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Sample records for tendons structural

  1. 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. PMID:25922092

  2. 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

  3. Structural properties of the subscapularis tendon.

    PubMed

    Halder, A; Zobitz, M E; Schultz, E; An, K N

    2000-09-01

    The subscapularis muscle is an important mover and stabilizer of the glenohumeral joint. The purpose of this study was to measure regional variations in the structural properties of the subscapularis tendon in two joint positions. Subscapularis tendons from cadaveric shoulders were divided into four sections superiorly to inferiorly and tested to failure at 0 or 60 degrees of glenohumeral abduction. Arm position had a significant influence on stiffness in the inferior and superior portions (p < 0.05). The inferior region showed a higher stiffness in the hanging-arm position (0 degrees) than at 60 degrees of abduction (27.4+/-17.7 compared with 9.5+/-5.9 N/mm). Meanwhile, stiffness of the superior portion was higher at 60 degrees of abduction than in the hanging-arm position (208.7+/-60.9 compared with 147.2+/-32.3 N/mm). In the hanging-arm position (0 degrees) and at 60 degrees of abduction, the superior and midsuperior portions failed at significantly higher loads (superior: 623.2+/-198.6 and 478.2+/-206.6 N at 0 and 60 degrees of abduction, respectively; midsuperior: 706.2+/-164.6 and 598.4+/-268.4 N, respectively) than did the inferior portion (75.1+/-54.2 and 30.3+/-13.0 N, respectively). Likewise, stiffness of the superior and midsuperior portions was significantly higher than that of the inferior region in both positions. Higher stiffness and ultimate load in the superior tendon region may explain the infrequent extension of rotator cuff tears into the subscapularis tendon. Conversely, the significantly lower ultimate load and stiffness in the inferior tendon region could facilitate anterior dislocation of the humeral head when this portion stabilizes the joint in a dislocated position. Therefore, repair of torn inferior portions of the subscapularis tendon should be considered in surgery for glenohumeral instability. PMID:11117307

  4. Structure-function relationships in tendons: a review.

    PubMed

    Benjamin, M; Kaiser, E; Milz, S

    2008-03-01

    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. 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

  6. PAPP-A affects tendon structure and mechanical properties.

    PubMed

    Yang, Tai-Hua; Thoreson, Andrew R; An, Kai-Nan; Zhao, Chunfeng; Conover, Cheryl A; Amadio, Peter C

    2015-10-01

    Pregnancy-associated plasma protein-A (PAPP-A) serves to increase local insulin-like growth factor (IGF) stimulation of proliferation and differentiation in many tissues through proteolysis of inhibitory IGF-binding proteins. The purpose of this study was to investigate the effects of PAPP-A on tendon structure and mechanical properties. A total of 30 tails from 6-month-old mice were tested with 10 tails in each of following groups: PAPP-A knockout (KO), skeletal-specific PAPP-A overexpressing transgenic (Tg) and wild type (WT). Morphologically, the total tail cross-sectional area (CSA), individual tissue CSAs of bone, muscle and tendon, and fascicle diameter were measured. A fascicle pullout test was performed to assess stiffness and strength of interfascicular structures. Fascicles were mechanically characterized through low and high displacement rate uniaxial tension tests providing modulus at each rate, hysteresis area and stress relaxation ratio. The KO mice had a smaller total tail CSA (p<0.05), fascicle diameter (p<0.05), absolute tendon CSA (p<0.05), fast and slow stiffness (p<0.05 for both) and larger hysteresis area (p<0.05) compared to WT and Tg mice. On the other hand, the Tg mice had a larger fascicle diameter (p<0.05), absolute tendon CSA (p<0.05), higher interfascicular strength and stiffness (p<0.05) and lower fascicular modulus at low displacement rates (p<0.05) compared to WT and KO mice. Tg mice also had larger total tail CSA area (p<0.05) and smaller hysteresis area (p<0.05) than KO mice, and larger normalized tendon CSA (p<0.05) than WT mice. Based on these data, we conclude that PAPP-A affects fascicle structure, thereby affecting tendon phenotype. PMID:26306763

  7. Biomechanical and structural response of healing Achilles tendon to fatigue loading following acute injury

    PubMed Central

    Freedman, Benjamin R.; Sarver, Joseph J.; Buckley, Mark R.; Voleti, Pramod B.; Soslowsky, Louis J.

    2013-01-01

    Achilles tendon injuries affect both athletes and the general population, and their incidence is rising. In particular, the Achilles tendon is subject to dynamic loading at or near failure loads during activity, and fatigue induced damage is likely a contributing factor to ultimate tendon failure. Unfortunately, little is known about how injured Achilles tendons respond mechanically and structurally to fatigue loading during healing. Knowledge of these properties remains critical to best evaluate tendon damage induction and the ability of the tendon to maintain mechanical properties with repeated loading. Thus, this study investigated the mechanical and structural changes in healing mouse Achilles tendons during fatigue loading. Twenty four mice received bilateral full thickness, partial width excisional injuries to their Achilles tendons (IACUC approved) and twelve tendons from six mice were used as controls. Tendons were fatigue loaded to assess mechanical and structural properties simultaneously after 0, 1, 3, and 6 weeks of healing using an integrated polarized light system. Results showed that the number of cycles to failure decreased dramatically (37-fold, p<0.005) due to injury, but increased throughout healing, ultimately recovering after 6 weeks. The tangent stiffness, hysteresis, and dynamic modulus did not improve with healing (p<0.005). Linear regression analysis was used to determine relationships between mechanical and structural properties. Of tendon structural properties, the apparent birefringence was able to best predict dynamic modulus (R2=0.88–0.92) throughout healing and fatigue life. This study reinforces the concept that fatigue loading is a sensitive metric to assess tendon healing and demonstrates potential structural metrics to predict mechanical properties. PMID:24280564

  8. Immediate and short-term effects of exercise on tendon structure: biochemical, biomechanical and imaging responses.

    PubMed

    Tardioli, Alex; Malliaras, Peter; Maffulli, Nicola

    2012-09-01

    Introduction Tendons are metabolically active structures, and their biochemical, biomechanical and structural properties adapt to chronic exercise. However, abnormal adaptations may lead to the development of tendinopathy and pain. Acute and subacute adaptations might contribute to tendon pathology. Sources of data A systematic search of peer-reviewed articles was performed using a wide range of electronic databases. A total of 61 publications were selected. Areas of agreement Exercise induces acute responses in collagen turnover, blood flow, glucose, lactate and other inflammatory products (e.g. prostaglandins and interleukins). Mechanical properties are influenced by activity duration and intensity. Acute bouts of exercise affect tendon structure, with some of the changes resembling those reported in pathological tendons. Areas of controversy Given the variation in study designs, measured parameters and outcomes, it remains debatable how acute exercise influences overall tendon properties. There is discrepancy regarding which investigation modality and settings provide optimal assessment of each parameter. Growing points There is a need for greater homogeneity between study designs, including subject consortium and age, exercise protocols and time frames for parameter assessing. Areas timely for developing research Innovative methods, measuring each parameter simultaneously, would allow a greater understanding of how and when changes occur. This methodology is key to revealing pathological processes and pathways that alter tendon properties according to various activities. Optimal tendon properties differ between activities: more compliant tendons are beneficial for slow stretch shortening cycle (SSC) activities such as countermovement jumps, whereas stiffer tendons are considered beneficial for fast SSC movements such as sprinting. PMID:22279080

  9. 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. PMID:25808209

  10. The twisted structure of the human Achilles tendon.

    PubMed

    Edama, M; Kubo, M; Onishi, H; Takabayashi, T; Inai, T; Yokoyama, E; Hiroshi, W; Satoshi, N; Kageyama, I

    2015-10-01

    The Achilles tendon (AT) consists of fascicles that originate from the medial head of the gastrocnemius (MG), lateral head of the gastrocnemius (LG), and soleus muscle (Sol). These fascicles are reported to have a twisted structure. However, there is no consensus as to the degree of torsion. The purpose of this study was to investigate the twisted structure of the AT at the level of fascicles that originate from the MG, LG, and Sol, and elucidate the morphological characteristics. Gross anatomical study of 60 Japanese cadavers (111 legs) was used. The AT fascicles originated from the MG, LG, and Sol were fused while twisting among themselves. There were three classification types depending on the degree of torsion. Further fine separation of each fascicle revealed MG ran fairly parallel in all types, whereas LG and Sol, particularly of the extreme type, were inserted onto the calcaneal tuberosity with strong torsion. In addition, the sites of Sol torsion were 3-5?cm proximal to the calcaneal insertion of the AT. These findings provide promising basic data to elucidate the functional role of the twisted structure and mechanisms for the occurrence of AT injury and other conditions. PMID:25557958

  11. Coordinated Development of Muscles and Tendon-Like Structures: Early Interactions in the Drosophila Leg

    PubMed Central

    Soler, Cedric; Laddada, Lilia; Jagla, Krzysztof

    2016-01-01

    The formation of the musculoskeletal system is a remarkable example of tissue assembly. In both vertebrates and invertebrates, precise connectivity between muscles and skeleton (or exoskeleton) via tendons or equivalent structures is fundamental for movement and stability of the body. The molecular and cellular processes underpinning muscle formation are well-established and significant advances have been made in understanding tendon development. However, the mechanisms contributing to proper connection between these two tissues have received less attention. Observations of coordinated development of tendons and muscles suggest these tissues may interact during the different steps in their development. There is growing evidence that, depending on animal model and muscle type, these interactions can take place from progenitor induction to the final step of the formation of the musculoskeletal system. Here, we briefly review and compare the mechanisms behind muscle and tendon interaction throughout the development of vertebrates and Drosophila before going on to discuss our recent findings on the coordinated development of muscles and tendon-like structures in Drosophila leg. By altering apodeme formation (the functional Drosophila equivalent of tendons in vertebrates) during the early steps of leg development, we affect the spatial localization of subsequent myoblasts. These findings provide the first evidence of the developmental impact of early interactions between muscle and tendon-like precursors, and confirm the appendicular Drosophila muscle system as a valuable model for studying these processes. PMID:26869938

  12. Coordinated Development of Muscles and Tendon-Like Structures: Early Interactions in the Drosophila Leg.

    PubMed

    Soler, Cedric; Laddada, Lilia; Jagla, Krzysztof

    2016-01-01

    The formation of the musculoskeletal system is a remarkable example of tissue assembly. In both vertebrates and invertebrates, precise connectivity between muscles and skeleton (or exoskeleton) via tendons or equivalent structures is fundamental for movement and stability of the body. The molecular and cellular processes underpinning muscle formation are well-established and significant advances have been made in understanding tendon development. However, the mechanisms contributing to proper connection between these two tissues have received less attention. Observations of coordinated development of tendons and muscles suggest these tissues may interact during the different steps in their development. There is growing evidence that, depending on animal model and muscle type, these interactions can take place from progenitor induction to the final step of the formation of the musculoskeletal system. Here, we briefly review and compare the mechanisms behind muscle and tendon interaction throughout the development of vertebrates and Drosophila before going on to discuss our recent findings on the coordinated development of muscles and tendon-like structures in Drosophila leg. By altering apodeme formation (the functional Drosophila equivalent of tendons in vertebrates) during the early steps of leg development, we affect the spatial localization of subsequent myoblasts. These findings provide the first evidence of the developmental impact of early interactions between muscle and tendon-like precursors, and confirm the appendicular Drosophila muscle system as a valuable model for studying these processes. PMID:26869938

  13. Tendon structure and extracellular matrix components are affected by spasticity in cerebral palsy patients

    PubMed Central

    Gagliano, Nicoletta; Menon, Alessandra; Martinelli, Carla; Pettinari, Letizia; Panou, Artemisia; Milzani, Aldo; Dalle-Donne, Isabella; Portinaro, Nicola Marcello

    2013-01-01

    Summary We studied the effect of spasticity-induced overload on tendons from the gracilis and semitendinosus muscles from cerebral palsy (CP) and healthy subjects (CT) stained with haematoxylineosin, Sirius red and Alcian blue. Vascularity was also characterized using an anti-CD34 antibody. Light microscopy analysis of haematoxylin-eosin stained sections revealed that the overall structure of tendons was maintained, characterized by parallel and slightly wavy collagen fibers in both CT and CP tendons. However, hypercellularity, cell rounding, increased vascularity and lipoid degeneration were observed in CP samples. Sirius red stained collagen fibers were more evident in CP tendons, suggesting an increased collagen content induced by spasticity. Alcian blue staining revealed an overall increase of glycosaminoglycans in CP tendons as observed in tendinopathy. Our results suggest that CP-induced spasticity may be considered as a chronic, persisting and repetitive loading of tendons, inducing ECM remodeling as adaptive response to increased functional demand. At the same time, the evidence of some tendinopathic-like markers in CP tendons suggests that the chronic nature of the CP condition could represent a pathologic condition, possibly leading to a transient weakness of the tissue making it more susceptible to damage from cumulative loading until an overt tendinopathy develops. PMID:23885344

  14. Molecular structure of tail tendon fibers in TIEG1 knockout mice using synchrotron diffraction technology

    PubMed Central

    Gumez, Laurie; Doucet, Jean; Haddad, Oualid; Hawse, John R.; Subramaniam, Malayannan; Spelsberg, Thomas C.; Pichon, Chantal

    2010-01-01

    The purpose of this study was to characterize the effect of TIEG1 on the molecular structure of collagen within tail tendon fibers using 3-mo-old female C57BL/6 wild-type (WT) and TIEG1 KO mice. Synchrotron X-ray microdiffraction experiments were carried out on single tendon fibers extracted from the WT and TIEG1 KO dorsal tail tendon. The fibers were scanned in the radial direction, and X-ray patterns were obtained. From these patterns, the meridional direction was analyzed through X-ray intensity profile. In addition, collagen content was investigated using hydroxyproline assays, and qualitative real-time PCR experiments were performed on RNA isolated from fibroblasts to examine specific gene expression changes. The results showed different X-ray diffraction patterns between WT and TIEG1 KO tendon fibers, indicating a disorganization of the collagen structure for the TIEG1 KO compared with WT mice. Furthermore, the analyses of the X-ray intensity profiles exhibited a higher (23 ?) period of collagen for the TIEG1 KO compared with the WT mice. The results of the hydroxyproline assays revealed a significant decrease in the TIEG1 KO compared with WT mice, leading to a decrease in the total amount of collagen present within the TIEG1 KO tendons. Moreover, qualitative real-time PCR results showed differences in the expression profiles of specific genes known to play important roles in tendon fiber development. These data further elucidate the role of TIEG1 on tendon structure and could explain the previous defects in the structure-function relationship found for TIEG1 KO tendon fibers. PMID:20378701

  15. Tendon structure changes after maximal exercise in the Thoroughbred horse: use of ultrasound tissue characterisation to detect in vivo tendon response.

    PubMed

    Docking, S I; Daffy, J; van Schie, H T M; Cook, J L

    2012-12-01

    Investigations into the response of the superficial digital flexor tendon (SDFT) of the Thoroughbred horse to mechanical stimuli have been limited to in vitro cell culture studies focused primarily on gene expression of critical matrix proteins. It is uncertain how well in vitro outcomes translate to the tendon of the horse during exercise. The current study examined changes in tendon structure in response to maximal exercise using ultrasound tissue characterisation (UTC) to scan the SDFT prior to and after competitive racing. UTC uses contiguous transverse ultrasound images to assess the dynamics of the echopattern, which has a close relationship with changes in the 3-D ultra-structure of the tendon. Using UTC, it was possible to detect subtle changes in the dynamics of the echopattern, with a reduction in pixels that represent aligned and integer collagen tendon bundles on days 1 and 2 post-race when compared to pre-race (P<0.05). The echopattern of these tendons returned to baseline on day 3. This change in echopattern was not seen in control horses. It was concluded that short-term changes in the SDFT following maximal exercise could be detected using UTC. PMID:22658820

  16. Muscle–tendon structure and dimensions in adults and children

    PubMed Central

    O’Brien, Thomas D; Reeves, Neil D; Baltzopoulos, Vasilios; Jones, David A; Maganaris, Constantinos N

    2010-01-01

    Muscle performance is closely related to the architecture and dimensions of the muscle–tendon unit and the effect of maturation on these architectural characteristics in humans is currently unknown. This study determined whether there are differences in musculo-tendinous architecture between adults and children of both sexes. Fascicle length and pennation angle were measured from ultrasound images at three sites along the length of the vastus intermedius, vastus lateralis, vastis medialis and rectus femoris muscles. Muscle volume and muscle–tendon length were measured from magnetic resonance images. Muscle physiological cross-sectional area (PCSA) was calculated as the ratio of muscle volume to optimum fascicle length. Fascicle length was greater in the adult groups than in children (P < 0.05) but pennation angle did not differ between groups (P > 0.05). The ratios between fascicle and muscle length and between fascicle and tendon length were not different (P > 0.05) between adults and children for any quadriceps muscle. Quadriceps volume and PCSA of each muscle were greater in adults than children (P < 0.01) but the relative proportion of each head to the total quadriceps volume was similar in all groups. However, the difference in PCSA between adults and children (men ? 104% greater than boys, women ? 57% greater than girls) was greater (P < 0.05) than the difference in fascicle length (men ? 37% greater than boys, women ? 10% greater than girls). It is concluded that the fascicle, muscle and tendon lengthen proportionally during maturation, thus the muscle–tendon stiffness and excursion range are likely to be similar in children and adults but the relatively greater increase in PCSA than fascicle length indicates that adult muscles are better designed for force production than children’s muscles. PMID:20345856

  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 (n?) arising under a fundamental guided-wave excitation at (?). Experimental results will be presented to identify (a) ranges of fundamental excitations at (?) 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. Helical sub-structures in energy-storing tendons provide a possible mechanism for efficient energy storage and return.

    PubMed

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

    2013-08-01

    The predominant function of tendons is to position the limb during locomotion. Specific tendons also act as energy stores. Energy-storing (ES) tendons are prone to injury, the incidence of which increases with age. This is likely related to their function; ES tendons are exposed to higher strains and require a greater ability to recoil than positional tendons. The specialized properties of ES tendons are thought to be achieved through structural and compositional differences. However, little is known about structure-function relationships in tendons. This study uses fascicles from the equine superficial digital flexor (SDFT) and common digital extensor (CDET) as examples of ES and positional tendons. We hypothesized that extension and recoil behaviour at the micro-level would differ between tendon types, and would alter with age in the injury-prone SDFT. Supporting this, the results show that extension in the CDET is dominated by fibre sliding. By contrast, greater rotation was observed in the SDFT, suggesting a helical component to fascicles in this tendon. This was accompanied by greater recovery and less hysteresis loss in SDFT samples. In samples from aged SDFTs, the amount of rotation and the ability to recover decreased, while hysteresis loss increased. These findings indicate that fascicles in the ES SDFT may have a helical structure, enabling the more efficient recoil observed. Further, the helix structure appears to alter with ageing; this coincides with a reduction in the ability of SDFT fascicles to recoil. This may affect tendon fatigue resistance and predispose aged tendons to injury. PMID:23669621

  19. 77 FR 69508 - Inservice Inspection of Prestressed Concrete Containment Structures With Grouted Tendons

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-19

    ...The U.S. Nuclear Regulatory Commission (NRC) is issuing a revision to Regulatory Guide (RG) 1.90, ``Inservice Inspection of Prestressed 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 concrete containment structures with grouted...

  20. 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. PMID:23623311

  1. 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 (n?) arising under a fundamental guided-wave excitation at (?). 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.

  2. The 3D structure of crimps in the rat Achilles tendon.

    PubMed

    Raspanti, Mario; Manelli, Alessandro; Franchi, Marco; Ruggeri, Alessandro

    2005-10-01

    The ultrastructure of crimps of the Achilles tendon of rat, excised and processed in a slack condition, was investigated by atomic force microscopy in air, in fluid and by scanning electron microscopy and stereo reconstruction. The tendon was made of distinct fascicles, each comprising a succession of straight segments connected by sharp angles. The length of the segments and the interposed angles varied widely. In particular, the angles ranged from almost zero to over 135 degrees . We did not observe a unique structure for the hinge regions, but rather a variety of gradations of buckling and/or torsion with no evident correlation with other features of tendon. A constant hallmark was the local loss of regular molecular packing, as revealed by the disappearance of the D-banding. Our results do not support recent reports of a helical structure or smooth sinusoidal waves in tendons. Such structures may nonetheless exist in other non-tensile structures whose collagen fibrils exhibit a helical inner architecture and are able to follow a highly convoluted course without buckling or crimping. PMID:16125376

  3. 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.

  4. 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 ...

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

    NASA Astrophysics Data System (ADS)

    Nigdeli, Sinan Melih; Boduro?lu, 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.

  6. Effect of tear size, corticosteroids and subacromial decompression surgery on the hierarchical structural properties of torn supraspinatus tendons

    PubMed Central

    Tilley, J. M. R.; Murphy, R. J.; Chaudhury, S.; Czernuszka, J. T.; Carr, A. J.

    2014-01-01

    Objectives The effects of disease progression and common tendinopathy treatments on the tissue characteristics of human rotator cuff tendons have not previously been evaluated in detail owing to a lack of suitable sampling techniques. This study evaluated the structural characteristics of torn human supraspinatus tendons across the full disease spectrum, and the short-term effects of subacromial corticosteroid injections (SCIs) and subacromial decompression (SAD) surgery on these structural characteristics. Methods Samples were collected inter-operatively from supraspinatus tendons containing small, medium, large and massive full thickness tears (n = 33). Using a novel minimally invasive biopsy technique, paired samples were also collected from supraspinatus tendons containing partial thickness tears either before and seven weeks after subacromial SCI (n = 11), or before and seven weeks after SAD surgery (n = 14). Macroscopically normal subscapularis tendons of older patients (n = 5, mean age = 74.6 years) and supraspinatus tendons of younger patients (n = 16, mean age = 23.3) served as controls. Ultra- and micro-structural characteristics were assessed using atomic force microscopy and polarised light microscopy respectively. Results Significant structural differences existed between torn and control groups. Differences were identifiable early in the disease spectrum, and increased with increasing tear size. Neither SCI nor SAD surgery altered the structural properties of partially torn tendons seven weeks after treatment. Conclusions These findings may suggest the need for early clinical intervention strategies for torn rotator cuff tendons in order to prevent further degeneration of the tissue as tear size increases. Further work is required to establish the long-term abilities of SCI and SAD to prevent, and even reverse, such degeneration. Cite this article: Bone Joint Res 2014;3:252–61. PMID:25106417

  7. ``Aligned-to-random'' nanofiber scaffolds for mimicking the structure of the tendon-to-bone insertion site

    NASA Astrophysics Data System (ADS)

    Xie, Jingwei; Li, Xiaoran; Lipner, Justin; Manning, Cionne N.; Schwartz, Annie G.; Thomopoulos, Stavros; Xia, Younan

    2010-06-01

    We have demonstrated the fabrication of ``aligned-to-random'' electrospun nanofiber scaffolds that mimic the structural organization of collagen fibers at the tendon-to-bone insertion site. Tendon fibroblasts cultured on such a scaffold exhibited highly organized and haphazardly oriented morphologies, respectively, on the aligned and random portions.We have demonstrated the fabrication of ``aligned-to-random'' electrospun nanofiber scaffolds that mimic the structural organization of collagen fibers at the tendon-to-bone insertion site. Tendon fibroblasts cultured on such a scaffold exhibited highly organized and haphazardly oriented morphologies, respectively, on the aligned and random portions. Electronic supplementary information (ESI) available: Description of materials and methods, fluorescence microscopy images of cell morphology, quantitative analysis of cell morphology and SEM image of pre-mineralized scaffold. See DOI: 10.1039/c0nr00192a

  8. Structure, ontogeny and evolution of the patellar tendon in emus (Dromaius novaehollandiae) and other palaeognath birds

    PubMed Central

    Pitsillides, Andrew A.; Hutchinson, John R.

    2014-01-01

    The patella (kneecap) exhibits multiple evolutionary origins in birds, mammals, and lizards, and is thought to increase the mechanical advantage of the knee extensor muscles. Despite appreciable interest in the specialized anatomy and locomotion of palaeognathous birds (ratites and relatives), the structure, ontogeny and evolution of the patella in these species remains poorly characterized. Within Palaeognathae, the patella has been reported to be either present, absent, or fused with other bones, but it is unclear how much of this variation is real, erroneous or ontogenetic. Clarification of the patella’s form in palaeognaths would provide insight into the early evolution of the patella in birds, in addition to the specialized locomotion of these species. Findings would also provide new character data of use in resolving the controversial evolutionary relationships of palaeognaths. In this study, we examined the gross and histological anatomy of the emu patellar tendon across several age groups from five weeks to 18 months. We combined these results with our observations and those of others regarding the patella in palaeognaths and their outgroups (both extant and extinct), to reconstruct the evolution of the patella in birds. We found no evidence of an ossified patella in emus, but noted its tendon to have a highly unusual morphology comprising large volumes of adipose tissue contained within a collagenous meshwork. The emu patellar tendon also included increasing amounts of a cartilage-like tissue throughout ontogeny. We speculate that the unusual morphology of the patellar tendon in emus results from assimilation of a peri-articular fat pad, and metaplastic formation of cartilage, both potentially as adaptations to increasing tendon load. We corroborate previous observations of a ‘double patella’ in ostriches, but in contrast to some assertions, we find independent (i.e., unfused) ossified patellae in kiwis and tinamous. Our reconstructions suggest a single evolutionary origin of the patella in birds and that the ancestral patella is likely to have been a composite structure comprising a small ossified portion, lost by some species (e.g., emus, moa) but expanded in others (e.g., ostriches). PMID:25551026

  9. Structure, ontogeny and evolution of the patellar tendon in emus (Dromaius novaehollandiae) and other palaeognath birds.

    PubMed

    Regnault, Sophie; Pitsillides, Andrew A; Hutchinson, John R

    2014-01-01

    The patella (kneecap) exhibits multiple evolutionary origins in birds, mammals, and lizards, and is thought to increase the mechanical advantage of the knee extensor muscles. Despite appreciable interest in the specialized anatomy and locomotion of palaeognathous birds (ratites and relatives), the structure, ontogeny and evolution of the patella in these species remains poorly characterized. Within Palaeognathae, the patella has been reported to be either present, absent, or fused with other bones, but it is unclear how much of this variation is real, erroneous or ontogenetic. Clarification of the patella's form in palaeognaths would provide insight into the early evolution of the patella in birds, in addition to the specialized locomotion of these species. Findings would also provide new character data of use in resolving the controversial evolutionary relationships of palaeognaths. In this study, we examined the gross and histological anatomy of the emu patellar tendon across several age groups from five weeks to 18 months. We combined these results with our observations and those of others regarding the patella in palaeognaths and their outgroups (both extant and extinct), to reconstruct the evolution of the patella in birds. We found no evidence of an ossified patella in emus, but noted its tendon to have a highly unusual morphology comprising large volumes of adipose tissue contained within a collagenous meshwork. The emu patellar tendon also included increasing amounts of a cartilage-like tissue throughout ontogeny. We speculate that the unusual morphology of the patellar tendon in emus results from assimilation of a peri-articular fat pad, and metaplastic formation of cartilage, both potentially as adaptations to increasing tendon load. We corroborate previous observations of a 'double patella' in ostriches, but in contrast to some assertions, we find independent (i.e., unfused) ossified patellae in kiwis and tinamous. Our reconstructions suggest a single evolutionary origin of the patella in birds and that the ancestral patella is likely to have been a composite structure comprising a small ossified portion, lost by some species (e.g., emus, moa) but expanded in others (e.g., ostriches). PMID:25551026

  10. 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

  11. A 3D bioprinted complex structure for engineering the muscle-tendon unit.

    PubMed

    Merceron, Tyler K; Burt, Morgan; Seol, Young-Joon; Kang, Hyun-Wook; Lee, Sang Jin; Yoo, James J; Atala, Anthony

    2015-09-01

    Three-dimensional integrated organ printing (IOP) technology seeks to fabricate tissue constructs that can mimic the structural and functional properties of native tissues. This technology is particularly useful for complex tissues such as those in the musculoskeletal system, which possess regional differences in cell types and mechanical properties. Here, we present the use of our IOP system for the processing and deposition of four different components for the fabrication of a single integrated muscle-tendon unit (MTU) construct. Thermoplastic polyurethane (PU) was co-printed with C2C12 cell-laden hydrogel-based bioink for elasticity and muscle development on one side, while poly(ϵ-caprolactone) (PCL) was co-printed with NIH/3T3 cell-laden hydrogel-based bioink for stiffness and tendon development on the other. The final construct was elastic on the PU-C2C12 muscle side (E = 0.39 ± 0.05 MPa), stiff on the PCL-NIH/3T3 tendon side (E = 46.67 ± 2.67 MPa) and intermediate in the interface region (E = 1.03 ± 0.14 MPa). These constructs exhibited >80% cell viability at 1 and 7 d after printing, as well as initial tissue development and differentiation. This study demonstrates the versatility of the IOP system to create integrated tissue constructs with region-specific biological and mechanical characteristics for MTU engineering. PMID:26081669

  12. Using NiTi SMA tendons for vibration control of coastal structures

    NASA Astrophysics Data System (ADS)

    Saadat, S.; Noori, M.; Davoodi, H.; Hou, Z.; Suzuki, Y.; Masuda, A.

    2001-08-01

    Hurricane damage inflicted upon coastal structures, particularly residential structures, results in millions of dollars in financial damage and loss of life each year. A major cause of this damage usually begins with roof uplifts of coastal structures; prevention of roof uplift helps mitigate damage to coastal structures by hurricanes. Development of more effective fastening mechanisms for the connections between the walls and the roofs of these structures will aid in damage reduction to coastal structures. Recent developments in the new field of auto-adaptive materials offer promising opportunities for developing radically new fastening mechanisms. One of the classes of materials in this category is shape memory alloys (SMAs). SMAs are very attractive for structural application because of their major constitutive behaviors such as pseudoelastic characteristics. The pseudoelastic behavior of NiTi SMAs is a unique hysteretic energy dissipation behavior which, combined with a very long fatigue life, makes NiTi a viable candidate for developing new fasteners. However, as a first step it is important to develop an in-depth understanding of NiTi behavior under dynamic loads. Research carried out in this area has been very limited in scope. Therefore, in this paper, eight different configurations of bracing systems, divided into two categories, are explored on a single degree of freedom (SDOF) structure to investigate the feasibility of developing devices for the mitigation of hurricane damage. These bracing devices basically utilize the hysteretic energy dissipation of NiTi resulting from its pseudoelastic characteristic. Since the main goal of this ongoing research is to develop a thorough understanding of the pseudoelastic and hysteretic behavior of SMAs under severe dynamic loading/excitation, a series of earthquake data has been considered as the source of excitation. Through this analysis both the damping and stiffening characteristics of NiTi wires and the effect of these dynamic characteristics on changing the dynamic response of the structure are studied. In the first category the NiTi wires are not pre-strained, while in the second category they are pre-strained. In each category, four different combinations of wire length and modeling of pseudoelastic behavior of NiTi wire are considered. A bilinear stress-strain model is used for representing the pseudoelastic behavior of NiTi tendons, capable of representing internal yield, internal recovery and trigger line concepts. This study establishes that hybrid tendons have the highest damping and stiffening effects on the structure. It is also concluded that, when the amplitude of excitation is small, tendons act as stiffening devices. Once the amplitude of the excitation is large enough to initiate stress-induced phase transformations, tendons act as energy absorption devices. These findings provide very useful information for the development of more effective fastening devices that can withstand severe dynamic loads, such as hurricane loadings.

  13. Training-induced changes in structural and mechanical properties of the patellar tendon are related to muscle hypertrophy but not to strength gains.

    PubMed

    Seynnes, O R; Erskine, R M; Maganaris, C N; Longo, S; Simoneau, E M; Grosset, J F; Narici, M V

    2009-08-01

    To obtain a better understanding of the adaptations of human tendon to chronic overloading, we examined the relationships between these adaptations and the changes in muscle structure and function. Fifteen healthy male subjects (20+/-2 yr) underwent 9 wk of knee extension resistance training. Patellar tendon stiffness and modulus were assessed with ultrasonography, and cross-sectional area (CSA) was determined along the entire length of the tendon by using magnetic resonance imaging. In the quadriceps muscles, architecture and volume measurements were combined to obtain physiological CSA (PCSA), and maximal isometric force was recorded. Following training, muscle force and PCSA increased by 31% (P<0.0001) and 7% (P<0.01), respectively. Tendon CSA increased regionally at 20-30%, 60%, and 90-100% of tendon length (5-6%; P<0.05), and tendon stiffness and modulus increased by 24% (P<0.001) and 20% (P<0.01), respectively. Although none of the tendon adaptations were related to strength gains, we observed a positive correlation between the increase in quadriceps PCSA and the increases in tendon stiffness (r=0.68; P<0.01) and modulus (r=0.75; P<0.01). Unexpectedly, the increase in muscle PCSA was inversely related to the distal and the mean increases in tendon CSA (in both cases, r=-0.64; P<0.05). These data suggest that, following short-term resistance training, changes in tendon mechanical and material properties are more closely related to the overall loading history and that tendon hypertrophy is driven by other mechanisms than those eliciting tendon stiffening. PMID:19478195

  14. Structural and mechanical multi-scale characterization of white New-Zealand rabbit Achilles tendon.

    PubMed

    Kahn, Cyril J F; Dumas, Dominique; Arab-Tehrany, Elmira; Marie, Vanessa; Tran, Nguyen; Wang, Xiong; Cleymand, Franck

    2013-10-01

    Multi-scale characterization of structures and mechanical behavior of biological tissues are of huge importance in order to evaluate the quality of a biological tissue and/or to provide bio-inspired scaffold for functional tissue engineering. Indeed, the more information on main biological tissue structures we get, the more relevant we will be to design new functional prostheses for regenerative medicine or to accurately evaluate tissues. From this perspective, we have investigated the structures and their mechanical properties from nanoscopic to macroscopic scale of fresh ex-vivo white New-Zealand rabbit Achilles tendon using second harmonic generation (SHG) microscopy, atomic force microscopy (AFM) and tensile tests to provide a "simple" model whose parameters are relevant of its micro or nano structure. Thus, collagen fiber's crimping was identified then measured from SHG images as a plane sine wave with 28.4 ± 5.8 μm of amplitude and 141 ± 41 μm of wavelength. Young's moduli of fibrils (3.0 GPa) and amorphous phases (223 MPa) were obtained using TH-AFM. From these investigations, a non-linear Zener model linking a statistical Weibull's distribution of taut fibers under traction to crimp fibers were developed. This model showed that for small strain (<0.1), the amorphous inter-fibrils phase in collagen fibers is more solicited than collagen fibrils themselves. The results open the way to modeled macroscopic mechanical behavior of aligned-crimped collagen soft tissues using multi-scale tendon observations under static or dynamic solicitations. PMID:23811279

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

    PubMed Central

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

    2009-01-01

    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. PMID:19023016

  16. Age-dependent regulation of tendon crimp structure, cell length and gap width with strain.

    PubMed

    Legerlotz, Kirsten; Dorn, Jonas; Richter, Jens; Rausch, Martin; Leupin, Olivier

    2014-10-01

    The black-and-white patterning of tendon fascicles when visualized by light microscopy, also known as crimp, is a well-known feature of fiber-forming collagens. However, not much is known about its development, function and response to strain. The objective of this study is to investigate the interaction of tenocyte and crimp morphology as well as their changes with increasing age and acute strain. In contrast to previous studies, which used indirect measures, such as polarized light, to investigate the crimp structure, this study visualizes internal crimp structure in three dimensions without freezing, sectioning, staining or fixing the tissue, via two-photon imaging of green fluorescent protein expressing cells within mouse tail tendon fascicles. This technique further allows straining of the live tissue while visualizing changes in crimp morphology and cell shape with increasing specimen length. Combining this novel microscopy technique with computational image and data analysis revealed a complex relationship between tenocytes and the extracellular matrix that evolves with increasing age. While the reduction of crimping with strain was observed as expected, most of the crimps were gone at 0-1% strain already. Even relatively low strains of 3% led to pronounced changes in the crimp structure after relaxation, particularly in the young animals, which could not be seen with bright-field imaging. Cell length and gap width increased with strain. However, while the cells were able to return to their original length even after high strains of 6%, the gaps between the cells widened, which may imply modified cell-cell communication after overstretching. PMID:24907659

  17. 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. PMID:17261561

  18. 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).

  19. DOES AEROBIC EXERCISE TRAINING PROMOTE CHANGES IN STRUCTURAL AND BIOMECHANICAL PROPERTIES OF THE TENDONS IN EXPERIMENTAL ANIMALS? A SYSTEMATIC REVIEW

    PubMed Central

    Lemos, A.; Lira, K.D.S.; Silveira, P.V.C.; Coutinho, M.P.G.; e Moraes, S.R.A.

    2012-01-01

    To develop a systematic review to evaluate, through the best scientific evidence available, the effectiveness of aerobic exercise in improving the biomechanical characteristics of tendons in experimental animals. Two independent assessors conducted a systematic search in the databases Medline/PUBMED and Lilacs/BIREME, using the following descriptors of Mesh in animal models. The ultimate load of traction and the elastic modulus tendon were used as primary outcomes and transverse section area, ultimate stress and tendon strain as secondary outcomes. The assessment of risk of bias in the studies was carried out using the following methodological components: light/dark cycle, temperature, nutrition, housing, research undertaken in conjunction with an ethics committee, randomization, adaptation of the animals to the training and preparation for the mechanical test. Eight studies, comprising 384 animals, were selected; it was not possible to combine them into one meta-analysis due to the heterogeneity of the samples. There was a trend to increasing ultimate load without changes in the other outcomes studied. Only one study met more than 80% of the quality criteria. Physical training performed in a structured way with imposition of overloads seems to be able to promote changes in tendon structure of experimental models by increasing the ultimate load supported. However, the results of the influence of exercise on the elastic modulus parameters, strain, transverse section area and ultimate stress, remain controversial and inconclusive. Such a conclusion must be evaluated with reservation as there was low methodological control in the studies included in this review. PMID:24868114

  20. Effect of PNF stretching training on the properties of human muscle and tendon structures.

    PubMed

    Konrad, A; Gad, M; Tilp, M

    2015-06-01

    The purpose of this study was to investigate the influence of a 6-week proprioceptive neuromuscular facilitation (PNF) stretching training program on the various parameters of the human gastrocnemius medialis muscle and the Achilles tendon. Therefore, 49 volunteers were randomly assigned into PNF stretching and control groups. Before and after the stretching intervention, we determined the maximum dorsiflexion range of motion (RoM) with the corresponding fascicle length and pennation angle. Passive resistive torque (PRT) and maximum voluntary contraction (MVC) of the musculo-articular complex were measured with a dynamometer. Muscle-tendon junction (MTJ) displacement allowed us to determine the length changes in tendon and muscle, and hence to calculate stiffness. Mean RoM increased from 31.1?±?7.2° to 33.1?±?7.2° (P?=?0.02), stiffness of the tendon decreased significantly in both active (from 21.1?±?8.0 to 18.1?±?5.5?N/mm) and passive (from 12.1?±?4.9 to 9.6?±?3.2?N/mm) conditions, and the pennation angle increased from 18.5?±?1.8° to 19.5?±?2.1° (P?=?0.01) at the neutral ankle position (90°), only in the intervention group, whereas MVC and PRT values remained unchanged. We conclude that a 6-week PNF stretching training program increases RoM and decreases tendon stiffness, despite no change in PRT. PMID:24716522

  1. Histopathological findings in chronic tendon disorders.

    PubMed

    Järvinen, M; Józsa, L; Kannus, P; Järvinen, T L; Kvist, M; Leadbetter, W

    1997-04-01

    Tendon injuries and other tendon disorders represent a common diagnostic and therapeutic challenge in sports medicine, resulting in chronic and long-lasting problems. Tissue degeneration is a common finding in many sports-related tendon complaints. In the great majority of spontaneous tendon ruptures, chronic degenerative changes are seen at the rupture site of the tendon (1). Systemic diseases and diseases specifically deteriorating the normal structure of the tendon (i.e. foreign bodies, and metabolic, inherited and infectious tendon diseases) are only rarely the cause of tendon pathology. Inherited diseases, such as various hereditary diseases with disturbed collagen metabolism and characteristic pathological structural alterations (Ehlers-Danlos syndrome, Marfani syndrome, homocystinuria (ochronosis)), represent approximately 1% of the causes of chronic tendon complaints (2), whereas foreign bodies are somewhat more common and are found in less than 10% of all chronic tendon problems (1). Rheumatoid arthritis and sarcoidosis are typical systemic diseases that cause chronic inflammation in tendon and peritendinous tissues. Altogether, these 'specific' disorders represented less than 2% of the pathological alterations found in the histological analysis of more than 1000 spontaneously ruptured tendons (1, 3, 4). In this material, degenerative changes were seen in a great majority of the tendons, indicating that a spontaneous tendon rupture is a typical clinical end-state manifestation of a degenerative process in the tendon tissue. The role of overuse in the pathogenesis of chronic tendon injuries and disorders is not completely understood. It has been speculated that when tendon is overused it becomes fatigued and loses its basal reparative ability, the repetitive microtraumatic processes thus overwhelming the ability of the tendon cells to repair the fiber damage. The intensive repetitive activity, which often is eccentric by nature, may lead to cumulative microtrauma which further weakens the collagen cross-linking, non-collagenous matrix, and vascular elements of the tendon. Overuse has also been speculated to cause chronic tendon problems, by disturbing the micro- and macrovasculature of the tendon and resulting in insufficiency in the local blood circulation. Decreased blood flow simultaneous with an increased activity may result in local tissue hypoxia, impaired nutrition and energy metabolism, and together these factors are likely to play an important role in the sequence of events leading to tendon degeneration (4). A sedentary lifestyle has been proposed as a main reason for poor basal circulation of the tendon, and presumably is at least partly responsible for the high number of tendon problems in people with a sedentary lifestyle who occasionally take part in high physical activity sports events. PMID:9211609

  2. Achilles Tendonitis

    MedlinePLUS

    ... Plan Hot Topics Meningitis Choosing Your Mood Prescription Drug Abuse Healthy School Lunch Planner How Can I Help ... or intense strain on the tendon. But non-athletes also can get it if they put a ...

  3. Tendon repair

    MedlinePLUS

    Tendon repair can be performed using: Local anesthesia (the immediate area of the surgery is pain-free) Regional anesthesia (the local and surrounding areas are pain-free) General anesthesia (the patient ...

  4. Effect of fatigue loading on structure and functional behaviour of fascicles from energy-storing tendons.

    PubMed

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

    2014-07-01

    Tendons can broadly be categorized according to their function: those that act purely to position the limb and those that have an additional function as energy stores. Energy-storing tendons undergo many cycles of large deformations during locomotion, and so must be able to extend and recoil efficiently, rapidly and repeatedly. Our previous work has shown rotation in response to applied strain in fascicles from energy-storing tendons, indicating the presence of helical substructures which may provide greater elasticity and recovery. In the current study, we assessed how preconditioning and fatigue loading affect the ability of fascicles from the energy-storing equine superficial digital flexor tendon to extend and recoil. We hypothesized that preconditioned samples would exhibit changes in microstructural strain response, but would retain their ability to recover. We further hypothesized that fatigue loading would result in sample damage, causing further alterations in extension mechanisms and a significant reduction in sample recovery. The results broadly support these hypotheses: preconditioned samples showed some alterations in microstructural strain response, but were able to recover following the removal of load. However, fatigue loaded samples showed visual evidence of damage and exhibited further alterations in extension mechanisms, characterized by decreased rotation in response to applied strain. This was accompanied by increased hysteresis and decreased recovery. These results suggest that fatigue loading results in a compromised helix substructure, reducing the ability of energy-storing tendons to recoil. A decreased ability to recoil may lead to an impaired response to further loading, potentially increasing the likelihood of injury. PMID:24747261

  5. Tenascin-C and human tendon degeneration.

    PubMed

    Riley, G P; Harrall, R L; Cawston, T E; Hazleman, B L; Mackie, E J

    1996-09-01

    We investigated the distribution of tenascin in supraspinatus tendons to determine whether an alteration in tenascin expression was associated with human tendon degeneration. Tenascin was present in all of the tendons studied, although with two distinct patterns of expression. First, tenascin was associated with organized, fibrous regions of the tendon matrix that were typical of the normal tendon structure. This distribution is consistent with a role for tenascin in collagen fibril organization, perhaps maintaining the interface between fibrils and adjacent structures. Second, although tenascin was generally absent from poorly organized matrix in degenerate tendons, it was strongly associated with some rounded cells in disorganized fibrocartilaginous regions that were more abundant in pathological specimens. Tenascin was also found around infiltrating blood vessels, with more intense staining associated with a mononuclear cell infiltrate. Western blotting of tendon extracts showed differences in tenascin isoform expression, with only the small (200-kd) tenascin isoform found in normal tendons. Degenerate tendons also expressed the 300-kd isoform, consistent with a role for the larger tenascin isoform in tendon disease, potentially stimulating tenocyte proliferation, cell rounding, and fibrocartilaginous change. Proteolytic fragments of tenascin were detected but only in ruptured tendons, an indication of matrix remodeling in degenerate tendons, with fragment sizes consistent with the activity of matrix metalloproteinase enzymes. PMID:8780397

  6. Jones Tendon Transfer.

    PubMed

    Derner, Richard; Holmes, Jeffrey

    2016-01-01

    Hallux malleus is a deformity of the great toe. There is a dorsiflexion contracture at the metatarsophalangeal joint and plantar flexion of the interphalangeal joint. The deformity is commonly attributed to muscular imbalances of the various structures acting on the great toe. Jones tendon transfer is a procedure used to remove the deforming force to the clawed hallux. It is most often performed in conjunction with a hallux interphalangeal joint fusion. Typically there is a neurologic component causing a deformity to the entire foot, necessitating adjunct procedures. The Jones tendon transfer has shown to have reproducible results. PMID:26590724

  7. Periosteal augmentation of a tendon graft improves tendon healing in the bone tunnel.

    PubMed

    Youn, Inchan; Jones, Deryk G; Andrews, Pamela J; Cook, Marcus P; Suh, J-K Francis

    2004-02-01

    Secure fixation of tendon or ligament to bone has been a challenging problem. The periosteum is an osteogenic organ that regulates bone growth and remodeling at the outer surface of cortical bone and also is known to play an important role in forming a tendon insertion site to bone. Therefore, we hypothesized that a freshly harvested periosteum can be used as a stimulative scaffold to biologically reinforce the attachment of tendon graft to bone. Using a rabbit hallucis longus tendon and calcaneus process model, we found that a periosteal augmentation of a tendon graft could enhance the structural integrity of the tendon-bone interface, when the periosteum is placed between the tendon and bone interface with the cambium layer facing toward the bone. Clinically, the use of an autogenous periosteum patch would be an optimal choice for biologic augmentation of the tendon graft in the bone tunnel, because the tissue is readily available for harvest from the patient's body. PMID:15021159

  8. Pes Anserinus Structural Framework and Constituting Tendons Are Grossly Aberrant in Nigerian Population.

    PubMed

    Ashaolu, J O; Osinuga, T S; Ukwenya, V O; Makinde, E O; Adekanmbi, A J

    2015-01-01

    We evaluated the morphological framework of the pes anserinus in both knees of ten Nigerian cadavers and we observed high degree of variability in its morphology and location. The pes anserinus inserted specifically on the superior half of the media border of the tibia, as far inferiorly as 124.44?mm to the tibial tuberosity (prolonged insertion). The insertion was also joined to the part of tibia close to the tibia tuberosity (90%) and to the fascia cruris (10%). The initial insertion point of the pes anserinus was always found at the level of the tibia tuberosity. We found out that accessory bands of sartorius, gracilis, or semitendinosus were part of the pes anserinus in 95% of all occasions studied whereas the combined occurrence of monotendinosus sartorius, gracilis, and semitendinosus tendons was found in only 5% of all occasions. The pes anserinus did not conform to the layered pattern and the tendons of sartorius, gracilis, or semitendinosus were short. The inferior prolongation of the pes anserinus connotes extended surface area of attachment to support the mechanical pull from the hamstring muscles. This information will be useful in precise location and grafting of the pes anserinus. PMID:26246910

  9. 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. PMID:24414293

  10. 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

  11. 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

  12. On the mechanical function of tendon.

    PubMed

    Kafka, V; Jírová, J; Smetana, V

    1995-01-01

    A mesoscopic approach is followed for mathematical modelling of the specific deformation properties of tendon. The approach starts from our general concept of modelling mechanical behaviour of heterogeneous media and assumes that the structure of tendon is optimized in such a way that it enables its adjacent muscle to work with a constant performance in the course of increasing loading (acting like a gearbox in a car). The model based on this assumption gives results that are in a very good accordance with observed properties of tendons. Clinical experience reveals that if this function of tendon is violated pathological changes appear in the respective muscle. RELEVANCE: Clarification and mathematical modelling of the mechanical function of tendon is of intellectual interest in its own right, but it is important also for cautioning surgeons against unnecessary violation of this function, and for tissue engineering aspects if tendon must be replaced. PMID:11415531

  13. Traumatic flexor tendon injuries.

    PubMed

    Lapegue, F; Andre, A; Brun, C; Bakouche, S; Chiavassa, H; Sans, N; Faruch, M

    2015-12-01

    The flexor system of the fingers consisting of flexor tendons and finger pulleys is a key anatomic structure for the grasping function. Athletes and manual workers are particularly at risk for closed injuries of the flexor system: ruptured pulleys, ruptures of the flexor digitorum profundus from its distal attachment ("jersey finger"), and less frequently, ruptures of the flexor digitorum superficialis and of the lumbrical muscles. Open injuries vary more and their imaging features are more complex since tendons may be torn in several locations, the locations may be unusual, the injuries may be associated with nerve and vascular injuries, fibrosis… Sonography is the best imaging modality to associate with the clinical exam for it allows an experienced physician to make an accurate and early diagnosis, crucial to appropriate early treatment planning. PMID:26564614

  14. The histological structure of the malleolar groove of the fibula in man: its direct bearing on the displacement of peroneal tendons and their surgical repair

    PubMed Central

    Kumai, T; Benjamin, M

    2003-01-01

    The peroneal (fibularis) tendons are held in place within the malleolar groove by the superior peroneal retinaculum. If this is torn, the tendons can subluxate or dislocate. Understanding the anatomy of the region is important for treating these injuries when it becomes necessary to reconstruct the malleolar groove surgically. Serial transverse sections of the groove were cut from 10 dissecting room cadavers after routine histology processing. The structure of the malleolar groove differed significantly in its proximal and distal parts. Distally, the bone is convex and the shape of the groove is determined by a thick periosteal cushion of fibrocartilage that covers the bone surface. Proximally, the groove shape is determined by the bone itself, and the periosteum is thin and fibrous. The restriction of a periosteal fibrocartilage to the distal end suggests that it serves to adapt the shape of the malleolar groove to that of the tendons within it and thus promotes stress dissipation. Paradoxically, however, it increases the risk of damage to subluxated tendons, because these can be sliced longitudinally by a sharp ridge created from periosteal fibrocartilage when the retinaculum is torn. Our results suggest that if bone-block surgical procedures are used to reconstruct the malleolar groove, they are best restricted to its proximal part. PMID:12924825

  15. Shear Load Transfer in High and Low Stress Tendons

    PubMed Central

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

    2016-01-01

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

  16. Fibrin Gels Exhibit Improved Biological, Structural, and Mechanical Properties Compared with Collagen Gels in Cell-Based Tendon Tissue-Engineered Constructs

    PubMed Central

    Dyment, Nathaniel A.; Lu, Yinhui; Rao, Marepalli; Shearn, Jason T.; Rowe, David W.; Kadler, Karl E.; Butler, David L.

    2015-01-01

    The prevalence of tendon and ligament injuries and inadequacies of current treatments is driving the need for alternative strategies such as tissue engineering. Fibrin and collagen biopolymers have been popular materials for creating tissue-engineered constructs (TECs), as they exhibit advantages of biocompatibility and flexibility in construct design. Unfortunately, a few studies have directly compared these materials for tendon and ligament applications. Therefore, this study aims at determining how collagen versus fibrin hydrogels affect the biological, structural, and mechanical properties of TECs during formation in vitro. Our findings show that tendon and ligament progenitor cells seeded in fibrin constructs exhibit improved tenogenic gene expression patterns compared with their collagen-based counterparts for approximately 14 days in culture. Fibrin-based constructs also exhibit improved cell-derived collagen alignment, increased linear modulus (2.2-fold greater) compared with collagen-based constructs. Cyclic tensile loading, which promotes the maturation of tendon constructs in a previous work, exhibits a material-dependent effect in this study. Fibrin constructs show trending reductions in mechanical, biological, and structural properties, whereas collagen constructs only show improved tenogenic expression in the presence of mechanical stimulation. These findings highlight that components of the mechanical stimulus (e.g., strain amplitude or time of initiation) need to be tailored to the material and cell type. Given the improvements in tenogenic expression, extracellular matrix organization, and material properties during static culture, in vitro findings presented here suggest that fibrin-based constructs may be a more suitable alternative to collagen-based constructs for tissue-engineered tendon/ligament repair. PMID:25266738

  17. Functional Tissue Engineering of Tendon: Establishing Biological Success Criteria for Improving Tendon Repair

    PubMed Central

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

    2013-01-01

    Improving tendon repair using Functional Tissue Engineering (FTE) principles has been the focus of our laboratory over the last decade. Although our primary goals were initially focused only on mechanical outcomes, we are now carefully assessing the biological properties of our tissue-engineered tendon repairs so as to link biological influences with mechanics. However, given the complexities of tendon development and healing, it remains challenging to determine which aspects of tendon biology are the most important to focus on in the context of tissue engineering. To address this problem, we have formalized a strategy to identify, prioritize, and evaluate potential biological success criteria for tendon repair. We have defined numerous biological properties of normal tendon relative to cellular phenotype, extracellular matrix and tissue ultra-structure that we would like to reproduce in our tissue-engineered repairs and prioritized these biological criteria by examining their relative importance during both normal development and natural tendon healing. Here, we propose three specific biological criteria which we believe are essential for normal tendon function: 1) scleraxis-expressing cells; 2) well-organized and axially-aligned collagen fibrils having bimodal diameter distribution; and 3) a specialized tendon-to-bone insertion site. Moving forward, these biological success criteria will be used in conjunction with our already established mechanical success criteria to evaluate the effectiveness of our tissue-engineered tendon repairs. PMID:24200342

  18. 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. PMID:17703588

  19. 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. PMID:24534664

  20. Transverse Compression of Tendons.

    PubMed

    Samuel Salisbury, S T; Paul Buckley, C; 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. PMID:26833218

  1. Tendon development and diseases.

    PubMed

    Gaut, Ludovic; Duprez, Delphine

    2016-01-01

    Tendon is a uniaxial connective tissue component of the musculoskeletal system. Tendon is involved in force transmission between muscle and bone. Tendon injury is very common and debilitating but tendon repair remains a clinical challenge for orthopedic medicine. In vertebrates, tendon is mainly composed of type I collagen fibrils, displaying a parallel organization along the tendon axis. The tendon-specific spatial organization of type I collagen provides the mechanical properties for tendon function. In contrast to other components of the musculoskeletal system, tendon biology is poorly understood. An important goal in tendon biology is to understand the mechanisms involved in the production and assembly of type I collagen fibrils during development, postnatal formation, and healing processes in order to design new therapies for tendon repair. In this review we highlight the current understanding of the molecular and mechanical signals known to be involved in tenogenesis during development, and how development provides insights into tendon healing processes. WIREs Dev Biol 2016, 5:5-23. doi: 10.1002/wdev.201 For further resources related to this article, please visit the WIREs website. PMID:26256998

  2. Achilles tendon rupture - aftercare

    MedlinePLUS

    ... MRI scan to see what type of Achilles tendon tear you have. An MRI is a type of ... partial tear means at least some of the tendon is still OK. A full tear means your tendon is torn completely and the ...

  3. 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 be taken with caution, following a targeted rehabilitation program. However, further research should be performed to fully understand the effect of sudden detraining on tendons. PMID:26973517

  4. 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. PMID:25647652

  5. The role of animal models in tendon research.

    PubMed

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

    2014-06-01

    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

  6. 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

  7. Multi-Layer Electrospun Membrane Mimicking Tendon Sheath for Prevention of Tendon Adhesions

    PubMed Central

    Jiang, Shichao; Yan, Hede; Fan, Dapeng; Song, Jialin; Fan, Cunyi

    2015-01-01

    Defect of the tendon sheath after tendon injury is a main reason for tendon adhesions, but it is a daunting challenge for the biomimetic substitute of the tendon sheath after injury due to its multi-layer membrane-like structure and complex biologic functions. In this study, a multi-layer membrane with celecoxib-loaded poly(l-lactic acid)-polyethylene glycol (PELA) electrospun fibrous membrane as the outer layer, hyaluronic acid (HA) gel as middle layer, and PELA electrospun fibrous membrane as the inner layer was designed. The anti-adhesion efficacy of this multi-layer membrane was compared with a single-layer use in rabbit flexor digitorum profundus tendon model. The surface morphology showed that both PELA fibers and celecoxib-loaded PELA fibers in multi-layer membrane were uniform in size, randomly arrayed, very porous, and smooth without beads. Multi-layer membrane group had fewer peritendinous adhesions and better gliding than the PELA membrane group and control group in gross and histological observation. The similar mechanical characteristic and collagen expression of tendon repair site in the three groups indicated that the multi-layer membrane did not impair tendon healing. Taken together, our results demonstrated that such a biomimetic multi-layer sheath could be used as a potential strategy in clinics for promoting tendon gliding and preventing adhesion without poor tendon healing. PMID:25822877

  8. Tendon matrix composition and turnover in relation to functional requirements.

    PubMed

    Birch, Helen L

    2007-08-01

    Tendons are dense regular connective tissue structures that are defined based on their anatomical position of connecting muscle to bone. Despite these obvious commons features tendons from different locations within the body show remarkable variation in terms of their morphological, molecular and mechanical properties which relates to their specialized function. An appreciation of these differences is necessary to understand all aspects of tendon biology in health and disease. In our work, we have used a combination of mechanical assessment, histological measurements and molecular analysis of matrix in functionally distinct tendons to determine relationships between function and structure. We have found significant differences in material and molecular properties between spring-like tendons that are subjected to high strains during locomotion and positional tendons which are subjected to much lower strains. Furthermore, we have data to suggest that not only is the matrix composition different but also the ability of cells to synthesize and degrade the matrix (matrix turnover) varies between tendon types. We propose that these differences relate to the magnitude of strain that the tendon experiences during normal activities in life. Tendon cells may be preprogrammed during embryological development for the strain they will encounter in life or may simply respond to the particular strain environment they are subjected to. The elucidation of controlling mechanisms resulting in tendon cell specialization will have important consequences for cell based therapies and engineering strategies to repair damaged tendons. PMID:17696905

  9. 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.

  10. Tendon functional extracellular matrix.

    PubMed

    Screen, Hazel R C; Berk, David E; Kadler, Karl E; Ramirez, Francesco; Young, Marian F

    2015-06-01

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

  11. THE ROLE OF MECHANOBIOLOGY IN TENDON HEALING

    PubMed Central

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

    2011-01-01

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

  12. Avoiding Anomalous Tendon Harvest at the Pes Anserinus Insertion.

    PubMed

    Cidambi, Krishna R; Pennock, Andrew T; Dwek, Jerry R; Edmonds, Eric W

    2016-01-01

    The purpose of this study was to identify the frequency and characteristics of anomalous pes anserinus tendon morphology in an adolescent population undergoing knee anterior cruciate ligament (ACL) reconstruction surgery. The records of all children who underwent ACL reconstruction surgery at our tertiary care children's hospital from June 2008 through February 2012 were reviewed. Operative reports were reviewed for any indication that an anomaly existed in the pes anserinus or that there was difficulty harvesting the required tendons. Magnetic resonance imaging (MRI) studies were then reviewed for these patients looking for evidence of any anomaly within the pes anserinus structures. Retrospective review was performed on 123 children (mean age, 16.1 years). Three girls (mean age, 16.2 years) were identified as having a low-lying muscle belly and accessory tendon when attempting to harvest the gracilis tendon. Proximal exploration of this short tendon conjoining the gracilis insertion revealed a muscle belly approximately 5 cm from its insertion in the pes anserinus. This anomaly was present in 2.4% of the cases. Based on previous literature, the anomalous muscle present in our cohort could be sartorius or semimembranosus. MRI analysis suggests that the accessory muscle and tendon could be an aberrant strip of the semimembranosus tendon, an anomalous tendon and muscle belly of the gracilis, or a thickening and separation of the sartorius tendon. Anomalous pes anserinus tendons were found to exist in 2.4% of our adolescent study population. At the time of surgery, if a tendon is harvested with a very low-lying muscle belly (with less than 6 cm of tendon), then the presence of an aberrant tendon should be considered. Preoperative MRI may provide evidence of an anomalous tendon if that information is sought. PMID:25556897

  13. 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. PMID:17229278

  14. Fatigue loading of tendon

    PubMed Central

    Shepherd, Jennifer H; Screen, Hazel R C

    2013-01-01

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

  15. Peroneal Tendon Injuries

    MedlinePLUS

    ... ACFAS | Información en Español Advanced Search Home » Foot & Ankle Conditions » Peroneal Tendon Injuries Text Size Print Bookmark ... foot run side-by-side behind the outer ankle bone. One peroneal tendon attaches to the outer ...

  16. Fibrocartilage associated with human tendons and their pulleys.

    PubMed Central

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

    1995-01-01

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

  17. The Achilles tendon: fundamental properties and mechanisms governing healing

    PubMed Central

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

    2014-01-01

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

  18. 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

  19. 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

  20. A conceptual framework for computational models of Achilles tendon homeostasis.

    PubMed

    Smith, David W; Rubenson, Jonas; Lloyd, David; Zheng, Minghao; Fernandez, Justin; Besier, Thor; Xu, Jiake; Gardiner, Bruce S

    2013-01-01

    Computational modeling of tendon lags the development of computational models for other tissues. A major bottleneck in the development of realistic computational models for Achilles tendon is the absence of detailed conceptual and theoretical models as to how the tissue actually functions. Without the conceptual models to provide a theoretical framework to guide the development and integration of multiscale computational models, modeling of the Achilles tendon to date has tended to be piecemeal and focused on specific mechanical or biochemical issues. In this paper, we present a new conceptual model of Achilles tendon tissue homeostasis, and discuss this model in terms of existing computational models of tendon. This approach has the benefits of structuring the research on relevant computational modeling to date, while allowing us to identify new computational models requiring development. The critically important functional issue for tendon is that it is continually damaged during use and so has to be repaired. From this follows the centrally important issue of homeostasis of the load carrying collagen fibrils within the collagen fibers of the Achilles tendon. Collagen fibrils may be damaged mechanically-by loading, or damaged biochemically-by proteases. Upon reviewing existing computational models within this conceptual framework of the Achilles tendon structure and function, we demonstrate that a great deal of theoretical and experimental research remains to be done before there are reliably predictive multiscale computational model of Achilles tendon in health and disease. PMID:23757159

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

    PubMed

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

    2016-02-01

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

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

    PubMed Central

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

    2016-01-01

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

  3. Posterior Tibial Tendon Dysfunction

    MedlinePLUS

    ... helpful. This patient is able to perform a single limb heel rise on the right leg. Magnetic resonance imaging (MRI). These studies can create images of so tissues like the tendons and muscles. ...

  4. 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 ...

  5. 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 ...

  6. The tendons: Interventional sonography

    PubMed Central

    Campagna, R.; Guerini, H.

    2012-01-01

    While blind or fluoroscopically guided infiltration works well for intra-articular injections, injections into the tendon sheath are much more difficult. Ultrasound guidance with high-frequency transducers now allows visualization and infiltration of tendon sheaths. The interventional phase should be preceded by a diagnostic scan. Patients should be questioned to identify possible contraindications to the procedure and informed of the potential risks. Strict asepsis must be maintained for both patient and operator. This review includes separate discussions of the tendons in different areas of the body that are most commonly treated with ultrasound-guided injections, with descriptions of the lesions that are treated and the approach used for each. Interventional sonography is currently the only technique that allows visualization of the tendon being infiltrated. It requires training and experience as well as good knowledge of the indications and equipment used for the procedures, and the anatomy of the areas being treated. PMID:23396899

  7. Achilles Tendon Disorders.

    PubMed

    Saini, Sundeep S; Reb, Christopher W; Chapter, Megan; Daniel, Joseph N

    2015-11-01

    Disorders of the Achilles tendon, the largest tendon in the human body, are common and occur in both active and sedentary persons. A thorough history and physical examination allow primary care physicians to make an accurate diagnosis and to initiate appropriate management. Mismanaged or neglected injuries markedly decrease a patient's quality of life. A growing body of related literature is the basis for current therapeutic regimens, which use a multimodal conservative approach, including osteopathic manipulative treatment. Although primary care physicians can manage most cases of Achilles tendon disorders, specialty care may be needed in certain instances. Procedural intervention should consider any comorbid conditions in addition to patients' lifestyle to help guide decision making. When appropriately managed, Achilles tendon disorders generally carry a favorable prognosis. PMID:26501760

  8. Subrupture Tendon Fatigue Damage

    PubMed Central

    Laudier, Damien M.; Shine, Jean H.; Basta-Pljakic, Jelena; Jepsen, Karl J.; Schaffler, Mitchell B.; Flatow, Evan L.

    2016-01-01

    The mechanical and microstructural bases of tendon fatigue, by which damage accumulates and contributes to degradation, are poorly understood. To investigate the tendon fatigue process, rat flexor digitorum longus tendons were cyclically loaded (1–16 N) until reaching one of three levels of fatigue damage, defined as peak clamp-to-clamp strain magnitudes representing key intervals in the fatigue life: i) Low (6.0%–7.0%); ii) Moderate (8.5%–9.5%); and iii) High (11.0%–12.0%). Stiffness, hysteresis, and clamp-to-clamp strain were assessed diagnostically (by cyclic loading at 1–8 N) before and after fatigue loading and following an unloaded recovery period to identify mechanical parameters as measures of damage. Results showed that tendon clamp-to-clamp strain increased from pre- to post-fatigue loading significantly and progressively with the fatigue damage level (p≤0.010). In contrast, changes in both stiffness and hysteresis were significant only at the High fatigue level (p≤0.043). Correlative microstructural analyses showed that Low level of fatigue was characterized by isolated, transverse patterns of kinked fiber deformations. At higher fatigue levels, tendons exhibited fiber dissociation and localized ruptures of the fibers. Histomorphometric analysis showed that damage area fraction increased significantly with fatigue level (p≤0.048). The current findings characterized the sequential, microstructural events that underlie the tendon fatigue process and indicate that tendon deformation can be used to accurately assess the progression of damage accumulation in tendons. PMID:18683881

  9. Modelling approaches for evaluating multiscale tendon mechanics.

    PubMed

    Fang, Fei; Lake, Spencer P

    2016-02-01

    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. Anatomical heterogeneity of tendon: Fascicular and interfascicular tendon compartments have distinct proteomic composition.

    PubMed

    Thorpe, Chavaunne T; Peffers, Mandy J; Simpson, Deborah; Halliwell, Elizabeth; Screen, Hazel R C; Clegg, Peter D

    2016-01-01

    Tendon is a simple aligned fibre composite, consisting of collagen-rich fascicles surrounded by a softer interfascicular matrix (IFM). The composition and interactions between these material phases are fundamental in ensuring tissue mechanics meet functional requirements. However the IFM is poorly defined, therefore tendon structure-function relationships are incompletely understood. We hypothesised that the IFM has a more complex proteome, with faster turnover than the fascicular matrix (FM). Using laser-capture microdissection and mass spectrometry, we demonstrate that the IFM contains more proteins, and that many proteins show differential abundance between matrix phases. The IFM contained more protein fragments (neopeptides), indicating greater matrix degradation in this compartment, which may act to maintain healthy tendon structure. Protein abundance did not alter with ageing, but neopeptide numbers decreased in the aged IFM, indicating decreased turnover which may contribute to age-related tendon injury. These data provide important insights into how differences in tendon composition and turnover contribute to tendon structure-function relationships and the effects of ageing. PMID:26842662

  11. Anatomical heterogeneity of tendon: Fascicular and interfascicular tendon compartments have distinct proteomic composition

    PubMed Central

    Thorpe, Chavaunne T.; Peffers, Mandy J.; Simpson, Deborah; Halliwell, Elizabeth; Screen, Hazel R. C.; Clegg, Peter D.

    2016-01-01

    Tendon is a simple aligned fibre composite, consisting of collagen-rich fascicles surrounded by a softer interfascicular matrix (IFM). The composition and interactions between these material phases are fundamental in ensuring tissue mechanics meet functional requirements. However the IFM is poorly defined, therefore tendon structure-function relationships are incompletely understood. We hypothesised that the IFM has a more complex proteome, with faster turnover than the fascicular matrix (FM). Using laser-capture microdissection and mass spectrometry, we demonstrate that the IFM contains more proteins, and that many proteins show differential abundance between matrix phases. The IFM contained more protein fragments (neopeptides), indicating greater matrix degradation in this compartment, which may act to maintain healthy tendon structure. Protein abundance did not alter with ageing, but neopeptide numbers decreased in the aged IFM, indicating decreased turnover which may contribute to age-related tendon injury. These data provide important insights into how differences in tendon composition and turnover contribute to tendon structure-function relationships and the effects of ageing. PMID:26842662

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

    PubMed Central

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

    2013-01-01

    Summary Tendons and ligaments are similar structures in terms of their composition, organisation and mechanical properties. The distinction between them stems from their anatomical location; tendons form a link between muscle and bone while ligaments link bones to bones. A range of overlapping functions can be assigned to tendon and ligaments and each structure has specific mechanical properties which appear to be suited for particular in vivo function. The extracellular matrix in tendon and ligament varies in accordance with function, providing appropriate mechanical properties. The most useful framework in which to consider extracellular matrix differences therefore is that of function rather than anatomical location. In this review we discuss what is known about the relationship between functional requirements, structural properties from molecular to gross level, cellular gene expression and matrix turnover. The relevance of this information is considered by reviewing clinical aspects of tendon and ligament repair and reconstructive procedures. PMID:23885341

  13. 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

  14. [Achilles tendon rupture].

    PubMed

    Thermann, H; Hüfner, T; Tscherne, H

    2000-03-01

    The treatment of acute of Achilles tendon rupture experienced a dynamic development in the last ten years. Decisive for this development was the application of MRI and above all the ultrasonography in the diagnostics of the pathological changes and injuries of tendons. The question of rupture morphology as well as different courses of healing could be now evaluated objectively. These advances led consequently to new modalities in treatment concepts and rehabilitation protocols. The decisive input for improvements of the outcome results and particularly the shortening of the rehabilitation period came with introduction of the early functional treatment in contrast to immobilizing plaster treatment. In a prospective randomized study (1987-1989) at the Trauma Dept. of the Hannover Medical School could show no statistical differences comparing functional non-operative with functional operative therapy with a special therapy boot (Variostabil/Adidas). The crucial criteria for therapy selection results from the sonographically measured position of the tendon stumps in plantar flexion (20 degrees). With complete adaptation of the tendons' ends surgical treatment does not achieve better results than non-operative functional treatment in term of tendon healing and functional outcome. Regarding the current therapeutic standards each method has is advantages and disadvantages. Both, the operative and non-operative functional treatment enable a stable tendon healing with a low risk of re-rupture (1-2%). Meanwhile there is consensus for early functional after-treatment of the operated Achilles' tendons. There seems to be a trend towards non-operative functional treatment in cases of adequate sonographical findings, or to minimal invasive surgical techniques. PMID:10798233

  15. 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.

  16. Tibialis Anterior Tendon Transfer.

    PubMed

    Mulhern, Jennifer L; Protzman, Nicole M; Brigido, Stephen A

    2016-01-01

    Tendon transfer procedures are used commonly for the correction of soft tissue imbalances and instabilities. The complete transfer and the split transfer of the tibialis anterior tendon are well-accepted methods for the treatment of idiopathic equinovarus deformity in children and adults. Throughout the literature, complete and split transfer have been shown to yield significant improvements in ankle and foot range of motion and muscle function. At present, there is insufficient evidence to recommend one procedure over the other, although the split procedure has been advocated for consistently achieving inversion to eversion muscle balance without overcorrection. PMID:26590723

  17. Posterior Tibial Tendon Transfer.

    PubMed

    Shane, Amber M; Reeves, Christopher L; Cameron, Jordan D; Vazales, Ryan

    2016-01-01

    When performed correctly with the right patient population, a tibialis posterior muscle/tendon transfer is an effective procedure. Many different methods have been established for fixating the tendon, each of which has its' own indications. Passing through the interosseous membrane is the preferred and recommended method and should be used unless this is not possible. Good surgical planning based on patient needs and expectations, along with excellent postoperative care including early range of motion and physical therapy minimizes risk of complications and allows for the optimal outcome to be achieved. PMID:26590722

  18. Distal Triceps Tendon Injuries.

    PubMed

    Keener, Jay D; Sethi, Paul M

    2015-11-01

    Acute triceps ruptures are an uncommon entity, occurring mainly in athletes, weight lifters (especially those taking anabolic steroids), and following elbow trauma. Accurate diagnosis is made clinically, although MRI may aid in confirmation and surgical planning. Acute ruptures are classified on an anatomic basis based on tear location and the degree of tendon involvement. Most complete tears are treated surgically in medically fit patients. Partial-thickness tears are managed according to the tear severity, functional demands, and response to conservative treatment. We favor an anatomic footprint repair of the triceps to provide optimal tendon to bone healing and, ultimately, functional outcome. PMID:26498552

  19. 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. PMID:23599401

  20. Experimental studies in chickens on the initial nutrition of tendon grafts.

    PubMed

    Manske, P R; Lesker, P A; Bridwell, K

    1979-11-01

    A study of nutrition of various tendon graft preparations in adult chickens (up to 2 weeks after grafting), using tritiated proline and a trichloracetic acid extraction technique which separated the free and metabolized amino acid fractions, suggests that diffusion of nutrients is an important process in the initial nutrition of tendon grafts, that tendon grafts are metabolically active and viable structures, that adhesions which are frequently associated with tendon grafts do not appear to be essential to the nutrition of grafts, and that tendon grafts within fibrous pseudosheaths are nourished as effectively as grafts within synovial sheaths. PMID:512314

  1. Proximal Biceps Tendonitis

    MedlinePLUS

    ... of biceps tendonitis, make sure you know the right way to play. Playing in the wrong way can put your arm in weird positions ... consult your doctor. © 1995- The Nemours Foundation. All rights ... Veer, Science Photo Library, Science Source Images, Shutterstock, and Clipart. ...

  2. Flexor tendon surgery. Part 2: Free tendon grafts and tenolysis.

    PubMed

    Strickland, J W

    1989-11-01

    We have attempted to review the development and current status of flexor tendon surgery. The methods of acute flexor tendon repair, conventional free tendon grafting, staged flexor tendon reconstruction, tenolysis and pulley restoration have been discussed, with the published results included for each procedure. The role of rehabilitation has also been reviewed and the ongoing quest for an active flexor tendon prosthetic implant has been briefly mentioned. 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 surgery and a strong understanding of the techniques which may be best utilised to restore tendon gliding and digital joint motion. The procedures described require both technical skill and experience and the post-operative therapy programmes must be carefully chosen for each patient. With the important laboratory and clinical advancements occurring in many areas of flexor tendon surgery, it is realistic to believe that in the future the techniques described here will be substantially altered and modified and to hope that results will continue to improve until the patient and surgeon can expect to restore most digits to nearly full function after flexor tendon interruption. PMID:2695588

  3. Cell phenotypic variation in normal and damaged tendons

    PubMed Central

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

    2007-01-01

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

  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. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:346-353, 2016. PMID:25640809

  5. Murine patellar tendon biomechanical properties and regional strain patterns during natural tendon-to-bone healing after acute injury

    PubMed Central

    Gilday, Steven D.; Casstevens, E. Chris; Kenter, Keith; Shearn, Jason T.; Butler, David L.

    2014-01-01

    Tendon-to-bone healing following acute injury is generally poor and often fails to restore normal tendon biomechanical properties. In recent years, the murine patellar tendon (PT) has become an important model system for studying tendon healing and repair due to its genetic tractability and accessible location within the knee. However, the mechanical properties of native murine PT, specifically the regional differences in tissue strains during loading, and the biomechanical outcomes of natural PT-to-bone healing have not been well characterized. Thus, in this study, we analyzed the global biomechanical properties and regional strain patterns of both normal and naturally healing murine PT at three time points (2, 5, and 8 weeks) following acute surgical rupture of the tibial enthesis. Normal murine PT exhibited distinct regional variations in tissue strain, with the insertion region experiencing approximately 2.5 times greater strain than the midsubstance at failure (10.80 ± 2.52% vs. 4.11 ± 1.40%; mean ± SEM). Injured tendons showed reduced structural (ultimate load and linear stiffness) and material (ultimate stress and linear modulus) properties compared to both normal and contralateral sham-operated tendons at all healing time points. Injured tendons also displayed increased local strain in the insertion region compared to contralateral shams at both physiologic and failure load levels. 93.3% of injured tendons failed at the tibial insertion, compared to only 60% and 66.7% of normal and sham tendons, respectively. These results indicate that 8 weeks of natural tendon-to-bone healing does not restore normal biomechanical function to the murine PT following injury. PMID:24210849

  6. 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

  7. 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. PMID:21735243

  8. Miscellaneous conditions of tendons, tendon sheaths, and ligaments.

    PubMed

    Dyson, S J; Dik, K J

    1995-08-01

    The use of diagnostic ultrasonography has greatly enhances our ability to diagnose injuries of tendons and tendon sheaths that were previously either unrecognized or poorly understood. For may of these injuries, there is currently only a small amount of follow-up data. This article considers injuries of the deep digital flexor tendon and its accessory ligament, the carpal tunnel syndrome soft tissue swellings on the dorsal aspect of the carpus, intertubercular (bicipital) bursitis and bicipital tendinitis, injuries of the gastrocnemius tendon, common calcaneal tendinitis, rupture of peroneus (fibularis tertius) and ligaments injuries of the back. PMID:7584739

  9. The Dynamics of Collagen Uncrimping and Lateral Contraction in Tendon and the Effect of Ionic Concentration

    PubMed Central

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

    2013-01-01

    Under tensile loading, tendon undergoes a number of unique structural changes that govern its mechanical response. For example, stretching a tendon is known to induce both the progressive “uncrimping” of wavy collagen fibrils and extensive lateral contraction mediated by fluid flow out of the tissue. However, it is not known whether these processes are interdependent. Moreover, the rate-dependence of collagen uncrimping and its contribution to tendon’s viscoelastic mechanical properties are unknown. Therefore, the objective of this study was to a) develop a methodology allowing for simultaneous measurement of crimp, stress, axial strain and lateral contraction in tendon under dynamic loading; b) determine the interdependence of collagen uncrimping and lateral contraction by testing tendons in different swelling conditions; and c) assess how the process of collagen uncrimping depends on loading rate. Murine flexor carpi ulnaris (FCU) tendons in varying ionic environments were dynamically stretched to a set strain level and imaged through a plane polariscope with the polarizer and analyzer at a fixed angle. Analysis of the resulting images allowed for direct measurement of the crimp frequency and indirect measurement of the tendon thickness. Our findings demonstrate that collagen uncrimping and lateral contraction can occur independently and interstitial fluid impacts tendon mechanics directly. Furthermore, tensile stress, transverse contraction and degree of collagen uncrimping were all rate-dependent, suggesting that collagen uncrimping plays a role in tendon’s dynamic mechanical response. This study is the first to characterize the time-dependence of collagen uncrimping in tendon establishes structure-function relationships for healthy tendons that can be used to better understand and assess changes in tendon mechanics after disease or injury. PMID:23876711

  10. [Questions concerning two-stage reconstruction of injured flexor tendons. III. Ultrastructure of the tenosynovium in the pseudo-tendon sheath created by using a silicone rod].

    PubMed

    Salamon, A; Bíró, V; Vámhidy, L; Trombitás, K; Józsa, L

    1993-01-01

    Authors have investigated the ultrastructure of the pseudo tendon sheath, formed with silicon rod and man. They have observed a superficial structure, resembling the normal tendon sheath in scanning electron microscopic examination. With transmission electron microscopy phagocyte "A" type and secretion "B" type synovial cells were found. Authors state that the newly formed tenosynovium has an important role in the nutrition of the tendon graft and the prevention of adhesions. PMID:8136879

  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. Distal biceps tendon injuries.

    PubMed

    Miyamoto, Ryan G; Elser, Florian; Millett, Peter J

    2010-09-01

    Distal biceps tendon ruptures present with an initial tearing sensation accompanied by acute pain; weakness may follow. The hook test is very reliable for diagnosing ruptures, and magnetic resonance imaging can provide information about the integrity and any intrasubstance degeneration of the tendon. There are subtle differences between the outcomes of single and modified two-incision operative repairs. With regard to complications, there is a higher prevalence of nerve injuries in association with single-incision techniques and a higher prevalence of heterotopic ossification in association with two-incision techniques. Fixation techniques include the use of bone tunnels, suture anchors, interference screws, and cortical fixation buttons. There is no clinical evidence supporting the use of one fixation method over another, although cortical button fixation has been shown to provide the highest load tolerance and stiffness. Postoperative rehabilitation has become more aggressive as fixation methods have improved. PMID:20810864

  13. Production of a sterilised decellularised tendon allograft for clinical use.

    PubMed

    Huang, Q; Ingham, E; Rooney, P; Kearney, J N

    2013-12-01

    Application of a high-level decontamination or sterilisation procedure and cell removal technique to tendon allograft can reduce the concerns of disease transmission, immune reaction, and may improve remodelling of the graft after implantation. The decellularised matrix can also be used as a matrix for tendon tissue engineering. One such sterilisation factor, Peracetic acid (PAA) has the advantage of not producing harmful reaction residues. The aim of this study was to evaluate the effects of PAA treatment and a cell removal procedure on the production of tendon matrix. Human patellar tendons, thawed from frozen were treated respectively as: Group 1, control with no treatment; Group 2, sterilised with PAA (0.1 % (w/v) PAA for 3 h) Group 3, decellularised (incubation successively in hypotonic buffer, 0.1 % (w/v) sodium dodecyl sulphate, and a nuclease solution); Group 4, decellularised and PAA sterilised. Histological analysis showed that no cells were visible after the decellularisation treatment. The integrity of tendon structure was maintained after decellularisation and PAA sterilisation, however, the collagen waveform was slightly loosened. No contact cytotoxicity was found in any of the groups. Determination of de-natured collagen showed no significant increase when compared with the control. This suggested that the decellularisation and sterilisation processing procedures did not compromise the major properties of the tendon. The sterilised, decellularised tendon could be suitable for clinical use. PMID:23443409

  14. On muscle, tendon and high heels.

    PubMed

    Csapo, R; Maganaris, C N; Seynnes, O R; Narici, M V

    2010-08-01

    Wearing high heels (HH) places the calf muscle-tendon unit (MTU) in a shortened position. As muscles and tendons are highly malleable tissues, chronic use of HH might induce structural and functional changes in the calf MTU. To test this hypothesis, 11 women regularly wearing HH and a control group of 9 women were recruited. Gastrocnemius medialis (GM) fascicle length, pennation angle and physiological cross-sectional area (PCSA), the Achilles' tendon (AT) length, cross-sectional area (CSA) and mechanical properties, and the plantarflexion torque-angle and torque-velocity relationships were assessed in both groups. Shorter GM fascicle lengths were observed in the HH group (49.6+/-5.7 mm vs 56.0+/-7.7 mm), resulting in greater tendon-to-fascicle length ratios. Also, because of greater AT CSA, AT stiffness was higher in the HH group (136.2+/-26.5 N mm(-1) vs 111.3+/-20.2 N mm(-1)). However, no differences in the GM PCSA to AT CSA ratio, torque-angle and torque-velocity relationships were found. We conclude that long-term use of high-heeled shoes induces shortening of the GM muscle fascicles and increases AT stiffness, reducing the ankle's active range of motion. Functionally, these two phenomena seem to counteract each other since no significant differences in static or dynamic torques were observed. PMID:20639419

  15. Wide-Awake Primary Flexor Tendon Repair, Tenolysis, and Tendon Transfer

    PubMed Central

    2015-01-01

    Tendon surgery is unique because it should ensure tendon gliding after surgery. Tendon surgery now can be performed under local anesthesia without tourniquet, by injecting epinephrine mixed with lidocaine, to achieve vasoconstriction in the area of surgery. This method allows the tendon to move actively during surgery to test tendon function intraoperatively and to ensure the tendon is properly repaired before leaving the operating table. I applied this method to primary flexor tendon repair in zone 1 or 2, tenolysis, and tendon transfer, and found this approach makes tendon surgery easier and more reliable. This article describes the method that I have used for tendon surgery. PMID:26330947

  16. Imaging horse tendons using multimodal 2-photon microscopy.

    PubMed

    Sivaguru, Mayandi; Eichorst, John Paul; Durgam, Sushmitha; Fried, Glenn A; Stewart, Allison A; Stewart, Matthew C

    2014-03-15

    Injuries and damage to tendons plague both human and equine athletes. At the site of injuries, various cells congregate to repair and re-structure the collagen. Treatments for collagen injury range from simple procedures such as icing and pharmaceutical treatments to more complex surgeries and the implantation of stem cells. Regardless of the treatment, the level of mechanical stimulation incurred by the recovering tendon is crucial. However, for a given tendon injury, it is not known precisely how much of a load should be applied for an effective recovery. Both too much and too little loading of the tendon could be detrimental during recovery. A mapping of the complex local environment imparted to any cell present at the site of a tendon injury may however, convey fundamental insights related to their decision making as a function of applied load. Therefore, fundamentally knowing how cells translate mechanical cues from their external environment into signals regulating their functions during repair is crucial to more effectively treat these types of injuries. In this paper, we studied systems of tendons with a variety of 2-photon-based imaging techniques to examine the local mechanical environment of cells in both normal and injured tendons. These tendons were chemically treated to instigate various extents of injury and in some cases, were injected with stem cells. The results related by each imaging technique distinguish with high contrast and resolution multiple morphologies of the cells' nuclei and the alignment of the collagen during injury. The incorporation of 2-photon FLIM into this study probed new features in the local environment of the nuclei that were not apparent with steady-state imaging. Overall, this paper focuses on horse tendon injury pattern and analysis with different 2-photon confocal modalities useful for wide variety of application in damaged tissues. PMID:23871762

  17. Repair of Achilles tendon defect with autologous ASCs engineered tendon in a rabbit model.

    PubMed

    Deng, Dan; Wang, Wenbo; Wang, Bin; Zhang, Peihua; Zhou, Guangdong; Zhang, Wen Jie; Cao, Yilin; Liu, Wei

    2014-10-01

    Adipose derived stem cells (ASCs) are an important cell source for tissue regeneration and have been demonstrated the potential of tenogenic differentiation in vitro. This study explored the feasibility of using ASCs for engineered tendon repair in vivo in a rabbit Achilles tendon model. Total 30 rabbits were involved in this study. A composite tendon scaffold composed of an inner part of polyglycolic acid (PGA) unwoven fibers and an outer part of a net knitted with PGA/PLA (polylactic acid) fibers was used to provide mechanical strength. Autologous ASCs were harvested from nuchal subcutaneous adipose tissues and in vitro expanded. The expanded ASCs were harvested and resuspended in culture medium and evenly seeded onto the scaffold in the experimental group, whereas cell-free scaffolds served as the control group. The constructs of both groups were cultured inside a bioreactor under dynamic stretch for 5 weeks. In each of 30 rabbits, a 2 cm defect was created on right side of Achilles tendon followed by the transplantation of a 3 cm cell-seeded scaffold in the experimental group of 15 rabbits, or by the transplantation of a 3 cm cell-free scaffold in the control group of 15 rabbits. Animals were sacrificed at 12, 21 and 45 weeks post-surgery for gross view, histology, and mechanical analysis. The results showed that short term in vitro culture enabled ASCs to produce matrix on the PGA fibers and the constructs showed tensile strength around 50 MPa in both groups (p > 0.05). With the increase of implantation time, cell-seeded constructs gradually form neo-tendon and became more mature at 45 weeks with histological structure similar to that of native tendon and with the presence of bipolar pattern and D-periodic structure of formed collagen fibrils. Additionally, both collagen fibril diameters and tensile strength increased continuously with significant difference among different time points (p < 0.05). In contrast, cell-free constructs failed to form good quality tendon tissue with fibril structure observable only at 45 weeks. There were significant differences in both collagen fibril diameter and tensile strength between two groups at all examined time points (p < 0.05). The results of this study support that ASCs are likely to be a potential cell source for in vivo tendon engineering and regeneration. PMID:25069604

  18. 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 bone formation near the tendon insertion. These conserved and time-varying aspects of interface composition may have important implications for the growth and mechanical stability of the tendon-to-bone attachment throughout development. PMID:23152788

  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 bone formation near the tendon insertion. These conserved and time-varying aspects of interface composition may have important implications for the growth and mechanical stability of the tendon-to-bone attachment throughout development. PMID:23152788

  20. 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. PMID:22708365

  1. Effects of various decellularization methods on histological and biomechanical properties of rabbit tendons

    PubMed Central

    XING, SHUXING; LIU, CONG; XU, BING; CHEN, JIANCHANG; YIN, DONGFENG; ZHANG, CHUNHAO

    2014-01-01

    The aim of the present study was to investigate the effects of various decellularization methods on the histological and biomechanical properties of rabbit tendons. In total, six chemical reagents, including 1% t-octyl-phenoxypolyethoxyethanol (Triton-X 100), 0.5% sodium dodecyl sulfate (SDS), 1% tri-n-butyl phosphate (TnBP), 1% Triton-X 100 + 0.5% SDS, 1% TnBP + 0.5% SDS and 1% TnBP + 1% Triton-X 100, were used on rabbit semitendinosus muscles and flexor digitorum tendons for 24 h to remove cells. Hematoxylin and eosin staining was applied for histological observation, while tension testing was used for biomechanical studies. The effects of the various decellularization methods on the histological structure and biomechanical properties of rabbit tendons were evaluated. A group of fresh tendons treated with phosphate-buffered saline served as controls. The various decellularization methods resulted in different effects on the tendons. All the treatment groups exhibited a decrease in tendon biomechanical properties, but no statistically significant differences were observed among the experimental groups. The extensibility of the 1% TnBP-treated group was found to be greater than that of the other groups; however, the difference was not statistically significant. Histologically, the 1% TnBP + 0.5% SDS treatment was shown to have the least impact on the rabbit tendon structure, with good decellularization and no clear cellular remnants observed. The 1% Triton-X 100 + 0.5% SDS treatment had a pronounced effect on the tendon collagen structure and a number of collagen ruptures were observed. Overall, 1% TnBP + 0.5% SDS was found to be the most effective compared with the other treatments, as this treatment preserved the tendon collagen structure while completely removing the cells. Tendons treated with 1% TnBP + 0.5% SDS were histologically similar to normal tendon tissue and biomechanically similar to the tendons in the control group. PMID:25009631

  2. 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

  3. Synthetic collagen fascicles for the regeneration of tendon tissue.

    PubMed

    Kew, S J; Gwynne, J H; Enea, D; Brookes, R; Rushton, N; Best, S M; Cameron, R E

    2012-10-01

    The structure of an ideal scaffold for tendon regeneration must be designed to provide a mechanical, structural and chemotactic microenvironment for native cellular activity to synthesize functional (i.e. load bearing) tissue. Collagen fibre scaffolds for this application have shown some promise to date, although the microstructural control required to mimic the native tendon environment has yet to be achieved allowing for minimal control of critical in vivo properties such as degradation rate and mass transport. In this report we describe the fabrication of a novel multi-fibre collagen fascicle structure, based on type-I collagen with failure stress of 25-49 MPa, approximating the strength and structure of native tendon tissue. We demonstrate a microscopic fabrication process based on the automated assembly of type-I collagen fibres with the ability to produce a controllable fascicle-like, structural motif allowing variable numbers of fibres per fascicle. We have confirmed that the resulting post-fabrication type-I collagen structure retains the essential phase behaviour, alignment and spectral characteristics of aligned native type-I collagen. We have also shown that both ovine tendon fibroblasts and human white blood cells in whole blood readily infiltrate the matrix on a macroscopic scale and that these cells adhere to the fibre surface after seven days in culture. The study has indicated that the synthetic collagen fascicle system may be a suitable biomaterial scaffold to provide a rationally designed implantable matrix material to mediate tendon repair and regeneration. PMID:22728568

  4. [Pathophysiology of overuse tendon injury].

    PubMed

    Kannus, P; Paavola, M; Paakkala, T; Parkkari, J; Järvinen, T; Järvinen, M

    2002-10-01

    Overuse tendon injury is one of the most common injuries in sports. The etiology as well as the pathophysiological mechanisms leading to tendinopathy are of crucial medical importance. At the moment intrinsic and extrinsic factors are assumed as mechanisms of overuse tendon injury. Except for the acute, extrinsic trauma, the chronic overuse tendon injury is a multifactorial process. There are many other factors, such as local hypoxia, less of nutrition, impaired metabolism and local inflammatory that may also contribute to the development of tissue damage. The exact interaction of these factors cannot be explained entirely at the moment. Further studies will be necessary in order to get more information. PMID:12402104

  5. Study of optical properties and proteoglycan content of tendons by polarization sensitive optical coherence tomography

    NASA Astrophysics Data System (ADS)

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

    2012-08-01

    The highly orientated collagen fibers in tendons play a critical role for transferring tensile stress, and they demonstrate birefringent optical properties. However, the influence that proteoglycans (PGs) have on the optical properties of tendons is yet to be fully elucidated. PGs are the essential components of the tendon extracellular matrix; the changes in their quantities and compositions have been associated with tendinopathies. In this study, polarization sensitive optical coherence tomography (PS-OCT) has been used to reveal the relationship between PG content/location and birefringence properties of tendons. Fresh chicken tendons were imaged at regular intervals by PS-OCT and polarization light microscopy during the extraction of PGs, using guanidine hydrochloride (GuHCl). Complementary time-lapsed images taken from the two modalities mutually demonstrated that the extraction of PGs disturbed the local organization of collagen bundles. This corresponded with a decrease in birefringence and associated banding pattern observed by PS-OCT. Furthermore, this study revealed there was a higher concentration of PGs in the outer sheath region than in the fascicles, and therefore the change in birefringence was reduced when extraction was performed on unsheathed tendons. The results provide new insights of tendon structure and the role of PGs on the structural stability of tendons, which also demonstrates the great potential for using PS-OCT as a diagnostic tool to examine tendon pathology.

  6. Collagen fiber re-alignment in a neonatal developmental mouse supraspinatus tendon model.

    PubMed

    Miller, Kristin S; Connizzo, Brianne K; Soslowsky, Louis J

    2012-05-01

    Collagen fiber re-alignment is one postulated mechanism of tendon structural response to load. While collagen fiber distribution has been shown to vary by tendon location in the supraspinatus tendon (SST), changes in local re-alignment behavior have not been examined throughout postnatal development. Postnatal tendons, with immature collagen fibrils, may respond to load in a much different manner than collagen fibers with mature fiber-fiber and fiber-matrix connections. Local collagen fiber re-alignment is quantified throughout tensile mechanical testing in a developmental mouse SST model and corresponding mechanical properties measured. Collagen fiber re-alignment occurred during preconditioning for 28 day old tendons, at the toe-region for 10 day tendons and at the linear-region for 4 day tendon midsubstance. Mechanical properties increased with developmental age. Linear modulus was lower at the insertion site compared to the midsubstance location at all time points. Local differences in collagen fiber distributions were found at 10 and 28 days for all mechanical testing points (except the 10 day transition point). This study found that collagen fiber re-alignment depends on developmental age and suggests that collagen fibrillogenesis may influence the tendon's ability to structurally respond to load. Additionally, results indicate that the insertion site and tendon midsubstance locations develop differently. PMID:22183194

  7. 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 rectus femoris tendon calcification yields satisfying results with few risks to the patient as well as rapid recovery. Clinical Relevance: The recent improvements in hip arthroscopy give the opportunity to address an increasing number of hip conditions effectively and safely, with rapid recovery for the patient. Arthroscopic excision of rectus femoris tendon calcification can be considered a feasible option, with few risks to the patient, rapid recovery, and satisfying outcomes. PMID:26535288

  8. Tendon, tendon sheath, and ligament injuries in the pastern.

    PubMed

    Dyson, S J; Denoix, J M

    1995-08-01

    The palmar (plantar) aspect of the pastern is an anatomically complex area and an understanding of this is a prerequisite for accurate diagnosis of injuries in this area. The gross and normal ultrasonographic anatomy are described, and injuries of the superficial and deep digital flexor tendons and the digital flexor tendon sheath, the distal sesamoidean ligaments, and the palmar ligaments of the proximal interphalangeal joint are discussed. PMID:7584735

  9. [Achilles tendon ruptures and tibialis anterior tendon ruptures].

    PubMed

    Pagenstert, G; Leumann, A; Frigg, A; Valderrabano, V

    2010-12-01

    Achilles tendon ruptures (ATR) are becoming the most frequent tendon rupture of the lower extremity, whereas less than 100 cases of tibialis anterior tendon ruptures (TATR) have been reported. Common in both tendons are the degenerative causes of ruptures in a susceptible tendon segment, whereas traumatic transections occur at each level. Triceps surae and tibialis anterior muscles are responsible for the main sagittal ankle range of motion and ruptures lead to a distinctive functional deficit. However, diagnosis is delayed in up to 25% of ATR and even more frequently in TATR. Early primary repair provides the best functional results. With progressive retraction and muscle atrophy delayed tendon reconstruction has less favourable functional results. But not all patients need full capacity, power and endurance of these muscles and non-surgical treatment should not be forgotten. Inactive patients with significant comorbidities and little disability should be informed that surgical treatment of TATR is complicated by high rates of rerupture and surgical treatment of ATR can result in wound healing problems rarely necessitating some kind of transplantation. PMID:21110002

  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. PMID:25694241

  11. Endoscopic Management of Gluteus Medius Tendon Tears.

    PubMed

    Thaunat, Mathieu; Noël, Eric; Nové-Josserand, Laurent; Murphy, Colin G; Sbiyaa, Mouhcine; Sonnery-Cottet, Bertrand

    2016-03-01

    Tears in the gluteus medius and minimus tendons have been recognized as an important cause of recalcitrant greater trochanteric pain syndrome. Because of the frequency of partial-thickness undersurface tears, this relatively unknown pathology is often misdiagnosed and left untreated. Surgery is indicated in case of 4 associated conditions: (i) Failure of conservative treatment with duration of symptoms >6 months; (ii) magnetic resonance imaging showing a tendon tear; (iii) positive ultrasound-guided infiltration test; and (iv) the absence of an evolved fatty degeneration or atrophy of the gluteus medius and minimus muscle. Endoscopic repair of partial or full-thickness tears, with systematic resection of the bony structures implicated in the impingement, and a complete bursectomy appear to give satisfactory results, although these results remain to be confirmed by clinical studies with longer follow-up. The degree of tendon degeneration may compromise the tissue left for reattachment, raising concerns over its healing capacity, durability, and ultimate strength of the repair. PMID:26752773

  12. Accuracy of MRI technique in measuring tendon cross-sectional area.

    PubMed

    Couppé, C; Svensson, R B; Sødring-Elbrønd, V; Hansen, P; Kjaer, M; Magnusson, S P

    2014-05-01

    Magnetic resonance imaging (MRI) has commonly been applied to determine tendon cross-sectional area (CSA) and length either to measure structural changes or to normalize mechanical measurements to stress and strain. The ability to reproduce CSA measurements on MRI images has been reported, but the accuracy in relation to actual tendon dimensions has never been investigated. The purpose of this study was to compare tendon CSA measured by MRI with that measured in vitro with the mould casting technique. The knee of a horse was MRI-scanned with 1.5 and 3 tesla, and two examiners measured the patellar tendon CSA. Thereafter, the patellar tendon of the horse was completely dissected and embedded in an alginate cast. The CSA of the embedded tendon was measured directly by optical imaging of the cast impression. 1.5 tesla grey tendon CSA and 3 tesla grey tendon CSA were 16.5% and 13.2% lower than the mould tendon CSA, respectively. Also, 3 tesla tendon CSA, based on the red-green border on the National Institute of Health (NIH) colour scale, was lower than the mould tendon CSA by 2.8%. The typical error between examiners was below 2% for all the measured CSA. The typical error between examiners was below 2% for all the measured CSA. These data show that measuring tendon CSA on the grey-scale MRI images is associated with an underestimation, but by optimizing the measurement using a 3 tesla MRI and the appropriate NIH colour scale, this underestimation could be reduced to 2.8% compared with the direct measurements on the mould. PMID:24119143

  13. 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

  14. Tendon proper- and peritenon-derived progenitor cells have unique tenogenic properties

    PubMed Central

    2014-01-01

    Introduction Multipotent progenitor populations exist within the tendon proper and peritenon of the Achilles tendon. Progenitor populations derived from the tendon proper and peritenon are enriched with distinct cell types that are distinguished by expression of markers of tendon and vascular or pericyte origins, respectively. The objective of this study was to discern the unique tenogenic properties of tendon proper- and peritenon-derived progenitors within an in vitro model. We hypothesized that progenitors from each region contribute differently to tendon formation; thus, when incorporated into a regenerative model, progenitors from each region will respond uniquely. Moreover, we hypothesized that cell populations like progenitors were capable of stimulating tenogenic differentiation, so we generated conditioned media from these cell types to analyze their stimulatory potentials. Methods Isolated progenitors were seeded within fibrinogen/thrombin gel-based constructs with or without supplementation with recombinant growth/differentiation factor-5 (GDF5). Early and late in culture, gene expression of differentiation markers and matrix assembly genes was analyzed. Tendon construct ultrastructure was also compared after 45 days. Moreover, conditioned media from tendon proper-derived progenitors, peritenon-derived progenitors, or tenocytes was applied to each of the three cell types to determine paracrine stimulatory effects of the factors secreted from each of the respective cell types. Results The cell orientation, extracellular domain and fibril organization of constructs were comparable to embryonic tendon. The tendon proper-derived progenitors produced a more tendon-like construct than the peritenon-derived progenitors. Seeded tendon proper-derived progenitors expressed greater levels of tenogenic markers and matrix assembly genes, relative to peritenon-derived progenitors. However, GDF5 supplementation improved expression of matrix assembly genes in peritenon progenitors and structurally led to increased mean fibril diameters. It also was found that peritenon-derived progenitors secrete factor(s) stimulatory to tenocytes and tendon proper progenitors. Conclusions Data demonstrate that, relative to peritenon-derived progenitors, tendon proper progenitors have greater potential for forming functional tendon-like tissue. Furthermore, factors secreted by peritenon-derived progenitors suggest a trophic role for this cell type as well. Thus, these findings highlight the synergistic potential of including these progenitor populations in restorative tendon engineering strategies. PMID:25005797

  15. Early stage fatigue damage occurs in bovine tendon fascicles in the absence of changes in mechanics at either the gross or micro-structural level

    PubMed Central

    Shepherd, Jennifer H.; Riley, Graham P.; Screen, Hazel R.C.

    2014-01-01

    Many tendon injuries are believed to result from repetitive motion or overuse, leading to the accumulation of micro-damage over time. In vitro fatigue loading can be used to characterise damage during repeated use and investigate how this may relate to the aetiology of tendinopathy. This study considered the effect of fatigue loading on fascicles from two functionally distinct bovine tendons: the digital extensor and deep digital flexor. Micro-scale extension mechanisms were investigated in fascicles before or after a period of cyclic creep loading, comparing two different measurement techniques – the displacement of a photo-bleached grid and the use of nuclei as fiducial markers. Whilst visual damage was clearly identified after only 300 cycles of creep loading, these visual changes did not affect either gross fascicle mechanics or fascicle microstructural extension mechanisms over the 900 fatigue cycles investigated. However, significantly greater fibre sliding was measured when observing grid deformation rather than the analysis of nuclei movement. Measurement of microstructural extension with both techniques was localised and this may explain the absence of change in microstructural deformation in response to fatigue loading. Alternatively, the data may demonstrate that fascicles can withstand a degree of matrix disruption with no impact on mechanics. Whilst use of a photo-bleached grid to directly measure the collagen is the best indicator of matrix deformation, nuclei tracking may provide a better measure of the strain perceived directly by the cells. PMID:25001495

  16. Early stage fatigue damage occurs in bovine tendon fascicles in the absence of changes in mechanics at either the gross or micro-structural level.

    PubMed

    Shepherd, Jennifer H; Riley, Graham P; Screen, Hazel R C

    2014-10-01

    Many tendon injuries are believed to result from repetitive motion or overuse, leading to the accumulation of micro-damage over time. In vitro fatigue loading can be used to characterise damage during repeated use and investigate how this may relate to the aetiology of tendinopathy. This study considered the effect of fatigue loading on fascicles from two functionally distinct bovine tendons: the digital extensor and deep digital flexor. Micro-scale extension mechanisms were investigated in fascicles before or after a period of cyclic creep loading, comparing two different measurement techniques - the displacement of a photo-bleached grid and the use of nuclei as fiducial markers. Whilst visual damage was clearly identified after only 300 cycles of creep loading, these visual changes did not affect either gross fascicle mechanics or fascicle microstructural extension mechanisms over the 900 fatigue cycles investigated. However, significantly greater fibre sliding was measured when observing grid deformation rather than the analysis of nuclei movement. Measurement of microstructural extension with both techniques was localised and this may explain the absence of change in microstructural deformation in response to fatigue loading. Alternatively, the data may demonstrate that fascicles can withstand a degree of matrix disruption with no impact on mechanics. Whilst use of a photo-bleached grid to directly measure the collagen is the best indicator of matrix deformation, nuclei tracking may provide a better measure of the strain perceived directly by the cells. PMID:25001495

  17. Prominent Actin Fiber Arrays in Drosophila Tendon Cells Represent Architectural Elements Different from Stress Fibers

    PubMed Central

    Alves-Silva, Juliana; Hahn, Ines; Huber, Olga; Mende, Michael; Reissaus, Andre

    2008-01-01

    Tendon cells are specialized cells of the insect epidermis that connect basally attached muscle tips to the cuticle on their apical surface via prominent arrays of microtubules. Tendon cells of Drosophila have become a useful genetic model system to address questions with relevance to cell and developmental biology. Here, we use light, confocal, and electron microscopy to present a refined model of the subcellular organization of tendon cells. We show that prominent arrays of F-actin exist in tendon cells that fully overlap with the microtubule arrays, and that type II myosin accumulates in the same area. The F-actin arrays in tendon cells seem to represent a new kind of actin structure, clearly distinct from stress fibers. They are highly resistant to F-actin–destabilizing drugs, to the application of myosin blockers, and to loss of integrin, Rho1, or mechanical force. They seem to represent an important architectural element of tendon cells, because they maintain a connection between apical and basal surfaces even when microtubule arrays of tendon cells are dysfunctional. Features reported here and elsewhere for tendon cells are reminiscent of the structural and molecular features of support cells in the inner ear of vertebrates, and they might have potential translational value. PMID:18667532

  18. Partial rupture of the distal biceps tendon.

    PubMed

    Dürr, H R; Stäbler, A; Pfahler, M; Matzko, M; Refior, H J

    2000-05-01

    Partial rupture of the distal biceps tendon is a relatively rare event, and various degrees of partial tendon tears have been reported. In the current study four patients with partial atraumatic distal biceps tendon tears (mean age, 59 years; range, 40-82 years) are reported. In all four patients, a common clinical pattern emerged. Pain at the insertion of the distal biceps tendon in the radius unrelated to any traumatic event was the main symptom. In all patients the diagnosis was based on magnetic resonance imaging or computed tomography imaging. In three of four patients the partial rupture of the tendon caused a significant bursalike lesion. The typical appearance was a partially ruptured biceps tendon, with contrast enhancement signaling the degree of degeneration, tenosynovitis, and soft tissue swelling extending along the tendon semicircular to the proximal radius. In three patients, conservative treatment was successful. Only one patient needed surgery, with reinsertion of the tendon resulting in total functional recovery. PMID:10818980

  19. 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

  20. Arthroscopic biceps tendon tenodesis: the anchorage technical note.

    PubMed

    Castagna, A; Conti, M; Mouhsine, E; Bungaro, P; Garofalo, R

    2006-06-01

    Treatment of long head biceps (LHB) tendon pathology has become an area of renewed interest and debate among orthopaedic surgeons in recent years. The background of this manuscript is a description of biceps tenodesis which ensure continual dynamic action of the tendon which depresses the head and impedes lateral translation. A new technique has been developed in order to treat LHB tendon irreversible structural abnormalities associated with cuff rotator lesions. This technique entails the construction of a biological anchor between the LHB and supraspinatus and/or infraspinatus tendons according to arthroscopic findings. The rationale, although not supported by biomechanical studies is to obtain a triple, biomechanical effect. The first of these biomechanical effects which we try to promote through the procedure of transposition is the elimination of the deviation and oblique angle which occurs as the LHB completes its intra-articular course prior to reaching the bicipital groove. Furthermore, we have found this technique extremely useful in the presence of large ruptures of the rotator cuff with muscle retraction. The most common complication associated to this particular method, observed in less than 3%, is failed biological fixation which manifests as subsidence of the tenodesis and consequent descent of the tendon with evident aesthetic deformity. PMID:16374589

  1. Staged tendon grafts and soft tissue coverage

    PubMed Central

    Elliot, David

    2011-01-01

    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. PMID:22022043

  2. 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.

  3. A New Method for Modeling Spatial Prestressing Tendons

    NASA Astrophysics Data System (ADS)

    Li, Yi; Wang, Yuqian; Liu, Gao

    2010-05-01

    As a standard simulation procedure for curved lines and curved surfaces, spline has been widely used in the domain of computer-aided design. This paper presents a simple but relatively accurate procedure for the description of prestressing tendons. Cubic splines instead of conventional parabolic ones are introduced to obtain the characteristic parameters of the curved tendon profiles. The direct internal load method is adopted to obtain the equivalent load and loss of tendon force. In comparison with the traditional methods, Cubic splines needs less parameter for pre-processor and leads to higher accuracy in calculation. The direct internal load method can demonstrate the regularity of prestressing force acting on the structure, which modifies the prevalent equivalent load method. The results of the analysis presented in this paper indicate that the proposed method turns out to be convenient and reasonably accurate in the analysis of prestressed concrete bridges.

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

    PubMed

    Subramanian, Arul; Schilling, Thomas F

    2015-12-15

    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

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

    PubMed Central

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

    2013-01-01

    Tendon consists of highly ordered type I collagen molecules that are grouped together to form subunits of increasing diameter. At each hierarchical level, the type I collagen is interspersed with a predominantly non-collagenous matrix (NCM) (Connect. Tissue Res., 6, 1978, 11). Whilst many studies have investigated the structure, organization and function of the collagenous matrix within tendon, relatively few have studied the non-collagenous components. However, there is a growing body of research suggesting the NCM plays an important role within tendon; adaptations to this matrix may confer the specific properties required by tendons with different functions. Furthermore, age-related alterations to non-collagenous proteins have been identified, which may affect tendon resistance to injury. This review focuses on the NCM within the tensional region of developing and mature tendon, discussing the current knowledge and identifying areas that require further study to fully understand structure–function relationships within tendon. This information will aid in the development of appropriate techniques for tendon injury prevention and treatment. PMID:23718692

  6. Purified collagen I oriented membrane for tendon repair: an ex vivo morphological study.

    PubMed

    Gigante, Antonio; Busilacchi, Alberto; Lonzi, Barbara; Cecconi, Stefano; Manzotti, Sandra; Renghini, Chiara; Giuliani, Alessandra; Mattioli-Belmonte, Monica

    2013-05-01

    Injured tendons have limited repair ability after full-thickness lesions. Tendon regeneration properties and adverse reactions were assessed ex vivo in an experimental animal model using a new collagen I membrane. The multilamellar membrane obtained from purified equine Achilles tendon is characterized by oriented collagen I fibers and has been shown to sustain cell growth and orientation in vitro. The central third of the patellar tendon (PT) of 10 New Zealand White rabbits was sectioned and grafted with the collagen membrane; the contralateral PT was cut longitudinally (sham-operated controls). Animals were euthanized 1 or 6 months after surgery, and tendons were subjected to histological and Synchrotron Radiation-based Computed Microtomography (SRµCT) examination and 3D structure analysis. Histological and SRµCT findings showed satisfactory graft integration with native tendon. Histological examination also showed ongoing angiogenesis. Adverse side-effects (inflammation, rejection, calcification) were not observed. The multilamellar collagen I membrane can be considered as an effective tool for tendon defect repair and tendon augmentation. PMID:23335065

  7. 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

  8. Tibialis Anterior Tendon Transfer for Posterior Tibial Tendon Insufficiency.

    PubMed

    Ramanujam, Crystal L; Stapleton, John J; Zgonis, Thomas

    2016-01-01

    The Cobb procedure is useful for addressing stage 2 posterior tibial tendon dysfunction and is often accompanied by a medial displacement calcaneal osteotomy and/or lateral column lengthening. The Cobb procedure can also be combined with selected medial column arthrodesis and realignment osteotomies along with equinus correction when indicated. PMID:26590721

  9. In Situ Fibril Stretch and Sliding is Location-Dependent in Mouse Supraspinatus Tendons

    PubMed Central

    Connizzo, Brianne K.; Sarver, Joseph J.; Han, Lin; Soslowsky, Louis J.

    2014-01-01

    Tendons are able to transmit high loads efficiently due to their finely optimized hierarchical collagen structure. Two mechanisms by which tendons respond to load are collagen fibril sliding and deformation (stretch). While many studies have demonstrated that regional variations in tendon structure, composition, and organization contribute to the full tendon’s mechanical response, the location-dependent response to loading at the fibril level has not been investigated. In addition, the instantaneous response of fibrils to loading, which is clinically relevant for repetitive stretch or fatigue injuries, has also not been studied. Therefore, the purpose of this study was to quantify the instantaneous response of collagen fibrils throughout a mechanical loading protocol, both in the insertion site and in the midsubstance of the mouse supraspinatus tendon. Utilizing a novel atomic force microscopy-based imaging technique, tendons at various strain levels were directly visualized and analyzed for changes in fibril d-period with increasing tendon strain. At the insertion site, d-period significantly increased from 0% to 1% tendon strain, increased again from 3% to 5% strain, and decreased after 5% strain. At the midsubstance, d-period increased from 0% to 1% strain and then decreased after 7% strain. In addition, fibril d-period heterogeneity (fibril sliding) was present, primarily at 3% strain with a large majority occurring in the tendon midsubstance. This study builds upon previous work by adding information on the instantaneous and regional-dependent fibrillar response to mechanical loading and presents data proposing that collagen fibril sliding and stretch are directly related to tissue organization and function. PMID:25468300

  10. Hamstring tendon harvesting--Effect of harvester on tendon characteristics and soft tissue disruption; cadaver study.

    PubMed

    Charalambous, C P; Alvi, F; Phaltankar, P; Gagey, O

    2009-06-01

    The purpose of this study was to determine whether the type of hamstring tendon harvester used can influence harvested tendon characteristics and soft tissue disruption. We compared two different types of tendon harvesters with regard to the length of tendon obtained and soft tissue disruption during hamstring tendon harvesting. Thirty six semitendinosus and gracilis tendons were harvested using either a closed stripper or a blade harvester in 18 paired knees from nine human fresh cadavers. Use of the blade harvester gave longer lengths of usable tendon whilst minimising the stripping of muscle and of any non-usable tendon. Our results suggest that the type of harvester per se can influence the length of tendon harvested as well as soft tissue disruption. Requesting such data from the industry prior to deciding which harvester to use seems desirable. PMID:19272780

  11. 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

  12. Minimally invasive quadriceps tendon harvest.

    PubMed

    Almazán Díaz, Arturo; Cruz López, Francisco; Pérez Jiménez, Francisco-Xavier; Ibarra Ponce de León, José-Clemente

    2006-06-01

    Quadriceps tendon (QT) is becoming a popular graft for primary and revision ligament surgery. A subcutaneous technique for graft harvesting a QT is presented. Special closed tendon strippers were designed; these devices have 10- and 11-mm inner diameters and are stronger and sharper than regular hamstrings strippers. In the mid-line of the patellar upper pole, a 2-cm longitudinal incision is made, a 20- x 10-mm bone plug is created with an oscillating saw, and the tendon stripper is positioned and advanced into the thigh, dissecting the QT until the desired length, usually 10 cm, is obtained. The graft can be released by making a stab incision at the device's tip or by ventrally pointing and turning the tendon stripper to amputate the graft's end. The QT graft can be prepared in several fashions for 1- or 2-bundle ligament reconstructions. The technique was tested and refined in 3 cadaver specimens and has been used at our institution since 2003 in 18 primary posterior cruciate ligament reconstructions with no problems. This minimally invasive technique is safe, provides a consistently good-quality graft with excellent cosmetic results, and is simple and easily reproducible. PMID:16762711

  13. Posterior Tibial Tendon Dysfunction (PTTD)

    MedlinePLUS

    ... ACFAS | Información en Español Advanced Search Home » Foot & Ankle Conditions » Posterior Tibial Tendon Dysfunction (PTTD) Text Size ... the arch, and an inward rolling of the ankle. As the condition progresses, the symptoms will change. ...

  14. 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. PMID:25166893

  15. 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) would improve the estimation. Next, UEI was performed on five human cadaver feet mounted in a materials testing system (MTS) while the PTT was attached to a force actuator. A portable ultrasound scanner collected 2D 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+/-0.16GPa) using UEI. This was consistent with simultaneous measurements made by the MTS across the whole tendon (0.52+/-0.18GPa). 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 human PTT. Finally, we built a custom ankle inversion platform for in vivo imaging of human subjects (eight healthy volunteers and nine advanced PTTD patients). We found non-linear elastic properties of the PTTD, which could be quantified by the slope between the elastic modulus (E) and the inversion force (F). This slope (DeltaE/DeltaF), or Non-linear Elasticity Parameter (NEP), was significantly different for the two groups: 0.16+/-0.20 MPa/N for healthy tendons and 0.45+/-0.43 MPa/N for PTTD tendons. A receiver operating characteristic (ROC) curve revealed an area under the curve (AUC) of 0.83+/-0.07, which indicated that the classifier system is valid. In summary, the acoustic modeling, cadaveric studies, and in vivo experiments together demonstrated that UEI accurately quantifies tendon mechanical properties. As a valuable clinical tool, UEI also has the potential to help guide treatment decisions for advanced PTTD and other tendinopathies.

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

    NASA Astrophysics Data System (ADS)

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

    2011-03-01

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

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

    PubMed Central

    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

    2016-01-01

    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. PMID:26972579

  18. Generation of tendon-to-bone interface "enthesis" with use of recombinant BMP-2 in a rabbit model.

    PubMed

    Hashimoto, Yusuke; Yoshida, Gen; Toyoda, Hiromitsu; Takaoka, Kunio

    2007-11-01

    The anatomical structure at bone-tendon and bone-ligament interfaces is called the enthesis. Histologically, the enthesis is characterized by a transitional series of tissue layers from the end of the tendon to bone, including tendon, fibrocartilage, calcified fibrocartilage, and bone. This arrangement yields stronger direct connection of the soft tissues to bone. In surgical repair, the enthesis has proven difficult to reproduce, and the success of ligament-bone bonding has depended on the fibrous attachment that forms after any ligament reconstructions. In this study, we attempted to generate a direct-insertion enthesis in two stages. First, recombinant human bone morphogenetic protein-2 (rhBMP-2) was injected into the flexor digitorum communis tendon in the rabbit hind limb to induce ectopic ossicle formation. In a second step, the resultant tendon/ossicle complex was then surgically transferred onto the surface of the rabbit tibia to generate a stable tendon-bone junction. One month following surgery, histomorphological examination confirmed direct insertion of tendon-bone structures in the proximal tibia of the rabbit. Ultimate failure loads of the BMP-2-generated tendon-bone junction were significantly higher than in the control group (p < 0.01). These findings suggest that it is possible to successfully regenerate a direct tendon-to-bone enthesis. Use of this approach may enable successful reconstruction of joints rendered unstable after ligamentous rupture or laxity after anterior cruciate ligament injury. PMID:17557323

  19. Computed Tomographic Tenography of Normal Equine Digital Flexor Tendon Sheath: An Ex Vivo Study

    PubMed Central

    Lacitignola, Luca; De Luca, Pasquale; Guarracino, Alessandro; Crovace, Antonio

    2015-01-01

    Aim of this study was to document the normal computed tomographic tenography findings of digital flexor tendon sheath. Six ex vivo normal equine forelimbs were used. An axial approach was used to inject 185?mg/mL of iopamidol in a total volume of 60?mL into the digital flexor tendon sheaths. Single-slice helical scans, with 5?mm thickness, spaced every 3?mm, for a pitch of 0.6, and with bone algorithm reconstruction, were performed before and after injections of contrast medium. To obtain better image quality for multiplanar reconstruction and 3D reformatting, postprocessing retroreconstruction was performed to reduce the images to submillimetre thickness. Computed tomographic tenography of digital flexor tendon sheaths could visualize the following main tendon structures for every forelimb in contrast-enhanced images as low densities surrounded by high densities: superficial digital flexor tendon, deep digital flexor tendon, manica flexoria, mesotendons, and synovial recess. Results of this study suggest that computed tomographic tenography can be used with accuracy and sensitivity to evaluate the common disorders of the equine digital flexor tendon sheath and the intrathecal structures. PMID:26185709

  20. Synergy of tendon stem cells and platelet-rich plasma in tendon healing.

    PubMed

    Chen, Lei; Dong, Shi-Wu; Liu, Jun-Peng; Tao, Xu; Tang, Kang-Lai; Xu, Jian-Zhong

    2012-06-01

    Injured rat Achilles tendons were treated with botulism toxin to create a mechanically unloaded condition (unloaded) or left untreated (loaded), and then treated with phosphate-buffered saline (PBS), platelet-rich plasma (PRP), tendon stem cells (TSCs), or a combination (TSCs + PRP). mRNA and protein expression of collagen I, collagen III, tenascin C, and Smad 8 were determined by real time PCR and immunostaining, respectively. Loaded tendons treated with PBS, PRP, or TSCs for 3 or 14 days had higher collagen I mRNA expression than unloaded tendons. Loaded tendons treated with PBS for 3 or 14 days or with PRP for 3 days had higher collagen I protein levels than unloaded tendons. Loaded tendons treated for 3 days with PBS, for 14 days with PRP or TSCs or TSCs + PRP for 3 or 14 days had higher collagen III protein levels than unloaded tendons. Collagen I mRNA levels were higher in TSCs + PRP-treated loaded tendons compared to PBS-treated loaded tendons on day 3 of treatment. Based on changes in the expression of tendon-healing genes, our data suggest that the combination of TSCs and PRP has synergistic effects on tendon healing under both loaded and unloaded conditions, and loaded conditions improve tendon healing. PMID:22161871

  1. 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

  2. Influence of 90-day simulated microgravity on human tendon mechanical properties and the effect of resistive countermeasures.

    PubMed

    Reeves, N D; Maganaris, C N; Ferretti, G; Narici, M V

    2005-06-01

    While microgravity exposure is known to cause deterioration of skeletal muscle performance, little is known regarding its effect on tendon structure and function. Hence, the aims of this study were to investigate the effects of simulated microgravity on the mechanical properties of human tendon and to assess the effectiveness of resistive countermeasures in preventing any detrimental effects. Eighteen men (aged 25-45 yr) underwent 90 days of bed rest: nine performed resistive exercise during this period (BREx group), and nine underwent bed rest only (BR group). Calf-raise and leg-press exercises were performed every third day using a gravity-independent flywheel device. Isometric plantar flexion contractions were performed by using a custom-built dynamometer, and ultrasound imaging was used to determine the tensile deformation of the gastrocnemius tendon during contraction. In the BR group, tendon stiffness estimated from the gradient of the tendon force-deformation relation decreased by 58% (preintervention: 124 +/- 67 N/mm; postintervention: 52 +/- 28 N/mm; P < 0.01), and the tendon Young's modulus decreased by 57% postintervention (P < 0.01). In the BREx group, tendon stiffness decreased by 37% (preintervention: 136 +/- 66 N/mm; postintervention: 86 +/- 47 N/mm; P < 0.01), and the tendon Young's modulus decreased by 38% postintervention (P < 0.01). The relative decline in tendon stiffness and Young's modulus was significantly (P < 0.01) greater in the BR group compared with the BREx group. Unloading decreased gastrocnemius tendon stiffness due to a change in tendon material properties, and, although the exercise countermeasures did attenuate these effects, they did not completely prevent them. It is suggested that the total loading volume was not sufficient to completely prevent alterations in tendon mechanical properties. PMID:15705722

  3. Active Achilles tendon kinesitherapy accelerates Achilles tendon repair by promoting neurite regeneration?

    PubMed Central

    Jielile, Jiasharete; Aibai, Minawa; Sabirhazi, Gulnur; Shawutali, Nuerai; Tangkejie, Wulanbai; Badelhan, Aynaz; Nuerduola, Yeermike; Satewalede, Turde; Buranbai, Darehan; Hunapia, Beicen; Jialihasi, Ayidaer; Bai, Jingping; Kizaibek, Murat

    2012-01-01

    Active Achilles tendon kinesitherapy facilitates the functional recovery of a ruptured Achilles tendon. However, protein expression during the healing process remains a controversial issue. New Zealand rabbits, aged 14 weeks, underwent tenotomy followed immediately by Achilles tendon microsurgery to repair the Achilles tendon rupture. The tendon was then immobilized or subjected to postoperative early motion treatment (kinesitherapy). Mass spectrography results showed that after 14 days of motion treatment, 18 protein spots were differentially expressed, among which, 12 were up-regulated, consisting of gelsolin isoform b and neurite growth-related protein collapsing response mediator protein 2. Western blot analysis showed that gelsolin isoform b was up-regulated at days 7–21 of motion treatment. These findings suggest that active Achilles tendon kinesitherapy promotes the neurite regeneration of a ruptured Achilles tendon and gelsolin isoform b can be used as a biomarker for Achilles tendon healing after kinesitherapy. PMID:25317130

  4. Achilles tendon moment arms: the importance of measuring at constant tendon load when using the tendon excursion method.

    PubMed

    Olszewski, Katarzyna; Dick, Taylor J M; Wakeling, James M

    2015-04-13

    Achilles tendon moment arms are commonly measured using the tendon-excursion technique and ultrasound imaging of the muscle-tendon junction. The tendon-excursion technique relies on the assumption that the tendon load is constant and thus it does not stretch. However, previous studies have not enforced this constraint and thus it is not known how sensitive the estimated Achilles tendon moment arms are to varying load during the measurement process. The aim of this study was to compare estimates of Achilles tendon moment arms when calculated using the different constraints of constant force (and thus tendon stretch), constant joint torque, or contraction effort. Achilles tendon moment arms were measured for the medial and lateral gastrocnemii in 8 healthy male subjects across five different ankle angles (-5° dorsiflexion to 35° plantarflexion), and a range of contraction levels. Moment arms were calculated for three different constraints of constant force, torque, or effort. Moment arms were significantly greater for the lateral gastrocnemius than for the medial gastrocnemius. At low contraction levels, including the passive condition, the moment arms increased with plantarflexion, whereas the moment arms decreased with plantarflexion at higher contraction levels. There was no difference between the calculated moment arms using the constant force and the constant torque methods; however both these methods yielded significantly different moment arms when compared to the commonly used constant effort method. PMID:25700609

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

    PubMed Central

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

    2015-01-01

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

  6. Mesenchymal stem cell-dependent formation of heterotopic tendon-bone insertions (osteotendinous junctions).

    PubMed

    Shahab-Osterloh, Sandra; Witte, Frank; Hoffmann, Andrea; Winkel, Andreas; Laggies, Sandra; Neumann, Berit; Seiffart, Virginia; Lindenmaier, Werner; Gruber, Achim D; Ringe, Jochen; Häupl, Thomas; Thorey, Fritz; Willbold, Elmar; Corbeau, Pierre; Gross, Gerhard

    2010-09-01

    Ligament-to-bone and tendon-to-bone interfaces (entheses, osteotendinous junctions [OTJs]) serve to dissipate stress between soft tissue and bone. Surgical reconstruction of these interfaces is an issue of considerable importance as they are prone to injury and the integration of bone and tendon/ligament is in general not satisfactory. We report here the stem cell-dependent spontaneous formation of fibrocartilaginous and fibrous entheses in heterotopic locations of the mouse if progenitors possess a tenogenic and osteo-/chondrogenic capacity. This study followed the hypothesis that enhanced Bone Morphogenetic Protein (BMP)-signaling in adult mesenchymal stem cells that are induced for tendon formation may overcome the tendon-inherent interference with bone formation and may thus allow the stem cell-dependent formation of tendon-bone interfaces. The tenogenic and osteo-/chondrogenic competence was mediated by the adeno- and/or lentiviral expression of the biologically active Smad8 signaling mediator (Smad8ca) and of Bone Morphogenetic Protein 2 (BMP2). Modified mesenchymal progenitors were implanted in subcutaneous or intramuscular sites of the mouse. The stem cell-dependent enthesis formation was characterized histologically by immunohistological approaches and by in situ hybridization. Transplantation of modified murine stem cells resulted in the formation of tendinous and osseous structures exhibiting fibrocartilage-type OTJs, while, in contrast, the viral modification of primary human bone marrow-derived mesenchymal stromal/stem cells showed evidence of fibrous tendon-bone interface formation. Moreover, it could be demonstrated that Smad8ca expression alone was sufficient for the formation of tendon/ligament-like structures. These findings may contribute to the establishment of stem cell-dependent regenerative therapies involving tendon/ligaments and to the improvement of the insertion of tendon grafts at bony attachment sites, eventually. PMID:20882636

  7. Nutrient pathways of flexor tendons in primates

    SciTech Connect

    Manske, P.R.; Lesker, P.A.

    1982-09-01

    The perfusion and diffusion pathways to the flexor profundus tendons of 40 monkeys were investigated by measuring the uptake of tritiated proline by various tendon segments. In the absence of all vascular connections, the process of diffusion provides nutrients to all areas of flexor tendon and in this study the process of diffusion was greater. The distal segment of tendon was observed to be profused most rapidly. The proximal tendon segment is perfused from both the muscular-tendinous junction and the vinculum longus; vincular segment perfusion is via the vinculum longus vessels alone; central segment perfusion is shared by the vinculum longus and vinculum brevis vasculature. The distal segment uptake is by both the process of diffusion or vinculum brevis perfusion. The osseous attachment at the distal phalanx contributes little to tendon nutrition.

  8. Muscle Force and Power Following Tendon Repair at Altered Tendon Length

    PubMed Central

    Krochmal, Daniel J.; Kuzon, William M.; Urbanchek, Melanie G.

    2008-01-01

    Background While a great deal is known regarding the performance of muscle with intact tendon, little is known about muscle performance when tendon is surgically lengthened or shortened. This knowledge may allow surgeons to more accurately predict functional outcome following tendon repair when correcting a simple tendon laceration or performing a more complex vascularized neuromuscular transfer. Materials and Methods We studied muscle performance 12 weeks following extensor tendon repairs producing altered tendon lengths. Forty male Fischer 344 rats underwent division of the proximal and distal tendons of the extensor digitorum longus muscle. Tendons were immediately repaired producing tendons with increased length, decreased length, or pre-surgical length (control). Observation confirmed that altered tendon length produced inverse changes in initial resting muscle tension. Results Muscle in the Decreased Tendon Length group demonstrated a 15.2% greater muscle mass, 4.9% greater muscle length, 9.6% greater physiologic cross-sectional area, 12.6% greater maximum isometric force, and 31.9% greater maximum power relative to the Control Tendon Length group (p < 0.05). The Increased Tendon Length group did not differ significantly from the Control Tendon Length group for any measurement. Histologically, muscles set with a decreased tendon length demonstrated normal appearing hypertrophied fibers, without evidence of detrimental histological effects such as fibrosis, denervation, necrosis, inflammation, fiber type changes, or fiber splitting. Conclusion These data support the clinical practice of setting muscles with increased passive tension when performing tendon transfer surgeries. Conversely, setting muscles with decreased tension does not necessarily result in a force or power deficit. PMID:17961595

  9. The Effects of Irreversible Electroporation on the Achilles Tendon: An Experimental Study in a Rabbit Model

    PubMed Central

    Yan, Mingwei; Ding, Weidong; Xu, Kui; Fan, Qingyu; Li, Zhao

    2015-01-01

    Background To evaluate the potential effects of irreversible electroporation ablation on the Achilles tendon in a rabbit model and to compare the histopathological and biomechanical changes between specimens following electroporation ablation and radiofrequency ablation. Methods A total of 140 six-month-old male New Zealand rabbits were used. The animals were randomly divided into two groups, 70 in the radiofrequency ablation group and 70 in the electroporation group. In situ ablations were applied directly to the Achilles tendons of rabbits using typical electroporation (1800 V/cm, 90 pulses) and radiofrequency ablation (power control mode) protocols. Histopathological and biomechanical evaluations were performed to examine the effects of electroporation ablation and radiofrequency ablation over time. Results Both electroporation and radiofrequency ablation produced complete cell ablation in the target region. Thermal damage resulted in tendon rupture 3 days post radiofrequency ablation. In contrast, electroporation-ablated Achilles tendons preserved their biomechanical properties and showed no detectable rupture at this time point. The electroporation-ablated tendons exhibited signs of recovery, including tenoblast regeneration and angiogenesis within 2 weeks, and the restoration of their integral structure was evident within 12 weeks. Conclusions When applying electroporation to ablate solid tumors, major advantage could be that collateral damage to adjacent tendons or ligaments is minimized due to the unique ability of electroporation ablation to target the cell membrane. This advantage could have a significant impact on the field of tumor ablation near vital tendons or ligaments. PMID:26114962

  10. 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.

  11. Achilles tendon rupture in badminton.

    PubMed Central

    Kaalund, S; Lass, P; Høgsaa, B; Nøhr, M

    1989-01-01

    The typical badminton player with an Achilles tendon rupture is 36 years old and, despite limbering up, is injured at the rear line in a sudden forward movement. He resumes work within three months and has a slight lack of dorsiflexion in the ankle as the main complication. Most patients resume badminton within one year, but some finish their sports career, mainly due to fear of a new injury. The investigation discusses predisposing factors and prophylactic measures. PMID:2605439

  12. Fracture of an ossified tibialis anterior tendon.

    PubMed

    Lee, Woo-Chun; Moon, Jeong-Seok; Kim, Ji-Yeong; Ko, Hyeong-Tak

    2009-02-01

    Fractures of ossified tibialis anterior tendon have been successfully managed by the excision of the ossified tendon and transfer of the extensor hallucis longus tendon. A 64-year-old man sustained an injury during mountain hiking 2 weeks prior to presentation, falling down on his heels with his ankle fully plantarflexed. Two tender and bony hard masses were palpable along the course of the tibialis anterior tendon, one at the anteromedial aspect of the ankle and another at the dorsum of the talonavicular joint. Radiographs of the ankle demonstrated an approximately 2x1-cm ovoid-shaped bony mass at the anterior aspect of the ankle joint and another bony mass of similar size and shape at the dorsal aspect of the talonavicular joint. He underwent operative exploration, and complete rupture of the tendon through a bony mass was observed. The gap between the torn ends of the tendon after excision of the mass was too long to be repaired directly. Extensor hallucis longus tendon was retrieved 1 cm proximal to the metatarsophalangeal joint and was passed through the insertion of the anterior tibial tendon and pulled proximally and sutured to itself with the ankle in neutral. At 1 year after surgery, plain radiographs and ultrasonography showed no recurrence of calcification or ossification in the tendon and good mobility of the tibialis anterior muscle was observed. PMID:19301787

  13. Histopathological findings in spontaneous tendon ruptures.

    PubMed

    Józsa, L; Kannus, P

    1997-04-01

    A spontaneous rupture of a tendon may be defined as a rupture that occurs during movement and activity, that should not and usually does not damage the involved musculotendinous units (1). Spontaneous tendon ruptures were uncommon before the 1950s. Böhler found only 25 Achilles tendon ruptures in Wien between 1925 and 1948 (2). Mösender & Klatnek treated 20 Achilles tendon ruptures between 1953 and 1956, but 105 ruptures between 1964 and 1967 (3). Lawrence et al. found only 31 Achilles tendon ruptures in Boston during a period of 55 years (1900-1954) (4). During the recent decades tendon ruptures have, however, become relatively common in developed countries, especially in Europe and North America. A high incidence of tendon ruptures has been reported in Austria, Denmark, Finland, Germany. Hungary, Sweden, Switzerland and the USA; somewhat lower incidences have been reported in Canada, France, Great Britain and Spain. On the other hand, Greece, Japan, the Netherlands and Portugal have reported a clearly lower incidence. Interestingly, Achilles tendon ruptures are a rarity in developing countries, especially in Africa and East-Asia (5). In many developed countries, the increases in the rupture incidence have been dramatic. In the National Institute of Traumatology in Budapest, Hungary, the number of patients with an Achilles tendon rupture increased 285% in men and 500% in women between two successive 7-year periods, 1972-1978 and 1979-1985 (5). PMID:9211612

  14. Tendon sheath fibroma in the thigh.

    PubMed

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

    2012-04-01

    Tendon sheath fibromas are rare, benign soft tissue tumors that are predominantly found in the fingers, hands, and wrists of young adult men. This article describes a tendon sheath fibroma that developed in the thigh of a 70-year-old man, the only known tendon sheath fibroma to form in this location. Similar to tendon sheath fibromas that develop elsewhere, our patient's lesion presented as a painless, slow-growing soft tissue nodule. Physical examination revealed a firm, nontender mass with no other associated signs or symptoms. Although the imaging appearance of tendon sheath fibromas varies, our patient's lesion appeared dark on T1- and bright on T2-weighted magnetic resonance imaging. It was well marginated and enhanced with contrast.Histologically, tendon sheath fibromas are composed of dense fibrocollagenous stromas with scattered spindle-shaped fibroblasts and narrow slit-like vascular spaces. Most tendon sheath fibromas can be successfully removed by marginal excision, although 24% of lesions recur. No lesions have metastasized. Our patient's tendon sheath fibroma was removed by marginal excision, and the patient remained disease free 35 months postoperatively. Despite its rarity, tendon sheath fibroma should be included in the differential diagnosis of a thigh mass on physical examination or imaging, especially if it is painless, nontender, benign appearing, and present in men. PMID:22495871

  15. Cellular and molecular maturation in fetal and adult ovine calcaneal tendons

    PubMed Central

    Russo, Valentina; Mauro, Annunziata; Martelli, Alessandra; Di Giacinto, Oriana; Di Marcantonio, Lisa; Nardinocchi, Delia; Berardinelli, Paolo; Barboni, Barbara

    2015-01-01

    Processes of development during fetal life profoundly transform tendons from a plastic tissue into a highly differentiated structure, characterised by a very low ability to regenerate after injury in adulthood. Sheep tendon is frequently used as a translational model to investigate cell-based regenerative approaches. However, in contrast to other species, analytical and comparative baseline studies on the normal developmental maturation of sheep tendons from fetal through to adult life are not currently available. Thus, a detailed morphological and biochemical study was designed to characterise tissue maturation during mid- (2?months of pregnancy: 14?cm of length) and late fetal (4?months: 40?cm of length) life, through to adulthood. The results confirm that ovine tendon morphology undergoes profound transformations during this period. Endotenon was more developed in fetal tendons than in adult tissues, and its cell phenotype changed through tendon maturation. Indeed, groups of large rounded cells laying on smaller and more compacted ones expressing osteocalcin, vascular endothelial growth factor (VEGF) and nerve growth factor (NGF) were identified exclusively in fetal mid-stage tissues, and not in late fetal or adult tendons. VEGF, NGF as well as blood vessels and nerve fibers showed decreased expression during tendon development. Moreover, the endotenon of mid- and late fetuses contained identifiable cells that expressed several pluripotent stem cell markers [Telomerase Reverse Transcriptase (TERT), SRY Determining Region Y Box-2 (SOX2), Nanog Homeobox (NANOG) and Octamer Binding Transcription Factor-4A (OCT-4A)]. These cells were not identifiable in adult specimens. Ovine tendon development was also accompanied by morphological modifications to cell nuclei, and a progressive decrease in cellularity, proliferation index and expression of connexins 43 and 32. Tendon maturation was similarly characterised by modulation of several other gene expression profiles, including Collagen type I, Collagen type III, Scleraxis B, Tenomodulin, Trombospondin 4 and Osteocalcin. These gene profiles underwent a dramatic reduction in adult tissues. Transforming growth factor-1 expression (involved in collagen synthesis) underwent a similar decrease. In conclusion, these morphological studies carried out on sheep tendons at different stages of development and aging offer normal structural and molecular baseline data to allow accurate evaluation of data from subsequent interventional studies investigating tendon healing and regeneration in ovine experimental models. PMID:25546075

  16. 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

  17. 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. PMID:23227947

  18. Endoscopic Resection of Gouty Tophus of the Patellar Tendon

    PubMed Central

    Lui, Tun Hing

    2015-01-01

    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. PMID:26759781

  19. 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.

  20. 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.

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

    PubMed Central

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

    2014-01-01

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

  2. Detection of partial-thickness tears in ligaments and tendons by Stokes-polarimetry imaging

    NASA Astrophysics Data System (ADS)

    Kim, Jihoon; John, Raheel; Walsh, Joseph T.

    2008-02-01

    A Stokes polarimetry imaging (SPI) system utilizes an algorithm developed to construct degree of polarization (DoP) image maps from linearly polarized light illumination. Partial-thickness tears of turkey tendons were imaged by the SPI system in order to examine the feasibility of the system to detect partial-thickness rotator cuff tear or general tendon pathology. The rotating incident polarization angle (IPA) for the linearly polarized light provides a way to analyze different tissue types which may be sensitive to IPA variations. Degree of linear polarization (DoLP) images revealed collagen fiber structure, related to partial-thickness tears, better than standard intensity images. DoLP images also revealed structural changes in tears that are related to the tendon load. DoLP images with red-wavelength-filtered incident light may show tears and related organization of collagen fiber structure at a greater depth from the tendon surface. Degree of circular polarization (DoCP) images exhibited well the horizontal fiber orientation that is not parallel to the vertically aligned collagen fibers of the tendon. The SPI system's DOLP images reveal alterations in tendons and ligaments, which have a tissue matrix consisting largely of collagen, better than intensity images. All polarized images showed modulated intensity as the IPA was varied. The optimal detection of the partial-thickness tendon tears at a certain IPA was observed. The SPI system with varying IPA and spectral information can improve the detection of partial-thickness rotator cuff tears by higher visibility of fiber orientations and thereby improve diagnosis and treatment of tendon related injuries.

  3. The mechanical strength of side-to-side tendon repair with mismatched tendon size and shape.

    PubMed

    Fridén, J; Tirrell, T F; Bhola, S; Lieber, R L

    2015-03-01

    Tendon transfers frequently require coaptation of two mismatched tendons. In this cadaver study, ultimate load, stiffness, and Young's modulus were measured in tendon-to-tendon attachments with mismatched donor and recipient tendons, using pronator teres (PT) to extensor carpi radialis brevis (ECRB) and flexor carpi ulnaris (FCU) to extensor digitorum communis (EDC). FCU-to-EDC attachments failed at higher loads than PT-to-ECRB attachments, but they had similar modulus and stiffness values. Ultimate tensile strength of the tendon attachments exceeded the maximum predicted contraction force of any of the transferred muscles, with safety factors of four-fold for the FCU-to-EDC and two-fold for the PT-to-ECRB transfers. This implies that size and shape mismatches should not be contraindications to tendon attachment in transfers. The strength safety factors suggest that postoperative immobilization of these transfers is unnecessary. PMID:24413573

  4. 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. PMID:25877256

  5. Longitudinal In Vivo Ultrasound Observations of the Surgically Repaired Zone II Flexor Digitorum Profundus Tendon.

    PubMed

    Bűhler, Miranda; Johnson, Gillian; Meikle, Grant

    2015-11-01

    The link between the healing process and functional outcomes in the surgically repaired digital flexor tendon is poorly understood. This clinical note describes those gray-scale and power Doppler (PD) ultrasound parameters that can be used to document longitudinal change in the morphologic and dynamic properties of the surgically repaired zone II flexor digitorum profundus (FDP) tendon. The method is supported by ultrasound data obtained from three participants at five points in time post-surgically (two, four, six, 12 and 18 weeks). Longitudinal documentation of the ultrasound properties of echogenicity, defect size, tendon excursion and power Doppler signal is feasible and has the potential to explore the possible link between changes in the structural status of surgically repaired flexor tendons and associated clinical outcomes. PMID:26304499

  6. The enthesis: a review of the tendon-to-bone insertion

    PubMed Central

    Apostolakos, John; Durant, Thomas JS; Dwyer, Corey R.; Russell, Ryan P.; Weinreb, Jeffrey H.; Alaee, Farhang; Beitzel, Knut; McCarthy, Mary Beth; Cote, Mark P.; Mazzocca, Augustus D.

    2014-01-01

    Summary The integration of tendon into bone occurs at a specialized interface known as the enthesis. The fibrous tendon to bone enthesis is established through a structurally continuous gradient from uncalcified tendon to calcified bone. The enthesis exhibits gradients in tissue organization classified into four distinct zones with varying cellular compositions, mechanical properties, and functions in order to facilitate joint movement. Damage to tendinous insertions is common in the field of orthopaedic medicine and often involves surgical intervention that requires the attempted recreation of the natural organization of tendon into bone. The difficulty associated with recreating the distinct organization may account for the surgical challenges associated with reconstruction of damaged insertion sites. These procedures are often associated with high failure rates and consequently require revision procedures. Management of tendinous injuries and reconstruction of the insertion site is becoming a popular topic in the field of orthopaedic medicine. PMID:25489552

  7. Time-dependent mechanical behavior of sheep digital tendons, including the effects of preconditioning.

    PubMed

    Sverdlik, A; Lanir, Y

    2002-02-01

    The time-dependent mechanical properties of sheep digital extensor tendons were studied by sequences of stress-relaxation tests. The results exhibited irreversible preconditioning and reversible viscoelasticity. Preconditioning effects were manifested by stress decay during consecutive stretch cycles to the same strain level, accompanied by elongation of the tendon's reference length. They intensified with increased strain level, and were reduced or became negligible as the strain decreased. The significance of intrinsic response mechanisms was studied via a structural model that includes viscoelasticity, preconditioning, and morphology of the tendon's collagen fibers. Model/data comparisons showed good agreement and good predictive power, suggesting that preconditioning can be integrated into comprehensive material characterization of tendons. PMID:11871608

  8. Augmentation of tendon-to-bone healing.

    PubMed

    Atesok, Kivanc; Fu, Freddie H; Wolf, Megan R; Ochi, Mitsuo; Jazrawi, Laith M; Doral, M Nedim; Lubowitz, James H; Rodeo, Scott A

    2014-03-19

    Tendon-to-bone healing is vital to the ultimate success of the various surgical procedures performed to repair injured tendons. Achieving tendon-to-bone healing that is functionally and biologically similar to native anatomy can be challenging because of the limited regeneration capacity of the tendon-bone interface. Orthopaedic basic-science research strategies aiming to augment tendon-to-bone healing include the use of osteoinductive growth factors, platelet-rich plasma, gene therapy, enveloping the grafts with periosteum, osteoconductive materials, cell-based therapies, biodegradable scaffolds, and biomimetic patches. Low-intensity pulsed ultrasound and extracorporeal shockwave treatment may affect tendon-to-bone healing by means of mechanical forces that stimulate biological cascades at the insertion site. Application of various loading methods and immobilization times influence the stress forces acting on the recently repaired tendon-to-bone attachment, which eventually may change the biological dynamics of the interface. Other approaches, such as the use of coated sutures and interference screws, aim to deliver biological factors while achieving mechanical stability by means of various fixators. Controlled Level-I human trials are required to confirm the promising results from in vitro or animal research studies elucidating the mechanisms underlying tendon-to-bone healing and to translate these results into clinical practice. PMID:24647509

  9. The pathology of flexor tendon repair.

    PubMed

    Matthews, P

    1979-10-01

    This paper discusses the problems of failure after tendon repair. For a long time the subject has been dominated by the problem of adhesion formation. Recent work has shown that this is not inevitable, and consideration of other factors, particularly the nutrition of tendon tissue is leading to the possibilities of other methods of treatment. PMID:520866

  10. 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.

  11. 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

  12. Ultrasonic evaluation of flood gate tendons

    NASA Astrophysics Data System (ADS)

    Thomas, Graham H.; Brown, Albert E.

    1998-03-01

    Our water resources infrastructure is susceptible to aging degradation just like the rest of this country's infrastructure. A critical component of the water supply system is the flood gate that controls the outflow from dams. Long steel rods called tendons attach these radial gates to the concrete in the dam. The tendons are typically forty feet long and over one inch in diameter. Moisture may seep into the grout around the tendons and cause corrosion. Lawrence Livermore National Laboratory is working with the California Department of Water Resources to develop advanced ultrasonic techniques for nondestructively inspecting their tendons. A unique transducer was designed and fabricated to interrogate the entire tendon. A robust, portable unit was assembled that included a computer controlled data acquisition system and specialized data processing software to analyze the ultrasonic signals. This system was tested on laboratory specimens and is presently being fielded at two dam sites.

  13. Examination of the Biceps Tendon.

    PubMed

    McFarland, Edward G; Borade, Amrut

    2016-01-01

    The examination of the shoulder for conditions involving the biceps tendon continues to be challenging. Numerous examination tests for biceps and superior labrum anterior and posterior (SLAP) lesions have been scientifically evaluated. This section reports on how to perform these tests and summarizes the clinical utility of the tests. Many of the tests for the examination of the biceps and for SLAP lesions do not have high sensitivity and specificity, which limits their usefulness. Although the dynamic shear test has promise for making the diagnosis of SLAP lesions, the studies reporting its clinical utility are disparate. PMID:26614467

  14. 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. PMID:25568677

  15. Therapeutic potential of mesenchymal stem cells to treat Achilles tendon injuries.

    PubMed

    Vieira, M H C; Oliveira, R J; Eça, L P M; Pereira, I S O; Hermeto, L C; Matuo, R; Fernandes, W S; Silva, R A; Antoniolli, A C M B

    2014-01-01

    Rupture of the Achilles tendon diminishes quality of life. The gold-standard therapy is a surgical suture, but this presents complications, including wound formation and inflammation. These complications spurred evaluation of the therapeutic potential of mesenchymal stem cells (MSCs) from adipose tissue. New Zealand rabbits were divided into 6 groups (three treatments with two time points each) evaluated at either 14 or 28 days after surgery: cross section of the Achilles tendon (CSAT); CSAT + Suture; and CSAT + MSC. A comparison between all groups at both time points showed a statistically significant increase in capillaries and in the structural organization of collagen in the healed tendon in the CSAT + Suture and CSAT + MSC groups at the 14-day assessment. Comparison between the two time points within the same group showed a statistically significant decrease in the inflammatory process and an increase in the structural organization of collagen in the CSAT and CSAT + MSC groups. A study of the genomic integrity of the cells suggested a linear correlation between an increase of injuries and culture time. Thus, MSC transplantation is a good alternative for treatment of Achilles tendon ruptures because it may be conducted without surgery and tendon suture and, therefore, has no risk of adverse effects resulting from the surgical wound or inflammation caused by nonabsorbable sutures. Furthermore, this alternative treatment exhibits a better capacity for wound healing and maintaining the original tendon architecture, depending on the arrangement of the collagen fibers, and has important therapeutic potential. PMID:25511027

  16. Functional Grading of Mineral and Collagen in the Attachment of Tendon to Bone

    PubMed Central

    Genin, Guy M.; Kent, Alistair; Birman, Victor; Wopenka, Brigitte; Pasteris, Jill D.; Marquez, Pablo J.; Thomopoulos, Stavros

    2009-01-01

    Abstract Attachment of dissimilar materials is a major challenge because high levels of localized stress may develop at their interfaces. An effective biologic solution to this problem exists at one of nature's most extreme interfaces: the attachment of tendon (a compliant, structural “soft tissue”) to bone (a stiff, structural “hard tissue”). The goal of our study was to develop biomechanical models to describe how the tendon-to-bone insertion derives its mechanical properties. We examined the tendon-to-bone insertion and found two factors that give the tendon-to-bone transition a unique grading in mechanical properties: 1), a gradation in mineral concentration, measured by Raman spectroscopy; and 2), a gradation in collagen fiber orientation, measured by polarized light microscopy. Our measurements motivate a new physiological picture of the tissue that achieves this transition, the tendon-to-bone insertion, as a continuous, functionally graded material. Our biomechanical model suggests that the experimentally observed increase in mineral accumulation within collagen fibers can provide significant stiffening of the partially mineralized fibers, but only for concentrations of mineral above a “percolation threshold” corresponding to formation of a mechanically continuous mineral network within each collagen fiber (e.g., the case of mineral connectivity extending from one end of the fiber to the other). Increasing dispersion in the orientation distribution of collagen fibers from tendon to bone is a second major determinant of tissue stiffness. The combination of these two factors may explain the nonmonotonic variation of stiffness over the length of the tendon-to-bone insertion reported previously. Our models explain how tendon-to-bone attachment is achieved through a functionally graded material composition, and provide targets for tissue engineered surgical interventions and biomimetic material interfaces. PMID:19686644

  17. Smad8/BMP2–Engineered Mesenchymal Stem Cells Induce Accelerated Recovery of the Biomechanical Properties of the Achilles Tendon

    PubMed Central

    Pelled, Gadi; Snedeker, Jess G.; Ben-Arav, Ayelet; Rigozzi, Samuela; Zilberman, Yoram; Kimelman-Bleich, Nadav; Gazit, Zulma; Müller, Ralph; Gazit, Dan

    2012-01-01

    Summary Tendon tissue regeneration is an important goal for orthopedic medicine. We hypothesized that implantation of Smad8/BMP2–engineered MSCs in a full-thickness defect of the Achilles tendon (AT) would induce regeneration of tissue with improved biomechanical properties. A 2 mm defect was created in the distal region of murine ATs. The injured tendons were then sutured together or given implants of genetically engineered MSCs (GE group), nonengineered MSCs (CH3 group), or fibrin gel containing no cells (FG group). Three weeks later the mice were killed, and their healing tendons were excised and processed for histological or biomechanical analysis. A biomechanical analysis showed that tendons that received implants of genetically engineered MSCs had the highest effective stiffness (> 70% greater than natural healing, p < 0.001) and elastic modulus. There were no significant differences in either ultimate load or maximum stress among the treatment groups. Histological analysis revealed a tendon-like structure with elongated cells mainly in the GE group. ATs that had been implanted with Smad8/BMP2–engineered stem cells displayed a better material distribution and functional recovery than control groups. While additional study is required to determine long-term effects of GE MSCs on tendon healing, we conclude that genetically engineered MSCs may be a promising therapeutic tool for accelerating short-term functional recovery in the treatment of tendon injuries. PMID:22696396

  18. Smad8/BMP2-engineered mesenchymal stem cells induce accelerated recovery of the biomechanical properties of the Achilles tendon.

    PubMed

    Pelled, Gadi; Snedeker, Jess G; Ben-Arav, Ayelet; Rigozzi, Samuela; Zilberman, Yoram; Kimelman-Bleich, Nadav; Gazit, Zulma; Müller, Ralph; Gazit, Dan

    2012-12-01

    Tendon tissue regeneration is an important goal for orthopedic medicine. We hypothesized that implantation of Smad8/BMP2-engineered MSCs in a full-thickness defect of the Achilles tendon (AT) would induce regeneration of tissue with improved biomechanical properties. A 2 mm defect was created in the distal region of murine ATs. The injured tendons were then sutured together or given implants of genetically engineered MSCs (GE group), non-engineered MSCs (CH3 group), or fibrin gel containing no cells (FG group). Three weeks later the mice were killed, and their healing tendons were excised and processed for histological or biomechanical analysis. A biomechanical analysis showed that tendons that received implants of genetically engineered MSCs had the highest effective stiffness (>70% greater than natural healing, p < 0.001) and elastic modulus. There were no significant differences in either ultimate load or maximum stress among the treatment groups. Histological analysis revealed a tendon-like structure with elongated cells mainly in the GE group. ATs that had been implanted with Smad8/BMP2-engineered stem cells displayed a better material distribution and functional recovery than control groups. While additional study is required to determine long-term effects of GE MSCs on tendon healing, we conclude that genetically engineered MSCs may be a promising therapeutic tool for accelerating short-term functional recovery in the treatment of tendon injuries. PMID:22696396

  19. Anterior cruciate ligament reconstruction: clinical outcomes of patella tendon and hamstring tendon grafts.

    PubMed

    Gulick, Dawn T; Yoder, Heather N

    2002-09-01

    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

  20. 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

  1. Bone Morphogenetic Protein 7 (BMP-7) Influences Tendon-Bone Integration In Vitro

    PubMed Central

    Schwarting, Tim; Lechler, Philipp; Struewer, Johannes; Ambrock, Marius; Frangen, Thomas Manfred; Ruchholtz, Steffen; Ziring, Ewgeni; Frink, Michael

    2015-01-01

    Introduction Successful graft ingrowth following reconstruction of the anterior cruciate ligament is governed by complex biological processes at the tendon-bone interface. The aim of this study was to investigate in an in vitro study the effects of bone morphogenetic protein 7 (BMP-7) on tendon-bone integration. Materials and Methods To study the biological effects of BMP-7 on the process of tendon-bone-integration, two independent in vitro models were used. The first model involved the mono- and coculture of bovine tendon specimens and primary bovine osteoblasts with and without BMP-7 exposure. The second model comprised the mono- and coculture of primary bovine osteoblasts and fibroblasts. Alkaline phosphatase (ALP), lactate dehydrogenase (LDH), lactate and osteocalcin (OCN) were analyzed by ELISA. Histological analysis and electron microscopy of the tendon specimens were performed. Results In both models, positive effects of BMP-7 on ALP enzyme activity were observed (p<0.001). Additionally, similar results were noted for LDH activity and lactate concentration. BMP-7 stimulation led to a significant increase in OCN expression. Whereas the effects of BMP-7 on tendon monoculture peaked during an early phase of the experiment (p<0.001), the cocultures showed a maximal increase during the later stages (p<0.001). The histological analysis showed a stimulating effect of BMP-7 on extracellular matrix formation. Organized ossification zones and calcium carbonate-like structures were only observed in the BMP-stimulated cell cultures. Discussion This study showed the positive effects of BMP-7 on the biological process of tendon-bone integration in vitro. Histological signs of improved mineralization were paralleled by increased rates of osteoblast-specific protein levels in primary bovine osteoblasts and fibroblasts. Conclusion Our findings indicated a role for BMP-7 as an adjuvant therapeutic agent in the treatment of ligamentous injuries, and they emphasized the importance of the transdifferentiation process of tendinous fibroblasts at the tendon-bone interface. PMID:25643349

  2. 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.

  3. Osmotic pressure induced tensile forces in tendon collagen

    PubMed Central

    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. PMID:25608644

  4. 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.

  5. [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.

  6. ACL reconstruction using bone-tendon-bone graft engineered from the semitendinosus tendon by injection of recombinant BMP-2 in a rabbit model.

    PubMed

    Hashimoto, Yusuke; Naka, Yoshifumi; Fukunaga, Kenji; Nakamura, Hiroaki; Takaoka, Kunio

    2011-12-01

    We attempted to generate a bone-tendon-bone structure by injecting human-type recombinant human bone morphogenetic protein-2 (rhBMP-2) into the semitendinosus tendon, and an anterior cruciate ligament (ACL) defect was reconstructed by grafting the engineered bone-tendon-bone graft. Two ossicles with a separation distance of 1 cm were generated within the left semitendinosus tendon of a rabbit 6 weeks after the injection of rhBMP-2 (15 µg at each site). The engineered bone-tendon-bone graft was transplanted in order to reconstruct the ACL by passing the graft through the bone tunnels. In the control group, the ACL was reconstructed with the semitendinosus tendon without BMP-2 using the same methods as those used in the experimental group. The animals were harvested at 4 or 8 weeks after surgery and examined by radiographic, histological, and biomechanical methods. In the experimental group, ossicles in the bone-tendon-bone graft were successfully integrated into the host bone of the femur and tibia. Histological analysis revealed that characteristic features identical to the normal direct insertion morphology had been restored. Biomechanical pull-out testing showed that the ultimate failure load and stiffness of the reconstructed ACL in the experimental group were significantly higher than those in the control group at both 4 and 8 weeks (p < 0.05). These results indicate the potential of regenerative reconstruction of the ACL, and the reconstruction resulted in the restoration of morphology and function equivalent to those of the normal ACL. PMID:21557301

  7. Arthroscopically Assisted Latissimus Dorsi Tendon Transfer in Beach-Chair Position.

    PubMed

    Jermolajevas, Viktoras; Kordasiewicz, Bartlomiej

    2015-08-01

    Irreparable rotator cuff tears remain a surgical problem. The open technique of latissimus dorsi (LD) tendon transfer to "replace" the irreparable rotator cuff is already well known. The aim of this article is to present a modified arthroscopically assisted LD tendon transfer technique. This technique was adopted to operate on patients in the beach-chair position with several improvements in tendon harvesting and fixation. It can be divided into 6 steps, and only 1 step-LD muscle and tendon release-is performed open. The advantages of the arthroscopic procedure are sparing of the deltoid muscle, the possibility of repairing the subscapularis tendon, and the ability to visualize structures at risk while performing tendon harvesting (radial nerve) and passing into the subacromial space (axillary nerve). It is performed in a similar manner to standard rotator cuff surgery-the beach-chair position does not need any modification, and no sophisticated equipment for either the open or arthroscopic part of the procedure is necessary. Nevertheless, this is a challenging procedure and should only be attempted after training, as well as extensive practice. PMID:26759777

  8. Alpine Skiing With total knee ArthroPlasty (ASWAP): effect on tendon properties.

    PubMed

    Kösters, A; Rieder, F; Wiesinger, H-P; Dorn, U; Hofstaedter, T; Fink, C; Müller, E; Seynnes, O R

    2015-08-01

    The aim of this study was to investigate the effect of alpine skiing on patellar tendon properties in patients with total knee arthroplasty (TKA). Thirty-one adults (70.4?±?4.7 years) with unilateral TKA were recruited 2.7?±?0.9 years after surgery and assigned to an intervention (IG) or a control group (CG). The IG underwent a 12-week guided skiing program. Tendon stiffness, Young's modulus, and cross-sectional area (CSA) were measured before and after the intervention. In both groups, mean tendon CSA was 28% (P?tendon properties. After training, stiffness increased in the IG by 5.8% and 15.8%, respectively, in the OP and NOP legs. Likewise, mean CSA increased in the IG by 2.9% in the OP and 3.8% in the NOP leg, whereas no significant changes were found for the Young's modulus. None of the tendon parameters changed in the CG. Results indicate that patellar tendon structure and/or loading pattern are altered following TKA, but this tissue seems to retain its adaptation capacity. Further, alpine skiing appears to offer a suitable rehabilitation strategy for TKA patients. PMID:26083704

  9. Arthroscopically Assisted Latissimus Dorsi Tendon Transfer in Beach-Chair Position

    PubMed Central

    Jermolajevas, Viktoras; Kordasiewicz, Bartlomiej

    2015-01-01

    Irreparable rotator cuff tears remain a surgical problem. The open technique of latissimus dorsi (LD) tendon transfer to “replace” the irreparable rotator cuff is already well known. The aim of this article is to present a modified arthroscopically assisted LD tendon transfer technique. This technique was adopted to operate on patients in the beach-chair position with several improvements in tendon harvesting and fixation. It can be divided into 6 steps, and only 1 step—LD muscle and tendon release—is performed open. The advantages of the arthroscopic procedure are sparing of the deltoid muscle, the possibility of repairing the subscapularis tendon, and the ability to visualize structures at risk while performing tendon harvesting (radial nerve) and passing into the subacromial space (axillary nerve). It is performed in a similar manner to standard rotator cuff surgery—the beach-chair position does not need any modification, and no sophisticated equipment for either the open or arthroscopic part of the procedure is necessary. Nevertheless, this is a challenging procedure and should only be attempted after training, as well as extensive practice. PMID:26759777

  10. 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

  11. Combined anterior tibial tendon rupture and posterior tibial tendon dysfunction in advanced flatfoot.

    PubMed

    Frigg, Arno Martin; Valderrabano, Victor; Kundert, Hans-Peter; Hintermann, Beat

    2006-01-01

    The combination of spontaneous anterior tibial tendon rupture and posterior tibial tendon dysfunction has rarely been reported in the literature. This is a case report of a 78-year-old patient presenting with a history of longstanding, progressive flatfoot deformity, clinically grade III posterior tibial tendon dysfunction, and dropfoot gait. Radiographic films revealed severe flatfoot, and the clinical examination was consistent with a complete rupture of the anterior tibial tendon and severe posterior tibial tendon degeneration as well as rupture of the spring and deltoid ligaments. Treatment by triple arthrodesis and repair of the anterior tibial tendon affected pain relief and clinical as well as radiographic correction at the 4-month postoperative assessment. PMID:17145469

  12. Late flexor digitorum longus tendon rupture after transfer for posterior tibial tendon insufficiency: a case report.

    PubMed

    Ouzounian, T J

    1995-08-01

    A 64-year-old woman was treated for an idiopathic complete rupture of the posterior tibial tendon with transfer of the flexor digitorum longus tendon to the navicular. After an initial excellent result, she returned 41 months later after experiencing a sudden pop in the medial retromalleolar area, followed by progressive medial ankle pain. At reoperation, a complete rupture of the flexor digitorum longus tendon was noted at its insertion into the navicular. Reconstruction was performed utilizing a sliding lengthening of the flexor digitorum longus tendon and reattachment to the navicular with a suture anchor. Clinical improvement was noted at the 12-month follow-up evaluation. This case presentation is of clinical interest, as late acute failure of a flexor digitorum longus tendon transfer for posterior tibial tendon rupture has not been reported previously. PMID:8520667

  13. Catastrophic Failure of an Infected Achilles Tendon Rupture Repair Managed with Combined Flexor Hallucis Longus and Peroneus Brevis Tendon Transfer.

    PubMed

    Simonson, Devin C; Elliott, Andrew D; Roukis, Thomas S

    2016-01-01

    Deep infection is one of the most devastating complications following repair of an Achilles tendon rupture. Treatment requires not only culture-driven antibiotic therapy, but more importantly, appropriate débridement of some or even all of the Achilles tendon. This may necessitate delayed reconstruction of the Achilles tendon. The authors present a successful case of reconstruction of a chronically infected Achilles tendon in an otherwise healthy 43-year-old man via a multistaged approach using the flexor hallucis longus and peroneus brevis tendons. We also provide a brief review of the literature regarding local tendon transfer used in the reconstruction of Achilles tendon rupture. PMID:26590732

  14. Principles and Biomechanical Considerations of Tendon Transfers.

    PubMed

    Walton, Laura; Villani, Matthew F

    2016-01-01

    Whether performed as a primary procedure or used to augment and support osseous reconstruction, tendon transfers are a key skill for the foot and ankle surgeon. Understanding the biomechanics preoperative and postoperatively is essential in performing appropriate procedures and in supporting patients through the rehabilitation process. Often the complexity of tendon transfer surgery is lost because it is deemed a soft tissue procedure and in theory should be less complex than osseous procedures. However, the dynamic nature of musculature and tendons require a deeper understanding of surgical and biomechanical concepts. PMID:26590719

  15. 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. PMID:26614474

  16. 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

  17. 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

  18. Intrasynovial Tendon Graft for Chronic Flexor Tendon Laceration of the Finger: A Case Report

    PubMed Central

    Sasaki, Jun; Itsubo, Toshiro; Nakamura, Koichi; Hayashi, Masanori; Uchiyama, Shigeharu; Kato, Hiroyuki

    2013-01-01

    We present the case of a patient with flexor digitorum profundus tendon laceration at the A2 pulley level caused by an injury to the base of the right ring finger by a knife. The patient was treated by flexor tendon reconstruction from the palm to the fingertip by using the left second toe flexor tendon as a graft, which improved the active range of motion. Further improvement was achieved by subsequent tenolysis, which eventually restored nearly normal function. Our experience with this case indicates that the intrasynovial tendon is a reasonable graft source for the synovial space in fingers and may enable restoration of excellent postoperative function. PMID:24015158

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

    PubMed Central

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

    2012-01-01

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

  20. 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. PMID:25736446

  1. Biomechanical behavior of muscle-tendon complex during dynamic human movements.

    PubMed

    Fukashiro, Senshi; Hay, Dean C; Nagano, Akinori

    2006-05-01

    This paper reviews the research findings regarding the force and length changes of the muscle-tendon complex during dynamic human movements, especially those using ultrasonography and computer simulation. The use of ultrasonography demonstrated that the tendinous structures of the muscle-tendon complex are compliant enough to influence the biomechanical behavior (length change, shortening velocity, and so on) of fascicles substantially. It was discussed that the fascicles are a force generator rather than a work generator; the tendinous structures function not only as an energy re-distributor but also as a power amplifier, and the interaction between fascicles and tendinous structures is essential for generating higher joint power outputs during the late pushoff phase in human vertical jumping. This phenomenon could be explained based on the force-length/velocity relationships of each element (contractile and series elastic elements) in the muscle-tendon complex during movements. Through computer simulation using a Hill-type muscle-tendon complex model, the benefit of making a countermovement was examined in relation to the compliance of the muscle-tendon complex and the length ratio between the contractile and series elastic elements. Also, the integral roles of the series elastic element were simulated in a cyclic human heel-raise exercise. It was suggested that the storage and reutilization of elastic energy by the tendinous structures play an important role in enhancing work output and movement efficiency in many sorts of human movements. PMID:16871004

  2. 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(?ten/?ten). Targeting was specific, resulting in collagen V-null tendons and ligaments. Col5a1(?ten/?ten) 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. PMID:25797646

  3. 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

  4. Common Disorders of the Achilles Tendon

    MedlinePLUS

    ... after periods of rest, then improves somewhat with motion but later worsens with increased activity. Tenderness, or ... foot and ankle and evaluate the range of motion and condition of the tendon. The extent of ...

  5. A posterior tibial tendon skipping rope.

    PubMed

    van Sterkenburg, M N; Haverkamp, D; van Dijk, C N; Kerkhoffs, G M M J

    2010-12-01

    This report presents an athletic patient with swelling and progressive pain on the posteromedial side of his right ankle on weight bearing. MRI demonstrated tenosynovitis and suspicion of a length rupture. On posterior tibial tendoscopy, there was no rupture, but medial from the tendon a tissue cord came into view, causing impingement on the tendon at the level of maximum pain. The cord was released and 2 weeks and 1 year after the procedure the patient reported no complaints. PMID:20556356

  6. [Primary repair of extensor tendon injuries of the hand].

    PubMed

    Mascharka, Z

    2007-06-01

    Knowledge of the functional anatomy of the extensor tendons with the sliding mechanism is essential for better understanding the surgical therapy and the postoperative care in the different trauma zones of the extensor tendon. In addition the localization of the injury is very important for the clinical findings, therapy, after-care and long term prognosis. Anatomical facts, injury mechanisms and associated injuries have to be considered in the therapy concept. Several therapy possibilities are known: immobilizing with splint for the closed rupture in zone I, reinsertion in zone III (with a temporary Kirschner-wire-pinning), tendon suture, tendon transplantation or transposition. Controlled mobilization after suture should be aspired (similar to the one of the flexor tendon) especially after squeezing, multi tendon injuries, tendon transplantations or injuries in zone VII. Pathological and iatrogenic tendon lesions are special forms of tendon injuries. PMID:17559022

  7. 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.

  8. Acute Patellar Tendon Rupture after Total Knee Arthroplasty Revision

    PubMed Central

    Rhee, Seung Joon; Pham, The Hien

    2015-01-01

    Patellar tendon rupture is a catastrophic complication following total knee arthroplasty (TKA). Though revision TKA has been suspected of being a predisposing factor for the occurrence of patellar tendon rupture, there are few reports on patellar tendon rupture after revision TKA. Here, we present a case of acute patellar tendon rupture that occurred after TKA revision. In the patient, the patellar tendon was so thin and could not be repaired, and accordingly was sutured end to end. We used the anterior tibialis tendon allograft to augment the poor quality patellar tendon tissue. Fixation of the allograft was done by using the bone tunnel created through tibial tuberosity and suturing the allograft to the patellar tendon and quadriceps tendon. The patient was instructed to wear a full extension knee splint and was kept non-weight bearing for 6 weeks after operation. Full knee extension could be achieved 6 weeks postoperatively. PMID:26060612

  9. Condition Assessment of PC Tendon Duct Filling by Elastic Wave Velocity Mapping

    PubMed Central

    Liu, Kit Fook; Mehrabi, Nima; Yoshikazu, Kobayashi; Shiotani, Tomoki

    2014-01-01

    Imaging techniques are high in demand for modern nondestructive evaluation of large-scale concrete structures. The travel-time tomography (TTT) technique, which is based on the principle of mapping the change of propagation velocity of transient elastic waves in a measured object, has found increasing application for assessing in situ concrete structures. The primary aim of this technique is to detect defects that exist in a structure. The TTT technique can offer an effective means for assessing tendon duct filling of prestressed concrete (PC) elements. This study is aimed at clarifying some of the issues pertaining to the reliability of the technique for this purpose, such as sensor arrangement, model, meshing, type of tendon sheath, thickness of sheath, and material type as well as the scale of inhomogeneity. The work involved 2D simulations of wave motions, signal processing to extract travel time of waves, and tomography reconstruction computation for velocity mapping of defect in tendon duct. PMID:24737961

  10. 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

  11. Combination of hormone replacement therapy and high physical activity is associated with differences in Achilles tendon size in monozygotic female twin pairs.

    PubMed

    Finni, T; Kovanen, V; Ronkainen, P H A; Pöllänen, E; Bashford, G R; Kaprio, J; Alén, M; Kujala, U M; Sipilä, S

    2009-04-01

    Estrogen concentration has been suggested to play a role in tendon abnormalities and injury. In physically active postmenopausal women, hormone replacement therapy (HRT) has been suggested to decrease tendon diameter. We hypothesized that HRT use and physical activity are associated with Achilles tendon size and tissue structure. The study applied cotwin analysis of fourteen 54- to 62-yr-old identical female twin pairs with current discordance for HRT use for an average of 7 yr. Achilles tendon thickness and cross-sectional areas were determined by ultrasonography, and tendon structural organization was analyzed from the images using linear discriminant analysis (LDA). Maximal voluntary and twitch torques from plantar flexor muscles were measured. Serum levels of estradiol, estrone, testosterone, and sex hormone binding globulin were analyzed. Total daily metabolic equivalent score (MET-h/day) was calculated from physical activity questionnaires. Results showed that, in five physically active (MET > 4) pairs, the cotwins receiving HRT had greater estradiol level (P = 0.043) and smaller tendon cross-sectional area than their sisters (63 vs. 71 mm(2), P = 0.043). Among all pairs, Achilles tendon thickness and cross-sectional area did not significantly differ between HRT using and nonusing twin sisters. Intrapair correlation for Achilles tendon thickness was high, despite HRT use discordance (r = 0.84, P < 0.001). LDA distinguished different tendon structure only from two of six examined twin pairs who had a similar level of physical activity. In conclusion, the effect of HRT on Achilles tendon characteristics independent of genetic confounding may be present only in the presence of sufficient physical activity. In physically active twin pairs, the higher level of estrogen seems to be associated with smaller tendon size. PMID:19164771

  12. 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. PMID:21900004

  13. A reappraisal of the prevalence and clinical importance of left ventricular false tendons in children and adults.

    PubMed Central

    Malouf, J; Gharzuddine, W; Kutayli, F

    1986-01-01

    The prevalence and clinical importance of false tendons were studied in 488 consecutive patients referred for echocardiography. Two hundred and eighty three (58%) patients had acquired heart disease, 91 (19%) had congenital heart disease, and 114 (23%) had normal hearts. Sixty six patients with normal hearts had innocent systolic murmurs and one had recurrent ventricular tachycardia. The overall prevalence of false tendons was 25% compared with 1.6% in a retrospective analysis of 763 cross sectional echocardiograms. When patients with innocent murmurs were excluded from statistical analysis, there was no significant difference in the prevalence of these tendons between children and adults, boys and girls, men and women, or between patients with acquired or congenital heart disease and normal patients. The prevalence of false tendons in patients with dilated left ventricles (57%), however, resembled that seen in necropsy studies. The prevalence of false tendons in patients with an innocent systolic murmur was 76% in children and 40% in adults, with an overall prevalence of 52%. False tendons are a common echocardiographic finding of no clinical importance except for their possible role in the genesis of innocent murmurs and ventricular arrhythmias. The echocardiographic detection of false tendons increases considerably when these structures are specifically sought and in conditions that result in left ventricular chamber dilatation. Images Fig. 1 Fig. 2 Fig. 3 PMID:3718798

  14. 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. PMID:25122555

  15. 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. PMID:26718836

  16. Endoscopic Flexor Hallucis Longus Tendon Transfer for Chronic Achilles Tendon Rupture.

    PubMed

    Lui, Tun Hing; Chan, Wai Chung; Maffulli, Nicola

    2016-03-01

    Chronic Achilles tendon rupture posed significant disability to the patients. Flexor hallucis longus (FHL) transfer can be used to restore the plantarflexion power of the ankle. Traditionally, a long medial incision with extensive soft tissue dissection is needed for FHL transfer. With the advance in flexor hallucis tendoscopy, endoscopic FHL tendon transfer can be performed without extensive soft tissue dissection. PMID:26752778

  17. Patellar tendon and tibial tubercle reconstruction using quadriceps tendon with patellar bone plug autograft.

    PubMed

    Edwards, T B; Lewis, J E; Guanche, C A

    1997-05-01

    This report describes a technique for the reconstruction of a patellar tendon-tibial tubercle deficiency. This technique uses an easy-to-harvest, low-morbidity graft (autogenous quadriceps tendon), while allowing aggressive rehabilitation as a result of the strength of the graft. PMID:9258831

  18. Depiction of Achilles Tendon Microstructure In-Vivo Using High-Resolution 3D Ultrashort Echo-Time MRI at 7T

    PubMed Central

    Han, Misung; Larson, Peder E. Z.; Liu, Jing; Krug, Roland

    2014-01-01

    Objectives To demonstrate the feasibility of depicting the internal structure of the Achilles tendon in vivo using high-resolution 3D ultrashort echo-time (UTE) magnetic resonance imaging (MRI) at 7T. Materials and Methods For our UTE imaging, a minimum-phase radiofrequency pulse and an anisotropic field-of-view 3D radial acquisition were used to minimize the echo time and scan time. A fat saturation pulse was applied every eight spoke acquisitions to reduce blurring and chemical shift artifacts from fat and to improve dynamic range of the tendon signal. Five healthy volunteers and one patient were scanned with an isotropic spatial resolution of up to 0.6 mm. Fat-suppressed UTE images were qualitatively evaluated and compared to non-fat-suppressed UTE images and longer echo-time images. Results High-resolution UTE imaging was able to visualize the microstructure of the Achilles tendon. Fat suppression substantially improved the depiction of the internal structure. The UTE images revealed a fascicular pattern in the Achilles tendon and fibrocartilage at the tendon insertion. In a patient who had tendon elongation surgery after birth there was clear depiction of disrupted tendon structure. Conclusions High-resolution fat-suppressed 3D UTE imaging at 7T allows for evaluation of the Achilles tendon microstructure in vivo. PMID:24500089

  19. Muscle loading is necessary for the formation of a functional tendon enthesis

    PubMed Central

    Schwartz, AG; Lipner, JH; Pasteris, JD; Genin, GM; Thomopoulos, S

    2013-01-01

    Muscle forces are essential for skeletal patterning during development. Eliminating muscle forces, e.g., through paralysis, leads to bone and joint deformities. Botulinum toxin (BtxA)-induced paralysis of mouse rotator cuffs throughout postnatal development closely mimics neonatal brachial plexus palsy, a significant clinical condition in infants. In these mice, the tendon-to-bone attachment (i.e., the tendon enthesis) presents defects in mineral accumulation and fibrocartilage formation, presumably impairing the function of the tissue. The objective of the current study was to investigate the functional consequences of muscle unloading using BtxA on the developing supraspinatus tendon enthesis. We found that the maximum endurable load and stiffness of the supraspinatus tendon attachment decreased after four and eight weeks of post-natal BtxA-muscle unloading relative to controls. Tendon cross-sectional area was significantly reduced by BtxA-unloading, suggesting that the reduction of mechanical function resulted in part from geometric changes. However, strength, modulus, and toughness were also decreased in the BtxA-unloaded group compared to controls, indicating a decrease in tissue quality. Polarized-light microscopy and Raman microprobe analysis were used to determine collagen fiber alignment and mineral characteristics, respectively, in the tendon enthesis that might contribute to the reduced biomechanical performance in BtxA-unloaded shoulders. Collagen fiber alignment was significantly reduced in BtxA-unloaded shoulders. The mineral-to-matrix ratio in mineralized fibrocartilage was not affected by loading. However, the crystallographic atomic order of the hydroxylapatite phase (a measure of crystallinity) was reduced and the amount of carbonate (substituting for phosphate) in the hydroxylapatite crystals was increased. Taken together, these micrometer-scale structural and compositional changes partly explain the observed decreases in the mechanical functionality of the tendon enthesis in the absence of muscle loading. PMID:23542869

  20. Efficacy of hyaluronic acid/nonsteroidal anti-inflammatory drug systems in preventing postsurgical tendon adhesions.

    PubMed

    Miller, J A; Ferguson, R L; Powers, D L; Burns, J W; Shalaby, S W

    1997-01-01

    Tendon adhesion is acknowledged to be a function of both an overwhelming inflammatory response at the surgical site and the loss of physical separation that is normally present between the tendons and the synovial sheath. Adhesions bind the flexor tendons to each other and to surrounding structures, interfering with their normal gliding function. The clinical result of adhesion formation following flexor tendon surgery is poor digital function. This study investigated the effect of intraoperative treatments of high viscosity absorbable gels made of various combinations of hyaluronic acid and nonsteroidal anti-inflammatory drugs, on adhesion formation in a leghorn chicken flexor tendon model. Forty-eight mature, white leghorn chickens were used to verify the surgical model and to test five different gel treatments. The gels were formed from: 2% sodium hyaluronate in phosphate buffered saline alone or combined with 1 mg/mL tolmetin sodium; 1 mg/mL naproxen sodium; 0.216 g/mL calcium acetate; or 0.216 g/mL calcium acetate plus 1 mg/mL naproxen sodium. The gels were applied by injecting 0.2 mL of the specified composition into the intrasheath space near the conclusion of the surgical procedure. Gross and histological evaluations were conducted to analyze the efficacy. All of the treatments significant reduced the extent and severity of postsurgical tendon adhesion in this animal model as compared with the control (no gel treatment) (p < 0.05). The combination of naproxen sodium and calcium acetate in a high viscosity sodium hyaluronate carrier was the most effective composition. The combination of a high viscosity gel and nonsteroidal anti-inflammatory drugs appears to maintain the natural separation between the tendons and their sheaths and decrease the tissue inflammatory response through mediating two of the major stimuli in adhesion formation. PMID:9086414

  1. Ultrastructural immunolocalization of cartilage oligomeric matrix protein (COMP) in relation to collagen fibrils in the equine tendon.

    PubMed

    Södersten, Fredrik; Ekman, Stina; Eloranta, Maija-Leena; Heinegård, Dick; Dudhia, Jayesh; Hultenby, Kjell

    2005-08-01

    The structure and organisation of the extracellular matrix, and in particular the axial alignment of type I collagen fibrils, are essential for the tensile strength of tendons. The resident tenocytes synthesize and maintain the composition of the extracellular matrix, which changes with age and maturation. Other components of the extracellular matrix include less abundant collagen types II, III, V, VI, XII, proteoglycans and glycoproteins. Cartilage oligomeric matrix protein (COMP) is an abundant non-collagenous pentameric glycoprotein in the tendon, which can bind to collagen types I and II. The function of COMP in the tendon is not clear, but it may act as a catalyst in fibrillogenesis. Its concentration changes with age, maturation and load. The present study delineates the ultrastructural distribution of COMP and its correlation to collagen fibril thickness in different compartments in two flexor tendons from horses of different ages (foetus, 8 months, 3 years, 12 years). The immunolabeling for COMP was higher in the superficial digital flexor tendon compared with the deep digital flexor tendon and it increased with the age of the animal, with the highest concentration in the 3-year-olds. Fibril diameter differed between age groups and a more homogenous fibril population was found in the fetal tendons. A positive correlation between high COMP immunolabeling and the percentage of small fibrils (<60 nm) were present in the SDFT. COMP immunolabeling was enriched at the gap region of the collagen fibril. In situ hybridization revealed the strongest expression in tendons from the 3-year-old horses whereas there was no expression in foetal tendon. PMID:16005620

  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. Low stress tendon fatigue is a relatively rapid process in the context of overuse injuries.

    PubMed

    Parent, Gabriel; Huppé, Nicolas; Langelier, Eve

    2011-05-01

    To stimulate healing and prevent tendinosis through optimized physical exercise, it is important to elucidate the tendon response to repetitive mechanical loading. However, the study of this response is challenging due to complex cell-matrix interactions. In an initial approximation, the authors examined tendon mechanical response only, and did not consider cellular activity. The authors investigated the hypothesis that mechanical degradation occurs relatively rapidly (< 24 h) even at very low stress levels. The authors subjected rat tail tendons to mechanical loadings oscillating between 0 and 1.5 MPa up to one of three fatigue levels: 4% strain, 8% strain, or rupture. Using non-destructive mechanical tests, changes in tendon strain and compliance over the entire fatigue testing period were evaluated. Using microscopy techniques, the structural evidence of mechanical degradation was examined. The changes in tendon strain and compliance progressed nonlinearly and accelerated before rupture which took place around the 15-h mark. Histological analyses revealed a higher degree of alteration in the collagen network at increased fatigue levels. At rupture, local zones of damage with low fibril density were evident. These results imply that a repair process must act rapidly at critical sites; otherwise, enzymatic degradation could cause further damage in the manner of a vicious cycle. PMID:21287276

  4. Surgical treatment of ruptures of the Achilles tendon: a review of long-term results.

    PubMed Central

    Krueger-Franke, M; Siebert, C H; Scherzer, S

    1995-01-01

    The rupture of the Achilles tendon is frequently sports-related. In the time from 1 January, 1978 until 31 December, 1988, we treated 358 men and 54 women with such an injury at the Staatliche Orthopaedische Klinik in Munich. The average age of these patients was 43 years. The site of the rupture was generally located between 3-5 cm proximal of the distal insertion of the tendon. In the follow-up examination of 122 patients with surgical treatment of tendo calcaneus ruptures 85% showed 'good' to 'very good' subjective results. Of the operated patients 97% would choose the same treatment under similar circumstances. The isokinetic studies demonstrated a loss of static and dynamic strength in plantar flexion of the ankle joint of 9.1%, and 16.7% respectively, when compared to the healthy contralateral side. The ultrasound examination revealed a thickening of the tendon and of the dorsal paratenon with changes in the internal structure of the injured Achilles tendon. In spite of these favourable results, the high complication rate of 15.1% shows the need for new and extensive studies regarding the various alternative treatment forms, such as functional, non-operative options, to finally resolve the debate about the optimal treatment of Achilles tendon ruptures. Images Figure 4 Figure 5 Figure 6 Figure 7 PMID:7551757

  5. MMP inhibition as a potential method to augment the healing of skeletal muscle and tendon extracellular matrix

    PubMed Central

    Davis, Max E.; Gumucio, Jonathan P.; Sugg, Kristoffer B.; Bedi, Asheesh

    2013-01-01

    The extracellular matrix (ECM) of skeletal muscle and tendon is composed of different types of collagen molecules that play important roles in the transmission of forces throughout the body, and in the repair and regeneration of injured tissues. Fibroblasts are the primary cells in muscle and tendon that maintain, repair, and modify the ECM in response to mechanical loading, injury, and inactivity. Matrix metalloproteinases (MMPs) are enzymes that digest collagen and other structural molecules, which are synthesized and excreted by fibroblasts. MMPs are required for baseline ECM homeostasis, but disruption of MMP regulation due to injury or disease can alter the normal ECM architecture and prevent proper force transmission. Chronic injuries and diseases of muscles and tendons can be severely debilitating, and current therapeutic modalities to enhance healing are quite limited. This review will discuss the mechanobiology of MMPs, and the potential use of MMP inhibitors to improve the treatment of injured and diseased skeletal muscle and tendon tissue. PMID:23640595

  6. Effect of pulley excision on flexor tendon biomechanics.

    PubMed

    Peterson, W W; Manske, P R; Bollinger, B A; Lesker, P A; McCarthy, J A

    1986-01-01

    Flexor tendon function following excision of various portions of the fibro-osseous pulley system was measured biomechanically using a tensile testing machine. The biomechanical parameters measured were tendon excursion (the excursion of the tendon required to fully flex the digit) and work of flexion (the area under the force-excursion curve, representing all the forces that resist tendon flexion). In this experiment, work of flexion included the forces necessary to accomplish full digital flexion against a 15-g counter-weight, as well as the frictional forces that resist tendon gliding. The results indicate that the work of flexion was affected to a greater degree by pulley loss than was tendon excursion, suggesting that it is a more sensitive measurement of tendon function. A2 was found to be the single most important pulley for flexor tendon function, followed by A4. However, both A2 and A4 had to be present if near-normal hand function was to be achieved; sacrificing the A1 pulley was not associated with a significant loss of flexion. The "pulley effect" of the skin and soft tissue as a supplement to the fibro-osseous pulleys in reducing tendon bow-stringing was also noted. Although the parameters of tendon excursion and work of flexion were used in this study to determine the effect of pulley loss on tendon function, they can also be used to evaluate other flexor tendon studies, such as pulley reconstruction. PMID:3950813

  7. 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

  8. Achilles tendon rupture in atypical patient populations.

    PubMed

    Kingsley, Peter

    2016-03-01

    Rupture of the Achilles tendon is a significant injury, and the likelihood of a good recovery is directly associated with early diagnosis and appropriate referral. Such injuries are commonly assessed and identified by practitioners working in 'minors' areas of emergency departments or urgent care settings. The literature frequently describes rupture of the Achilles tendon as 'typically sport-related' affecting 'middle-aged weekend warriors', but this aetiology accounts for only about 70% of such injuries. Factors such as the natural ageing process, obesity and use of some commonly prescribed medications, can increase the risk of developing a tendinopathy and subsequent rupture, often from a seemingly insignificant incident. However, research suggests that injuries in this patient population are more likely be missed on first examination. This article describes risk factors that should alert clinicians to the possibility of Achilles tendon rupture in 'atypical' patient populations. PMID:26948227

  9. Distal biceps tendon reconstruction in chronic ruptures.

    PubMed

    Darlis, Nickolaos A; Sotereanos, Dean G

    2006-01-01

    The purpose of this retrospective study was to evaluate the results of anatomic reattachment with reconstruction of the distal biceps tendon using an Achilles tendon allograft in 7 male patients with chronic distal biceps ruptures. Through a 1-incision anterior approach, the tendon allograft was attached to the bicipital tuberosity by using suture anchors and then secured to the biceps remnant. Follow-up averaged 29 months. Mean elbow flexion was 145 degrees, an extension deficit of 20 degrees was observed in 1 patient, and mean pronosupination was 170 degrees. All patients had 5/5 strength in flexion and supination on manual testing, and all returned to their employment. Mean supination strength was 87% of the contralateral healthy extremity. Six achieved an excellent and 1 a good rating in the Mayo elbow performance score. No complications were encountered. This technique is an excellent alternative to nonanatomic reattachment to the brachialis muscle for patients with high functional demands in pronosupination. PMID:16979059

  10. Flucloxacillin reduces stiffness following flexor tendon repair.

    PubMed

    Schumacher, Hagen H A; James, Nick K

    2008-12-01

    To determine the benefit of antibiotic prophylaxis on postoperative mobility in flexor tendon repairs, case notes of 72 flexor tendon injuries in twenty four patients were analyzed retrospectively (2001-2003). Only patients with non-contaminated injuries from sharp instruments in flexor zone 2 were included in the study; 57% were male, average age was 31 years, and 24% were smokers. The majority of injuries were caused by metal blades (45%). Most tendons were repaired with modified Kessler technique (69%). Twenty-five percent received intravenous flucloxacillin or co-amoxiclav perioperatively. Reduced total active motion (TAM, found in 25% of patients more than 7 weeks after surgical repair) significantly complicated patients without perioperative intravenous flucloxacillin cover. The use of intravenous perioperative flucloxacillin is a plausible adjunct in surgery to prevent postoperatively reduced mobility. PMID:18780024

  11. Tissue engineering and rotator cuff tendon healing.

    PubMed

    Dines, Joshua S; Grande, Daniel A; Dines, David M

    2007-01-01

    Rotator cuff tears are common soft-tissue injuries that often require surgical treatment. Initial efforts to better tendon healing centered on improving the strength of the repair. More recent studies have focused on biologic enhancement of the healing process. Tissue engineering is a multidisciplinary field that involves the application of scientific principles toward creating living tissue to replace, repair, or augment diseased tissue. Gene therapy involves the transfer of a certain gene into a cell so that the cell translates the gene into a specific protein. The advantage of using a gene-therapy, tissue-engineered approach to effect healing rests in the ability of the physician to select growth factors with documented roles in the tendon-healing cascade. Ideally, an improvement to the current repair technique would yield improved tendon healing leading to improved clinical results. PMID:17524676

  12. 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. PMID:22883898

  13. Spontaneous Achilles tendon rupture in alkaptonuria.

    PubMed

    Alajoulin, Omar A; Alsbou, Mohammed S; Ja'afreh, Somayya O; Kalbouneh, Heba M

    2015-12-01

    Alkaptonuria (AKU) is a rare inborn metabolic disease characterized by accumulation of homogentisic acid (HGA). Excretion of HGA in urine causes darkening of urine and its deposition in connective tissues causes dark pigmentation (ochronosis), early degeneration of articular cartilage, weakening of the tendons, and subsequent rupture. In this case report, we present a rare case of a patient presented with unilateral spontaneous rupture of Achilles tendon due to AKU. The patient developed most of the orthopedic manifestations of the disease earlier than typical presentations. Alkaptonuria patients should avoid strenuous exercises and foot straining especially in patients developing early orthopedic manifestations. PMID:26620992

  14. Spontaneous Achilles tendon rupture in alkaptonuria

    PubMed Central

    Alajoulin, Omar A.; Alsbou, Mohammed S.; Ja’afreh, Somayya O.; Kalbouneh, Heba M.

    2015-01-01

    Alkaptonuria (AKU) is a rare inborn metabolic disease characterized by accumulation of homogentisic acid (HGA). Excretion of HGA in urine causes darkening of urine and its deposition in connective tissues causes dark pigmentation (ochronosis), early degeneration of articular cartilage, weakening of the tendons, and subsequent rupture. In this case report, we present a rare case of a patient presented with unilateral spontaneous rupture of Achilles tendon due to AKU. The patient developed most of the orthopedic manifestations of the disease earlier than typical presentations. Alkaptonuria patients should avoid strenuous exercises and foot straining especially in patients developing early orthopedic manifestations. PMID:26620992

  15. Kakapo, a novel cytoskeletal-associated protein is essential for the restricted localization of the neuregulin-like factor, vein, at the muscle-tendon junction site.

    PubMed

    Strumpf, D; Volk, T

    1998-11-30

    In the Drosophila embryo, the correct association of muscles with their specific tendon cells is achieved through reciprocal interactions between these two distinct cell types. Tendon cell differentiation is initiated by activation of the EGF-receptor signaling pathway within these cells by Vein, a neuregulin-like factor secreted by the approaching myotube. Here, we describe the cloning and the molecular and genetic analyses of kakapo, a Drosophila gene, expressed in the tendons, that is essential for muscle-dependent tendon cell differentiation. Kakapo is a large intracellular protein and contains structural domains also found in cytoskeletal-related vertebrate proteins (including plakin, dystrophin, and Gas2 family members). kakapo mutant embryos exhibit abnormal muscle-dependent tendon cell differentiation. A major defect in the kakapo mutant tendon cells is the failure of Vein to be localized at the muscle-tendon junctional site; instead, Vein is dispersed and its levels are reduced. This may lead to aberrant differentiation of tendon cells and consequently to the kakapo mutant deranged somatic muscle phenotype. PMID:9832554

  16. Characterization of fluoroquinolone-induced Achilles tendon toxicity in rats: comparison of toxicities of 10 fluoroquinolones and effects of anti-inflammatory compounds.

    PubMed Central

    Kashida, Y; Kato, M

    1997-01-01

    Fluoroquinolone antibacterial agents have been reported to induce tendon lesions in juvenile rats. In the present study, we characterized fluoroquinolone-induced Achilles tendon lesions by comparing the effects of 10 fluoroquinolones and examining the potential of one of these antimicrobial agents, pefloxacin, to induce tendon lesions when coadministered with one of nine anti-inflammatory compounds. Among the 10 fluoroquinolones tested, fleroxacin and pefloxacin were the most toxic, inducing lesions at a dose of 100 mg/kg of body weight or more, while lomefloxacin, levofloxacin, and ofloxacin or sparfloxacin and enoxacin induced lesions at 300 mg/kg or more and 900 mg/kg, respectively. In contrast, norfloxacin, ciprofloxacin, and tosufloxacin had no effect even at the high dose of 900 mg/kg. The severity of the Achilles tendon lesions appeared to correlate with the structure of the substituent at the seventh position. Furthermore, pefloxacin-induced tendon lesions were inhibited by coadministration with dexamethasone and N-nitro-L-arginine methyl ester. Phenidone (1-phenyl-3-pyrazolidinone) and 2-(12-hydroxydodeca-5,10-diynyl)3,5,6-trimethyl-1,4-benzoqui none (AA861) also decreased the incidence of tendon lesions. In contrast, catalase, dimethyl sulfoxide, indomethacin, pyrilamine, and cimetidine did not modify these tendon lesions. These results suggest that nitric oxide and 5-lipoxigenase products partly mediate fluoroquinolone-induced tendon lesions. PMID:9371338

  17. Proximal coracobrachialis tendon rupture, subscapularis tendon rupture, and medial dislocation of the long head of the biceps tendon in an adult after traumatic anterior shoulder dislocation

    PubMed Central

    Saltzman, Bryan M.; Harris, Joshua D.; Forsythe, Brian

    2015-01-01

    Rupture of the coracobrachialis is a rare entity, in isolation or in combination with other muscular or tendinous structures. When described, it is often a result of direct trauma to the anatomic area resulting in rupture of the muscle belly. The authors present a case of a 57-year-old female who suffered a proximal coracobrachialis tendon rupture from its origin at the coracoid process, with concomitant subscapularis tear and medial dislocation of the long head of biceps tendon after first time traumatic anterior shoulder dislocation. Two weeks after injury, magnetic resonance imaging suggested the diagnosis, which was confirmed during combined arthroscopic and open technique. Soft-tissue tenodesis of coracobrachialis to the intact short head of the biceps, tenodesis of the long head of biceps to the intertubercular groove, and double-row anatomic repair of the subscapularis were performed. The patient did well postoperatively, and ultimately at 6 months follow-up, she was without pain, and obtained 160° of active forward elevation, 45° of external rotation, internal rotation to T8, 5/5 subscapularis and biceps strength. Scoring scales had improved from the following preoperative to final follow-up: American Shoulder and Elbow Surgeons, 53.33-98.33; constant, 10-100; visual analogue scale-pain, 4-0. DASH score was 5. PMID:25937715

  18. Spontaneous "spaghetti" flexor tendon ruptures in the rheumatoid wrist.

    PubMed

    Hashizume, Hiroyuki; Nishida, Keiichiro; Fujiwara, Kazuo; Inoue, Hajime

    2004-01-01

    A 54-year-old woman who had been treated for rheumatoid arthritis for 12 years developed spontaneous multiple flexor tendon ruptures during a 5-month period. Radiography revealed volar subluxation of the lunate bone. Surgery was performed 5 months after the first onset of tendon rupture. All eight flexors, except the flexor pollicis longus tendons, had ruptured, and the damage resembled spaghetti. Four flexor digitorum profundus tendons were reconstructed by bridge graft using their respective sublimis tendons. Wrist joint fusion and tenolysis were performed 3 months after the first operation. Each finger achieved a good range of motion 2 years and 6 months after the second operation. PMID:17143686

  19. [Primary treatment of complicated flexor tendon injuries of the hand].

    PubMed

    Lotter, O; Vogel, D; Stahl, S; Pfau, M; Schaller, H-E

    2011-06-01

    Complicated flexor tendon injuries are classified into lacerations, avulsions, ruptures, and defects. They are often a challenge for hand surgeons and frequently they present unsatisfactory functional results postoperatively. Lacerations and avulsions are usually treated by pull-out sutures and suture anchors. In ruptures, the causality should be sought. Tendon-linking, transposition and tenodesis/arthrodesis are the domain of rheumatoid arthritis. The primary transplantation of tendons is rarely indicated, ideally in non-contaminated flexor tendon defects in zones III-V with an uninjured surrounding soft tissue situation. Postoperative rehabilitation programs are very the same as in normal flexor tendon injuries. PMID:21660511

  20. Combined Tendon and Bone Allograft Transplantation for Chronic Achilles Tendon Ruptures.

    PubMed

    Catanzariti, Alan R; Hentges, Matthew

    2016-01-01

    Combined flexor hallucis longus tendon transfer and bone-tendon allograft transplantation is a reasonable option for advanced distal-segment Achilles tendinopathy. This procedure provides anatomic restoration and improved function of the posterior muscle group without sacrificing the regional anatomy. Allograft transplantation is safe and does not require immunosuppressive therapy. The soft tissue envelope should be healthy because wound complications can be an issue. This procedure is especially helpful in patients with significant disability. PMID:26590730

  1. Effect of hydrogen peroxide on human tendon allograft.

    PubMed

    Gardner, E M H; VonderHeide, N; Fisher, R; Brooker, G; Yates, P J

    2013-12-01

    Bacterial contamination of tendon allografts at the completion of processing has historically been about 2 %, with tendons that are found to be culture positive being discarded. Treatment of tendon allograft with hydrogen peroxide at the beginning of tissue processing may reduce bacterial contamination, however, the potential side effects of hydrogen peroxide treatment include hydrolysis of the collagen and this may alter the mechanical properties of the graft. Pairs of human tendons were used. One was washed in 3 % hydrogen peroxide for 5 min and the untreated tendon was used as a control. The ultimate tensile strength of the tendons was determined using a material testing machine. A freeze clamp technique was used to hold the tendons securely at the high loads required to cause tendon failure. There was no statistical difference in the ultimate tensile strength between the treated and untreated tendons. Mean strength ranged from Extensor Hallucis Longus at 588 Newtons to Tibialis Posterior at 2,366 Newtons. Hydrogen peroxide washing may reduce bacterial contamination of tendon allograft and does not affect the strength of the tendon. PMID:23681552

  2. High-resolution MRI assessment of dactylitis in psoriatic arthritis shows flexor tendon pulley and sheath-related enthesitis

    PubMed Central

    Tan, Ai Lyn; Fukuba, Eiji; Halliday, Nicola Ann; Tanner, Steven F; Emery, Paul; McGonagle, Dennis

    2015-01-01

    Objective Dactylitis is a hallmark of psoriatic arthritis (PsA) where flexor tenosynovitis is common. This study explored the microanatomical basis of dactylitis using high-resolution MRI (hrMRI) to visualise the small entheses around the digits. Methods Twelve patients with psoriatic dactylitis (4 fingers, 8 toes), and 10 healthy volunteers (6 fingers, 4 toes) had hrMRI of the digits using a ‘microscopy’ coil and contrast enhancement. All structures were evaluated including the tendons and ligaments, related enthesis organs, pulleys, volar/plantar plates and tendon sheaths. Results In dactylitis, collateral ligament enthesitis was seen in nine digits (75%), extensor tendon enthesitis in six digits (50%), functional enthesitis (5 digits, 42%), abnormal enhancement at the volar plates (2/5 joints, 40%) and the plantar plate (1/5 joints, 20%). Nine cases (75%) demonstrated flexor tenosynovitis, with flexor tendon pulley/flexor sheath microenthesopathy observed in 50% of all cases. Less abnormalities which were milder was observed in the normal controls, none of whom had any signal changes in the tendon pulleys or fibrous sheaths. Conclusions This study provides proof of concept for a link between dactylitis and ‘digital polyenthesitis’ including disease of the miniature enthesis pulleys of the flexor tendons, further affirming the concept of enthesitis in PsA. PMID:25261575

  3. Anatomy of the sural nerve in a computer?assisted model: implications for surgical minimal?invasive Achilles tendon repair

    PubMed Central

    Citak, Musa; Knobloch, Karsten; Albrecht, Knut; Krettek, Christian; Hufner, Tobias

    2007-01-01

    Background Sural nerve injuries are an evident risk especially of minimal?invasive surgical Achilles tendon repair. However, detailed anatomical studies focusing on the relationship of the sural nerve with the Achilles tendon at various levels are scarce, even pending in two planes. Aim To determine the position and course of the sural nerve in relation to the Achilles tendon in two planes after trans?section and computer?assisted determination. Methods The exact course of the sural nerve was determined in 10 cadavers (55.3?years, 19–89?years), using a computer?assisted method in two planes (transversal/sagittal). Results The sural nerve crossed the Achilles tendon at 11 (8.7–12.4)?cm proximal to the tuber calcanei. The distance between the lateral crossing and the proximal musculotendineus junction was 35 (20–58)?mm. Starting from the tuber calcanei, the distance was 2/2?mm (transversal/sagittal plane) at 11?cm proximal to the tuber calcanei, 4/4?mm at 10?cm proximal, 5/6?mm at 9?cm, 8/10?mm at 5?cm and 11/18?mm at the tuber calcanei. Conclusion In the lateral crossing region of the sural nerve and the lateral proximal Achilles tendon 9–12?cm proximal to the tuber calcanei, a close relationship of both anatomical structures can be visualised using computer?assisted measurements; caution is suggested to prevent sural nerve entrapment in either open or percutaneous Achilles tendon repair. PMID:17347315

  4. Spondylodiscitis and Achilles tendonitis due to gout.

    PubMed

    Taniguchi, Yoshinori; Matsumoto, Tatsuki; Tsugita, Makoto; Fujimoto, Shimpei; Terada, Yoshio

    2014-11-01

    The patient, a 62-year-old man with a 3-year history of hyperuricemia, presented with severe neck pain, Achilles enthesopathy and polyarthralgia. He consumed alcohol heavily. The biochemical profile was normal except for elevated levels of CRP (3.6 mg/dl; normal < 0.3), uric acid (UA) (10.9 mg/dl; normal 2.5-7.5) and creatinine (1.7 mg/dl; normal 0.5-1.0). Bone scintigraphy showed polyarthritis at the right elbow, wrist and bilateral first MTP joints. Notably, bone scintigraphy with computed tomography also revealed spondylodiscitis of C5-C6, which was confirmed by MRI, and left Achilles tendonitis. Moreover, left Achilles tendonitis was also confirmed by ultrasonography, indicating enthesitis with low-echoic lesion and calcification. Needle aspiration yielded a white viscous liquid, with numerous urate crystals identified on polarized light microscopy. He was diagnosed with gouty arthritis associated with spondylodiscitis and Achilles tendonitis. After the treatment with allopurinol, colchicine and predonisolone, his symptoms were improved, and serum CRP and UA levels were normalized. The cervical spine and Achilles tendon are rare and notable sites of involvements in gout, and differential diagnosis of gouty arthritis from spondyloarthritis, rheumatoid arthritis, tumor, pseudogout, and infection is necessary. When the patient was noted to have neck pain and Achilles enthesopathy, we should always recognize gouty arthritis. PMID:24498865

  5. How tendons buffer energy dissipation by muscle

    PubMed Central

    Roberts, Thomas J.; Konow, Nicolai

    2013-01-01

    To decelerate the body and limbs, muscles actively lengthen to dissipate energy. During rapid energy-dissipating events, tendons buffer the work done on muscle by temporarily storing elastic energy, then releasing this energy to do work on the muscle. This elastic mechanism may reduce the risk of muscle damage by reducing peak forces and lengthening rates of active muscle. PMID:23873133

  6. Tendon fatigue in response to mechanical loading.

    PubMed

    Andarawis-Puri, N; Flatow, E L

    2011-06-01

    Tendinopathies are commonly attributable to accumulation of sub-rupture fatigue damage from repetitive use. Data is limited to late stage disease from patients undergoing surgery, motivating development of animal models, such as ones utilizing treadmill running or repetitive reaching, to investigate the progression of tendinopathies. We developed an in vivo model using the rat patellar tendon that allows control of the loading directly applied to the tendon. This manuscript discusses the response of tendons to fatigue loading and applications of our model. Briefly, the fatigue life of the tendon was used to define low, moderate and high levels of fatigue loading. Morphological assessment showed a progression from mild kinks to fiber disruption, for low to high level fatigue loading. Collagen expression, 1 and 3 days post loading, showed more modest changes for low and moderate than high level fatigue loading. Protein and mRNA expression of Ineterleukin-1? and MMP-13 were upregulated for moderate but not low level fatigue loading. Moderate level (7200 cycles) and 100 cycles of fatigue loading resulted in a catabolic and anabolic molecular profile respectively, at both 1 and 7 days post loading. Results suggest unique mechanisms for different levels of fatigue loading that are distinct from laceration. PMID:21625047

  7. Engaging Stem Cells for Customized Tendon Regeneration

    PubMed Central

    Thaker, Hatim; Sharma, Arun K.

    2012-01-01

    The need for a consistent therapeutic approach to tendon injury repair is long overdue. Patients with tendon microtears or full ruptures are eligible for a wide range of invasive and non invasive interventions, often subjectively decided by the physician. Surgery produces the best outcomes, and while studies have been conducted to optimize graft constructs and to track outcomes, the data from these studies have been inconclusive on the whole. What has been established is a clear understanding of healthy tendon architecture and the inherent process of healing. With this knowledge, tissue regeneration efforts have achieved immense progress in scaffold design, cell line selection, and, more recently, the appropriate use of cytokines and growth factors. This paper evaluates the plasticity of bone-marrow-derived stem cells and the elasticity of recently developed biomaterials towards tendon regeneration efforts. Mesenchymal stem cells (MSCs), hematopoietic progenitor cells, and poly(1,8-octanediol co-citrate) scaffolds (POC) are discussed in the context of established grafting strategies. With POC scaffolds to cradle the growth of MSCs and hematopoietic progenitor cells, developing a fibroelastic network guided by cytokines and growth factors may contribute towards consistent graft constructs, enhanced functionality, and better patient outcomes. PMID:22685473

  8. Minimally Invasive Approach to Achilles Tendon Pathology.

    PubMed

    Hegewald, Kenneth W; Doyle, Matthew D; Todd, Nicholas W; Rush, Shannon M

    2016-01-01

    Many surgical procedures have been described for Achilles tendon pathology; however, no overwhelming consensus has been reached for surgical treatment. Open repair using a central or paramedian incision allows excellent visualization for end-to-end anastomosis in the case of a complete rupture and detachment and reattachment for insertional pathologies. Postoperative wound dehiscence and infection in the Achilles tendon have considerable deleterious effects on overall functional recovery and outcome and sometimes require plastic surgery techniques to achieve coverage. With the aim of avoiding such complications, foot and ankle surgeons have studied less invasive techniques for repair. We describe a percutaneous approach to Achilles tendinopathy using a modification of the Bunnell suture weave technique combined with the use of interference screws. No direct end-to-end repair of the tendon is performed, rather, the proximal stump is brought in direct proximity of the distal stump, preventing overlengthening and proximal stump retraction. This technique also reduces the suture creep often seen with end-to-end tendon repair by providing a direct, rigid suture to bone interface. We have used the new technique to minimize dissection and exposure while restoring function and accelerating recovery postoperatively. PMID:26385574

  9. Human Leg Model Predicts Ankle Muscle-Tendon Morphology, State, Roles and Energetics in Walking

    PubMed Central

    Krishnaswamy, Pavitra; Brown, Emery N.; Herr, Hugh M.

    2011-01-01

    A common feature in biological neuromuscular systems is the redundancy in joint actuation. Understanding how these redundancies are resolved in typical joint movements has been a long-standing problem in biomechanics, neuroscience and prosthetics. Many empirical studies have uncovered neural, mechanical and energetic aspects of how humans resolve these degrees of freedom to actuate leg joints for common tasks like walking. However, a unifying theoretical framework that explains the many independent empirical observations and predicts individual muscle and tendon contributions to joint actuation is yet to be established. Here we develop a computational framework to address how the ankle joint actuation problem is resolved by the neuromuscular system in walking. Our framework is founded upon the proposal that a consideration of both neural control and leg muscle-tendon morphology is critical to obtain predictive, mechanistic insight into individual muscle and tendon contributions to joint actuation. We examine kinetic, kinematic and electromyographic data from healthy walking subjects to find that human leg muscle-tendon morphology and neural activations enable a metabolically optimal realization of biological ankle mechanics in walking. This optimal realization (a) corresponds to independent empirical observations of operation and performance of the soleus and gastrocnemius muscles, (b) gives rise to an efficient load-sharing amongst ankle muscle-tendon units and (c) causes soleus and gastrocnemius muscle fibers to take on distinct mechanical roles of force generation and power production at the end of stance phase in walking. The framework outlined here suggests that the dynamical interplay between leg structure and neural control may be key to the high walking economy of humans, and has implications as a means to obtain insight into empirically inaccessible features of individual muscle and tendons in biomechanical tasks. PMID:21445231

  10. Model for assessment of mobility of toes and healing of tendons in rabbits.

    PubMed

    Olmarker, Kjell; Ekström, Lars; Håkansson, Joakim; Nilsson, Elin; Wiig, Monica; Mahlapuu, Margit

    2010-12-01

    Repair of a transected flexor tendon will, despite careful technique and early rehabilitation, usually result in a restricted range of movement. This is mainly because adhesions form between the tendon and the surrounding structures. Our aim was to establish an experimental model in rabbits for future studies on new techniques to reduce the formation of adhesions after zone II repair of flexor tendons. In rabbits' hind paws the metatarsal bones II, IV, and V were removed and the flexor tendon was freed to the metatarsophalangeal (MTP) joint. The digits were secured in a specifically-designed biomechanical testing device comprising a servo-hydraulic actuator that was designed to apply controlled force or displacement. The tests were videotaped with a digital force-monitor behind the tested digit. Paper printouts from the recordings were obtained for 0, 0.5, 1, 2, 3, 4, and 5 Newton (N) and metatarsophalangeal, proximal interphalangeal, and distal interphalangeal, angles and distances between metatarsophalangeal joints and claws were measured. The tensile strength of the tendon was evaluated by a load-to-failure test. The continuous data obtained from the experiments were used to calculate functional stiffness at the selected forces. The model allows for unique continuous recordings of mobility of toes, thereby indirectly quantifying the presence of adhesions and the assessment of tensile strength. The data are reproducible, and there is little variation between the digits tested. The model is primarily intended to compare data among treated and non-treated digits of methods to limit the formation of adhesions after tendons have been repaired. PMID:21446803

  11. 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

  12. Ultrasound of the elbow with emphasis on detailed assessment of ligaments, tendons, and nerves.

    PubMed

    De Maeseneer, Michel; Brigido, Monica Kalume; Antic, Marijana; Lenchik, Leon; Milants, Annemieke; Vereecke, Evie; Jager, Tjeerd; Shahabpour, Maryam

    2015-04-01

    The high resolution and dynamic capability of ultrasound make it an excellent tool for assessment of superficial structures. The ligaments, tendons, and nerves about the elbow can be fully evaluated with ultrasound. The medial collateral ligament consists of an anterior and posterior band that can easily be identified. The lateral ligament complex consists of the radial collateral ligament, ulnar insertion of the annular ligament, and lateral ulnar collateral ligament, easily identified with specialized probe positioning. The lateral ulnar collateral ligament can best be seen in the cobra position. On ultrasound medial elbow tendons can be followed nearly up to their common insertion. The pronator teres, flexor carpi radialis, palmaris longus, and flexor digitorum superficialis can be identified. The laterally located brachioradialis and extensor carpi radialis longus insert on the supracondylar ridge. The other lateral tendons can be followed up to their common insertion on the lateral epicondyle. The extensor digitorum, extensor carpi radialis brevis, extensor digiti minimi, and extensor carpi ulnaris can be differentiated. The distal biceps tendon is commonly bifid. For a complete assessment of the distal biceps tendon specialized views are necessary. These include an anterior axial approach, medial and lateral approach, and cobra position. In the cubital tunnel the ulnar nerve is covered by the ligament of Osborne. Slightly more distally the ulnar nerve courses between the two heads of the flexor carpi ulnaris. An accessory muscle, the anconeus epitrochlearis can cover the ulnar nerve at the cubital tunnel, and is easily identified on ultrasound. The radial nerve divides in a superficial sensory branch and a deep motor branch. The motor branch, the posterior interosseous nerve, courses under the arcade of Frohse where it enters the supinator muscle. At the level of the dorsal wrist the posterior interosseous nerve is located at the deep aspect of the extensor tendons. The median nerve may be compressed at various sites, including the lacertus fibrosis, between the pronator teres heads, and the sublimis bridge. These compression sites can be identified with ultrasound. PMID:25638576

  13. Immunolocalization of collagens (I and III) and cartilage oligomeric matrix protein in the normal and injured equine superficial digital flexor tendon.

    PubMed

    Södersten, Fredrik; Hultenby, Kjell; Heinegård, Dick; Johnston, Christopher; Ekman, Stina

    2013-01-01

    This is a descriptive study of tendon pathology with different structural appearances of repair tissue correlated to immunolocalization of cartilage oligomeric matrix protein (COMP) and type I and III collagens and expression of COMP mRNA. The material consists of nine tendons from seven horses (5-25 years old; mean age of 10 years) with clinical tendinopathy and three normal tendons from horses (3, 3, and 13 years old) euthanized for non-orthopedic reasons. The injured tendons displayed different repair-tissue appearances with organized and disorganized fibroblastic regions as well as areas of necrosis. The normal tendons presented distinct immunoreactivity for COMP and expression of COMP mRNA and type I collagen in the normal aligned fiber structures, but no immunolabeling of type III collagen. However, immunoreactivity for type III collagen was present in the endotenon surrounding the fiber bundles, where no expression of COMP could be seen. Immunostaining for type I and III collagens was present in all of the pathologic regions indicating repair tissue. Interestingly, the granulation tissues showed immunostaining for COMP and expression of COMP mRNA, indicating a role for COMP in repair and remodeling of the tendon after fiber degeneration and rupture. The present results suggest that not only type III collagen but also COMP is involved in the repair and remodeling processes of the tendon. PMID:23020676

  14. 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

  15. 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

  16. Indirect Co-Culture with Tendons or Tenocytes Can Program Amniotic Epithelial Cells towards Stepwise Tenogenic Differentiation

    PubMed Central

    Barboni, Barbara; Curini, Valentina; Russo, Valentina; Mauro, Annunziata; Di Giacinto, Oriana; Marchisio, Marco; Alfonsi, Melissa; Mattioli, Mauro

    2012-01-01

    Background Amniotic epithelial cells (AEC) have potential applications in cell-based therapy. Thus far their ability to differentiate into tenocytes has not been investigated although a cell source providing a large supply of tenocytes remains a priority target of regenerative medicine in order to respond to the poor self-repair capability of adult tendons. Starting from this premise, the present research has been designed firstly to verify whether the co-culture with adult primary tenocytes could be exploited in order to induce tenogenic differentiation in AEC, as previously demonstrated in mesenchymal stem cells. Since the co-culture systems inducing cell differentiation takes advantage of specific soluble paracrine factors released by tenocytes, the research has been then addressed to study whether the co-culture could be improved by making use of the different cell populations present within tendon explants or of the high regenerative properties of fetal derived cell/tissue. Methodology/Principal Findings Freshly isolated AEC, obtained from ovine fetuses at mid-gestation, were co-incubated with explanted tendons or primary tenocytes obtained from fetal or adult calcaneal tendons. The morphological and functional analysis indicated that AEC possessed tenogenic differentiation potential. However, only AEC exposed to fetal-derived cell/tissues developed in vitro tendon-like three dimensional structures with an expression profile of matrix (COL1 and THSB4) and mesenchymal/tendon related genes (TNM, OCN and SCXB) similar to that recorded in native ovine tendons. The tendon-like structures displayed high levels of organization as documented by the cell morphology, the newly deposited matrix enriched in COL1 and widespread expression of gap junction proteins (Connexin 32 and 43). Conclusions/Significance The co-culture system improves its efficiency in promoting AEC differentiation by exploiting the inductive tenogenic soluble factors released by fetal tendon cells or explants. The co-cultural system can be proposed as a low cost and easy technique to engineer tendon for biological study and cell therapy approach. PMID:22348033

  17. 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

  18. 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. XXXX addresses some of the limitations present in the prior art approaches noted above. The grasp assist device includes a glove and a sleeve, which may be worn on a respective hand and forearm of an operator. Linear actuators supported within the sleeve provide tension to flexible tendons, which in turn are connected to the fingers and/or thumb of a glove. The selective tensioning of the tendons improves the operator's grasp strength, and may also facilitate rehabilitation from an injury. It is recognized herein that existing tendon-driven grasp assist devices have certain performance limitations. For example, some designs may require actuator over sizing in order to provide a sufficient amount of actuator travel for applying necessary amounts of tension to a given tendon, e.g., to fully close a finger of a hand wearing the glove into a desired grasp pose. Substantial increases in both size and

  19. Collagenolytic activity is produced by rabbit ligaments and tendon

    SciTech Connect

    Harper, J.; Amiel, D.; Harper, E.

    1986-05-01

    The authors examined the patellar tendon (PT), anterior cruciate ligament (ACL) and medial collateral ligament (MCL) from normal rabbits for collagenase activity. All three connective tissues contain large amounts of collagen and the catabolism of this structural protein is important to their integrity. The authors cultured each tissue in serum free medium for 14 days. Collagenase was produced by all three connective tissues after a lag period of up to 7 days, as detected by the /sup 14/C-glycine peptide-release assay. Culture media that did not express enzyme the authors found to contain inhibitory activity. The collagenases and inhibitors from each tissue have been quantitated and characterized. After 9 days the collagenase activity for the rabbit periarticular tissues was 6.1 (PT), 4.4 (MCL) and 8.6 (ACL) units per milligram of secreted protein. The cleavage site of all three collagenases was found to be similar to that observed for rabbit skin collagenase, and generation of reaction products TC/sup A/ and TC/sup B/ was demonstrated by collagenases from PT, MCL and ACL. These results suggest that the metabolism of ligaments and tendon is regulated by the production of zymogen, active collagenase and inhibitor, similar to other connective tissues. The role of these components in joint injury and joint diseases is currently being investigated.

  20. 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. PMID:25902929

  1. A Tendon Cell Specific RNAi Screen Reveals Novel Candidates Essential for Muscle Tendon Interaction

    PubMed Central

    Tiwari, Prabhat; Malhotra, Vivek; VijayRaghavan, K.

    2015-01-01

    Tendons are fibrous connective tissue which connect muscles to the skeletal elements thus acting as passive transmitters of force during locomotion and provide appropriate body posture. Tendon-derived cues, albeit poorly understood, are necessary for proper muscle guidance and attachment during development. In the present study, we used dorsal longitudinal muscles of Drosophila and their tendon attachment sites to unravel the molecular nature of interactions between muscles and tendons. We performed a genetic screen using RNAi-mediated knockdown in tendon cells to find out molecular players involved in the formation and maintenance of myotendinous junction and found 21 candidates out of 2507 RNAi lines screened. Of these, 19 were novel molecules in context of myotendinous system. Integrin-βPS and Talin, picked as candidates in this screen, are known to play important role in the cell-cell interaction and myotendinous junction formation validating our screen. We have found candidates with enzymatic function, transcription activity, cell adhesion, protein folding and intracellular transport function. Tango1, an ER exit protein involved in collagen secretion was identified as a candidate molecule involved in the formation of myotendinous junction. Tango1 knockdown was found to affect development of muscle attachment sites and formation of myotendinous junction. Tango1 was also found to be involved in secretion of Viking (Collagen type IV) and BM-40 from hemocytes and fat cells. PMID:26488612

  2. A ganglion of the patellar tendon in patellar tendon-lateral femoral condyle friction syndrome.

    PubMed

    Touraine, Sébastien; Lagadec, Matthieu; Petrover, David; Genah, Idan; Parlier-Cuau, Caroline; Bousson, Valérie; Laredo, Jean-Denis

    2013-09-01

    Intratendinous ganglia are rare. We report the case of a sedentary woman with chronic mechanical anterolateral pain of the knee and an extensive ganglion of the patellar tendon as indicated on magnetic resonance (MR) and ultrasound (US) examinations. There was evidence of a high-riding patella, patellar malalignment and patellar tendon-lateral femoral condyle friction syndrome with significantly close contact between the patellar tendon and the lateral facet of the femoral trochlea. The ultrasound-guided aspiration of the ganglion enabled a localized injection of an anti-inflammatory drug (cortivazol) and the cytopathological examination of the fluid, which confirmed the diagnosis. Clinical improvement was maintained with knee rehabilitation and was satisfactory at follow-up after 1 year. To our knowledge, we report the first case of a ganglion of the patellar tendon subsequent to patellar tendon-lateral femoral condyle friction syndrome. We found that this case was illustrative of mucoid degeneration in connective tissue due to chronic repetitive microtraumas. Additionally, this case provided the opportunity to discuss the management of this condition in a sedentary individual with a high-riding patella and patellar malalignment. PMID:23657611

  3. Patellar tendon ossification after anterior cruciate ligament reconstruction using bone – patellar tendon – bone autograft

    PubMed Central

    2013-01-01

    Background Among the various complications described in literature, the patellar tendon ossification is an uncommon occurrence in anterior cruciate ligament (ACL) reconstruction using bone – patellar tendon – bone graft (BPTB). The heterotopic ossification is linked to knee traumatism, intramedullary nailing of the tibia and after partial patellectomy, but only two cases of this event linked to ACL surgery have been reported in literature. Case presentation We present a case of a 42-year-old Caucasian man affected by symptomatic extended heterotopic ossification of patellar tendon after 20 months from ACL reconstruction using BPTB. The clinical diagnosis was confirmed by Ultrasound, X-Ray and Computed Tomography studies, blood tests were performed to exclude metabolic diseases then the surgical removal of the lesion was performed. After three years from surgery, the patient did not report femoro-patellar pain, there was not range of motion limitation and the clinical-radiological examinations resulted negative. Conclusion The surgical removal of the ossifications followed by anti-inflammatory therapy, seems to be useful in order to relieve pain and to prevent relapses. Moreover, a thorough cleaning of the patellar tendon may reveal useful, in order to prevent bone fragments remain inside it and to reduce patellar tendon heterotopic ossification risk. PMID:23663528

  4. Probabilistic model of ligaments and tendons: Quasistatic linear stretching

    NASA Astrophysics Data System (ADS)

    Bontempi, M.

    2009-03-01

    Ligaments and tendons have a significant role in the musculoskeletal system and are frequently subjected to injury. This study presents a model of collagen fibers, based on the study of a statistical distribution of fibers when they are subjected to quasistatic linear stretching. With respect to other methodologies, this model is able to describe the behavior of the bundle using less ad hoc hypotheses and is able to describe all the quasistatic stretch-load responses of the bundle, including the yield and failure regions described in the literature. It has two other important results: the first is that it is able to correlate the mechanical behavior of the bundle with its internal structure, and it suggests a methodology to deduce the fibers population distribution directly from the tensile-test data. The second is that it can follow fibers’ structure evolution during the stretching and it is possible to study the internal adaptation of fibers in physiological and pathological conditions.

  5. [Animal experiment study of healing of the sutured flexor tendon].

    PubMed

    Martini, A K; Blimke, B

    1992-01-01

    The purpose of the present study was to determine whether tendons contain intrinsic cells capable of repair. To accomplish this, rabbit flexor tendons were exposed microsurgically, cut through, resutured and transferred as free transplant into the knee-joint. Immobilisation of the knee-joint will cause progressive formation of adhesions permitting neovascularisation of the transplant. Both is not observed when sutured flexor tendons were put in a knee articulation with full range of joint motion. Transmission electron micrography revealed up to 8 weeks after implantation vital cells and incidences of collagen neosynthesis independently whether adhesions existed or not. Histologically intrinsic repair was confirmed in mobile transplants and mainly initiated by cells of the visceral synovial sheet which form an anatomic-surgical unity with the tendon. In conclusion the importance of the synovial fluid for the tendon nutrition is underlined by the fact that an intrinsic healing of flexor tendon is possible without formation of adhesions. PMID:1582849

  6. 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

  7. Anterior cruciate ligament reconstruction with allograft tendons.

    PubMed

    Strickland, Sabrina M; MacGillivray, John D; Warren, Russell F

    2003-01-01

    Allograft tissue allows reconstruction of the ACL without the donor site morbidity that can be caused by autograft harvesting. Patients who must kneel as a part of their occupation or chosen sport are particularly good candidates for allograft reconstruction. Patients over 45 years of age and those requiring revision ACL surgery can also benefit from the use and availability of allograft tendons. In some cases, patients or surgeons may opt for allograft tendons to maximize the result or morbidity ratio. Despite advances in cadaver screening and graft preparation, there remain risks of disease transmission and joint infection after allograft implantation. Detailed explanation and informed consent is vitally important in cases in which allograft tissue is used. PMID:12735200

  8. An efficient robotic tendon for gait assistance.

    PubMed

    Hollander, Kevin W; Ilg, Robert; Sugar, Thomas G; Herring, Donald

    2006-10-01

    A robotic tendon is a spring based, linear actuator in which the stiffness of the spring is crucial for its successful use in a lightweight, energy efficient, powered ankle orthosis. Like its human analog, the robotic tendon uses its inherent elastic nature to reduce both peak power and energy requirements for its motor. In the ideal example, peak power required of the motor for ankle gait is reduced from 250 W to just 77 W. In addition, ideal energy requirements are reduced from nearly 36 J to just 21 J. Using this approach, an initial prototype has provided 100% of the power and energy necessary for ankle gait in a compact 0.95 kg package, seven times less than an equivalent motor/gearbox system. PMID:16995768

  9. 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. PMID:24231817

  10. Rupture of the quadriceps tendon. A case report in a young dog.

    PubMed

    Arnault, F; Dembour, T; Gallois Bride, H; Chancrin, J L

    2009-01-01

    A five-month-old, male, 16 kg, mixed breed dog was presented for an acute non-weight bearing lameness of the right hind limb. A subtotal avulsion of the quadriceps tendon at its patellar insertion was diagnosed through radiography and ultrasonography. Two nylon sutures secured with a stainless steel crimp were placed in a locking loop pattern in the quadriceps tendon and through a transverse 2.7 mm drill-hole in the patella. No external coaptation was used postoperatively. A full functional recovery was observed, and was followed for one year postoperatively. Quadriceps tendon rupture has not been described in the veterinary literature to our knowledge; in humans, quadriceps tendon rupture is a well known entity, often due to systemic disease resulting in weakening of the tendinous structures. In the case presented herein, the dog's history, young age and location, without underlying biochemical abnormalities, led us to believe that the observed lesion was of traumatic origin. The surgical treatment performed was based on that performed in humans and also that which has been investigated experimentally in the dog. PMID:19151876

  11. Interfibrillar shear stress is the loading mechanism of collagen fibrils in tendon

    PubMed Central

    Szczesny, Spencer E.; Elliott, Dawn M.

    2014-01-01

    Despite the critical role tendons play in transmitting loads throughout the musculoskeletal system, little is known about the microstructural mechanisms underlying their mechanical function. Of particular interest is whether collagen fibrils in tendon fascicles bear load independently or if load is transferred between fibrils through interfibrillar shear forces. We conducted multiscale experimental testing and developed a microstructural shear lag model to explicitly test whether interfibrillar shear load transfer is indeed the fibrillar loading mechanism in tendon. Experimental correlations between fascicle macroscale mechanics and microscale interfibrillar sliding suggest that fibrils are discontinuous and share load. Moreover, for the first time, we demonstrate that a shear lag model can replicate the fascicle macroscale mechanics as well as predict the microscale fibrillar deformations. Since interfibrillar shear stress is the fundamental loading mechanism assumed in the model, this result provides strong evidence that load is transferred between fibrils in tendon and possibly other aligned collagenous tissues. Conclusively establishing this fibrillar loading mechanism and identifying the involved structural components should help develop repair strategies for tissue degeneration and guide the design of tissue engineered replacements. PMID:24530560

  12. Engineering tendon and ligament tissues: present developments towards successful clinical products.

    PubMed

    Rodrigues, Márcia T; Reis, Rui L; Gomes, Manuela E

    2013-09-01

    Musculoskeletal diseases are one of the leading causes of disability worldwide. Among them, tendon and ligament injuries represent an important aspect to consider in both athletes and active working people. Tendon and ligament damage is an important cause of joint instability, and progresses into early onset of osteoarthritis, pain, disability and eventually the need for joint replacement surgery. The social and economical burden associated with these medical conditions presents a compelling argument for greater understanding and expanding research on this issue. The particular physiology of tendons and ligaments (avascular, hypocellular and overall structural mechanical features) makes it difficult for currently available treatments to reach a complete and long-term functional repair of the damaged tissue, especially when complete tear occurs. Despite the effort, the treatment modalities for tendon and ligament are suboptimal, which have led to the development of alternative therapies, such as the delivery of growth factors, development of engineered scaffolds or the application of stem cells, which have been approached in this review. PMID:22499564

  13. Quadriceps Tendon Rupture due to Postepileptic Convulsion

    PubMed Central

    Erkut, Adem; Guvercin, Yilmaz; Sahin, Rifat; Keskin, Davut

    2014-01-01

    We present a case of quadriceps tendon (QT) rupture. QT ruptures can occur in all ages. The cause is mostly traumatic in origin. Spontaneous ruptures that are thought to result from predisposing conditions are rare. Post-convulsion QT ruptures lacking traumas in their history can be overlooked in clinical examinations. This should be born in mind by the attending physician, as early diagnosis and treatment of the condition can lead to satisfactory outcomes. PMID:24944977

  14. Arthroscopically assisted Z-lengthening of extensor hallucis longus tendon.

    PubMed

    Lui, T H

    2007-11-01

    Extensor hallucis longus tendon contracture can lead to hyperextension deformity of the big toe. We describe an endoscopic approach of Z-lengthening of the tendon. Extensor hallucis longus tendoscopy is performed with a distal portal at the level of the metatarsal neck and a proximal portal at the level of the navicular. At the distal portal, the medial half of the extensor hallucis longus tendon is cut and a stay stitch of No. 2 ethibond is applied. It is then stripped proximally with a tendon stripper to the proximal portal. A stay stitch of No. 2 ethibond is applied to the lateral half of the tendon at the proximal portal and it is cut proximal to the stitch. With the ankle plantarflexed and the big toe kept in the similar position as the lesser toes, the tendon segments are kept in tension through the stay stitches via the proximal and distal portals. The stay stitches of distal tendon segment are sutured to the proximal segment at the same level of the cut end of the distal fragment with the aid of an eyed needle under arthroscopic visualization through the distal portal. The needle is passed through the tendon and then the skin. The suture is also passed through the skin and then retrieved to the proximal portal by a hemostat. It is then sutured to the proximal tendon segment at the proximal portal. Similarly, the proximal tendon end is sutured to the distal tendon segment at the corresponding level and the endoscopic Z-lengthening of the extensor hallucis longus tendon is then completed. PMID:17576583

  15. A 3-Dimensional Anatomic Study of the Distal Biceps Tendon

    PubMed Central

    Walton, Christine; Li, Zhi; Pennings, Amanda; Agur, Anne; Elmaraghy, Amr

    2015-01-01

    Background Complete rupture of the distal biceps tendon from its osseous attachment is most often treated with operative intervention. Knowledge of the overall tendon morphology as well as the orientation of the collagenous fibers throughout the musculotendinous junction are key to intraoperative decision making and surgical technique in both the acute and chronic setting. Unfortunately, there is little information available in the literature. Purpose To comprehensively describe the morphology of the distal biceps tendon. Study Design Descriptive laboratory study. Methods The distal biceps terminal musculature, musculotendinous junction, and tendon were digitized in 10 cadaveric specimens and data reconstructed using 3-dimensional modeling. Results The average length, width, and thickness of the external distal biceps tendon were found to be 63.0, 6.0, and 3.0 mm, respectively. A unique expansion of the tendon fibers within the distal muscle was characterized, creating a thick collagenous network along the central component between the long and short heads. Conclusion This study documents the morphologic parameters of the native distal biceps tendon. Reconstruction may be necessary, especially in chronic distal biceps tendon ruptures, if the remaining tendon morphology is significantly compromised compared with the native distal biceps tendon. Knowledge of normal anatomical distal biceps tendon parameters may also guide the selection of a substitute graft with similar morphological characteristics. Clinical Relevance A thorough description of distal biceps tendon morphology is important to guide intraoperative decision making between primary repair and reconstruction and to better select the most appropriate graft. The detailed description of the tendinous expansion into the muscle may provide insight into better graft-weaving and suture-grasping techniques to maximize proximal graft incorporation. PMID:26665092

  16. 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.

  17. 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

  18. Slicing, stacking and rolling: fabrication of nanostructured collagen constructs from tendon sections.

    PubMed

    Alberti, Kyle A; Xu, Qiaobing

    2013-06-01

    A novel method for fabricating both multilayer stacked 2D and 3D tubular constructs composed of sheets of aligned collagen fibers is described. These structures are created by decellularizing native tendon and sectioning the material into thin sheets using a cryo-microtome. This fabrication method preserves the collagens natural strength as well as the fiber structure which would aid in directing aligned cell growth. PMID:23233344

  19. Biological Augmentation of Flexor Tendon Repair: A Challenging Cellular Landscape.

    PubMed

    Loiselle, Alayna E; Kelly, Meghan; Hammert, Warren C

    2016-01-01

    Advances in surgical technique and rehabilitation have transformed zone II flexor tendon injuries from an inoperable no-man's land to a standard surgical procedure. Despite these advances, many patients develop substantial range of motion-limiting adhesions after primary flexor tendon repair. These suboptimal outcomes may benefit from biologic augmentation or intervention during the flexor tendon healing process. However, there is no consensus biological approach to promote satisfactory flexor tendon healing; we propose that insufficient understanding of the complex cellular milieu in the healing tendon has hindered the development of successful therapies. This article reviews recent advances in our understanding of the cellular components of flexor tendon healing and adhesion formation, including resident tendon cells, synovial sheath, macrophages, and bone marrow-derived cells. In addition, it examines molecular approaches that have been used in translational animal models to improve flexor tendon healing and gliding function, with a specific focus on progress made using murine models of healing. This information highlights the importance of understanding and potentially exploiting the heterogeneity of the cellular environment during flexor tendon healing, to define rational therapeutic approaches to improve healing outcomes. PMID:26652792

  20. Impact of oestrogen deficiency and aging on tendon: concise review

    PubMed Central

    Frizziero, Antonio; Vittadini, Filippo; Gasparre, Giuseppe; Masiero, Stefano

    2014-01-01

    Summary The knowledge about tendons and tenocyte biological behaviour during aging and, especially, oestrogen deficiency is limited. Women differ from men with regard to muscle and tendon, most likely due to differences in sex hormones activity and tissue response. To-date the interest in metabolic factors that may induce tendon disorders is growing. The aim of this paper is to elucidate the current findings in the correlation between oestrogen deficiency, aging and tendon pathology and to encourage future researches to ameliorate assessment and management of tendinopathies in postmenopausal women. PMID:25489550

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

    PubMed

    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

  2. Arthroscopic reconstruction of a ruptured patellar tendon: a technical note.

    PubMed

    Gokce, Alper; Ekici, Huseyin; Erdogan, Fahri

    2008-06-01

    A traumatic patellar tendon rupture of a 35-year-old, otherwise healthy male was reconstructed with semi-tendinosus and gracillis tendons. Tendon grafts were harvested with an open-ended tendon stripper without dissecting them free from their tibial insertion. A transpatellar tunnel was drilled appropriate to the tendon size and a passing pin was used across the length of the patella. Graft bundles were passed in a standard fashion, traversing through the midst of the distal part of the patellar tendon via a beath pin with a loaded looped suture. The endo-button device was then flipped and fixed as an anchor. The patella was positioned at the original placement under arthroscopic visualization and the free ends of the hamstring tendons were attached to a post-fixation screw through the Krackow sutures. Tendon grafts were gathered on the tuberositas tibia and fixed with two additional staples. The patient could flex his knee up to 130 deg at the 3-month follow-up. It was demonstrated that arthroscopic reconstruction of a ruptured patellar tendon may be the optimal surgical choice to minimize trauma and begin early rehabilitation. PMID:18322673

  3. Complications of Tendon Surgery in the Foot and Ankle.

    PubMed

    Barp, Eric A; Erickson, John G

    2016-01-01

    This article discusses four subsets of patients that have an increased risk of complications from tendon surgery in the foot and ankle: smokers, diabetics, and patients with peroneal or Achilles tendon pathology. Very little has been published on the complications of other tendon surgeries in the foot and ankle other than Achilles tendon repair. Data can be extrapolated from the general orthopedic literature and animal studies to help guide therapy and treatment options. The foot and ankle surgeon must take into account the entirety of the history and physical examination to develop a treatment plan that optimizes each patient's chance for a complication-free recovery. PMID:26590733

  4. 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. PMID:20058263

  5. Ossification of the bilateral Achilles tendon: a rare entity

    PubMed Central

    Arora, Abhishek J

    2015-01-01

    Ossification of the Achilles tendon is a rare clinical entity comprising of one or more segments of variable sized ossified masses in the fibrocartilaginous substance of the tendon. The etiology of ossification of the Achilles tendon is multifactorial with recurrent trauma and surgery comprising major predisposing factors, with others being metabolic, systemic, and infectious diseases. The possibility of a genetic predisposition towards this entity has also been raised, but has not yet been proven. We present a rare case of ossification of the bilateral Achilles tendons without any history of trauma or surgery in a 48-year-old female patient. PMID:26413314

  6. Reconstruction of neglected patellar tendon ruptures using the quadriceps graft.

    PubMed

    Gomes, João Luiz Ellera; de Oliveira Alves, Jairo André; Zimmermann, José Mauro

    2014-08-01

    Several techniques using different grafts have been described for reconstruction of the patellar tendon after a neglected rupture. Retraction of the quadriceps tendon may compromise repair integrity due to progressive stretching of the graft. The authors present a surgical technique using the central one-third of the quadriceps tendon. This is supported by the fact that the resistance to traction of this segment of the quadriceps tendon equals that of a double-looped semitendinosus graft and that the harvesting of this specific graft promotes muscle inhibition, thus protecting the reconstruction during the recovery period. PMID:25102494

  7. An alternative cruciate reconstruction graft: the central quadriceps tendon.

    PubMed

    Fulkerson, J P; Langeland, R

    1995-04-01

    The central quadriceps tendon, above the patella, is thicker and wider than the patella tendon. Using precise technique, one can obtain a tendon graft for cruciate reconstruction with 50% greater mass than a patellar tendon bone-tendon-bone graft of similar width. The central quadriceps tendon graft may be harvested by a second surgeon while the first surgeon is simultaneously accomplishing notch-plasty and tunnel placement for cruciate ligament reconstruction. Consequently, this cruciate ligament reconstruction graft offers time savings as well as greater tendon volume. The central quadriceps tendon graft is difficult to harvest, with significant risk of entering the suprapatellar pouch and losing knee distension during ACL reconstruction. By careful adherence to the technique described in this article, the surgeon can obtain this reconstruction graft safely. It is important to recognize the anatomic subtleties of the proximal patella, which include a curved proximal surface, dense cortical bone, and closely adherent suprapatellar pouch. Proper technique is of utmost importance in obtaining this tendon graft safely and efficiently. PMID:7794444

  8. 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

  9. Prevention of Tendon Adhesions by ERK2 Small Interfering RNAs

    PubMed Central

    Ruan, Hongjiang; Liu, Shen; Li, Fengfeng; Li, Xujun; Fan, Cunyi

    2013-01-01

    Tendon adhesions are one of the most concerning complications after surgical repair of flexor tendon injury. Extracellular signal-regulated kinase (ERK) 2 plays crucial roles in fibroblast proliferation and collagen expression which contributes to the formation of tendon adhesions after flexor tendon surgery. Using a chicken model, we have examined the effects of a small interfering RNA (siRNA) targeting ERK2 delivered by a lentiviral system on tendon adhesion formation with an adhesion scoring system, histological assessment, and biomechanical evaluation. It was found that ERK2 siRNA effectively suppressed the increase of fibroblasts and the formation of tendon adhesions (p < 0.05 compared with the control group). Moreover, no statistically significant reduction in breaking force was detected between the ERK2 siRNA group and the control group. These results show that the lentiviral-mediated siRNA system is effective in preventing tendon adhesion formation but not to tendon healing, and may be used for tendon repair after confirmation and improvement by future detailed studies. PMID:23429276

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

    PubMed Central

    2013-01-01

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

  11. Outcome following addition of peroneus brevis tendon transfer to treatment of acquired posterior tibial tendon insufficiency.

    PubMed

    Song, S J; Deland, J T

    2001-04-01

    The flexor digitorum longus, the tendon most often used for transfer in posterior tibial tendon insufficiency, is one-half to one-third the size of the posterior tibial tendon. Occasionally it may be particularly small or may have been previously used for transfer. In these cases, the senior author has felt that the addition of a transfer of the Peroneus Brevis (PBr) tendon may be helpful in maintaining sufficient tendon and muscle mass to rebalance the foot. Thirteen patients who underwent this procedure were retrospectively identified and matched by age and length of follow-up to patients who underwent a more standard tendon transfer operation minus the addition of the PBr transfer. Pain and functional status were then assessed by the American Orthopaedic Foot and Ankle Society's ankle/hindfoot rating scale. Each patient was tested by an independent physical therapist to evaluate inversion and eversion strength. The mean duration of follow-up was 20.6 months (12 to 34 months). The average AOFAS score of the PBr group was 75.8 compared to 71.5 for the standard control group. There was no significant difference between the groups when inversion or eversion strengths were compared. Inversion strength and eversion strength was rated good or excellent (4 or 5) in 12 out of 13 of the PBr transfer group patients. No major complications were encountered in either group. Although it does not increase inversion strength, a PBr transfer can be used to augment a small FDL without causing significant eversion weakness. This can be useful when the FDL is particularly small or in revision surgery. PMID:11354442

  12. Tendon Progenitor Cells in Injured Tendons Have Strong Chondrogenic Potential: The CD105-Negative Subpopulation Induces Chondrogenic Degeneration

    PubMed Central

    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

    2014-01-01

    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 BMPs or TGF?s. 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 co-receptor of the TGF? 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. PMID:25220576

  13. 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. PMID:21030672

  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(?-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 increased with time in culture. Histology demonstrated cell infiltration through the full thickness of all scaffolds and immunofluorescence demonstrated greater expression of type I, but not type III collagen through the full thickness of the scaffold in TDM-scaffolds compared to other treatment groups. Together, these data suggest that nonaligned multilayered electrospun scaffolds permit tenogenic differentiation by hASCs and that TDM may promote some aspects of this differentiation. PMID:23808760

  15. The Effect of Phospholipids (Surfactant) on Adhesion and Biomechanical Properties of Tendon: A Rat Achilles Tendon Repair Model

    PubMed Central

    Dabak, T. Kursat; Sertkaya, Omer; Acar, Nuray; Donmez, B. Ozgur; Ustunel, Ismail

    2015-01-01

    Adhesion of the tendon is a major challenge for the orthopedic surgeon during tendon repair. Manipulation of biological environment is one of the concepts to prevent adhesion. Lots of biochemicals have been studied for this purpose. We aimed to determine the effect of phospholipids on adhesion and biomechanical properties of tendon in an animal tendon repair model. Seventy-two Wistar rats were divided into 4 groups. Achilles tendons of rats were cut and repaired. Phospholipids were applied at two different dosages. Tendon adhesion was determined histopathologically and biomechanical test was performed. At macroscopic evaluation of adhesion, there are statistically significant differences between multiple-dose phospholipid injection group and Control group and also hyaluronic acid group and Control group (p < 0.008). At microscopic evaluation of adhesion, there was no statistically significant difference (p > 0.008). Ultimate strength was highest at hyaluronic acid injection group and lowest at multiple-dose phospholipid injection group. Single-dose phospholipids (surfactant) application may have a beneficial effect on the tendon adhesion. Although multiple applications of phospholipids seem the most effective regime to reduce the tendon adhesion among groups, it deteriorated the biomechanical properties of tendon. PMID:26101776

  16. 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

  17. Achilles tendon injuries in elite athletes: lessons in pathophysiology from their equine counterparts.

    PubMed

    Patterson-Kane, Janet C; Rich, Tina

    2014-01-01

    Superficial digital flexor tendon (SDFT) injury in equine athletes is one of the most well-accepted, scientifically supported companion animal models of human disease (i.e., exercise-induced Achilles tendon [AT] injury). The SDFT and AT are functionally and clinically equivalent (and important) energy-storing structures for which no equally appropriate rodent, rabbit, or other analogues exist. Access to equine tissues has facilitated significant advances in knowledge of tendon maturation and aging, determination of specific exercise effects (including early life), and definition of some of the earliest stages of subclinical pathology. Access to human surgical biopsies has provided complementary information on more advanced phases of disease. Importantly, equine SDFT injuries are only a model for acute ruptures in athletes, not the entire spectrum of human tendonopathy (including chronic tendon pain). In both, pathology begins with a potentially prolonged phase of accumulation of (subclinical) microdamage. Recent work has revealed remarkably similar genetic risk factors, including further evidence that tenocyte dysfunction plays an active role. Mice are convenient but not necessarily accurate models for multiple diseases, particularly at the cellular level. Mechanistic studies, including tendon cell responses to combinations of exercise-associated stresses, require a more thorough investigation of cross-species conservation of key stress pathway auditors. Molecular evidence has provided some context for the poor performance of mouse models; equines may provide better systems at this level. The use of horses may be additionally justifiable based on comparable species longevity, lifestyle factors, and selection pressure by similar infectious agents (e.g., herpesviruses) on general cell stress pathway evolution. PMID:24936032

  18. Muscle power attenuation by tendon during energy dissipation

    PubMed Central

    Konow, Nicolai; Azizi, Emanuel; Roberts, Thomas J.

    2012-01-01

    An important function of skeletal muscle is deceleration via active muscle fascicle lengthening, which dissipates movement energy. The mechanical interplay between muscle contraction and tendon elasticity is critical when muscles produce energy. However, the role of tendon elasticity during muscular energy dissipation remains unknown. We tested the hypothesis that tendon elasticity functions as a mechanical buffer, preventing high (and probably damaging) velocities and powers during active muscle fascicle lengthening. We directly measured lateral gastrocnemius muscle force and length in wild turkeys during controlled landings requiring rapid energy dissipation. Muscle-tendon unit (MTU) strain was measured via video kinematics, independent of muscle fascicle strain (measured via sonomicrometry). We found that rapid MTU lengthening immediately following impact involved little or no muscle fascicle lengthening. Therefore, joint flexion had to be accommodated by tendon stretch. After the early contact period, muscle fascicles lengthened and absorbed energy. This late lengthening occurred after most of the joint flexion, and was thus mainly driven by tendon recoil. Temporary tendon energy storage led to a significant reduction in muscle fascicle lengthening velocity and the rate of energy absorption. We conclude that tendons function as power attenuators that probably protect muscles against damage from rapid and forceful lengthening during energy dissipation. PMID:21957134

  19. 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

  20. Harnessing endogenous stem/progenitor cells for tendon regeneration

    PubMed Central

    Lee, Chang H.; Lee, Francis Y.; Tarafder, Solaiman; Kao, Kristy; Jun, Yena; Yang, Guodong; Mao, Jeremy J.

    2015-01-01

    Current stem cell–based strategies for tissue regeneration involve ex vivo manipulation of these cells to confer features of the desired progenitor population. Recently, the concept that endogenous stem/progenitor cells could be used for regenerating tissues has emerged as a promising approach that potentially overcomes the obstacles related to cell transplantation. Here we applied this strategy for the regeneration of injured tendons in a rat model. First, we identified a rare fraction of tendon cells that was positive for the known tendon stem cell marker CD146 and exhibited clonogenic capacity, as well as multilineage differentiation ability. These tendon-resident CD146+ stem/progenitor cells were selectively enriched by connective tissue growth factor delivery (CTGF delivery) in the early phase of tendon healing, followed by tenogenic differentiation in the later phase. The time-controlled proliferation and differentiation of CD146+ stem/progenitor cells by CTGF delivery successfully led to tendon regeneration with densely aligned collagen fibers, normal level of cellularity, and functional restoration. Using siRNA knockdown to evaluate factors involved in tendon generation, we demonstrated that the FAK/ERK1/2 signaling pathway regulates CTGF-induced proliferation and differentiation of CD146+ stem/progenitor cells. Together, our findings support the use of endogenous stem/progenitor cells as a strategy for tendon regeneration without cell transplantation and suggest this approach warrants exploration in other tissues. PMID:26053662

  1. Estimation of musculotendon kinematics under controlled tendon indentation.

    PubMed

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

    2015-10-15

    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 20mm 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

  2. Arthroscopic treatment of popliteus tendon dysfunction following total knee arthroplasty.

    PubMed

    Allardyce, T J; Scuderi, G R; Insall, J N

    1997-04-01

    Following total knee arthoplasty, the popliteus tendon may cause a "snap" when it rolls over a retained lateral femoral condylar osteophyte or when it subluxates over the posterior condyle of the femoral component. When this condition is painful and fails to respond to conservative treatment, arthroscopic release of the popliteus tendon has been beneficial. PMID:9113555

  3. Suitability of Thiel embalmed tendons for biomechanical investigation.

    PubMed

    Fessel, Gion; Frey, Kevin; Schweizer, Andreas; Calcagni, Maurizio; Ullrich, Oliver; Snedeker, Jess G

    2011-05-01

    The standard post-mortem storage method for biomechanical testing is freezing. Freezing minimally alters the biomechanical characteristics of tendons but only suspends the process of decay. Chemical fixation arrests decay and overcomes risk of infection, but alters the biomechanical properties of tendons. On the other hand, Thiel preservation has been reported to maintain soft tissue consistency similar to that of living tissue. The current study investigates the effects of Thiel embalming on human digitorum profundus tendons (FDP) from fresh-frozen and Thiel embalmed cadavers. Cross-sectional area was measured at pre-load, samples were preconditioned and then ramped at a constant strain-rate to failure. Thiel preserved tendons had statistically lower failure stress with median of 38MPa compared to fresh frozen samples with median of 60MPa (p-value=0.048) and trended to a decreased tangential modulus. To overcome limited donor number and masking factors of age, gender, and time embalmed, we also performed experiments in rat tail tendon fascicle. Similar quasi-static ramp to failure tests were performed with control and Thiel treated sample pairs. Similar differences were observed to those found as in human FDP, however these trends were statistically significant. In both tendons, Thiel preserved samples demonstrated altered failure characteristics, indicating a different collagen fiber/collagen network failure mechanism most likely due to partial denaturing by boric acid in Thiel solution. In conclusion, Thiel embalmed tendons did not faithfully represent the biomechanical characteristics of fresh frozen tendons. PMID:21511447

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

    PubMed Central

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

    2015-01-01

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

  5. Harnessing endogenous stem/progenitor cells for tendon regeneration.

    PubMed

    Lee, Chang H; Lee, Francis Y; Tarafder, Solaiman; Kao, Kristy; Jun, Yena; Yang, Guodong; Mao, Jeremy J

    2015-07-01

    Current stem cell-based strategies for tissue regeneration involve ex vivo manipulation of these cells to confer features of the desired progenitor population. Recently, the concept that endogenous stem/progenitor cells could be used for regenerating tissues has emerged as a promising approach that potentially overcomes the obstacles related to cell transplantation. Here we applied this strategy for the regeneration of injured tendons in a rat model. First, we identified a rare fraction of tendon cells that was positive for the known tendon stem cell marker CD146 and exhibited clonogenic capacity, as well as multilineage differentiation ability. These tendon-resident CD146+ stem/progenitor cells were selectively enriched by connective tissue growth factor delivery (CTGF delivery) in the early phase of tendon healing, followed by tenogenic differentiation in the later phase. The time-controlled proliferation and differentiation of CD146+ stem/progenitor cells by CTGF delivery successfully led to tendon regeneration with densely aligned collagen fibers, normal level of cellularity, and functional restoration. Using siRNA knockdown to evaluate factors involved in tendon generation, we demonstrated that the FAK/ERK1/2 signaling pathway regulates CTGF-induced proliferation and differentiation of CD146+ stem/progenitor cells. Together, our findings support the use of endogenous stem/progenitor cells as a strategy for tendon regeneration without cell transplantation and suggest this approach warrants exploration in other tissues. PMID:26053662

  6. Ultrasound Diagnosis of Bilateral Quadriceps Tendon Rupture After Statin Use

    PubMed Central

    Nesselroade, Ryan D.; Nickels, Leslie Connor

    2010-01-01

    Simultaneous bilateral quadriceps tendon rupture is a rare injury. We report the case of bilateral quadriceps tendon rupture sustained with minimal force while refereeing a football game. The injury was suspected to be associated with statin use as the patient had no other identifiable risk factors. The diagnosis was confirmed using bedside ultrasound. PMID:21079697

  7. Granuloma formation secondary to Achilles tendon repair with nonabsorbable suture

    PubMed Central

    Kara, Adnan; Celik, Haluk; Seker, Ali; Uysal, Mehmet Ali; Uzun, Metin; Malkoc, Melih

    2014-01-01

    INTRODUCTION Several complications can be observed after Achilles tendon repairs. In this study we aimed to report granuloma formation secondary to Achilles tendon repair with Ethibond (Ethicon INC, Somerville, New Jersey) suture. PRESENTATION OF CASE A 31 year-old man operated for Achilles tendon rupture. The Ethibond suture was used for primary repair. The patient attended to polyclinic with the complaints of swelling and discharge around the operation site four months after operation. A mass around distal portion of the Achilles tendon was detected. The granulomatous tissue was excised. Inside the mass Ethibond suture was detected. On histopathologic examination, typical findings of the foreign body reaction were observed. No microorganism was cultivated in the tissue culture. The patient has no complaint on the twelfth month control after surgery. DISCUSSION The results of primary repair of Achilles tendon are good but several complications were reported. In tendon repairs generally nonabsorbable sutures are used. The Ethibond is nonabsorbable, braided suture. In the literature, granuloma formations secondary to the suture materials such as polygylactine and braided polyethylen–polyester after Achilles tendon repair were reported but granuloma secondary to the Ethibond is very rare. CONCLUSION Although Ethibond suture is a strong and safe material for Achilles tendon repairs it may cause soft tissue problems such as granuloma. PMID:25212905

  8. [Magnetic resonance tomography in the assessment of anterior cruciate ligament reconstruction by tendon grafts].

    PubMed

    Allgayer, B; Gradinger, R; Lehner, K; Flock, K; Gewalt, Y

    1991-10-01

    150 patients were examined via magnetic resonance (MR) after anterior cruciate (ACL) ligament reconstruction (76 patellar tendon grafts, 53 semitendinous tendon grafts and 21 sutures). The results of MR were compared with clinical tests (Lachman, pivot-shift and anterior drawer test), in 2 cases with the operative findings, and in one case with arthroscopy findings. In 91% of patients with a clinically stable knee we found a continuous low-intensity ligamental structure. 10 patients were examined twice or more between 8 days and 6 months after surgery. Ligamental structures of low signal intensity did not significantly change their MR characteristics. MR is a valuable noninvasive method for evaluating ligament reconstructions. PMID:1932723

  9. Achilles Tendon Open Repair Augmented with Volar Turndown Tendon Flap and Deep Posterior Crural Fasciotomy

    PubMed Central

    Özer, Hamza; Selek, Hakan; Harput, Gülcan; Öznur, Ali; Baltac?, Gül

    2014-01-01

    Objectives: The aim of the study was to investigate the outcomes after open repair of Achilles tendon rupture with augmented volar turndown gastrocnemius flap and deep posterior crural fasciotomy. Methods: Twenty-three (22male/1female) patients with acute Achilles tendon injury were operated. Open end to end repair and augmentation with a volar turndown gastrocnemius flap and fasciotomy of the deep posterior compartment was performed in each patient. Home physiotherapy program was instructed for each patient. Muscle strength, balance and jump performance were assessed. Results: All patients returned to their preinjury activity level and repairs healed without any major complication. One patient had serous drainage who did not require surgical intervention (4,3%). There was no significant difference between involved and uninvolved leg in terms of concentric and eccentric muscle strength (p=0.82 and p=0.53, respectively). In Y balance test, there was no significant difference between involved and uninvolved legs in anterior (p=0.06), posteromedial (p=0.97) and posterolateral (p=1.00). In addition, there were no significant differences between leg in vertical jump (p=0.16) and one leg hop (p=0.15) tests. AOFAS Hindfoot score was 98.6±2.3 (93-100). Conclusion: Open end to end repair of the Achilles tendon rupture with augmentation and fasciotomy of the deep posterior compartment healed without any major complication. Fasciotomy of the deep posterior compartment decreased the tension at the skin repair site while decompressing the supeficial compartment anteriorly. Additionally, the augmented bulky repair construct of the Achilles tendon cambered volarly through the deep posterior compartment and decreased irritation sense during and after tendon healing.

  10. 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.

  11. 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.

  12. A New Clinical Test in Diagnosing Quadriceps Tendon Rupture

    PubMed Central

    Jolles, BM; Garofalo, R; Gillain, L; Schizas, C

    2007-01-01

    INTRODUCTION Extensor mechanism ruptures might be easily overlooked and misdiagnosed, and delayed diagnosis of quadriceps tendon rupture is frequent. However, the literature recommends early surgical repair within 72 h. PATIENTS AND METHODS This paper describes a new simple clinical diagnostic test that directly evaluates the integrity of the distal 5 cm of the quadriceps tendon itself. It consists of inserting a needle in the tendon, proximal to the suspected rupture and mobilising the knee joint. RESULTS The suspected ruptured quadriceps tendons with a positive ‘needle’ diagnostic test were confirmed intra-operatively. CONCLUSIONS This minimally invasive and easily available technique should be considered in the diagnostic work-up and treatment planning of patients with suspected tears of the quadriceps tendon. PMID:17394710

  13. Continuum model of tendon pathology – where are we now?

    PubMed Central

    McCreesh, Karen; Lewis, Jeremy

    2013-01-01

    Chronic tendon pathology is a common and often disabling condition, the causes of which remain poorly understood. The continuum model of tendon pathology was proposed to provide a model for the staging of tendon pathology and to assist clinicians in managing this often complex condition (Br. J. Sports Med., 43, 2009, 409). The model presents clinical, histological and imaging evidence for the progression of tendon pathology as a three-stage continuum: reactive tendinopathy, tendon disrepair and degenerative tendinopathy. It also provides clinical information to assist in identifying the stage of pathology, in addition to proposed treatment approaches for each stage. The usefulness of such a model is determined by its ability to incorporate and inform new and emerging research. This review examines the degree to which recent research supports or refutes the continuum model and proposes future directions for clinical and research application of the model. PMID:23837792

  14. 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.

  15. 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.

  16. [Distal biceps tendon tear. A case report].

    PubMed

    Alanis Blancas, Luis Manuel; Zamora Muñoz, Paola Maritza; Cruz Miranda, Angel

    2009-01-01

    Distal tears of the biceps tendon are rare lesions and account for 3-5% of all biceps lesions. Surgical treatment produces better outcomes than conservative treatment from the perspective of forearm flexion and supination. Different implants and approaches are currently available to improve the course of patients and reduce the postoperative complications. The case of a patient who underwent surgical treatment with anatomical reattachment with anchors is presented herein as well as his two-year follow-up. This is considered as an excellent outcome given that the patient remained asymptomatic and returned to his previous athletic activity without complications. PMID:19960662

  17. Pectoralis major tendon rupture. Surgical procedures review.

    PubMed Central

    Merolla, Giovanni; Paladini, Paolo; Campi, Fabrizio; Porcellini, Giuseppe

    2012-01-01

    Summary Pectoralis major (PM) muscle is the powerful dynamic stabiliser of the shoulder that acts as a flexor, adductor and internal rotator. The rupture of the PM tendon is a relatively rare injury that was firstly described in a French boy by Patissier in 1822 and later, in 1861, by Letenneur who reported another similiar case. To date, over 200 cases have been published. In this article we describe the clinical anatomy and the mechanism of injuries of PM and we review the surgical procedures for acute and chronic ruptures. PMID:23738281

  18. The anisotropic compressive mechanical properties of the rabbit patellar tendon.

    PubMed

    Williams, Lakiesha N; Elder, Steven H; Bouvard, J L; Horstemeyer, M F

    2008-01-01

    In this study, we examine the transverse and longitudinal compressive mechanical behavior of the rabbit patellar tendon. The anisotropic compressive properties are of interest, because compression occurs where the tendon attaches to bone and where the tendon wraps around bone leading to the development of fibro-cartilaginous matrices. We quantified the time dependent viscoelastic and anisotropic behavior of the tendon under compression. For both orientations, sections of patellar tendon were drawn from mature male white New Zealand rabbits in preparation for testing. The tendons were sequentially compressed to 40% strain at strain rates of 0.1, 1 and 10% strain(s) using a computer-controlled stepper motor driven device under physiological conditions. Following monotonic loading, the tendons were subjected to stress relaxation. The tendon equilibrium compressive modulus was quantified to be 19.49+/-11.46 kPa for the transverse direction and 1.11+/-0.57 kPa for the longitudinal direction. The compressive modulus at applied strain rates of 0.1, 1 and 10% strain(s) in the transverse orientation were 13.48+/-2.31, 18.24+/-4.58 and 20.90+/-8.60 kPa, respectively. The compressive modulus at applied strain rates of 0.1, 1 and 10% strain/s in the longitudinal orientation were 0.19+/-0.11, 1.27+/-1.38 and 3.26+/-3.49 kPa, respectively. The modulus values were almost significantly different for the examination of the effect of orientation on the equilibrium modulus (p=0.054). Monotonic loading of the tendon showed visual differences of the strain rate dependency; however, no significant difference was shown in the statistical analysis of the effect of strain rate on compressive modulus. The statistical analysis of the effect of orientation on compressive modulus showed a significant difference. The difference shown in the orientation analysis validated the anisotropic nature of the tendon. PMID:19065006

  19. Human patellar tendon stiffness is restored following graft harvest for anterior cruciate ligament surgery.

    PubMed

    Reeves, Neil D; Maganaris, Constantinos N; Maffulli, Nicola; Rittweger, Joern

    2009-05-11

    Minimising post-operative donor site morbidity is an important consideration when selecting a graft for surgical reconstruction of the torn anterior cruciate ligament (ACL). One of the most common procedures, the bone-patellar tendon-bone (BPTB) graft involves removal of the central third from the tendon. However, it is unknown whether the mechanical properties of the donor site (patellar tendon) recover. The present study investigated the mechanical properties of the human patellar tendon in 12 males (mean+/-S.D. age: 37+/-14 years) who had undergone surgical reconstruction of the ACL using a BPTB graft between 1 and 10 years before the study (operated knee; OP). The uninjured contralateral knee served as a control (CTRL). Patellar tendon mechanical properties were assessed in vivo combining dynamometry with ultrasound imaging. Patellar tendon stiffness was calculated from the gradient of the tendon's force-elongation curve. Tendon stiffness was normalised to the tendon's dimensions to obtain the tendon's Young's modulus. Cross-sectional area (CSA) of OP patellar tendons was larger by 21% than CTRL tendons (P<0.01). Patellar tendon stiffness was not significantly different between OP and CTRL tendons, but the Young's modulus was lower by 24% in OP tendons (P<0.01). A compensatory enlargement of the patellar tendon CSA, presumably due to scar tissue formation, enabled a recovery of tendon stiffness in the OP tendons. The newly formed tendon tissue had inferior properties as indicated by the reduced tendon Young's modulus, but it increased to a level that enabled recovery of tendon stiffness. PMID:19268289

  20. Influence of neglecting the curved path of the Achilles tendon on Achilles tendon length change at various ranges of motion

    PubMed Central

    Fukutani, Atsuki; Hashizume, Satoru; Kusumoto, Kazuki; Kurihara, Toshiyuki

    2014-01-01

    Abstract Achilles tendon length has been measured using a straight?line model. However, this model is associated with a greater measurement error compared with a curved?line model. Therefore, we examined the influence of neglecting the curved path of the Achilles tendon on its length change at various ranges of motion. Ten male subjects participated in this study. First, the location of the Achilles tendon was confirmed by using ultrasonography, and markers were attached on the skin over the Achilles tendon path. Then, the three?dimensional coordinates of each marker at dorsiflexion (DF) 15°, plantarflexion (PF) 0°, PF15°, and PF30° were obtained. Achilles tendon length in the curved?line model was calculated as the sum of the distances among each marker. On the other hand, Achilles tendon length in the straight?line model was calculated as the straight distance between the two most proximal and distal markers projected onto the sagittal plane. The difference of the Achilles tendon length change between curved?line and straight?line models was calculated by subtracting the Achilles tendon length change obtained in curved?line model from that obtained in straight?line model with three different ranges of motion (i.e., PF0°, PF15°, and PF30° from DF15°, respectively). As a result, the difference in Achilles tendon length change between the two models increased significantly as the range of motion increased. In conclusion, neglecting the curved path of the Achilles tendon induces substantial overestimation of its length change when the extent of ankle joint angle change is large. PMID:25303951

  1. COMPLICATIONS OF JOINT, TENDON, AND MUSCLE INJECTIONS.

    PubMed

    Cheng, Jianguo; Abdi, Salahadin

    2007-07-01

    Prevention of complications is one of the most important aspects of patient care in pain management. The objective of this study is to review documented complications in medical literature that are associated with interventional pain management, specifically those associated with joint, tendon, and muscle injections. We conducted Medline research from 1966 to November 2006 using keywords complication, injection, radiofrequency, closed claim, facet, zygophyseal joint, sacroiliac joint, shoulder, hip, knee, carpel tunnel, bursa, and trigger point. We found over 35 relevant papers in forms of original articles, case reports, and reviews. The most common complications appear to be infections that have been associated with virtually all of these injections. These infections include spondylodiscitis, septic arthritis, epidural abscess, necrotizing fasciitis, osteomyelitis, gas gangrene, and albicans arthritis. Other complications include spinal cord injury and peripheral nerve injuries, pneumothorax, air embolism, pain or swelling at the site of injection, chemical meningism, granulomatous inflammation of the synovium, aseptic acute arthritis, embolia cutis medicamentosa, skeletal muscle toxicity, and tendon and fascial ruptures. We suggest that many of the infectious complications may be preventable by strict adherence to aseptic techniques and that some of the other complications may be minimized by refining the procedural techniques with a clear understanding of the relevant anatomies. PMID:18591992

  2. Acute Achilles tendon rupture in badminton players.

    PubMed

    Fahlström, M; Björnstig, U; Lorentzon, R

    1998-01-01

    All patients with badminton-related acute Achilles tendon ruptures registered during 1990 to 1994 at the University Hospital of Umeå were retrospectively followed up using a questionnaire. Thirty-one patients (mean age, 36.0 years), 27 men and 4 women, were included. Thirty patients (97%) described themselves as recreational players or beginners. The majority of the injuries (29 of 31, 94%) happened at the middle or end of the planned game. Previous local symptoms had been noticed by five patients (16%). Long-term results showed that patients treated with surgery had a significantly shorter sick leave absence than patients treated without surgery (50 versus 75 days). There was no obvious selection favoring any treatment modality. None of the surgically treated patients had reruptures, but two reruptures occurred in the nonsurgically treated group. There seemed to be fewer remaining symptoms and a higher sports activity level after the injury in the surgically treated group. Our results indicate that local muscle fatigue may interfere with strength and coordination. Preventive measures such as specific treatment of minor injuries and adequate training of strength, endurance, and coordination are important. Our findings also indicate that surgical treatment and careful postoperative rehabilitation is of great importance among badminton players of any age or sports level with Achilles tendon rupture. PMID:9617415

  3. Architecture and functional ecology of the human gastrocnemius muscle-tendon unit.

    PubMed

    Butler, Erin E; Dominy, Nathaniel J

    2016-04-01

    The gastrocnemius muscle-tendon unit (MTU) is central to human locomotion. Structural variation in the human gastrocnemius MTU is predicted to affect the efficiency of locomotion, a concept most often explored in the context of performance activities. For example, stiffness of the Achilles tendon varies among individuals with different histories of competitive running. Such a finding highlights the functional variation of individuals and raises the possibility of similar variation between populations, perhaps in response to specific ecological or environmental demands. Researchers often assume minimal variation in human populations, or that industrialized populations represent the human species as well as any other. Yet rainforest hunter-gatherers, which often express the human pygmy phenotype, contradict such assumptions. Indeed, the human pygmy phenotype is a potential model system for exploring the range of ecomorphological variation in the architecture of human hindlimb muscles, a concept we review here. PMID:26712532

  4. Histopathology in rabbit Achilles tendon after operative tenolysis (longitudinal fiber incisions).

    PubMed

    Friedrich, T; Schmidt, W; Jungmichel, D; Horn, L C; Josten, C

    2001-02-01

    The surgical treatment (tenolysis) of chronic Achilles tendinopathy is often successful. However, little is known about the postoperative intratendinous changes after this procedure. The study group consisted of 21 rabbits. Operative tenolysis was done in each case on one Achilles tendon (AT). The ATs of both legs were studied histologically and immunohistochemically using antibodies against collagen types I and III 2, 4 and 6 weeks postoperatively. Nine rabbits without operation served as controls. A significant uniform hypervascularization was noted in the entire operated tendon postoperatively, and this concurred with the contralateral nonoperated AT, but neither side showed changes in collagen fiber structure as judged by immunohistochemistry. We conclude that the tenolysis procedure triggers neoangiogenesis at the AT followed by increased blood flow and improved nutrition in the same. These changes could, at least partly, explain the often seen clinical success in surgically treated tendinopathy. PMID:11169228

  5. In-depth imaging and quantification of degenerative changes associated with Achilles ruptured tendons by polarization-sensitive optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Bagnaninchi, P. O.; Yang, Y.; Bonesi, M.; Maffulli, G.; Phelan, C.; Meglinski, I.; El Haj, A.; Maffulli, N.

    2010-07-01

    The objective of this study was to develop a method based on polarization-sensitive optical coherent tomography (PSOCT) for the imaging and quantification of degenerative changes associated with Achilles tendon rupture. Ex vivo PSOCT examinations were performed in 24 patients. The study involved samples from 14 ruptured Achilles tendons, 4 tendinopathic Achilles tendons and 6 patellar tendons (collected during total knee replacement) as non-ruptured controls. The samples were imaged in both intensity and phase retardation modes within 24 h after surgery, and birefringence was quantified. The samples were fixed and processed for histology immediately after imaging. Slides were assessed twice in a blind manner to provide a semi-quantitative histological score of degeneration. In-depth micro structural imaging was demonstrated. Collagen disorganization and high cellularity were observable by PSOCT as the main markers associated with pathological features. Quantitative assessment of birefringence and penetration depth found significant differences between non-ruptured and ruptured tendons. Microstructure abnormalities were observed in the microstructure of two out of four tendinopathic samples. PSOCT has the potential to explore in situ and in-depth pathological change associated with Achilles tendon rupture, and could help to delineate abnormalities in tendinopathic samples in vivo.

  6. Current Concepts in Examination and Treatment of Elbow Tendon Injury

    PubMed Central

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

    2013-01-01

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

  7. Quantification of regional blood flow to canine flexor tendons

    SciTech Connect

    Weidman, K.A.; Simonet, W.T.; Wood, M.B.; Cooney, W.P.; Ilstrup, D.M.

    1984-01-01

    Although the blood supply and the microcirculation of flexor tendons have been studied and defined extensively using qualitative methods, the quantitative assessment of blood flow has been lacking because of the limitations of the available experimental techniques. The authors studied the regional blood supply to the flexor tendons of dogs by the technique of radionuclide-labeled microspheres. Seven adult mongrel dogs were used. Microsphere injection and tissue-counting techniques previously used for other tissues were applied. Samples of proximal, isthmus, and distal portions of the profundus and superficialis flexor tendons were harvested from each digital unit of available limbs from each dog. Mean (+/- SE) flows (ml/100 g dry tissue/min) were proximal profundus 1.78 +/- 0.60 and superficialis 7.10 +/- 1.50. The differences were significant. The study suggests that regional variation in blood flow to canine digital flexor tendons exists, so that a single value for blood flow to these tendons is not relevant. Furthermore, the study supports the concept of dual (vascular and synovial) nutrition to the digital flexor tendons in dogs. These observations may have implications regarding tendon repair techniques.

  8. Sutured tendon repair; a multi-scale finite element model.

    PubMed

    Rawson, Shelley D; Margetts, Lee; Wong, Jason K F; Cartmell, Sarah H

    2015-01-01

    Following rupture, tendons are sutured to reapproximate the severed ends and permit healing. Several repair techniques are employed clinically, with recent focus towards high-strength sutures, permitting early active mobilisation thus improving resultant joint mobility. However, the arrangement of suture repairs locally alters the loading environment experienced by the tendon. The extent of the augmented stress distribution and its effect on the tissue is unknown. Stress distribution cannot be established using traditional tensile testing, in vivo, or ex vivo study of suture repairs. We have developed a 3D finite element model of a Kessler suture repair employing multiscale modelling to represent tendon microstructure and incorporate its highly orthotropic behaviour into the tissue description. This was informed by ex vivo tensile testing of porcine flexor digitorum profundus tendon. The transverse modulus of the tendon was 0.2551 ± 0.0818 MPa and 0.1035 ± 0.0454 MPa in proximal and distal tendon samples, respectively, and the interfibrillar tissue modulus ranged from 0.1021 to 0.0416 MPa. We observed an elliptically shaped region of high stress around the suture anchor, consistent with a known region of acellularity which develop 72 h post-operatively and remain for at least a year. We also observed a stress shielded region close to the severed tendon ends, which may impair collagen fibre realignment during the remodelling stage of repair due to the lack of tensile stress. PMID:24840732

  9. Development of a tendon driven system using a pneumatic balloon

    NASA Astrophysics Data System (ADS)

    Sato, Rika; Nagase, Jun-ya; Saga, Norihiko; Chonan, Seiji

    2007-01-01

    This paper is a study on a new type of a tendon system driven by a pneumatic balloon. It consists of a tendon and a silicon tube. Both ends of the silicon tube are closed and the tube expands like a balloon with the supply of air, which distends the silicon tube and pulls the tendon. Two types of actuation systems are considered. One is a high power system while the other a long stroke type. These two actuation systems have a difference in the mechanism of driving the tendon. In the high power system, the tendon is wound around the balloon. On the other hand, for the long stroke type, one end of the tendon is clamped near the balloon. The states of expansion are examined for both the high power type and the long stroke type. A cover is introduced to prevent the excessive expansion of the inflated balloon. The basic characteristics of the two tendon systems are discussed. A comparison with a human muscle is also presented.

  10. Successful management of bilateral patellar tendon rupture in a dog.

    PubMed

    Shipov, A; Shahar, R; Joseph, R; Milgram, J

    2008-01-01

    A seven-year-old, 41 kg, intact, cross breed dog, was presented with a history of bilateral hind limb lameness after falling from a height of 1 m. Clinical and radiographic findings were consistent with bilateral patellar tendon rupture. Surgical repair was performed bilaterally. The tendons were sutured primarily, and an internal splint of nylon leader was added. Good apposition of the severed tendon ends had been achieved intraoperatively; however, post operative radiographs showed supra-trochlear displacement of both patellae. The casts used to immobilize the stifle joints slipped distally and three days post operatively the tendon repair had broken down, bilaterally. Revision surgery was undertaken and the tendons were re-sutured. Nylon leader was placed through holes that had been drilled in the patellae and tibiae. The stifle joints were immobilized with type I external skeletal fixators (ESFs). Both freeform polymethylmethacrylate (PMMA) connecting bars were found to be broken at the level of the stifle joints two days later, without any disruption of the primary tendon repair. Each connecting bar was replaced with two connecting bars of PMMA reinforced with 3 mm steel wire. The dog was fully weight-bearing with a reduced range of motion in flexion immediately after removal of the ESFs at six weeks and was still sound 18 months post-operatively. Primary tendon repair in combination with adequate immobilization allowed for an excellent outcome in a complicated bilateral pathology. PMID:18545725

  11. Quantification of regional blood flow to canine flexor tendons.

    PubMed

    Weidman, K A; Simonet, W T; Wood, M B; Cooney, W P; Ilstrup, D M

    1984-01-01

    Although the blood supply and the microcirculation of flexor tendons have been studied and defined extensively using qualitative methods, the quantitative assessment of blood flow has been lacking because of the limitations of the available experimental techniques. We studied the regional blood supply to the flexor tendons of dogs by the technique of radionuclide-labeled microspheres. Seven adult mongrel dogs were used. Microsphere injection and tissue-counting techniques previously used for other tissues were applied. Samples of proximal, isthmus, and distal portions of the profundus and superficialis flexor tendons were harvested from each digital unit of available limbs from each dog. Mean (+/- SE) flows (ml/100 g dry tissue/min) were proximal profundus 1.78 +/- 0.60 and superficialis 7.10 +/- 1.50. The differences were significant (p less than 0.01). The study suggests that regional variation in blood flow to canine digital flexor tendons exists, so that a single value for blood flow to these tendons is not relevant. Furthermore, the study supports the concept of dual (vascular and synovial) nutrition to the digital flexor tendons in dogs. These observations may have implications regarding tendon repair techniques. PMID:6491815

  12. 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

  13. Ablating hedgehog signaling in tenocytes during development impairs biomechanics and matrix organization of the adult murine patellar tendon enthesis.

    PubMed

    Breidenbach, Andrew P; Aschbacher-Smith, Lindsey; Lu, Yinhui; Dyment, Nathaniel A; Liu, Chia-Feng; Liu, Han; Wylie, Chris; Rao, Marepalli; Shearn, Jason T; Rowe, David W; Kadler, Karl E; Jiang, Rulang; Butler, David L

    2015-08-01

    Restoring the native structure of the tendon enthesis, where collagen fibers of the midsubstance are integrated within a fibrocartilaginous structure, is problematic following injury. As current surgical methods fail to restore this region adequately, engineers, biologists, and clinicians are working to understand how this structure forms as a prerequisite to improving repair outcomes. We recently reported on the role of Indian hedgehog (Ihh), a novel enthesis marker, in regulating early postnatal enthesis formation. Here, we investigate how inactivating the Hh pathway in tendon cells affects adult (12-week) murine patellar tendon (PT) enthesis mechanics, fibrocartilage morphology, and collagen fiber organization. We show that ablating Hh signaling resulted in greater than 100% increased failure insertion strain (0.10?v. 0.05?mm/mm, p<0.01) as well as sub-failure biomechanical deficiencies. Although collagen fiber orientation appears overtly normal in the midsubstance, ablating Hh signaling reduces mineralized fibrocartilage by 32%, leading to less collagen embedded within mineralized tissue. Ablating Hh signaling also caused collagen fibers to coalesce at the insertion, which may explain in part the increased strains. These results indicate that Ihh signaling plays a critical role in the mineralization process of fibrocartilaginous entheses and may be a novel therapeutic to promote tendon-to-bone healing. PMID:25807894

  14. 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.

  15. Effect of training and sudden detraining on the patellar tendon and its enthesis in rats

    PubMed Central

    2011-01-01

    Background Different conditions may alter tendon characteristics. Clinical evidence suggests that tendon injuries are more frequent in athletes that change type, intensity and duration of training. Aim of the study was the assessment of training and especially detraining on the patellar tendon (PT) and its enthesis. Methods 27 male adult Sprague-Dawley rats were divided into 3 groups: 20 rats were trained on a treadmill for 10 weeks. Of these, 10 rats were euthanized immediately after training (trained group), and 10 were caged without exercise for 4 weeks before being euthanized (de-trained group). The remaining 7 rats were used as controls (untrained rats). PT insertion, structure (collagen fiber organization and proteoglycan, PG, content), PT thickness, enthesis area, and subchondral bone volume at the enthesis were measured by histomorphometry and microtomography. Results Both PG content and collagen fiber organization were significantly lower in untrained and detrained animals than in trained ones (p < 0.05 and p < 0.0001). In the detrained group, fiber organization and PG content were worse than that of the untrained groups and the untrained group showed a significantly higher score than the detrained group (p < 0.05). In the trained group, the PT was significantly thicker than in untrained group (p < 0.05). No significant differences in the enthesis area and subchondral bone volume among the three groups were seen. Conclusions Moderate exercise exerts a protective effect on the PT structure while sudden discontinuation of physical activity has a negative effect on tendons. The present results suggest that after a period of sudden de-training (such as after an injury) physical activity should be restarted with caution and with appropriate rehabilitation programs. PMID:21247475

  16. Tendon bottom connector for a tension leg platform

    SciTech Connect

    Kipp, R.M.

    1991-04-02

    This patent describes a floating tension-leg platform having anchoring tendons extending from the platform with the lower ends of the tendons being connected in tension to anchor means fixedly secured to the ocean floor in deep water, the connection being made by underwater-actuatable and remotely-connectable and releasable tendon connector means. It includes first and second connector portions a first inwardly-directed camming surface; a circumferential latching groove; a latching shoulder; a second camming surface; a latching sleeve; collet spring fingers; and outwardly-extending latches.

  17. Resection of the common digital extensor tendon in a gelding.

    PubMed

    Booth, T M; Clegg, P D; Singer, E R; Cheeseman, M T

    2000-03-25

    A four-year-old gelding was lame owing to a chronic septic common digital extensor tendon and sheath. The horse had been treated by open surgical lavage but the sepsis had recurred after three months. Physical, ultrasonographic, cytological and histological examinations confirmed chronic septic tenosynovitis and tendonitis. The entire intrathecal component of the common digital extensor tendon was resected under general anaesthesia and the synovial lining of the sheath was ablated. Postoperatively the horse regained good limb function and became sound. PMID:10803983

  18. Triceps tendon tear in a middle-aged weightlifter.

    PubMed

    Molloy, Joseph M; Aberle, Curtis J; Escobar, Eduardo

    2013-11-01

    The patient was a 47-year-old man who was evaluated by a physical therapist for a chief complaint of posterior right elbow pain. The patient routinely participated in weightlifting activities and reported a sudden onset of triceps weakness and posterior elbow pain while performing clap push-ups 3 days prior. A physician assistant ordered radiographs, which were initially interpreted as normal, and routine magnetic resonance imaging for the right elbow. Following examination by a physical therapist, due to concern for a triceps tendon tear, the previously ordered magnetic resonance imaging was expedited, which revealed a partial triceps tendon tear with partial tendon retraction medially. PMID:24175622

  19. 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

  20. Tenascin-C Expression in Equine Tendon-derived Cells During Proliferation and Migration.

    PubMed

    Nemoto, Manabu; Kizaki, Keiichiro; Yamamoto, Yoshio; Oonuma, Toshina; Hashizume, Kazuyoshi

    2013-01-01

    In vitro cell studies might be a useful tool for studying tendon pathology, but no suitable in vitro models exist for tendon disorders. The purpose of this study was to confirm whether cell scratch culture using tendon-derived fibroblasts can provide a suitable in vitro tendon disorder model. Extracellular matrix components were examined immunohistochemically in tendon tissue, and then their related gene expression levels were analyzed by conventional reverse transcription polymerase chain reaction (RT-PCR) and/or quantitative real-time RT-PCR in tissues and cells. Collagen type I (Col I), collagen type III (Col III), tenascin-C (TN-C) and cartilage oligomeric matrix protein (COMP) were detected in tendon tissue sections, and RT-PCR confirmed their expression in tendon tissue and cells. Cells that had been cultured from explanted tendon tissue maintained the characteristics of in vivo tendon cells. The combination of TN-C and COMP might be a useful marker of tendon cells because they display more tendon-specific expression than Col I and III. In particular, the significant increase of TN-C mRNA expression in the scratch wound assay, at 12 hr after scratching, concomitant with the regeneration of the cell sheet, indicates its crucial role in tendon cell proliferation and migration. Thus, TN-C appears to be a key factor in tendon wound healing. In vitro cell scratch assays using tendon cells appear to mimic the repair of tendon tissue after injury. PMID:24833997

  1. Compressive properties of cd-HA-gelatin modified intrasynovial tendon allograft in canine model in vivo

    PubMed Central

    Ikeda, Jun; Zhao, Chunfeng; Chen, Qingshan; Thoreson, Andrew R.; An, Kai-Nan; Amadio, Peter C.

    2013-01-01

    Although we sometimes use the intrasynovial tendon allograft as a donor, the gliding ability of allograft prepared by lyophilization is significantly decreased. The gliding ability of the grafted tendon after tendon reconstruction is very important because the high gliding resistance causes more adhesion and leads to poor clinical results. We recently revealed that tendon surface treatment with a carbodiimide derivatized HA (cd-HA)-gelatin mixture for intrasynovial tendon allograft significantly improved its gliding ability. The purpose of this study was to investigate whether this cd-HA-gelatin treatment affects the tendon mechanical property or not. A total of 40 flexor digitorum profundus (FDP) tendons from canines were evaluated for compressive property by using indentation test. Indentation stiffness was measured for normal tendon, rehydrated tendon after lyophilization, rehydrated tendon after lyophilization that was implanted 6 weeks in vivo, and cd-HA treated rehydrated tendon after lyophilization that was implanted 6 weeks in vivo. The results for all groups showed no significant difference in the tendon compressive properties. The findings of these results demonstrate that cd-HA treatment for intrasynovial tendon allograft is an excellent method to improve the tendon gliding ability after lyophilization without changing the compressive property of donor tendon. PMID:21549380

  2. Low-Magnitude, High-Frequency Vibration Fails to Accelerate Ligament Healing but Stimulates Collagen Synthesis in the Achilles Tendon

    PubMed Central

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

    2015-01-01

    Background: Low-magnitude, high-frequency vibration accelerates fracture and wound healing and prevents disuse atrophy in musculoskeletal tissues. Purpose: To investigate the role of low-magnitude, high-frequency vibration as a treatment to accelerate healing of an acute ligament injury and to examine gene expression in the intact Achilles tendon of the injured limb after low-magnitude, high-frequency vibration. Study Design: Controlled laboratory study. Methods: Complete surgical transection of the medial collateral ligament (MCL) was performed in 32 Sprague-Dawley rats, divided into control and low-magnitude, high-frequency vibration groups. Low-magnitude, high-frequency vibration started on postoperative day 2, and rats received vibration for 30 minutes a day for 12 days. All rats were sacrificed 2 weeks after the operation, and their intact and injured MCLs were biomechanically tested or used for histological analysis. Intact Achilles tendons from the injured limb were evaluated for differences in gene expression. Results: Mechanical testing revealed no differences in the ultimate tensile load or the structural stiffness between the control and vibration groups for either the injured or intact MCL. Vibration exposure increased gene expression of collagen 1 alpha (3-fold), interleukin 6 (7-fold), cyclooxygenase 2 (5-fold), and bone morphogenetic protein 12 (4-fold) in the intact Achilles tendon when compared with control tendons (P < .05). Conclusion: While no differences were observed in the mechanical or histological properties of the fully transected MCL after low-magnitude, high-frequency vibration treatment, significant enhancements in gene expression were observed in the intact Achilles tendon. These included collagen, several inflammatory cytokines, and growth factors critical for tendons. Clinical Relevance: As low-magnitude, high-frequency vibration had no negative effects on ligament healing, vibration therapy may be a useful tool to accelerate healing of other tissues (bone) in multitrauma injuries without inhibiting ligament healing. Additionally, the enhanced gene expression in response to low-magnitude, high-frequency vibration in the intact Achilles tendon suggests the need to further study its potential to accelerate tendon healing in partial injury or repair models. PMID:26086026

  3. 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.

  4. 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

  5. Late quadriceps tendon rupture at the donor site following cruciate ligament reconstruction using central quadriceps tendon graft.

    PubMed

    Pandey, Vivek; Madi, Sandesh; Joseph, Amy; Acharya, Kiran

    2015-01-01

    Central quadriceps tendon (CQT) graft has been successfully used as a viable autograft option in cruciate ligament reconstruction of the knee. The prime emphasis in the majority of the literature is given to surgical details of quadriceps graft harvesting and outcome of cruciate ligament reconstruction. There is less discussion about donor site morbidity in CQT graft, and it is less frequent as compared to that in bone patellar tendon bone graft. We report an extremely unusual case of late quadriceps tendon rupture at the donor site following anterior cruciate ligament reconstruction using CQT graft. PMID:26475883

  6. Anatomical study for an updated comprehension of clubfoot. Part II: Ligaments, tendons and muscles

    PubMed Central

    Anderhuber, Friedrich; Haldi-Brändle, Verena; Exner, Gerhard Ulrich

    2007-01-01

    Purpose The aim of our study was to evaluate the pathological anatomy of the ligaments, tendons and muscles in clubfeet, and to show whether the dysbalance of shortened and elongated structures is an adaptive process or a primary factor inducing the misshaped bones and cartilagines. Methods Surgical exposure was performed on seven idiopathic clubfeet specimens, aborted between the 25th and 37th week of gestation and compared to two normal feet (27th and 36th week of gestation). Results The medial stabilisation system of the foot was found shortened, but all ligaments could be dissected. On the lateral side, the calcaneofibular ligament in particular was both ‘shortened’ and ‘elongated’, depending on the course of the fibres to the axis of motion in the subtalar and talocalcaneonavicular joint. The main difference to the normal feet was found in the thickened tendon of the tibialis posterior forming a bulbus before dividing into fascicules. Conclusions We presume the ossification disturbance of the calcaneus to be the primary fault. This disturbance will influence the reduction of the varus position, so ligaments and tendons will be conformed to the misshaped bones. PMID:19308510

  7. Fibroma of the tendon sheath--a rare hand tumor following repetitive trauma to the palm.

    PubMed

    Yousaf, Muhammad

    2014-01-01

    Fibroma of the tendon sheath (FTS) is a rare, benign, soft tissue lesion. Clinically, FTS presents similarly to the more common giant cell tumour of the tendon sheath. It can be distinguished histologically by the lack of giant cells, foamy histiocytes and synovial cells. The author presents a case of FTS involving the flexor tendon to the fourth metacarpal following repetitive trauma. A 42 year old man presented with a three year history of painless mass in the right palm that had increased in size and became painful recently. Examination demonstrated 6 x 4 cm firm, nodular, superficial mass that was adherent to the underlying structures. Radiographs revealed soft tissue mass. Ultrasound showed a solid heterogeneous mass and the MRI demonstrated that the mass cantered predominantly at the mid and distal portion of fourth metacarpal. Fine Needle Aspiration Cytology was inconclusive. The patient underwent excisional biopsy of the lesion showing lobulated lesion closely resembling hyalinized collagen. Neither vascular proliferations, necrosis, nor mitoses were observed. A diagnosis of FTS was made. The case report provided an additional rare case to literature of a FTS and highlights the need to consider this entity in the differential diagnosis of any soft tissue lesion in the hand after repetitive trauma. Two months later the patient demonstrated full range of movements in the hand. PMID:25603689

  8. Monitoring tissue formation and organization of engineered tendon by optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Bagnaninchi, P. O.; Yang, Y.; Maffulli, N.; Wang, R. K.; El Haj, A.

    2006-02-01

    The uniaxial orientation and bundle formation of collagen fibres determine the mechanical properties of tendons. Thus the particular challenge of tendon tissue engineering is to build the tissue with a highly organized structure of collagen fibres. Ultimately the engineered construct will be used as autologous grafts in tendon surgery, withstanding physiological loading. We grew pig tenocytes in porous chitosan scaffolds with multiple microchannels of 250-500 ?m. The cell proliferation and production of extra-cellular matrix (ECM) within the scaffolds have been successfully monitored by Optical Coherence Tomography (OCT), a bench-top OCT system equipped with a broadband light source centred at 1300 nm. Under sterile condition, the measurements were performed on-line and in a non-destructive manner. In addition, a novel method based on OCT imaging, which calculates the occupation ratio of the microchannel derived from the scattered intensity has been developed. It is confirmed that the occupation ratio is correlated to cell proliferation and ECM production in the scaffolds. Thus this method has been utilised to assess the effect of different culture conditions on the tissue formation. The use of a perfusion bioreactor has resulted in a significantly (p<1e -3) higher cell proliferation and matrix production.

  9. Exploring the role of hypercholesterolemia in tendon health and repair.

    PubMed

    Hast, Michael W; Abboud, Joseph A; Soslowsky, Louis J

    2014-07-01

    High cholesterol remains a significant healthcare problem, as more than 13% of adults in the U.S. are affected by hypercholesterolemia. The detrimental effects the disease has on cardiovascular health are well-documented, but the effects on the musculoskeletal system, and more specifically on tendons, have not been thoroughly examined. This paper provides an overview of work performed in our lab with various animal models to elucidate the relationship between high cholesterol and tendon biomechanical integrity and ability to heal. These studies highlight the complexity of relationships between multiple factors that influence tendon biomechanics, and it has offered a better understanding of the implications of high cholesterol on healthy and healing tendons. PMID:25489542

  10. Exploring the role of hypercholesterolemia in tendon health and repair

    PubMed Central

    Hast, Michael W.; Abboud, Joseph A.; Soslowsky, Louis J.

    2014-01-01

    Summary High cholesterol remains a significant healthcare problem, as more than 13% of adults in the U.S. are affected by hypercholesterolemia. The detrimental effects the disease has on cardiovascular health are well-documented, but the effects on the musculoskeletal system, and more specifically on tendons, have not been thoroughly examined. This paper provides an overview of work performed in our lab with various animal models to elucidate the relationship between high cholesterol and tendon biomechanical integrity and ability to heal. These studies highlight the complexity of relationships between multiple factors that influence tendon biomechanics, and it has offered a better understanding of the implications of high cholesterol on healthy and healing tendons. PMID:25489542

  11. Suture techniques for tendon repair; a comparative review

    PubMed Central

    Rawson, Shelley; Cartmell, Sarah; Wong, Jason

    2013-01-01

    Summary Over the past five decades we have seen numerous iterations of suture repair methods for tendon. The pursuit of the ultimate repair has led to many repair methods being described. This comprehensive compilation of the suture repair techniques will describe the factors that affect repair success, including repair strength, gapping resistance, glide and rehabilitation. Different approaches to rejoining severed tendons will be critiqued on their biomechanical ability to improve tendon repair strength, maintaining glide, reducing tendon damage, and minimising adhesion formation. It is important to highlight how the suture repairs have evolved and improved but also review how they may contribute to their own trauma. The apparent paradox between providing mechanical strength and minimising adhesions require refinements in the field to improve on functional outcomes. PMID:24367784

  12. 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.

  13. 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 polyester reinforced medical grade silicone elastomer intended for use in the surgical reconstruction of...

  14. 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...

  15. 21 CFR 888.3025 - Passive tendon prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) 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...

  16. 21 CFR 888.3025 - Passive tendon prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...) 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...

  17. 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...

  18. Botox as an adjuvant to tendon transfer for foot drop.

    PubMed

    Eckel, Tobin T; Nunley, James A

    2013-01-01

    The authors' hypothesis was that weakening the gastrocnemius muscle at the time of tendon transfer will reduce the risk of rupture and facilitate faster rehabilitation with increased active dorsiflexion and improved overall outcome, because the transferred tendon is spared the antagonistic effect of the gastrocnemius during the early recovery period. A retrospective chart review identified 12 patients who underwent a tibialis posterior tendon (PTT) transfer with gastrocnemius Botox injection for foot drop. All statistical analyses were conducted using SAS version 9.2 (SAS Institute, Inc., Cary, North Carolina). There were no failures or tendon ruptures. All patients had zero dorsiflexion (DF) strength preoperatively, and those with DF strength documented postoperatively had a mean DF strength at final clinical evaluation of 3.9 (p < .001) with a mean active DF of 4°. It was concluded that gastrocnemius chemodenervation with Botox at the time of PTT transfer is a safe and effective means of restoring active dorsiflexion. PMID:24063800

  19. Repair of patellar tendon rupture using suture anchors.

    PubMed

    Bushnell, Brandon D; Tennant, Joshua N; Rubright, James H; Creighton, R Alexander

    2008-04-01

    Acute isolated rupture of the patellar tendon traditionally has been repaired via transpatellar suture tunnels. This retrospective study evaluated the demographics and epidemiology of this injury as well as the effectiveness and complication rates of our suture anchor technique. Between 1993 and 2005, a total of 82 cases of patellar tendon disruption in 71 patients were repaired. Fourteen cases involved basic primary repair with suture anchors of an acute isolated rupture of the patellar tendon and had an average follow-up of 29 months (range: 3-112 months). There were 3 (21%) failures of repair. The remaining 11 patients had excellent range of motion and strength and returned to their preoperative level of function. These results are comparable with other reports in the literature. The suture anchor technique thus represents a viable option for repair of patellar tendon ruptures and should be investigated further with a randomized, controlled trial. PMID:18500063

  20. Three-dimensional study of pectoralis major muscle and tendon architecture.

    PubMed

    Fung, Lillia; Wong, Brian; Ravichandiran, Kajeandra; Agur, Anne; Rindlisbacher, Tim; Elmaraghy, Amr

    2009-05-01

    A thorough understanding of the normal structural anatomy of the pectoralis major (PM) is of paramount importance in the planning of PM tendon transfers or repairs following traumatic PM tears. However, there is little consensus regarding the complex musculotendinous architecture of the PM in the anatomic or surgical literature. The purpose of this study is to model and quantify the three-dimensional architecture of the pectoralis muscle and tendon. Eleven formalin embalmed cadaveric specimens were examined: five (2M/3F) were serially dissected, digitized, and modeled in 3D using Autodesk Maya; six (4M/2F) were dissected and photographed. The PM tendon consisted of longer anterior and shorter posterior layers that were continuous inferiorly. The muscle belly consisted of an architecturally uniform clavicular head (CH) and a segmented sternal head (SH) with 6-7 segments. The most inferior SH segment in all specimens was found to fold anteriorly forming a trough that cradled the inferior aspect of the adjacent superior segment. No twisting of either the PM muscle or tendon was noted. Within the CH, the fiber bundle lengths (FBL) were found to increase from superior to inferior, whereas the mean FBLs of SH were greatest in segments 3-5 found centrally. The mean lateral pennation angle was greater in the CH (29.4 +/- 6.9 degrees ) than in the SH (20.6 +/- 2.7 degrees ). The application of these findings could form the basis of future studies to optimize surgical planning and functional recovery of repair/reconstruction procedures. PMID:19291757

  1. Active control of coupled dynamic response of TLP hull and tendon

    SciTech Connect

    Yoshida, Koichiro; Suzuki, Hideyuki; Nam, D.; Hineno, Motohiro; Ishida, Shigeki

    1994-12-31

    This paper presents an active control of coupled dynamic responses of the hull and the tendon of TLP. In a deepwater TLP, the restoring force becomes smaller and the natural frequency of the system decreases with increasing water depth. There is a possibility that the dynamic response of tendon, which is induced by the hull motion, can be significant. Furthermore the motion of TLP due to wave drifting force can be comparable or larger than wave induced motion. This low-frequency response can be controlled by conventional DPS thrusters. The operability is improved and the tendon and the riser are protected from structural damage. The low-frequency motion is induced by small wave drifting force and can be controlled by small control force. The first order wave force is very large and control of this high-frequency response is not practical. The control method is optimal control and the low-frequency hull motion and the bending strain of the tendon are controlled. The high-frequency response is removed from the control system by low pass filters. The effectiveness of control is verified by experiment with a 1/100 scale model of JOIA (Japan Ocean Industries Association)-TLP. The hull motion is measured by an ultrasonic ranging sensor and the control force is generated by two thrusters built in the TLP model. Average control force required for the control is about 1/200 of the hull weight, which is slightly larger than the value of the conventional DPS thrust of a semi-submersible.

  2. Mechanical properties of the patellar tendon in adults and children.

    PubMed

    O'Brien, Thomas D; Reeves, Neil D; Baltzopoulos, Vasilios; Jones, David A; Maganaris, Constantinos N

    2010-04-19

    It is not currently known how the mechanical properties of human tendons change with maturation in the two sexes. To address this, the stiffness and Young's modulus of the patellar tendon were measured in men, women, boys and girls (each group, n=10). Patellar tendon force (F(pt)) was calculated from the measured joint moment during a ramped voluntary isometric knee extension contraction, the antagonist knee extensor muscle co-activation quantified from its electromyographical activity, and the patellar tendon moment arm measured from magnetic resonance images. Tendon elongation was imaged using the sagittal-plane ultrasound scans throughout the contraction. Tendon cross-sectional area was measured at rest from ultrasound scans in the transverse plane. Maximal F(pt) and tendon elongation were (mean+/-SE) 5453+/-307 N and 5+/-0.5 mm for men, 3877+/-307 N and 4.9+/-0.6 mm for women, 2017+/-170 N and 6.2+/-0.5 mm for boys and 2169+/-182 N and 5.9+/-0.7 mm for girls. In all groups, tendon stiffness and Young's modulus were examined at the level that corresponded to the maximal 30% of the weakest participant's F(pt) and stress, respectively; these were 925-1321 N and 11.5-16.5 MPa, respectively. Stiffness was 94% greater in men than boys and 84% greater in women than girls (p<0.01), with no differences between men and women, or boys and girls (men 1076+/-87 N/mm; women 1030+/-139 N/mm; boys 555+/-71 N/mm and girls 561.5+/-57.4 N/mm). Young's modulus was 99% greater in men than boys (p<0.01), and 66% greater in women than girls (p<0.05). There were no differences in modulus between men and women, or boys and girls (men 597+/-49 MPa; women 549+/-70 MPa; boys 255+/-42 MPa and girls 302+/-33 MPa). These findings indicate that the mechanical stiffness of tendon increases with maturation due to an increased Young's modulus and, in females due to a greater increase in tendon cross-sectional area than tendon length. PMID:20045111

  3. The re-attachment of tendon and ligament avulsions.

    PubMed

    Grant, I; Pandya, A; Mahaffey, P J

    2002-08-01

    This paper presents our experience of a new technique for the reattachment of tendons in the hand. A percutaneous Kirschner wire is fashioned into a hoop to support an intratendinous suture. This mechanism maintains continuous traction upon the avulsed tendon. The technique avoids extensive dissection of the fingertip and the direct application of pressure on the dorsal surface of the digit, which might cause skin breakdown. PMID:12162972

  4. Surgical management of isolated popliteus tendon injuries in paediatric patients.

    PubMed

    Liu, Joseph N; Rebolledo, Brian J; Warren, Russell F; Green, Daniel W

    2016-03-01

    Isolated popliteus avulsion injuries are a rare occurrence, especially in the skeletally immature population. Two cases of isolated popliteus tendon avulsion injuries in paediatric patients were identified and successfully managed with suture anchor reattachment of the avulsed fragment in the anatomic position. The objective of this case report is to raise awareness of orthopaedic surgeons to the rarely encountered isolated popliteus tendon injury that can occur in paediatric patients. Level of evidence Expert opinion, Level V. PMID:26856317

  5. Traumatic rupture of both peroneal longus and brevis tendons.

    PubMed

    Pelet, Stéphane; Saglini, Marco; Garofalo, Raffaele; Wettstein, Michael; Mouhsine, Elyazid

    2003-09-01

    Injuries of peroneal tendons are rare. Diagnosis of traumatic rupture is often late and presents as chronic ankle instability. A case of a complete traumatic rupture of both peroneal longus and brevis tendons with acute clinical and radiological diagnosis is presented. Surgical repair was performed by direct end-to-end suture on the 4th day after trauma, with excellent functional outcome at 1-year follow-up. PMID:14524524

  6. 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

  7. 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. PMID:23730085

  8. 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

  9. 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. PMID:21625053

  10. Posterior Tibialis Tendon Dysfunction: Overview of Evaluation and Management.

    PubMed

    Yao, Kaihan; Yang, Timothy Xianyi; Yew, Wei Ping

    2015-06-01

    EDUCATIONAL OBJECTIVES As a result of reading this article, physicians should be able to: 1. Recognize posterior tibialis tendon dysfunction and begin to include it in differential diagnoses. 2. Recall the basic anatomy and pathology of the posterior tibialis tendon. 3. Assess a patient for posterior tibialis tendon dysfunction with the appropriate investigations and stratify the severity of the condition. 4. Develop and formulate a treatment plan for a patient with posterior tibialis tendon dysfunction. The posterior tibialis is a muscle in the deep posterior compartment of the calf that plays several key roles in the ankle and foot. Posterior tibialis tendon dysfunction is a complex but common and debilitating condition. Degenerative, inflammatory, functional, and traumatic etiologies have all been proposed. Despite being the leading cause of acquired flatfoot, it is often not recognized early enough. Knowledge of the anatomical considerations and etiology of posterior tibialis tendon dysfunction, as well as key concepts in its evaluation and management, will allow health care professionals to develop appropriate intervention strategies to prevent further development of flatfoot deformities. PMID:26091214

  11. Chondrogenic differentiation and lubricin expression of caprine infraspinatus tendon cells.

    PubMed

    Funakoshi, Tadanao; Spector, Myron

    2010-06-01

    Reparative strategies for the treatment of injuries to tendons, including those of the rotator cuff of the shoulder, need to address the formation of the cartilage which serves as the attachment apparatus to bone and which forms at regions undergoing compressive loading. Moreover, recent work indicates that cells employed for rotator cuff repair may need to synthesize a lubricating glycoprotein, lubricin, which has recently been found to play a role in tendon tribology. The objective of the present study was to investigate the chondrogenic differentiation and lubricin expression of caprine infraspinatus tendon cells in monolayer and three-dimensional culture, and to compare the behavior with bone marrow-derived mesenchymal stem cells (MSCs). The results demonstrated that while tendon cells in various media, including chondrogenic medium, expressed lubricin, virtually none of the MSCs synthesized this important lubricating molecule. Also of interest was that the cartilage formation capacity of the tendon cells grown in pellet culture in chondrogenic medium was comparable with MSCs. These data inform the use of tendon cells for rotator cuff repair, including for fibrocartilaginous zones. PMID:20058273

  12. Tendon Tissue Engineering: Progress, Challenges, and Translation to the Clinic

    PubMed Central

    Shearn, Jason T.; Kinneberg, Kirsten R.C.; Dyment, Nathaniel A.; Galloway, Marc T.; Kenter, Keith; Wylie, Christopher; Butler, David L.

    2013-01-01

    The tissue engineering field has made great strides in understanding how different aspects of tissue engineered constructs (TECs) and the culture process affect final tendon repair. However, there remain significant challenges in developing strategies that will lead to a clinically effective and commercially successful product. In an effort to increase repair quality, a better understanding of normal development, and how it differs from adult tendon healing, may provide strategies to improve tissue engineering. As tendon tissue engineering continues to improve, the field needs to employ more clinically relevant models of tendon injury such as degenerative tendons. We need to translate successes to larger animal models to begin exploring the clinical implications of our treatments. By advancing the models used to validate our TECs, we can help convince our toughest customer, the surgeon, that our products will be clinically efficacious. As we address these challenges in musculoskeletal tissue engineering, the field still needs to address the commercialization of products developed in the laboratory. TEC commercialization faces numerous challenges because each injury and patient is unique. This review aims to provide tissue engineers with a summary of important issues related to engineering tendon repairs and potential strategies for producing clinically successful products. PMID:21625053

  13. 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. PMID:22244070

  14. Human Achilles tendon glycation and function in diabetes.

    PubMed

    Couppé, Christian; Svensson, Rene Brüggebusch; Kongsgaard, Mads; Kovanen, Vuokko; Grosset, Jean-Francois; Snorgaard, Ole; Bencke, Jesper; Larsen, Jytte Overgaard; Bandholm, Thomas; Christensen, Tomas Møller; Boesen, Anders; Helmark, Ida Carøe; Aagaard, Per; Kjaer, Michael; Magnusson, Stig Peter

    2016-01-15

    Diabetic patients have an increased risk of foot ulcers, and glycation of collagen may increase tissue stiffness. We hypothesized that the level of glycemic control (glycation) may affect Achilles tendon stiffness, which can influence gait pattern. We therefore investigated the relationship between collagen glycation, Achilles tendon stiffness parameters, and plantar pressure in poorly (n = 22) and well (n = 22) controlled diabetic patients, including healthy age-matched (45-70 yr) controls (n = 11). There were no differences in any of the outcome parameters (collagen cross-linking or tendon stiffness) between patients with well-controlled and poorly controlled diabetes. The overall effect of diabetes was explored by collapsing the diabetes groups (DB) compared with the controls. Skin collagen cross-linking lysylpyridinoline, hydroxylysylpyridinoline (136%, 80%, P < 0.01) and pentosidine concentrations (55%, P < 0.05) were markedly greater in DB. Furthermore, Achilles tendon material stiffness was higher in DB (54%, P < 0.01). Notably, DB also demonstrated higher forefoot/rearfoot peak-plantar-pressure ratio (33%, P < 0.01). Overall, Achilles tendon material stiffness and skin connective tissue cross-linking were greater in diabetic patients compared with controls. The higher foot pressure indicates that material stiffness of tendon and other tissue (e.g., skin and joint capsule) may influence foot gait. The difference in foot pressure distribution may contribute to the development of foot ulcers in diabetic patients. PMID:26542519

  15. [Arthroscopic repair of partial subcapularis tendon lesions. Simplified approach].

    PubMed

    Pagán Conesa, Alejandro; Sánchez Martin, Alfredo; Aznar, Carlos Verdú

    2008-01-01

    We present a technical variation for arthroscopic subscapularis tendon repair. Sutures of isolated partial subscapularis tendon avulsions can be passed and fixed securely through an isolated anterolateral portal just over the rotator interval (mono-tunnel technique). Primarily a shoulder free of fixation devices is needed. Patient on a beach chair position or lateral decubitus without traction is advised. The best view can be obtained from a posterior portal with the shoulder on 75 degrees forward elevation and 90 degrees medial rotation. In a shoulder 30 degrees adducted at a good view can be also obtained from the antero-lateral portal. This working portal alone allows joint and tendon inspection, introduction of round burrs and devices needed for working on bone bed receptor. A titanium anchor of 5 mm with doubled non-absorbable suture is used, it can be passed through tendon with the Artropierce and an all-inside arthroscopic knot tying is done by just one tunnel thus minimizing the potential of injury of the coracohumeral ligament complex. This technique allows the surgeon to perform subscapularis tendon repair easily with reproducible good results in 7 cases of isolated partial tendon avulsions in this serie. We also recommend it in combination with other rotator cuff repairing techniques. PMID:18979983

  16. 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.

  17. Fibrocartilage in tendons and ligaments — an adaptation to compressive load

    PubMed Central

    BENJAMIN, M.; RALPHS, J. R.

    1998-01-01

    Where tendons and ligaments are subject to compression, they are frequently fibrocartilaginous. This occurs at 2 principal sites: where tendons (and sometimes ligaments) wrap around bony or fibrous pulleys, and in the region where they attach to bone, i.e. at their entheses. Wrap-around tendons are most characteristic of the limbs and are commonly wider at their point of bony contact so that the pressure is reduced. The most fibrocartilaginous tendons are heavily loaded and permanently bent around their pulleys. There is often pronounced interweaving of collagen fibres that prevents the tendons from splaying apart under compression. The fibrocartilage can be located within fascicles, or in endo- or epitenon (where it may protect blood vessels from compression or allow fascicles to slide). Fibrocartilage cells are commonly packed with intermediate filaments which could be involved in transducing mechanical load. The ECM often contains aggrecan which allows the tendon to imbibe water and withstand compression. Type II collagen may also be present, particularly in tendons that are heavily loaded. Fibrocartilage is a dynamic tissue that disappears when the tendons are rerouted surgically and can be maintained in vitro when discs of tendon are compressed. Finite element analyses provide a good correlation between its distribution and levels of compressive stress, but at some locations fibrocartilage is a sign of pathology. Enthesis fibrocartilage is most typical of tendons or ligaments that attach to the epiphyses of long bones where it may also be accompanied by sesamoid and periosteal fibrocartilages. It is characteristic of sites where the angle of attachment changes throughout the range of joint movement and it reduces wear and tear by dissipating stress concentration at the bony interface. There is a good correlation between the distribution of fibrocartilage within an enthesis and the levels of compressive stress. The complex interlocking between calcified fibrocartilage and bone contributes to the mechanical strength of the enthesis and cartilage-like molecules (e.g. aggrecan and type II collagen) in the ECM contribute to its ability to withstand compression. Pathological changes are common and are known as enthesopathies. PMID:10029181

  18. Relative contributions of mechanical degradation, enzymatic degradation, and repair of the extracellular matrix on the response of tendons when subjected to under- and over- mechanical stimulations in vitro.

    PubMed

    Cousineau-Pelletier, Paule; Langelier, Eve

    2010-02-01

    Tendon response to mechanical loading results in either homeostasis, improvement, or degeneration of tissue condition. In an effort to better understand the development of tendinopathies, this study investigated the mechanical and structural responses of tendons subjected to under- and over-stimulations (1.2% and 1.8% strain respectively, 1 Hz). The objective was to examine three sub-processes of tendon response: mechanical degradation, enzymatic degradation, and repair of the extracellular matrix. We subjected rat tail tendons to a 10-day stimulation protocol with four periods of 6 h each day: 30 min of stimulation and 5 h 30 min of rest. To investigate the contribution of the three sub-processes, we controlled the contribution of the cells through variations in the nutrient and protease inhibitor content in the in vitro solutions. Using nondestructive cyclic tests, we evaluated the daily changes in the peak stress. To assess structural changes, we carried out microscopic analyses at the end of the study period. We observed that the relative contributions of the sub-processes differed according to the stimulation amplitude. With over-stimulation of tendons immersed in DMEM, we succeeded in reducing enzymatic degradation and increasing peak stress. In under-stimulation, the addition of protease inhibitors was required to obtain the same result. PMID:19725106

  19. Patellar Tendon–Trochlear Groove Angle Measurement

    PubMed Central

    Hinckel, Betina B.; Gobbi, Riccardo G.; Kihara Filho, Eduardo N.; Demange, Marco K.; Pécora, José Ricardo; Camanho, Gilberto Luis

    2015-01-01

    Background: The tibial tubercle–trochlear groove (TT-TG) is used as the gold standard for patellofemoral malalignment. Purpose: To assess 3 patellar tendon–trochlear groove (PT-TG) angle measurement techniques and the PT-TG distance measurement (tendinous cartilaginous TT-TG) as predictors of patellar instability. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: Three PT-TG angle measurements and the PT-TG distance were measured in 82 participants with patellar instability and 100 controls using magnetic resonance imaging (MRI). Measurement landmarks were the line tangent to the posterior femoral condyles, the deepest point of the trochlea, the transepicondylar line, and the patellar tendon center. All measurements were recorded once by 1 examiner, and the measurements were recorded twice by 2 examiners in a random group of 100 knees. Mean values and standard deviations (SDs) were obtained. Normality cutoff values were defined as 2 and 3 SDs above the mean in the control group. The sensitivity, specificity, and positive likelihood ratio (LR+) were calculated. Inter- and intrarater reliability were assessed based on the intraclass correlation coefficient (ICC). Results: The measurements from the patellar instability and control groups, respectively, for angle 1 (16.4° and 8.4°), angle 2 (31° and 15.6°), angle 3 (30.8° and 15.7°), PT-TG distance (14.5 and 8.4 mm), and patellar tilt (21.1° and 7.5°) were significantly different (P < .05). The angle measurements showed greater sensitivity, specificity, and LR+ than the PT-TG distance. Inter- and intrarater ICC values were >0.95 for all measurements. Conclusion: The PT-TG angle and the PT-TG distance are reliable and are different between the patellar instability and control groups. PT-TG angles are more closely associated with patellar instability than PT-TG distance. Clinical Relevance: PT-TG angle measurements show high reliability and association with patellar instability and can aid in the assessment of extensor mechanism malalignment. A more sensitive and specific evaluation of extensor mechanism malalignment can improve patient care by preventing both redislocation and abnormal tracking of overlooked malalignment and complications of unnecessary tibial tuberosity medialization. PMID:26535396

  20. Dielectric relaxation in slightly hydrated bovine tendon collagen

    NASA Astrophysics Data System (ADS)

    Zahra Rizvi, Tasneem; Abdullah Khan, Muhammad

    2007-01-01

    With an aim to reveal the mechanism of water-protein interaction from the dielectric response of a model fibrous protein, the dielectric constant ?' and loss factor ?'' have been measured in air dried and vacuum dried samples of bovine tendon collagen in the frequency range 30 Hz-3 MHz and temperature range 30-200 °C. An anomalous low frequency dispersion (LFD) and an intermediate frequency strong ?-dispersion peak were the two main dielectric responses observed in the air dried sample. The LFD followed the fractional power law of frequency while the ?-dispersion conformed to the Cole-Cole modified Debye equation. These dispersions, respectively, have been attributed to percolation of protons between and within the clusters of hydrogen bonded water molecules bound to polar or ionizable protein components. In the vacuum dried sample, however, a very weak high frequency ?2-dispersion peak was observed, which was hidden below the strong ?-dispersion in the air dried sample. This peak may be attributed to reorientation of polar components of the collagen molecule. Temperature dependence of the dielectric data shows release of bound water as a four-step process with discrete peaks at 50, 90, 125 and 160 °C. These peaks have been attributed to the onset of the release of adsorbed surface water, water bound to exposed polar sites, water bound to internal polar sites and very strongly bound structural water, respectively.

  1. 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.

  2. Development of the shields for tendon injury repair using polyvinyl alcohol--hydrogel ( PVA-H).

    PubMed

    Kobayashi, M; Toguchida, J; Oka, M

    2001-01-01

    In recent years, marked advances have been made in repair techniques for tendon injury, but the treatment of finger flexor tendon injury is still one of the most difficult and important problems in the orthopedic field. The main problem in tendon repair is adhesion between the tendon and surrounding tissue. To prevent this adhesion and achieve tendon union, we developed adhesion preventive shields for tendon repair using polyvinyl alcohol hydrogel ( PVA-H) with 90% water content, and carried out an implant experiment using the deep flexor tendon of the third toe of domestic fowl. Injured tendons shielded with PVA-H showed union at about 3 weeks after the operation without adhesion to the surrounding tissue and good function such as gliding and range of motion. Neither breakage of the PVA-H shield itself nor infection, nor degeneration in the surrounding tissue were observed. These results confirmed that the tendon itself has repair ability, and the tendon is regenerated by synovial nutrition through PVA-H. High water content PVA-H may have clinically potential and be applicable to adhesion-preventive shields for tendon repair. However, re-rupture was observed, probably due to accidental tendon injury at an early period after the operation. In some cases, tendon immobilization methods to prevent re-rupture might be necessary. PMID:11410891

  3. Contribution of biomechanics to management of ligament and tendon injuries.

    PubMed

    Woo, Savio L Y; Fisher, Matthew B; Feola, Andrew J

    2008-03-01

    The contribution of biomechanics to the advancement of management of ligament and tendon injuries has been significant. Thanks to Professor Y.C. Fung's writing and guidance, our field of research has done fundamental work on anatomy and biology of ligaments and tendons, developed methods to accurately determine mechanical properties, identified various experimental factors which could change the outcome measurements as well as examined biological factors that change tissue properties in-vivo. Professor Fung also gave us his quasi-linear viscoelastic theory for soft tissues so that the time and history dependent properties of ligaments and tendons could be properly described. We have further adopted Professor Fung's eight steps on methods of approach for biomechanical investigation to understand as well as enhance the treatment of ligament and tendon injuries during work or sports related activities. Examples on how to better treat the tears of the medial collateral ligament of the knee, as well as how to improve reconstruction procedures for the anterior cruciate ligament are presented in detail. Currently the use of functional tissue engineering for ligament and tendon healing is a topic of great interest. Here the use of biological scaffolds, such as porcine small intestinal submucosa, has shown promise. For the last 35 to 40 years, the field of biomechanics has made great strides in the treatment of ligament and tendon injuries, and many patients have benefited. The future is even brighter because of what has been done properly in the past. Exciting advances can be made in the field of tissue engineering through novel in-vitro culture and bioscaffold fabrication techniques. Recent technology can also allow the collection of in-vivo data so that ligament and tendon injuries can be better understood. Yet, solving new and more complex problems must still follow the stepwise methods of approach as taught by Professor Fung. PMID:18524246

  4. Quantitative ultrasound (QUS) assessment of tissue properties for Achilles tendons

    NASA Astrophysics Data System (ADS)

    Du, Yi-Chun; Chen, Yung-Fu; Chen, Pei-Jarn; Lin, Yu-Ching; Chen, Tainsong; Lin, Chii-Jeng

    2007-09-01

    Quantitative ultrasound (QUS) techniques have recently been widely applied for the characterization of tissues. For example, they can be used for the quantification of Achilles tendon properties based on the broadband ultrasound attenuation (BUA) and the speed of sound (SOS) when the ultrasound wave passes through the tissues. This study is to develop an integrated system to investigate the properties of Achilles tendons using QUS images from UBIS 5000 (DMS, Montpellier, France) and B-mode ultrasound images from HDI 5000 (ATL, Ultramark, USA). Subjects including young (32 females and 17 males; mean age: 23.7 ± 2.0) and middle-aged groups (8 female and 8 males; mean age: 47.3 ± 8.5 s) were recruited and tested for this study. Only subjects who did not exercise regularly and had no record of tendon injury were studied. The results show that the BUA is significantly higher for the young group (45.2 ± 1.6 dB MHz-1) than the middle-age group (40.5 ± 1.9 dB MHz-1), while the SOS is significantly lower for the young (1601.9 ± 11.2 ms-1) compared to the middle-aged (1624.1 ± 8.7 m s-1). On the other hand, the thicknesses of Achilles tendons for both groups (young: 4.31 ± 0.23 mm; middle age: 4.24 ± 0.23 mm) are very similar. For one patient who had an Achilles tendon lengthening (ATL) surgery, the thickness of the Achilles tendon increased from 4 mm to 4.33 mm after the surgery. In addition, the BUA increased by about 7.2% while the SOS decreased by about 0.6%. In conclusion, noninvasive ultrasonic assessment of Achilles tendons is useful for assisting clinical diagnosis and for the evaluation of a therapeutic regimen.

  5. Repopulation of Intrasynovial Flexor Tendon Allograft with Bone Marrow Stromal Cells: An Ex Vivo Model

    PubMed Central

    Amadio, Peter C.; Thoreson, Andrew R.; An, Kai-Nan

    2014-01-01

    Purpose: Delayed healing is a common problem whenever tendon allografts are used for tendon or ligament reconstruction. Repopulating the allograft with host cells may accelerate tendon regeneration, but cell penetration into the allograft tendon is limited. Processing the tendon surface with slits that guide cells into the allograft substrate may improve healing. The purpose of this study was to describe a surface modification of allograft tendon that includes slits to aid cell repopulation and lubrication to enhance tendon gliding. Methods: Canine flexor digitorum profundus tendons were used for this study. Cyclic gliding resistance was measured over 1000 cycles. Tensile stiffness was assessed for normal tendon, tendon decellularized with trypsin and Triton X-100 (decellularized group), tendon decellularized and perforated with multiple slits (MS group) and tendon decellularized, perforated with slits and treated with a carbodiimide-derivatized hyaluronic acid and gelatin (cd-HA-gelatin) surface modification (MS-SM group). To assess tendon repopulation, bone marrow stromal cells (BMSCs) were used in the decellularized and MS groups. DNA concentration and histology were evaluated and compared to normal tendons and nonseeded decellularized tendons. Results: The gliding resistance of the decellularized and MS groups was significantly higher compared with the normal group. There was no significant difference in gliding resistance between the decellularized and MS group. Gliding resistance of the normal group and MS-SM group was not significantly different. The Young's modulus was not significantly different among the four groups. The DNA concentration in the MS group was significantly lower than in normal tendons, but significantly higher than in decellularized tendons, with or without BMSCs. Viable BMSCs were found in the slits after 2 weeks in tissue culture. Conclusions: Tendon slits can successfully harbor BMSCs without compromising their survival and without changing tendon stiffness. Surface modification restores normal gliding function to the slit tendon. Clinical Relevance: A multislit tendon reseeded with BMSCs, with a surface treatment applied to restore gliding properties, may potentially promote tendon revitalization and accelerate healing for tendon or ligament reconstruction applications. PMID:24024566

  6. Evaluation of mean echogenicity of tendons and ligaments of the metacarpal region in neonatal foals: A preliminary study.

    PubMed

    Spinella, G; Loprete, G; Castagnetti, C; Musella, V; Antonelli, C; Vilar, J M; Britti, D; Capitani, O; Valentini, S

    2015-08-01

    The aims of this research were to evaluate mean echogenicity (ME) of the deep and superficial digital flexor tendons (DDFT and SDFT), the interosseous muscle (IM), and the accessory ligament of the deep digital flexor tendon (ALDDFT) of the metacarpal region in neonatal foals, and determine the effect of sex, side and body weight on this quantitative ultrasonographic evaluation. Thirteen orthopedically sound neonatal foals were examined. Four areas of study (1A, 1B, 2A, 2B) were identified. Transverse scans of the DDFT, SDFT, IM and ALDDFT were obtained, recorded, and analyzed. The most echogenic structures were the ALDDFT and DDFT, while the SDFT was significantly less echogenic than all other structures (P<0.05). No influence of sex, forelimb, or body weight was observed. The echogenicity of the tenodesmic structures of foals partially overlapped that reported in the metacarpal region in adult horses, except for IM. PMID:26267082

  7. 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 thick (99%CI and SD = 0.95), as opposed to 2.09 ± 0.24 mm (99%CI, SD = 0.47) in the patients in which the MRI revealed no Achilles tendon diseases; this difference in thickness of 1.29 ± 0.57 mm (99%CI) was statistically significant (P < 0.001). In the group of 27/52 patients with tendinopathies, the PF was more than 4.5 mm thick in 5, i.e. they exceeded the threshold for a diagnosis of plantar fasciitis. None of the other 25/52 paitents had a PF more than 4 mm thick. There was a statistically significant correlation between the thicknesses of the PF and the paratenon. These findings suggest that the plantar fascia has a role not only in supporting the longitudinal arch of the foot, but also in its proprioception and peripheral motor coordination. Its relationship with the paratenon of the Achilles tendon is consistent with the idea of triceps surae structures being involved in the PF pathology, so their rehabilitation can be considered appropriate. Finally, the high concentration of hyaluronan in the PF points to the feasibility of using hyaluronan injections in the fascia to treat plantar fasciitis. PMID:24028383

  8. Giant Cell Tumor of Tendon Sheath

    PubMed Central

    Briët, Jan Paul; Becker, Stéphanie JE; Oosterhoff, Thijs CH; Ring, David

    2015-01-01

    Background: Giant cell tumor of tendon sheath (GCTTS) is often thought of as a volar finger mass. We hypothesized that GCTTS are equally common on the dorsal and volar aspects of the hand. In addition, we hypothesized that there are no factors associated with the location (volar versus dorsal) and largest measured dimension of a GCTTS. Methods: A total of 126 patients with a pathological diagnosis of a GCTTS of the hand or finger were reviewed. Basic demographic and GCTTS specific information was obtained. Bivariable analyses were used to assess predicting factors for location (volar or dorsal side) and largest measured diameter of a GCTTS. Results: Seventy-two tumors (57%) were on the volar side of the hand, 47 (37%) were dorsal, 6 (4.8%) were both dorsal and volar, and one was midaxial (0.79%). The most common site of a GCTTS was the index finger (30%). There were no factors significantly associated with the location (volar or dorsal, n=119) of the GCTTS. There were also no factors significantly associated with a larger diameter of a GCTTS. Conclusions: A GCTTS was more frequently seen on the volar aspect of the hand. No significant factors associated with the location or an increased size of a GCTTS were found in this study. PMID:25692164

  9. Ultrasound elastography for imaging tendons and muscles

    PubMed Central

    2012-01-01

    Ultrasound elastography is a recently developed ultrasound-based method which allows the qualitative or quantitative evaluation of the mechanical properties of tissue. Strain (compression) ultrasound elastography is the commonest technique performed by applying mild compression with the hand-held transducer to create real-time strain distribution maps, which are color-coded and superimposed on the B-mode images. There is increasing evidence that ultrasound elastography can be used in the investigation of muscle, tendon and soft tissue disease in the clinical practice, as a supplementary tool to conventional ultrasound examination. Based on preliminary data, potential clinical applications include early diagnosis, staging, and guiding interventions musculotendinous and neuromuscular disease as well as monitoring disease during rehabilitation. Ultrasound elastography could also be used for research into the biomechanics and pathophysiology of musculotendinous disease. Despite the great interest in the technique, there is still limited evidence in the literature and there are several technical issues which limit the reproducibility of the method, including differences in quantification methods, artefacts, limitations and variation in the application of the technique by different users. This review presents the published evidence on musculoskeletal applications of strain elastography, discusses the technical issues and future perspectives of this method and emphasizes the need for standardization and further research.

  10. 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. PMID:24584568

  11. 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. PMID:22179930

  12. The vasculature and its role in the damaged and healing tendon.

    PubMed

    Fenwick, Steven A; Hazleman, Brian L; Riley, Graham P

    2002-01-01

    Tendon pathology has many manifestations, from spontaneous rupture to chronic tendinitis or tendinosis; the etiology and pathology of each are very different, and poorly understood. Tendon is a comparatively poorly vascularised tissue that relies heavily upon synovial fluid diffusion to provide nutrition. During tendon injury, as with damage to any tissue, there is a requirement for cell infiltration from the blood system to provide the necessary reparative factors for tissue healing. We describe in this review the response of the vasculature to tendon damage in a number of forms, and how and when the revascularisation or neovascularisation process occurs. We also include a section on the revascularisation of tendon during its use as a tendon graft in both ligament reconstruction and tendon-tendon grafting. PMID:12106496

  13. 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

  14. Editorial Commentary: Quadriceps Tendon Autograft Use for Anterior Cruciate Ligament Reconstruction Predicted to Increase.

    PubMed

    Lubowitz, James H

    2016-01-01

    Quadriceps tendon autograft is the least utilized choice for anterior cruciate ligament reconstruction, but use is expected to increase. Harvest of the full thickness of the distal quadriceps tendon is of concern, but morbidity seems low. PMID:26743412

  15. 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

  16. 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.

  17. Tendon-to-Bone Attachment: From Development to Maturity

    PubMed Central

    Zelzer, Elazar; Blitz, Einat; Killian, Megan L.; Thomopoulos, Stavros

    2014-01-01

    The attachment between tendon and bone occurs across a complex transitional tissue that minimizes stress concentrations and allows for load transfer between muscles and skeleton. This unique tissue cannot be reconstructed following injury, leading to high incidence of recurrent failure and stressing the need for new clinical approaches. This review describes the current understanding of the development and function of the attachment site between tendon and bone. The embryonic attachment unit, namely, the tip of the tendon and the bone eminence into which it is inserted, was recently shown to develop modularly from a unique population of Sox9- and Scx-positive cells, which are distinct from tendon fibroblasts and chondrocytes. The fate and differentiation of these cells is regulated by transforming growth factor beta and bone morphogenetic protein signaling, respectively. Muscle loads are then necessary for the tissue to mature and mineralize. Mineralization of the attachment unit, which occurs postnatally at most sites, is largely controlled by an Indian hedgehog/parathyroid hormone-related protein feedback loop. A number of fundamental questions regarding the development of this remarkable attachment system require further study. These relate to the signaling mechanism that facilitates the formation of an interface with a gradient of cellular and extracellular phenotypes, as well as to the interactions between tendon and bone at the point of attachment. PMID:24677726

  18. Cell therapies for tendons: old cell choice for modern innovation.

    PubMed

    Petrou, Ilias G; Grognuz, Anthony; Hirt-Burri, Nathalie; Raffoul, Wassim; Applegate, Lee Ann

    2014-01-01

    Although tissue engineering and cell therapies are becoming realistic approaches for medical therapeutics, it is likely that musculoskeletal applications will be among the first to benefit on a large scale. Cell sources for tissue engineering and cell therapies for tendon pathologies are reviewed with an emphasis on small defect tendon injuries as seen in the hand which could adapt well to injectable cell administration. Specifically, cell sources including tenocytes, tendon sheath fibroblasts, bone marrow or adipose-derived stem cells, amniotic cells, placenta cells and platelet-derivatives have been proposed to enhance tendon regeneration. The associated advantages and disadvantages for these different strategies will be discussed and evolving regulatory requirements for cellular therapies will also be addressed. Human progenitor tenocytes, along with their clinical cell banking potential, will be presented as an alternative cell source solution. Similar cell banking techniques have already been described with other progenitor cell types in the 1950's for vaccine production, and these "old" cell types incite potentially interesting therapeutic options that could be improved with modern innovation for tendon regeneration and repair. PMID:25102358

  19. Characterization and differentiation of equine tendon-derived progenitor cells.

    PubMed

    Lovati, A B; Corradetti, B; Lange Consiglio, A; Recordati, C; Bonacina, E; Bizzaro, D; Cremonesi, F

    2011-01-01

    Mesenchymal stem cells have been recently investigated for their potential use in regenerative medicine. Population of adult stem cells were recently identified in human and lab animal tendons, but no detailed investigations have been made in the equine species. The aim of our study is to identify a progenitor cell population from tendon tissue (TSPCs) in the horse superficial digital flexor tendon that are able to be highly clonogenic, to grow fast and to differentiate in different induced cell lineages as well as bone marrow derived progenitor cells (BM-MSCs). The hypothesis that TSPCs possess a mesenchymal stem cell behavior opens a new prospective for tendon regenerative medicine approaches. TSPCs were expanded more rapidly and showed higher plating efficiency when compared with BM-MSCs. Both cell lines expressed identical stem cell markers in vitro and they were able to differentiate towards osteogenic and adipogenic lineages as demonstrated with cytochemical staining and mRNA gene expression. TSPCs showed a positive but limited chondrogenic differentiation compared with BM-MSCs as demonstrated by histological and biochemical analyses. According to our results, equine TSPCs have high clonogenic properties and proliferating potential, they express stem cell markers and have the capability to be multipotent as well as BM-MSCs. These findings suggest that TSPCs may represent a good model for stem cell biology and could be useful for future tendon regenerative medicine investigations. PMID:22051173

  20. 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

  1. Correlation of remaining patellar tendon width with quadriceps strength after autogenous bone-patellar tendon-bone anterior cruciate ligament reconstruction.

    PubMed

    Shelbourne, K D; Rubinstein, R A; VanMeter, C D; McCarroll, J R; Rettig, A C

    1994-01-01

    One hundred twenty-one patients were prospectively studied to determine whether the different remaining patellar tendon widths after central 10-mm bone-patellar tendon-bone graft harvest influenced the rate and level of quadriceps strength achieved during rehabilitation. Size of the patellar tendon width, measured at the same location in each patient, ranged from 24 to 35 mm. For this study, patients were grouped according to their remaining tendon size into small (14 to 17 mm; mean, 15.8), medium (18 to 20 mm; mean, 19.2), and large (21 to 25 mm; mean, 22.5) widths. Postoperatively, the patient's isokinetic quadriceps scores were determined at 6 weeks, 3 months, 6 months, and 1 year. At 6 weeks, the small- and medium-width tendon groups were significantly weaker than the large-width tendon group. At 3 months, only the small-width tendon group continued to be significantly weaker than the large-width tendon group. At and beyond 6 months, no statistically significant differences were seen between remaining patellar tendon width groups and their isokinetic quadriceps scores. A constant-sized autogenous patellar tendon graft may be harvested for anterior cruciate ligament reconstruction without compromising ultimate postoperative quadriceps strength recovery. PMID:7856801

  2. Effects of lubricant and autologous bone marrow stromal cell augmentation on immobilized flexor tendon repairs.

    PubMed

    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?×?10(5) 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?tendons was higher than the treated tendons at 21 and 42 days (p?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. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:154-160, 2016. PMID:26177854

  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. PMID:23870541

  4. 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.

  5. 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.

  6. 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.

  7. Subcoracoid impingement and subscapularis tendon: is there any truth?

    PubMed

    Osti, Leonardo; Soldati, Francesco; Del Buono, Angelo; Massari, Leo

    2013-04-01

    Subcoracoid impingement and stenosis have been described related to anterior shoulder pain and subscapularis tendon tears, but the pathogenesis and related treatment of this condition has still not been explained properly. Variability of coracoid morphology has been described and both traumatic and iatrogenic factors can modify it. Some authors referred this to a primary narrow coracohumeral distance with different threshold values defined as increased risk factor for subscapularis and antero-superior RC tear; opposite theories stated that the stenosis is secondary to an anterosuperior translation of the humeral head toward the coracoid due to degenerative changes of the rotator cuff tendons. Limited coracoplasty can be performed when related risk factors are identified; however no clear consensus arises from specific literature review and extensive clinical and instrumental examination of the patient should be performed in order to identify specific risk factors for subscapularis tendon pathology and, subsequently, tailor the proper approach. PMID:23888292

  8. Subcoracoid impingement and subscapularis tendon: is there any truth?

    PubMed Central

    Osti, Leonardo; Soldati, Francesco; Del Buono, Angelo; Massari, Leo

    2013-01-01

    Summary Subcoracoid impingement and stenosis have been described related to anterior shoulder pain and subscapularis tendon tears, but the pathogenesis and related treatment of this condition has still not been explained properly. Variability of coracoid morphology has been described and both traumatic and iatrogenic factors can modify it. Some authors referred this to a primary narrow coracohumeral distance with different threshold values defined as increased risk factor for subscapularis and antero-superior RC tear; opposite theories stated that the stenosis is secondary to an anterosuperior translation of the humeral head toward the coracoid due to degenerative changes of the rotator cuff tendons. Limited coracoplasty can be performed when related risk factors are identified; however no clear consensus arises from specific literature review and extensive clinical and instrumental examination of the patient should be performed in order to identify specific risk factors for subscapularis tendon pathology and, subsequently, tailor the proper approach. PMID:23888292

  9. Posterior Tibial Tendon Dysfunction: An Overlooked Cause of Foot Deformity

    PubMed Central

    Bubra, Preet Singh; Keighley, Geffrey; Rateesh, Shruti; Carmody, David

    2015-01-01

    Posterior tibial tendon dysfunction is the most common cause of adult acquired flatfoot. Degenerative changes in this tendon, lead to pain and weakness and if not identified and treated will progress to deformity of the foot and degenerative changes in the surrounding joints. Patients will complain of medial foot pain, weakness, and a slowly progressive foot deformity. A “too many toes” sign may be present and patients will be unable to perform a single heal raise test. Investigations such X-ray, ultrasound and magnetic resonance imaging will help stage the disease and decide on management. The optimal manage may change based on the progression of deformity and stage of disease. Early identification and prompt initiation of treatment can halt progression of the disease. The purpose of this article is to examine the causes, signs, symptoms, examinations, investigations and treatment options for posterior tibial tendon dysfunction. PMID:25810985

  10. Irreducible Anteromedial Dislocation of Radial Head with Biceps Tendon Interposition.

    PubMed

    Climent-Peris, Vicente J; Sirera-Vercher, Josette; Sanz-Amaro, M Dolores

    2016-01-01

    The case presents an isolated irreducible anteromedial dislocation of radial head due to biceps tendon interposition on a 14-year-old female patient. After an unsuccessful closed reduction, a lateral approach of the left elbow was carried out through Kocher's interval. Given that no pathology was found on the radiohumeral joint, the approach was extended distally. This revealed that the biceps tendon was displaced laterally around the radial neck, preventing the reduction. Once the tendon was taken back to its anatomical position, the radial head reduction was performed successfully. The patient achieved a complete functional recovery. Possible injury mechanisms are discussed, as well as the importance of identifying such a rare injury. PMID:26925279

  11. Irreducible Anteromedial Dislocation of Radial Head with Biceps Tendon Interposition

    PubMed Central

    Climent-Peris, Vicente J.; Sirera-Vercher, Josette; Sanz-Amaro, M. Dolores

    2016-01-01

    The case presents an isolated irreducible anteromedial dislocation of radial head due to biceps tendon interposition on a 14-year-old female patient. After an unsuccessful closed reduction, a lateral approach of the left elbow was carried out through Kocher's interval. Given that no pathology was found on the radiohumeral joint, the approach was extended distally. This revealed that the biceps tendon was displaced laterally around the radial neck, preventing the reduction. Once the tendon was taken back to its anatomical position, the radial head reduction was performed successfully. The patient achieved a complete functional recovery. Possible injury mechanisms are discussed, as well as the importance of identifying such a rare injury. PMID:26925279

  12. Traumatic subluxation/dislocation of the peroneal tendons.

    PubMed

    Brage, M E; Hansen, S T

    1992-09-01

    Traumatic subluxation/dislocation of the peroneal tendons has been reported following a variety of sports-related activities. The peroneal musculature contracts reflexively during the injury and overcomes the restraining soft tissue. The tendons can then dislocate anteriorly from behind the distal fibula. Some patients have anatomical variations of the posterolateral ankle that predispose them to injury. If the physician is unaware of the injury, the diagnosis may be missed in the acute setting and can develop into a chronic, disabling condition. Treatment of the acute injury is controversial because advocates exist for both conservative and surgical therapies. The chronic, painful lesion should be treated operatively. A tremendous number of surgical procedures have been described for the treatment of chronic tendon dislocations. Choice of a surgical procedure depends upon the anatomy of the peroneal groove and the retinaculum, and the nature of the damage to the area. PMID:1427535

  13. Could Ossification of the Achilles Tendon Have a Hereditary Component?

    PubMed Central

    Cortbaoui, Chawki

    2013-01-01

    Ossification of the Achilles tendon (OTA) is an unusual clinical condition. It is characterized by the presence of an ossified mass within the fibrocartilaginous substance of the Achilles tendon. The etiology of the ossification of the Achilles tendon is unknown. Review of the literature suggests that its etiology is multifactorial. The major contributing factors are trauma and surgery with other minor causes such as systemic diseases, metabolic conditions, and infections. To our knowledge, no previous reports suggest any genetic/hereditary predisposition in OAT. We report 3 siblings who have OAT with no history of any of the aforementioned predisposing factors. Could OAT have a hereditary component as one of its etiologies? PMID:23738172

  14. 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. PMID:24362243

  15. 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. PMID:26337379

  16. Supraspinatus Intramuscular Calcified Hematoma or Necrosis Associated with Tendon Tear

    PubMed Central

    Lädermann, Alexandre; Genevay, Muriel; Abrassart, Sophie; Schwitzguébel, Adrien Jean-Pierre

    2015-01-01

    Introduction. Rotator cuff intramuscular calcification is a rare condition usually caused by heterotopic ossification and myositis ossificans. Case Presentation. We describe a patient with voluminous calcified mass entrapped in supraspinatus muscle associated with corresponding tendon tear. Histological examination corresponded to a calcified hematoma or necrosis. Patient was surgically managed with open excision of the calcified hematoma and rotator cuff arthroscopic repair. At 6 months, supraspinatus muscle was healed, and functional outcome was good. Discussion and Conclusion. We hypothesized that supraspinatus intramuscular calcified hematoma was responsible for mechanical stress on the tendon. This association has never been described. PMID:26380138

  17. 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

    2016-01-01

    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. PMID:26606262

  18. Biomechanical risk factors and flexor tendon frictional work in the cadaveric carpal tunnel.

    PubMed

    Kociolek, Aaron M; Tat, Jimmy; Keir, Peter J

    2015-02-01

    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. PMID:25553671

  19. Nonoperative management of a partial patellar tendon rupture after bone-patellar tendon-bone graft harvest for ACL reconstruction.

    PubMed

    Benner, Rodney W; Shelbourne, K Donald; Freeman, Heather

    2013-12-01

    This is a case report of a young athlete who sustained a partial tear of the patellar tendon after anterior cruciate ligament (ACL) reconstruction with a bone-patellar tendon-bone (BPTB) autograft. The injury, diagnostic workup, and decision-making process that lead to the choice of nonsurgical treatment are described. Furthermore, the rehabilitation process is described in detail. The patient returned to his previous level of sports activity and had a good clinical outcome as measured by range of motion, isokinetic quadriceps muscle strength testing, single leg hop testing, and the modified Noyes survey. In the absence of extensor mechanism incompetence or radiographic evidence of significant patella alta, partial ruptures of the patella tendon after ACL reconstruction using a BPTB autograft may be treated nonoperatively. PMID:23288745

  20. [Repair of a triceps tendon rupture using autogenous semi-tendinous and gracilis tendons. A case report and retrospective chart review].

    PubMed

    Dos Remedios, C; Brosset, T; Chantelot, C; Fontaine, C

    2007-06-01

    The authors report the rare case of an athlete having a complete rupture of the distal triceps tendon associated with severe chronic degenerative pathology of the triceps tendon induced by forced weight-lifting exercises and repetitive corticosteroid injections. Reconstruction of the ruptured triceps was possible using autogenous semi-tendinous and gracilis tendons. The good functional outcome obtained with this technique and the analysis of the retrospective chart review suggest that when direct reattachment is impossible (tendon retraction or loss of tendon in post-traumatic or degenerative injury) or not sufficient (weakness after total elbow arthroplasty surgery), the use of an autogenous semi-tendinous and gracilis tendons permits a good functional outcome. PMID:17616417

  1. Missed Medial Malleolar Fracture Associated With Achilles Tendon Rupture: A Case Report and Literature Review.

    PubMed

    Nakajima, Koji; Taketomi, Shuji; Inui, Hiroshi; Nakamura, Kensuke; Sanada, Takaki; Tanaka, Sakae

    2016-01-01

    A 45-year-old man sustained an Achilles tendon rupture while playing futsal. A concomitant medial malleolar fracture was not diagnosed until the patient underwent an operation for Achilles tendon repair. A routine postoperative radiograph showed a minimally displaced medial malleolar fracture. Conservative treatment was chosen for the fracture. The function of the Achilles tendon recovered well, and the fracture was united. A medial malleolar fracture can be missed when an Achilles tendon rupture occurs simultaneously. Thus, surgeons should consider the possibility of medial malleolar fracture associated with an Achilles tendon rupture. PMID:25441273

  2. Experimental flexor tendon healing without adhesion formation--a new concept of tendon nutrition and intrinsic healing mechanisms. A preliminary report.

    PubMed

    Lundborg, G

    1976-10-01

    An experimental model is presented enabling an analysis of the healing process of completely cut and re-sutured free segments of rabbit flexor tendons, kept avascular in a synovial milieu and completely isolated from adhesion formation. Under these conditions the cut tendons heal within a few weeks. It can be shown that this healing process is a result of intrinsic tendon cell activity only. PMID:976821

  3. 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 at baseline were risk factors for developing symptoms of jumper's knee. Also, among healthy athletes, we observed a 7-11% increase in quadriceps tendon thickness, while there was no increase in patellar tendon thickness. PMID:24612006

  4. Engineered tendon with decellularized xenotendon slices and bone marrow stromal cells: an in vivo animal study

    PubMed Central

    Omae, Hiromichi; Sun, Yu Long; An, Kai-Nan; Amadio, Peter C.; Zhao, Chunfeng

    2013-01-01

    The purpose of this study was to investigate an engineered composite of multilayer acellular tendon slices seeded with bone marrow stromal cells (BMSCs) as a possible solution for tendon reconstruction. BMSCs were harvested from 15 rabbits and infraspinatus tendons were harvested from 17 dogs. The decellularized tendons were sectioned in longitudinal slices with a thickness of 50 ?m. The BMSCs were seeded on the slices and then the slices were bundled into one composite. The composite was implanted into a rabbit patellar tendon defect. Tendon slices without BMSCs were implanted into the contralateral patellar tendon as a control. The composites were evaluated by histology and qRT–PCR. The viability of BMSCs was assessed using a fluorescent marker. Histology showed viable cells between the collagen fibres on the cell-seeded side. Analysis by qRT–PCR showed higher tenomodulin, collagen type III, MMP3 and MMP13 expressions and lower collagen type I expression in the cell-seeded composite than in the tendon slices without BMSCs. We conclude that BMSCs can survive in a multilayer composite, express a tendon phenotype and enhance the metabolism of tendon in vivo. This in vivo study suggests a potential utility of this composite in tendon reconstruction. PMID:21449044

  5. Histopathological and biomechanical evaluation of tenocyte seeded allografts on rat Achilles tendon regeneration.

    PubMed

    Güngörmü?, Cans?n; Kolankaya, Dürdane; Aydin, Erkin

    2015-05-01

    Tendon injuries in humans as well as in animals' veterinary medicine are problematic because tendon has poor regenerative capacity and complete regeneration of the ruptured tendon is never achieved. In the last decade there has been an increasing need of treatment methods with different approaches. The aim of the current study was to improve the regeneration process of rat Achilles tendon with tenocyte seeded decellularized tendon matrices. For this purpose, Achilles tendons were harvested, decellularized and seeded as a mixture of three consecutive passages of tenocytes at a density of 1 × 10(6) cells/ml. Specifically, cells with different passage numbers were compared with respect to growth characteristics, cellular senescence and collagen/tenocyte marker production before seeding process. The viability of reseeded tendon constructs was followed postoperatively up to 6 months in rat Achilles tendon by histopathological and biomechanical analysis. Our results suggests that tenocyte seeded decellularized tendon matrix can significantly improve the histological and biomechanical properties of tendon repair tissue without causing adverse immune reactions. To the best of our knowledge, this is the first long-term study in the literature which was accomplished to prove the use of decellularized matrix in a clinically relevant model of rat Achilles tendon and the method suggested herein might have important implications for translation into the clinic. PMID:25771002

  6. 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.

  7. 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

  8. Presence of a long accessory flexor tendon of the toes in surgical treatment for tendinopathy of the insertion of the calcaneal tendon: case report☆

    PubMed Central

    Gomes Júnior, Nelson Pelozo; Andreoli, Carlos Vicente; Pochini, Alberto de Castro; Raduan, Fernando Cipolini; Ejnisman, Benno; Cohen, Moisés

    2015-01-01

    The presence of accessory tendons in the foot and ankle needs to be recognized, given that depending on their location, they may cause disorders relating either to pain processes or to handling of the surgical findings. We describe the presence of an accessory flexor tendon of the toes, seen in surgical exposure for transferring the long flexor tendon of the hallux to the calcaneus, due to the presence of a disorder of tendinopathy of the insertion of the calcaneal tendon in association with Haglund's syndrome.

  9. Use of a Hunter Rod for Staged Reconstruction of Peroneal Tendons.

    PubMed

    Raikin, Steven M; Schick, Faith A; Karanjia, Homyar N

    2016-01-01

    Peroneal tendon pathology is a commonly reported cause of lateral ankle pain. The causes include cavovarus foot type, overuse, chronic tendinosis, peroneal subluxation or dislocation, acute traumatic split tears, and traumatic rupture. The purpose of the present report is to describe an alternative approach for surgical reconstruction of the peroneal tendons in patients when repair might no longer be effective. The use of a Hunter rod was originally described by Hunter in 1971 for 2-stage reconstruction of tendons in the hand. We present a 2-stage surgical technique with the use of a Hunter rod as a temporary implant to stimulate generation of a healthy peroneal tendon sheath to host a flexor hallucis longus tendon transfer. This has proved to be a successful treatment option for patients with severe peroneal tendon damage and scarring along the peroneal tendon sheath. We offer a sample case to illustrate a patient with such indications. PMID:26282362

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

    PubMed Central

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

    2013-01-01

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

  11. Allograft anterior tibialis tendon with bioabsorbable interference screw fixation in anterior cruciate ligament reconstruction.

    PubMed

    Caborn, David N M; Selby, Jeffrey B

    2002-01-01

    For a variety of reasons, bone-patellar tendon-bone and Achilles tendon allografts have been used more commonly in anterior cruciate ligament reconstruction. Soft-tissue allografts used mainly are the semitendinosus, gracilis, and occasionally the quadriceps tendons. The anterior tibialis tendon is a thick, strong tendon that can be prepared with one doubling of the graft, has a large cross-sectional area, and has been shown to be stronger than semitendinosus, gracilis, patellar tendon, and native anterior cruciate ligament. Use of allograft shortens surgical time, eliminates graft harvest-site morbidity, and allows for a large supply of grafts for repeat or multiple ligament procedures. This graft can be fixed to the femoral and tibial bone tunnels with bioabsorbable interference screws for a hardware-free, completely endoscopic procedure. Two- to 4-year results of allograft procedures are comparable to autograft procedures, and there have been no early failures with this described technique using anterior tibialis tendon. PMID:11774151

  12. Allograft anterior tibialis tendon with bioabsorbable interference screw fixation in anterior cruciate ligament reconstruction.

    TOXLINE Toxicology Bibliographic Information

    Caborn DN; Selby JB

    2002-01-01

    For a variety of reasons, bone-patellar tendon-bone and Achilles tendon allografts have been used more commonly in anterior cruciate ligament reconstruction. Soft-tissue allografts used mainly are the semitendinosus, gracilis, and occasionally the quadriceps tendons. The anterior tibialis tendon is a thick, strong tendon that can be prepared with one doubling of the graft, has a large cross-sectional area, and has been shown to be stronger than semitendinosus, gracilis, patellar tendon, and native anterior cruciate ligament. Use of allograft shortens surgical time, eliminates graft harvest-site morbidity, and allows for a large supply of grafts for repeat or multiple ligament procedures. This graft can be fixed to the femoral and tibial bone tunnels with bioabsorbable interference screws for a hardware-free, completely endoscopic procedure. Two- to 4-year results of allograft procedures are comparable to autograft procedures, and there have been no early failures with this described technique using anterior tibialis tendon.

  13. How obesity modifies tendons (implications for athletic activities)

    PubMed Central

    Abate, Michele

    2014-01-01

    Summary Background: obesity is a well recognized risk factor for dysmetabolic and cardiovascular diseases, but can also be associated to musculo-skeletal disorders. Methods: a search of English-language articles was performed using the key search terms “obesity” or “body mass index” combined with “tendon”, or “tendinopathy”, indipendently. Results: several studies show that, in obese subjects, tendons frequently undergo to degeneration, which can progress to a symptomatic stage, with pain and functional impairment. The main histopathologic findings are a relative paucity of small collagen fibrils, expression of an impaired remodeling process, deposition of lipid droplets which can abut to tendolipomatosis, and a disorganized architecture in the tension regions. Both load-bearing and non load-bearing tendons can be affected. This suggests that systemic factors play an important pathogenetic role. Indeed, adipose tissue releases several bioactive peptides and hormones (chemerin, lipocalin, leptin and adiponectin), and cytokines responsible of a systemic state of chronic low grade inflammation. Conclusion: Physical activity is strongly recommended to stop the progression of weight gain or to bring an obese individual into the normal weight range. Therefore, leisure sport activity is useful in obese subjects, but caution is mandatory, because tendons with sub-clinical damage, when submitted to overload, can easily reach the symptomatic threshold. PMID:25489546

  14. Tuberculosis tenosynovitis of the extensor tendons of the wrist

    PubMed Central

    Mrabet, Dalila; Ouenniche, Kmar; Mizouni, Habiba; Ounaies, Mouna; Khémiri, Chékib; Sahli, Héla; Sellami, Slaheddine

    2011-01-01

    Mycobacterial tuberculous tenosynovitis of the extensor tendon sheath is an extremely rare manifestation of extrapulmonary tuberculosis. The diagnosis may be easily delayed because of its non-specific clinical signs. We report a new case of tuberculous tenosynovitis of the extensor without concomitant pulmonary tuberculosis or documented immunodeficiency. PMID:22679046

  15. Changes in the Achilles tendon reflexes following Skylab missions

    NASA Technical Reports Server (NTRS)

    Baker, J. T.; Nicogossian, A. E.; Hoffler, G. W.; Johnson, R. L.; Hordinsky, J. R.

    1977-01-01

    Postflight measurements of Achilles tendon reflex duration on Skylab crewmen indicate a state of disequilibrium between the flexor and extensor muscle groups with an initial decrease in reflex duration. As the muscles regain strength and mass there occurs an overcompensation reflected by increased reflex duration. Finally, when a normal neuromuscular state is reached the reflex duration returns to baseline value.

  16. 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. PMID:25116231

  17. The use of Zylon fibers in ULDB tendons

    NASA Astrophysics Data System (ADS)

    Seely, Loren; Zimmerman, Mike; McLaughlin, Joe

    2004-01-01

    Early in the development of the ultra long duration balloon (ULDB), Zylon was selected as the tendon material due to its favorable stress-strain properties. It is a next generation fiber whose strength and modulus are almost double those of the Kevlar fibers. In addition there are two versions of the Zylon, as spun (AS) and high modulus (HM). Data will be presented on why HM was chosen. Early in the development process, it was learned that this material exhibited an unusual sensitivity to degradation by ambient light. This is in addition to the expected sensitivity to UV (Ultraviolet) radiation. The fiber manufacturer reported all of these properties in their literature. Due to the operating environment of the ULDB it is necessary to protect the tendons from both visible and UV radiation. Methods to protect the tendons will be discussed. In addition, information on the long term exposure of the braided tendon over a thirty-two month period in a controlled manufacturing plant will be provided. Special testing methods will be noted.

  18. Graft site morbidity with autogenous semitendinosus and gracilis tendons.

    PubMed

    Yasuda, K; Tsujino, J; Ohkoshi, Y; Tanabe, Y; Kaneda, K

    1995-01-01

    To distinguish between morbidity caused by harvesting semitendinosus and gracilis tendons and morbidity associated with anterior cruciate ligament reconstruction surgery, we performed a prospective randomized study using 65 patients who underwent anterior cruciate ligament reconstruction using these tendons. The patients underwent either contralateral (N = 34) or ipsilateral (N = 31) graft harvest. For the nonoperated knees in the ipsilateral harvest group, isometric and isokinetic strength of the quadriceps and hamstring muscles increased to approximately 120% of the preoperative value at 12 months after surgery. Compared with these knees, the tendon harvest did not affect quadriceps muscle strength at all. However, harvest did decrease hamstring muscles strength for 9 months after surgery. The graft harvest in the knees with anterior cruciate ligament reconstruction also did not significantly affect quadriceps muscle strength, but it did significantly decrease hamstring muscles strength only at 1 month. Activity-related soreness at the donor site was rarely restricting and resolved by 3 months. This study demonstrated that the semitendinosus and gracilis tendon graft is a reasonable choice to minimize the donor site morbidity in ligament reconstruction using autografts. PMID:8600739

  19. ARTHROSCOPY FOR TREATMENT OF REFRACTORY CALCIFIC TENDONITIS OF THE SHOULDER

    PubMed Central

    Fernandes, Marcos Rassi; Fernandes, Rui José

    2015-01-01

    Objective: To evaluate the results from arthroscopic treatment in patients with calcific tendonitis of the shoulder. Methods: Between September 2001 and June 2006, 55 patients with calcific tendonitis of the shoulder that was resistant to conservative treatment were evaluated, with follow-up of 12 to 70 months. The mean age was 42 years, ranging from 30 to 64 years; 44 patients were female (80%). There were 37 right shoulders, and 63.63% of the cases were on the dominant side. Pain was the main symptom, and the mean time between onset of symptoms and arthroscopy was 38 months (range: five to 120 months). The tendon affected was the supraspinatus in 42 cases, the infraspinatus in 11 cases and an association between these in two cases. Acromioplasty was carried out in 12 patients (21.82%) and subacromial bursectomy was performed in all cases. Results: According to the UCLA criteria, 46 cases were excellent and six were good, making a total of 52 satisfactory results (94.54%). Conclusion: Arthroscopic treatment of calcific tendonitis of the shoulder appears to be an effective method, with high rates of satisfactory results. Associated acromioplasty is not necessary.

  20. Investigation to predict patellar tendon reflex using motion analysis technique.

    PubMed

    Tham, L K; Osman, N A Abu; Lim, K S; Pingguan-Murphy, B; Abas, W A B Wan; Zain, N Mohd

    2011-05-01

    The investigation of patellar tendon reflex involves development of a reflex hammer holder, kinematic data collection and analysis of patellar reflex responses using motion analysis techniques. The main aim of this research is to explore alternative means of assessing reflexes as a part of routine clinical diagnosis. The motion analysis system was applied to provide quantitative data which is a more objective measure of the patellar tendon reflex. Kinematic data was collected from 28 males and 22 females whilst subjected to a knee jerk test. Further analysis of kinematic data was performed to predict relationships which might affect the patellar tendon reflex. All subjects were seated on a high stool with their legs hanging freely within the capture volume of the motion analysis system. Knee jerk tests were applied to all subjects, on both sides of the leg, by eliciting hypo, hyper, and normal reflexes. An additional reinforcement technique called the Jendrassik manoeuvre was also performed under the same conditions to elicit a normal patellar tendon reflex. The comparison of reflex response between genders showed that female subjects generally had a greater response compared to males. However, the difference in reflex response between the left leg and the right leg was not significant. Tapping strength to elicit a hyper-reflex produced greater knee-jerk compared to the normal clinical tapping strength. All results were in agreement with clinical findings and results found by some early researchers. PMID:21146440

  1. Scleraxis is required for the development of a functional tendon enthesis.

    PubMed

    Killian, Megan L; Thomopoulos, Stavros

    2016-01-01

    The attachment of dissimilar materials is a major engineering challenge, yet this challenge is seemingly overcome in biology. This study aimed to determine how the transcription factor Scleraxis (Scx) influences the development and maturation of the tendon-to-bone attachment (enthesis). Mice with conditional knockout (cKO) for Scx (Scx(flx/-), Prx1Cre(+)) and wild-type [(WT) Scx(flx/+) or Scx(flx/flx)] littermates were killed at postnatal days 7-56 (P7-P56). Enthesis morphometry, histology, and collagen alignment were investigated throughout postnatal growth. Enthesis tensile mechanical properties were also assessed. Laser microdissection of distinct musculoskeletal tissues was performed at P7 for WT, cKO, and muscle-unloaded (botulinum toxin A treated) attachments for quantitative PCR. cKO mice were smaller, with altered bone shape and impaired enthesis morphology, morphometry, and organization. Structural alterations led to altered mechanical properties; cKO entheses demonstrated reduced strength and stiffness. In P7 attachments, cKO mice had reduced expression of transforming growth factor (TGF) superfamily genes in fibrocartilage compared with WT mice. In conclusion, deletion of Scx led to impairments in enthesis structure, which translated into impaired functional (i.e., mechanical) outcomes. These changes may be driven by transient signaling cues from mechanical loading and growth factors.-Killian, M. L., Thomopoulos, S. Scleraxis is required for the development of a functional tendon enthesis. PMID:26443819

  2. A finite dissipative theory of temporary interfibrillar bridges in the extracellular matrix of ligaments and tendons

    PubMed Central

    Ciarletta, P.; Ben Amar, M.

    2009-01-01

    The structural integrity and the biomechanical characteristics of ligaments and tendons result from the interactions between collagenous and non-collagenous proteins (e.g. proteoglycans, PGs) in the extracellular matrix. In this paper, a dissipative theory of temporary interfibrillar bridges in the anisotropic network of collagen type I, embedded in a ground substance, is derived. The glycosaminoglycan chains of decorin are assumed to mediate interactions between fibrils, behaving as viscous structures that transmit deformations outside the collagen molecules. This approach takes into account the dissipative effects of the unfolding preceding fibrillar elongation, together with the slippage of entire fibrils and the strain-rate-dependent damage evolution of the interfibrillar bridges. Thermodynamic consistency is used to derive the constitutive equations, and the transition state theory is applied to model the rearranging properties of the interfibrillar bridges. The constitutive theory is applied to reproduce the hysteretic spectrum of the tissues, demonstrating how PGs determine damage evolution, softening and non-recoverable strains in their cyclic mechanical response. The theoretical predictions are compared with the experimental response of ligaments and tendons from referenced studies. The relevance of the proposed model in mechanobiology research is discussed, together with several applications from medical practice to bioengineering science. PMID:19106068

  3. Age-related changes in mechanical properties of the Achilles tendon

    PubMed Central

    Waugh, C M; Blazevich, A J; Fath, F; Korff, T

    2012-01-01

    The stiffness of a tendon, which influences muscular force transfer to the skeleton and increases during childhood, is dependent on its material properties and dimensions, both of which are influenced by chronic loading. The aims of this study were to: (i) determine the independent contributions of body mass, force production capabilities and tendon dimensions to tendon stiffness during childhood; and (ii) descriptively document age-related changes in tendon mechanical properties and dimensions. Achilles tendon mechanical and material properties were determined in 52 children (5–12 years) and 19 adults. Tendon stiffness and Young's modulus (YM) were calculated as the slopes of the force–elongation and stress-strain curves, respectively. Relationships between stiffness vs. age, mass and force, and between YM vs. age, mass and stress were determined by means of polynomial fits and multiple regression analyses. Mass was found to be the best predictor of stiffness, whilst stress was best related to YM (< 75 and 51% explained variance, respectively). Combined, mass and force accounted for up to 78% of stiffness variation. Up to 61% of YM variability could be explained using a combination of mass, stress and age. These results demonstrate that age-related increases in tendon stiffness are largely attributable to increased tendon loading from weight-bearing tasks and increased plantarflexor force production, as well as tendon growth. Moreover, our results suggest that chronic increases in tendon loading during childhood result in microstructural changes which increase the tendon's YM. Regarding the second aim, peak stress increased from childhood to adulthood due to greater increases in strength than tendon cross-sectional area. Peak strain remained constant as a result of parallel increases in tendon length and peak elongation. The differences in Achilles tendon properties found between adults and children are likely to influence force production, and ultimately movement characteristics, which should be explicitly examined in future research. PMID:22150089

  4. Involvement of Na+/Ca2+ exchanger in migration and contraction of rat cultured tendon fibroblasts

    PubMed Central

    Sakamoto, Kazuho; Owada, Yuki; Shikama, Yayoi; Wada, Ikuo; Waguri, Satoshi; Iwamoto, Takahiro; Kimura, Junko

    2009-01-01

    In response to injury and inflammation of tendons, tendon fibroblasts are activated, migrate to the wound, and eventually induce contraction of the extracellular matrices to repair the tissue. Under such conditions, Ca2+ signalling is involved in motility and contractility of tendon fibroblasts. Using cultured tendon fibroblasts isolated from rat Achilles tendons, we investigated functional expression of Na+/Ca2+ exchangers (NCX). The fluorometric study showed that the intracellular Ca2+ concentration ([Ca2+]i) was increased by reducing extracellular Na+ concentration ([Na+]o) in tendon fibroblasts. Selective NCX inhibitors, KB-R7943 and SEA0400, both attenuated [Na+]o-dependent [Ca2+]i elevation and the resting [Ca2+]i in tendon fibroblasts. RT-PCR, Western blots and sequence analyses revealed that NCX1.3 and NCX1.7 were expressed in cultured tendon fibroblasts. NCX2 mRNA was undetected. NCX3 expression was negligibly low. Immunofluorescence microscopy indicated that NCX1 protein localized in the plasma membrane especially at the microspikes of tendon fibroblasts. In the wound-healing scratch assay, the cells migrated toward the space created by a scratch and almost completely filled the space within 48 h. This phenomenon was significantly suppressed by KB-R7943 and SEA0400. Furthermore, the NCX inhibitors abrogated the tendon fibroblast-mediated collagen-matrix contractions. Two types of siRNAs for NCX1 also suppressed the migration and contraction of tendon fibroblasts. We conclude that NCX is expressed and mediates Ca2+ influx in cultured tendon fibroblasts. Since the pharmacological inhibitors and siRNA for NCX1 suppressed motility and contractility of tendon fibroblasts, NCX may play an important role in the function of tendon fibroblasts in the wound healing. PMID:19770194

  5. The role of vasculature and angiogenesis for the pathogenesis of degenerative tendons disease.

    PubMed

    Pufe, T; Petersen, W J; Mentlein, R; Tillmann, B N

    2005-08-01

    More than 100 years ago Wilhelm Roux (1895) introduced the term "functional adaptation to anatomy and physiology". Compared with other organ systems the functional adaptation processes are best identifiable in the locomotor system, like for example in the two types of tendons: traction and gliding tendons. Traction tendons are tendons where the direction of pull is in line with the direction of the muscle (e.g. Achilles tendon). Gliding tendons (e.g. tibialis posterior tendon) change direction by turning around a bony or fibrous hypomochlion. In this region the tendon is subjected to intermittent compressive and shear forces and the extracellular matrix consists of avascular fibrocartilage. Avascularity is considered to be a key factor for the etiology of degenerative tendon disease. The repair capability after repetitive microtrauma is strongly compromised in avascular tissue of gliding tendons. Reduced vascularity is not a specific feature of gliding tendons; several studies have shown that the number and size of blood vessels are largely shortened in the waist of the Achilles tendon. However, histological biopsies from degenerated Achilles tendons and Doppler flow examinations revealed a high blood vessel density in patients with degenerative tendon disease. Angiogenesis is mediated by angiogenic factors and recent studies have shown that the vascular endothelial growth factor (VEGF) is highly expressed in degenerative Achilles tendons, whereas VEGF expression is nearly completely downregulated in healthy tendons. Several factors are able to upregulate VEGF expression in tenocytes: hypoxia, inflammatory cytokines and mechanical load. Since VEGF has the potential to stimulate the expression of matrix metalloproteinases and inhibit the expression of tissue inhibitors of matrix metalloproteinases tissue inhibitor of metalloproteinases (TIMP) in various cell types (e.g. endothelial cells, fibroblasts, chondrocytes), this cytokine might play a significant role for the pathogenetic processes during degenerative tendon disease. An animal experiment in the rabbit has shown that local injection of VEGF reduced the material properties of the Achilles tendon. These experimental findings are in accordance with clinical results that a locally administered (in the area with neovascularization) sclerosing drug (Polidocanol) has a beneficial effect on chronic mid-portion Achilles tendinosis. In conclusion, decreased and increased vascularity might be involved in the pathogenesis of degenerative Achilles tendon disease. PMID:15998338

  6. Functional Consequence of Distal Brachioradialis Tendon Release: A Biomechanical Study

    PubMed Central

    Tirrell, Timothy F.; Franko, Orrin I.; Bhola, Siddharth; Hentzen, Eric R.; Abrams, Reid A.; Lieber, Richard L.

    2013-01-01

    Purpose Open reduction and internal fixation of distal radius fractures often necessitates release of the brachioradialis from the radial styloid. However, this common procedure has the potential to decrease elbow flexion strength. To determine the potential morbidity associated with brachioradialis release, we measured the change in elbow torque as a function of incremental release of the brachioradialis insertion footprint. Methods In 5 upper extremity cadaveric specimens, the brachioradialis tendon was systematically released from the radius, and the resultant effect on brachioradialis elbow flexion torque was measured. Release distance was defined as the distance between the release point and the tip of the radial styloid. Results Brachioradialis elbow flexion torque dropped to 95%, 90% and 86% of its original value at release distances of 27mm, 46mm, and 52mm, respectively. Importantly, brachioradialis torque remained above 80% of its original value at release distances up to 7 centimeters. Conclusions Our data demonstrate that release of the brachioradialis tendon from its insertion has minor effects on its ability to transmit force to the distal radius. Clinical Relevance These data may imply that release of the distal brachioradialis tendon during distal radius open reduction internal fixation can be performed without meaningful functional consequences to elbow flexion torque. Even at large release distances, overall elbow flexion torque loss after brachioradialis release would be expected to be less than 5% due to the much larger contributions of the biceps and brachialis. Use of the brachioradialis as a tendon transfer donor should not be limited by concerns of elbow flexion loss, and the tendon could be considered as an autograft donor. PMID:23528425

  7. Genetic Response of Rat Supraspinatus Tendon and Muscle to Exercise

    PubMed Central

    Rooney, Sarah Ilkhanipour; Tobias, John W.; Bhatt, Pankti R.; Kuntz, Andrew F.; Soslowsky, Louis J.

    2015-01-01

    Inflammation is a complex, biologic event that aims to protect and repair tissue. Previous studies suggest that inflammation is critical to induce a healing response following acute injury; however, whether similar inflammatory responses occur as a result of beneficial, non-injurious loading is unknown. The objective of this study was to screen for alterations in a subset of inflammatory and extracellular matrix genes to identify the responses of rat supraspinatus tendon and muscle to a known, non-injurious loading condition. We sought to define how a subset of genes representative of specific inflammation and matrix turnover pathways is altered in supraspinatus tendon and muscle 1) acutely following a single loading bout and 2) chronically following repeated loading bouts. In this study, Sprague-Dawley rats in the acute group ran a single bout of non-injurious exercise on a flat treadmill (10 m/min, 1 hour) and were sacrificed 12 or 24 hours after. Rats in the chronic group ran 5 days/wk for 1 or 8 weeks. A control group maintained normal cage activity. Supraspinatus muscle and tendon were harvested for RNA extractions, and a custom Panomics QuantiGene 2.0 multiplex assay was used to detect 48 target and 3 housekeeping genes. Muscle/tendon and acute/chronic groups had distinct gene expression. Components of the arachidonic acid cascade and matrix metalloproteinases and their inhibitors were altered with acute and chronic exercise. Collagen expression increased. Using a previously validated model of non-injurious exercise, we have shown that supraspinatus tendon and muscle respond to acute and chronic exercise by regulating inflammatory- and matrix turnover-related genes, suggesting that these pathways are involved in the beneficial adaptations to exercise. PMID:26447778

  8. Accelerated corrosion testing, evaluation and durability design of bonded post-tensioned concrete tendons

    NASA Astrophysics Data System (ADS)

    Salas Pereira, Ruben Mario

    2003-06-01

    In the last few years, the effectiveness of cement grout in galvanized or polyethylene ducts, the most widely used corrosion protection system for multistrand bonded post-tensioned concrete tendons, has been under debate, due to significant tendon corrosion damage, several reported failures of individual tendons as well as a few collapses of non-typical structures. While experience in the USA has been generally good, some foreign experience has been less than satisfactory. This dissertation is part of a comprehensive research program started in 1993, which has the objectives to examine the use of post-tensioning in bridge substructures, identify durability concerns and existing technology, develop and carry out an experimental testing program, and conclude with durability design guidelines. Three experimental programs were developed: A long term macrocell corrosion test series, to investigate corrosion protection for internal tendons in precast segmental construction; a long term beam corrosion test series, to examine the effects of post-tensioning on corrosion protection as affected by crack width; and, a long term column corrosion test series, to examine corrosion protection in vertical elements. Preliminary design guidelines were developed previously in the overall study by the initial researchers, after an extensive literature review. This dissertation scope includes continuation of exposure testing of the macrocell, beam and column specimens, performing comprehensive autopsies of selected specimens and updating the durability design guidelines based on the exposure testing and autopsy results. After autopsies were performed, overall findings indicate negative durability effects due to the use of mixed reinforcement, small concrete covers, galvanized steel ducts, and industry standard or heat-shrink galvanized duct splices. The width of cracks was shown to have a direct negative effect on specimen performance. Grout voids were found to be detrimental to the durability of both galvanized ducts and strand. Relying on epoxy and galvanized bar coatings was also found inappropriate because of local attack. On the other hand, very positive effects were found with the use of high performance concrete, high post-tensioning levels, plastic ducts, and sound epoxy filling at the joints.

  9. Biomechanical properties and histology of db/db diabetic mouse Achilles tendon.

    PubMed

    Boivin, Gregory P; Elenes, Egleide Y; Schultze, Andrew K; Chodavarapu, Harshita; Hunter, Shawn A; Elased, Khalid M

    2014-07-01

    Foot ulcers are a severe complication of diabetic patients resulting from nerve and tendon pathologic alterations. In diabetic patients the tendons are thicker, shorter and have increased stiffness. We examined C57BL/KsJ (BKS.Cg-Dock7(m) +/+ Lepr (db) /J) (db/db) mice tendons to determine whether they are an animal model for human diabetic tendon changes. We hypothesized that the Achilles tendons of db/db diabetic mice would be thicker, stiffer, fail at lower loads and stresses, and have degenerative changes compared to control mice. Biomechanical and histologic analyses of the Achilles tendons of 16 week old db/db and control male mice were performed. There was a significant increase in tendon diameter and significant decreases in maximum load, tensile stress, stiffness and elastic modulus in tendons from diabetic mice compared to controls. Mild degenerative and neutrophil infiltration was observed near the tendon insertions on the calcaneous in 25% of db/db mice. In summary, hyper-glycemia and obesity lead to severe changes in db/db mice will be a useful model to examine mechanisms for tendon alterations. PMID:25489543

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

    PubMed Central

    2014-01-01

    Background Common peroneal nerve palsy leading to foot drop is difficult to manage and has historically been treated with extended bracing with expectant waiting for return of nerve function. Peroneal nerve exploration has traditionally been avoided except in cases of known traumatic or iatrogenic injury, with tendon transfers being performed in a delayed fashion after exhausting conservative treatment. We present a new strategy for management of foot drop with nerve exploration and concomitant tendon transfer. Method We retrospectively reviewed a series of 12 patients with peroneal nerve palsies that were treated with tendon transfer from 2005 to 2011. Of these patients, seven were treated with simultaneous peroneal nerve exploration and repair at the time of tendon transfer. Results Patients with both nerve repair and tendon transfer had superior functional results with active dorsiflexion in all patients, compared to dorsiflexion in 40% of patients treated with tendon transfers alone. Additionally, 57% of patients treated with nerve repair and tendon transfer were able to achieve enough function to return to running, compared to 20% in patients with tendon transfer alone. No patient had full return of native motor function resulting in excessive dorsiflexion strength. Conclusion The results of our limited case series for this rare condition indicate that simultaneous nerve repair and tendon transfer showed no detrimental results and may provide improved function over tendon transfer alone. PMID:25099247

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

    PubMed Central

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

    2013-01-01

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

  12. The cellular biology of flexor tendon adhesion formation: an old problem in a new paradigm.

    PubMed

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

    2009-11-01

    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

  13. Biomechanical properties and histology of db/db diabetic mouse Achilles tendon

    PubMed Central

    Boivin, Gregory P.; Elenes, Egleide Y.; Schultze, Andrew K.; Chodavarapu, Harshita; Hunter, Shawn A.; Elased, Khalid M.

    2014-01-01

    Summary Foot ulcers are a severe complication of diabetic patients resulting from nerve and tendon pathologic alterations. In diabetic patients the tendons are thicker, shorter and have increased stiffness. We examined C57BL/KsJ (BKS.Cg-Dock7m +/+ Leprdb/J) (db/db) mice tendons to determine whether they are an animal model for human diabetic tendon changes. We hypothesized that the Achilles tendons of db/db diabetic mice would be thicker, stiffer, fail at lower loads and stresses, and have degenerative changes compared to control mice. Biomechanical and histologic analyses of the Achilles tendons of 16 week old db/db and control male mice were performed. There was a significant increase in tendon diameter and significant decreases in maximum load, tensile stress, stiffness and elastic modulus in tendons from diabetic mice compared to controls. Mild degenerative and neutrophil infiltration was observed near the tendon insertions on the calcaneous in 25% of db/db mice. In summary, hyper-glycemia and obesity lead to severe changes in db/db mice will be a useful model to examine mechanisms for tendon alterations. PMID:25489543

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

    PubMed Central

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

    2016-01-01

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

  15. Wounds of the distal limb complicated by involvement of deep structures.

    PubMed

    Jann, Henry; Pasquini, Chris

    2005-04-01

    The authors describe the clinically relevant structures of the distal limb and the current diagnostic and treatment modalities. Specific problems include tendon laceration, septic tenosynovitis, and sep-tic arthritis of the distal joints. A detailed description of tendon repair, tendon sheath lavage, and postoperative convalescent methodology is provided. This article makes available to the reader information necessary to appropriately diagnose and treat wounds of the distal equine limb involving deep structures. Information on the overall prognosis is also provided. PMID:15691605

  16. Fetal Development of the Human Obturator Internus Muscle With Special Reference to the Tendon and Pulley.

    PubMed

    Naito, Michiko; Suzuki, Ryoji; Abe, Hiroshi; Rodriguez-Vazquez, Jose Francisco; Murakami, Gen; Aizawa, Shin

    2015-07-01

    To examine the development of the tendon pulley of the obturator internus muscle (OI), we observed paraffin sections of 26 human embryos and fetuses (?6-15 weeks of gestation). The OI was characterized by early maturation of the proximal tendon in contrast to the delayed development of the distal tendon. At 6 weeks, the ischium corresponded to a simple round mass similar to the tuberosity in adults. At 8 weeks, before development of the definite lesser notch of the ischium, initial muscle fibers of the OI, running along the antero-posterior axis, converged onto a thick and tight but short tendon running along the left-right axis. Thus, at the beginning of development, the OI muscle belly and tendon met almost at a right angle. At 10 weeks, the OI tendon extended inferiorly along the sciatic nerve, but the distal part remained thin and loose and it was embedded in the gluteus medius tendon. At 15 weeks, in association with the gemellus muscles, the distal OI tendon was established. The mechanically strong sciatic nerve was first likely to catch the OI muscle fibers to provide a temporary insertion. Next, the ischium developing upward seemed to push the tendon to make the turn more acute along the cartilaginous ridge. Finally, the gemellus muscle appeared to provide inferior traction to the OI tendon for separation from the gluteus medius to create the final, independent insertion. Without such guidance, the piriformis tendon first attached to the OI tendon and then merged with the gluteus medius tendon. PMID:25683268

  17. Equine Induced Pluripotent Stem Cells have a Reduced Tendon Differentiation Capacity Compared to Embryonic Stem Cells.

    PubMed

    Bavin, Emma P; Smith, Olivia; Baird, Arabella E G; Smith, Lawrence C; Guest, Deborah J

    2015-01-01

    Tendon injuries occur commonly in horses and their repair through scar tissue formation predisposes horses to a high rate of re-injury. Pluripotent stem cells may provide a cell replacement therapy to improve tendon tissue regeneration and lower the frequency of re-injury. We have previously demonstrated that equine embryonic stem cells (ESCs) differentiate into the tendon cell lineage upon injection into the damaged horse tendon and can differentiate into functional tendon cells in vitro to generate artificial tendons. Induced pluripotent stem cells (iPSCs) have now been derived from horses but, to date, there are no reports on their ability to differentiate into tendon cells. As iPSCs can be produced from adult cell types, they provide a more accessible source of cells than ESCs, which require the use of horse embryos. The aim of this study was to compare tendon differentiation by ESCs and iPSCs produced through two independent methods. In two-dimensional differentiation assays, the iPSCs expressed tendon-associated genes and proteins, which were enhanced by the presence of transforming growth factor-?3. However, in three-dimensional (3D) differentiation assays, the iPSCs failed to differentiate into functional tendon cells and generate artificial tendons. These results demonstrate the utility of the 3D in vitro tendon assay for measuring tendon differentiation and the need for more detailed studies to be performed on equine iPSCs to identify and understand their epigenetic differences from pluripotent ESCs prior to their clinical application. PMID:26664982

  18. Functionally distinct tendon fascicles exhibit different creep and stress relaxation behaviour

    PubMed Central

    Legerlotz, Kirsten; Demirci, Taylan; Klemt, Christian; Riley, Graham P; Screen, Hazel RC

    2014-01-01

    Most overuse tendinopathies are thought to be associated with repeated microstrain below the failure threshold, analogous to the fatigue failure that affects materials placed under repetitive loading. Investigating the progression of fatigue damage within tendons is therefore of critical importance. There are obvious challenges associated with the sourcing of human tendon samples for in vitro analysis so animal models are regularly adopted. However, data indicates that fatigue life varies significantly between tendons of different species and with different stresses in life. Positional tendons such as rat tail tendon or the bovine digital extensor are commonly applied in in vitro studies of tendon overuse, but there is no evidence to suggest their behaviour is indicative of the types of human tendon particularly prone to overuse injuries. In this study, the fatigue response of the largely positional digital extensor and the more energy storing deep digital flexor tendon of the bovine hoof were compared to the semitendinosus tendon of the human hamstring. Fascicles from each tendon type were subjected to either stress or strain controlled fatigue loading (cyclic creep or cyclic stress relaxation respectively). Gross fascicle mechanics were monitored after cyclic stress relaxation and the mean number of cycles to failure investigated with creep loading. Bovine extensor fascicles demonstrated the poorest fatigue response, while the energy storing human semitendinosus was the most fatigue resistant. Despite the superior fatigue response of the energy storing tendons, confocal imaging suggested a similar degree of damage in all three tendon types; it appears the more energy storing tendons are better able to withstand damage without detriment to mechanics. PMID:24285289

  19. Equine Induced Pluripotent Stem Cells have a Reduced Tendon Differentiation Capacity Compared to Embryonic Stem Cells

    PubMed Central

    Bavin, Emma P.; Smith, Olivia; Baird, Arabella E. G.; Smith, Lawrence C.; Guest, Deborah J.

    2015-01-01

    Tendon injuries occur commonly in horses and their repair through scar tissue formation predisposes horses to a high rate of re-injury. Pluripotent stem cells may provide a cell replacement therapy to improve tendon tissue regeneration and lower the frequency of re-injury. We have previously demonstrated that equine embryonic stem cells (ESCs) differentiate into the tendon cell lineage upon injection into the damaged horse tendon and can differentiate into functional tendon cells in vitro to generate artificial tendons. Induced pluripotent stem cells (iPSCs) have now been derived from horses but, to date, there are no reports on their ability to differentiate into tendon cells. As iPSCs can be produced from adult cell types, they provide a more accessible source of cells than ESCs, which require the use of horse embryos. The aim of this study was to compare tendon differentiation by ESCs and iPSCs produced through two independent methods. In two-dimensional differentiation assays, the iPSCs expressed tendon-associated genes and proteins, which were enhanced by the presence of transforming growth factor-β3. However, in three-dimensional (3D) differentiation assays, the iPSCs failed to differentiate into functional tendon cells and generate artificial tendons. These results demonstrate the utility of the 3D in vitro tendon assay for measuring tendon differentiation and the need for more detailed studies to be performed on equine iPSCs to identify and understand their epigenetic differences from pluripotent ESCs prior to their clinical application. PMID:26664982

  20. Oriented hydroxyapatite in turkey tendon mineralized via the polymer-induced liquid-precursor (PILP) process

    SciTech Connect

    Jee, S.S.; DiMasi, E.; Kasinath, R.K.; Kim, Y.Y.; Gower, L.

    2010-12-03

    Bone is a hierarchically structured composite which imparts it with unique mechanical properties and bioresorptive potential. These properties are primarily influenced by the underlying nanostructure of bone, which consists of nanocrystals of hydroxyapatite embedded and uniaxially aligned within collagen fibrils. There is also a small fraction of non-collagenous proteins in bone, and these are thought to play an important role in bone's formation. In our in vitro model system of bone formation, polyanionic peptides are used to mimic the role of the non-collagenous proteins. In our prior studies, we have shown that intrafibrillar mineralization can be achieved in synthetic reconstituted collagen sponges using a polymer-induced liquid-precursor (PILP) mineralization process. This led to a nanostructured arrangement of hydroxyapatite crystals within the individual fibrils which closely mimics that of bone. This report demonstrates that biogenic collagen scaffolds obtained from turkey tendon, which consist of densely packed and oriented collagen fibrils, can also be mineralized by the PILP process. Synchrotron X-ray diffraction studies show that the mineralization process leads to a high degree of crystallographic orientation at the macroscale, thus emulating that found in the biological system of naturally mineralizing turkey tendon.

  1. An Investigation of the Bound Water in Tendon by Dielectric Measurement

    PubMed Central

    Lim, J. J.; Shamos, M. H.

    1971-01-01

    The dielectric constant of natural tendon in the frequency range of 200 Hz to 100 kHz has been determined as a function of temperature (300-450°K) for water concentrations ranging from about 6 to 16% by weight. The results compare well with the approach taken by Haggis and his coworkers. Based on the assumption that at low concentration of water the probability of water-water bonding is small and hence may be disregarded, a structure for water in the collagen matrix is proposed in which the water is either bonded in one of four possible states to the polar groups of the polypeptide chains, or is unbound. In determining the distribution of the water among these states an approach similar to that of Haggis and his co-workers, in conjunction with the order-disorder theory of Bragg and Williams, is used. The number of water molecules per unit volume is then determined experimentally by relating it to weight loss as a function of temperature, as determined by thermogravimetric analysis. The dispersion which is normally found in dipolar substances has not been found for tendon. A maximum in the value of the dielectric constant is observed to occur between 25 and 80°C, the temperature depending upon the heating rate. PMID:5116581

  2. Effect of highly purified capsaicin on articular cartilage and rotator cuff tendon healing: An in vivo rabbit study.

    PubMed

    Friel, Nicole A; McNickle, Allison G; DeFranco, Michael J; Wang, FanChia; Shewman, Elizabeth F; Verma, Nikhil N; Cole, Brian J; Bach, Bernard R; Chubinskaya, Susan; Kramer, Susan M; Wang, Vincent M

    2015-12-01

    Highly purified capsaicin has emerged as a promising injectable compound capable of providing sustained pain relief following a single localized treatment during orthopedic surgical procedures. To further assess its reliability for clinical use, the potential effect of highly purified capsaicin on articular cartilage metabolism as well as tendon structure and function warrants clarification. In the current study, rabbits received unilateral supraspinatus transection and repair with a single 1?ml injection of capsaicin (R+C), PEG-only placebo (R+P), or saline (R+S) into the glenohumeral joint (GHJ). An additional group received 1?ml capsaicin onto an intact rotator cuff (I+C). At 18 weeks post-op, cartilage proteoglycan (PG) synthesis and content as well as cell viability were similar (p>0.05) across treatment groups. Biomechanical testing revealed no differences (p>0.05) among tendon repair treatment groups. Similarly, histologic features of both cartilage and repaired tendons showed minimal differences across groups. Hence, in this rabbit model, a single injection of highly purified capsaicin into the GHJ does not induce a deleterious response with regard to cartilage matrix metabolism and cell viability, or rotator cuff healing. These data provide further evidence supporting the use of injectable, highly purified capsaicin as a safe alternative for management of postoperative pain following GHJ surgery. PMID:26135547

  3. Botulinum Neurotoxin A Injections Influence Stretching of the Gastrocnemius Muscle-Tendon Unit in an Animal Model

    PubMed Central

    Haubruck, Patrick; Mannava, Sandeep; Plate, Johannes F.; Callahan, Michael F.; Wiggins, Walter F.; Schmidmaier, Gerhard; Tuohy, Christopher J.; Saul, Katherine R.; Smith, Thomas L.

    2012-01-01

    Botulinum Neurotoxin A (BoNT-A) injections have been used for the treatment of muscle contractures and spasticity. This study assessed the influence of (BoNT-A) injections on passive biomechanical properties of the muscle-tendon unit. Mousegastrocnemius muscle (GC) was injected with BoNT-A (n = 18) or normal saline (n = 18) and passive, non-destructive, in vivo load relaxation experimentation was performed to examine how the muscle-tendon unit behaves after chemical denervation with BoNT-A. Injection of BoNT-A impaire