15

    Although glycosaminoglycans constitute a minor portion of native tissues, they play a crucial role in various physiological processes, while their abnormal expression is associated with numerous pathophysiologies. Glycosaminoglycans have become increasingly prevalent in biomaterial design for tendon repair, given their low immunogenicity and their inherent capacity to stimulate the regenerative processes, while maintaining resident cell phenotype and function. Further, their incorporation into three-dimensional scaffold conformations significantly improves their mechanical properties, while reducing the formation of peritendinous adhesions. Herein, we discuss the role of glycosaminoglycans in tendon physiology and pathophysiology and the advancements achieved to date using glycosaminoglycan-functionalized scaffolds for tendon repair and regeneration. It is evidenced that glycosaminoglycan functionalization has led to many improvements in tendon tissue engineering and it is anticipated to play a pivotal role in future reparative therapies.

  18. Lipoma arborescens of the biceps tendon sheath.

    PubMed

    White, Eric A; Omid, Reza; Matcuk, George R; Domzalski, Jerome T; Fedenko, Alexander N; Gottsegen, Christopher J; Forrester, Deborah M; Patel, Dakshesh B

    2013-10-01

    Lipoma arborescens, described as lipomatous infiltration and distention of synovial villi resulting in a frond-like appearance, most frequently affects the suprapatellar recess of the knee. While there have been reports of this entity involving the upper extremity joints, bursa, and tendon sheaths, we present the first reported case of lipoma arborescens isolated to the biceps tendon sheath. We describe imaging and histologic findings with clinical correlation.

  19. 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.

  20. Tension Distribution in a Tendon-Driven Robotic Finger

    NASA Technical Reports Server (NTRS)

    Abdallah, Muhammad E. (Inventor); Platt, Robert (Inventor); Wampler, II, Charles W. (Inventor)

    2013-01-01

    A method is provided for distributing tension among tendons of a tendon-driven finger in a robotic system, wherein the finger characterized by n degrees of freedom and n+1 tendons. The method includes determining a maximum functional tension and a minimum functional tension of each tendon of the finger, and then using a controller to distribute tension among the tendons, such that each tendon is assigned a tension value less than the maximum functional tension and greater than or equal to the minimum functional tension. The method satisfies the minimum functional tension while minimizing the internal tension in the robotic system, and satisfies the maximum functional tension without introducing a coupled disturbance to the joint torques. A robotic system includes a robot having at least one tendon-driven finger characterized by n degrees of freedom and n+1 tendons, and a controller having an algorithm for controlling the tendons as set forth above.

  1. The cell biology of suturing tendons

    PubMed Central

    Wong, J.K.F.; Alyouha, S.; Kadler, K.E.; Ferguson, M.W.J.; McGrouther, D.A.

    2010-01-01

    Trauma by suturing tendon form areas devoid of cells termed “acellular zones” in the matrix. This study aimed to characterise the cellular insult of suturing and acellular zone formation in mouse tendon. Acellular zone formation was evaluated using single grasping sutures placed using flexor tendons with time lapse cell viability imaging for a period of 12 h. Both tension and injury were required to induce cell death and cell movement in the formation of the acellular zone. DNA fragmentation studies and transmission electron microscopy indicated that cells necrosed. Parallel in vivo studies showed that cell-to-cell contacts were disrupted following grasping by the suture in tensioned tendon. Without tension, cell death was lessened and cell-to-cell contacts remained intact. Quantitative immunohistochemistry and 3D cellular profile mapping of wound healing markers over a one year time course showed that acellular zones arise rapidly and showed no evidence of healing whilst the wound healing response occurred in the surrounding tissues. The acellular zones were also evident in a standard modified “Kessler” clinical repair. In conclusion, the suture repair of injured tendons produces acellular zones, which may potentially cause early tendon failure. PMID:20600895

  2. 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.

  3. Predicting tenocyte expression profiles and average molecular concentrations in Achilles tendon ECM from tissue strain and fiber damage.

    PubMed

    Mehdizadeh, Arash; Gardiner, Bruce S; Lavagnino, Michael; Smith, David W

    2017-03-13

    In this study, we propose a method for quantitative prediction of changes in concentrations of a number of key signaling, structural and effector molecules within the extracellular matrix of tendon. To achieve this, we introduce the notion of elementary cell responses (ECRs). An ECR defines a normal reference secretion profile of a molecule by a tenocyte in response to the tenocyte's local strain. ECRs are then coupled with a model for mechanical damage of tendon collagen fibers at different straining conditions of tendon and then scaled up to the tendon tissue level for comparison with experimental observations. Specifically, our model predicts relative changes in ECM concentrations of transforming growth factor beta, interleukin 1 beta, collagen type I, glycosaminoglycan, matrix metalloproteinase 1 and a disintegrin and metalloproteinase with thrombospondin motifs 5, with respect to tendon straining conditions that are consistent with the observations in the literature. In good agreement with a number of in vivo and in vitro observations, the model provides a logical and parsimonious explanation for how excessive mechanical loading of tendon can lead to under-stimulation of tenocytes and a degenerative tissue profile, which may well have bearing on a better understanding of tendon homeostasis and the origin of some tendinopathies.

  4. Low tendon stiffness and abnormal ultrastructure distinguish classic Ehlers-Danlos syndrome from benign joint hypermobility syndrome in patients.

    PubMed

    Nielsen, Rie Harboe; Couppé, Christian; Jensen, Jacob Kildevang; Olsen, Morten Raun; Heinemeier, Katja Maria; Malfait, Fransiska; Symoens, Sofie; De Paepe, Anne; Schjerling, Peter; Magnusson, Stig Peter; Remvig, Lars; Kjaer, Michael

    2014-11-01

    There is a clinical overlap between classic Ehlers-Danlos syndrome (cEDS) and benign joint hypermobility syndrome (BJHS), with hypermobility as the main symptom. The purpose of this study was to investigate the role of type V collagen mutations and tendon pathology in these 2 syndromes. In patients (cEDS, n=7; BJHS, n=8) and controls (Ctrl, n=8), we measured patellar tendon ultrastructure (transmission electron microscopy), dimensions (magnetic resonance imaging), and biomechanical properties (force and ultrasonographic measurements during a ramped isometric knee extension). Mutation analyses (COL5A1 and COL5A2) were performed in the patients. COL5A1 mutations were found in 3 of 4 of the patients with cEDS. Patellar tendon dimensions were similar between the groups, but large, irregular collagen fibrils were in 4 of 5 patients with cEDS. In the cEDS group, tendon stiffness and Young's modulus were reduced to ∼50% of that in BJHS and Ctrl groups (P<0.05). The nonhypermobile, healthy controls were matched with the patients in age, sex, body weight, and physical activity, to compare outcomes. COL5A1 mutations led to structural tendon pathology and low tendon stiffness in cEDS, explaining the patients' hypermobility, whereas no tendon pathology was found that explained the hypermobility in BJHS.

  5. [Treatment of unrecent patellar tendon tear with semitendinous and gracilis tendons].

    PubMed

    Estrada-Malacón, C A; García-Estrada, G A

    2011-01-01

    The patellar tendon lesion is very important due to the role of this tendon on the conformation of the extensor mechanism of the quadriceps. When the terminal end of this mechanism is injured, the extensor function of the knee is completely lost and thus the functional capability of the involved limb is completely disrupted.

  6. Ultrasound-Based Tendon Micromorphology Predicts Mechanical Characteristics of Degenerated Tendons.

    PubMed

    Kulig, Kornelia; Chang, Yu-Jen; Winiarski, Slawomir; Bashford, Gregory R

    2016-03-01

    The purpose of this study was to explore the relationship between tendon micro-morphology quantified from a sonogram and tendon mechanical characteristics measured in vivo. Nineteen adults (nine with unilateral Achilles tendinosis) participated. A commercial ultrasound scanner was used to capture longitudinal B-mode ultrasound images from the mid-portion of bilateral Achilles tendons and a custom image analysis program was used to analyze the spatial frequency content of manually defined regions of interest; in particular, the average peak spatial frequency of the regions of interest was acquired. In addition, a dynamometer and a motion analysis system indirectly measured the tendon mechanical (stiffness) and material (elastic modulus) properties. The peak spatial frequency correlated with tendon stiffness (r = 0.74, p = 0.02) and elastic modulus (r = 0.65, p = 0.05) in degenerated tendons, but not healthy tendons. This is the first study relating the mechanical characteristics of degenerated human Achilles tendon using a non-invasive micro-morphology analysis approach.

  7. MR Imaging and US of the Wrist Tendons.

    PubMed

    Plotkin, Benjamin; Sampath, Srihari C; Sampath, Srinath C; Motamedi, Kambiz

    2016-10-01

    The tendons of the wrist are commonly symptomatic. They can be injured, infected, or inflamed. Magnetic resonance imaging and ultrasonography are useful tools for evaluating the wrist. Pathologic conditions of the wrist tendons include de Quervain tenosynovitis, extensor carpi ulnaris tendinopathy, rheumatoid tenosynovitis, infectious synovitis, tendon tears, hydroxyapatite deposition disease, intersection syndrome, tenosynovial giant cell tumor, and fibroma of the tendon sheath. In this article, we review the normal appearance of the wrist tendons, discuss relevant anatomy, and give an overview of common pathologic conditions affecting the wrist tendons. Online supplemental material is available for this article. (©)RSNA, 2016.

  8. Acute partial rupture of the common extensor tendon.

    PubMed

    Kachrimanis, G; Papadopoulou, O

    2010-06-01

    Rupture of the common extensor tendon is the most common acute tendon injury of the elbow. The authors describe a case of a patient with a clinical history of tendinopathy caused by functional overload of the common extensor tendon, treated also with infiltrations of steroids, and subsequent partial rupture of the tendon during sport activity. The diagnosis was made clinically and at ultrasound (US) examination; US follow-up after some time showed the healing of the lesion. This case confirms that injections of steroids may be a contributory cause of tendon rupture, and emphasizes the sensitivity and specificity of US in the study of pathologies of the elbow tendons.

  9. Direct E-jet printing of three-dimensional fibrous scaffold for tendon tissue engineering.

    PubMed

    Wu, Yang; Wang, Zuyong; Ying Hsi Fuh, Jerry; San Wong, Yoke; Wang, Wilson; San Thian, Eng

    2017-04-01

    Tissue engineering (TE) offers a promising strategy to restore diseased tendon tissue. However, a suitable scaffold for tendon TE has not been achieved with current fabrication techniques. Herein, we report the development of a novel electrohydrodynamic jet printing (E-jetting) for engineering 3D tendon scaffold with high porosity and orientated micrometer-size fibers. The E-jetted scaffold comprised tubular multilayered micrometer-size fibrous bundles, with interconnected spacing and geometric anisotropy along the longitudinal direction of the scaffold. Fiber diameter, stacking pattern, and interfiber distance have been observed to affect the structural stability of the scaffold, of which the enhanced mechanical strength can be obtained for scaffolds with thick fibers as the supporting layer. Human tenocytes showed a significant increase in cellular metabolism on the E-jetted scaffolds as compared to that on conventional electrospun scaffolds (2.7-, 2.8-, and 3.1-fold increase for 150, 300, and 600 µm interfiber distance, respectively; p < 0.05). Furthermore, the scaffolds provided structural support for human tenocytes to align with controlled orientation along the longitudinal direction of the scaffold, and promoted the expression of collagen type I. For the first time, E-jetting has been explored as a novel scaffolding approach for tendon TE, and offers a 3D fibrous scaffold to promote organized tissue reconstruction for potential tendon healing. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 616-627, 2017.

  10. Novel Model of Tendon Regeneration Reveals Distinct Cell Mechanisms Underlying Regenerative and Fibrotic Tendon Healing

    PubMed Central

    Howell, Kristen; Chien, Chun; Bell, Rebecca; Laudier, Damien; Tufa, Sara F.; Keene, Douglas R.; Andarawis-Puri, Nelly; Huang, Alice H.

    2017-01-01

    To date, the cell and molecular mechanisms regulating tendon healing are poorly understood. Here, we establish a novel model of tendon regeneration using neonatal mice and show that neonates heal via formation of a ‘neo-tendon’ that differentiates along the tendon specific lineage with functional restoration of gait and mechanical properties. In contrast, adults heal via fibrovascular scar, aberrant differentiation toward cartilage and bone, with persistently impaired function. Lineage tracing identified intrinsic recruitment of Scx-lineage cells as a key cellular mechanism of neonatal healing that is absent in adults. Instead, adult Scx-lineage tenocytes are not recruited into the defect but transdifferentiate into ectopic cartilage; in the absence of tenogenic cells, extrinsic αSMA-expressing cells persist to form a permanent scar. Collectively, these results establish an exciting model of tendon regeneration and uncover a novel cellular mechanism underlying regenerative vs non-regenerative tendon healing. PMID:28332620

  11. Lower Robotic Arm Assembly Having a Plurality of Tendon Driven Digits

    NASA Technical Reports Server (NTRS)

    Guo, Raymond (Inventor); Bridgwater, Lyndon (Inventor); Nguyen, Vienny (Inventor); Radford, Nicolaus A. (Inventor)

    2016-01-01

    A lower robotic arm includes a base structure, a plurality of digits, and a plurality of tendons. The digits each include first, second, third, and fourth phalanges. Each digit is operatively attached to the base structure at the respective first phalange. A first joint operatively connects the first and second phalange to define a first axis, a second operatively connects the second and third phalange to define a second axis, and a third joint operatively connects the third and fourth phalange to define a third axis, such that the phalanges are selectively rotatable relative to the adjacent phalange, about the respective axis. The tendons are operatively connected to a respective one of the fourth phalanges. Each tendon selectively applies a first torque to the respective fourth phalange to urge the respective phalanges to rotate in a first direction about the respective axes.

  12. Abnormalities of the long head of the biceps tendon of the shoulder: MR imaging findings.

    PubMed

    Tuckman, G A

    1994-11-01

    The normal anatomy of the long head of the biceps tendon of the shoulder has been described in detail [1]. Descriptions of different pathologic processes affecting this structure also have been published [1-3] but have been incomplete, showing only a limited variety of abnormalities. In this article, abnormalities of the long head of the biceps tendon seen on MR images are illustrated in greater variety and detail. Recognizing abnormalities of the biceps tendon is important because they are a common source of shoulder pain both alone and in combination with abnormalities of the rotator cuff, labrum, and other structures. Because incomplete diagnosis can lead to treatment failure, it is important to recognize less common imaging manifestations of common entities.

  13. Reduction in tendon elasticity from unloading is unrelated to its hypertrophy.

    PubMed

    Kinugasa, Ryuta; Hodgson, John A; Edgerton, V Reggie; Shin, David D; Sinha, Shantanu

    2010-09-01

    Tendinous tissues respond to chronic unloading with adaptive changes in mechanical, elastic, and morphological properties. However, little is known about the changes in the detailed structures of the entire tendinous tissue and whether the change in tendon stiffness is related to morphology. We investigated changes in dimensional (volume, cross-sectional area, segmented lengths) and elastic (Young's modulus) properties of the Achilles tendon and distal aponeurosis in response to chronic unilateral lower limb suspension (ULLS) using velocity encoded phase contrast (VE-PC) and three-dimensional morphometric magnetic resonance imaging (MRI). Five healthy subjects underwent ULLS for 4 wk. Axial morphometric MRI was acquired along the entire length from the calcaneous to the medial gastrocnemius insertion. An oblique sagittal VE-PC MRI was also acquired. The Young's modulus could be calculated from this cine dynamic sequence of velocity encoded images from the slope of the stress-strain curve during the submaximal isometric plantar flexion. After 4 wk of ULLS, we found significant (46.7%) decrease in maximum plantar flexion torque. The total volumes of entire tendinous tissue (determined as the sum of the Achilles tendon and distal aponeurosis) increased significantly by 6.4% (11.9 vs. 12.7 ml) after ULLS. In contrast, Young's modulus decreased significantly by 10.4% (211.7 vs. 189.6 MPa) for the Achilles tendon and 29.0% for the distal aponeurosis (158.8 vs. 113.0 MPa) following ULLS. There was no significant correlation between relative change in volume and Young's modulus with 4 wk of ULLS. It is suggested that, although tendon hypertrophy can be expected to adversely affect tendon stiffness, the absence of any significant correlation between the magnitude of tendon hypertrophy and reduced Young's modulus indicates that dimensional factors were not critical to the elastic properties.

  14. Extensor-tendons reconstruction using autogenous palmaris longus tendon grafting for rheumatoid arthritis patients

    PubMed Central

    Chu, Po-Jung; Lee, Hung-Maan; Hou, Yao-Tung; Hung, Sheng-Tsai; Chen, Jung-Kuei; Shih, Jui-Tien

    2008-01-01

    Background The purpose of the study is to retrospectively review the clinical outcome of our study population of middle-aged RA patients who had suffered extensor-tendon rupture. We reported the outcome of autogenous palmaris tendon grafting of multiple extensor tendons at wrist level in 14 middle-aged rheumatoid patients. Methods Between Feb. 2000 to Feb. 2004, thirty-six ruptured wrist level extensor tendons were reconstructed in fourteen rheumatoid patients (11 women and three men) using autogenous palmaris longus tendon as a free interposition graft. In each case, the evaluation was based on both subjective and objective criteria, including the range of MCP joint flexion after surgery, the extension lag at the metacarpophalangeal joint before and after surgery, and the ability of the patient to work. Results and Discussion The average of follow-up was 54.1 months (range, 40 to 72 months). The average range of MCP joint flexion after reconstruction was 66°. The extension lag at the metacarpophalangeal joint significantly improved from a preoperative mean of 38° (range, 25°–60°) to a postoperative mean of 16° (range, 0°–30°). Subjectively all patients were satisfied with the clinical results, and achieved a return to their level of ability before tendon rupture. We found good functional results in our series of interposition grafting using palmaris longus to reconstruct extensor tendon defects in the rheumatoid patients. Conclusion Reconstruction for multiple tendon ruptures is a salvage procedure that is often associated with extensor lag and impairment of overall function. Early aggressive treatment of extensor tendon reconstruction using autogenous palmaris longus tendon as a free interposition graft in the rheumatoid wrist is another viable option to achieve good clinical functional result. PMID:18435845

  15. Elastographic characteristics of the metacarpal tendons in horses without clinical evidence of tendon injury.

    PubMed

    Lustgarten, Meghann; Redding, W Rich; Labens, Raphael; Morgan, Michel; Davis, Weston; Seiler, Gabriela S

    2014-01-01

    Tendon and ligament injuries are common causes of impaired performance in equine athletes. Gray-scale ultrasonography is the current standard method for diagnosing and monitoring these injuries, however this modality only provides morphologic information. Elastography is an ultrasound technique that allows detection and measurement of tissue strain, and may provide valuable mechanical information about equine tendon and ligament injuries. The purpose of this study was to determine the feasibility, reproducibility, and repeatability of elastography; and to describe elastographic characteristics of metacarpal tendons in sound horses. Nineteen legs for 17 clinically sound horses without evidence of musculoskeletal pathology were included. Elastographic images of the superficial and deep digital flexor tendons and the branches of the suspensory ligament (tendon of the interosseous muscle) were described quantitatively and qualitatively. There was no statistically significant difference between operators (P = 0.86) nor within operators (P = 0.93). For qualitative assessments, reproducibility (0.46) was moderate and repeatability (0.78) was good. Similar to human Achilles tendons, equine tendons were classified as predominantly hard using elastography. There was no statistically significant difference in stiffness of the flexor tendons (P = 0.96). No significant difference in stiffness was found with altered leg position during standing (P = 0.84) and while nonweight bearing (P = 0.61). The flexor tendons were softer when imaged in longitudinal versus transverse planes (P < 0.01) however, the suspensory branches were not (P = 0.67). Findings supported future clinical application of elastography as a noninvasive "stall-side" imaging modality for evaluation of the tendons and ligaments of the distal forelimb in horses.

  16. Advanced glycation end-products diminish tendon collagen fiber sliding.

    PubMed

    Li, Yufei; Fessel, Gion; Georgiadis, Marios; Snedeker, Jess G

    2013-04-24

    Connective tissue aging and diabetes related comorbidity are associated with compromised tissue function, increased susceptibility to injury, and reduced healing capacity. This has been partly attributed to collagen cross-linking by advanced glycation end-products (AGEs) that accumulate with both age and disease. While such cross-links are believed to alter the physical properties of collagen structures and tissue behavior, existing data relating AGEs to tendon mechanics is contradictory. In this study, we utilized a rat tail tendon model to quantify the micro-mechanical repercussion of AGEs at the collagen fiber-level. Individual tendon fascicles were incubated with methylglyoxal (MGO), a naturally occurring metabolite known to form AGEs. After incubation in MGO solution or buffer only, tendons were stretched on the stage of a multiphoton confocal microscope and individual collagen fiber stretch and relative fiber sliding were quantified. Treatment by MGO yielded increased fluorescence and elevated denaturation temperatures as found in normally aged tissue, confirming formation of AGEs and related cross-links. No apparent ultrastructural changes were noted in transmission electron micrographs of cross-linked fibrils. MGO treatment strongly reduced tissue stress relaxation (p<0.01), with concomitantly increased tissue yield stress (p<0.01) and ultimate failure stress (p=0.036). MGO did not affect tangential modulus in the linear part of the stress-strain curve (p=0.46). Microscopic analysis of collagen fiber kinematics yielded striking results, with MGO treatment drastically reducing fiber-sliding (p<0.01) with a compensatory increase in fiber-stretch (p<0.01). We thus conclude that the main mechanical effect of AGEs is a loss of tissue viscoelasticity driven by matrix-level loss of fiber-fiber sliding. This has potentially important implications to tissue damage accumulation, mechanically regulated cell signaling, and matrix remodeling. It further highlights the

  17. Specialization of tendon mechanical properties results from interfascicular differences

    PubMed Central

    Thorpe, Chavaunne T.; Udeze, Chineye P.; Birch, Helen L.; Clegg, Peter D.; Screen, Hazel R. C.

    2012-01-01

    Tendons transfer force from muscle to bone. Specific tendons, including the equine superficial digital flexor tendon (SDFT), also store and return energy. For efficient function, energy-storing tendons need to be more extensible than positional tendons such as the common digital extensor tendon (CDET), and when tested in vitro have a lower modulus and failure stress, but a higher failure strain. It is not known how differences in matrix organization contribute to distinct mechanical properties in functionally different tendons. We investigated the properties of whole tendons, tendon fascicles and the fascicular interface in the high-strain energy-storing SDFT and low-strain positional CDET. Fascicles failed at lower stresses and strains than tendons. The SDFT was more extensible than the CDET, but SDFT fascicles failed at lower strains than CDET fascicles, resulting in large differences between tendon and fascicle failure strain in the SDFT. At physiological loads, the stiffness at the fascicular interface was lower in the SDFT samples, enabling a greater fascicle sliding that could account for differences in tendon and fascicle failure strain. Sliding between fascicles prior to fascicle extension in the SDFT may allow the large extensions required in energy-storing tendons while protecting fascicles from damage. PMID:22764132

  18. M1 and M2 macrophage recruitment during tendon regeneration induced by amniotic epithelial cell allotransplantation in ovine.

    PubMed

    Mauro, Annunziata; Russo, Valentina; Di Marcantonio, Lisa; Berardinelli, Paolo; Martelli, Alessandra; Muttini, Aurelio; Mattioli, Mauro; Barboni, Barbara

    2016-04-01

    Recently, we have demonstrated that ovine amniotic epithelial cells (oAECs) allotransplanted into experimentally induced tendon lesions are able to stimulate tissue regeneration also by reducing leukocyte infiltration. Amongst leukocytes, macrophages (Mφ) M1 and M2 phenotype cells are known to mediate inflammatory and repairing processes, respectively. In this research it was investigated if, during tendon regeneration induced by AECs allotransplantation, M1Mφ and M2Mφ phenotype cells are recruited and differently distributed within the lesion site. Ovine AECs treated and untreated (Ctr) tendons were explanted at 7, 14, and 28 days and tissue microarchitecture was analyzed together with the distribution and quantification of leukocytes (CD45 positive), Mφ (CD68 pan positive), and M1Mφ (CD86, and IL12b) and M2Mφ (CD206, YM1 and IL10) phenotype related markers. In oAEC transplanted tendons CD45 and CD68 positive cells were always reduced in the lesion site. At day 14, oAEC treated tendons began to recover their microarchitecture, contextually a reduction of M1Mφ markers, mainly distributed close to oAECs, and an increase of M2Mφ markers was evidenced. CD206 positive cells were distributed near the regenerating areas. At day 28 oAECs treated tendons acquired a healthy-like structure with a reduction of M2Mφ. Differently, Ctr tendons maintained a disorganized morphology throughout the experimental time and constantly showed high values of M1Mφ markers. These findings indicate that M2Mφ recruitment could be correlated to tendon regeneration induced by oAECs allotransplantation. Moreover, these results demonstrate oAECs immunomodulatory role also in vivo and support novel insights into their allogeneic use underlying the resolution of tendon fibrosis.

  19. [The Achilles tendon in sports].

    PubMed

    Segesser, B; Goesele, A; Renggli, P

    1995-06-01

    Achillodynia is a generic term for various types of ailments in the region of the Achilles tendon. For adequate therapy a specific diagnosis is absolutely necessary. Besides an accurate anamnesis and the right choice of terrain and shoes, as well as a clinical examination where one has to specifically keep an eye on muscular imbalance between the gastrocnemius and the soleus muscle and disorders of the ligamentous control of the calcaneus caused by fibular ligament instabilities, a procedure such as radiology, ultrasound, and MR imaging is inevitable. From the differential diagnosis point of view a distinction between peritendinitis, mechanically triggered bursitis (calcaneal and subachilles), bony alterations of the calcaneus (calcaneus spur, Haglund exostosis persistent nucleus of the apophysis, fatigue fracture, etc) and a partial or total rupture (a one-time occurrence or multiple occurrences) has to be made. Occasionally, entrapment of the ramus calcaneus of the sural nerve causes calcaneal pain. If clinically not confirmed, lumbar pain ought to be taken into consideration (discopathy, Bechterew disease, etc). Metabolic disorders (especially uric acid) and underlying rheumatic diseases must be excluded. The therapy of achillodynia includes local and peroral antiphlogistic medication as a concomitant measure. More important is the causal influence of etiological factors, i.e., the correction of muscular imbalance, ensuring control of the calcaneus through bandages and adjustment of sport shoes, changes in training buildup and exercise intensity, just to mention a few. If necessary, surgically splitting the peritendineum, sanitation of a partial rupture, bursectomy and removal of mechanically obstructive exostosis must be done.

  20. Region-specific tendon properties and patellar tendinopathy: a wider understanding.

    PubMed

    Pearson, Stephen John; Hussain, Syed Robiul

    2014-08-01

    Patellar tendinopathy is a common painful musculoskeletal disorder with a very high prevalence in the athletic population that can severely limit or even end an athletic career. To date, the underlying pathophysiology leading to the condition remains poorly understood, although reports suggesting that patellar tendinopathy most frequently concerns the proximal posterior region of the tendon has prompted some researchers to examine region-specific tendon properties for a better understanding of the etiology and potential risk factors associated with the condition. However, to date, research concerning the in vivo region-specific tendon properties in relation to patellar tendinopathy is very scarce, perhaps due to the lack of validated techniques that can determine such properties in vivo. In recent years, a technique has been developed involving an automated tendon-tracking program that appears to be very useful in the determination of region-specific tendon properties in vivo. In terms of regional variations in tendon properties, previous research has demonstrated differences in structural, mechanical, and biochemical properties between the discrete regions of the patellar tendon, but the extent to which these regional variations contribute to patellar tendinopathy remains elusive. In addition, with respect to treatment strategies for patellar tendinopathy, previous research has utilized a wide range of interventions, but the use of eccentric exercise (EE) and/or heavy-slow resistance (HSR) training appear to be most promising. However, the optimal program design variables of EE and HSR training that induce the most favorable effects are yet to be determined. This review article provides a detailed discussion of all of the above to allow a better understanding of the etiology and potential risk factors associated with the condition as well as the most effective treatment strategies. First, a comprehensive literature review is provided with respect to region

  1. After rotator cuff tears, the remaining (intact) tendons are mechanically altered.

    PubMed

    Perry, Stephanie M; Getz, Charles L; Soslowsky, Louis J

    2009-01-01

    Although presumed, damage in the remaining (intact) rotator cuff tendons in the presence of an isolated supraspinatus tendon tear or multiple tendon tear has not been well studied. This study used an animal model of multiple rotator cuff tendon tears to investigate alterations in the remaining (intact) tendon mechanical properties at 4 and 8 weeks after injury. Twenty-four rats served as uninjured controls, whereas 72 were divided among 3 tendon detachment groups: supraspinatus tendon detachment, supraspinatus + infraspinatus tendon detachment, and supraspinatus + subscapularis tendon detachment. The remaining (intact) rotator cuff tendons had decreased mechanical properties in the presence of rotator cuff tears. The remaining (intact) subscapularis and infraspinatus tendon cross-sectional areas increased, whereas tendon modulus decreased after tears of both 1 and 2 tendons. The remaining (intact) tendon cross-sectional areas continued to increase with time after injury. These alterations could potentially lead to further tendon damage and tear progression.

  2. Robot Arm with Tendon Connector Plate and Linear Actuator

    NASA Technical Reports Server (NTRS)

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

  3. Nutritional research may be useful in treating tendon injuries.

    PubMed

    Curtis, Luke

    2016-06-01

    Tendon injures cause a great deal of disability and pain, and increase medical costs. However, relatively little is known about tendon biology and healing. Many tendon-related surgical procedures are not very successful and leave the patient with essentially a chronic injury. New therapeutic approaches for tendon injury are needed. Preliminary evidence suggests that various nutrients such as proteins, amino acids (leucine, arginine, glutamine), vitamins C and D, manganese, copper, zinc, and phytochemicals may be useful in improving tendon growth and healing. More research on nutrition and tendon health is needed. Because many nutrients are required for tendon health, nutritional interventions involving multiple nutrients may be more effective than single-nutrient strategies. In the future, ideal treatment regimens for tendon injuries may include a multifaceted "bundle" of nutrition, drugs, biologic products, extracellular matrix therapies, exercise/physical therapy, and possibly surgery.

  4. The use of nanotechnology in tendon regeneration and repair.

    PubMed

    Oragui, Emeka; Sachinis, Nick; Hope, Natalie; Khan, Wasim S; Adesida, Adetola

    2012-01-01

    Tendon injuries are common and due to their limited capacity for self-healing, the biomechanical and functional properties of healed tendon are usually inferior to normal tissue. Tissue engineering offers the hope of regenerating tendon tissue with the same biomechanical properties of the native undamaged tissue by augmenting the regenerative process of in vivo tissue or producing a functional tissue in vitro that can be implanted into the defective tendon site. Current research on tendon tissue engineering has focused on the role of stem cell and tendon derived cell therapy, scaffolds, chemical and physical stimulation and gene-therapeutic approaches. In this review we review the important functional anatomy and pathomechanics of tendon injury and discuss the current advances in tendon tissue engineering.

  5. No Telescoping Effect with Dual Tendon Vibration

    PubMed Central

    Bellan, Valeria; Wallwork, Sarah B.; Stanton, Tasha R.; Reverberi, Carlo; Gallace, Alberto; Moseley, G. Lorimer

    2016-01-01

    The tendon vibration illusion has been extensively used to manipulate the perceived position of one’s own body part. However, findings from previous research do not seem conclusive sregarding the perceptual effect of the concurrent stimulation of both agonist and antagonist tendons over one joint. On the basis of recent data, it has been suggested that this paired stimulation generates an inconsistent signal about the limb position, which leads to a perceived shrinkage of the limb. However, this interesting effect has never been replicated. The aim of the present study was to clarify the effect of a simultaneous and equal vibration of the biceps and triceps tendons on the perceived location of the hand. Experiment 1 replicated and extended the previous findings. We compared a dual tendon stimulation condition with single tendon stimulation conditions and with a control condition (no vibration) on both ‘upward-downward’ and ‘towards-away from the elbow’ planes. Our results show a mislocalisation towards the elbow of the position of the vibrated arm during dual vibration, in line with previous results; however, this did not clarify whether the effect was due to arm representation contraction (i.e., a ‘telescoping’ effect). Therefore, in Experiment 2 we investigated explicitly and implicitly the perceived arm length during the same conditions. Our results clearly suggest that in all the vibration conditions there was a mislocalisation of the entire arm (including the elbow), but no evidence of a contraction of the perceived arm length. PMID:27305112

  6. Repeated subrupture overload causes progression of nanoscaled discrete plasticity damage in tendon collagen fibrils.

    PubMed

    Veres, Samuel P; Harrison, Julia M; Lee, J Michael

    2013-05-01

    A critical feature of tendons and ligaments is their ability to resist rupture when overloaded, resulting in strains or sprains instead of ruptures. To treat these injuries more effectively, it is necessary to understand how overload affects the primary load-bearing elements of these tissues: collagen fibrils. We have investigated how repeated subrupture overload alters the collagen of tendons at the nanoscale. Using scanning electron microscopy to examine fibril morphology and hydrothermal isometric tension testing to look at molecular stability, we demonstrated that tendon collagen undergoes a progressive cascade of discrete plasticity damage when repeatedly overloaded. With successive overload cycles, fibrils develop an increasing number of kinks along their length. These kinks-discrete zones of plastic deformation known to contain denatured collagen molecules-are accompanied by a progressive and eventual total loss of D-banding along the surface of fibrils, indicating a loss of native molecular packing and further molecular denaturation. Thermal analysis of molecular stability showed that the destabilization of collagen molecules within fibrils is strongly related to the amount of strain energy dissipated by the tendon after yielding during tensile overload. These novel findings raise new questions about load transmission within tendons and their fibrils and about the interplay between crosslinking, strain-energy dissipation ability, and molecular denaturation within these structures.

  7. Effect of muscle fatigue on the compliance of the gastrocnemius medialis tendon and aponeurosis.

    PubMed

    Mademli, Lida; Arampatzis, Adamantios; Walsh, Mark

    2006-01-01

    The aim of the present study was to examine whether or not the compliance of the gastrocnemius medialis (GM) tendon and aponeurosis is influenced by submaximal fatiguing efforts. Fourteen elderly male subjects performed isometric maximal voluntary plantarflexion contractions (MVC) on a dynamometer before and after two fatiguing protocols. The protocols consisted of: (1) submaximal concentric isokinetic contractions (70% isokinetic MVC) at 60 degrees /s and (2) a sustained isometric contraction (40% isometric MVC) until failure to hold the defined moment. Ultrasonography was used to determine the elongation and strain of the GM tendon and aponeurosis. To account for the axis misalignment between ankle and dynamometer, the kinematics of the leg were captured at 120 Hz. The maximum moment decreased from 85.9+/-17.9 Nm prior fatigue to 79.2+/-19 Nm after isokinetic fatigue and to 69.9+/-16.4 Nm after isometric fatigue. The maximal strain of the GM tendon and aponeurosis before fatigue, after isokinetic and after isometric fatigue were 4.9+/-1.1%, 4.4+/-1.1% and 4.3+/-1.1% respectively. Neither the strain nor the elongation showed significant differences before and after each fatiguing task at any 100 N step of the calculated tendon force. This implies that the compliance was not altered after either the isokinetic or the isometric fatiguing task. Therefore it was concluded that the strains during the performed submaximal fatiguing tasks, were too small to provoke any structural changes in tendon and aponeurosis.

  8. The effect of screw insertion torque on tendons fixed with spiked washers.

    PubMed

    Beynnon, B D; Meriam, C M; Ryder, S H; Fleming, B C; Johnson, R J

    1998-01-01

    The long-term success of a hamstring tendon graft depends not only on the type of device that is used for fixation but also on the mechanical interlocking of the soft tissue between the fixation device and bone. The purpose of this study was to evaluate the effect of screw insertion torque on the structural properties of soft tissue fixed to bone with a spiked metal washer. Two bovine tendons, one similar in size to a human semitendinosus tendon and the other similar in size to a human gracilis tendon, were secured to a bovine femur using a figure-of-8 technique with screws and metal spiked washers. A single load to failure was applied at 25 mm/sec. A significant positive linear correlation was observed between fixation screw insertion torque magnitude and the ultimate failure load value. An increase in the fixation screw insertion torque produced an increase in the ultimate failure load value. Similarly, there was a significant positive linear correlation between fixation screw insertion torque magnitude and the average maximum linear load value. No relationship was detected between screw insertion torque magnitude and the linear stiffness values of the tendon-fixation construct, indicating that a reproducible model was used. This study demonstrates that screw insertion torque is an important variable that controls the initial strength of soft tissue fixation to bone.

  9. An experimental 10-meter space truss with tendon control

    NASA Astrophysics Data System (ADS)

    Larson, L. B.; Gergely, P.; Lu, J.; Thorp, J. S.; Aubert, B. H.; Abel, J. F.

    A 10-meter, three-dimensional truss with a rectangular cross section has been constructed for experiments on active control and control-structure interaction. The initial testing of this truss has entailed a single active tendon control of weak-axis dynamic response. Distributed control is achieved by a variably eccentric cable spanning the full length of the structure on each side; the cable tension is adjusted by a linear motor at the root of the vertical cantilever. A set of globally optimal actuator eccentricities have been identified from the feasible set by dynamical programming with the objective of enhancing the damping of the dominant modes while maintaining robustness against feasible structural imperfections. For practical reasons, a slightly modified, near-optimal set of eccentricities has actually been implemented. The eccentric tendon active control scheme has provided stable and effective active damping in the range of 5 percent of critical for random lateral disturbances applied symmetrically in the weak direction at the free end of the truss. The uncontrolled structure has an inherent damping of about 0.5 percent of critical.

  10. 21 CFR 888.3025 - Passive tendon prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) Identification. A passive tendon prosthesis is a device intended to be implanted made of silicon elastomer or a... flexor tendon of the hand. The device is implanted for a period of 2 to 6 months to aid growth of a new tendon sheath. The device is not intended as a permanent implant nor to function as a replacement for...

  11. Tibialis posterior tendon rupture: a cause of rheumatoid flat foot.

    PubMed

    Downey, D J; Simkin, P A; Mack, L A; Richardson, M L; Kilcoyne, R F; Hansen, S T

    1988-03-01

    Flat foot, a major cause of foot pain and disability, may result from rupture of the tibialis posterior tendon. We describe 2 patients with rheumatoid arthritis who developed flat feet secondary to surgically confirmed tendon rupture, and we discuss the anatomy and diagnosis of this condition. In the second patient, we also present the results of tendon imaging with both magnetic resonance and ultrasound.

  12. 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

  13. Multiscale Poly-(ϵ-caprolactone) Scaffold Mimicking Nonlinearity in Tendon Tissue Mechanics

    PubMed Central

    Banik, Brittany L.; Lewis, Gregory S.; Brown, Justin L.

    2016-01-01

    Regenerative medicine plays a critical role in the future of medicine. However, challenges remain to balance stem cells, biomaterial scaffolds, and biochemical factors to create successful and effective scaffold designs. This project analyzes scaffold architecture with respect to mechanical capability and preliminary mesenchymal stem cell response for tendon regeneration. An electrospun fiber scaffold with tailorable properties based on a “Chinese-fingertrap” design is presented. The unique criss-crossed fiber structures demonstrate non-linear mechanical response similar to that observed in native tendon. Mechanical testing revealed that optimizing the fiber orientation resulted in the characteristic “S”-shaped curve, demonstrating a toe region and linear elastic region. This project has promising research potential across various disciplines: vascular engineering, nerve regeneration, and ligament and tendon tissue engineering. PMID:27141530

  14. Development of high shrinkage polyethylene terephthalate (PET) shape memory polymer tendons for concrete crack closure

    NASA Astrophysics Data System (ADS)

    Teall, Oliver; Pilegis, Martins; Sweeney, John; Gough, Tim; Thompson, Glen; Jefferson, Anthony; Lark, Robert; Gardner, Diane

    2017-04-01

    The shrinkage force exerted by restrained shape memory polymers (SMPs) can potentially be used to close cracks in structural concrete. This paper describes the physical processing and experimental work undertaken to develop high shrinkage die-drawn polyethylene terephthalate (PET) SMP tendons for use within a crack closure system. The extrusion and die-drawing procedure used to manufacture a series of PET tendon samples is described. The results from a set of restrained shrinkage tests, undertaken at differing activation temperatures, are also presented along with the mechanical properties of the most promising samples. The stress developed within the tendons is found to be related to the activation temperature, the cross-sectional area and to the draw rate used during manufacture. Comparisons with commercially-available PET strip samples used in previous research are made, demonstrating an increase in restrained shrinkage stress by a factor of two for manufactured PET filament samples.

  15. Acute flexor tendon repairs in zone II.

    PubMed

    Coats, Robert W; Echevarría-Oré, Julio C; Mass, Daniel P

    2005-05-01

    Flexor tendon repair in zone II is still a technically demanding procedure, but the outcomes have become more predictable and satisfying. Of keystone importance for obtaining the goals of normal strength and gliding of repaired flexor tendons are an atraumatic surgical technique, an appropriate suture material, a competent pulley system, and the use of early motion rehabilitation protocols. The overall goal of hand and finger function also implies timely addressing of neurovascular injuries. New devices such as the TenoFix (Ortheon Medical; Winter Park, Florida) have shown adequate strength in the laboratory but are bulky and untested for work of flexion. Insufficient clinical data and high cost may prevent widespread use.

  16. Flexor Tendon Pulley Injuries in Rock Climbers.

    PubMed

    King, Elizabeth A; Lien, John R

    2017-02-01

    Closed pulley ruptures are rare in the general population but occur more frequently in rock climbers due to biomechanical demands on the hand. Injuries present with pain and swelling over the affected pulley, and patients may feel or hear a pop at the time of injury. Sequential pulley ruptures are required for clinical bowstringing of the flexor tendons. Ultrasound confirms diagnosis of pulley rupture and evaluates degree of displacement of the flexor tendons. Isolated pulley ruptures frequently are treated conservatively with early functional rehabilitation. Sequential pulley ruptures require surgical reconstruction. Most climbers are able to return to their previous activity level.

  17. Tendon ruptures: mallet, flexor digitorum profundus.

    PubMed

    Yeh, Peter C; Shin, Steven S

    2012-08-01

    Mallet injuries are the most common closed tendon injury in the athlete. Flexor digitorum profundus ruptures are rare in baseball, but are common injuries in contact sports. The diagnosis for each condition is based on clinical examination, although radiographs should be evaluated for a possible bony component. Treatment for mallet injury depends on the athlete's goals of competition and understanding of the consequences of any treatment chosen. Gripping, throwing, and catching would be restricted or impossible with the injured finger immobilized. Treatment of FDP ruptures is almost always surgical and requires reattachment of the torn tendon to the distal phalanx.

  18. Development and evaluation of a removable tissue-engineered muscle with artificial tendons.

    PubMed

    Nakamura, Tomohiro; Takagi, Shunya; Kamon, Takafumi; Yamasaki, Ken-Ichi; Fujisato, Toshia

    2017-02-01

    Tissue-engineered skeletal muscles were potentially useful as physiological and biochemical in vitro models. Currently, most of the similar models were constructed without tendons. In this study, we aimed to develop a simple, highly versatile tissue-engineered muscle with artificial tendons, and to evaluate the contractile, histological and molecular dynamics during differentiation. C2C12 cells were embedded in a cold type-І collagen gel and placed between two artificial tendons on a silicone sheet. The construct shrank and tightly attached to the artificial tendons with differentiation, finally detaching from the silicone sheet within 1 week of culture onset. We successfully developed a tissue-engineered skeletal muscle with two artificial tendons from C2C12 myoblasts embedded in type-І collagen gel. The isometric twitch contractile force (TCF) significantly increased during differentiation. Time to Peak Tension (TPT) and Half-Relaxation Time (1/2RT) were significantly shortened during differentiation. Myogenic regulatory factors were maximally expressed at 2 weeks, and subsequently decreased at 3 weeks of culture. Histological analysis indicated that myotube formation increased markedly from 2 weeks and well-ordered sarcomere structures were observed on the surface of the 3D engineered muscle at 3 weeks of culture. These results suggested that robust muscle structure occurred by 3 weeks in the tissue-engineered skeletal muscle. Moreover, during the developmental process, the artificial tendons might contribute to well-ordered sarcomere formation. Our results indicated that this simple culture system could be used to evaluate the effects of various pharmacological and mechanical cues on muscle contractility in a variety of research areas.

  19. Lubricin in human achilles tendon: The evidence of intratendinous sliding motion and shear force in achilles tendon.

    PubMed

    Sun, Yu-Long; Wei, Zhuang; Zhao, Chunfeng; Jay, Gregory D; Schmid, Thomas M; Amadio, Peter C; An, Kai-Nan

    2015-06-01

    Achilles tendon is one of the most commonly injured tendons. Mechanical force is regarded as a major causative factor. However, the biomechanics of Achilles tendon and mechanical mechanism of the injuries are unclear. Lubricin expresses at regions exposed to sliding motion and shear force in a number of tissues. This study investigated the distribution and concentration of lubricin in human Achilles tendons for better understanding the biomechanics of Achilles tendon. Achilles tendons were harvested from nine cadavers. Lubricin was extracted from various locations proximal to the calcaneal insertion and quantified with ELISA. The distribution of lubricin was investigated with immunohistochemistry. Lubricin was mainly identified at the interfaces of tendon fascicles, especially in the mid-portion of the tendon. The concentration of lubricin in Achilles tendons varied by individual and the distance from its calcaneal insertion. The distal portion of the tendon had a higher concentration of lubricin than the proximal regions of the tendon. This study suggests the presence of intratendinous sliding motion of fascicles and shear force at interfaces of fascicles in human Achilles tendon. Shear force could be an important mechanical factor for the development of Achilles tendinopathy and rupture.

  20. Monitoring of Grouting Compactness in a Post-Tensioning Tendon Duct Using Piezoceramic Transducers.

    PubMed

    Jiang, Tianyong; Kong, Qingzhao; Wang, Wenxi; Huo, Linsheng; Song, Gangbing

    2016-08-22

    A post-tensioning tendon duct filled with grout can effectively prevent corrosion of the reinforcement, maintain bonding behavior between the reinforcement and concrete, and enhance the load bearing capacity of concrete structures. In practice, grouting of the post-tensioning tendon ducts always causes quality problems, which may reduce structural integrity and service life, and even cause accidents. However, monitoring of the grouting compactness is still a challenge due to the invisibility of the grout in the duct during the grouting process. This paper presents a stress wave-based active sensing approach using piezoceramic transducers to monitor the grouting compactness in real time. A segment of a commercial tendon duct was used as research object in this study. One lead zirconate titanate (PZT) piezoceramic transducer with marble protection, called a smart aggregate (SA), was bonded on the tendon and installed in the tendon duct. Two PZT patch sensors were mounted on the top outside surface of the duct, and one PZT patch sensor was bonded on the bottom outside surface of the tendon duct. In the active sensing approach, the SA was used as an actuator to generate a stress wave and the PZT sensors were utilized to detect the wave response. Cement or grout in the duct functions as a wave conduit, which can propagate the stress wave. If the cement or grout is not fully filled in the tendon duct, the top PZT sensors cannot receive much stress wave energy. The experimental procedures simulated four stages during the grout pouring process, which includes empty status, half grouting, 90% grouting, and full grouting of the duct. Experimental results show that the bottom PZT sensor can detect the signal when the grout level increases towards 50%, when a conduit between the SA and PZT sensor is formed. The top PZT sensors cannot receive any signal until the grout process is completely finished. The wavelet packet-based energy analysis was adopted in this research to

  1. Monitoring of Grouting Compactness in a Post-Tensioning Tendon Duct Using Piezoceramic Transducers

    PubMed Central

    Jiang, Tianyong; Kong, Qingzhao; Wang, Wenxi; Huo, Linsheng; Song, Gangbing

    2016-01-01

    A post-tensioning tendon duct filled with grout can effectively prevent corrosion of the reinforcement, maintain bonding behavior between the reinforcement and concrete, and enhance the load bearing capacity of concrete structures. In practice, grouting of the post-tensioning tendon ducts always causes quality problems, which may reduce structural integrity and service life, and even cause accidents. However, monitoring of the grouting compactness is still a challenge due to the invisibility of the grout in the duct during the grouting process. This paper presents a stress wave-based active sensing approach using piezoceramic transducers to monitor the grouting compactness in real time. A segment of a commercial tendon duct was used as research object in this study. One lead zirconate titanate (PZT) piezoceramic transducer with marble protection, called a smart aggregate (SA), was bonded on the tendon and installed in the tendon duct. Two PZT patch sensors were mounted on the top outside surface of the duct, and one PZT patch sensor was bonded on the bottom outside surface of the tendon duct. In the active sensing approach, the SA was used as an actuator to generate a stress wave and the PZT sensors were utilized to detect the wave response. Cement or grout in the duct functions as a wave conduit, which can propagate the stress wave. If the cement or grout is not fully filled in the tendon duct, the top PZT sensors cannot receive much stress wave energy. The experimental procedures simulated four stages during the grout pouring process, which includes empty status, half grouting, 90% grouting, and full grouting of the duct. Experimental results show that the bottom PZT sensor can detect the signal when the grout level increases towards 50%, when a conduit between the SA and PZT sensor is formed. The top PZT sensors cannot receive any signal until the grout process is completely finished. The wavelet packet-based energy analysis was adopted in this research to

  2. Revisiting the continuum model of tendon pathology: what is its merit in clinical practice and research?

    PubMed Central

    Cook, J L; Rio, E; Purdam, C R; Docking, S I

    2016-01-01

    The pathogenesis of tendinopathy and the primary biological change in the tendon that precipitates pathology have generated several pathoaetiological models in the literature. The continuum model of tendon pathology, proposed in 2009, synthesised clinical and laboratory-based research to guide treatment choices for the clinical presentations of tendinopathy. While the continuum has been cited extensively in the literature, its clinical utility has yet to be fully elucidated. The continuum model proposed a model for staging tendinopathy based on the changes and distribution of disorganisation within the tendon. However, classifying tendinopathy based on structure in what is primarily a pain condition has been challenged. The interplay between structure, pain and function is not yet fully understood, which has partly contributed to the complex clinical picture of tendinopathy. Here we revisit and assess the merit of the continuum model in the context of new evidence. We (1) summarise new evidence in tendinopathy research in the context of the continuum, (2) discuss tendon pain and the relevance of a model based on structure and (3) describe relevant clinical elements (pain, function and structure) to begin to build a better understanding of the condition. Our goal is that the continuum model may help guide targeted treatments and improved patient outcomes. PMID:27127294

  3. [Traumatic and degenerative tendon lesions of the hand].

    PubMed

    Schöffl, V; Winkelmann, H-P

    2010-12-01

    Tendon lesions are the second most common injury in the hand and therefore an important factor in orthopedic patients. Most injuries are open injuries to the flexor or extensor tendons; nevertheless, also less frequent injuries such as damage to the functional system of tendon sheath and pulley or dull avulsions need to be considered. Besides the clinical examination, ultrasound and MRI have proven to be important diagnostic tools. In the postoperative course of flexor tendon injuries, the principle of early passive movement is important to trigger "intrinsic" tendon healing to guarantee a good outcome.

  4. Mechanical properties of UV irradiated rat tail tendon (RTT) collagen.

    PubMed

    Sionkowska, Alina; Wess, Tim

    2004-04-01

    The mechanical properties of RTT collagen tendon before and after UV irradiation have been investigated by mechanical testing (Instron). Air-dried tendon were submitted to treatment with UV irradiation (wavelength 254 nm) for different time intervals. The changes in such mechanical properties as breaking strength and percentage elongation have been investigated. The results have shown, that the mechanical properties of the tendon were greatly affected by time of UV irradiation. Ultimate tensile strength and ultimate percentage elongation decreased after UV irradiation of the tendon. Increasing UV irradiation leads to a decrease in Young's modulus of the tendon.

  5. Development of the human Achilles tendon enthesis organ.

    PubMed

    Shaw, H M; Vázquez, Osorio T; McGonagle, D; Bydder, G; Santer, R M; Benjamin, M

    2008-12-01

    The attachment of the Achilles tendon is part of an 'enthesis organ' that reduces stress concentration at the hard-soft tissue interface. The organ also includes opposing sesamoid and periosteal fibrocartilages, a bursa and Kager's fat pad. In addition, the deep crural and plantar fasciae contribute to Achilles stress dissipation and could also be regarded as components. Here we describe the sequence in which these various tissues differentiate. Serial sections of feet from spontaneously aborted foetuses (crown rump lengths 22-322 mm) were examined. All slides formed part of an existing collection of histologically sectioned embryological material, obtained under Spanish law and housed in the Universidad Complutense, Madrid. From the earliest stages, it was evident that the Achilles tendon and plantar fascia had a mutual attachment to the calcaneal perichondrium. The first components of the enthesis organ to appear (in the 45-mm foetus) were the retrocalcaneal bursa and the crural fascia. The former developed by cavitation within the mesenchyme that later gave rise to Kager's fat pad. The tip of the putative fat pad protruded into the developing bursa in the 110-mm foetus and fully differentiated adipocytes were apparent in the 17-mm foetus. All three fibrocartilages were first recognisable in the 332-mm foetus--at which time adipogenesis had commenced in the heel fat pad. The sequence in which the various elements became apparent suggests that bursal formation and the appearance of the crural fascia may be necessary to facilitate the foot movements that subsequently lead to fibrocartilage differentiation. The later commencement of adipogenesis in the heel than in Kager's pad probably reflects the non-weight environment in utero. The direct continuity between plantar fascia and Achilles tendon that is characteristic of the adult reflects the initial attachment of both structures to the calcaneal perichondrium rather than to the skeletal anlagen itself.

  6. Severe extensor tendon attrition and multiple tendon ruptures resulting from Kienböck's disease.

    PubMed

    Ramkumar, S; Josty, I C; Sykes, P J

    2000-12-01

    Kienböck's disease is a rare but recognized cause of chronic wrist pain. Occasionally, complications arise leading to tendon rupture. The authors present the first reported case of attrition to all extensors of the hand, and extensor tendon rupture to the little finger in a patient with a 45-year history of Kienböck's disease. This is also the first reported incidence of this complication in whites. Clinical features, surgical management, and the successful outcome are discussed.

  7. 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

  8. Muscle - tendon unit mechanical and morphological properties and sprint performance.

    PubMed

    Stafilidis, Savvas; Arampatzis, Adamantios

    2007-07-01

    The objective of this study was to determine whether sprint performance is related to the mechanical (elongation - force relationship of the tendon and aponeurosis, muscle strength) and morphological (fascicle length, pennation angle, muscle thickness) properties of the quadriceps femoris and triceps surae muscle - tendon units. Two groups of sprinters (slow, n = 11; fast, n = 17) performed maximal isometric knee extension and plantar flexion contractions on a dynamometer at 11 different muscle - tendon unit lengths. Elongation of the tendon and aponeurosis of the gastrocnemius medialis and the vastus lateralis was measured using ultrasonography. We observed no significant differences in maximal joint moments at the ankle and knee joints or morphological properties of the gastrocnemius medialis and vastus lateralis between groups (P > 0.05). The fast group exhibited greater elongation of the vastus lateralis tendon and aponeurosis at a given tendon force, and greater maximal elongation of the vastus lateralis tendon and aponeurosis during maximum voluntary contraction (P < 0.05). Furthermore, maximal elongation of the vastus lateralis tendon and aponeurosis showed a significant correlation with 100-m sprint times (r = -0.567, P = 0.003). For the elongation - force relationship at the gastrocnemius medialis tendon and aponeurosis, the two groups recorded similar values. It is suggested that the greater elongation of the vastus lateralis tendon and aponeurosis of the fast group benefits energy storage and return as well as the shortening velocity of the muscle - tendon unit.

  9. Abductor pollicis longus tendon division with swan neck thumb deformity.

    PubMed

    Zacharia, Balaji; Puthezhath, Kishore

    2012-08-01

    Swan neck thumb deformity can be caused by osteoarthritis, rheumatoid arthritis, systemic lupus erythematosus, tendon transfers and paralytic diseases. Abductor pollicis longus is one of the major stabilizing tendon of the carpometacarpal joint of thumb. To the best of our knowledge, swan neck thumb deformity owing to division of abductor pollicis longus tendon is rare. In this article, we describe a case of isolated division of abductor pollicis longus tendon presenting with swan-neck deformity of thumb and discuss the mechanism, management and outcome. The patient was treated by repair of the divided tendon using palmaris longus tendon graft. At approximately 107 weeks following treatment, the patient was having full range of thumb movement and the deformity completely disappeared. We also describe the unusual mechanism whereby an isolated division of abductor pollicis longus tendon results in swan neck thumb deformity. Level of clinical evidence IV.

  10. A new strain energy function for modelling ligaments and tendons whose fascicles have a helical arrangement of fibrils.

    PubMed

    Shearer, Tom

    2015-09-18

    A new strain energy function for the hyperelastic modelling of ligaments and tendons whose fascicles have a helical arrangement of fibrils is derived. The stress-strain response of a single fascicle whose fibrils exhibit varying levels of crimp throughout its radius is calculated and used to determine the form of the strain energy function. The new constitutive law is used to model uniaxial extension test data for human patellar tendon and is shown to provide an excellent fit, with the average relative error being 9.8%. It is then used to model shear and predicts that the stresses required to shear a tendon are much smaller than those required to uniaxially stretch it to the same strain level. Finally, the strain energy function is used to model ligaments and tendons whose fascicles are helical, and the relative effects of the fibril helix angle, the fascicle helix angle and the fibril crimp variable are compared. It is shown that they all have a significant effect; the fibril crimp variable governs the non-linearity of the stress-strain curve, whereas the helix angles primarily affect its stiffness. Smaller values of the helix angles lead to stiffer tendons; therefore, the model predicts that one would expect to see fewer helical sub-structures in stiff positional tendons, and more in those that are required to be more flexible.

  11. [Flexor tendon pulley system: anatomy, pathology, treatment].

    PubMed

    Moutet, F

    2003-02-01

    Flexor tendon pulley has been very early noticed and described. Terminology usually accepted recognizes 6 arcifom pulleys (A0 to A5) and 3 cruciform pulleys (C1 to C3). Anatomy and physiology of this flexor tendon gliding and reflection system at the level of the digital sheet are exposed. The integrity necessity of this system became obvious regarding the flexor tendons repair. Four main pathologies may be concerned: the trigger finger congenital or progressive, due to a chondroid metaplasia of the A1 pulley; tenosynovial ganglions arising at the weak point between A1 and A2 pulley; lesions of the flexor tendon sheet during traumatic lacerations or surgical repairs; quite experimental lesions creating isolated ruptures of one or several pulleys which occur during sport practice, especially high level rock climbing. The repair techniques are exposed to allow to graduate and hierarchy the reparation technique regarding the pathology. A2 and A4 repair is always indicated. The best reconstruction material is an extensor retinaculum graft. But its poor surface available often draws to use conventional palmaris longus free graft.

  12. Collagen V expression is crucial in regional development of the supraspinatus tendon.

    PubMed

    Connizzo, Brianne K; Adams, Sheila M; Adams, Thomas H; Birk, David E; Soslowsky, Louis J

    2016-12-01

    Manipulations in cell culture and mouse models have demonstrated that reduction of collagen V results in altered fibril structure and matrix assembly. A tissue-dependent role for collagen V in determining mechanical function was recently established, but its role in determining regional properties has not been addressed. The objective of this study was to define the role(s) of collagen V expression in establishing the site-specific properties of the supraspinatus tendon. The insertion and midsubstance of tendons from wild type, heterozygous and tendon/ligament-specific null mice were assessed for crimp morphology, fibril morphology, cell morphology, as well as total collagen and pyridinoline cross-link (PYD) content. Fibril morphology was altered at the midsubstance of both groups with larger, but fewer, fibrils and no change in cell morphology or collagen compared to the wild type controls. In contrast, a significant disruption of fibril assembly was observed at the insertion site of the null group with the presence of structurally aberrant fibrils. Alterations were also present in cell density and PYD content. Altogether, these results demonstrate that collagen V plays a crucial role in determining region-specific differences in mouse supraspinatus tendon structure. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2154-2161, 2016.

  13. Engineered stem cell niche matrices for rotator cuff tendon regenerative engineering

    PubMed Central

    Peach, M. Sean; Ramos, Daisy M.; Morozowich, Nicole L.; Mazzocca, Augustus D.; Doty, Steven B.; Allcock, Harry R.; Kumbar, Sangamesh G.; Laurencin, Cato T.

    2017-01-01

    Rotator cuff (RC) tears represent a large proportion of musculoskeletal injuries attended to at the clinic and thereby make RC repair surgeries one of the most widely performed musculoskeletal procedures. Despite the high incidence rate of RC tears, operative treatments have provided minimal functional gains and suffer from high re-tear rates. The hypocellular nature of tendon tissue poses a limited capacity for regeneration. In recent years, great strides have been made in the area of tendonogenesis and differentiation towards tendon cells due to a greater understanding of the tendon stem cell niche, development of advanced materials, improved scaffold fabrication techniques, and delineation of the phenotype development process. Though in vitro models for tendonogenesis have shown promising results, in vivo models have been less successful. The present work investigates structured matrices mimicking the tendon microenvironment as cell delivery vehicles in a rat RC tear model. RC injuries augmented with a matrix delivering rat mesenchymal stem cells (rMSCs) showed enhanced regeneration over suture repair alone or repair with augmentation, at 6 and 12-weeks post-surgery. The local delivery of rMSCs led to increased mechanical properties and improved tissue morphology. We hypothesize that the mesenchymal stem cells function to modulate the local immune and bioactivity environment through autocrine/paracrine and/or cell homing mechanisms. This study provides evidence for improved tendon healing with biomimetic matrices and delivered MSCs with the potential for translation to larger, clinical animal models. The enhanced regenerative healing response with stem cell delivering biomimetic matrices may represent a new treatment paradigm for massive RC tendon tears. PMID:28369135

  14. Ultrasound Elasticity Imaging for Determining the Mechanical Properties of Human Posterior Tibial Tendon: A Cadaveric Study

    PubMed Central

    Yuan, Justin S.; Heden, Gregory J.; Szivek, John A.; Taljanovic, Mihra S.; Latt, L. Daniel; Witte, Russell S.

    2016-01-01

    Posterior tibial tendon dysfunction (PTTD) is a common degenerative condition leading to a severe impairment of gait. There is currently no effective method to determine whether a patient with advanced PTTD would benefit from several months of bracing and physical therapy or ultimately require surgery. Tendon degeneration is closely associated with irreversible degradation of its collagen structure, leading to changes to its mechanical properties. If these properties could be monitored in vivo, they could be used to quantify the severity of tendonosis and help determine the appropriate treatment. The goal of this cadaveric study was, therefore, to develop and validate ultrasound elasticity imaging (UEI) as a potentially noninvasive technique for quantifying tendon mechanical properties. Five human cadaver feet were mounted in a materials testing system (MTS), while the posterior tibial tendon (PTT) was attached to a force actuator. A portable ultrasound scanner collected 2-D data during loading cycles. Young’s modulus was calculated from the strain, loading force, and cross-sectional area of the PTT. Average Young’s modulus for the five tendons was (0.45 ± 0.16 GPa) using UEI, which was consistent with simultaneous measurements made by the MTS across the whole tendon (0.52 ± 0.18 GPa). We also calculated the scaling factor (0.12 ± 0.01) between the load on the PTT and the inversion force at the forefoot, a measurable quantity in vivo. This study suggests that UEI could be a reliable in vivo technique for estimating the mechanical properties of the PTT, and as a clinical tool, help guide treatment decisions for advanced PTTD and other tendinopathies. PMID:25532163

  15. The influence of testing angle on the biomechanical properties of the rat supraspinatus tendon.

    PubMed

    Newton, Michael D; Davidson, Abigail A; Pomajzl, Ryan; Seta, Joseph; Kurdziel, Michael D; Maerz, Tristan

    2016-12-08

    Rotator cuff tears are a common shoulder pathology. The rat supraspinatus tendon model is commonly employed for preclinical assessment of rotator cuff pathology or regeneration. However, there is a lack of a standardized biomechanical testing protocol; previous studies have tested the tendon at abduction angles ranging from -15° to 90°. This study aimed to assess the effect of abduction/testing angle on the biomechanical properties of the rat supraspinatus tendon. Fourty-eight shoulders (n=12/group) from healthy Sprague-Dawley rats were randomized to 4 testing angle groups: 0° (corresponding to 90° abduction), 30°, 60°, and 90° (0° abduction). Biomechanical testing of the supraspinatus was performed, consisting of stress-relaxation and load-to-failure. Mechanical properties were calculated, and nonlinear tensile modeling was performed via the Quasilinear Viscoelastic (QLV) and Structurally Based Elastic (SBE) models. Results indicate that testing angle significantly affects supraspinatus tendon biomechanics. Stiffness and modulus significantly decreased with increasing testing angle (stiffness: 20.93±5.8N/mm at 0° vs. 6.12±1.0N/mm at 90°, P<.001; modulus: 59.51±34.0MPa at 0° vs. 22.37±7.4MPa at 90°, P=.002). Testing angle correlated significantly to ultimate strain, yield strain, and all coefficients of the SBE and QLV models, implying differences in collagen fiber crimp patterns and viscoelastic behavior as a function of testing angle. These results suggest that differences in testing methodology, in particular testing angle, significantly affect the measured mechanical properties of the supraspinatus tendon. Future studies may consider utilizing testing angles of 0°-30°, at which tendon stiffness is maximized, and full standardization of rat rotator cuff testing protocols is necessary.

  16. The role of tendon microcirculation in Achilles and patellar tendinopathy.

    PubMed

    Knobloch, Karsten

    2008-04-30

    Tendinopathy is of distinct interest as it describes a painful tendon disease with local tenderness, swelling and pain associated with sonographic features such as hypoechogenic texture and diameter enlargement. Recent research elucidated microcirculatory changes in tendinopathy using laser Doppler flowmetry and spectrophotometry such as at the Achilles tendon, the patellar tendon as well as at the elbow and the wrist level. Tendon capillary blood flow is increased at the point of pain. Tendon oxygen saturation as well as tendon postcapillary venous filling pressures, determined non-invasively using combined Laser Doppler flowmetry and spectrophotometry, can quantify, in real-time, how tendon microcirculation changes over with pathology or in response to a given therapy. Tendon oxygen saturation can be increased by repetitive, intermittent short-term ice applications in Achilles tendons; this corresponds to 'ischemic preconditioning', a method used to train tissue to sustain ischemic damage. On the other hand, decreasing tendon oxygenation may reflect local acidosis and deteriorating tendon metabolism. Painful eccentric training, a common therapy for Achilles, patellar, supraspinatus and wrist tendinopathy decreases abnormal capillary tendon flow without compromising local tendon oxygenation. Combining an Achilles pneumatic wrap with eccentric training changes tendon microcirculation in a different way than does eccentric training alone; both approaches reduce pain in Achilles tendinopathy. The microcirculatory effects of measures such as extracorporeal shock wave therapy as well as topical nitroglycerine application are to be studied in tendinopathy as well as the critical question of dosage and maintenance. Interestingly it seems that injection therapy using color Doppler for targeting the area of neovascularisation yields to good clinical results with polidocanol sclerosing therapy, but also with a combination of epinephrine and lidocaine.

  17. Vascular alterations in the rabbit patellar tendon after surgical incision

    PubMed Central

    DOSCHAK, M. R.; MATYAS, J. R.; HART, D. A.; BRAY, R. C.

    2001-01-01

    vasodilation was measured in the contralateral PTs at both early time intervals, but was not seen by the later 42 d interval. With respect to PT geometric properties in the experimental animals, a larger PT results as the tendon matrix and blood vessels remodel. PT cross-sectional area increased rapidly by 3 d to 1·3 times control values, and remained significantly elevated at 42 d postinjury. Morphological assessments demonstrated the disruption of matrix organisation by vascular and soft tissue components associated with the longitudinal incisions. Substantial changes in matrix organisation persisted at 42 d after surgery. These findings suggest that open longitudinal incision of the PT increases the vascular supply to deep tendon early after injury. These changes probably arise through both vasomotor and angiogenic activity in the tissue. Since PT blood flow and vascular volume return towards control levels after 6 wk but structural features remain disorganised, we propose that vascular remodelling is more rapid and complete than matrix remodelling after surgical incision of the PT. PMID:11430691

  18. 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.

  19. Anatomic variation of the 5th extensor tendon compartment and extensor digiti minimi tendon.

    PubMed

    Tanaka, Toshikazu; Moran, Steven L; Zhao, Chunfeng; Zobitz, Mark E; An, Kai-Nan; Amadio, Peter C

    2007-08-01

    Anatomic variation within the 5th extensor compartment may contribute to the development of tenosynovitis and limit the usefulness of the extensor digiti minimi (EDM) for tendon transfer. The purpose of this study was to assess the anatomic variation of the EDM tendon and its surrounding retinaculum, with particular attention to anatomical variation between specimens. Forty-one fresh cadaver hands were dissected. The length of the 5th compartment retinaculum was noted. The incidence of an intercompartmental septum was noted in each specimen as well as the type of tendinous attachments present between the EDM and extensor digitorum communis (EDC) tendons. The presence and length of any accessory retinacular bands distal to the edge of proper extensor retinaculum was also noted. Only one specimen contained a single EDM tendon, while 71% (n = 29) of specimens contained two slips and 23% (n = 9) had three slips; 24% (n = 10) of EDC tendons had no slip to the small finger, while 61% (n = 25) of specimens had a single slip to the small finger. The EDC's contribution to the small finger was found to be an independent tendon in 42% of cases (n = 17), while 34% (n = 14) of specimens were found to have a common EDC slip, which branched to both the ring and small finger. Three EDM tendons divided distal to the extensor retinaculum, while the remaining EDM tendons divided beneath or proximal to the extensor retinaculum. Seventy-three percent (n = 30) of the specimens had an accessory retinacular band surrounding the EDM tendon identified at the base of the 5th metacarpal. Eighty-eight percent (n = 36) of hands had a septum between the EDM slips. The surgeon should be aware of variability within the 5th dorsal compartment in cases of trauma and in cases of tendon transfer. In our series 30 of 41 specimens were noted to contain an accessory dorsal retinacular band surrounding the EDM and 36 specimens were noted to contain a septum within the 5th compartment. The presence of an

  20. Fluorescence spectroscopy and birefringence of molecular changes in maturing rat tail tendon.

    PubMed

    Korol, Renee M; Finlay, Helen M; Josseau, Melanie J; Lucas, Alexandra R; Canham, Peter B

    2007-01-01

    Tissue remodeling during maturation, wound healing, and response to vascular stress involves molecular changes of collagen and elastin in the extracellular matrix (ECM). Two optical techniques are effective for investigating these changes--laser-induced fluorescence (LIF) spectroscopy and polarizing microscopy. LIF spectroscopy integrates the signal from both elastin and collagen cross-linked structure, whereas birefringence is a measure of only collagen. Our purpose is (1) to evaluate the rat tail tendon (RTT) spectroscopy against data from purified extracted protein standards and (2) to correlate the two optical techniques in the study of RTT and skin. Spectra from tissue samples from 27 male rats and from extracted elastin and collagen were obtained using LIF spectroscopy (357 nm). Birefringence was measured on 5-mum histological sections of the same tissue. Morphometric analysis reveals that elastin represents approximately 10% of tendon volume and contributes to RTT fluorescence. RTT maximum fluorescence emission intensity (FEI(max)), which includes collagen and elastin, increases with animal weight (R(2)=0.64). Birefringence, when plotted against weight, increases to a plateau (nonlinear correlation: R(2)=0.90), tendon having greater birefringence than skin. LIF spectroscopy and collagen fiber birefringence are shown to provide complementary measurements of molecular structure (tendon birefringence versus FEI(max) at R(2)=0.60).

  1. Polarization-dependent optical second-harmonic imaging of a rat-tail tendon.

    PubMed

    Stoller, Patrick; Kim, Beop-Min; Rubenchik, Alexander M; Reiser, Karen M; Da Silva, Luiz B

    2002-04-01

    Using scanning confocal microscopy, we measure the backscattered second harmonic signal generated by a 100 fs laser in rat-tail tendon collagen. Damage to the sample is avoided by using a continuous scanning technique, rather than measuring the signal at discrete points. The second harmonic signal varies by about a factor of 2 across a single cross section of the rat-tail tendon fascicle. The signal intensity depends both on the collagen organization and the backscattering efficiency. This implies that we cannot use intensity measurements alone to characterize collagen structure. However, we can infer structural information from the polarization dependence of the second harmonic signal. Axial and transverse scans for different linear polarization angles of the input beam show that second harmonic generation (SHG) in the rat-tail tendon depends strongly on the polarization of the input laser beam. We develop an analytical model for the SHG as a function of the polarization angle in the rat-tail tendon. We apply this model in determining the orientation of collagen fibrils in the fascicle and the ratio gamma between the two independent elements of the second-order nonlinear susceptibility tensor. There is a good fit between our model and the measured data.

  2. 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.

  3. Flexor tendon injuries. Part 5. Flexor tenolysis, rehabilitation and results.

    PubMed

    Strickland, J W

    1987-03-01

    In this five-part series, we have attempted to review our current understanding of flexor tendon anatomy, physiology, biomechanics, healing and adhesion formation around a repaired tendon. The methods of acute flexor tendon repair, conventional free tendon grafting, staged flexor tendon reconstruction and pulley restoration have been discussed as well as flexor tenolysis, rehabilitation and results. From these articles it may be seen that flexor tendon surgery is a complex and difficult art which requires a thorough appreciation of the normal flexor tendon system, the exact status of that system following injury and a strong understanding of the techniques which may be best utilized to restore flexor tendon function. The procedures described require both technical skill and experience and postoperative therapy programs must be carefully instituted based on the unique status of each patient. With the important advances occurring in many areas of flexor tendon surgery, it is realistic to believe that in the near future the techniques described in these articles may be substantially altered and modified. Results will continue to improve until the patient and surgeon can realistically expect to return most digits to nearly full function after flexor tendon interruption.

  4. The Cellular Biology of Flexor Tendon Adhesion Formation

    PubMed Central

    Wong, Jason K.F.; Lui, Yin H.; Kapacee, Zoher; Kadler, Karl E.; Ferguson, Mark W. J.; McGrouther, Duncan A.

    2009-01-01

    Intrasynovial flexor tendon injuries of the hand can frequently be complicated by tendon adhesions to the surrounding sheath, limiting finger function. We have developed a new tendon injury model in the mouse to investigate the three-dimensional cellular biology of intrasynovial flexor tendon healing and adhesion formation. We investigated the cell biology using markers for inflammation, proliferation, collagen synthesis, apoptosis, and vascularization/myofibroblasts. Quantitative immunohistochemical image analysis and three-dimensional reconstruction with cell mapping was performed on labeled serial sections. Flexor tendon adhesions were also assessed 21 days after wounding using transmission electron microscopy to examine the cell phenotypes in the wound. When the tendon has been immobilized, the mouse can form tendon adhesions in the flexor tendon sheath. The cell biology of tendon healing follows the classic wound healing response of inflammation, proliferation, synthesis, and apoptosis, but the greater activity occurs in the surrounding tissue. Cells that have multiple “fibripositors” and cells with cytoplasmic protrusions that contain multiple large and small diameter fibrils can be found in the wound during collagen synthesis. In conclusion, adhesion formation occurs due to scarring between two damaged surfaces. The mouse model for flexor tendon injury represents a new platform to study adhesion formation that is genetically tractable. PMID:19834058

  5. Decellularized and Engineered Tendons as Biological Substitutes: A Critical Review

    PubMed Central

    Lovati, Arianna B.; Bottagisio, Marta; Moretti, Matteo

    2016-01-01

    Tendon ruptures are a great burden in clinics. Finding a proper graft material as a substitute for tendon repair is one of the main challenges in orthopaedics, for which the requirement of a biological scaffold would be different for each clinical application. Among biological scaffolds, the use of decellularized tendon-derived matrix increasingly represents an interesting approach to treat tendon ruptures. We analyzed in vitro and in vivo studies focused on the development of efficient protocols for the decellularization and for the cell reseeding of the tendon matrix to obtain medical devices for tendon substitution. Our review considered also the proper tendon source and preclinical animal models with the aim of entering into clinical trials. The results highlight a wide panorama in terms of allogenic or xenogeneic tendon sources, specimen dimensions, physical or chemical decellularization techniques, and the cell type variety for reseeding from terminally differentiated to undifferentiated mesenchymal stem cells and their static or dynamic culture employed to generate implantable constructs tested in different animal models. We try to identify the most efficient approach to achieve an optimal biological scaffold for biomechanics and intrinsic properties, resembling the native tendon and being applicable in clinics in the near future, with particular attention to the Achilles tendon substitution. PMID:26880985

  6. Cryotherapy suppresses tendon inflammation in an animal model

    PubMed Central

    Zhang, Jianying; Pan, Tiffany; Wang, James H.-C.

    2015-01-01

    Summary Cryotherapy (or cold treatment) has been a popular treatment to relieve pain caused by injuries to tissues such as tendons. However, the exact mechanisms behind the beneficial effects of cryotherapy in tendons remain largely unclear. As prostaglandin E2 (PGE2) is known to be a major mediator of acute inflammation in tissues, which is related to tissue pain, we hypothesized that the beneficial effects of cryotherapy in tendons are mediated by downregulation of PGE2 levels. To test this hypothesis, we applied cold treatment to mouse patellar and Achilles tendons using two animal models: exhaustive mouse treadmill running and acute mouse tendon injury by needle penetration. We then measured the levels of PGE2 and protein expression levels of COX-2, an enzyme responsible for PGE2 production in tissues, under both experimental conditions. We found that treadmill running increased PGE2 levels in both patellar and Achilles tendons compared to control mice without running. Cold treatment for 30 min after treadmill running was sufficient to reduce PGE2 levels to near baseline control levels in both tendons. An extension of cold treatment to 60 min resulted only in a marginal decrease in patellar tendons, but a marked decrease in Achilles tendons. Moreover, COX-2 protein levels in both tendons were also lowered by cold treatment, suggesting that the reduction of PGE2 levels in tendons by cold treatment is at least in part due to the decreased COX-2 expression. Similarly, in the acutely injured tendons, 30 min of cold treatment after needle penetration reduced PGE2 levels when compared to the controls at room temperature (22°C). This decrease was sustained up to at least 3 h after the administration of cryotherapy. Given that PGE2 is a known pain sensitiser, the results of this study suggest that the ability of cold treatment to reduce pain may be attributable to its ability to decrease PGE2 production in tendons. PMID:26594634

  7. Evaluation of inservice inspections of greased prestressing tendons

    SciTech Connect

    Dougan, J.R.

    1982-09-01

    Prestressed concrete containments in the United States using greased prestressing tendons are inspected periodically to ensure structural integrity and to identify and correct problem areas before they become critical. In the study, an analysis of the available utility surveillance data and an evaluation of the current and proposed guidelines were conducted. Comments from utility and industry personnel were factored into the analysis. The results indicated that the majority of the few incidences of problems or abnormalities that occurred were minor in nature and did not threaten the structural integrity of the containment. All of the available surveillance reports concluded that the respective containments were in good condition. However, the surveillance reports did reveal discrepancies between utilities in the interpretation of the results. Evaluation of the proposed guidelines also revealed areas that could be modified to provide improved results.

  8. Fetal development of the pulley for muscle insertion tendons: A review and new findings related to the tensor tympani tendon.

    PubMed

    Rodríguez-Vázquez, Jose Francisco; Honkura, Yohei; Katori, Yukio; Murakami, Gen; Abe, Hiroshi

    2017-01-01

    The existence of hard tissue pulleys that act to change the direction of a muscle insertion tendon is well known in the human body. These include (1) the trochlea for the extraocular obliquus superior muscle, (2) the pterygoid hamulus for the tensor veli palatini muscle, (3) the deep sulcus on the plantar aspect of the cuboid bone for the peroneus longus tendon, (4) the lesser sciatic notch for the obturator internus muscle, and (5) the bony trochleariformis process for the tensor tympani muscle tendon. In addition, (6) the stapedius muscle tendon shows a lesser or greater angulation at the pyramidal eminence of the temporal bone. Our recent studies have shown that the development of pulleys Nos. 1 and 2 can be explained by a change in the topographical relationship between the pulley and the tendon, that of pulley No. 3 by the rapidly growing calcaneus pushing the tendon, and that of pulley No. 4 by migration of the insertion along the sciatic nerve and gluteus medius tendon. Therefore, in Nos. 1-4, an initially direct tendon curves secondarily and obtains an attachment to the pulley. In case No. 6, the terminal part of the stapedius tendon originates secondarily from the interzone mesenchymal tissue of the incudostapedial joint. In the case of pulley No. 5, we newly demonstrated that its initial phase of development was similar to No. 6, but the tensor tympani tendon achieved a right-angled turn under guidance by a specific fibrous tissue and it migrated along the growing malleus manubrium.

  9. LRT, a tendon-specific leucine-rich repeat protein, promotes muscle-tendon targeting through its interaction with Robo.

    PubMed

    Wayburn, Bess; Volk, Talila

    2009-11-01

    Correct muscle migration towards tendon cells, and the adhesion of these two cell types, form the basis for contractile tissue assembly in the Drosophila embryo. While molecules promoting the attraction of muscles towards tendon cells have been described, signals involved in the arrest of muscle migration following the arrival of myotubes at their corresponding tendon cells have yet to be elucidated. Here, we describe a novel tendon-specific transmembrane protein, which we named LRT due to the presence of a leucine-rich repeat domain (LRR) in its extracellular region. Our analysis suggests that LRT acts non-autonomously to better target the muscle and/or arrest its migration upon arrival at its corresponding tendon cell. Muscles in embryos lacking LRT exhibited continuous formation of membrane extensions despite arrival at their corresponding tendon cells, and a partial failure of muscles to target their correct tendon cells. In addition, overexpression of LRT in tendon cells often stalled muscles located close to the tendon cells. LRT formed a protein complex with Robo, and we detected a functional genetic interaction between Robo and LRT at the level of muscle migration behavior. Taken together, our data suggest a novel mechanism by which muscles are targeted towards tendon cells as a result of LRT-Robo interactions. This mechanism may apply to the Robo-dependent migration of a wide variety of cell types.

  10. Increased unilateral tendon stiffness and its effect on gait 2-6 years after Achilles tendon rupture.

    PubMed

    Agres, A N; Duda, G N; Gehlen, T J; Arampatzis, A; Taylor, W R; Manegold, S

    2015-12-01

    Achilles tendon rupture (ATR) alters tissue composition, which may affect long-term tendon mechanics and ankle function during movement. However, a relationship between Achilles tendon (AT) properties and ankle joint function during gait remains unclear. The primary hypotheses were that (a) post-ATR tendon stiffness and length differ from the noninjured contralateral side and that (b) intra-patient asymmetries in AT properties correlate to ankle function asymmetries during gait, determined by ankle angles and moments. Ultrasonography and dynamometry were used to assess AT tendon stiffness, strain, elongation, and rest length in both limbs of 20 ATR patients 2-6 years after repair. Three-dimensional ankle angles and moments were determined using gait analysis. Injured tendons exhibited increased stiffness, rest length, and altered kinematics, with higher dorsiflexion and eversion, and lower plantarflexion and inversion. Intra-patient tendon stiffness and tendon length ratios were negatively correlated to intra-patient ratios of the maximum plantarflexion moment and maximum dorsiflexion angle, respectively. These results suggest that after surgical ATR repair, higher AT stiffness, but not a longer AT, may contribute to deficits in plantarflexion moment generation. These data further support the claim that post-ATR tendon regeneration results in the production of a tissue that is functionally different than noninjured tendon.

  11. New approaches to magnetic resonance imaging of intervertebral discs, tendons, ligaments, and menisci.

    PubMed

    Bydder, Graeme M

    2002-06-15

    This review article discusses new magnetic resonance techniques for imaging collagen containing structures such as intervertebral discs, tendons, and ligaments. The semisolid collagen in tendons and ligaments is not normally demonstrable with magnetic resonance imaging but may be visualized with magic angle imaging and other techniques. This allows these structures to be studied with methods used for other tissues and organs. The ordered nature of collagen provides a directional signature for the tissues that may be of diagnostic value. Solute transport in these avascular or partially avascular structures can be observed with gadolinium chelates. The time scale of this process is much slower than for other tissues of the body. Solid state imaging techniques applied in applied in material sciences may provide other new approaches to diagnosis of disease in these structures.

  12. Fetal and postnatal development of the patella, patellar tendon and suprapatella in the rabbit; changes in the distribution of the fibrillar collagens

    PubMed Central

    BLAND, YVETTE S.; ASHHURST, DOREEN E.

    1997-01-01

    The development of the patella, its associated tendons, and suprapatella of the rabbit knee joint is described from the 17 d fetus to the mature adult. The patellar tendon (ligament) with the patella on its posterior surface is seen in the 17 d fetus and is fully developed by 1 postnatal wk. It is composed of bundles of types I and V collagens separated by endotenons of types III and V collagens. Anteriorly there is an epitenon of types III and V collagens while synovium and a fat pad cover its posterior surface. In the 25 d fetus, the patella is cartilaginous and is separated from the femoral condyles. The cartilage contains type II collagen, but types I, III and V collagens are found along the articular surface. Ossification starts 1 postnatal wk and at 6 wk only the articular cartilage remains. In addition to type II, types III and V collagens are located around the chondrocyte lacunae. The long anterior junction between the patella and its tendon is fibrocartilaginous at 1 wk, but as ossification proceeds this is replaced by bone. Types I and V collagens are found in this region. The suprapatella on the posterior surface of the quadriceps tendon is first seen 1 wk postnatally as an area of irregularly organised fibres and chondrocyte-like cells. Types I, II, III and V collagens are present from 3 wk onwards. It is compared with the fibrocartilage of other tendons that are under compression. The arrangement of the collagens in the patellar tendon is discussed in relation to its use as a replacement for injured anterior cruciate ligaments. It is suggested that the structural differences between the patellar tendon and anterior cruciate ligament preclude the translocated tendon acquiring mechanical strength similar to that of a normal cruciate ligament. The designation ‘patellar ligament’ as opposed to ‘patellar tendon’ is questioned. It is argued that the term patellar tendon reflects its structure more accurately than patellar ligament. PMID:9147220

  13. Bifurcated intraarticular long head of biceps tendon

    PubMed Central

    Pandey, Vivek; van Laarhoven, Simon Nurettin; Arora, Gaurav; Rao, Sripathi

    2014-01-01

    Though rare, many anomalous origins of long head of the biceps tendon (LHBT) have been reported in the literature. Anatomic variations commonly explained are a third humeral head, anomalous insertion, congenital absence and adherence to the rotator cuff. We report a rare case who underwent shoulder arthroscopy with impingement symptoms where in LHBT was found to be bifurcated with a part attached to superior labrum and the other part to the posterior capsule of joint. Furthermore, intraarticular portion of LHBT was adherent to the undersurface of the supraspinatus tendon. Awareness of such an anatomical aberration during the shoulder arthroscopy is of great importance as it can potentially avoid unnecessary confusion and surgery. PMID:25143652

  14. Chronic Achilles Tendon Rupture Treated with Allograft: A Case Report.

    PubMed

    Restuccia, Giuseppe; Lippi, Alessandro; Casella, Francesco; Citarelli, Carmine; Sacchetti, Federico; Benifei, Maurizio

    2017-02-07

    In clinical practice, chronic Achilles tendon ruptures are uncommon. Usually, these lesions are discovered four to six weeks after injuries. More frequently, Achilles tendon ruptures are acute and treated with tendon sutures.1 Many surgical techniques are available to treat chronic lesions such as sutures or V-Y elongation with or without augments.2-3 Our case is about a chronic Achilles tendon rupture discovered two years after injury. Our patient came to our attention with a 6 cm tendon gap. We performed tendon repair with cadaver allograft. After four years of follow-up, our patient has a complete functional recovery and he can normally perform daily and working tasks without pain.

  15. Tendon fascicles exhibit a linear correlation between Poisson's ratio and force during uniaxial stress relaxation.

    PubMed

    Reese, Shawn P; Weiss, Jeffrey A

    2013-03-01

    The underlying mechanisms for the viscoelastic behavior of tendon and ligament tissue are poorly understood. It has been suggested that both a flow-dependent and flow-independent mechanism may contribute at different structural levels. We hypothesized that the stress relaxation response of a single tendon fascicle is consistent with the flow-dependent mechanism described by the biphasic theory (Armstrong et al., 1984, "An Analysis of the Unconfined Compression of Articular Cartilage," ASME J. Biomech. Eng., 106, pp. 165-173). To test this hypothesis, force, lateral strain, and Poisson's ratio were measured as a function of time during stress relaxation testing of six rat tail tendon fascicles from a Sprague Dawley rat. As predicted by biphasic theory, the lateral strain and Poisson's ratio were time dependent, a large estimated volume loss was seen at equilibrium and there was a linear correlation between the force and Poisson's ratio during stress relaxation. These results suggest that the fluid dependent mechanism described by biphasic theory may explain some or all of the apparent viscoelastic behavior of single tendon fascicles.

  16. Comparative biochemical analysis of sea urchin peristome and rat tail tendon collagen.

    PubMed

    Robinson, J J

    1997-06-01

    We report here a biochemical comparison between type 1 rat tail tendon collagen and collagen isolated from sea urchin peristome tissue. The sea urchin collagen consisted of two species of apparent mol masses, 140 and 116 kDa. Amino acid compositional analysis of the 140 and 116 kDa species revealed the presence of hydroxyproline and hydroxylysine as well as a glycine content of 28.1 mol.%. In solubility experiments the rat tail tendon collagen was found to precipitate at sodium chloride concentrations between 1 and 2 M while peristome collagen remained soluble at salt concentrations as high as 4 M. Incubation of the peristome and rat tail tendon collagen preparations with a sea urchin collagenase/gelatinase resulted in cleavage of the former but not the latter collagen. Upon heat denaturation at 60 degrees C, however, the rat tail tendon collagen served as a substrate for the gelatinase. Cyanogen bromide cleavage of rat tail and peristome collagens generated largely unique peptide maps. Collectively, these results suggest that structural differences exist between echinoderm and vertebrate type 1 collagens.

  17. Development of a mouse model of supraspinatus tendon insertion site healing.

    PubMed

    Bell, Rebecca; Taub, Peter; Cagle, Paul; Flatow, Evan L; Andarawis-Puri, Nelly

    2015-01-01

    Supraspinatus (SS) tendon tears are common musculoskeletal injuries whose surgical repair exhibits the highest incidence of re-tear of any tendon. Development of therapeutics for improving SS tendon healing is impaired by the lack of a model that allows biological perturbations to identify mechanisms that underlie ineffective healing. The objective of this study was to develop a mouse model of supraspinatus insertion site healing by creating a reproducible SS tendon detachment and surgical repair which can be applied to a wide array of inbred mouse strains and genetic mutants. Anatomical and structural analyses confirmed that the rotator cuff of the mouse is similar to that of human, including the presence of a coracoacromial (CA) arch and an insertion site that exhibits a fibrocartilagenous transition zone. The surgical repair was successfully conducted on seven strains of mice that are commonly used in Orthopaedic Research suggesting that the procedure can be applied to most inbred strains and genetic mutants. The quality of the repair was confirmed with histology through 14 days after surgery in two mouse strains that represent the variation in mouse strains evaluated. The developed mouse model will allow us to investigate mechanisms involved in insertion site healing.

  18. The role of the biceps tendon in massive rotator cuff tears.

    PubMed

    Pill, Stephan G; Walch, Gilles; Hawkins, Richard J; Kissenberth, Michael J

    2012-01-01

    Tendinopathy of the long head of the biceps (LHB) tendon commonly occurs in patients with rotator cuff tears, and the inflammation of one head tends to lead to inflammation of the other. Many theories have been proposed regarding the function of the LHB tendon; however, its exact purpose is poorly understood. It has been described as an important stabilizer of the glenohumeral joint, a depressor of the humeral head, and as a vestigial structure. The LHB tendon can be a significant source of pain in patients with rotator cuff tears. The appropriate treatment depends on the patient's age, comorbidities, activity level, extent of disability, the presence of rotator cuff arthropathy, and the quality of the rotator cuff tissue. Conservative treatment is usually attempted first, with modalities such as nonsteroidal anti-inflammatory drugs, corticosteroid injections, physical therapy, and activity modification. If symptoms persist, biceps tenotomy or tenodesis may be combined with rotator cuff repair, depending on the quality of the rotator cuff tissue, the severity of rotator cuff arthropathy, and the willingness of the patient to comply with postoperative immobilization and rehabilitation. Even when rotator cuff repair is not possible, isolated tenotomy or tenodesis of the LHB tendon can provide substantial pain relief.

  19. Surgical Management of Fractures and Tendons.

    PubMed

    Pentecost, Rebecca; Niehaus, Andrew J; Anderson, David E

    2016-11-01

    Long bone fractures and disorders of tendons and ligaments represent a significant proportion of surgical orthopedic cases presented to ruminant veterinarians. The presentation of these patients, their diagnostic work-up, surgical treatment, and expected outcome will be discussed. The outcome of these cases depends largely on the presenting problem; however, accurate diagnosis and prompt surgical intervention can greatly improve the outcome of many of these cases.

  20. Rat Achilles tendon healing: mechanical loading and gene expression.

    PubMed

    Eliasson, Pernilla; Andersson, Therese; Aspenberg, Per

    2009-08-01

    Injured tendons require mechanical tension for optimal healing, but it is unclear which genes are upregulated and responsible for this effect. We unloaded one Achilles tendon in rats by Botox injections in the calf muscles. The tendon was then transected and left to heal. We studied mechanical properties of the tendon calluses, as well as mRNA expression, and compared them with loaded controls. Tendon calluses were studied 3, 8, 14, and 21 days after transection. Intact tendons were studied similarly for comparison. Altogether 110 rats were used. The genes were chosen for proteins marking inflammation, growth, extracellular matrix, and tendon specificity. In intact tendons, procollagen III and tenascin-C were more expressed in loaded than unloaded tendons, but none of the other genes was affected. In healing tendons, loading status had small effects on the selected genes. However, TNF-alpha, transforming growth factor-beta1, and procollagens I and III were less expressed in loaded callus tissue at day 3. At day 8 procollagens I and III, lysyl oxidase, and scleraxis had a lower expression in loaded calluses. However, by days 14 and 21, procollagen I, cartilage oligomeric matrix protein, tenascin-C, tenomodulin, and scleraxis were all more expressed in loaded calluses. In healing tendons, the transverse area was larger in loaded samples, but material properties were unaffected, or even impaired. Thus mechanical loading is important for growth of the callus but not its mechanical quality. The main effect of loading during healing might thereby be sought among growth stimulators. In the late phase of healing, tendon-specific genes (scleraxis and tenomodulin) were upregulated with loading, and the healing tissue might to some extent represent a regenerate rather than a scar.

  1. Tendon biomechanical properties enhance human wrist muscle specialization.

    PubMed

    Loren, G J; Lieber, R L

    1995-07-01

    Biomechanical properties of human wrist tendons were measured under loads predicted to be experienced by those tendons under physiological conditions. This was accomplished by measuring the architectural properties of the five prime wrist movers--extensors carpi radialis brevis (ECRB), extensor carpi radialis longus (ECRL), extensor carpi ulnaris (ECU), flexor carpi radials (FCR), flexor carpi ulnaris (FCU)--and predicting their maximum tension (P0) using a specific tension value (22.5 N cm-2. Loading the corresponding tendons to P0 resulted in significantly different strain among tendons (p < 0.01) with the largest strain observed in the FCU (3.68 +/- 0.31%) and the smallest strain observed in the ECRL (1.78 +/- 0.14%). Further, strain magnitude was significantly positively correlated with the tendon length-to-fiber length ratio of the muscle-tendon unit, a measure of the intrinsic compliance of the muscle-tendon unit. Theoretical modeling of the magnitude of muscle sarcomere shortening expected based on the measured biomechanical properties revealed a maximum sarcomere length decrease of about 0.6 micron for the FCU to a minimum of about 0.2 micron for the ECRB at P0. Thus, tendon compliance may, but does not necessarily, result in significant modification of muscle force generation. The significant variation in tendon biomechanical properties was not observed using traditional elongation-to-failure methods on the same specimens. Thus, the use of elongation-to-failure experiments for determination of tendon properties may not be reasonable when the purpose of such studies is to infer physiological function. These data indicate that muscle-tendon units show remarkable specialization and that tendon intrinsic properties accentuate the muscle architectural specialization already present.

  2. Extensor tendon ruptures after total knee arthroplasty.

    PubMed

    Bonnin, M; Lustig, S; Huten, D

    2016-02-01

    Extensor tendon rupture is a rare but serious complication after total knee arthroplasty (TKA) that impairs active knee extension, thereby severely affecting knee function. Surgery is usually required. Surgical options range from simple suturing to allograft reconstruction of the entire extensor mechanism and include intermediate methods such as reconstruction using neighbouring tendons or muscles, synthetic ligament implantation, and partial allograft repair. Simple suturing carries a high failure rate and should therefore be routinely combined with tissue augmentation using a neighbouring tendon or a synthetic ligament. After allograft reconstruction, outcomes are variable and long-term complications common. Salvage procedures for managing the most severe cases after allograft failure involve reconstruction using gastrocnemius or vastus flaps. Regardless of the technique used, suturing must be performed under tension, with the knee fully extended, and rehabilitation must be conducted with great caution. Weaknesses of available case-series studies include small sample sizes, heterogeneity, and inadequate follow-up duration. All treatment options are associated with substantial failure rates. The patient should be informed of this fact and plans made for a salvage option. Here, the main techniques and their outcomes are discussed, and a therapeutic strategy is suggested.

  3. Low level laser therapy in healing tendon

    NASA Astrophysics Data System (ADS)

    Carvalho, P. T. C.; Batista, Cheila O. C.; Fabíola, C.

    2005-11-01

    This study aims to verify the effects of AsGa Laser in the scarring of tendon lesion in rats with low nourishment condition and to analyze the ideal light density by means of histopathologic findings highlighted by light microscopy. After the proposed nutritional condition was verified the animals were divided into 3 groups denominated as follows: GI control group, GII laser 1 J/sq.cm. and GIII laser 4 J/sq.cm. The lesions were induced by means of routine surgical process for tendon exposure: There was a crushing process with Allis pincers followed by saturated incision. The data obtained in relation to the amount of macrophage, leukocyte, fibroblast, vessel neoformation, fibrosis and collagen were submitted to parametric statistic procedures of variance analysis and "Tukey" Test and the result obtained was p < 0,05. According to the obtained results it can be concluded that low power laser therapy proved to be efficient in tendon repairing even though the animals suffered from malnutrition as well as the 1 J energy density proved to be more efficient in this case.

  4. Retropharyngeal calcific tendonitis: report of two cases.

    PubMed

    Razon, Rhea Victoria B; Nasir, Asad; Wu, George S; Soliman, Manal; Trilling, Jeffrey

    2009-01-01

    Retropharyngeal calcific tendonitis is an inflammatory process of the superior oblique tendons of the longus colli muscle, a neck flexor in the upper cervical spine, caused by deposition of calcium hydroxyapatite crystals; the definitive diagnostic test is computed tomography (CT). Presented in this article are two cases seen at our institution. Patients typically present with acute onset of neck pain/spasm, odynophagia, dysphagia, and/or low grade fevers. Leukocytosis and elevated erythrocyte sedimentation rate may be noted. It is important to understand this entity because its signs and symptoms are mimickers of those of the more serious condition of retropharyngeal space abscess. Calcific tendonitis is managed conservatively whereas retropharyngeal abscess requires incision and drainage. Some may argue that this entity is a zebra because its reported incidence in the literature is low. However, most of these studies were done in an era when CT was not yet in vogue. With today's widespread use of CT and its superb ability to visualize the calcification, the true incidence of this condition is probably higher and, thus, it is important for the family practitioner to be aware of this entity. The astute clinician may save the patient from unnecessary diagnostic workup, undue anxiety, and delays in hospital discharge.

  5. An Artificial Tendon with Durable Muscle Interface

    PubMed Central

    Melvin, Alan; Litsky, Alan; Mayerson, Joel; Witte, David; Melvin, David; Juncosa-Melvin, Natalia

    2010-01-01

    A coupling mechanism that can permanently fix a forcefully contracting muscle to a bone anchor or any totally inert prosthesis would meet a serious need in orthopaedics. Our group developed the OrthoCoupler™ device to satisfy these demands. The objective of this study was to test OrthoCoupler’s performance in vitro and in vivo in the goat semitendinosus tendon model. For in vitro evaluation, 40 samples were fatigue-tested, cycling at 10 load levels, n=4 each. For in vivo evaluation, the semitendinosus tendon was removed bilaterally in 8 goats. Left sides were reattached with an OrthoCoupler, and right sides were reattached using the Krackow stitch with #5 braided polyester sutures. Specimens were harvested 60 days post-surgery and assigned for biomechanics and histology. Fatigue strength of the devices in vitro was several times the contractile force of the semitendinosus muscle. The in vivo devices were built equivalent to two of the in vitro devices, providing an additional safety factor. In strength testing at necropsy, suture controls pulled out at 120.5 ± 68.3 N, whereas each OrthoCoupler was still holding after the muscle tore, remotely, at 298±111.3N (mean ± SD)(p<0.0003). Muscle tear strength was reached with the fiber-muscle composite produced in healing still soundly intact. This technology may be of value for orthopaedic challenges in oncology, revision arthroplasty, tendon transfer, and sports-injury reconstruction. PMID:19639642

  6. Use of the semitendinosus tendon for foot and ankle tendon reconstructions☆☆☆

    PubMed Central

    Lutti Guerra de Aguiar Zink, Frederico; Glória Mendonça, Danilo; Kelly Bittar, Cintia; Luís Amim Zabeu, José; Salomão, Osny; Egydio de Carvalho Junior, Antonio; Tarso Torquato, Marcelo; Cerqueira de Moraes Filho, Décio

    2014-01-01

    Objective To demonstrate the results obtained from foot and ankle tendon reconstructions using the tendon of the semitendinosus muscle. The clinical results, the patient's degree of satisfaction and complications in the graft donor and recipient areas were evaluated. Methods This was a retrospective study in which the medical files of 38 patients who underwent this surgical procedure between 2006 and 2010 were surveyed. The functional results from this technique, the complications in the donor and recipient areas and the patients’ degree of satisfaction were evaluated. Results Three patients presented complications in the recipient area (skin necrosis); one patient showed complications in the donor area (pain and insensitivity); and all patients had satisfactory functional results, with complete range of motion. Conclusion The semitendinosus muscle is a good option for treatments for foot and ankle tendon injuries. PMID:26229856

  7. Nanoparticles for Tendon Healing and Regeneration: Literature Review

    PubMed Central

    Parchi, Paolo D.; Vittorio, Orazio; Andreani, Lorenzo; Battistini, Pietro; Piolanti, Nicola; Marchetti, Stefano; Poggetti, Andrea; Lisanti, Michele

    2016-01-01

    Tendon injuries are commonly met in the emergency department. Unfortunately, tendon tissue has limited regeneration potential and usually the consequent formation of scar tissue causes inferior mechanical properties. Nanoparticles could be used in different way to improve tendon healing and regeneration, ranging from scaffolds manufacturing (increasing the strength and endurance or anti-adhesions, anti-microbial, and anti-inflammatory properties) to gene therapy. This paper aims to summarize the most relevant studies showing the potential application of nanoparticles for tendon tissue regeneration. PMID:27597828

  8. 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

  9. Compression therapy promotes proliferative repair during rat Achilles tendon immobilization.

    PubMed

    Schizas, Nikos; Li, Jian; Andersson, Therese; Fahlgren, Anna; Aspenberg, Per; Ahmed, Mahmood; Ackermann, Paul W

    2010-07-01

    Achilles tendon ruptures are treated with an initial period of immobilization, which obstructs the healing process partly by a reduction of blood circulation. Intermittent pneumatic compression (IPC) has been proposed to enhance tendon repair by stimulation of blood flow. We hypothesized that daily IPC treatment can counteract the deficits caused by 2 weeks of immobilization post tendon rupture. Forty-eight Sprague-Dawley SD) rats, all subjected to blunt Achilles tendon transection, were divided in three equal groups. Group A was allowed free cage activity, whereas groups B-C were immobilized at the operated hindleg. Group C received daily IPC treatment. Two weeks postrupture the rats were euthanatized and the tendons analyzed with tensile testing and histological assessments of collagen organization and collagen III-LI occurrence. Immobilization significantly reduced maximum force, energy uptake, stiffness, tendon length, transverse area, stress, organized collagen diameter and collagen III-LI occurrence by respectively 80, 75, 77, 22, 47, 65, 49, and 83% compared to free mobilization. IPC treatment improved maximum force 65%, energy 168%, organized collagen diameter 50%, tendon length 25%, and collagen III-LI occurrence 150% compared to immobilization only. The results confirm that immobilization impairs healing after tendon rupture and furthermore demonstrate that IPC-treatment can enhance proliferative tendon repair by counteracting biomechanical and morphological deficits caused by immobilization.

  10. Engineering Tendon: Scaffolds, Bioreactors, and Models of Regeneration

    PubMed Central

    Youngstrom, Daniel W.; Barrett, Jennifer G.

    2016-01-01

    Tendons bridge muscle and bone, translating forces to the skeleton and increasing the safety and efficiency of locomotion. When tendons fail or degenerate, there are no effective pharmacological interventions. The lack of available options to treat damaged tendons has created a need to better understand and improve the repair process, particularly when suitable autologous donor tissue is unavailable for transplantation. Cells within tendon dynamically react to loading conditions and undergo phenotypic changes in response to mechanobiological stimuli. Tenocytes respond to ultrastructural topography and mechanical deformation via a complex set of behaviors involving force-sensitive membrane receptor activity, changes in cytoskeletal contractility, and transcriptional regulation. Effective ex vivo model systems are needed to emulate the native environment of a tissue and to translate cell-matrix forces with high fidelity. While early bioreactor designs have greatly expanded our knowledge of mechanotransduction, traditional scaffolds do not fully model the topography, composition, and mechanical properties of native tendon. Decellularized tendon is an ideal scaffold for cultivating replacement tissue and modeling tendon regeneration. Decellularized tendon scaffolds (DTS) possess high clinical relevance, faithfully translate forces to the cellular scale, and have bulk material properties that match natural tissue. This review summarizes progress in tendon tissue engineering, with a focus on DTS and bioreactor systems. PMID:26839559

  11. Inflammation activation and resolution in human tendon disease

    PubMed Central

    Dakin, Stephanie G; Martinez, Fernando O; Yapp, Clarence; Wells, Graham; Oppermann, Udo; Dean, Benjamin JF; Smith, Richard DJ; Wheway, Kim; Watkins, Bridget; Roche, Lucy; Carr, Andrew J

    2016-01-01

    Improved understanding of the role of inflammation in tendon disease is required to facilitate therapeutic target discovery. We studied supraspinatus tendons from patients experiencing pain before and after surgical subacromial decompression treatment. Tendons were classified as having early, intermediate or advanced disease and inflammation was characterized through activation of pathways mediated by Interferon, NF-κB, glucocorticoid receptor and STAT-6. Inflammation signatures revealed expression of genes and proteins induced by Interferon and NF-κB in early stage disease and genes and proteins induced by STAT-6 and glucocorticoid receptor activation in advanced stage disease. The pro-resolving proteins FPR2/ALX and ChemR23 were increased in early stage disease compared to intermediate-advanced stage disease. Patients who were pain-free post-treatment had tendons with increased expression of CD206 and ALOX15 mRNA compared to tendons from patients who continued to experience pain post-treatment, suggesting that these genes and their pathways may moderate tendon pain. Stromal cells from diseased tendons cultured in vitro showed increased expression of NF-κB and Interferon target genes after treatment with lipopolysaccharide or IFNγ compared to stromal cells derived from healthy tendons. We identified 15-epi Lipoxin A4, a stable lipoxin metabolite derived from aspirin treatment, as potentially beneficial in the resolution of tendon inflammation. PMID:26511510

  12. Endoscopic Resection of the Tibialis Anterior Tendon Bursa.

    PubMed

    Lui, Tun Hing

    2016-10-01

    The tibialis anterior tendon bursa is located between the tibialis anterior tendon and the medial cuneiform bone and close to the tendon insertion. Bursitis can occur as a result of excessive local friction, infection, arthritides, or direct trauma. Endoscopic resection of the bursa is indicated in case of symptomatic bursitis that is not responding to conservative treatment or infection is suspected. It is contraindicated if there is skin infection at the portal sites. The purpose of this technical note is to describe a minimally invasive approach of endoscopic resection of the tibialis anterior tendon bursa through anterior tibial tendoscopy.

  13. Reconstruction and restoration of neglected ruptured patellar tendon using semitendinosus and gracilis tendons with preserved distal insertions: two case reports.

    PubMed

    Chen, Bin; Li, Runguang; Zhang, Sheng

    2012-08-01

    Neglected rupture of the patellar tendon is rare but becomes more difficult to repair the longer it is left untreated. The most common rupture sites are the inferior pole of the patella and distal insertion. Proximal retraction of the patella and extensor mechanism adhesions makes the treatment more difficult than acute tendon rupture. We report two patients with neglected patellar tendon rupture treated by reconstruction and restoration using semitendinosus-gracilis (STG) tendons with preserved distal insertions. Preserved distal insertion provided sufficient blood supply to accelerate healing, while combined fixation with tension-reducing wire, offered the initial stability of the closed-loop sutured tendon. Both patients reacquired near normal strength and stability of the patellar tendon and restoration of function after operation and rehabilitation.

  14. Multilayered Electrospun Scaffolds for Tendon Tissue Engineering

    PubMed Central

    Chainani, Abby; Hippensteel, Kirk J.; Kishan, Alysha; Garrigues, N. William; Ruch, David S.; Guilak, Farshid

    2013-01-01

    Full-thickness rotator cuff tears are one of the most common causes of shoulder pain in people over the age of 65. High retear rates and poor functional outcomes are common after surgical repair, and currently available extracellular matrix scaffold patches have limited abilities to enhance new tendon formation. In this regard, tissue-engineered scaffolds may provide a means to improve repair of rotator cuff tears. Electrospinning provides a versatile method for creating nanofibrous scaffolds with controlled architectures, but several challenges remain in its application to tissue engineering, such as cell infiltration through the full thickness of the scaffold as well as control of cell growth and differentiation. Previous studies have shown that ligament-derived extracellular matrix may enhance differentiation toward a tendon or ligament phenotype by human adipose stem cells (hASCs). In this study, we investigated the use of tendon-derived extracellular matrix (TDM)-coated electrospun multilayered scaffolds compared to fibronectin (FN) or phosphate-buffered saline (PBS) coating for use in rotator cuff tendon tissue engineering. Multilayered poly(ɛ-caprolactone) scaffolds were prepared by sequentially collecting electrospun layers onto the surface of a grounded saline solution into a single scaffold. Scaffolds were then coated with TDM, FN, or PBS and seeded with hASCs. Scaffolds were maintained without exogenous growth factors for 28 days in culture and evaluated for protein content (by immunofluorescence and biochemical assay), markers of tendon differentiation, and tensile mechanical properties. The collagen content was greatest by day 28 in TDM-scaffolds. Gene expression of type I collagen, decorin, and tenascin C increased over time, with no effect of scaffold coating. Sulfated glycosaminoglycan and dsDNA contents increased over time in culture, but there was no effect of scaffold coating. The Young's modulus did not change over time, but yield strain

  15. 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.

  16. Tendon progenitor cells in injured tendons have strong chondrogenic potential: the CD105-negative subpopulation induces chondrogenic degeneration.

    PubMed

    Asai, Shuji; Otsuru, Satoru; Candela, Maria Elena; Cantley, Leslie; Uchibe, Kenta; Hofmann, Ted J; Zhang, Kairui; Wapner, Keith L; Soslowsky, Louis J; Horwitz, Edwin M; Enomoto-Iwamoto, Motomi

    2014-12-01

    To study the cellular mechanism of the tendon repair process, we used a mouse Achilles tendon injury model to focus on the cells recruited to the injured site. The cells isolated from injured tendon 1 week after the surgery and uninjured tendons contained the connective tissue progenitor populations as determined by colony-forming capacity, cell surface markers, and multipotency. When the injured tendon-derived progenitor cells (inTPCs) were transplanted into injured Achilles tendons, they were not only integrated in the regenerating area expressing tenogenic phenotype but also trans-differentiated into chondrogenic cells in the degenerative lesion that underwent ectopic endochondral ossification. Surprisingly, the micromass culture of the inTPCs rapidly underwent chondrogenic differentiation even in the absence of exogenous bone morphogenetic proteins or TGFβs. The cells isolated from human ruptured tendon tissues also showed connective tissue progenitor properties and exhibited stronger chondrogenic ability than bone marrow stromal cells. The mouse inTPCs contained two subpopulations one positive and one negative for CD105, a coreceptor of the TGFβ superfamily. The CD105-negative cells showed superior chondrogenic potential in vitro and induced larger chondroid degenerative lesions in mice as compared to the CD105-positive cells. These findings indicate that tendon progenitor cells are recruited to the injured site of tendons and have a strong chondrogenic potential and that the CD105-negative population of these cells would be the cause for chondroid degeneration in injured tendons. The newly identified cells recruited to the injured tendon may provide novel targets to develop therapeutic strategies to facilitate tendon repair.

  17. In vivo passive mechanical behaviour of muscle fascicles and tendons in human gastrocnemius muscle-tendon units.

    PubMed

    Herbert, Robert D; Clarke, Jillian; Kwah, Li Khim; Diong, Joanna; Martin, Josh; Clarke, Elizabeth C; Bilston, Lynne E; Gandevia, Simon C

    2011-11-01

    Ultrasound imaging was used to measure the length of muscle fascicles in human gastrocnemius muscles while the muscle was passively lengthened and shortened by moving the ankle. In some subjects the muscle belly 'buckled' at short lengths. When the gastrocnemius muscle-tendon unit was passively lengthened from its shortest in vivo length by dorsiflexing the ankle, increases in muscle-tendon length were not initially accompanied by increases in muscle fascicle lengths (fascicle length remained constant), indicating muscle fascicles were slack at short muscle-tendon lengths. The muscle-tendon length at which slack is taken up differs among fascicles: some fascicles begin to lengthen at very short muscle-tendon lengths whereas other fascicles remain slack over a large range of muscle-tendon lengths. This suggests muscle fascicles are progressively 'recruited' and contribute sequentially to muscle-tendon stiffness during passive lengthening of the muscle-tendon unit. Even above their slack lengths muscle fascicles contribute only a small part (<~30%) of the total change in muscle-tendon length. The contribution of muscle fascicles to muscle-tendon length increases with muscle length. The novelty of this work is that it reveals a previously unrecognised phenomenon (buckling at short lengths), posits a new mechanism of passive mechanical properties of muscle (recruitment of muscle fascicles), and confirms with high-resolution measurements that the passive compliance of human gastrocnemius muscle-tendon units is due largely to the tendon. It would be interesting to investigate if adaptations of passive properties of muscles are associated with changes in the distribution of muscle lengths at which fascicles fall slack.

  18. Endoscopic Resection of Gouty Tophus of the Patellar Tendon.

    PubMed

    Lui, Tun Hing

    2015-08-01

    Tophaceous deposition of tendon can result in spontaneous patellar tendon rupture. Surgical therapy may be needed to control symptoms and prevent tendon rupture. Open debridement of the lesion requires a lengthy incision over the lesion; this may result in symptomatic scar adhesion of the patellar tendon or an unhealed wound with persistent tophaceous discharge. Moreover, the other part of the patellar tendon cannot be examined through the incision. We describe a technique for endoscopic resection of a gouty tophus of the patellar tendon. It has the advantage of small incisions away from the lesion and tendon and minimizes wound problems. The whole patellar tendon can be examined endoscopically.

  19. Reconstruction of chronic patellar tendon rupture using graft from contralateral patella graft together with reinforcement from flexor tendons. Case report.

    PubMed

    Frois Temponi, Eduardo; de Carvalho, Lúcio Honório; da Silva Bernardes, Cláudio Otávio; Presses Teixeira, Bruno

    2016-01-01

    Chronic patellar tendon rupture is a rare disabling injury that is technically difficult to repair. The true prevalence of this injury is unknown. Delayed reconstruction of chronic patellar tendon rupture has yielded suboptimal clinical and functional results. Many different surgical methods for reconstruction of chronic patellar tendon injury have been reported. In this report, we present a case with chronic patellar tendon injury that was addressed using a technique that had not previously been described in the literature, through combining procedures that had been described separately. The reconstruction method presented in this article has the advantages of being easy and reproducible, without a requirement of allografts.

  20. 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.

  1. 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

  2. Floating patella: combined quadriceps tendon, retinacula, and patellar tendon ruptures in a high-performance elite athlete.

    PubMed

    Langer, Phillip R; Selesnick, F Harlan

    2010-09-01

    Simultaneous quadriceps and patellar tendon rupture is rare. To our knowledge, we present the first known case of simultaneous quadriceps tendon, patella tendon, and retinacula rupture in the ipsilateral knee of a high-performance elite athlete. This disabling injury in the active person results in an inability to actively obtain and maintain full knee extension. When the tendons do not heal properly, at the correct length and tension, knee range of motion and strength can become significantly altered, leading to early fatigue, patellofemoral pain, and possibly instability, preventing return to preinjury status. Immediate surgical repair is recommended for optimal return of knee function and power.

  3. The development of zebrafish tendon and ligament progenitors.

    PubMed

    Chen, Jessica W; Galloway, Jenna L

    2014-05-01

    Despite the importance of tendons and ligaments for transmitting movement and providing stability to the musculoskeletal system, their development is considerably less well understood than that of the tissues they serve to connect. Zebrafish have been widely used to address questions in muscle and skeletal development, yet few studies describe their tendon and ligament tissues. We have analyzed in zebrafish the expression of several genes known to be enriched in mammalian tendons and ligaments, including scleraxis (scx), collagen 1a2 (col1a2) and tenomodulin (tnmd), or in the tendon-like myosepta of the zebrafish (xirp2a). Co-expression studies with muscle and cartilage markers demonstrate the presence of scxa, col1a2 and tnmd at sites between the developing muscle and cartilage, and xirp2a at the myotendinous junctions. We determined that the zebrafish craniofacial tendon and ligament progenitors are neural crest derived, as in mammals. Cranial and fin tendon progenitors can be induced in the absence of differentiated muscle or cartilage, although neighboring muscle and cartilage are required for tendon cell maintenance and organization, respectively. By contrast, myoseptal scxa expression requires muscle for its initiation. Together, these data suggest a conserved role for muscle in tendon development. Based on the similarities in gene expression, morphology, collagen ultrastructural arrangement and developmental regulation with that of mammalian tendons, we conclude that the zebrafish tendon populations are homologous to their force-transmitting counterparts in higher vertebrates. Within this context, the zebrafish model can be used to provide new avenues for studying tendon biology in a vertebrate genetic system.

  4. Fabrication and Pilot In Vivo Study of a Collagen-BDDGE-Elastin Core-Shell Scaffold for Tendon Regeneration.

    PubMed

    Sandri, Monica; Filardo, Giuseppe; Kon, Elizaveta; Panseri, Silvia; Montesi, Monica; Iafisco, Michele; Savini, Elisa; Sprio, Simone; Cunha, Carla; Giavaresi, Gianluca; Veronesi, Francesca; Fini, Milena; Salvatore, Luca; Sannino, Alessandro; Marcacci, Maurilio; Tampieri, Anna

    2016-01-01

    The development of bio-devices for complete regeneration of ligament and tendon tissues is presently one of the biggest challenges in tissue engineering. Such device must simultaneously possess optimal mechanical performance, suitable porous structure, and biocompatible microenvironment. This study proposes a novel collagen-BDDGE-elastin (CBE)-based device for tendon tissue engineering, by the combination of two different modules: (i) a load-bearing, non-porous, "core scaffold" developed by braiding CBE membranes fabricated via an evaporative process and (ii) a hollow, highly porous, "shell scaffold" obtained by uniaxial freezing followed by freeze-drying of CBE suspension, designed to function as a physical guide and reservoir of cells to promote the regenerative process. Both core and shell materials demonstrated good cytocompatibility in vitro, and notably, the porous shell architecture directed cell alignment and population within the sample. Finally, a prototype of the core module was implanted in a rat tendon lesion model, and histological analysis demonstrated its safety, biocompatibility, and ability to induce tendon regeneration. Overall, our results indicate that such device may have the potential to support and induce in situ tendon regeneration.

  5. Fabrication and Pilot In Vivo Study of a Collagen-BDDGE-Elastin Core-Shell Scaffold for Tendon Regeneration

    PubMed Central

    Sandri, Monica; Filardo, Giuseppe; Kon, Elizaveta; Panseri, Silvia; Montesi, Monica; Iafisco, Michele; Savini, Elisa; Sprio, Simone; Cunha, Carla; Giavaresi, Gianluca; Veronesi, Francesca; Fini, Milena; Salvatore, Luca; Sannino, Alessandro; Marcacci, Maurilio; Tampieri, Anna

    2016-01-01

    The development of bio-devices for complete regeneration of ligament and tendon tissues is presently one of the biggest challenges in tissue engineering. Such device must simultaneously possess optimal mechanical performance, suitable porous structure, and biocompatible microenvironment. This study proposes a novel collagen-BDDGE-elastin (CBE)-based device for tendon tissue engineering, by the combination of two different modules: (i) a load-bearing, non-porous, “core scaffold” developed by braiding CBE membranes fabricated via an evaporative process and (ii) a hollow, highly porous, “shell scaffold” obtained by uniaxial freezing followed by freeze-drying of CBE suspension, designed to function as a physical guide and reservoir of cells to promote the regenerative process. Both core and shell materials demonstrated good cytocompatibility in vitro, and notably, the porous shell architecture directed cell alignment and population within the sample. Finally, a prototype of the core module was implanted in a rat tendon lesion model, and histological analysis demonstrated its safety, biocompatibility, and ability to induce tendon regeneration. Overall, our results indicate that such device may have the potential to support and induce in situ tendon regeneration. PMID:27446909

  6. Regeneration and repair of tendon and ligament tissue using collagen fibre biomaterials.

    PubMed

    Kew, S J; Gwynne, J H; Enea, D; Abu-Rub, M; Pandit, A; Zeugolis, D; Brooks, R A; Rushton, N; Best, S M; Cameron, R E

    2011-09-01

    Collagen fibres are ubiquitous macromolecular assemblies in nature, providing the structures that support tensile mechanical loads within the human body. Aligned type I collagen fibres are the primary structural motif for tendon and ligament, and therefore biomaterials based on these structures are considered promising candidates for mediating regeneration of these tissues. However, despite considerable investigation, there remains no collagen-fibre-based biomaterial that has undergone clinical evaluation for this application. Recent research in this area has significantly enhanced our understanding of these complex and challenging biomaterials, and is reinvigorating interest in the development of such structures to recapitulate mechanical function. In this review we describe the progress to date towards a ligament or tendon regeneration template based on collagen fibre scaffolds. We highlight reports of particular relevance to the development of the underlying biomaterials science in this area. In addition, the potential for tailoring and manipulating the interactions between collagen fibres and biological systems, as hybrid biomaterial-biological ensembles, is discussed in the context of developing novel tissue engineering strategies for tendon and ligament.

  7. In situ multi-level analysis of viscoelastic deformation mechanisms in tendon collagen.

    PubMed

    Gupta, H S; Seto, J; Krauss, S; Boesecke, P; Screen, H R C

    2010-02-01

    Tendon is a hydrated multi-level fibre composite, in which time-dependent behaviour is well established. Studies indicate significant stress relaxation, considered important for optimising tissue stiffness. However, whilst this behaviour is well documented, the mechanisms associated with the response are largely unknown. This study investigates the sub-structural mechanisms occurring during stress relaxation at both the macro (fibre) and nano (fibril) levels of the tendon hierarchy. Stress relaxation followed a two-stage exponential behaviour, during which structural changes were visible at the fibre and fibril levels. Fibril relaxation and fibre sliding showed a double exponential response, while fibre sliding was clearly the largest contributor to relaxation. The amount of stress relaxation and sub-structural reorganisation increased with increasing load increments, but fibre sliding was consistently the largest contributor to stress relaxation. A simple model of tendon viscoelasticity at the fibril and fibre levels has been developed, capturing this behaviour by serially coupling a Voigt element (collagen fibril), with two Maxwell elements (non-collagenous matrix between fibrils and fibres). This multi-level analysis provides a first step towards understanding how sub-structural interactions contribute to viscoelastic behaviour. It indicates that nano- and micro-scale shearing are significant dissipative mechanisms, and the kinetics of relaxation follows a two-stage exponential decay, well fitted by serially coupled viscoelastic elements.

  8. EGR1 Regulates Transcription Downstream of Mechanical Signals during Tendon Formation and Healing

    PubMed Central

    Delalande, Antony; Bonnin, Marie-Ange; Pichon, Chantal

    2016-01-01

    Background Tendon is a mechanical tissue that transmits forces generated by muscle to bone in order to allow body motion. The molecular pathways that sense mechanical forces during tendon formation, homeostasis and repair are not known. EGR1 is a mechanosensitive transcription factor involved in tendon formation, homeostasis and repair. We hypothesized that EGR1 senses mechanical signals to promote tendon gene expression. Methodology/Principal findings Using in vitro and in vivo models, we show that the expression of Egr1 and tendon genes is downregulated in 3D-engineered tendons made of mesenchymal stem cells when tension is released as well as in tendon homeostasis and healing when mechanical signals are reduced. We further demonstrate that EGR1 overexpression prevents tendon gene downregulation in 3D-engineered tendons when tension is released. Lastly, ultrasound and microbubbles mediated EGR1 overexpression prevents the downregulation of tendon gene expression during tendon healing in reduced load conditions. Conclusion/Significance These results show that Egr1 expression is sensitive to mechanical signals in tendon cells. Moreover, EGR1 overexpression prevents the downregulation of tendon gene expression in the absence of mechanical signals in 3D-engineered tendons and tendon healing. These results show that EGR1 induces a transcriptional response downstream of mechanical signals in tendon cells and open new avenues to use EGR1 to promote tendon healing in reduced load conditions. PMID:27820865

  9. Achilles tendon biomechanics in response to acute intense exercise.

    PubMed

    Joseph, Michael F; Lillie, Kurtis R; Bergeron, Daniel J; Cota, Kevin C; Yoon, Joseph S; Kraemer, William J; Denegar, Craig R

    2014-05-01

    Achilles tendinopathy is a common disorder and is more prevalent in men. Although differences in tendon mechanics between men and women have been reported, understanding of tendon mechanics in young active people is limited. Moreover, there is limited understanding of changes in tendon mechanics in response to acute exercise. Our purpose was to compare Achilles tendon mechanics in active young adult men and women at rest and after light and strenuous activity in the form of repeated jumping with an added load. Participants consisted of 17 men and 14 women (18-30 years) who were classified as being at least moderately physically active as defined by the International Physical Activity Questionnaire. Tendon force/elongation measures were obtained during an isometric plantarflexion contraction on an isokinetic dynamometer with simultaneous ultrasound imaging of the Achilles tendon approximate to the soleus myotendinous junction. Data were collected at rest, after a 10-minute treadmill walk, and after a fatigue protocol of 100 toe jumps performed in a Smith machine, with a load equaling 20% of body mass. We found greater tendon elongation, decreased stiffness, and lower Young's modulus only in women after the jumping exercise. Force and stress were not different between groups but decreased subsequent to the jumping exercise bout. In general, women had greater elongation and strain, less stiffness, and a lower Young's modulus during plantarflexor contraction. These data demonstrate differences in tendon mechanics between men and women and suggest a potential protective mechanism explaining the lower incidence of Achilles tendinopathy in women.

  10. 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 888.3025 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... flexor tendon of the hand. The device is implanted for a period of 2 to 6 months to aid growth of a...

  11. 21 CFR 888.3025 - Passive tendon prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Passive tendon prosthesis. 888.3025 Section 888.3025 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... flexor tendon of the hand. The device is implanted for a period of 2 to 6 months to aid growth of a...

  12. Ultrasonic evaluations of Achilles tendon mechanical properties poststroke

    PubMed Central

    Zhao, Heng; Ren, Yupeng; Wu, Yi-Ning; Liu, Shu Q.; Zhang, Li-Qun

    2009-01-01

    Spasticity, contracture, and muscle weakness are commonly observed poststroke in muscles crossing the ankle. However, it is not clear how biomechanical properties of the Achilles tendon change poststroke, which may affect functions of the impaired muscles directly. Biomechanical properties of the Achilles tendon, including the length and cross-sectional area, in the impaired and unimpaired sides of 10 hemiparetic stroke survivors were evaluated using ultrasonography. Elongation of the Achilles tendon during controlled isometric ramp-and-hold and ramping up then down contractions was determined using a block-matching method. Biomechanical changes in stiffness, Young's modulus, and hysteresis of the Achilles tendon poststroke were investigated by comparing the impaired and unimpaired sides of the 10 patients. The impaired side showed increased tendon length (6%; P = 0.04), decreased stiffness (43%; P < 0.001), decreased Young's modulus (38%; P = 0.005), and increased mechanical hysteresis (1.9 times higher; P < 0.001) compared with the unimpaired side, suggesting Achilles tendon adaptations to muscle spasticity, contracture, and/or disuse poststroke. In vivo quantitative characterizations of the tendon biomechanical properties may help us better understand changes of the calf muscle-tendon unit as a whole and facilitate development of more effective treatments. PMID:19118156

  13. Surgical Strategy for the Chronic Achilles Tendon Rupture

    PubMed Central

    Yang, Liu; Yin, Li

    2016-01-01

    Background. Chronic Achilles tendon rupture is usually misdiagnosed and treated improperly. This study aims to better understand the treatment of chronic Achilles tendon rupture. Methods. Patients who were not able to perform a single-limb heel rise were chosen. Pre- and postoperative magnetic resonance imaging (MRI) were conducted. By evaluating the presence or absence of Achilles tendon stumps and the gap length of rupture, V-Y advancement, gastrocnemius fascial turndown flap, or flexor halluces longus tendon transfer were selected for tendon repair. The function of ankle and foot was assessed by American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot scores and Achilles Tendon Total Rupture Score (ATRS). Results. Twenty-nine patients were followed up. One patient had superficial incision infection, which was healed after debridement and oral antibiotics. Three months postoperatively, MRI showed some signs of inflammation, which disappeared at one or two years postoperatively. All patients were able to perform a single-limb heel rise. Mean AOFAS scores and ATRS scores were increased at the latest follow-up. Conclusion. Surgical options can be determined by evaluating the presence of the Achilles tendon stumps and the gap length, which can avoid using the nearby tendon and yield satisfactory functional results. PMID:27847806

  14. Estimation of Musculotendon Kinematics under Controlled Tendon Indentation

    PubMed Central

    Chardon, Matthieu K.; Dhaher, Yasin Y.; Suresh, Nina I.; Jaramillo, Giselle; Rymer, W. Zev

    2015-01-01

    The effects of tendon indentation on musculotendon unit mechanics have been left largely unexplored. Tendon indentation is however routinely used in the tendon reflex exam to diagnose the state of reflex pathways. Because muscle mechanoreceptors are sensitive to mechanical changes of the musculotendon unit, this gap in knowledge could potentially impact our understanding of these neurological exams. Accordingly, we have used ultrasound (US) imaging to compare the effects of tendon indentation with the effects angular rotation of the elbow in six neurologically intact individuals. We used sagittal ultrasound movies of the biceps brachii to compare length changes induced by each of these perturbations. Length changes were quantified using a pixel-tracking protocol. Our results show that a 20 mm indentation of the distal tendon is broadly equivalent to a 15° elbow rotation. We also show that within the imaging window the strain differences between the two stretching protocols are statistically insignificant. Finally, we show that there exists a significant linear relationship between the two stretching techniques and that this relationship spans a large rotational angle to indentation depth. We have used a novel tendon probe to administer controlled tendon indentations as a way to characterize musculotendon kinematics. Using this probe, we confirm that tendon indentation can be physiologically equated with joint rotation, and can thus be used as an input for muscle stretching protocols. Furthermore, this is potentially a simpler and more practical alternative to externally imposed angular joint motion. PMID:26321363

  15. A biomechanical study of pediatric flexor profundus tendon repair

    PubMed Central

    Al-Thunayan, Turki A.; Al-Zahrani, Mohammed T.; Hakeem, Ahmad A.; Al-Zahrani, Fahad M.; Al-Qattan, Mohammad M.

    2016-01-01

    Objectives: To investigate the tensile strength of repaired flexor profundus tendons in young lambs, which would be equivalent to repairs in children older than 2 years of age. Methods: A comparative in-vitro experimental study conducted at King Saud University, Riyadh, Kingdom of Saudi Arabia from October 2014 to December 2015. We utilized 30 flexor profundus tendons of young lambs with a width of 4 mm. All tendons were repaired with a 4-strand repair technique using 4/0 polypropylene core sutures. In group I (n=10 tendons), 2 separate figure-of-eight sutures were applied. In group II (n=10 tendons), simple locking sutures were added to the corners of 2 separate figure-of-eight sutures. In group III (n=10 tendons), the locked cruciate repair was used. All tendon repairs were tested to single-cycle tensile failure. Results: There was no significant difference between groups II and III with regards to gap and breaking forces; and all forces of these 2 groups were significantly higher than the forces in group I. Conclusion: It was concluded that 4 mm-wide pediatric flexor tendons allow a 4-strand repair and the use of 4/0 sutures. The use of locking sutures increases the tensile strength to values that may allow protective mobilization in children. PMID:27570850

  16. Ultrasonic evaluations of Achilles tendon mechanical properties poststroke.

    PubMed

    Zhao, Heng; Ren, Yupeng; Wu, Yi-Ning; Liu, Shu Q; Zhang, Li-Qun

    2009-03-01

    Spasticity, contracture, and muscle weakness are commonly observed poststroke in muscles crossing the ankle. However, it is not clear how biomechanical properties of the Achilles tendon change poststroke, which may affect functions of the impaired muscles directly. Biomechanical properties of the Achilles tendon, including the length and cross-sectional area, in the impaired and unimpaired sides of 10 hemiparetic stroke survivors were evaluated using ultrasonography. Elongation of the Achilles tendon during controlled isometric ramp-and-hold and ramping up then down contractions was determined using a block-matching method. Biomechanical changes in stiffness, Young's modulus, and hysteresis of the Achilles tendon poststroke were investigated by comparing the impaired and unimpaired sides of the 10 patients. The impaired side showed increased tendon length (6%; P = 0.04), decreased stiffness (43%; P < 0.001), decreased Young's modulus (38%; P = 0.005), and increased mechanical hysteresis (1.9 times higher; P < 0.001) compared with the unimpaired side, suggesting Achilles tendon adaptations to muscle spasticity, contracture, and/or disuse poststroke. In vivo quantitative characterizations of the tendon biomechanical properties may help us better understand changes of the calf muscle-tendon unit as a whole and facilitate development of more effective treatments.

  17. Tendon Transfers Around the Foot: When and Where.

    PubMed

    Kuo, Ken N; Wu, Kuan-Wen; Krzak, Joseph J; Smith, Peter A

    2015-12-01

    Tendon transfers are invaluable in the treatment of severe children's foot deformities. They are often preferable to simple releases, lengthening, or fusion in surgical treatment because they provide an active motor function for deformity correction and, when properly selected, the procedures stabilize the foot against progressive deformity. The authors describe 4 commonly used tendon transfer procedures that are useful in children's foot deformity surgeries.

  18. Changes in the mechanical properties of patellar tendon preparations of spontaneously diabetic dogs under long-term insulin therapy.

    PubMed

    Lancaster, R L; Haut, R C; DeCamp, C E

    1994-08-01

    Diabetes mellitus is known to involve a wide range of musculoskeletal disorders including tendon contracture, tenosynovitis, joint stiffness, and osteoporosis. Recent studies with experimentally induced models of diabetes show that insulin therapy mitigates such alterations. These data are from relatively short-term experiments. This manuscript reports the results of tensile failure experiments on the canine patella-patellar tendon-tibia complex from a group of juvenile diabetic animals that received insulin therapy. The duration of the disease was 4-9 yr. The stiffness of the diabetic preparations in a physiological range of loading was approximately 13% greater than controls (P < 0.05). On the other hand, the strength of the tendon preparation from the diabetic population was not different from controls, but the mode of structural failure for controls was by substance and avulsion fractures while the diabetics failed by tensile fracture of the patella.

  19. Torque Control of Underactuated Tendon-driven Robotic Fingers

    NASA Technical Reports Server (NTRS)

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

  20. Bioreactor optimization of tissue engineered rabbit flexor tendons in vivo.

    PubMed

    Thorfinn, J; Angelidis, I K; Gigliello, L; Pham, H M; Lindsey, D; Chang, J

    2012-02-01

    Tissue-engineered rabbit flexor tendons reseeded with cells are stronger in vitro after culture in a bioreactor. It is not known whether this effect persists in vivo. Tenocytes from New Zealand white rabbits were seeded onto rabbit rear paw flexor tendons that were deprived of cells and exposed to cyclic strain in a bioreactor. Reseeded constructs that were kept unloaded in a medium for 5 days were used as controls. The tendons were implanted to bridge a zone II defect in the rabbit. After explantation 4 weeks later, the ultimate tensile strength (UTS) and elastic modulus (EM) were determined. Tendon constructs that were exposed to cyclic strain had significantly improved UTS and EM. Histology showed that cellularity was increased in the bioreactor tendons.

  1. 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.

  2. 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.

  3. Ethanol treatment of tendon allografts: a potential HIV inactivating procedure.

    PubMed

    Anastasescou, M; Cornu, O; Banse, X; König, J; Hassoun, A; Delloye, C

    1998-01-01

    The penetration rate of ethanol in human tendons was studied to in order to define the conditions which were necessary to achieve an inactivating concentration against the Human Immunodeficiency Virus (HIV) within the tendon. The rate of alcohol penetration was found to be slow and did not differ with different types of tendons. An average ethanol concentration of 14% (v/v) was measured in human tendons after they had been immersed for 2 h in 70% (v/v) ethanol, and a concentration of 19% (v/v) was reached after 3 h. Ethanol immersion of human tendons may represent an additional safety procedure in inactivating the HIV virus provided the duration is at least 3 h.

  4. Tendon disorders of the hand and wrist.

    PubMed

    McAuliffe, John A

    2010-05-01

    The terminology used to describe most common tendon disorders in the hand and wrist suggests that they are inflammatory in nature, although current evidence indicates that mechanical and degenerative factors are more important. Corticosteroid injections provide relief in 60% or more of cases; however, the duration of their effectiveness remains uncertain. Surgical release of the stenotic pulley or sheath is curative in well over 90% of cases; complications of surgery are rare, and relief is long-lasting. Enlightened management of these common problems demands evidence-based guidelines defining indications for surgery that will maximize outcomes and minimize costs.

  5. Mechanical model of a single tendon finger

    NASA Astrophysics Data System (ADS)

    Rossi, Cesare; Savino, Sergio

    2013-10-01

    The mechanical model of a single tendon three phalanxes finger is presented. By means of the model both kinematic and dynamical behavior of the finger itself can be studied. This finger is a part of a more complex mechanical system that consists in a four finger grasping device for robots or in a five finger human hand prosthesis. A first prototype has been realized in our department in order to verify the real behavior of the model. Some results of both kinematic and dynamical behavior are presented.

  6. New anchoring method for tarsal tendon transfers in myelomeningocele patients.

    PubMed

    Tomonori, Kenmoku; Makoto, Kamegaya; Takashi, Saisu

    2007-12-01

    We describe a new anchoring method for tarsal tendon transfers in myelomeningocele patients to protect the sole of the foot from pressure sores and skin necrosis and to loosen the tension of the transferred tendon.Tendon transfer procedures were performed in 51 feet (33 patients) with myelomeningocele. We transferred tibialis anterior tendons to the second or third cuneiform in 19 with equinovarus deformities, and transferred tibialis anterior tendons to the calcaneus through the interosseous membrane in 32 with talipes calcaneus. Clinical results were evaluated with the muscle power of transferred tendons using manual muscle testing 6 months after surgery. The muscle test result was classified as good, fair, and poor.After passing the tendon through the bony hole, a 2.0-mm Kirschner wire was inserted from the sole to the tibia through the ankle joint at neutral. (It extended from the sole through the posterior cortex of the tibia.) The remaining part of the wire was bent and formed into a loop shaped like the Greek letter "zeta" (zeta). The thread was then tied to the loop of the wire as tightly as possible. In this way, there was no contact with the sole during anchoring, thus avoiding ulcers. In addition, the transferred tendon could be kept stable because the patient's ankle was fixed by the Kirschner wire.No cases of wound infection or skin necrosis of the sole occurred. In 49 of the 51 cases, transferred tendons were firmly anchored to tarsal bones. Muscle strength was good for 83%, fair for 13%, and poor for 4%. Consequently, 45 feet could obtain plantigrade pattern during their walking with shoe inserts or occasional use of ankle-foot orthoses.Our anchoring method has the advantage of protecting the sole of the foot from pressure sores and skin necrosis, as well as maintaining tension on the transferred tendon until it settles down in an anchor hole.

  7. Characterization of mechanical and biochemical properties of developing embryonic tendon

    PubMed Central

    Marturano, Joseph E.; Arena, Jeffrey D.; Schiller, Zachary A.; Georgakoudi, Irene; Kuo, Catherine K.

    2013-01-01

    Tendons have uniquely high tensile strength, critical to their function to transfer force from muscle to bone. When injured, their innate healing response results in aberrant matrix organization and functional properties. Efforts to regenerate tendon are challenged by limited understanding of its normal development. Consequently, there are few known markers to assess tendon formation and parameters to design tissue engineering scaffolds. We profiled mechanical and biological properties of embryonic tendon and demonstrated functional properties of developing tendon are not wholly reflected by protein expression and tissue morphology. Using force volume-atomic force microscopy, we found that nano- and microscale tendon elastic moduli increase nonlinearly and become increasingly spatially heterogeneous during embryonic development. When we analyzed potential biochemical contributors to modulus, we found statistically significant but weak correlation between elastic modulus and collagen content, and no correlation with DNA or glycosaminoglycan content, indicating there are additional contributors to mechanical properties. To investigate collagen cross-linking as a potential contributor, we inhibited lysyl oxidase-mediated collagen cross-linking, which significantly reduced tendon elastic modulus without affecting collagen morphology or DNA, glycosaminoglycan, and collagen content. This suggests that lysyl oxidase-mediated cross-linking plays a significant role in the development of embryonic tendon functional properties and demonstrates that changes in cross-links alter mechanical properties without affecting matrix content and organization. Taken together, these data demonstrate the importance of functional markers to assess tendon development and provide a profile of tenogenic mechanical properties that may be implemented in tissue engineering scaffold design to mechanoregulate new tendon regeneration. PMID:23576745

  8. Sustained delivery of transforming growth factor beta three enhances tendon-to-bone healing in a rat model.

    PubMed

    Manning, Cionne N; Kim, H Mike; Sakiyama-Elbert, Shelly; Galatz, Leesa M; Havlioglu, Necat; Thomopoulos, Stavros

    2011-07-01

    Despite advances in surgical technique, rotator cuff repairs are plagued by a high rate of failure. This failure rate is in part due to poor tendon-to-bone healing; rather than regeneration of a fibrocartilaginous attachment, the repair is filled with disorganized fibrovascular (scar) tissue. Transforming growth factor beta 3 (TGF-β3) has been implicated in fetal development and scarless fetal healing and, thus, exogenous addition of TGF-β3 may enhance tendon-to-bone healing. We hypothesized that: TGF-β3 could be released in a controlled manner using a heparin/fibrin-based delivery system (HBDS); and delivery of TGF-β3 at the healing tendon-to-bone insertion would lead to improvements in biomechanical properties compared to untreated controls. After demonstrating that the release kinetics of TGF-β3 could be controlled using a HBDS in vitro, matrices were incorporated at the repaired supraspinatus tendon-to-bone insertions of rats. Animals were sacrificed at 14-56 days. Repaired insertions were assessed using histology (for inflammation, vascularity, and cell proliferation) and biomechanics (for structural and mechanical properties). TGF-β3 treatment in vivo accelerated the healing process, with increases in inflammation, cellularity, vascularity, and cell proliferation at the early timepoints. Moreover, sustained delivery of TGF-β3 to the healing tendon-to-bone insertion led to significant improvements in structural properties at 28 days and in material properties at 56 days compared to controls. We concluded that TGF-β3 delivered at a sustained rate using a HBDS enhanced tendon-to-bone healing in a rat model.

  9. Discrete wavelet transform to improve guided-wave-based health monitoring of tendons and cables

    NASA Astrophysics Data System (ADS)

    Rizzo, Piervincenzo; Lanza di Scalea, Francesco

    2004-07-01

    Multi-wire steel strands are used in civil structures as pre-stressing tendons in prestressed concrete and as stay-cables in cable-stayed and suspension bridges. Monitoring the structural performance of these components is important to ensure the proper functioning and safety of the entire structure. Among the various NDE techniques that are under investigation for monitoring tendons and cables, the use of ultrasonic guided waves shows good promises. The main advantage of this approach is the possibility for the simultaneous monitoring of loads and detection of defects, such as corrosion and broken wires, by using the same ultrasonic setup. Load monitoring is achieved by measuring the travel time of the wave across a given length of the cable. Defect detection is achieved by measuring the reflections of the wave from the geometrical discontinuities. The new contributions of the current paper are two-fold. First, the study identifies those ultrasonic frequencies propagating with low attenuation for long-range defect detection. Second, the technique is substantially improved by implementing the Discrete Wavelet Transform (DWT) as a data post-processing tool. The data de-noising and data compression abilities of the DWT allow for greater sensitivity, larger ranges and higher monitoring speed. It is shown that the implementation of the DWT in the ultrasonic guided-wave technique becomes necessary for monitoring tendons and cables in the field.

  10. Desmotomy for treatment of chronic desmitis of the accessory ligament of the deep digital flexor tendon in a horse.

    PubMed Central

    Todhunter, P G; Schumacher, J; Finn-Bodner, S T

    1997-01-01

    Chronic lameness was determined to be caused by desmitis of the accessory ligament of the deep digital flexor tendon and adhesions associated with these 2 structures. Desmotomy of the accessory ligament, resection of adhesions, and controlled exercise during convalescence resulted in return to normal use without apparent lameness. Images Figure 1. Figure 2. PMID:9332748

  11. Effects of Growth on Muscle, Tendon, and Aponeurosis Tissues in Rabbit Shank Musculature.

    PubMed

    Böl, Markus; Leichsenring, Kay; Siebert, Tobias

    2016-12-20

    There exist several studies using morphological analyses of skeletal muscles to obtain a better understanding of muscle structure. The structural information obtained are primarily determined from single muscle components using individual animals of discrete ages. Further, little is known about changing dimensions of the aponeurosis, which is an important load-transferring interface in muscle mechanics. Thus, the aim of the present study was to determine how the muscle, tendon, and particularly the aponeurosis geometry of the rabbit shank musculature (M. soleus, M. extensor digitorum longus, and M. plantaris) change during growth. In doing so, morphological studies on muscles of eighty-nine female rabbits aged between 18 and 108 days were conducted. We found an almost linear increase over time in all of the geometrical parameters observed. The aponeurosis of the muscles exhibited lower growth rates in width than in length. The distal and proximal aponeurosis areas were nearly identical. The ratio of aponeurosis area to the physiological cross-sectional area was 2.54, 2.54, and 1.88 for M. soleus, M. extensor digitorum longus, and M. plantaris, respectively. M. extensor digitorum longus and M. soleus exhibited a nearly similar tendon-muscle fascicle length ratio during growth, increasing from 2.86 to 5.30 and 3.48 to 6.16, respectively. Interestingly, the tendon-muscle fascicle length ratio of the M. plantaris started initially with a much higher value (∼8) and increased to ∼18. Taken together, these results provide insight into the structure of the muscle-tendon complex and thus, a general understanding of muscle growth. Anat Rec, 2016. © 2016 Wiley Periodicals, Inc.

  12. Ruptures of the distal biceps tendon.

    PubMed

    Ward, James P; Shreve, Mark C; Youm, Thomas; Strauss, Eric J

    2014-01-01

    Distal biceps ruptures occur most commonly in middle-aged males and result from eccentric contraction of the biceps tendon. The injury typically presents with pain and a tearing sensation in the antecubital fossa with resultant weakness in flexion and supination strength. Physical exam maneuvers and diagnostic imaging aid in determining the diagnosis. Nonoperative management is reserved for elderly, low demand patients, while operative intervention is generally pursued for younger patients and can consist of nonanatomic repair to the brachialis or anatomic repair to the radial tuberosity. Anatomic repair through a one-incision or two-incision approach is commonplace, while the nonanatomic repairs are rarely performed. No clear advantage exists in operative management with a one-incision versus two-incision techniques. Chronic ruptures present a more difficult situation, and allograft augmentation is often necessary. Common complications after repair include transient nerve palsy, which often resolves, and heterotopic ossification. Despite these possible complications, most studies suggest that better patient outcomes are obtained with operative, anatomic reattachment of the distal biceps tendon.

  13. The Effect of Sodium Hyaluronate on Ligamentation and Biomechanical Property of Tendon in Repair of Achilles Tendon Defect with Polyethylene Terephthalate Artificial Ligament: A Rabbit Tendon Repair Model

    PubMed Central

    Li, Shengkun; Jiang, Jia; Chen, Shiyi

    2016-01-01

    The Achilles tendon is the most common ruptured tendon of human body. Reconstruction with polyethylene terephthalate (PET) artificial ligament is recommended in some serious cases. Sodium hyaluronate (HA) is beneficial for the healing of tendon injuries. We aimed to determine the effect of sodium hyaluronate in repair of Achilles tendon defect with PET artificial ligament in an animal tendon repair model. Sixteen New Zealand White rabbits were divided into two groups. Eight rabbits repaired with PET were assigned to PET group; the other eight rabbits repaired with PET along with injection of HE were assigned to HA-PET group. All rabbits were sacrificed at 4 and 8 weeks postoperatively for biomechanical and histological examination. The HA-PET group revealed higher biomechanical property compared with the PET group. Histologically, more collagen tissues grew into the HA-PET group compared with PET group. In conclusion, application of sodium hyaluronate can improve the healing of Achilles tendon reconstruction with polyethylene terephthalate artificial ligament. PMID:28105436

  14. Changes induced by ozone and ultraviolet light in type I collagen. Bovine Achilles tendon collagen versus rat tail tendon collagen.

    PubMed

    Fujimori, E

    1985-10-15

    High-molecular-mass aggregates were made soluble from insoluble collagens of bovine Achilles tendon and rat tail tendon by limited thermal hydrolysis. These polymeric collagen aggregates were cross-linked by 390-nm-fluorescent 3-hydroxy-pyridinium residues (excited at 325 nm) in the former tendon and by unknown non-fluorescent residues in the latter. With the solubilized insoluble-collagens from both tendons, as well as with acid-soluble collagen from rat tail tendon, other 350-385-nm fluorescence intensities (excited at 300 nm) were found to be higher in monomeric chains than in dimeric and polymeric chains. Low levels of ozone inhibited fibril formation of acid-soluble collagen particularly from young rat tail tendon, reacting with tyrosine residues and the 350-385-nm fluorophores. Aldehyde groups, involved in cross-linking, were not effectively modified by ozone. beta-Components (alpha-chain dimers) were not efficiently dissociated even by higher doses of ozone compared to gamma-components (alpha-chain trimers). Polymeric chain aggregates from bovine Achilles tendon collagen, whose 3-hydroxy-pyridinium cross-links are cleaved by ozone, were more readily dissociated by ozone than those from rat tail tendon collagen. Ultraviolet (300-nm) light, which destroyed the 350-385-nm fluorophores, inhibited fibril formation less effectively than ultraviolet (275-nm) light, which is absorbed by tyrosine residues, and did not dissociate collagen polymers from rat tail tendon. On the other hand, ultraviolet (320-nm) light, absorbed by 3-hydroxy-pyridinium cross-links which were rapidly photolyzed, partially dissociated polymeric collagen aggregates from bovine Achilles tendon after subsequent heating.

  15. Calcium phosphate-hybridized tendon graft to enhance tendon-bone healing two years after ACL reconstruction in goats

    PubMed Central

    2011-01-01

    Background We developed a novel technique to improve tendon-bone attachment by hybridizing calcium phosphate (CaP) with a tendon graft using an alternate soaking process. However, the long-term result with regard to the interface between the tendon graft and the bone is unclear. Methods We analyzed bone tunnel enlargement by computed tomography and histological observation of the interface and the tendon graft with and without the CaP hybridization 2 years after anterior cruciate ligament (ACL) reconstruction in goats using EndoButton and the postscrew technique (CaP, n = 4; control, n = 4). Results The tibial bone tunnel enlargement rates in the CaP group were lower than those in the control group (p < 0.05). In the CaP group, in the femoral and tibial bone tunnels at the anterior and posterior of the joint aperture site, direct insertion-like formation that contained a cartilage layer without tidemarks was more observed at the tendon-bone interface than in the control group (p < 0.05). Moreover, the gap area between the tendon graft and the bone was more observed at the femoral bone tunnel of the joint aperture site in the control group than in the CaP group (p < 0.05). The maturation of the tendon grafts determined using the ligament tissue maturation index was similar in both groups. Conclusions The CaP-hybridized tendon graft enhanced the tendon-bone healing 2 years after ACL reconstruction in goats. The use of CaP-hybridized tendon grafts can reduce the bone tunnel enlargement and gap area associated with the direct insertion-like formation in the interface near the joint. PMID:22166674

  16. Anatomic Variations of the First Extensor Compartment and Abductor Pollicis Longus Tendon in Trapeziometacarpal Arthritis

    PubMed Central

    Opreanu, Razvan C.; Wechter, John; Tabbaa, Hazem; Kepros, John P.; Baulch, Michelle; Xie, Yan; Lackey, Wendy

    2009-01-01

    Anatomic variation of the trapeziometacarpal joint stabilizing structures is one of the concepts proposed to explain the pathogenesis of trapeziometacarpal arthritis. We undertook this study to test the hypothesis that septation of the first extensor compartment or variation of the abductor pollicis longus (APL) tendon (supernumerary insertions) are more frequently associated with the progression or severity of trapeziometacarpal arthritis. Septation within the first extensor compartment was significantly associated with trapeziometacarpal arthritis (p = 0.013), whereas supernumerary APL insertions (trapezium or thenar) did not reveal a significant association (p = 0.811 and p = 0.937, respectively). The results of this study do not support a role for variations of APL tendon insertions in trapeziometacarpal arthritis. Yet, the presence of septation within the first extensor compartment may play an important role in the pathogenesis of trapeziometacarpal arthritis. PMID:19834771

  17. 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 Central

    Hase, E.; Sato, K.; Yonekura, D.; Minamikawa, T.; Takahashi, M.

    2016-01-01

    Objectives 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. Materials and Methods 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. Results 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 (R2 = 0.37) with Young’s modulus obtained from the tensile testing. Conclusion 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. PMID:27881441

  18. Effect of toe and heel elevation on calculated tendon strains in the horse and the influence of the proximal interphalangeal joint.

    PubMed

    Lawson, Siân E M; Chateau, Henry; Pourcelot, Philippe; Denoix, Jean-Marie; Crevier-Denoix, Nathalie

    2007-05-01

    The sagittal alteration of hoof balance is a common intervention in horses, with corrective shoeing being one of the most frequently applied methods of managing tendonitis. However, the effect of toe or heel elevation on tendon strains is poorly understood. This study aimed to examine the effect of toe and heel wedges on the superficial digital flexor tendon, deep digital flexor tendon, and the third interosseous muscle or suspensory ligament strains using in vivo data and an accurate subject-specific model. Kinematic data were recorded using invasive markers at the walk and trot. Computerized tomography was then used to create a subject-specific model of an equine distal forelimb and strains were calculated for the superficial digital flexor tendon, the deep digital flexor tendon accessory ligament and the suspensory ligament for seven trials each of normal shoes, and toe and heel elevation. As the proximal interphalangeal joint is often ignored in strain calculations, its influence on the strain calculations was also tested. The deep ligament showed the same results for walk and trot with the heel wedge decreasing peak strain and the toe wedge increasing it. The opposite results were seen in the suspensory ligament and the superficial digital flexor tendon with the heel wedge increasing peak strain and the toe wedge decreasing it. The proximal interphalangeal joint was shown to be influential on the strains calculated with normal shoes and the calculated effect of the wedges. Our results imply that corrective shoeing appears to decrease strain in the tendon being targeted; the possibility of increases in strain in other structures should also be considered.

  19. Elbow tendinopathy and tendon ruptures: epicondylitis, biceps and triceps ruptures.

    PubMed

    Rineer, Craig A; Ruch, David S

    2009-03-01

    Lateral and medial epicondylitis are common causes of elbow pain in the general population, with the lateral variety being more common than the medial by a ratio reportedly ranging from 4:1 to 7:1. Initially thought to be an inflammatory condition, epicondylitis has ultimately been shown to result from tendinous microtearing followed by an incomplete reparative response. Numerous nonoperative and operative treatment options have been employed in the treatment of epicondylitis, without the emergence of a single, consistent, universally accepted treatment protocol. Tendon ruptures about the elbow are much less frequent, but result in more significant disability and loss of function. Distal biceps tendon ruptures typically occur in middle-aged males as a result of an event that causes a sudden, eccentric contraction of the biceps. Triceps tendon ruptures are exceedingly rare but usually have a similar etiology with a forceful eccentric contraction of the triceps that causes avulsion of the tendon from the olecranon. The diagnosis of these injuries is not always readily made. Complete ruptures of the biceps or triceps tendons have traditionally been treated surgically with good results. With regard to biceps ruptures, there continues to be debate about the best surgical approach, as well as the best method of fixation of tendon to bone. This article is not meant to be an exhaustive review of the broad topics of elbow tendinopathy and tendon ruptures, but rather is a review of recently published information on the topics that will assist the clinician in diagnosis and management of these conditions.

  20. Temporal Healing in Rat Achilles Tendon: Ultrasound Correlations

    PubMed Central

    Chamberlain, Connie S.; Duenwald-Kuehl, Sarah E.; Okotie, Gregory; Brounts, Sabrina H.; Baer, Geoffrey S.; Vanderby, Ray

    2012-01-01

    The purpose of this study was to explore whether a new ultrasound-based technique correlates with mechanical and biological metrics that describe the tendon healing. Achilles tendons in 32 rats were unilaterally transected and allowed to heal without repair. At 7, 9, 14, or 29 days post-injury, tendons were collected and examined for healing via ultrasound image analysis, mechanical testing, and immunohistochemistry. Consistent with previous studies, we observe that the healing tendons are mechanically inferior (ultimate stress, ultimate load, and normalized stiffness) and biologically altered (cellular and ECM factors) compared to contralateral controls with an incomplete recovery over healing time. Unique to this study, we report: 1) Echo intensity (defined by gray-scale brightness in the ultrasound image) in the healing tissue is related to stress and normalized stiffness. 2) Elongation to failure is relatively constant so that tissue normalized stiffness is linearly correlated with ultimate stress. Together, 1 and 2 suggest a method to quantify mechanical compromise in healing tendons. 3) The amount and type of collagen in healing tendons associates with their strength and normalized stiffness as well as their ultrasound echo intensity. 4) A significant increase of periostin in the healing tissues suggests an important but unexplored role for this ECM protein in tendon healing. PMID:23149902

  1. Incorporating Plasticity of the Interfibrillar Matrix in Shear Lag Models is Necessary to Replicate the Multiscale Mechanics of Tendon Fascicles

    PubMed Central

    Szczesny, Spencer E.; Elliott, Dawn M.

    2015-01-01

    Despite current knowledge of tendon structure, the fundamental deformation mechanisms underlying tendon mechanics and failure are unknown. We recently showed that a shear lag model, which explicitly assumed plastic interfibrillar load transfer between discontinuous fibrils, could explain the multiscale fascicle mechanics, suggesting that fascicle yielding is due to plastic deformation of the interfibrillar matrix. However, it is unclear whether alternative physical mechanisms, such as elastic interfibrillar deformation or fibril yielding, also contribute to fascicle mechanical behavior. The objective of the current work was to determine if plasticity of the interfibrillar matrix is uniquely capable of explaining the multiscale mechanics of tendon fascicles including the tissue post-yield behavior. This was examined by comparing the predictions of a continuous fibril model and three separate shear lag models incorporating an elastic, plastic, or elastoplastic interfibrillar matrix with multiscale experimental data. The predicted effects of fibril yielding on each of these models were also considered. The results demonstrated that neither the continuous fibril model nor the elastic shear lag model can successfully predict the experimental data, even if fibril yielding is included. Only the plastic or elastoplastic shear lag models were capable of reproducing the multiscale tendon fascicle mechanics. Differences between these two models were small, although the elastoplastic model did improve the fit of the experimental data at low applied tissue strains. These findings suggest that while interfibrillar elasticity contributes to the initial stress response, plastic deformation of the interfibrillar matrix is responsible for tendon fascicle post-yield behavior. This information sheds light on the physical processes underlying tendon failure, which is essential to improve our understanding of tissue pathology and guide the development of successful repair. PMID:25262202

  2. Imaging and simulation of Achilles tendon dynamics: Implications for walking performance in the elderly.

    PubMed

    Franz, Jason R; Thelen, Darryl G

    2016-06-14

    The Achilles tendon (AT) is a complex structure, consisting of distinct fascicle bundles arising from each triceps surae muscle that may act as mechanically independent structures. Advances in tissue imaging are rapidly accelerating our understanding of the complexities of functional Achilles tendon behavior, with potentially important implications for musculoskeletal injury and performance. In this overview of our recent contributions to these efforts, we present the results of complementary experimental and computational approaches to investigate AT behavior during walking and its potential relevance to reduced triceps surae mechanical performance due to aging. Our experimental evidence reveals that older tendons exhibit smaller differences in tissue deformations than young adults between regions of the AT presumed to arise from the gastrocnemius and soleus muscles. These observations are consistent with a reduced capacity for inter-fascicle sliding within the AT, which could have implications for the mechanical independence of the triceps surae muscles. More uniform AT deformations are also correlated with hallmark biomechanical features of elderly gait - namely, a loss of net ankle moment, power, and positive work during push-off. Simulating age-related reductions in the capacity for inter-fascicle sliding in the AT during walking predicts detriments in gastrocnemius muscle-tendon mechanical performance coupled with underlying shifts in fascicle kinematics during push-off. AT compliance, also suspected to vary due to age, systematically modulates those effects. By integrating in vivo imaging with computational modeling, we have gained theoretical insight into multi-scale biomechanical changes due to aging, hypotheses regarding their functional effects, and opportunities for experiments that validate or invalidate these assertions.

  3. A new non-metallic anchorage system for post-tensioning applications using CFRP tendons

    NASA Astrophysics Data System (ADS)

    Taha, Mahmoud Reda

    The objective of the work described in this thesis is to design, develop and test a new non-metallic anchorage system for post-tensioning applications using CFRP tendons. The use of a non-metallic anchorage system should eliminate corrosion and deterioration concerns in the anchorage zone. The development of a reliable non-metallic anchorage would provide an important contribution to this field of knowledge. The idea of the new anchorage is to hold the tendon through mechanical gripping. The anchorage consists of a barrel with a conical housing and four wedges. The anchorage components are made of ultra high performance concrete (UHPC) specially developed for the anchorage. Sixteen concrete mixtures with different casting and curing regimes were examined to develop four UHPC mixtures with compressive strengths in excess of 200 MPa. The UHPC mixtures showed very dense microstructures with some unique characteristics. To enhance the fracture toughness of the newly developed UHPC, analytical and experimental analyses were performed. Using 3 mm chopped carbon fibres, a significant increase in the fracture toughness of UHPC was achieved. The non-metallic anchorage was developed with the UHPC with enhanced fracture toughness. The barrel required careful wrapping with CFRP sheets to provide the confinement required to utilize the strength and toughness of the UHPC. Thirty-three anchorages were tested under both static and dynamic loading conditions. The non-metallic anchorage showed excellent mechanical performance and fulfilled the different requirements of a post-tensioning anchorage system. The development of the new non-metallic anchorage will widen the inclusion of CFRP tendons in post-tensioned concrete/masonry structures. The new system will offer the opportunity to exploit CFRP tendons effectively creating an innovative generation of corrosion-free, smart structures.

  4. Mechanical properties of the flexor digitorum profundus tendon attachment.

    PubMed

    Felder, Jerrod J; Guseila, Loredana M; Saranathan, Archana; Shary, Timothy J; Lippitt, Steven B; Elias, John J

    2013-12-01

    The current study was performed to determine the strength and rigidity of the intact flexor digitorum profundus (FDP) tendon attachment and compare the rigidity at the attachment site to the rigidity within a more proximal part of the tendon. Eight cadaveric index fingers were tested to failure of the FDP tendon. Lines were drawn on each tendon with India ink stain at the position of the attachment to bone and 5 mm and 10 mm proximally. Each test was recorded using a high resolution video camera. A minimum of six images per test were used for analysis of tissue deformation. The centroid of each line was computationally identified to characterize the deformation of the tendon between the lines. Force vs. deformation curves were generated for the 5 mm region representing the tendon attachment and the 5 mm region adjacent to the attachment. Stiffness measurements were generated for each curve, and normalized by the initial length to determine the rigidity. The failure strength ranged from 263 N to 548 N, with rigidity values ranging from 2201 N/(mm/mm) to 8714 N/(mm/mm) and from 3459 N/(mm/mm) to 6414 N/(mm/mm) for the attachment and the tendon proximal to the attachment, respectively. The rigidity did not vary significantly between the attachment and proximal tendon based on a Wilcoxon signed rank test (p = 0.2). The measured strength and rigidity establish biomechanical properties for the FDP tendon attachment to bone.

  5. Multiple tendon xanthomas in patient with heterozygous familial hypercholesterolaemia: sonographic and MRI findings

    PubMed Central

    Dagistan, Emine; Canan, Arzu; Kizildag, Betul; Barut, Abdullah Yuksel

    2013-01-01

    Tendon xanthomas are a component of familial hypercholesterolaemia, which is a hereditary disease and characterised by elevated low-density lipo protein cholesterol plasma levels and premature coronary artery disease. Tendon xanthomas are diagnostic for heterozygous familial hypercholesterolaemia (HFH) and they mostly occur in Achilles tendon. Sonography and MRI are superior to clinical assessment and are useful in detecting tendon xanthomas. In this report, we present ultrasonographic and MRI findings of multiple tendon xanthomas in a case of HFH. PMID:24252837

  6. Development and Application of a Tendon Prosthesis for Early Functional Restoration of the Hand.

    DTIC Science & Technology

    1975-09-01

    blood supply, Hunter tendon, ,tendon synovial fluid tendon prosthesis, tendon pseudo sheath, tendon anastawsis. 20L ASIr RACT (Cw - rev e I nemwee.y am...Healing Process 1. Synovial Fluid Characterizatio : A technique has bee defined that is capable of extracting small micro quantities of fluids from...prosthesis is being studied in the dog and primate with referen ce to gliding pseudo sheath fo=- ation, fluid formation and distal and proximal

  7. Incidence of Major Tendon Ruptures and Anterior Cruciate Ligament Tears in US Army Soldiers

    DTIC Science & Technology

    2007-08-01

    patellar tendon [PT], and Achilles tendon [AT]) has increased in recent decades presumably because of increased recreational sports activity in our...1995 and 1996 were identified and evaluated for risk factors. Results: The authors identified 52 major tendon ruptures: 29 Achilles, 12 patellar , 7... patellar tendon rupture; Achilles tendon rupture; race; mechanism of injury *Address correspondence to LTC Daniel W. White, MD, 1 Jarrett White Road

  8. The long head of the biceps tendon is a suitable cell source for tendon tissue regeneration

    PubMed Central

    Pietschmann, Matthias F.; Gülecyüz, Mehmet F.; Ficklscherer, Andreas; Jansson, Volkmar; Müller, Peter E.

    2014-01-01

    Introduction Tendon tissue engineering (TTE) tries to produce tendinous tissue of high quality to replace dysfunctional tissue. One possible application of TTE might be the replacement of ruptured tissue of the rotator cuff. Autologous tenocytes seem to be most suitable as no differentiation in vitro is necessary. Today it is still uncertain if there is a difference between tendon-derived cells (TDC) of different native tissues. Moreover, the search for suitable scaffolds is another important issue in TTE. Material and methods This study compared TDC of the long head of the biceps tendon (LHB), the anterior cruciate ligament (ACL) and the tendon of the musculus semitendinosus (TMS). The TDC were isolated using the cell migration method. Cell morphology was assessed using light microscopy and gene expression was performed using polymerase chain reaction (PCR). Afterwards, cell seeding efficiency and proliferation were tested on a collagen I scaffold using the WST-1 assay. Results were confirmed using H + E staining. Results The TDC of the LHB showed higher expression levels of collagen type I and decorin (p < 0.01) compared to TDC of other origin. Results showed efficient cell seeding and proliferation within the scaffold. Proliferation within the scaffold was not as high as when cells were cultivated without a scaffold. Conclusions The TDC of the LHB seems to be the most suitable cell source. Further research is necessary to find out if the results can be transferred to an in vivo model. The new collagen I scaffold seems to offer an opportunity to combine good biocompatibility and mechanical strength. PMID:25097592

  9. Iliopsoas tendonitis caused by overhang of a collared femoral prosthesis.

    PubMed

    Brew, Christopher J; Stockley, Ian; Grainger, Andrew J; Stone, Martin H

    2011-04-01

    Pain after total hip arthroplasty can be due to a variety of causes, one of the less common being iliopsoas tendonitis. We report an unusual case of iliopsoas tendonitis caused by overhang of the femoral calcar by a collared femoral prosthesis resulting in impingement on the iliopsoas tendon. An ultrasound-guided corticosteroid and local anesthetic diagnostic injection to the site of impingement confirmed the diagnosis with temporary symptom relief. Revision of the femoral stem to a collarless prosthesis resulted in immediate and complete resolution of symptoms.

  10. Chronic Achilles Tendon Disorders: Tendinopathy and Chronic Rupture.

    PubMed

    Maffulli, Nicola; Via, Alessio Giai; Oliva, Francesco

    2015-10-01

    Tendinopathy of the Achilles tendon involves clinical conditions in and around the tendon and it is the result of a failure of a chronic healing response. Although several conservative therapeutic options have been proposed, few of them are supported by randomized controlled trials. The management is primarily conservative and many patients respond well to conservative measures. If clinical conditions do not improve after 6 months of conservative management, surgery is recommended. The management of chronic ruptures is different from that of acute ruptures. The optimal surgical procedure is still debated. In this article chronic Achilles tendon disorders are debated and evidence-based medicine treatment strategies are discussed.

  11. Primary flexor tendon surgery: the search for a perfect result.

    PubMed

    Elliot, David; Giesen, Thomas

    2013-05-01

    Repair of the divided flexor tendon to achieve normal, or near normal, function is an unsolved problem, with each result still uncertain. The authors believe the way forward in primary flexor tendon surgery clinically is by use of strengthened but simpler sutures, appropriate venting of the pulley system, and maintaining early rehabilitation. However, there needs also be consideration of patient factors and other aspects. Research needs to continue more widely, in both the laboratory and the clinical environment, to find ways of better modifying adhesions after surgical repair of the tendon.

  12. Bilateral simultaneous infrapatellar tendon ruptures: a case study.

    PubMed

    Noteboom, J T; Lester, M N

    1994-09-01

    This case study reports on a patient with a diagnosis of bilateral patellar tendon ruptures. Bilateral ruptures of the infrapatellar tendons are rare occurrences; approximately 20 cases have been reported in the medical literature. Much of the medical literature concentrates on surgical repair, immediate postoperative follow-up, and final outcome. There is a void in the literature concerning the rehabilitative process of these patients. The subject of this study is a 26-year-old male former collegiate athlete who suffered simultaneous bilateral patellar tendon ruptures while jumping. A rehabilitation model is provided that may assist others treating patients with similar conditions.

  13. Human hamstring tenocytes survive when seeded into a decellularized porcine Achilles tendon extracellular matrix.

    PubMed

    Lohan, Anke; Stoll, Christiane; Albrecht, Marit; Denner, Andreas; John, Thilo; Krüger, Kay; Ertel, Wolfgang; Schulze-Tanzil, Gundula

    2013-01-01

    Tendon ruptures and defects remain major orthopaedic challenges. Tendon healing is a time-consuming process, which results in scar tissue with an altered biomechanical competence. Using a xenogeneic tendon extracellular matrix (ECM) as a natural scaffold, which can be reseeded with autologous human tenocytes, might be a promising approach to reconstruct damaged tendons. For this purpose, the porcine Achilles (AS) tendons serving as a scaffold were histologically characterized in comparison to human cell donor tendons. AS tendons were decellularized and then reseeded with primary human hamstring tenocytes using cell centrifuging, rotating culture and cell injection techniques. Vitality testing, histology and glycosaminoglycan/DNA quantifications were performed to document the success of tendon reseeding. Porcine AS tendons were characterized by a higher cell and sulfated glycosaminoglycan content than human cell donor tendons. Complete decellularization could be achieved, but led to a wash out of sulfated glycosaminoglycans. Nevertheless, porcine tendon could be recellularized with vital human tenocytes. The recellularization led to a slight increase in cell number compared to the native tendon and some glycosaminoglycan recovery. This study indicates that porcine tendon can be de- and recellularized using adult human tenocytes. Future work should optimize cell distribution within the recellularized tendon ECM and consider tendon- and donor species-dependent differences.

  14. Tension Stiffened and Tendon Actuated Manipulator

    NASA Technical Reports Server (NTRS)

    Doggett, William R. (Inventor); Dorsey, John T. (Inventor); Ganoe, George G. (Inventor); King, Bruce D. (Inventor); Jones, Thomas C. (Inventor); Mercer, Charles D. (Inventor); Corbin, Cole K. (Inventor)

    2015-01-01

    A tension stiffened and tendon actuated manipulator is provided performing robotic-like movements when acquiring a payload. The manipulator design can be adapted for use in-space, lunar or other planetary installations as it is readily configurable for acquiring and precisely manipulating a payload in both a zero-g environment and in an environment with a gravity field. The manipulator includes a plurality of link arms, a hinge connecting adjacent link arms together to allow the adjacent link arms to rotate relative to each other and a cable actuation and tensioning system provided between adjacent link arms. The cable actuation and tensioning system includes a spreader arm and a plurality of driven and non-driven elements attached to the link arms and the spreader arm. At least one cable is routed around the driven and non-driven elements for actuating the hinge.

  15. Rehabilitating Psoas Tendonitis: A Case Report

    PubMed Central

    2008-01-01

    This case report describes the examination and physical therapy intervention for a woman with anterior hip pain whose medical diagnosis following magnetic resonance imaging (MRI) was bilateral labral tears and psoas tendinitis. Her physical therapy evaluation revealed findings consistent with psoas tendonitis. Utilizing theories of neuromuscular patterning and knowledge of normal muscle function, the patient was successfully treated in physical therapy following six physical therapy sessions, once a week for 6 weeks. The patient was found to have an overactive psoas muscle, as indicated by hip flexion being the primary mover in her movement patterns, and dysfunctional abdominal and pelvic floor muscles. Functionally based therapeutic exercise and electrical stimulation were used to reeducate the muscles of the abdomen, pelvic floor, and hips in order to create muscular balance and correct muscle dysfunction. PMID:19048347

  16. The high variability of the chiasma plantare and the long flexor tendons: Anatomical aspects of tendon transfer in foot surgery.

    PubMed

    Pretterklieber, Bettina

    2017-02-03

    As tendon transfer of the flexor hallucis longus (FHL) and the flexor digitorum longus (FDL) is an established procedure, exact knowledge of the formation of the chiasma plantare is of great interest. Although the quadratus plantae (QP) appears to play a major role, it has been rarely addressed in previous studies. The aim of the present study was to reinvestigate the formation of the chiasma plantare and the composition of the long flexor tendons in order to clarify the inexact and partly contradictory descriptions published from 1865 onward. The chiasma plantare and the long flexor tendons in both feet of 50 formalin-fixed specimens of body donors (25 men and women) were analyzed by gross anatomical dissection. It was composed of one (3%), two (69%) or three layers (28%) which were variably established by the tendinous and muscular fibers of the FHL, the FDL and the QP. In 61% the FHL gave one or more slips to the FDL, and in 39% there was a bidirectional interconnection between the two tendons. The slip from the FHL to the FDL largely reinforces the second (45%), or the second and third tendon (46%). Thus, the FHL is involved in the first tendon in all cases, in the second one in 97% of cases, and in the third tendon in about one half of cases (53%). In all instances, the FDL contributes to the third to fourth, in 98% the second, and in at least 39% to the first tendon. The QP reinforces the second to fourth tendon in nearly all cases, the fifth in about one half of cases, and even the first tendon in 14% of cases. In addition, the individual composition of the five long flexor tendons arising from the chiasma plantare was analyzed in detail. Special emphasis was placed on the evaluation of side and sex differences as well as individual symmetry. Furthermore, biomechanical, developmental and phylogenetic aspects were outlined. In terms of the outcome of this study, the FHL appears to be the better donor for tendon transfer to restore lost function, but

  17. Direct end-to-end repair of flexor pollicis longus tendon lacerations.

    PubMed

    Nunley, J A; Levin, L S; Devito, D; Goldner, R D; Urbaniak, J R

    1992-01-01

    Between 1976 and 1986, 38 consecutive acute isolated flexor pollicis longus lacerations were repaired. This study excluded all replanted or mutilated digits and all lacerations with associated fracture. Average follow-up was 26 months. Tendon rehabilitation was standardized. Range of motion and pinch strength were measured postoperatively. Seventy-four percent (28/38) of the flexor pollicis longus injuries occurred in zone II. Neurovascular injury occurred in 82% of the lacerations, and this correlated with the zone of tendon injury. In 21% of the patients (8/38) both digital nerves and arteries were transected. Postoperative thumb interphalangeal motion averaged 35 degrees and key pinch strength was 81% that of the uninjured thumb. One rupture occurred in a child. Laceration of the flexor pollicis longus is likely to involve damage to neurovascular structures, and repair may be necessary. Direct end-to-end repairs within the pulley system do at least as well as delayed tendon reconstruction and do not require additional procedures.

  18. [Bursitis with severe tendon and muscle necrosis on the lateral stifle area in cattle].

    PubMed

    Nuss, K; Räber, M; Sydler, T; Muggli, E; Hässig, M; Guscetti, F

    2011-11-01

    In 21 animals, chronic swelling on the lateral aspect of the stifle also known as «perigonitis», «stable-syndrome» or «bursitis bicipitalis femoris» were evaluated. Ultrasonography showed increased fluid in the distal subtendinous bursa of the biceps femoris muscle and structural changes in the tendons, muscles, subcutis and fasciae. Soft tissue swelling and an irregular contour of the lateral tibial condyle were typical signs on radiographs. Macroscopic changes were found at the insertion of the biceps femoris muscle, the distal subtendinous bursa of the biceps femoris muscle, the lateral collateral ligament of the stifle, the origin of muscles on the lateral femoral condyle and the lateral tibial condyle. They mainly consisted of tendon and muscle tissue necrosis with granulation tissue. Histology revealed areas of coagulation necrosis in tendons and ligaments, in which occasionally Onchocerca spp. were seen. The severity of lesions correlated well with the clinical signs, which were associated with a poor prognosis in advanced cases.

  19. Experimental and Computational Investigation of Viscoelasticity of Native and Engineered Ligament and Tendon

    NASA Astrophysics Data System (ADS)

    Ma, J.; Narayanan, H.; Garikipati, K.; Grosh, K.; Arruda, E. M.

    The important mechanisms by which soft collagenous tissues such as ligament and tendon respond to mechanical deformation include non-linear elasticity, viscoelasticity and poroelasticity. These contributions to the mechanical response are modulated by the content and morphology of structural proteins such as type I collagen and elastin, other molecules such as glycosaminoglycans, and fluid. Our ligament and tendon constructs, engineered from either primary cells or bone marrow stromal cells and their autogenous matricies, exhibit histological and mechanical characteristics of native tissues of different levels of maturity. In order to establish whether the constructs have optimal mechanical function for implantation and utility for regenerative medicine, constitutive relationships for the constructs and native tissues at different developmental levels must be established. A micromechanical model incorporating viscoelastic collagen and non-linear elastic elastin is used to describe the non-linear viscoelastic response of our homogeneous engineered constructs in vitro. This model is incorporated within a finite element framework to examine the heterogeneity of the mechanical responses of native ligament and tendon.

  20. Controlled Bioactive Molecules Delivery Strategies for Tendon and Ligament Tissue Engineering using Polymeric Nanofibers.

    PubMed

    Hiong Teh, Thomas Kok; Hong Goh, James Cho; Toh, Siew Lok

    2015-01-01

    The interest in polymeric nanofibers has escalated over the past decade given its promise as tissue engineering scaffolds that can mimic the nanoscale structure of the native extracellular matrix. With functionalization of the polymeric nanofibers using bioactive molecules, localized signaling moieties can be established for the attached cells, to stimulate desired biological effects and direct cellular or tissue response. The inherently high surface area per unit mass of polymeric nanofibers can enhance cell adhesion, bioactive molecules loading and release efficiencies, and mass transfer properties. In this review article, the application of polymeric nanofibers for controlled bioactive molecules delivery will be discussed, with a focus on tendon and ligament tissue engineering. Various polymeric materials of different mechanical and degradation properties will be presented along with the nanofiber fabrication techniques explored. The bioactive molecules of interest for tendon and ligament tissue engineering, including growth factors and small molecules, will also be reviewed and compared in terms of their nanofiber incorporation strategies and release profiles. This article will also highlight and compare various innovative strategies to control the release of bioactive molecules spatiotemporally and explore an emerging tissue engineering strategy involving controlled multiple bioactive molecules sequential release. Finally, the review article concludes with challenges and future trends in the innovation and development of bioactive molecules delivery using polymeric nanofibers for tendon and ligament tissue engineering.

  1. Proteomic differences between native and tissue‐engineered tendon and ligament

    PubMed Central

    Tew, Simon R.; Peffers, Mandy; Canty‐Laird, Elizabeth G.; Comerford, Eithne

    2016-01-01

    Tendons and ligaments (T/Ls) play key roles in the musculoskeletal system, but they are susceptible to traumatic or age‐related rupture, leading to severe morbidity as well as increased susceptibility to degenerative joint diseases such as osteoarthritis. Tissue engineering represents an attractive therapeutic approach to treating T/L injury but it is hampered by our poor understanding of the defining characteristics of the two tissues. The present study aimed to determine differences in the proteomic profile between native T/Ls and tissue engineered (TE) T/L constructs. The canine long digital extensor tendon and anterior cruciate ligament were analyzed along with 3D TE fibrin‐based constructs created from their cells. Native tendon and ligament differed in their content of key structural proteins, with the ligament being more abundant in fibrocartilaginous proteins. 3D T/L TE constructs contained less extracellular matrix (ECM) proteins and had a greater proportion of cellular‐associated proteins than native tissue, corresponding to their low collagen and high DNA content. Constructs were able to recapitulate native T/L tissue characteristics particularly with regard to ECM proteins. However, 3D T/L TE constructs had similar ECM and cellular protein compositions indicating that cell source may not be an important factor for T/L tissue engineering. PMID:27080496

  2. [The echographic and clinical follow-up of patients operated on for subcutaneous rupture of the Achilles tendon].

    PubMed

    Cinotti, A; Massari, L; Traina, G C; Mannella, P

    1996-01-01

    Thanks to its good long-term results, surgery is the method of choice to treat subcutaneous ruptures of the Achilles tendon. Reconstructed tendons present typical morphological and functional US patterns which depend partly on the kind of surgical reconstruction and partly on the time passed since surgery. The authors report the results of the clinical and US follow-up of a series of 62 surgical patients treated in 7 years for the subcutaneous rupture of the Achilles tendon. The patients were 55 men and 7 women, whose mean age was 36 years (range: 25-65 years). The left-hand side was affected in 38 patients and the right-hand side in 24 patients. All patients were operated on using an end-to-end suture and reinforcement plastic surgery pulling down a gastrocnemius tendon flap. To homogenize the results, all the US exams were performed by the same operator, in the presence of the orthopedic specialist and under the same conditions: both the involved and the contralateral Achilles tendons were studied, longitudinal and transverse scans were performed with the foot in max. plantar and dorsal flexion and, whenever possible, dynamic scans were also performed making the sural triceps contract against resistance. The following parameters were studied clinically: pain (which was absent in 39 patients, occasional in 11, after stress in 9 and on walking in 3 patients), skin scar trophism (which was eutrophic in 53.23% of patients, keloid in 27.42% and hypertrophic in 19.35% of patients), ankle joint excursion (plantar flexion was impaired in 32.3% and dorsal flexion in 36% of patients), walking on tiptoe (in all, 22.6% of patients complained of difficulties walking on tiptoe) and, finally, work activity resumption (which all patients achieved). US depicted the surgical tendons as much bigger than the contralateral ones (3-4 times on the average), which increase in volume lasted throughout the follow-up. In 75% of patients the echo structure of the surgical tendons was

  3. Zone III flexor tendon injuries - A proposed modification to rehabilitation.

    PubMed

    Chinchalkar, Shrikant J; Pipicelli, Joey G; Agur, Anne; Athwal, George S

    2015-01-01

    In this manuscript, these authors have utilized years of clinical experience to suggest rehabilitation modifications for Zone III flexor tendon injuries. - VictoriaPriganc, PhD, OTR, CHT, CLT, Practice Forum Editor.

  4. [Achilles tendon xanthoma imaging on ultrasound and magnetic resonance imaging].

    PubMed

    Fernandes, Eloy de Ávila; Santos, Eduardo Henrique Sena; Tucunduva, Tatiana Cardoso de Mello; Ferrari, Antonio J L; Fernandes, Artur da Rocha Correa

    2015-01-01

    The Achilles tendon xanthoma is a rare disease and has a high association with primary hyperlipidemia. An early diagnosis is essential to start treatment and change the disease course. Imaging exams can enhance diagnosis. This study reports the case of a 60-year-old man having painless nodules on his elbows and Achilles tendons without typical gout crisis, followed in the microcrystalline disease clinic of Unifesp for diagnostic workup. Laboratory tests obtained showed dyslipidemia. The ultrasound (US) showed a diffuse Achilles tendon thickening with hypoechoic areas. Magnetic resonance imaging (MRI) showed a diffuse tendon thickening with intermediate signal areas, and a reticulate pattern within. Imaging studies showed relevant aspects to diagnose a xanthoma, thus helping in the differential diagnosis.

  5. 21 CFR 888.3025 - Passive tendon prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) Identification. A passive tendon prosthesis is a device intended to be implanted made of silicon elastomer or a polyester reinforced medical grade silicone elastomer intended for use in the surgical reconstruction of...

  6. 21 CFR 888.3025 - Passive tendon prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...) Identification. A passive tendon prosthesis is a device intended to be implanted made of silicon elastomer or a polyester reinforced medical grade silicone elastomer intended for use in the surgical reconstruction of...

  7. Fibrous Tendon Hypertrophy after Gastrocnemius Recession: A Case Report.

    PubMed

    Jastifer, James R; Coughlin, Michael J

    2016-01-01

    Surgical complications after gastrocnemius recession have been rare in published studies. We report a case of symptomatic fibrous tendon hypertrophy requiring revision surgery. Additionally, we have provided a review of the published data on the complications related to this procedure.

  8. Vascularized dorsal digital fascial flap improves flexor tendon repairs.

    PubMed

    Sun, L-Q; Zhao, G; Gao, S-H; Chen, C

    2014-09-01

    We report a new method of flexor tendon repair in zone II using a standard modified Kessler technique combined with a vascularized dorsal fascial flap from the finger pedicled on a dorsal cutaneous branch of the proper digital artery, which is placed as a mechanical barrier between the flexor digitorum superficialis and profundus tendons. The functional outcomes of 14 patients (Group A) with flexor tendon repairs in zone II by this new technique were compared with those of 32 patients (Group B) with flexor tendon repairs in zone II using a standard modified Kessler technique only. Patients in Group A had a higher proportion of excellent results (on the modified Strickland system) and more movement in the distal interphalangeal joint than the patients in Group B.

  9. Nonlinear optical imaging characteristics in rat tail tendon

    NASA Astrophysics Data System (ADS)

    Liu, N. R.; Zhang, X. Z.; Qiu, Y. S.; Chen, R.

    2013-04-01

    The aim of this study was to examine the characteristics of skeletal muscle fibers in tail tendons, explore the content of intrinsic components at different depths and ascertain the optimum excitation wavelength, which will help to establish a relationship between diagnosis and therapy and the tendon injury. A multiphoton microscopic imaging system was used to achieve the images and spectra via an imaging mode and a Lambda mode, respectively. This work demonstrates that the skeletal muscle fibers of the tail tendon are in good order. Second harmonic generation (SHG) and two-photon excited fluorescence (TPEF) signals originating from certain intrinsic components are varied with depth, and the SHG/TPEF intensity ratios are varied at different excitation wavelengths. Below 800 nm is the optimum for cell TPEF, while above 800 nm is the optimum for SHG. With the development of imaging techniques, a nonlinear optical imaging system will be helpful to represent the functional behaviors of tissue related to tendon injury.

  10. The flexor tendon pulley system and rock climbing.

    PubMed

    Crowley, Timothy P

    2012-06-01

    Rock climbing has increased in popularity over the past two decades. Closed traumatic rupture of the finger flexor tendon pulleys is rare among the general population but is seen much more commonly in rock climbers. This article reviews the anatomy and biomechanics of the finger flexor tendon pulleys, how they may be injured in rock climbing and how these injuries are best diagnosed and managed.

  11. Direct Repair without Augmentation of Patellar Tendon Avulsion following TKA

    PubMed Central

    Kumar, Nishikant; Yadav, Chandrashekhar; Kumar, Ashok

    2015-01-01

    Complications involving the extensor mechanism after TKA are potentially disastrous. We are reporting a case of patellar tendon rupture from tibial tuberosity following total knee arthroplasty. We managed it by direct repair with fiberwire using Krackow suture technique without augmentation. Our long term result has been very encouraging. Our method is a safe and better method of management of patellar tendon avulsion following TKA when it happens without any tissue loss. PMID:25632362

  12. Closed rupture of the flexor tendons caused by carpal bone and joint disorders.

    PubMed

    Yamazaki, H; Kato, H; Hata, Y; Nakatsuchi, Y; Tsuchikane, A

    2007-12-01

    We analysed 21 patients with closed rupture of the flexor tendons caused by carpal bone and joint disorders. The tendon that ruptured depended on the location of the bone perforation into the carpal tunnel. Radiocarpal arthrography was performed in 13 patients and capsular perforation was demonstrated by contrast medium leakage into the carpal canal in 11 patients. This proved a useful diagnostic test. The flexor tendon(s) were reconstructed with free tendon graft in 17 patients, cross-over transfer of flexor tendons from adjacent digits in two and buddying to an adjacent flexor tendon in one patient. Postoperative total active range of motion in the fingers after 13 free tendon graft reconstructions averaged 213 degrees (range 170-265 degrees ). The active range of motion of the thumb-interphalangeal joint after free tendon graft reconstruction in three cases improved from 0 degrees to 33 degrees on average (range 10 degrees -40 degrees ).

  13. Tendon Extracellular Matrix Alterations in Ullrich Congenital Muscular Dystrophy

    PubMed Central

    Sardone, Francesca; Traina, Francesco; Bondi, Alice; Merlini, Luciano; Santi, Spartaco; Maraldi, Nadir Mario; Faldini, Cesare; Sabatelli, Patrizia

    2016-01-01

    Collagen VI (COLVI) is a non-fibrillar collagen expressed in skeletal muscle and most connective tissues. Mutations in COLVI genes cause two major clinical forms, Bethlem myopathy and Ullrich congenital muscular dystrophy (UCMD). In addition to congenital muscle weakness, patients affected by COLVI myopathies show axial and proximal joint contractures and distal joint hypermobility, which suggest the involvement of the tendon function. We examined a peroneal tendon biopsy and tenocyte culture of a 15-year-old patient affected by UCMD with compound heterozygous COL6A2 mutations. In patient’s tendon biopsy, we found striking morphological alterations of tendon fibrils, consisting in irregular profiles and reduced mean diameter. The organization of the pericellular matrix of tenocytes, the primary site of collagen fibril assembly, was severely affected, as determined by immunoelectron microscopy, which showed an abnormal accumulation of COLVI and altered distribution of collagen I (COLI) and fibronectin (FBN). In patient’s tenocyte culture, COLVI web formation and cell surface association were severely impaired; large aggregates of COLVI, which matched with COLI labeling, were frequently detected in the extracellular matrix. In addition, metalloproteinase MMP-2, an extracellular matrix-regulating enzyme, was increased in the conditioned medium of patient’s tenocytes, as determined by gelatin zymography and western blot. Altogether, these data indicate that COLVI deficiency may influence the organization of UCMD tendon matrix, resulting in dysfunctional fibrillogenesis. The alterations of tendon matrix may contribute to the complex pathogenesis of COLVI related myopathies. PMID:27375477

  14. The junctura lasso: correction of extensor tendon displacement.

    PubMed

    Yong, Chin Chean; Connolly, Cara M; Erdmann, Matt

    2013-11-01

    Recurrent volar displacement of the extensor digitorum communis tendon (EDC) at the metacarpophalangeal joint (MCPJ) more commonly occurs post-trauma or in the rheumatoid hand. This disabling condition of the hand results in painful swelling of the MCPJ, associated with "locking" of the extensor tendon. We report a simple surgical technique used to successfully 'secure' the EDC from recurrent displacement. This was performed for a 59-year-old man who developed the condition in his ring finger, following Vth ray amputation for severe Dupuytren's disease. First, the EDC over the IIIrd and IVth MCPJ are exposed using a longitudinal incision. The junctura tendinum between the EDC tendons was next extended proximally by 2 cm on the radial side of the IVth EDC and then divided to create a distally based junctura slip. Next, a 'lasso' was created by passing the slip beneath the IVth EDC tendon and then securing it onto itself with a 5/0 Ethibond suture (Ethicon Inc.). This reconstruction was then tested in all ranges of MCPJ flexion, successfully preventing volar displacement of the extensor tendon. The 'junctura lasso' provided a satisfactory solution for the patient, who, over the next four years; for the duration of his follow-up, suffered no further displacement of the extensor tendon.

  15. Tendon Extracellular Matrix Alterations in Ullrich Congenital Muscular Dystrophy.

    PubMed

    Sardone, Francesca; Traina, Francesco; Bondi, Alice; Merlini, Luciano; Santi, Spartaco; Maraldi, Nadir Mario; Faldini, Cesare; Sabatelli, Patrizia

    2016-01-01

    Collagen VI (COLVI) is a non-fibrillar collagen expressed in skeletal muscle and most connective tissues. Mutations in COLVI genes cause two major clinical forms, Bethlem myopathy and Ullrich congenital muscular dystrophy (UCMD). In addition to congenital muscle weakness, patients affected by COLVI myopathies show axial and proximal joint contractures and distal joint hypermobility, which suggest the involvement of the tendon function. We examined a peroneal tendon biopsy and tenocyte culture of a 15-year-old patient affected by UCMD with compound heterozygous COL6A2 mutations. In patient's tendon biopsy, we found striking morphological alterations of tendon fibrils, consisting in irregular profiles and reduced mean diameter. The organization of the pericellular matrix of tenocytes, the primary site of collagen fibril assembly, was severely affected, as determined by immunoelectron microscopy, which showed an abnormal accumulation of COLVI and altered distribution of collagen I (COLI) and fibronectin (FBN). In patient's tenocyte culture, COLVI web formation and cell surface association were severely impaired; large aggregates of COLVI, which matched with COLI labeling, were frequently detected in the extracellular matrix. In addition, metalloproteinase MMP-2, an extracellular matrix-regulating enzyme, was increased in the conditioned medium of patient's tenocytes, as determined by gelatin zymography and western blot. Altogether, these data indicate that COLVI deficiency may influence the organization of UCMD tendon matrix, resulting in dysfunctional fibrillogenesis. The alterations of tendon matrix may contribute to the complex pathogenesis of COLVI related myopathies.

  16. Tendon tissue engineering: progress, challenges, and translation to the clinic.

    PubMed

    Shearn, J T; Kinneberg, K R; Dyment, N A; Galloway, M T; Kenter, K; Wylie, C; Butler, D L

    2011-06-01

    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.

  17. Biomechanical Study of Two Peripheral Suture Methods on Repaired Tendons

    PubMed Central

    Qiu, Zhenling

    2015-01-01

    Flexor digitorum tendon injuries are challenging conditions to manage to ensure optimal patient outcomes. While several surgical approaches with high success rates have been developed, there remains no gold standard for suture technique for the repair of flexor tendon injuries. In this study, we compared two distinct peripheral suture methods on the strength of repaired tendons. Pig flexor digitorum profundus tendons were used in biomechanical studies and the biomechanical influence on tendon repair of continuous running peripheral suture (CRPS) and continuous locking peripheral suture (CLPS), were compared, using stitch length ranging from 1mm to 5mm. In CRPS, the 1mm stitch length group displayed the highest maximum load and breaking power, which was 1.57 fold higher than the 2mm stitch length group. Pairwise comparison revealed that the 1 and 2mm groups were statistically different from the 3, 4, and 5mm stitch length groups while comparison among the latter groups was not statistically significant. For CLPS, the 1mm group exhibited consistently the highest maximum load strength and breaking power, which was twice the strength displayed by the 2mm group. Pairwise comparisons between groups showed statistical significance. For future repairs of flexor tendon injuries, 1mm stitch length is highly recommended for simple peripheral suture.

  18. Substantial creep in healing human Achilles tendons. A pilot study

    PubMed Central

    Aspenberg, Per; Schepull, Thorsten

    2015-01-01

    Summary Background healing after rupture of the Achilles tendon can be described in terms of mechanical properties of the new-formed tissue, constituting the tendon callus. In previous human studies, the elastic modulus and the density remained almost constant during 3 months after mobilization started, and then improved up to one year. So far, time-dependent deformation of the healing human tendon has not been reported. Methods in a series of 16 patients, operated with Achilles tendon suture, we implanted tantalum beads into the tendon and measured the distance between them repeatedly during 3 min of constant loading, using an ordinary image intensifier. The patients unloaded their leg for 30 min before the test. To avoid bias, all images were investigated in a randomized and blinded order. Results total strain during 3 min of constant loading at 7 weeks post injury amounted to 5%, and at 19 weeks to 3%. About half of the strain, after the loading was applied, occurred during the second and third min. Considerable strain also occurred just before loading, when the patient was told that a load would be applied, but before this was actually done. Conclusion the measurements were crude, and this study should be seen as a pilot. Still, visco-elastic properties seem to dominate the mechanical behavior the healing Achilles tendon from start of mobilization to 19 weeks, at least when tested after 30 min rest. This deserves further studies with more precise methods. PMID:26605187

  19. 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

  20. Biomimetic scaffold design for functional and integrative tendon repair.

    PubMed

    Zhang, Xinzhi; Bogdanowicz, Danielle; Erisken, Cevat; Lee, Nancy M; Lu, Helen H

    2012-02-01

    Rotator cuff tears represent the most common shoulder injuries in the United States. The debilitating effect of this degenerative condition coupled with the high incidence of failure associated with existing graft choices underscores the clinical need for alternative grafting solutions. The 2 critical design criteria for the ideal tendon graft would require the graft to not only exhibit physiologically relevant mechanical properties but also be able to facilitate functional graft integration by promoting the regeneration of the native tendon-to-bone interface. Centered on these design goals, this review will highlight current approaches to functional and integrative tendon repair. In particular, the application of biomimetic design principles through the use of nanofiber- and nanocomposite-based scaffolds for tendon tissue engineering will be discussed. This review will begin with nanofiber-based approaches to functional tendon repair, followed by a section highlighting the exciting research on tendon-to-bone interface regeneration, with an emphasis on implementation of strategic biomimicry in nanofiber scaffold design and the concomitant formation of graded multi-tissue systems for integrative soft-tissue repair. This review will conclude with a summary and discussion of future directions.

  1. Strain and elongation of the human semitendinosus muscle - tendon unit.

    PubMed

    Kellis, Eleftherios; Patsika, Glykeria; Karagiannidis, Evaggelos

    2013-12-01

    The semitendinosus (ST) consists of a long distal tendon and it is divided in two parts by a tendinous inscription (TI). The purpose of this study was to quantify strain and elongation of the TI and the distal tendon of ST. Fourteen subjects performed ramp isometric contractions of the knee flexors at 0°, 45° and 90° of knee flexion. Two ultrasound probes were used to visualize the displacement of the distal tendon and selected points across the TI and aponeuroses. Three-way analysis of variance designs indicated that: (a) strain and elongation of the ST distal muscle-tendon junction were higher than that of the aponeurosis - TI junction points (p < 0.05) (b) the long arm of the TI reach strain of 49.86 ± 7.77% which was significantly (p < 0.05) higher than that displayed by the short arm (28.35 ± 0.59%) (c) Strain of tendinous and TI-aponeuroses segments significantly increased from 90° to 0° of knee flexion while the inverse was observed for the TI arm length (p < 0.05). (d) Tendon strain was significantly higher than strain of the TI-aponeuroses segments at 45° and 90° of knee flexion while the opposite was observed at 0° of knee flexion. The arrangement of TI along ST length results in differential local strains, indicating that the mechanical properties of the ST muscle are affected by tendon, aponeuroses and tendinous inscription interactions.

  2. Traumatic closed index extensor tendon rupture at the musclotendinous junction: a report of two cases.

    PubMed

    Komura, Shingo; Yokoi, Tatsuo; Nonomura, Hidehiko

    2011-03-01

    This report describes two cases of traumatic closed index extensor tendon rupture at the musclotendinous junction. Both patients were injured when their work gloves were caught in the revolving parts of machines, and both were treated surgically. One of the patients completely ruptured the index extensor digitorum communis (EDC) and the extensor indicis proprius (EIP) tendons at the musclotendinous junction of dorsal forearm. In this patient, the distal stump of the index EDC tendon was sutured to the middle EDC tendon in an end-to-side juncture. The other patient completely ruptured the EIP tendon and partially ruptured the index EDC tendon at the musclotendinous junction. In this patient, tendon transfer of the extensor digiti minimi (EDM) to the EIP tendon and plication of the index EDC tendon were performed. In both cases, surgical intervention enabled the patients to extend their index fingers almost normally; however, the former complained of inability to extend his index finger independently. Tendon transfer of the EDM in cases of index extensor tendon rupture at the musclotendinous junction is a good method to restore ability to independently extend the index finger. However, consideration should be given to anatomical variation in the little finger. The EDC tendon is sometimes absent leaving the EDM tendon as the only extensor tendon to the little finger.

  3. Giant cell tumour of tendon sheath with simultaneous two tendon involvement of the foot treated with excision of the tumour and reconstruction of the flexor retinaculum using tibialis posterior tendon in a paediatric patient: A rare case report.

    PubMed

    Tiwari, Vivek; Ansari, Tahir; Mittal, Samarth; Sharma, Pankaj; Nalwa, Aasma

    2015-12-01

    Giant cell tumour of tendon sheath is a benign soft tissue tumour arising from the tendon sheath. The involvement of foot and ankle by such tumours is relatively rare. Children are not commonly afflicted by this condition. All such tumours are reported to arise either from a single tendon sheath or one joint. We report a case of giant cell tumour of tendon sheath in a 12-year-old child, arising simultaneously from the tendon sheaths of tibialis posterior and flexor digitorum longus tendons, as well as extending into the ankle joint. It was treated by complete excision of the mass along with the tendon sheaths with reconstruction of the flexor retinaculum. The location of the tumour, age of the patient, diffuse nature of the tumour and novel technique of reconstruction of the flexor retinaculum make this case extremely rare and the first to be reported in literature.

  4. Review of inservice inspections of greased tendons in prestressed-concrete containments. [PWR; BWR

    SciTech Connect

    Dougan, J.R.; Ashar, H.

    1983-01-01

    Prestressed-concrete containments in the United States using greased prestressing tendons are inspected periodically to ensure structural integrity and to identify and correct problem areas before they become critical. An analysis of the available utility inspection data and an evaluation of the current and proposed guidelines were conducted to provide a measure of the reliability of the inspection process. Comments from utility and industry personnel were factored into the analysis. The results indicated that the majority of the few incidences of problems or abnormalities which occurred were minor in nature and did not threaten the structural integrity of the containment.

  5. Role of extracellular matrix in adaptation of tendon and skeletal muscle to mechanical loading.

    PubMed

    Kjaer, Michael

    2004-04-01

    The extracellular matrix (ECM), and especially the connective tissue with its collagen, links tissues of the body together and plays an important role in the force transmission and tissue structure maintenance especially in tendons, ligaments, bone, and muscle. The ECM turnover is influenced by physical activity, and both collagen synthesis and degrading metalloprotease enzymes increase with mechanical loading. Both transcription and posttranslational modifications, as well as local and systemic release of growth factors, are enhanced following exercise. For tendons, metabolic activity, circulatory responses, and collagen turnover are demonstrated to be more pronounced in humans than hitherto thought. Conversely, inactivity markedly decreases collagen turnover in both tendon and muscle. Chronic loading in the form of physical training leads both to increased collagen turnover as well as, dependent on the type of collagen in question, some degree of net collagen synthesis. These changes will modify the mechanical properties and the viscoelastic characteristics of the tissue, decrease its stress, and likely make it more load resistant. Cross-linking in connective tissue involves an intimate, enzymatical interplay between collagen synthesis and ECM proteoglycan components during growth and maturation and influences the collagen-derived functional properties of the tissue. With aging, glycation contributes to additional cross-linking which modifies tissue stiffness. Physiological signaling pathways from mechanical loading to changes in ECM most likely involve feedback signaling that results in rapid alterations in the mechanical properties of the ECM. In developing skeletal muscle, an important interplay between muscle cells and the ECM is present, and some evidence from adult human muscle suggests common signaling pathways to stimulate contractile and ECM components. Unaccostumed overloading responses suggest an important role of ECM in the adaptation of myofibrillar

  6. Low recurrence rate after mini surgery outside the tendon combined with short rehabilitation in patients with midportion Achilles tendinopathy

    PubMed Central

    Alfredson, Håkan

    2016-01-01

    Background There is a general opinion that a structured and specific rehabilitation is needed after treatment of midportion Achilles tendinopathy to minimize recurrence of the condition. There is sparse knowledge about the recurrence rates in large patient materials after specific treatments for midportion Achilles tendinopathy. Aim This study aimed to investigate the recurrence rates in a large number of patients with chronic painful midportion Achilles tendinopathy that had been surgically treated with the ultrasound (US) and Doppler (DP)-guided mini-surgical scraping technique. Postoperatively, a relatively simple rehabilitation protocol, including a range of movement exercises and gradually increased walking and biking before allowing free activity, was used. Materials and methods From a database, information about the recurrence rates after US + DP-guided mini-surgical scraping, performed by a single surgeon on 519 tendons with US + DP-verified chronic painful midportion Achilles tendinopathy, was obtained. Results Recurrence of painful midportion Achilles tendinopathy was found in 26 of 519 (5%) operated tendons, 13 from women and 13 from men. In 13 tendons, a close by located plantaris tendon was extirpated during the reoperation. Conclusion In this large material on patients treated with US + DP-guided mini-surgical scraping for midportion Achilles tendinopathy, there were few recurrences, although only a simple and nonspecific rehabilitation protocol was used. PMID:27274323

  7. Differential strain patterns of the human Achilles tendon determined in vivo with freehand three-dimensional ultrasound imaging.

    PubMed

    Farris, Dominic James; Trewartha, Grant; McGuigan, M Polly; Lichtwark, Glen A

    2013-02-15

    The human Achilles tendon (AT) has often been considered to act as a single elastic structure in series with the muscles of the triceps surae. As such it has been commonly modelled as a Hookean spring of uniform stiffness. However, the free AT and the proximal AT have distinctly different structures that lend themselves to different elastic properties. This study aimed to use three-dimensional freehand ultrasound imaging to determine whether the proximal AT and the free AT exhibit different elastic behaviour during sub-maximal, fixed-end contractions of the triceps surae. Six male and five female participants (mean ± s.d. age=27 ± 5 years) performed fixed position contractions of the plantar-flexors on an isokinetic dynamometer at 50% of their maximum voluntary contraction in this position. Freehand three-dimensional ultrasound imaging was used to reconstruct the free-tendon and proximal AT at rest and during contraction. The free-tendon exhibited significantly (P=0.03) greater longitudinal strain (5.2 ± 1.7%) than the proximal AT (2.6 ± 2.0%). The lesser longitudinal strain of the proximal AT was linked to the fact that it exhibited considerable transverse (orthogonal to the longitudinal direction) strains (5.0 ± 4%). The transverse strain of the proximal AT is likely due to the triceps surae muscles bulging upon contraction, and thus the level of bulging may influence the elastic behaviour of the proximal AT. This might have implications for the understanding of triceps surae muscle-tendon interaction during locomotion, tendon injury mechanics and previous measurements of AT elastic properties.

  8. Latissimus Dorsi Tendon Transfer with GraftJacket® Augmentation to Increase Tendon Length for an Irreparable Rotator Cuff Tear

    PubMed Central

    2017-01-01

    Massive irreparable rotator cuff tears can be reconstructed with latissimus dorsi tendon transfers (LDTT). Although uncommon, the natural length of the latissimus dorsi tendon (LDT) could be insufficient for transfer even after adequate soft tissue releases. Descriptions of cases where grafts were needed to lengthen the LDT are therefore rare. We located only two reports of the use of an acellular dermal matrix to increase effective tendon length in tendon transfers about the shoulder: (1) GraftJacket patch for a pectoralis major tendon reconstruction and (2) ArthroFlex® patch for LDTT. Both of these brands of allograft patches are obtained from human cadavers. These products are usually used to cover soft tissue repairs and offer supplemental support rather than for increasing tendon length. Extending the LDTT with GraftJacket to achieve adequate length, to our knowledge, has not been reported in the literature. We report the case of a 50-year-old male who had a massive, irreparable left shoulder rotator cuff tear that was reconstructed with a LDTT. The natural length of his LDT was insufficient for transfer. This unexpected situation was rectified by sewing two patches of GraftJacket to the LDT. The patient had greatly improved shoulder function at two-year follow-up. PMID:28194290

  9. Radiostereometric Evaluation of Tendon Elongation After Distal Biceps Repair

    PubMed Central

    Marshall, Nathan E.; Keller, Robert A.; Okoroha, Kelechi; Guest, John Michael; Yu, Charles; Muh, Stephanie; Moutzouros, Vasilios

    2016-01-01

    Background: Operative repair of distal biceps tendon ruptures has shown successful outcomes. However, little is known about the amount of tendon or repair site lengthening after repair. Purpose/Hypothesis: The purpose of this study was to evaluate distal biceps tendon repair via intratendinous radiostereometric analysis to analyze tendon lengthening at different time intervals of healing. The hypothesis was that there is significant lengthening after repair. Study Design: Case series; Level of evidence, 4. Methods: Eleven patients with distal biceps ruptures requiring operative repair were recruited. During repair, two 2-mm tantalum beads with laser-etched holes were sutured to the distal biceps tendon. Beads were evaluated via computed tomography scans immediately postoperatively and at 16 weeks. Radiographs were obtained at time 0 and then at 4, 8, and 16 weeks postoperatively. Measurements were made using the button-to-bead and bead-to-bead distances to assess repair site elongation as well as tendon elongation over time. After final follow-up, patients filled out the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire and underwent ultrasound to confirm the integrity of the tendon. Results: Ten patients had complete ruptures, with 1 having a partial rupture that underwent completion of the tear and subsequent repair. All patients showed statistically significant lengthening after surgery. The mean amount of tendon lengthening after surgery was 22.8 mm (range, 11.2-30.9 mm; P < .05), and the repair site lengthened a mean 17.0 mm (range, 9.6-30.6 mm; P < .05) from surgery to final follow-up. The greatest change in lengthening was noted between time 0 and week 4 (mean, 11.3 mm; P < .05), with the least amount of lengthening between weeks 8 and 16 (mean, 2.6 mm; P < .05). The mean DASH score was 11.2. Final ultrasound evaluations found all tendons to be in continuity. Conclusion: All patients undergoing distal biceps tendon repair have significant

  10. Allometry of the Tendon Enthesis: Mechanisms of Load Transfer Between Tendon and Bone

    PubMed Central

    Deymier-Black, Alix C.; Pasteris, Jill D.; Genin, Guy M.; Thomopoulos, Stavros

    2015-01-01

    Several features of the tendon-to-bone attachment were examined allometrically to determine load transfer mechanisms. The humeral head diameter increased geometrically with animal mass. Area of the attachment site exhibited a near isometric increase with muscle physiological cross section. In contrast, the interfacial roughness as well as the mineral gradient width demonstrated a hypoallometric relationship with physiologic cross-sectional area (PCSA). The isometric increase in attachment area indicates that as muscle forces increase, the attachment area increases accordingly, thus maintaining a constant interfacial stress. Due to the presence of constant stresses at the attachment, the micrometer-scale features may not need to vary with increasing load. PMID:26355607

  11. Evaluation of Elastic Stiffness in Healing Achilles Tendon After Surgical Repair of a Tendon Rupture Using In Vivo Ultrasound Shear Wave Elastography

    PubMed Central

    Zhang, Li-ning; Wan, Wen-bo; Wang, Yue-xiang; Jiao, Zi-yu; Zhang, Li-hai; Luo, Yu-kun; Tang, Pei-fu

    2016-01-01

    Background There has been no published report assessing the mechanical properties of a repaired Achilles tendon after surgery using shear wave elastography (SWE). The aim of this study was to investigate the changes in mechanical properties of the healing Achilles tendon after surgical repair of a tendon rupture using ultrasound SWE and how these changes correlate with tendon function. Material/Methods Twenty-six patients who underwent surgical repair for Achilles tendon rupture were examined with ultrasound SWE coupled with a linear array transducer (4–15 MHz). The elasticity values of the repaired Achilles tendon in a longitudinal view were measured at 12, 24, and 48 weeks postoperatively. Functional outcomes were assessed with the American Orthopedic Foot and Ankle Society (AOFAS) rating system at 12, 24, and 48 weeks postoperatively. General linear regression analysis and correlation coefficients were used to analyze the relationship between elasticity and the AOFAS score. Results There were significant differences with respect to the mean elasticity values and functional scores of the repaired Achilles tendon at 12, 24, and 48 weeks postoperatively (all P<0.05). Tendon function was positively correlated with the elasticity of the repaired Achilles tendon (P=0.0003). Conclusions Our findings suggest that SWE can provide biomechanical information for evaluating the mechanical properties of healing Achilles tendon and predict Achilles tendon function. PMID:27072885

  12. Production of PGE(2) increases in tendons subjected to repetitive mechanical loading and induces differentiation of tendon stem cells into non-tenocytes.

    PubMed

    Zhang, Jianying; Wang, James H-C

    2010-02-01

    Whether tendon inflammation is involved in the development of tendinopathy or degenerative changes of the tendon remains a matter of debate. We explored this question by performing animal and cell culture experiments to determine the production and effects of PGE(2), a major inflammatory mediator in tendons. Mouse tendons were subjected to repetitive mechanical loading via treadmill running, and the effect of PGE(2) on proliferation and differentiation of tendon stem cells (TSCs) was assessed in vitro. Compared to levels in cage control mice, PGE(2) levels in mouse patellar and Achilles tendons were markedly increased in response to a bout of rigorous treadmill running. PGE(2) treatment of TSCs in culture decreased cell proliferation and induced both adipogenesis and osteogenesis of TSCs, as evidenced by accumulation of lipid droplets and calcium deposits, respectively. Effects of PGE(2) on both TSC proliferation and differentiation were apparently PGE(2)-dose-dependent. These findings suggest that high levels of PGE(2), which are present in tendons subjected to repetitive mechanical loading conditions in vivo as shown in this study, may result in degenerative changes of the tendon by decreasing proliferation of TSCs in tendons and also inducing differentiation of TSCs into adipocytes and osteocytes. The consequences of this PGE(2) effect on TSCs is the reduction of the pool of tenocytes for repair of tendons injured by mechanical loading, and production of fatty and calcified tissues within the tendon, often seen at the later stages of tendinopathy.

  13. Effects of BMP-12-Releasing Sutures on Achilles Tendon Healing

    PubMed Central

    Chamberlain, Connie S.; Lee, Jae-Sung; Leiferman, Ellen M.; Maassen, Nicholas X.; Baer, Geoffrey S.

    2015-01-01

    Tendon healing is a complex coordinated event orchestrated by numerous biologically active proteins. Unfortunately, tendons have limited regenerative potential and as a result, repair may be protracted months to years. Current treatment strategies do not offer localized delivery of biologically active proteins, which may result in reduced therapeutic efficacy. Surgical sutures coated with nanostructured minerals may provide a potentially universal tool to efficiently incorporate and deliver biologically active proteins directly to the wound. Additionally, previous reports indicated that treatment with bone morphogenetic protein-12 (BMP-12) improved tendon healing. Based on this information, we hypothesized that mineral-coated surgical sutures may be an effective platform for localized BMP-12 delivery to an injured tendon. The objective of this study was, therefore, to elucidate the healing effects of mineral-coated sutures releasing BMP-12 using a rat Achilles healing model. The effects of BMP-12-releasing sutures were also compared with standard BMP-12 delivery methods, including delivery of BMP-12 through collagen sponge or direct injection. Rat Achilles tendons were unilaterally transected and repaired using BMP-12-releasing suture (0, 0.15, 1.5, or 3.0 μg), collagen sponge (0 or 1.5 μg BMP-12), or direct injection (0 or 1.5 μg). By 14 days postinjury, repair with BMP-12-releasing sutures reduced the appearance of adhesions to the tendon and decreased total cell numbers. BMP-12 released from sutures and collagen sponge also tended to improve collagen organization when compared with BMP-12 delivered through injection. Based on these results, the release of a protein from sutures was able to elicit a biological response. Furthermore, BMP-12-releasing sutures modulated tendon healing, and the delivery method dictated the response of the healing tissue to BMP-12. PMID:25354567

  14. Effects of celecoxib on proliferation and tenocytic differentiation of tendon-derived stem cells

    SciTech Connect

    Zhang, Kairui; Zhang, Sheng; Li, Qianqian; Yang, Jun; Dong, Weiqiang; Wang, Shengnan; Cheng, Yirong; Al-Qwbani, Mohammed; Wang, Qiang; Yu, Bin

    2014-07-18

    Highlights: • Celecoxib has no effects on TDSCs cell proliferation in various concentrations. • Celecoxib reduced mRNAs levels of tendon associated transcription factor. • Celecoxib reduced mRNAs levels of main tendon associated collagen. • Celecoxib reduced mRNAs levels of tendon associated molecules. - Abstract: NSAIDs are often ingested to reduce the pain and improve regeneration of tendon after tendon injury. Although the effects of NSAIDs in tendon healing have been reported, the data and conclusions are not consistent. Recently, tendon-derived stem cells (TDSCs) have been isolated from tendon tissues and has been suggested involved in tendon repair. Our study aims to determine the effects of COX-2 inhibitor (celecoxib) on the proliferation and tenocytic differentiation of TDSCs. TDSCs were isolated from mice Achilles tendon and exposed to celecoxib. Cell proliferation rate was investigated at various concentrations (0.1, 1, 10 and 100 μg/ml) of celecoxib by using hemocytometer. The mRNA expression of tendon associated transcription factors, tendon associated collagens and tendon associated molecules were determined by reverse transcription-polymerase chain reaction. The protein expression of Collagen I, Collagen III, Scleraxis and Tenomodulin were determined by Western blotting. The results showed that celecoxib has no effects on TDSCs cell proliferation in various concentrations (p > 0.05). The levels of most tendon associated transcription factors, tendon associated collagens and tendon associated molecules genes expression were significantly decreased in celecoxib (10 μg/ml) treated group (p < 0.05). Collagen I, Collagen III, Scleraxis and Tenomodulin protein expression were also significantly decreased in celecoxib (10 μg/ml) treated group (p < 0.05). In conclusion, celecoxib inhibits tenocytic differentiation of tendon-derived stem cells but has no effects on cell proliferation.

  15. Plantar fascia anatomy and its relationship with Achilles tendon and paratenon.

    PubMed

    Stecco, Carla; Corradin, Marco; Macchi, Veronica; Morra, Aldo; Porzionato, Andrea; Biz, Carlo; De Caro, Raffaele

    2013-12-01

    Although the plantar fascia (PF) has been studied quite well from a biomechanical viewpoint, its microscopic properties have been overlooked: nothing is known about its content of elastic fibers, the features of the extracellular matrix or the extent of innervation. From a functional and clinical standpoint, the PF is often correlated with the triceps surae muscle, but the anatomical grounds for this link are not clear. The aim of this work was to focus on the PF macroscopic and microscopic properties and study how Achilles tendon diseases might affect it. Twelve feet from unembalmed human cadavers were dissected to isolate the PF. Specimens from each PF were tested with various histological and immunohistochemical stains. In a second stage, 52 magnetic resonance images (MRI) obtained from patients complaining of aspecific ankle or foot pain were analyzed, dividing the cases into two groups based on the presence or absence of signs of degeneration and/or inflammation of the Achilles tendon. The thickness of PF and paratenon was assessed in the two groups and statistical analyses were conducted. The PF is a tissue firmly joined to plantar muscles and skin. Analyzing its possible connections to the sural structures showed that this fascia is more closely connected to the paratenon of Achilles tendon than to the Achilles tendon, through the periosteum of the heel. The PF extended medially and laterally, continuing into the deep fasciae enveloping the abductor hallucis and abductor digiti minimi muscles, respectively. The PF was rich in hyaluronan, probably produced by fibroblastic-like cells described as 'fasciacytes'. Nerve endings and Pacini and Ruffini corpuscles were present, particularly in the medial and lateral portions, and on the surface of the muscles, suggesting a role for the PF in the proprioception of foot. In the radiological study, 27 of the 52 MRI showed signs of Achilles tendon inflammation and/or degeneration, and the PF was 3.43 ± 0.48 mm thick

  16. Plantar fascia anatomy and its relationship with Achilles tendon and paratenon

    PubMed Central

    Stecco, Carla; Corradin, Marco; Macchi, Veronica; Morra, Aldo; Porzionato, Andrea; Biz, Carlo; De Caro, Raffaele

    2013-01-01

    Although the plantar fascia (PF) has been studied quite well from a biomechanical viewpoint, its microscopic properties have been overlooked: nothing is known about its content of elastic fibers, the features of the extracellular matrix or the extent of innervation. From a functional and clinical standpoint, the PF is often correlated with the triceps surae muscle, but the anatomical grounds for this link are not clear. The aim of this work was to focus on the PF macroscopic and microscopic properties and study how Achilles tendon diseases might affect it. Twelve feet from unembalmed human cadavers were dissected to isolate the PF. Specimens from each PF were tested with various histological and immunohistochemical stains. In a second stage, 52 magnetic resonance images (MRI) obtained from patients complaining of aspecific ankle or foot pain were analyzed, dividing the cases into two groups based on the presence or absence of signs of degeneration and/or inflammation of the Achilles tendon. The thickness of PF and paratenon was assessed in the two groups and statistical analyses were conducted. The PF is a tissue firmly joined to plantar muscles and skin. Analyzing its possible connections to the sural structures showed that this fascia is more closely connected to the paratenon of Achilles tendon than to the Achilles tendon, through the periosteum of the heel. The PF extended medially and laterally, continuing into the deep fasciae enveloping the abductor hallucis and abductor digiti minimi muscles, respectively. The PF was rich in hyaluronan, probably produced by fibroblastic-like cells described as ‘fasciacytes’. Nerve endings and Pacini and Ruffini corpuscles were present, particularly in the medial and lateral portions, and on the surface of the muscles, suggesting a role for the PF in the proprioception of foot. In the radiological study, 27 of the 52 MRI showed signs of Achilles tendon inflammation and/or degeneration, and the PF was 3.43 ± 0.48 mm

  17. In vivo tissue interaction between the transverse carpal ligament and finger flexor tendons.

    PubMed

    Gabra, Joseph N; Gordon, Joshua L; Marquardt, Tamara L; Li, Zong-Ming

    2016-10-01

    The transverse carpal ligament (TCL) is a component of the flexor pulley system of the wrist, keeping the flexor tendons in place by resisting their volar displacement. The purpose of this study was to investigate the in vivo biomechanical interaction between the TCL and flexor tendons in response to tendon tensioning with the wrist at various postures. In eight healthy subjects, the flexor digitorum superficialis and profundus tendons were tensioned by isometrically applying loads (5, 10, and 15N) to the index finger while the wrist posture was at 20° extension, neutral, 20° flexion, and 40° flexion. The TCL and flexor tendons were imaged at the distal carpal tunnel cross section using ultrasound. The volar-dorsal positions of the tendons, TCL arch height, and TCL-tendon distances were calculated. With increasing wrist flexion, the flexor tendons moved volarly, the TCL arch height increased, and the TCL-tendon distances decreased, indicating that the flexor tendons contacted the TCL and pushed it volarly. The TCL-tendon interaction was amplified by the combination of finger loading and wrist flexion. This study provides in vivo evidence of the biomechanical interaction between the TCL and flexor tendons. Repetitive TCL-tendon interactions may implicate the interacting tissues and the median nerve resulting in tissue maladaptation and nerve compression.

  18. Actin Cytoskeleton Contributes to the Elastic Modulus of Embryonic Tendon During Early Development

    PubMed Central

    Schiele, Nathan R.; von Flotow, Friedrich; Tochka, Zachary L.; Hockaday, Laura A.; Marturano, Joseph E.; Thibodeau, Jeffrey J.; Kuo, Catherine K.

    2016-01-01

    Tendon injuries are common and heal poorly. Strategies to regenerate or replace injured tendons are challenged by an incomplete understanding of normal tendon development. Our previous study showed that embryonic tendon elastic modulus increases as a function of developmental stage. Inhibition of enzymatic collagen crosslink formation abrogated increases in tendon elastic modulus at late developmental stages, but did not affect increases in elastic modulus of early stage embryonic tendons. Here, we aimed to identify potential contributors to the mechanical properties of these early stage embryonic tendons. We characterized tendon progenitor cells in early stage embryonic tendons, and the influence of actin cytoskeleton disruption on tissue elastic modulus. Cells were closely packed in embryonic tendons, and did not change in density during early development. We observed an organized network of actin filaments that seemed contiguous between adjacent cells. The actin filaments exhibited a crimp pattern with a period and amplitude that matched the crimp of collagen fibers at each developmental stage. Chemical disruption of the actin cytoskeleton decreased tendon tissue elastic modulus, measured by atomic force microscopy. Our results demonstrate that early developmental stage embryonic tendons possess a well organized actin cytoskeleton network that contributes significantly to tendon tissue mechanical properties. PMID:25721681

  19. Actin cytoskeleton contributes to the elastic modulus of embryonic tendon during early development.

    PubMed

    Schiele, Nathan R; von Flotow, Friedrich; Tochka, Zachary L; Hockaday, Laura A; Marturano, Joseph E; Thibodeau, Jeffrey J; Kuo, Catherine K

    2015-06-01

    Tendon injuries are common and heal poorly. Strategies to regenerate or replace injured tendons are challenged by an incomplete understanding of normal tendon development. Our previous study showed that embryonic tendon elastic modulus increases as a function of developmental stage. Inhibition of enzymatic collagen crosslink formation abrogated increases in tendon elastic modulus at late developmental stages, but did not affect increases in elastic modulus of early stage embryonic tendons. Here, we aimed to identify potential contributors to the mechanical properties of these early stage embryonic tendons. We characterized tendon progenitor cells in early stage embryonic tendons, and the influence of actin cytoskeleton disruption on tissue elastic modulus. Cells were closely packed in embryonic tendons, and did not change in density during early development. We observed an organized network of actin filaments that seemed contiguous between adjacent cells. The actin filaments exhibited a crimp pattern with a period and amplitude that matched the crimp of collagen fibers at each developmental stage. Chemical disruption of the actin cytoskeleton decreased tendon tissue elastic modulus, measured by atomic force microscopy. Our results demonstrate that early developmental stage embryonic tendons possess a well organized actin cytoskeleton network that contributes significantly to tendon tissue mechanical properties.

  20. Lateral epicondylalgia: midlife crisis of a tendon.

    PubMed

    Luk, James K H; Tsang, Raymond C C; Leung, H B

    2014-04-01

    The pathogenesis and management of lateral epicondylalgia, or tennis elbow, a common ailment affecting middle-aged subjects of both genders continue to provoke controversy. Currently it is thought to be due to local tendon pathology, pain system changes, and motor system impairment. Its diagnosis is usually clinical, based on a classical history, as well as symptoms and signs. In selected cases, additional imaging (X-rays, ultrasound, and magnetic resonance imaging) can help to confirm the diagnosis. Different treatment modalities have been described, including the use of orthotics, non-steroidal anti-inflammatory drugs, steroid injections, topical glyceryl trinitrate, exercise therapy, manual therapy, ultrasound therapy, laser therapy, extracorporeal shockwave therapy, acupuncture, taping, platelet-rich plasma injections, hyaluronan gel injections, botulinum toxin injections, and surgery. Nevertheless, evidence to select the best treatment is lacking and the choice of therapy depends on the experience of the management team, availability of the equipment and expertise, and patient response. This article provides a snapshot of current medical practice for lateral epicondylalgia management.

  1. [Functional analysis after Achilles tendon repair].

    PubMed

    Moretti, B; Quagliarella, L; Sasanelli, N; Garofalo, R; Moretti, L; Patella, S; Belgiovine, G; Patella, V

    2007-01-01

    The Achilles tendon rupture (ATR) is a severe injury and requires a surgical treatment which can result in functional impairment, limiting unprofessional sports activities. In order to evaluate this potential impairment 20 subjects (SG) who had received surgical treatment for ATR and 20 healthy subjects (CG) were required to execute vertical jump according to counter movement jump and squat jump protocol. For both groups the flying time (Tv) of each foot has been acquired, adopting accelerometric transducers positioned posteriorly at the level of malleolar axis. The SG's Tv is significantly lesser than the CG's one, demonstrating an inferior global performance respect to healthy people and the operated leg has a Tv 6% higher than the contralateral, while in the CG there are no statistical difference between the Tv of the limbs. For seven operated subjects Tv values are lesser than threshold values obtained from CG. For them sports activity which implies high and cyclic stress on the lower limbs could be dangerous. Functional evaluation, consequently, allow to assess impairments not differently estimable.

  2. Extended healing validation of an artificial tendon to connect the quadriceps muscle to the Tibia: 180-day study.

    PubMed

    Melvin, Alan J; Litsky, Alan S; Mayerson, Joel L; Stringer, Keith; Juncosa-Melvin, Natalia

    2012-07-01

    Whenever a tendon or its bone insertion is disrupted or removed, existing surgical techniques provide a temporary connection or scaffolding to promote healing, but the interface of living to non-living materials soon breaks down under the stress of these applications, if it must bear the load more than acutely. Patients are thus disabled whose prostheses, defect size, or mere anatomy limit the availability or outcomes of such treatments. Our group developed the OrthoCoupler™ device to join skeletal muscle to prosthetic or natural structures without this interface breakdown. In this study, the goat knee extensor mechanism (quadriceps tendon, patella, and patellar tendon) was removed from the right hind limb in 16 goats. The device connected the quadriceps muscle to a stainless steel bone plate on the tibia. Mechanical testing and histology specimens were collected from each operated leg and contralateral unoperated control legs at 180 days. Maximum forces in the operated leg (vs. unoperated) were 1,400 ± 93 N (vs. 1,179 ± 61 N), linear stiffnesses were 33 ± 3 N/mm (vs. 37 ± 4 N/mm), and elongations at failure were 92.1 ± 5.3 mm (vs. 68.4 ± 3.8 mm; mean ± SEM). Higher maximum forces (p = 0.02) and elongations at failure (p=0.008) of legs with the device versus unoperated controls were significant; linear stiffnesses were not (p=0.3). We believe this technology will yield improved procedures for clinical challenges in orthopedic oncology, revision arthroplasty, tendon transfer, and tendon injury reconstruction.

  3. Relationship between mechanical properties and pentosidine in tendon: effects of age, diet restriction, and aminoguanidine in broiler breeder hens.

    PubMed

    Iqbal, M; Kenney, P B; Al-Humadi, N H; Klandorf, H

    2000-09-01

    Nonenzymatic glycosylation contributes to the formation of crosslinks, which leads to the structural and functional deterioration of tissue protein. The accumulation of these crosslinks in tissue proteins has been implicated in the alteration of biomechanical properties of connective tissues. The objective of this study was to determine whether tendon breaking time (TBT) and tendon breaking strength (TBS) of the flexor perforans et perforatus digiti iii tendon were related to concentrations of pentosidine in tendons (Pt) of broiler breeder hens from 8 to 125 wk of age. In addition, effects of diet restriction (DR) and a crosslinking inhibitor, aminoguanidine (AG) on Pt, TBS, and TBT were determined. Female chicks (n = 450) were randomly assigned to four treatment groups immediately after hatch: ad libitum-fed (AL); diet-restricted (DR; 60% of AL); and AL and DR groups supplemented with 1.35 mg/kg BW per day AG in the feed (AL+AG and DR+AG, respectively). In AL hens, Pt increased with increasing age (P < or = 0.0001). Concurrently, an age-related parallel increase was found for TBS (P < or = 0.0001) and TBT (P < or = 0.0001). Rate of Pt accumulation was lower in DR (P < or = 0.001), TBS (P < or = 0.01), and TBT (P < or = 0.02) hens compared with AL hens. Concentration of Pt in the AL + AG group was lower (P < or = 0.0002) than in the AL group; TBS and TBT (P < or = 0.01) followed a similar pattern. Supplementation of DR with AG did not affect Pt, TBS, or TBT. The age-related increase in Pt and loss of elasticity in the tendon was retarded by diet restriction and AG.

  4. [Developments in suture techniques of hand flexor tendon injuries during the last fifteen years].

    PubMed

    Bíró, Vilmos

    2016-02-07

    In the reconstruction of hand flexor tendon injuries it is fundamental to select the best suture technique, which makes possible early, active postoperative mobilization and achievement of the best results. The author reviews the development of suture techniques of the flexor tendon injuries during the last fifteen years, and discusses experimental tendon reconstruction results as well as clinical outcomes. The author describes the importance of different tendon suture materials, the significance of the pulley system of the fingers, the stretching between the sutured tendon ends by tendon sutures and, finally, the importance of the moving course in the reconstructed tendon. He states, that the wide-range adoption of the discussed modern tendon sutures would be necessary for better postoperative results.

  5. 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

  6. Methods of Assessing Human Tendon Metabolism and Tissue Properties in Response to Changes in Mechanical Loading.

    PubMed

    Heinemeier, Katja M; Kjaer, Michael; Magnusson, S Peter

    2016-01-01

    In recent years a number of methodological developments have improved the opportunities to study human tendon. Microdialysis enables sampling of interstitial fluid in the peritendon tissue, while sampling of human tendon biopsies allows direct analysis of tendon tissue for gene- and protein expression as well as protein synthesis rate. Further the (14)C bomb-pulse method has provided data on long-term tissue turnover in human tendon. Non-invasive techniques allow measurement of tendon metabolism (positron emission tomography (PET)), tendon morphology (magnetic resonance imaging (MRI)), and tendon mechanical properties (ultrasonography combined with force measurement during movement). Finally, 3D cell cultures of human tendon cells provide the opportunity to investigate cell-matrix interactions in response to various interventions.

  7. Intratendinous Tophaceous Gout Imitating Patellar Tendonitis in an Athletic Man

    PubMed Central

    Gililland, Jeremy M.; Webber, Nicholas P.; Jones, Kevin B.; Randall, R. Lor; Aoki, Stephen K.

    2013-01-01

    Patellar tendon-related pain is common in the athletic patient. When it occurs in skeletally mature patients participating in running, jumping, or kicking sports, the diagnosis of jumper’s knee patellar tendonitis is usually made. If patellar tendon pain is associated with a mass, the differential diagnosis should be broadened to include crystalline arthropathy. This article presents a case of a highly athletic 45-year-old man with a history of gout, anterior knee pain, and an enlarging mass in the region of the patellar tendon. Conservative management failed, and an excisional biopsy found it to be an intra-tendinous gouty tophus. To our knowledge, only 1 report exists documenting a patellar tendon mass secondary to gout, and no case report exists documenting this problem in an athlete. The interplay between athletics and gout has not been well described. Despite the long-term protective nature of fitness, transient elevations in uric acid associated with athletic endeavors may contribute acutely to manifestations of gout in some athletes. Resultant intra- or extra-articular pathology may present as, and easily be mistaken for, a sports-related injury. Without appropriate medical management, tophaceous deposition may continue to occur and treatment of the resultant mass may require surgical intervention. PMID:21410111

  8. Regenerative biology of tendon: mechanisms for renewal and repair

    PubMed Central

    Dyment, Nathaniel A.; Galloway, Jenna L.

    2015-01-01

    Understanding the molecular and cellular mechanisms underlying tissue turnover and repair are essential towards addressing pathologies in aging, injury and disease. Each tissue has distinct means of maintaining homeostasis and healing after injury. For some, resident stem cell populations mediate both of these processes. These stem cells, by definition, are self renewing and give rise to all the differentiated cells of that tissue. However, not all organs fit with this traditional stem cell model of regeneration, and some do not appear to harbor somatic stem or progenitor cells capable of multilineage in vivo reconstitution. Despite recent progress in tendon progenitor cell research, our current knowledge of the mechanisms regulating tendon cell homeostasis and injury response is limited. Understanding the role of resident tendon cell populations is of great importance for regenerative medicine based approaches to tendon injuries and disease. The goal of this review is to bring to light our current knowledge regarding tendon progenitor cells and their role in tissue maintenance and repair. We will focus on pressing questions in the field and the new tools, including model systems, available to address them. PMID:26389023

  9. Spontaneous Flexor Tendon Rupture Due to Atraumatic Chronic Carpal Instability

    PubMed Central

    Miranda, B. H.; Cerovac, S.

    2014-01-01

    Background Spontaneous flexor tendon rupture is considered to be invariably associated with previous hand/wrist injury or systemic disease such as rheumatoid arthritis. Case Description A 54-year-old man presented with a 4-month history of mild ulnar wrist pain and spontaneous left little finger flexion loss in the absence of distant/recent trauma and systemic arthropathy. Surgical exploration confirmed a zone IV left little finger flexor digitorum profundus (FDP5) attritional rupture (100%), ring finger flexor digitorum profundus (FDP4) attenuation (40%) and a disrupted lunotriquetral ligament and volar-ulnar wrist capsule. Volar subluxation of the narrowed carpal tunnel resulted in flexor tendon attrition against the hamate hook. A side-to-side tendon transfer was performed along with a lunotriquetral ligament repair and temporary Kirschner wire fixation. At 6 months the patient had full active, synchronous flexion of the ring and little fingers and reduced wrist pain. Literature Review Traumatic flexor tendon ruptures have been reported following distal radius/hamate hook fractures, from carpal bone osteophytes, accessory carpal bones and intraosseous ganglia. Attritional ruptures caused by chronic, degenerative carpal pathology are less common. Clinical Relevance This case highlights an unusual cause of flexor tendon rupture due to chronic carpal instability. PMID:25032080

  10. An investigation of tendon sheathing filler migration into concrete

    SciTech Connect

    Naus, D.J.; Oland, C.B.

    1998-03-01

    During some of the inspections at nuclear power plants with prestressed concrete containments, it was observed that the containments has experienced leakage of the tendon sheathing filler (i.e., streaks). The objective of this activity was to provide an indication of the extent of tendon sheathing filler leakage into the concrete and its affects on concrete properties. Literature was reviewed and concrete core samples were obtained from the Trojan Nuclear Plant and tested. The literature primarily addressed effects of crude or lubricating oils that are known to cause concrete damage. However, these materials have significantly different characteristics relative to the materials used as tendon sheathing fillers. Examination and testing of the concrete cores indicated that the appearance of tendon sheathing filler on the concrete surface was due to leakage from the conduits and its subsequent migration through cracks that were present. Migration of the tendon sheathing filler was confined to the cracks and there was no perceptible movement into the concrete. Results of compressive strength testing indicated that the concrete quality was consistent in the containment and that the strength had increased over 40% in 25.4 years relative to the average compressive strength at 28-days age.

  11. Should we think about wrist extensor after flexor tendon repair?

    PubMed Central

    Ferreira, Aline M; Tanaka, Denise M; Barbosa, Rafael I; Marcolino, Alexandre M; Elui, Valeria MC; Mazzer, Nilton

    2013-01-01

    Objective: To evaluate the activity of wrist extensor muscle, correlating with wrist motion during gripping after flexor tendon repair. Design: Cross-sectional clinical measurement study. Setting: Laboratory for biomechanics and rehabilitation. Subjects: A total of 11 patients submitted to rehabilitation by early passive motion of the fingers with wrist flexion position were evaluated after 8 weeks of fingers flexor tendon repair and 11 healthy volunteers, all ranging from 20 to 37 years of age. Intervention: Volunteers performed an isometric standardized gripping task. Main measures: We used electrogoniometry to analyze wrist range of motion and surface electromyography, considering 100% maximum voluntary contraction to represent the amplitude of electromyographic activity of the extensor carpi radialis and flexor digitorum superficialis. Results: Patients with flexor tendon repair showed co-activation deficit between wrist extensor (extensor carpi radialis) and flexor finger muscles (flexor digitorum superficialis) during gripping in the intermediate phase of rehabilitation, despite some recovering mobility for wrist extension (p ≤ 0.05). A moderate correlation between range of motion and extensor carpi radialis was present only for injured group (r = 0.32). Total active motion score, which represents finger active excursion, was regular or poor in 65% of cases, all with nerve repair associated. Conclusion: Wrist extensors have an important synergist role at handgrip, although some imbalance can be present after flexor tendon repair. These preliminary findings suggest that emphasis could be directed to add synergistic wrist motion in rehabilitation protocols after flexor tendon repair. Future studies with early active rehabilitation are necessary. PMID:26770674

  12. Irreparable Rotator Cuff Tears: Restoring Joint Kinematics by Tendon Transfers

    PubMed Central

    Greenspoon, Joshua A.; Millett, Peter J.; Moulton, Samuel G.; Petri, Maximilian

    2016-01-01

    Background: Tendon transfers can be a surgical treatment option in managing younger, active patients with massive irreparable rotator cuff tears. The purpose of this article is to provide an overview of the use of tendon transfers to treat massive irreparable rotator cuff tears and to summarize clinical outcomes. Methods: A selective literature search was performed and personal surgical experiences are reported. Results: Latissimus dorsi transfers have been used for many years in the management of posterosuperior rotator cuff tears with good reported clinical outcomes. It can be transferred without or with the teres major (L’Episcopo technique). Many surgical techniques have been described for latissimus dorsi transfer including single incision, double incision, and arthroscopically assisted transfer. Transfer of the pectoralis major tendon is the most common tendon transfer procedure performed for anterosuperior rotator cuff deficiencies. Several surgical techniques have been described, however transfer of the pectoralis major beneath the coracoid process has been found to most closely replicate the force vector that is normally provided by the intact subscapularis. Conclusion: Tendon transfers can be used successfully in the management of younger patients with massive irreparable rotator cuff tears and minimal glenohumeral arthritis. Improvements in clinical outcomes scores and range of motion have been demonstrated. This can delay arthroplasty, which is of particular importance for younger patients with high functional demands. PMID:27708730

  13. Tendoscopy in stage I posterior tibial tendon dysfunction.

    PubMed

    Khazen, Gabriel; Khazen, Cesar

    2012-09-01

    Stage I PTTD was defined by Johnson and Strom as tenosynovitis or tendinitis whereby tendon length remains normal, there is no hindfoot deformity, and diagnosis is basically clinical, characterized by swelling and tenderness posterior to the medial malleolus. The PTT has a hypovascular zone 40 mm proximal to the insertion of the tendon and 14 mm in length. Pain often is localized to this portion of the tendon. Tendon power might be normal, and the patient can perform single heel rise, sometimes with slight discomfort. This condition is often misdiagnosed as ankle sprain, which delays correct diagnosis and early treatment that may improve symptoms, stop the disease process, and prevent the development of adult acquired flatfoot deformity. Ultrasonography is a valuable adjunctive diagnostic tool for stage I PTTD, but the authors always indicate MRI for accurate diagnosis in such patients. Patients with stage I PTTD are first treated nonoperatively with nonsteroidal anti-inflammatory drugs for 5 days, cryotherapy, local ultrasound, and a PTTD airlift brace (Aircast) for 3 to 6 months. If symptoms persist, surgical debridement and synovectomy has been suggested. PTT tendoscopic synovectomy is a minimally invasive and effective surgical procedure to treat patients with stage I PTTD. It has the advantages of less wound pain, and fewer scar and wound problems. If tendon tear is observed during tendoscopy, it must be repaired with nonabsorbable sutures using a 3- or 4-cm incision.

  14. Loss of Drosophila A-type lamin C initially causes tendon abnormality including disintegration of cytoskeleton and nuclear lamina in muscular defects.

    PubMed

    Uchino, Ryo; Nonaka, Yu-Ki; Horigome, Tuneyoshi; Sugiyama, Shin; Furukawa, Kazuhiro

    2013-01-01

    Lamins are the major components of nuclear envelope architecture, being required for both the structural and informational roles of the nuclei. Mutations of lamins cause a spectrum of diseases in humans, including muscular dystrophy. We report here that the loss of the A-type lamin gene, lamin C in Drosophila resulted in pupal metamorphic lethality caused by tendon defects, matching the characteristics of human A-type lamin revealed by Emery-Dreifuss muscular dystrophy (EDMD). In tendon cells lacking lamin C activity, overall cell morphology was affected and organization of the spectraplakin family cytoskeletal protein Shortstop which is prominently expressed in tendon cells gradually disintegrated, notably around the nucleus and in a manner correlating well with the degradation of musculature. Furthermore, lamin C null mutants were efficiently rescued by restoring lamin C expression to shortstop-expressing cells, which include tendon cells but exclude skeletal muscle cells. Thus the critical function of A-type lamin C proteins in Drosophila musculature is to maintain proper function and morphology of tendon cells.

  15. Longitudinal Cell Tracking and Simultaneous Monitoring of Tissue Regeneration after Cell Treatment of Natural Tendon Disease by Low-Field Magnetic Resonance Imaging

    PubMed Central

    Berner, Dagmar; Brehm, Walter; Gerlach, Kerstin; Gittel, Claudia; Offhaus, Julia; Paebst, Felicitas; Scharner, Doreen; Burk, Janina

    2016-01-01

    Treatment of tendon disease with multipotent mesenchymal stromal cells (MSC) is a promising option to improve tissue regeneration. To elucidate the mechanisms by which MSC support regeneration, longitudinal tracking of MSC labelled with superparamagnetic iron oxide (SPIO) by magnetic resonance imaging (MRI) could provide important insight. Nine equine patients suffering from tendon disease were treated with SPIO-labelled or nonlabelled allogeneic umbilical cord-derived MSC by local injection. Labelling of MSC was confirmed by microscopy and MRI. All animals were subjected to clinical, ultrasonographical, and low-field MRI examinations before and directly after MSC application as well as 2, 4, and 8 weeks after MSC application. Hypointense artefacts with characteristically low signal intensity were identified at the site of injection of SPIO-MSC in T1- and T2∗-weighted gradient echo MRI sequences. They were visible in all 7 cases treated with SPIO-MSC directly after injection, but not in the control cases treated with nonlabelled MSC. Furthermore, hypointense artefacts remained traceable within the damaged tendon tissue during the whole follow-up period in 5 out of 7 cases. Tendon healing could be monitored at the same time. Clinical and ultrasonographical findings as well as T2-weighted MRI series indicated a gradual improvement of tendon function and structure. PMID:26880932

  16. Longitudinal Cell Tracking and Simultaneous Monitoring of Tissue Regeneration after Cell Treatment of Natural Tendon Disease by Low-Field Magnetic Resonance Imaging.

    PubMed

    Berner, Dagmar; Brehm, Walter; Gerlach, Kerstin; Gittel, Claudia; Offhaus, Julia; Paebst, Felicitas; Scharner, Doreen; Burk, Janina

    2016-01-01

    Treatment of tendon disease with multipotent mesenchymal stromal cells (MSC) is a promising option to improve tissue regeneration. To elucidate the mechanisms by which MSC support regeneration, longitudinal tracking of MSC labelled with superparamagnetic iron oxide (SPIO) by magnetic resonance imaging (MRI) could provide important insight. Nine equine patients suffering from tendon disease were treated with SPIO-labelled or nonlabelled allogeneic umbilical cord-derived MSC by local injection. Labelling of MSC was confirmed by microscopy and MRI. All animals were subjected to clinical, ultrasonographical, and low-field MRI examinations before and directly after MSC application as well as 2, 4, and 8 weeks after MSC application. Hypointense artefacts with characteristically low signal intensity were identified at the site of injection of SPIO-MSC in T1- and T2 (∗) -weighted gradient echo MRI sequences. They were visible in all 7 cases treated with SPIO-MSC directly after injection, but not in the control cases treated with nonlabelled MSC. Furthermore, hypointense artefacts remained traceable within the damaged tendon tissue during the whole follow-up period in 5 out of 7 cases. Tendon healing could be monitored at the same time. Clinical and ultrasonographical findings as well as T2-weighted MRI series indicated a gradual improvement of tendon function and structure.

  17. Exercise following a short immobilization period is detrimental to tendon properties and joint mechanics in a rat rotator cuff injury model.

    PubMed

    Peltz, Cathryn D; Sarver, Joseph J; Dourte, Leann M; Würgler-Hauri, Carola C; Williams, Gerald R; Soslowsky, Louis J

    2010-07-01

    Rotator cuff tears are a common clinical problem that can result in pain and disability. Previous studies in a rat model showed enhanced tendon to bone healing with postoperative immobilization. The objective of this study was to determine the effect of postimmobilization activity level on insertion site properties and joint mechanics in a rat model. Our hypothesis was that exercise following a short period of immobilization will cause detrimental changes in insertion site properties compared to cage activity following the same period of immobilization, but that passive shoulder mechanics will not be affected. We detached and repaired the supraspinatus tendon of 22 Sprague-Dawley rats, and the injured shoulder was immobilized postoperatively for 2 weeks. Following immobilization, rats were prescribed cage activity or exercise for 12 weeks. Passive shoulder mechanics were determined, and following euthanasia, tendon cross-sectional area and mechanical properties were measured. Exercise following immobilization resulted in significant decreases compared to cage activity in range of motion, tendon stiffness, modulus, percent relaxation, and several parameters from both a structurally based elastic model and a quasi-linear viscoelastic model. Therefore, we conclude that after a short period of immobilization, increased activity is detrimental to both tendon mechanical properties and shoulder joint mechanics, presumably due to increased scar production.

  18. Tibialis posterior tendon and deltoid and spring ligament injuries in the elite athlete.

    PubMed

    Ribbans, William John; Garde, Ajit

    2013-06-01

    The tibialis posterior tendon and the spring and deltoid ligament complexes combine to provide dynamic and passive stabilization on the medial side of the ankle and hindfoot. Some of the injuries will involve acute injury to previous healthy structures, but many will develop insidiously. The clinician must be aware of new treatment strategies and the level of accompanying scientific evidence regarding injuries sustained by athletes in these areas, while acknowledging that more traditional management applied to nonathletic patients is still likely to be appropriate in the setting of treatment for elite athletes.

  19. Bioscaffolds and the reconstruction of ligaments and tendons in the foot and ankle.

    PubMed

    Cook, Jeremy J; Cook, Emily A

    2009-10-01

    Biologic scaffolds have become an integral part of surgical soft tissue reconstruction in recent years. The increased use of these materials can be partially attributed to poor long-term outcomes with synthetic products as well as the cost and morbidity associated with allografts and autografts. Bioscaffolds can augment natural healing processes of tendons and ligaments while providing additional structural support. Although these implants lack the mechanical strength of synthetics and other transplants, proper preparation can optimize their load-sharing capacity. This article presents methods that can improve these characteristics of bioscaffolds. Available studies in foot and ankle applications have shown minimal complications in a variety of techniques.

  20. Connective tissue polarity. Optical second-harmonic microscopy, crossed-beam summation, and small-angle scattering in rat-tail tendon.

    PubMed Central

    Freund, I; Deutsch, M; Sprecher, A

    1986-01-01

    Connective tissue polarity has remained an intractable enigma for over two decades. We present new data on optical second harmonic generation in native, wet, rat-tail tendon. Scanning second-harmonic microscopy has revealed, for the first time, the existence of a discrete network of fine, polar, filamentous or columnar, structures, and, also, the presence of strongly polar surface, or near-surface patches. The thickness of these features was probed via crossed-beam optical frequency summation and the polar material is estimated to occupy a few percent of the tendon volume. The three-dimensional spatial distribution of filaments was studied with the aid of small-angle second-harmonic scattering, and the filaments were found to permeate the tendon cross-section in an apparently random fashion. These latter measurements also revealed that essentially all polar filaments had the same directionality. Concomitant studies of the polar collagen fibrils that comprise the bulk of tendon were in full accord with prior electron microscope results that had demonstrated that the directionality of these fibrils varies up/down in a purely random fashion, and thus cannot yield a net macroscopic polarity. Quantitative analysis of the second-harmonic data yields the conclusion that the observed polar structures cannot be simply local regions containing some accidental net excess of similarly oriented fibrils. The analytical expressions used in the analysis of the data obtained for this complex tissue were supported by extensive, realistic computer simulations. The discovery that the polarity of rat-tail tendon, and possibly other forms of connective tissue, resides in discrete structures, some of which are located near the tendon surface, should permit the ready isolation of polar-rich material for further study by a variety of techniques. Images FIGURE 2 PMID:3779007

  1. 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

    2017-03-16

    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.

  2. Structure, physiology, and biochemistry of collagens.

    PubMed

    Mienaltowski, Michael J; Birk, David E

    2014-01-01

    Tendons and ligaments are connective tissues that guide motion, share loads, and transmit forces in a manner that is unique to each as well as the anatomical site and biomechanical stresses to which they are subjected. Collagens are the major molecular components of both tendons and ligaments. The hierarchical structure of tendon and its functional properties are determined by the collagens present, as well as their supramolecular organization. There are 28 different types of collagen that assemble into a variety of supramolecular structures. The assembly of specific supramolecular structures is dependent on the interaction with other matrix molecules as well as the cellular elements. Multiple suprastructural assemblies are integrated to form the functional tendon/ligament. This chapter begins with a discussion of collagen molecules. This is followed by a definition of the supramolecular structures assembled by different collagen types. The general principles involved in the assembly of collagen-containing suprastructures are presented focusing on the regulation of tendon collagen fibrillogenesis. Finally, site-specific differences are discussed. While generalizations can be made, differences exist between different tendons as well as between tendons and ligaments. Compositional differences will impact structure that in turn will determine functional differences. Elucidation of the unique physiology and pathophysiology of different tendons and ligaments will require an appreciation of the role compositional differences have on collagen suprastructural assembly, tissue organization, and function.

  3. Proteomics-based identification of novel proteins in temporal tendons of patients with masticatory muscle tendon--aponeurosis hyperplasia.

    PubMed

    Nakamoto, A; Sato, T; Hirosawa, N; Nakamoto, N; Enoki, Y; Chida, D; Usui, M; Takeda, S; Nagai, T; Sasaki, A; Sakamoto, Y; Yoda, T

    2014-01-01

    Masticatory muscle tendon-aponeurosis hyperplasia (MMTAH) is a new disease associated with limited mouth opening that is often misdiagnosed as a temporomandibular disorder; subsequently, patients are mistakenly treated with irreversible operations. Due to the poor presentation and characterization of symptoms, the underlying pathological conditions remain unclear. We have previously conducted a proteomic analysis of tendons derived from one MMTAH subject and one facial deformity subject using two-dimensional fluorescence difference gel electrophoresis and liquid chromatography coupled with tandem mass spectrometry. However, the results were obtained for only one subject. The aim of the present study was to confirm the expression of specific molecules in tendon tissues from multiple subjects with MMTAH by applying two-dimensional polyacrylamide gel electrophoresis with matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Of the 19 proteins identified in tendons from both MMTAH and facial deformity patients, fibrinogen fragment D and beta-crystallin A4 were up-regulated, whereas myosin light chain 4 was down-regulated in MMTAH. We also found fibrinogen to be expressed robustly in tendon tissues of MMTAH patients. Our data provide the possibility that the distinctive expression of these novel proteins is associated with the pathology of MMTAH.

  4. Effects of Lubricant and Autologous Bone Marrow Stromal Cell Augmentation on Immobilized Flexor Tendon Repairs

    PubMed Central

    Zhao, Chunfeng; Ozasa, Yasuhiro; Shimura, Haruhiko; Reisdorf, Ramona L.; Thoreson, Andrew R.; Jay, Gregory; Moran, Steven L.; An, Kai-Nan; Amadio, Peter C.

    2016-01-01

    The purpose of the study was to test a novel treatment that carbodiimide-derivatized-hyaluronic acid-lubricin (cd-HA-lubricin) combined cell-based therapy in an immobilized flexor tendon repair in a canine model. Seventy-eight flexor tendons from 39 dogs were transected. One tendon was treated with cd-HA-lubricin plus an interpositional graft of 8 × 105 BMSCs and GDF-5. The other tendon was repaired without treatment. After 21 day of immobilization, 19 dogs were sacrificed; the remaining 20 dogs underwent a 21-day rehabilitation protocol before euthanasia. The work of flexion, tendon gliding resistance, and adhesion score in treated tendons were significantly less than the untreated tendons (p < 0.05). The failure strength of the untreated tendons was higher than the treated tendons at 21 and 42 days (p < 0.05). However, there is no significant difference in stiffness between two groups at day 42. Histologic analysis of treated tendons showed a smooth surface and viable transplanted cells 42 days after the repair, whereas untreated tendons showed severe adhesion formation around the repair site. The combination of lubricant and cell treatment resulted in significantly improved digit function, reduced adhesion formation. This novel treatment can address the unmet needs of patients who are unable to commence an early mobilization protocol after flexor tendon repair. PMID:26177854

  5. Magic angle magnetic resonance imaging of diode laser induced and naturally occurring lesions in equine tendons.

    PubMed

    Spriet, Mathieu; Murphy, Brian; Vallance, Stuart A; Vidal, Martin A; Whitcomb, Mary Beth; Wisner, Erik R

    2012-01-01

    Magic angle magnetic resonance (MR) imaging consists of imaging tendons at 55° to the magnetic field. In people, magic angle MR imaging is valuable for detection of chronic tendon lesions and allows calculation of tendon T1 values. Increased T1 values occur in people with chronic tendinopathy. The T1 values of normal equine tendons have been reported but there are no available data for abnormal equine tendons. Twelve limbs were studied. Two limbs had diode laser tendon lesions induced postmortem, four limbs had diode laser tendon lesions induced in vivo and six limbs had naturally occurring tendon lesions. The limbs were imaged at 1.5 T using both conventional MR imaging and magic angle MR imaging. The post-mortem laser induced lesions were identified only with magic angle MR imaging. The in vivo induced lesions and naturally occurring lesions were identified with both techniques but had a different appearance with the two imaging techniques. Magic angle imaging was helpful at identifying lesions that were hypointense on conventional imaging. Increased T1 values were observed in all abnormal tendons and in several tendons with a subjectively normal MR appearance. The increased T1 value may reflect diffuse changes in the biochemical composition of tendons. Magic angle imaging has potential as a useful noninvasive tool to assess the changes of the extracellular tendon matrix using T1 values.

  6. 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

  7. Partial peroneus longus tendon rupture in professional basketball players: a report of 2 cases.

    PubMed

    Cooper, Mitchell E; Selesnick, F Harlan; Murphy, Brian J

    2002-12-01

    Partial tears of the peroneal tendons are rare. Partial longitudinal tears of the peroneus longus tendon are even more rare. We report on 2 professional basketball players who had partial peroneus longus tendon tears beneath the cuboid. A literature review and discussion of treatment is included.

  8. 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.

  9. A 3D lower limb musculoskeletal model for simultaneous estimation of musculo-tendon, joint contact, ligament and bone forces during gait.

    PubMed

    Moissenet, Florent; Chèze, Laurence; Dumas, Raphaël

    2014-01-03

    Musculo-tendon forces and joint reaction forces are typically estimated using a two-step method, computing first the musculo-tendon forces by a static optimization procedure and then deducing the joint reaction forces from the force equilibrium. However, this method does not allow studying the interactions between musculo-tendon forces and joint reaction forces in establishing this equilibrium and the joint reaction forces are usually overestimated. This study introduces a new 3D lower limb musculoskeletal model based on a one-step static optimization procedure allowing simultaneous musculo-tendon, joint contact, ligament and bone forces estimation during gait. It is postulated that this approach, by giving access to the forces transmitted by these musculoskeletal structures at hip, tibiofemoral, patellofemoral and ankle joints, modeled using anatomically consistent kinematic models, should ease the validation of the model using joint contact forces measured with instrumented prostheses. A blinded validation based on four datasets was made under two different minimization conditions (i.e., C1 - only musculo-tendon forces are minimized, and C2 - musculo-tendon, joint contact, ligament and bone forces are minimized while focusing more specifically on tibiofemoral joint contacts). The results show that the model is able to estimate in most cases the correct timing of musculo-tendon forces during normal gait (i.e., the mean coefficient of active/inactive state concordance between estimated musculo-tendon force and measured EMG envelopes was C1: 65.87% and C2: 60.46%). The results also showed that the model is potentially able to well estimate joint contact, ligament and bone forces and more specifically medial (i.e., the mean RMSE between estimated joint contact force and in vivo measurement was C1: 1.14BW and C2: 0.39BW) and lateral (i.e., C1: 0.65BW and C2: 0.28BW) tibiofemoral contact forces during normal gait. However, the results remain highly influenced by the

  10. Torque resolver design for tendon-driven manipulators

    SciTech Connect

    Lee, J.J.; Tsai, Lung-Wen

    1992-08-01

    Given a set of desired joint torques in an n-DOF tendon-driven manipulator with n + 1 control tendons, the determination of tendon forces is an indeterminate problem. Usually, the pseudo-inverse technique is used to solve for such a problem. In this paper, rather than using the pseudo-inverse technique is used to solve for such a problem. In this paper, rather than using the pseudo-inverse technique, an efficient methodology for transforming joint torques (n elements) to motor torques (n + 1 elements) has been developed. This technique called ``torque resolver``, utilizes two circuit-like operators to transform torques between the two different vector spaces. It can be easily programmed on a digital computer or implemented into an analog-circuit system. It is hoped that this technique will make real-time computed-torque control feasible. The technique has been demonstrated through the dynamic simulation of a three-DOF manipulator.

  11. Torque resolver design for tendon-driven manipulators

    SciTech Connect

    Lee, J.J.; Tsai, Lung-Wen.

    1992-01-01

    Given a set of desired joint torques in an n-DOF tendon-driven manipulator with n + 1 control tendons, the determination of tendon forces is an indeterminate problem. Usually, the pseudo-inverse technique is used to solve for such a problem. In this paper, rather than using the pseudo-inverse technique is used to solve for such a problem. In this paper, rather than using the pseudo-inverse technique, an efficient methodology for transforming joint torques (n elements) to motor torques (n + 1 elements) has been developed. This technique called torque resolver'', utilizes two circuit-like operators to transform torques between the two different vector spaces. It can be easily programmed on a digital computer or implemented into an analog-circuit system. It is hoped that this technique will make real-time computed-torque control feasible. The technique has been demonstrated through the dynamic simulation of a three-DOF manipulator.

  12. An Investigation of Tendon Corrosion-Inhibitor Leakage into Concrete

    SciTech Connect

    Costello, J.F.; Naus, D.J.; Oland, C.B.

    1999-07-05

    During inspections performed at US nuclear power plants several years ago, some of the prestressed concrete containment had experienced leakage of the tendon sheathing filler. A study was conducted to indicate the extent of the leakage into the concrete and its potential effects on concrete properties. Concrete core samples were obtained from the Trojan Nuclear Plant. Examination and testing of the core samples indicated that the appearance of tendon sheathing filler on the surface was due to leakage of the filler from the conduits and its subsequent migration to the concrete surface through cracks that were present. Migration of the tendon sheathing filler was confined to the cracks with no perceptible movement into the concrete. Results of compressive strength tests indicated that the concrete quality was consistent in the containment and that the strength had increased relative to the strength at 28 days age.

  13. Recent Scientific Advances Towards the Development of Tendon Healing Strategies

    PubMed Central

    Sayegh, Eli T.; Sandy, John D.; Virk, Mandeep S.; Romeo, Anthony A.; Wysocki, Robert W.; Galante, Jorge O.; Trella, Katie J.; Plaas, Anna; Wang, Vincent M.

    2015-01-01

    There exists a range of surgical and non-surgical approaches to the treatment of both acute and chronic tendon injuries. Despite surgical advances in the management of acute tears and increasing treatment options for tendinopathies, strategies frequently are unsuccessful, due to impaired mechanical properties of the treated tendon and/or a deficiency in progenitor cell activities. Hence, there is an urgent need for effective therapeutic strategies to augment intrinsic and/or surgical repair. Such approaches can benefit both tendinopathies and tendon tears which, due to their severity, appear to be irreversible or irreparable. Biologic therapies include the utilization of scaffolds as well as gene, growth factor, and cell delivery. These treatment modalities aim to provide mechanical durability or augment the biologic healing potential of the repaired tissue. Here, we review the emerging concepts and scientific evidence which provide a rationale for tissue engineering and regeneration strategies as well as discuss the clinical translation of recent innovations. PMID:26753125

  14. No man's land revisited: the primary flexor tendon repair controversy.

    PubMed

    Newmeyer, William L; Manske, Paul R

    2004-01-01

    New surgical procedures, novel concepts, and/or the presentation of very good results with an apparently discredited technique meet varying degrees of resistance among the establishment of any profession. In hand surgery this phenomenon was exemplified in a striking fashion with the presentation of a controversial report entitled, "Primary repair of flexor tendons in no man's land" by Kleinert, Kutz, Ashbell, and Martinez of Louisville, KY, at the 1967 American Society for Surgery of the Hand (ASSH) annual meeting. The discussant, Joseph Boyes, expressed such skepticism that a special ASSH committee was appointed to go to Louisville and review the results to determine if they were as good as claimed. They were, and today primary flexor tendon repair is the procedure of choice for most flexor tendon lacerations.

  15. Prediction of the elastic strain limit of tendons.

    PubMed

    Reyes, A M; Jahr, H; van Schie, H T M; Weinans, H; Zadpoor, A A

    2014-02-01

    The elastic strain limit (ESL) of tendons is the point where maximum elastic modulus is reached, after which micro-damage starts. Study of damage progression in tendons under repetitive (fatigue) loading requires a priori knowledge about ESL. In this study, we propose three different approaches for predicting ESL. First, one single value is assumed to represent the ESL of all tendon specimens. Second, different extrapolation curves are used for extrapolating the initial part of the stress-strain curve. Third, a method based on comparing the shape of the initial part of the stress-strain curve of specimens with a database of stress-strain curves is used. A large number of porcine tendon explants (97) were tested to examine the above-mentioned approaches. The variants of the third approach yielded significantly (p<0.05) smaller error values as compared to the other approaches. The mean absolute percentage error of the best-performing variant of the shape-based comparison was between 8.14±6.44% and 9.96±9.99% depending on the size of the initial part of the stress-strain curves. Interspecies generalizability of the best performing method was also studied by applying it for prediction of the ESL of horse tendons. The ESL of horse tendons was predicted with mean absolute percentage errors ranging between 10.53±7.6% and 19.16±14.31% depending on the size of the initial part of the stress-strain curves and the type of normalization. The results of this study suggest that both ESL and the shape of stress-strain curves may be highly different between different individuals and different anatomical locations.

  16. Exploring the Potential of Starch/Polycaprolactone Aligned Magnetic Responsive Scaffolds for Tendon Regeneration.

    PubMed

    Gonçalves, Ana I; Rodrigues, Márcia T; Carvalho, Pedro P; Bañobre-López, Manuel; Paz, Elvira; Freitas, Paulo; Gomes, Manuela E

    2016-01-21

    The application of magnetic nanoparticles (MNPs) in tissue engineering (TE) approaches opens several new research possibilities in this field, enabling a new generation of multifunctional constructs for tissue regeneration. This study describes the development of sophisticated magnetic polymer scaffolds with aligned structural features aimed at applications in tendon tissue engineering (TTE). Tissue engineering magnetic scaffolds are prepared by incorporating iron oxide MNPs into a 3D structure of aligned SPCL (starch and polycaprolactone) fibers fabricated by rapid prototyping (RP) technology. The 3D architecture, composition, and magnetic properties are characterized. Furthermore, the effect of an externally applied magnetic field is investigated on the tenogenic differentiation of adipose stem cells (ASCs) cultured onto the developed magnetic scaffolds, demonstrating that ASCs undergo tenogenic differentiation synthesizing a Tenascin C and Collagen type I rich matrix under magneto-stimulation conditions. Finally, the developed magnetic scaffolds were implanted in an ectopic rat model, evidencing good biocompatibility and integration within the surrounding tissues. Together, these results suggest that the effect of the magnetic aligned scaffolds structure combined with magnetic stimulation has a significant potential to impact the field of tendon tissue engineering toward the development of more efficient regeneration therapies.

  17. The Role of Bioreactors in Ligament and Tendon Tissue Engineering.

    PubMed

    Mace, James; Wheelton, Andy; Khan, Wasim S; Anand, Sanj

    2016-01-01

    Bioreactors are pivotal to the emerging field of tissue engineering. The formation of neotissue from pluripotent cell lineages potentially offers a source of tissue for clinical use without the significant donor site morbidity associated with many contemporary surgical reconstructive procedures. Modern bioreactor design is becoming increasingly complex to provide a both an expandable source of readily available pluripotent cells and to facilitate their controlled differentiation into a clinically applicable ligament or tendon like neotissue. This review presents the need for such a method, challenges in the processes to engineer neotissue and the current designs and results of modern bioreactors in the pursuit of engineered tendon and ligament.

  18. Variation in the human Achilles tendon moment arm during walking.

    PubMed

    Rasske, Kristen; Thelen, Darryl G; Franz, Jason R

    2017-02-01

    The Achilles tendon (AT) moment arm is an important determinant of ankle moment and power generation during locomotion. Load and depth-dependent variations in the AT moment arm are generally not considered, but may be relevant given the complex triceps surae architecture. We coupled motion analysis and ultrasound imaging to characterize AT moment arms during walking in 10 subjects. Muscle loading during push-off amplified the AT moment arm by 10% relative to heel strike. AT moment arms also varied by 14% over the tendon thickness. In walking, AT moment arms are not strictly dependent on kinematics, but exhibit important load and spatial dependencies.

  19. [Study on the acid hydrolysis, fiber remodeling and bionics mineralization of rat tail tendon collagen type Ⅰ].

    PubMed

    Zhang, Zhan; Zhang, Chun; Guo, Qiaofeng

    2016-05-25

    Objective: To produce bionic bone material that is consistent with human bone in chemical composition and molecular structure using rat tail tendon collagen type Ⅰ. Methods: The type Ⅰcollagen derived from rat tail was extracted by acetic acid to form collagen fibers. The reconstructed collagen fibers were placed in the mineralized solution to mimic bone mineralization for 2-6 days. Bone mineralization was observed by transmission electron microscopy and electron diffraction.Results: Collagen fibers with characteristic D-Band structure were reconstructed by using rat tail tendon collagen type Ⅰ extracted with acid hydrolysis method. Transmission electron microscopy and electron diffraction showed that calcium hydroxyapatite precursor infiltrated into the collagen fibers, and the collagen fibers were partially mineralized after 2 days of mineralization; the collagen fibers were completely mineralized and bionic bone material of typeⅠ collagen/calcium hydroxyapatite was formed after 6 days of mineralization.Conclusion: The collagen type Ⅰ can be extracted from rat tail tendon by acid hydrolysis method, and can be reformed and mineralized to form the bionic bone material which mimics human bone in chemical composition and the molecular structure.

  20. Biomechanical risk factors and flexor tendon frictional work in the cadaveric carpal tunnel.

    PubMed

    Kociolek, Aaron M; Tat, Jimmy; Keir, Peter J

    2015-02-05

    Pathological changes in carpal tunnel syndrome patients include fibrosis and thickening of the subsynovial connective tissue (SSCT) adjacent to the flexor tendons in the carpal tunnel. These clinical findings suggest an etiology of excessive shear-strain force between the tendon and SSCT, underscoring the need to assess tendon gliding characteristics representative of repetitive and forceful work. A mechanical actuator moved the middle finger flexor digitorum superficialis tendon proximally and distally in eight fresh frozen cadaver arms. Eighteen experimental conditions tested the effects of three well-established biomechanical predictors of injury, including a combination of two wrist postures (0° and 30° flexion), three tendon velocities (50, 100, 150mm/sec), and three forces (10, 20, 40N). Tendon gliding resistance was determined with two light-weight load cells, and integrated over tendon displacement to represent tendon frictional work. During proximal tendon displacement, frictional work increased with tendon velocity (58.0% from 50-150mm/sec). There was a significant interaction between wrist posture and tendon force. In wrist flexion, frictional work increased 93.0% between tendon forces of 10 and 40N. In the neutral wrist posture, frictional work only increased 33.5% (from 10-40N). During distal tendon displacement, there was a similar multiplicative interaction on tendon frictional work. Concurrent exposure to multiple biomechanical work factors markedly increased tendon frictional work, thus providing a plausible link to the pathogenesis of work-related carpal tunnel syndrome. Additionally, our study provides the conceptual basis to evaluate injury risk, including the multiplicative repercussions of combined physical exposures.

  1. Both standing and postural threat decrease Achilles tendon reflex inhibition from tendon electrical stimulation.

    PubMed

    Horslen, Brian C; Inglis, J Timothy; Blouin, Jean-Sébastien; Carpenter, Mark G

    2017-03-22

    Golgi tendon organ Ib reflexes are thought to contribute to standing balance control, but it is unknown if they are modulated when people are exposed to a postural threat. We used a novel application of tendon electrical stimulation (TStim) to elicit Ib inhibitory reflexes in the medial gastrocnemius, while actively engaged in upright standing balance, to examine a) how Ib reflexes to TStim are influenced by upright stance, and b) the effects of height-induced postural threat on Ib reflexes during standing. TStim evoked short-latency (<47 ms) inhibition apparent in trigger-averaged rectified EMG, which was quantified in terms of area, duration, and mean amplitude of inhibition. In order to validate the use of TStim in a standing model, TStim-Ib inhibition was compared from conditions where participants were laying prone vs. standing upright. TStim evoked Ib inhibition in both conditions, however significant reductions in Ib inhibition area (42.2%) and duration (32.9%) were observed during stance. Postural threat, manipulated by having participants stand at LOW (0.8 m high, 0.6 m from edge) and HIGH (3.2 m, at edge) elevated surfaces, significantly reduced Ib inhibition area (32.4%), duration (16.4%) and amplitude (24.8%) in the HIGH, compared to LOW threat condition. These results demonstrate TStim is a viable technique for investigating Ib reflexes in standing, and confirm Ib reflexes are modulated with postural orientation. The novel observation of reduced Ib inhibition with elevated postural threat reveals that human Ib reflexes are context-dependent, and the human Ib reflex pathways are modulated by threat or emotional processing centres of the CNS. This article is protected by copyright. All rights reserved.

  2. 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 Central

    2016-01-01

    Background 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. Materials and Methods 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. Results 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. Conclusion 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. PMID:27606597

  3. Acute tear of the fascia cruris at the attachment to the Achilles tendon: a new diagnosis

    PubMed Central

    Webborn, Nick; Morrissey, Dylan; Sarvananthan, Kasthuri; Chan, Otto

    2015-01-01

    Background The fascia cruris encloses the posterior structures of the calf and connects to the paratenon and the Achilles tendon. We describe the clinical presentation, ultrasound imaging characteristics and the time to the recovery of tears of the fascia cruris at the attachment to the Achilles tendon. Methods Retrospective review of 11 tears of the fascia cruris in the different legs as separate events in 9 patients (6 male and 3 female, mean age 35.52 years, range 11–48) identified using diagnostic ultrasound, after presenting with Achillodynia. Results 11 participants presented at a mean of 4.5 weeks (range 0.5–12) after onset of symptoms. The left Achilles was more commonly injured than the right (7 : 4) and the lateral side more than the medial (6 : 4) with one case with medial and lateral presentation. Clinically, there was swelling and tenderness over the medial or lateral border in the mid to upper portion of the Achilles. 7 of the 11 (63.6%) had functional overpronation. Ultrasound appearances of a tear were identified as hypoechoic area extending from the medial or lateral border of the Achilles extending along the anatomical plane of the fascia cruris. Average return to activity was 5.2 weeks (range 1–22). Participants presenting later had longer recovery but all participants returned to full activity (r=0.4). Conclusions This is the first description of the clinical details and sonographic findings of a tear to the fascia cruris at its attachment to the Achilles tendon. This needs to be considered as a cause of Achillodynia in athletes as recognition will affect the management. PMID:25202137

  4. DNA fragmentation and nuclear phenotype in tendons exposed to low-intensity infrared laser

    NASA Astrophysics Data System (ADS)

    de Paoli, Flavia; Ramos Cerqueira, Larissa; Martins Ramos, Mayara; Campos, Vera M.; Ferreira-Machado, Samara C.; Geller, Mauro; de Souza da Fonseca, Adenilson

    2015-03-01

    Clinical protocols are recommended in device guidelines outlined for treating many diseases on empirical basis. However, effects of low-intensity infrared lasers at fluences used in clinical protocols on DNA are controversial. Excitation of endogenous chromophores in tissues and free radicals generation could be described as a consequence of laser used. DNA lesions induced by free radicals cause changes in DNA structure, chromatin organization, ploidy degrees and cell death. In this work, we investigated whether low-intensity infrared laser therapy could alter the fibroblasts nuclei characteristics and induce DNA fragmentation. Tendons of Wistar rats were exposed to low-intensity infrared laser (830 nm), at different fluences (1, 5 and 10 J/cm2), in continuous wave (power output of 10mW, power density of 79.6 mW/cm2). Different frequencies were analyzed for the higher fluence (10 J/cm2), at pulsed emission mode (2.5, 250 and 2500 Hz), with the laser source at surface of skin. Geometric, densitometric and textural parameters obtained for Feulgen-stained nuclei by image analysis were used to define nuclear phenotypes. Significant differences were observed on the nuclear phenotype of tendons after exposure to laser, as well as, high cell death percentages was observed for all fluences and frequencies analyzed here, exception 1 J/cm2 fluence. Our results indicate that low-intensity infrared laser can alter geometric, densitometric and textural parameters in tendon fibroblasts nuclei. Laser can also induce DNA fragmentation, chromatin lost and consequently cell death, using fluences, frequencies and emission modes took out from clinical protocols.

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

    PubMed Central

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

    2012-01-01

    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). PMID:23396264

  6. Growth factor and protease expression during different phases of healing after rabbit deep flexor tendon repair.

    PubMed

    Berglund, M E; Hart, D A; Reno, C; Wiig, M

    2011-06-01

    The purpose of the study was to contribute to the mapping of molecular events during flexor tendon healing, in particular the growth factors insulin-like growth factor-1 (IGF-1), vascular endothelial growth factor (VEGF) and nerve growth factor (NGF), matrix metalloproteinases (MMP-3 and MMP-13) and their inhibitors (tissue inhibitors of metalloproteinases, TIMP-1 and TIMP-3, and the protease cathepsin K. In a rabbit model of flexor tendon injury, the mRNA expression for the growth factors, MMPs and TIMPs were measured in tendon and tendon sheath tissue at several time points (3, 6, 21, and 42 days) representing different phases of the healing process. We found that MMP-13 remained increased during the study period, whereas MMP-3 returned to normal levels within the first week after injury. TIMP-3 was down-regulated in the tendon sheaths. Cathepsin K was up-regulated in tendons and sheaths after injury. NGF was present in both tendons and sheaths, but unaltered. IGF-1 exhibited a late increase in the tendons, while VEGF was down-regulated at the later time points. In conclusion, we have demonstrated the presence of NGF in flexor tendons. MMP-13 expression appears to play a more protracted role in flexor tendon healing than MMP-3. The relatively low levels of endogenous IGF-1 and VEGF mRNA following injury support their potential beneficial role as exogenous modulators to optimize tendon healing and strength without increasing adhesion formation.

  7. Ultrasound characteristics of the patellar and quadriceps tendons among young elite athletes.

    PubMed

    Visnes, H; Tegnander, A; Bahr, R

    2015-04-01

    Tendons adapt in response to sports-specific loading, but sometimes develop tendinopathy. If the presence of ultrasound changes like hypoechoic areas and neovascularization in asymptomatic tendons precede (and predict) future tendon problems is unknown. The aim of this prospective cohort study was to investigate the relationship between the development of ultrasound changes in the patellar and quadriceps tendons and symptoms of jumper's knee, as well to examine the medium-term effects of intensive training on tendon thickness among adolescent athletes. Elite junior volleyball athletes were followed with semi-annual ultrasound and clinical examinations (average follow-up: 1.7 years). Of the 141 asymptomatic athletes included, 22 athletes (35 patellar tendons) developed jumper's knee. In a multivariate logistic regression analysis, a baseline finding of a hypoechoic tendon area (odds ratio 3.3, 95% confidence interval 1.1 to 9.2) increased the risk of developing symptoms of jumper's knee. Patellar tendon thickness among healthy athletes did not change (Wilk's lambda, P = 0.07) while quadriceps tendon thickness increased (P = 0.001). In conclusion, ultrasound changes a