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1

Tendon structure, disease, and imaging  

PubMed Central

Summary Tendon imaging plays a critical role in evaluating tendon diseases and injuries including mechanical, degenerative, and overuse disease, inflammatory enthesitis, as well as partial and full thickness tears. Ultrasound and magnetic resonance imaging (MRI), each with unique benefits and limitations, are commonly utilized to assist in diagnosing these diseases and conditions. This review delineates important structural properties of tendon and biochemical changes occurring in tendon pathology. This review also examines commonly injured tendons including tendons of the elbow, tendons of the rotator cuff of the shoulder, hip abductor tendons, patellar tendons, and the Achilles tendon to help clinicians better recognize tendon disease. Finally, this paper introduces several emerging imaging techniques including T2 mapping, ultra-short echo time MRI, and sonoelastography as ways in which tendon imaging and evaluation may be improved. PMID:24932450

Weinreb, Jeffrey H.; Sheth, Chirag; Apostolakos, John; McCarthy, Mary-Beth; Barden, Benjamin; Cote, Mark P.; Mazzocca, Augustus D.

2014-01-01

2

Effect of estrogen on tendon collagen synthesis, tendon structural characteristics, and biomechanical properties in postmenopausal women.  

PubMed

The knowledge about the effect of estradiol on tendon connective tissue is limited. Therefore, we studied the influence of estradiol on tendon synthesis, structure, and biomechanical properties in postmenopausal women. Nonusers (control, n = 10) or habitual users of oral estradiol replacement therapy (ERT, n = 10) were studied at rest and in response to one-legged resistance exercise. Synthesis of tendon collagen was determined by stable isotope incorporation [fractional synthesis rate (FSR)] and microdialysis technique (NH(2)-terminal propeptide of type I collagen synthesis). Tendon area and fibril characteristics were determined by MRI and transmission electron microscopy, whereas tendon biomechanical properties were measured during isometric maximal voluntary contraction by ultrasound recording. Tendon FSR was markedly higher in ERT users (P < 0.001), whereas no group difference was seen in tendon NH(2)-terminal propeptide of type I collagen synthesis (P = 0.32). In ERT users, positive correlations between serum estradiol (s-estradiol) and tendon synthesis were observed, whereas change in tendon synthesis from rest to exercise was negatively correlated to s-estradiol. Tendon area, fibril density, fibril volume fraction, and fibril mean area did not differ between groups. However, the percentage of medium-sized fibrils was higher in ERT users (P < 0.05), whereas the percentage of large fibrils tended to be greater in control (P = 0.10). A lower Young's modulus (GPa/%) was found in ERT users (P < 0.05). In conclusion, estradiol administration was associated with higher tendon FSR and a higher relative number of smaller fibrils. Whereas this indicates stimulated collagen turnover in the resting state, collagen responses to exercise were negatively associated with s-estradiol. These results indicate a pivotal role for estradiol in maintaining homeostasis of female connective tissue. PMID:18927264

Hansen, Mette; Kongsgaard, Mads; Holm, Lars; Skovgaard, Dorthe; Magnusson, S Peter; Qvortrup, Klaus; Larsen, Jytte O; Aagaard, Per; Dahl, Morten; Serup, Annette; Frystyk, Jan; Flyvbjerg, Allan; Langberg, Henning; Kjaer, Michael

2009-04-01

3

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Inservice Inspection of Prestressed Concrete Containment Structures With Grouted Tendons...Inservice Inspection of Prestressed Concrete Containment Structures with Grouted Tendons...surveillance program for prestressed concrete containment structures with grouted...

2012-11-19

4

Aspects of mineral structure in normally calcifying avian tendon.  

PubMed

Structural characteristics of normally calcifying leg tendons of the domestic turkey Meleagris gallopavo have been observed for the first time by tapping mode atomic force microscopy (TMAFM), and phase as well as corresponding topographic images were acquired to gain insight into the features of mineralizing collagen fibrils and fibers. Analysis of different regions of the tendon has yielded new information concerning the structural interrelationships in vivo between collagen fibrils and fibers and mineral crystals appearing in the form of plates and plate aggregates. TMAFM images show numerous mineralized collagen structures exhibiting characteristic periodicity (54-70 nm), organized with their respective long axes parallel to each other. In some instances, mineral plates (30-40 nm thick) are found interspersed between and in intimate contact with the mineralized collagen. The edges of such plates lie parallel to the neighboring collagen. Many of these plates appear to be aligned to form larger aggregates (475-600 nm long x 75-90 nm thick) that also retain collagen periodicity along their exposed edges. Intrinsic structural properties of the mineralizing avian tendon have not previously been described on the scale reported in this study. These data provide the first visual evidence supporting the concept that larger plates form from parallel association of smaller ones, and the data fill a gap in knowledge between macromolecular- and anatomic-scale studies of the mineralization of avian tendon and connective tissues in general. The observed organization of mineralized collagen, plates, and plate aggregates maintaining a consistently parallel nature demonstrates the means by which increasing structural complexity may be achieved in a calcified tissue over greater levels of hierarchical order. PMID:11722171

Siperko, L M; Landis, W J

2001-09-01

5

Structure-Function Relationships of Postnatal Tendon Development: A Parallel to Healing  

PubMed Central

This review highlights recent research on structure-function relationships in tendon and comments on the parallels between development and healing. The processes of tendon development and collagen fibrillogenesis are reviewed, but due to the abundance of information in this field, this work focuses primarily on characterizing the mechanical behavior of mature and developing tendon, and how the latter parallels healing tendon. The role that extracellular matrix components, mainly collagen, proteoglycans, and collagen cross-links, play in determining the mechanical behavior of tendon will be examined in this review. Specifically, collagen fiber re-alignment and collagen fibril uncrimping relate mechanical behavior to structural alterations during development and during healing. Finally, attention is paid to a number of recent efforts to augment injured tendon and how future efforts could focus on recreating the important structure-function relationships reviewed here. PMID:23357642

Connizzo, Brianne K.; Yannascoli, Sarah M.; Soslowsky, Louis J.

2013-01-01

6

Tendon control deployment of tensegrity structures  

Microsoft Academic Search

In this paper we consider the problem of deployment of tensegrity structures. Our idea is to make use of a certain set of equilibria to which the undeployed and deployed configurations belong. In the state space this set is represented by a connected equilibrium manifold and can be completely characterized analytically. The deployment is conducted such that the deployment trajectory

Cornel Sultan; Robert E. Skelton

1998-01-01

7

Tendon control deployment of tensegrity structures  

NASA Astrophysics Data System (ADS)

In this paper we consider the problem of deployment of tensegrity structures. Our idea is to make use of a certain set of equilibria to which the undeployed and deployed configurations belong. In the state space this set is represented by a connected equilibrium manifold and can be completely characterized analytically. The deployment is conducted such that the deployment trajectory is close to the equilibrium manifold and the deployment time is minimized.

Sultan, Cornel; Skelton, Robert T.

1998-07-01

8

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

PubMed

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 uninjured 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 (R(2)=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

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

2014-06-27

9

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

PubMed

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

Tardioli, Alex; Malliaras, Peter; Maffulli, Nicola

2012-09-01

10

Effect of acute tensile loading on gender-specific tendon structural and mechanical properties.  

PubMed

Stretching is commonly used prior to exercise, as it is thought to reduce the risk of injury, and it is also used in the preconditioning of tendon grafts. As tendon properties have been shown to be different between genders, it is proposed that stretching will differentially affect the structure. Here we examine the effect of acute stretch on the mechanical properties of both male and female medial gastrocnemius tendon. Female [20 years +/- 1 (SEM), n = 17] and male (22 years +/- 1, n = 18) subjects underwent a 5-min passive dorsiflexion stretch. Prior to and post stretch medial gastrocnemius tendon stiffness (K), length (l) and cross-sectional area (csa) were measured using ultrasonography and dynamometry. Stiffness and Young's modulus (epsilon) were significantly reduced with stretch for both genders (p < 0.05). Females showed significantly (p < 0.05) greater pre- to poststretch decreases in K (22.4 vs. 8.8%) and epsilon (20.5 vs. 8.4%) in comparison to males. The present results show that stretching acutely reduces stiffness of the medial gastrocnemius tendon in females and males, with females showing significantly greater change. The observed disparity between genders may be due in part to variations in tendon moment arm and intrinsic differences in tendon composition. These differential changes in tendon mechanical properties have functional, motor control, and injury risk implications, as well as possible implications for preconditioning of tendon grafts. PMID:18942726

Burgess, Katherine E; Graham-Smith, Phillip; Pearson, Stephen J

2009-04-01

11

Structure and functional evaluation of tendon-skeletal muscle constructs engineered in vitro.  

PubMed

During muscle contraction, the integrity of the myotendinous junction (MTJ) is important for the transmission of force from muscle to tendon. We evaluated the contractile and structural characteristics of 3-dimensional (3-D) skeletal muscle constructs co-cultured with engineered self-organized tendon constructs (n = 4), or segments of adult (n = 4) or fetal (n = 5) rat-tail tendon. We hypothesized that the co-culture of tendon and muscle would produce constructs with viable muscle-tendon interfaces that remain intact during generation of force. Construct diameter (lm) and maximum isometric force (microN) were measured, and specific force (kPa) was determined. After measure of force, constructs were loaded at a constant strain rate until failure and surface strains were recorded optically across the tendon, the muscle and the interface and used to determine the tangent modulus (passive stiffness) of the construct. Frozen samples were used for Trichrome Masson staining and immunofluorescent analysis of the MTJ-specific protein paxillin. No differences were observed between the groups with respect to diameter, maximum force, or specific force. The MTJ was robust and withstood tensile loading beyond the physiological strain range. The majority of the constructs failed in the muscle region. At the MTJ, there is an increase in the expression and localization of paxillin. In conclusion, using 3 sources of tendon tissue, we successfully engineered 3-D muscle-tendon constructs with functionally viable MTJ, characterized by structural features and protein expression patterns resembling neonatal MTJs in vivo. PMID:17518629

Larkin, Lisa M; Calve, Sarah; Kostrominova, Tatiana Y; Arruda, Ellen M

2006-11-01

12

Collagen implants in experimental tendon injury in rabbits: a clinical, ultra-structural and biomechanical investigation.  

PubMed

This study investigated the effects of hybridized micro and nano structured collagen implants on tendon healing in an experimental tendon injury in rabbits. Fifty mature male New Zealand white rabbits were randomly divided into two groups of treated and control. Two cm of the left Achilles tendon were discarded. In the treated group, a 3-dimensional (3D) collagen implant was engineered and implanted in the defect area. No implant was used in the control group. At day 120 after injury, the Achilles tendon of the animals were ultrasonographically (days 0-120 after injury) and radiographically (day 120 after injury) examined, and the animals were euthanized. The tendons were dissected and used for gross pathological, histopathological, ultra-structural and biomechanical investigations. Application of the collagen implant significantly increased the diameter of the newly regenerated tissue in the defect area compared to the control tendons. Treatment also significantly increased the echogenicity and homogeneity of the injured area, the diameter of the collagen fibrils and fibers, maturity of the tenoblasts, number of tenocytes, collagen density, alignment, ultimate and yield load, stiffness, stress and modulus of elasticity. The collagen implants were almost totally absorbed 120 days after surgery. No inflammatory reaction or tissue degeneration or necrosis was evident in the treated tendons compared to the control ones. 3D collagen implants produced a newly regenerated tendinous tissue at the defect area that was morphologically and biomechanically superior to the control group. This collagen implant was biocompatible and biodegradable with high bio-safety in rabbits. PMID:25316127

Moshiri, A; Oryan, A; Meimandiparizi, A; Maffulli, N

2014-01-01

13

Tendon, tendon healing, hyperlipidemia and statins  

PubMed Central

Summary Both hyperlipidemia and metabolic syndrome have adverse effect on tendon structure. Atorvastatin is most widely used antihyperlipidemic drug. Statins have adverse effects on the tendon. Many studies have analyzed the relationship between atorvastatin and skeletal muscles. Atorvastatin administered after the surgical repair of a ruptured tendon appears to affect revascularization, collagenization, inflammatory cell infiltration, and collagen construction. Therefore, further investigations on the effects of atorvastatin on tendon healing are needed. PMID:23738266

Esenkaya, Irfan; Unay, Koray

2011-01-01

14

Structurally Integrated Fiber Optic Strain Sensing Prestressing Tendons within a New Road Bridge  

E-print Network

for steel in concrete structures there is considerable motivation to instrument test ·structures· · · Structurally Integrated Fiber Optic Strain Sensing Prestressing Tendons within a New Road FIBER OPTIC SMART STRUCTURES LABORATORY 4925 Dufterin St., Downsview, Ontario, CANADA * City of Calgary

15

Tendon healing: repair and regeneration.  

PubMed

Injury and degeneration of tendon, the soft tissue that mechanically links muscle and bone, can cause substantial pain and loss of function. This review discusses the composition and function of healthy tendon and describes the structural, biological, and mechanical changes initiated during the process of tendon healing. Biochemical pathways activated during repair, experimental injury models, and parallels between tendon healing and tendon development are emphasized, and cutting-edge strategies for the enhancement of tendon healing are discussed. PMID:22809137

Voleti, Pramod B; Buckley, Mark R; Soslowsky, Louis J

2012-01-01

16

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

NASA Astrophysics Data System (ADS)

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.

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

2009-03-01

17

Experimental Diabetes Induces Structural, Inflammatory and Vascular Changes of Achilles Tendons  

PubMed Central

This study aims to demonstrate how the state of chronic hyperglycemia from experimental Diabetes Mellitus can influence the homeostatic imbalance of tendons and, consequently, lead to the characteristics of tendinopathy. Twenty animals were randomly divided into two experimental groups: control group, consisting of healthy rats and diabetic group constituted by rats induced to Diabetes Mellitus I. After twenty-four days of the induction of Diabetes type I, the Achilles tendon were removed for morphological evaluation, cellularity, number and cross-sectional area of blood vessel, immunohistochemistry for Collagen type I, VEGF and NF-?B nuclear localization sequence (NLS) and nitrate and nitrite level. The Achilles tendon thickness (m/100g) of diabetic animals was significantly increased and, similarly, an increase was observed in the density of fibrocytes and mast cells in the tendons of the diabetic group. The average number of blood vessels per field, in peritendinous tissue, was statistically higher in the diabetic group 3.39 (2.98) vessels/field when compared to the control group 0.89 (1.68) vessels/field p?=?0.001 and in the intratendinous region, it was observed that blood vessels were extremely rare in the control group 0.035 (0.18) vessels/field and were often present in the tendons of the diabetic group 0.89 (0.99) vessels/field. The immunohistochemistry analysis identified higher density of type 1 collagen and increased expression of VEGF as well as increased immunostaining for NF?B p50 NLS in the nucleus in Achilles tendon of the diabetic group when compared to the control group. Higher levels of nitrite/nitrate were observed in the experimental group induced to diabetes. We conclude that experimental DM induces notable structural, inflammatory and vascular changes in the Achilles tendon which are compatible with the process of chronic tendinopathy. PMID:24130676

de Oliveira, Rodrigo R.; Martins, Conceio S.; Rocha, Yuri R.; Braga, Allysson B. R.; Mattos, Rmulo M.; Hecht, Fbio; Brito, Gerly A. C.; Nasciutti, Luiz E.

2013-01-01

18

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

PubMed

This study aims to demonstrate how the state of chronic hyperglycemia from experimental Diabetes Mellitus can influence the homeostatic imbalance of tendons and, consequently, lead to the characteristics of tendinopathy. Twenty animals were randomly divided into two experimental groups: control group, consisting of healthy rats and diabetic group constituted by rats induced to Diabetes Mellitus I. After twenty-four days of the induction of Diabetes type I, the Achilles tendon were removed for morphological evaluation, cellularity, number and cross-sectional area of blood vessel, immunohistochemistry for Collagen type I, VEGF and NF-?B nuclear localization sequence (NLS) and nitrate and nitrite level. The Achilles tendon thickness (m/100g) of diabetic animals was significantly increased and, similarly, an increase was observed in the density of fibrocytes and mast cells in the tendons of the diabetic group. The average number of blood vessels per field, in peritendinous tissue, was statistically higher in the diabetic group 3.39 (2.98) vessels/field when compared to the control group 0.89 (1.68) vessels/field p?=?0.001 and in the intratendinous region, it was observed that blood vessels were extremely rare in the control group 0.035 (0.18) vessels/field and were often present in the tendons of the diabetic group 0.89 (0.99) vessels/field. The immunohistochemistry analysis identified higher density of type 1 collagen and increased expression of VEGF as well as increased immunostaining for NF?B p50 NLS in the nucleus in Achilles tendon of the diabetic group when compared to the control group. Higher levels of nitrite/nitrate were observed in the experimental group induced to diabetes. We conclude that experimental DM induces notable structural, inflammatory and vascular changes in the Achilles tendon which are compatible with the process of chronic tendinopathy. PMID:24130676

de Oliveira, Rodrigo R; Martins, Conceio S; Rocha, Yuri R; Braga, Allysson B R; Mattos, Rmulo M; Hecht, Fbio; Brito, Gerly A C; Nasciutti, Luiz E

2013-01-01

19

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

PubMed Central

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 (<1 G) and regimens for muscle strengthening often employ hypergravity (>1 G) 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 (0.3 G peak-to-peak), and high vibration (2 G 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

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

2014-01-01

20

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

PubMed

Acute Achilles tendon ruptures are common sports injuries; however, treatment remains a clinical challenge. Studies show a superior effect of early mobilization and full weight bearing on tendon healing and clinical outcome; however, few data exist on structural and biomechanical characteristics in the early healing phase. This study investigated the histological and biomechanical characteristics of early mobilization and full weight bearing in an Achilles tendon rupture model. Eighty rats underwent dissection of a hindpaw Achilles tendon; 40 rats were treated conservatively and 40 underwent open repair of the transected Achilles tendon by suturing. Early mobilization and full weight bearing were allowed in both groups. At 1, 2, 4, and 8 weeks after tenotomy, tensile strength, stiffness, thickness, tissue characteristics (histological analysis), and length were determined. Dissected Achilles tendons healed in all animals during full weight-bearing early mobilization. One and 2 weeks after tenotomy, rats in the operative group showed increased tensile strength and stiffness compared with the nonoperative group. Repair-site diameters were increased at 1, 2, and 8 weeks after tenotomy. Tendon length was decreased in the operative group throughout observation, whereas the nonoperative group showed increased structural characteristics on the cellular level and a more homogeneous collagen distribution. Surgical treatment of dissected rat Achilles tendons showed superior biomechanical characteristics within the first 2 weeks. Conservative treatment resulted in superior histological findings but significant lengthening of the tendon in the early healing phase (weeks 1-8). PMID:22955406

Krapf, Daniel; Kaipel, Martin; Majewski, Martin

2012-09-01

21

Health monitoring of prestressing tendons in post-tensioned concrete structures  

NASA Astrophysics Data System (ADS)

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.

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

2011-04-01

22

Tendon structural and mechanical properties do not differ between genders in a healthy community-dwelling elderly population.  

PubMed

Elderly women are reportedly at higher risk of falling than their male counterparts. Postural balance is highly associated with fall risk and is also correlated with tendon structural and mechanical properties. Gender differences in tendon properties could partly explain the discrepancy in fall risk. Thus the purpose of this study was to investigate the possible gender difference in tendon properties in the elderly. The properties of the patellar tendon of 55 elderly (men n = 27, aged 72 +/- 1 years, women n = 28, aged 70 +/- 1 years) participants were tested. Tendon stiffness (K), length (L), and cross-sectional area (CSA) were measured using B-mode ultrasonography, dynamometry, and electromyography during ramped isometric knee extensions. There were no significant differences (p > 0.05) between men and women in tendon stiffness (elderly men 550.9 +/- 29.2 vs. women 502.9 +/- 44.9 Nmm(-1)) or in Young's modulus (elderly men 0.32 +/- 0.02 vs. women 0.36 +/- 0.04 GPa). This elderly group had similar tendon structural and mechanical properties. The comparable characteristics in gender-specific tendon properties in an elderly population exhibiting similar lifestyle characteristics to the current sample may not explain the reports in the literature regarding increased fall risk in elderly women relative to that seen in men of a similar age. PMID:19058184

Burgess, K E; Pearson, S J; Breen, L; Onambl, G N L

2009-06-01

23

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

NASA Astrophysics Data System (ADS)

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.

Jarau, Stefan; ?ek, Petr; obotnk, Jan; Vrkoslav, Vladimr; Hadravov, Romana; Coppe, Audrey; Va?kov, So?a; Jiro, Pavel; Valterov, Irena

2012-12-01

24

Achilles Tendonitis  

MedlinePLUS

... you ever worry about getting injured while playing sports? If the tendon becomes swollen or irritated due ... Causes Achilles Tendonitis? Achilles tendonitis is a common sports injury caused by repeated or intense strain on ...

25

Refixation of the supraspinatus tendon in a rat model--influence of continuous growth factor application on tendon structure.  

PubMed

The purpose was to evaluate histological changes of the supraspinatus tendon (SSP) after refixation under continuous growth factor application over 20 days in comparison to the native healing process. In a chronic rat tendon tear model (15 rats/group), a transosseous SSP refixation was performed and growth factors (control, G-CSF, b-FGF, combination) were continuously released into the subacromial space by an osmotic pump. Tendon healing was evaluated histologically by a modified MOVIN-Score, and Collagen I/III content was determined by immunohistology at 6 weeks. A modified MOVIN sum score showed significant lower counts for G-CSF and b-FGF in comparison to the control group (p = 0.050/p = 0.027) and the combined group (p = 0.050/p = 0.043). Collagen III was significantly reduced in the combined group compared to the control group (p = 0.028). Collagen I showed no significant differences. The Collagen I/III ratio was nearly doubled for b-FGF and the combined group compared to the control. At the study endpoint, 33% of pump dislocations were detected. The continuous application of both isolated growth factors (G-CSF/b-FGF) achieved improved tendon-remodeling. However, the continuous application via an osmotic pump showed a relative high dislocation rate when applied in the rat model. PMID:22912341

Buchmann, Stefan; Sandmann, Gunther H; Walz, Lars; Hoppe, Henriette; Beitzel, Knut; Wexel, Gabriele; Tian, Weiwei; Winter, Gerhard; Imhoff, Andreas B

2013-02-01

26

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

NASA Astrophysics Data System (ADS)

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.

Nigdeli, Sinan Melih; Boduro?lu, M. Hasan

2013-10-01

27

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

PubMed Central

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;3:25261. PMID:25106417

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

2014-01-01

28

Tendon repair  

MedlinePLUS

... free) The surgeon makes a cut on the skin over the injured tendon. The damaged or torn ends of the tendon are sewn together. If the tendon has been severely injured, a tendon graft may be needed. In this case, a piece ...

29

Effect of altered mechanical load conditions on the structure and function of cultured tendon fascicles.  

PubMed

We have developed an in vitro model system to investigate the relationships between mechanical unloading and tendon matrix remodeling. Remodeling was characterized by changes in the functional and structural characteristics of rat tail tendon fascicles (RTTF) subjected to no load conditions for 1 week in vitro. We hypothesized that the absence of load will: (I) maintain cross-sectional area (CSA), with decreased elastic modulus and increased stress-relaxation; (II) cause an increase in denatured collagen and a decrease in water and total glycosaminoglycan (GAG) content. Fascicles cultured under a nominal static stress were used as control for culture conditions effects. Unloading resulted in a decrease of approximately 23% in the elastic modulus of cultured fascicles, consistent with previous stress-deprivation studies. Contrary to our hypothesis, a nominal static stress caused an increase in elastic modulus ( approximately 30%) and a significant decrease in stress-relaxation when compared to fresh fascicles at 1% strain. Mechanical changes were associated with changes in the GAG content of the fascicles, but not their CSA, water, or collagen content. Furthermore, we did not find evidence of measurable denatured collagen in the cultured fascicles. Together these results suggest a role for GAG but not collagen or water in the elastic and viscoelastic changes measured in tendon fascicles cultured for 1 week under altered load conditions. PMID:17972327

Abreu, Eduardo L; Leigh, Diane; Derwin, Kathleen A

2008-03-01

30

Tendon and ligament imaging  

PubMed Central

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

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

2012-01-01

31

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

PubMed Central

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 patellas 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

Pitsillides, Andrew A.; Hutchinson, John R.

2014-01-01

32

Gender-specific in vivo measurement of the structural and mechanical properties of the human patellar tendon.  

PubMed

Human patellar tendon stress (sigma), strain (epsilon), stiffness (K), and tensile or Young's modulus (E), are determined in vivo through voluntary isometric contractions monitored with B-mode ultrasonography. The limitations in previous studies are: (1) they have generally not accounted for the fact that the distal attachment of the patellar tendon (the tibial tuberosity) also displaces; thus, they have underestimated epsilon (and, hence, injury risk) while overestimating K; (2) no gender effect has been studied despite the fact that females are seen to have higher incidences of tendon-related injuries. The current investigation therefore aimed to determine the gender specific values of sigma, epsilon, K, and E of the patellar tendon while also accounting for distal displacement of the patellar tendon. Healthy young males (aged 23.1 +/- 1.3 years, n = 10) and females (aged 21.3 +/-0.9 years, n = 10) were tested. The maximal epsilon of the young males was approximately 5-10% higher than that reported in earlier literature. Average female versus male values for epsilon, sigma, K, and E, taken at the same force level as the males for comparison purposes, were respectively 10.6 +/- 1.0 versus 9.0 +/- 1.0%, 36.9 +/- 1.4 versus 28.9 +/- 0.9 MPa, 1053 +/- 108 versus 1652 +/- 216 N x mm(-1), and 0.61 +/- 0.08 versus 0.68 +/- 0.10 GPa (p < 0.05). There are gender differences in tendon structural and mechanical properties. The current methodology may be useful in a clinical context where early prediction of injury risk and/or monitoring of reconstructed tendon needs to be an accurate, objective, and reliable method if optimal functionality is to be achieved. PMID:17568426

Onambl, Gladys N L; Burgess, Katherine; Pearson, Stephen J

2007-12-01

33

Neuronal regulation of tendon homoeostasis  

PubMed Central

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

Ackermann, Paul W

2013-01-01

34

The effect of the Achilles tendon on trabecular structure in the primate calcaneus.  

PubMed

Humans possess the longest Achilles tendon relative to total muscle length of any primate, an anatomy that is beneficial for bipedal locomotion. Reconstructing the evolutionary history of the Achilles tendon has been challenging, in part because soft tissue does not fossilize. The only skeletal evidence for Achilles tendon anatomy in extinct taxa is the insertion site on the calcaneal tuber, which is rarely preserved in the fossil record and, when present, is equivocal for reconstructing tendon morphology. In this study, we used high-resolution three-dimensional microcomputed tomography (micro-CT) to quantify the microstructure of the trabecular bone underlying the Achilles tendon insertion site in baboons, gibbons, chimpanzees, and humans to test the hypothesis that trabecular orientation differs among primates with different tendon morphologies. Surprisingly, despite their very different Achilles tendon lengths, we were unable to find differences between the trabecular properties of chimpanzee and human calcanei in this specific region. There were regional differences within the calcaneus in the degree of anisotropy (DA) in both chimpanzees and humans, though the patterns were similar between the two species (higher DA inferiorly in the calcaneal tuber). Our results suggest that while trabecular bone within the calcaneus varies, it does not respond to the variation of Achilles tendon morphology across taxa in the way we hypothesized. These results imply that internal bone architecture may not be informative for reconstructing Achilles tendon anatomy in early hominins. PMID:23821323

Kuo, Sharon; Desilva, Jeremy M; Devlin, Maureen J; McDonald, Gabriel; Morgan, Elise F

2013-10-01

35

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

PubMed Central

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

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

2012-01-01

36

Does aerobic exercise training promote changes in structural and biomechanical properties of the tendons in experimental animals? A systematic review.  

PubMed

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

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

2012-12-01

37

Bridging tendon defects using autologous tenocyte engineered tendon in a hen model.  

PubMed

Tendon defects remain a major concern in plastic surgery because of the limited availability of tendon autografts. Whereas immune rejection prohibits the use of tendon allografts, most prosthetic replacements also fail to achieve a satisfactory long-term result of tendon repair. The tissue engineering technique, however, can generate different tissues using autologous cells and thus may provide an optimal approach to address this concern. The purpose of this study was to test the feasibility of engineering tendon tissues with autologous tenocytes to bridge a tendon defect in either a tendon sheath open model or a partial open model in the hen. In a total of 40 Leghorn hens, flexor tendons were harvested from the left feet and were digested with 0.25% type II collagenase. The isolated tenocytes were expanded in vitro and mixed with unwoven polyglycolic acid fibers to form a cell-scaffold construct in the shape of a tendon. The constructs were wrapped with intestinal submucosa and then cultured in Dulbecco's Modified Eagle Medium plus 10% fetal bovine serum for 1 week before in vivo transplantation. On the feet, a defect of 3 to 4 cm was created at the second flexor digitorum profundus tendon by resecting a tendon fragment. The defects were bridged either with a cell-scaffold construct in the experimental group ( n= 20) or with scaffold material alone in the control group ( n= 20). Specimens were harvested at 8, 12, and 14 weeks postrepair for gross and histologic examination and for biomechanical analysis. In the experimental group, a cordlike tissue bridging the tendon defect was formed at 8 weeks postrepair. At 14 weeks, the engineered tendons resembled the natural tendons grossly in both color and texture. Histologic examination at 8 weeks showed that the neo-tendon contained abundant tenocytes and collagen; most collagen bundles were randomly arranged. The undegraded polyglycolic acid fibers surrounded by inflammatory cells were also observed. At 12 weeks, tenocytes and collagen fibers became longitudinally aligned, with good interface healing to normal tendon. At 14 weeks, the engineered tendons displayed a typical tendon structure hardly distinguishable from that of normal tendons. Biomechanical analysis demonstrated increased breaking strength of the engineered tendons with time, which reached 83 percent of normal tendon strength at 14 weeks. In the control group, polyglycolic acid constructs were mostly degraded at 8 weeks and disappeared at 14 weeks. However, the breaking strength of the scaffold materials accounted for only 9 percent of normal tendon strength. The results of this study indicated that tendon tissue could be engineered in vivo to bridge a tendon defect. The engineered tendons resembled natural tendons not only in gross appearance and histologic structure but also in biomechanical properties. PMID:12360068

Cao, Yilin; Liu, Yongtao; Liu, Wei; Shan, Qingxin; Buonocore, Samuel D; Cui, Lei

2002-10-01

38

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

PubMed

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

Konrad, A; Gad, M; Tilp, M

2014-04-10

39

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

PubMed

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

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

2014-07-01

40

Investigating load relaxation mechanics in tendon.  

PubMed

Tendons are hierarchical fibre composite materials, designed for the efficient transfer of force from muscles to the skeleton. As such, they exhibit high tensile strength, as well as complex viscoelastic and anisotropic characteristics. Although the viscoelastic behaviour has received considerable attention, the mechanisms by which the tendon structure facilitates this behaviour are less well understood. This study examines viscoelasticity within isolated tendon fascicles, using stress relaxation tests to examine how the matrix acts to dissipate load during the relaxation period. The fascicle behaviour during incremental and direct load relaxation tests was examined, using mechanical testing and confocal microscopy to assess the load and structural responses of the tendon, respectively. Results provide further evidence of the highly viscoelastic nature of tendon, and also demonstrate that relaxation behaviour within isolated tendon fascicles is dominated by fibre sliding mechanisms. These data indicate an important functional role for proteoglycans, in controlling the viscoelastic behaviour and the mechanisms of strain transfer within tendon. PMID:19627771

Screen, Hazel R C

2008-01-01

41

Silk and collagen scaffolds for tendon reconstruction.  

PubMed

In this study, silk thread (Bombyx mori) was braided to a tube-like shape and sericin was removed from the silk tube. Thereafter, collagen/chondroitin-6-sulfate solution was poured into the silk tube, and the lyophilization process was performed. To assess the inflammatory response in vivo, raw silk and sericin-free silk tubes were implanted in the subcutaneous layer of mice. After 10 days of in vivo implantation, mild inflammatory responses were observed around the sericin-free silk tubes, and severe inflammation with the presence of neutrophils and macrophages was observed around the raw silk tubes. At 24 weeks post implantation, the regenerated tendon had a thick, cylindrical, grayish fibrous structure and a shiny white appearance, similar to that of the native tendon in the rabbit model of tendon defect. The average tensile strength of the native tendons was 220 20 N, whereas the average tensile strength of the regenerated tendons was 167 30 N and the diameter of the regenerated tendon (3 0.2 mm) was similar to that of the native tendons (4 0.3 mm). Histologically, the regenerated tendon resembled the native tendon, and all the regenerated tissues showed organized bundles of crimped fibers. Masson trichrome staining was performed for detecting collagen synthesis, and it showed that the artificial tendon was replaced by new collagen fibers and extracellular matrix. However, the regenerated tendon showed fibrosis to a certain degree. In conclusion, the artificial tendon, comprising a braided silk tube and lyophilized collagen sponge, was optimal for tendon reconstruction. Thus, this study showed an improved regeneration of neo-tendon tissues, which have the structure and tensile strength of the native tendon, with the use of the combination of collagen and silk scaffold. PMID:24705339

Kwon, Soon-Yong; Chung, Jin-Wha; Park, Hee-Jung; Jiang, Yuan-Yuan; Park, Jung-Keug; Seo, Young-Kwon

2014-04-01

42

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

PubMed

Previous research has highlighted the importance of muscle and tendon structure to stretch shortening cycle performance. However, the relationships between muscle and tendon structure to performance are highly dependent on the speed and intensity of the movement. The purpose of this study was to determine if muscle and tendon structure is associated with the rate of force development (RFD) throughout static squat jump (SJ), countermovement jump (CMJ), and drop jump (DJ; 30-cm height). Twenty-five strength- and power-trained men participated in the study. Using ultrasonography, vastus lateralis (VL) and gastrocnemius (GAS) pennation (PEN) and fascicle length (FL), and Achilles tendon (AT) thickness and length were measured. Subjects then performed SJ, CMJ, and DJ, during which RFD was calculated over time 5 distinct time intervals. During CMJs, early RFD could be predicted between 0 and 10 milliseconds by both GAS-FL (r = 0.213, ? = 0.461) and AT-length (r = 0.191, ? = 20.438). Between 10 and 30 milliseconds GAS-FL was a significant predictor of CMJ-RFD (r = 0.218, ? = 0.476). During DJ, initial RFD (0-10 milliseconds) could be significantly predicted by GAS-FL (r = 0.185, ? = 20.434), VL-PEN (r = 0.189, ? = 0.435), and GAS-PEN (r = 0.188, ? = 0.434). These findings suggest that longer ATs may have increased elasticity, which can decrease initial RFD during CMJ; thus, their use in talent identification is not recommended. The GAS fascicle length had an intensity-dependent relationship with RFD, serving to positively predict RFD during early CMJs and an inverse predictor during early DJs. During DDJs, subjects with greater PEN were better able to redirected initial impact forces. Although both strength and plyometric training have been shown to increase FL, only heavy strength training has been shown to increase PEN. Thus, when a high eccentric load or multiple jumps are required, heavy strength training might be used to elicit muscular adaptations that are suited to fast force production during jumping. PMID:21322836

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

2011-02-01

43

Effects of 20 days of bed rest on the viscoelastic properties of tendon structures in lower limb muscles  

PubMed Central

Objectives: The purpose of this study was to investigate the effects of 20 days' bed rest on the viscoelastic properties of human tendon structures in knee extensor and plantar flexor muscles in vivo. Methods: Eight healthy men (age: 244 years, height: 1729 m, body mass: 6913 kg) carried out a 6 head-down bed rest for 20 days. Before and after bed rest, elongation (L) of the tendon and aponeurosis of vastus lateralis (VL) and medial gastrocnemius muscles (MG) during isometric knee extension and plantar flexion, respectively, were determined using real-time ultrasonic apparatus, while the subjects performed ramp isometric contraction up to the voluntary maximum, followed by ramp relaxation. The relationship between estimated muscle force (Fm) and tendon elongation (L) was fitted to a linear regression, the slope of which was defined as stiffness. The hysteresis was calculated as the ratio of the area within the Fm-L loop to the area beneath the load portion of the curve. Results: L values above 100 N were significantly greater after bed rest for VL, while there were no significant differences in L values between before and after for MG. The stiffness decreased after bed rest for VL (70.327.4 v 50.124.8 N/mm, before and after bed rest, respectively; p = 0.003) and MG (29.47.5 v 25.67.8 N/mm, before and after bed rest, respectively; p = 0.054). In addition, hysteresis increased after bed rest for VL (16.57.1% v 28.212.9%, before and after bed rest, respectively; p = 0.017), but not for MG (17.44.4% v 17.76.1%, before and after bed rest, respectively; p = 0.925). Conclusions: These results suggested that bed rest decreased the stiffness of human tendon structures and increased their hysteresis, and that these changes were found in knee extensors, but not the plantar flexors. PMID:15155437

Kubo, K; Akima, H; Ushiyama, J; Tabata, I; Fukuoka, H; Kanehisa, H; Fukunaga, T

2004-01-01

44

Mesenchymal stem cell applications to tendon healing  

PubMed Central

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

Chaudhury, Salma

2012-01-01

45

Research on reasonable position of FRP tendons in concrete beams prestressed with bonded and\\/or unbonded FRP tendons  

Microsoft Academic Search

Fiber reinforcement polymers (FRPs) have high strength; they are well suited for prestressing tendons in corrosive environment. Concrete structures prestressed with FRP tendons usually exhibit brittle failure models due to the brittle nature of the FRP composites. Based on different mechanical properties of prestressed concrete structures, a combination of bonded and\\/or unbonded prestressing tendons was used in order to improve

Zuohu Wang; Xiuli Du

2011-01-01

46

Ultrasound of tendons and nerves.  

PubMed

Tendons and nerves represent probably one of the best application of musculoskeletal US due to the high lesion detection rate and accuracy of US combined with its low cost, wide availability, and ease of use. The refinement of high-frequency broadband linear-array transducers, and sensitive color and power Doppler technology, have improved the ability of US to detect fine textural abnormalities of these structures as well as to identify a variety of pathological conditions. Characteristic echotextural patterns, closely resembling the histological ones, are typically depicted in these structures using high US frequencies. In tendon imaging, US can assess dislocations, degenerative changes and tendon tears, including intrasubstance tears, longitudinal splits, partial and complete rupture, inflammatory conditions and tendon tumors, as well as postoperative findings. In nerve imaging, US can support clinical and electrophysiological testing for detection of compressing lesions caused by nerve entrapment in a variety of osteofibrous tunnels of the limbs and extremities. Congenital anomalies, nerve tears, and neurogenic tumors can also be diagnosed. Overall, US is an effective technique for imaging tendons and nerves. In most cases, a focused US examination can be performed more rapidly and efficiently than MR imaging. PMID:11868073

Martinoli, Carlo; Bianchi, Stefano; Dahmane, M'Hamed; Pugliese, Francesca; Bianchi-Zamorani, Maria Pia; Valle, Maura

2002-01-01

47

Tendon crimps and peritendinous tissues responding to tensional forces.  

PubMed

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

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

2007-01-01

48

The Effect of Tendon Surface Treatment on Cell Attachment for Potential Enhancement of Tendon Graft Healing: An Ex Vivo Model  

PubMed Central

For both tendon allografts and autografts, the surface, initially optimized for gliding, may not be ideal to facilitate tissue integration for graft healing to host tendon or bone. As a prelude to studying tendon-bone integration, we investigated the effect of surface treatments with trypsin or mechanical abrasion on cell attachment to the tendon surface in a canine ex vivo intrasynovial tendon tissue culture model. Intrasynovial tendon allograft surfaces were seeded with cells after the following treatments: 1) no treatment, 2) mechanical abrasion, 3) trypsin, 4) abrasion and trypsin. The area covered by cells was determined using confocal laser microscopy at one and two weeks. Results were compared to untreated extrasynovial tendon. Additional tendons were characterized with scanning electron microscopy. Tendons with trypsin treatment had significantly more surface coverage with cells than the other groups, after both one and two weeks of culture. In terms of the cellular shape and size, cells on tendons with trypsin treatment spread more and were more polygonal in shape, whereas tendons with mechanical abrasion with/without trypsin treatment contained smaller, more spindle-like cells. Surface roughening can affect cell behavior with topographical stimulation. Trypsin surface digestion exposes a mesh-like structure on the tendon surface, which could enhance cell adherence and, possibly, tendon/bone healing. PMID:22349134

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

2012-01-01

49

Diseases of the tendons and tendon sheaths.  

PubMed

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

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

2014-03-01

50

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

Microsoft Academic Search

The glycosaminoglycan (GAG) side-chains of small leucine-rich proteoglycans have been postulated to mechanically cross-link adjacent collagen fibrils and contribute to tendon mechanics. Enzymatic depletion of tendon GAGs (chondroitin and dermatan sulfate) has emerged as a preferred method to experimentally assess this role. However, GAG removal is typically incomplete and the possibility remains that extant GAGs may remain mechanically functional. The

Gion Fessel; Jess G. Snedeker

2011-01-01

51

Peroneal Tendon Injuries  

MedlinePLUS

... ACFAS | Informacin en Espaol 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 ...

52

Achilles tendon rupture - aftercare  

MedlinePLUS

Managing Your: Achilles Tendon Rupture. In: Ferri FF, ed. Ferri's Clinical Advisor 2015 . 1st ed. Philadelphia, PA: Mosby Elsevier; 2014: appendix V. Sokolove PE, Barnes DK. Extensor and Flexor Tendon Injuries ...

53

Tendon stem cells: experimental and clinical perspectives in tendon and tendon-bone junction repair  

PubMed Central

Summary Tendon and tendon-bone junction injuries, while heal, have high re-tear rates. Mesenchymal stem cells (MSCs) have great appeal for the promotion of tendon and tendon-bone junction healing because of their high proliferation rate, multi-potency and relative ease of isolation from various tissues. Tendon stem cells have been identified recently and could be an alternative new cell source for tendon and tendon-bone junction repair. In this review, we summarized the in vitro characteristics of tendon stem cells. The evidence supporting the potential use of these cells for tendon and tendon-bone junction repair was presented. In order to therapeutically apply tendon stem cells in the clinical settings, standardization of tendon stem cell culture is essential. Issues relating to the sources, purity, efficacy, safety and delivery of tendon stem cells for tendon and tendon-bone junction repair were summarized and discussed. The direction for future research was suggested. PMID:23738293

Lui, Pauline Po Yee; Wong, On Tik

2012-01-01

54

p38 MAPK Signaling in Postnatal Tendon Growth and Remodeling  

PubMed Central

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

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

2015-01-01

55

[Tendon rupture as a complication after osteosynthesis of distal radius].  

PubMed

Close contact between extensor and flexor tendons to the bone structure of the wrist and distal radius shaft implies the possibility of alteration concerning the tendons' slide way and tensile direction in case of osteosynthesis in this region. Even a slightly damaged screw is mechanically capable of irritation and can be made responsible for a scrub-necrosis of an above tendon. The metal implant has to be selected in consideration of both the demands of the fracture and a free and natural tendons pathway. This is discussed by means of two implant-induced scrub necroses of the long pollex extensor and flexor tendon. PMID:6516033

Lugger, L J; Pechlaner, S

1984-10-01

56

The role of animal models in tendon research  

PubMed Central

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;3:193202. PMID:24958818

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

2014-01-01

57

Relationship between compressive loading and ECM changes in tendons  

PubMed Central

Summary Tendons are designed to absorb and transfer large amounts of tensile load. The well organised, strong yet flexible, extracellular matrix allows for this function. Many tendons are also subject to compressive loads, such as at the entheses, as the tendon wraps around bony protuberances or from internal compression during tensile loading or twisting. Tendinopathy, the clinical syndrome of pain and dysfunction in a tendon is usually the result of overload. However, it is not only the tensile overload that should be considered, as it has been shown that compressive loads change tendon structure and that combination loads can induce tendon pathology. This review summarises how load is detected by the tenocytes, how they respond to compressive load and the resulting extracellular matrix changes that occur. Understanding the effect of compression on tendon structure and function may provide directions for future matrix based interventions. PMID:23885340

Docking, Sean; Samiric, Tom; Scase, Ebonie; Purdam, Craig; Cook, Jill

2013-01-01

58

Open extensor tendon injuries.  

PubMed

The extensor tendons in the dorsum of the hand lie relatively superficially, making open injuries to the extensor mechanism a common source of morbidity. These injuries can range from simple clean lacerations to complex open injuries associated with severe skin and soft tissue loss. Although many advances in the treatment of tendon injuries focused on the flexor tendon, the extensor tendon has begun to receive more attention in recent literature. Knowledge of modern repair techniques and rehabilitation protocols may improve patient outcomes. This Current Concepts article summarizes the treatment of open extensor tendon injuries with a focus on the recent literature. PMID:25557773

Amirtharajah, Mohana; Lattanza, Lisa

2015-02-01

59

Achilles tendon disorders.  

PubMed

Achilles tendon disorders include tendinosis, paratenonitis, insertional tendinitis, retrocalcaneal bursitis, and frank rupture. Patients present with pain and swelling in the posterior aspect of the ankle. Magnetic resonance imaging and ultrasound are helpful in confirming the diagnosis and guiding treatment. Nonsurgical management of Achilles tendon disorders includes nonsteroidal anti-inflammatory drugs, physical therapy, bracing, and footwear modification. Surgical treatment includes debridement of the diseased area of the tendon with direct repair. Tendon transfer may be necessary to augment the strength of the Achilles tendon. PMID:24559878

Weinfeld, Steven B

2014-03-01

60

Plantar tendons of the foot: MR imaging and US.  

PubMed

Tendon disorders along the plantar aspect of the foot may lead to significant symptoms but are often clinically misdiagnosed. Familiarity with the normal anatomy of the plantar tendons and its appearance at magnetic resonance (MR) imaging and ultrasonography (US) is essential for recognizing plantar tendon disorders. At MR imaging, the course of the plantar tendons is optimally visualized with dedicated imaging of the midfoot and forefoot. This imaging should include short-axis images obtained perpendicular to the long axis of the metatarsal shafts, which allows true cross-sectional evaluation of the plantar tendons. Normal plantar tendons appear as low-signal-intensity structures with all MR sequences. At US, accurate evaluation of the tendons requires that the ultrasound beam be perpendicular to the tendon. The normal tendon appears as a compact linear band of echogenic tissue that contains a fine, mixed hypoechoic and hyperechoic internal fibrillar pattern. Tendon injuries can be grouped into six major categories: tendinosis, peritendinosis, tenosynovitis, entrapment, rupture, and instability (subluxation or dislocation) and can be well assessed with both MR imaging and US. The radiologist plays an important role in the diagnosis of plantar tendon disorders, and recognizing their imaging appearances at MR imaging and US is essential. PMID:24224599

Donovan, Andrea; Rosenberg, Zehava Sadka; Bencardino, Jenny T; Velez, Zoraida Restrepo; Blonder, David B; Ciavarra, Gina A; Adler, Ronald Steven

2013-01-01

61

THE ROLE OF MECHANOBIOLOGY IN TENDON HEALING  

PubMed Central

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

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

2011-01-01

62

MRI 'magic angle' imaging of finger tendons.  

PubMed

The value of using the technique of magic angle MR imaging to demonstrate finger tendons is explored. Images of fresh frozen cadaveric specimens are presented and the structures that can be visualized in the finger are described. The results suggest that magic angle MR imaging may be a useful non-invasive technique of visualizing the details of the tendons and their surrounds in the hand. PMID:16182418

Lambe, G; Coutts, G; McArthur, P; Dangerfield, P H

2006-04-01

63

Crimp morphology in relaxed and stretched rat Achilles tendon.  

PubMed

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

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

2007-01-01

64

Effect of paratenon and repetitive motion on the gliding resistance of tendon of extrasynovial origin.  

PubMed

We measured the gliding resistance of canine and human tendons of intrasynovial origin and tendons of extrasynovial origin with and without paratenon, and investigated the structure of paratenon using scanning electron microscopy. In the canine study, seven intrasynovial flexor digitorum profundus (FDP) tendons, seven extrasynovial fibularis (peroneus) longus (FL) tendons with paratenon, and seven FL tendons without paratenon were used. In the human study, seven intrasynovial FDP tendons and seven extrasynovial palmaris longus (PL) tendons cut in half (one half with paratenon, the other half without paratenon) were used. The gliding resistance of each tendon was measured at 1, 5, 10, 20, 50, and100 flexion/extension cycles. The canine and human FDP tendons maintained a gliding resistance significantly lower than that of the other tendons at all observation points (P < 0.05). In the canine, the gliding resistance of the FL tendon with paratenon was significantly lower than that of the FL tendon without paratenon up to 50 flexion/extension cycles (P < 0.05), but the two were not significantly different at 100 cycles. In the human, the gliding resistance of PL tendons with paratenon was significantly lower than that of the PL tendons without paratenon at all measuring points (P < 0.05). Preservation of paratenon thus appears to decrease the gliding resistance of extrasynovial tendons after repetitive motion in vitro. PMID:11948955

Momose, Toshimitsu; Amadio, Peter C; Zobitz, Mark E; Zhao, Chunfeng; An, Kai-Nan

2002-05-01

65

Recruitment viscoelasticity of the tendon.  

PubMed

There is still no agreement on the nature of tissues' viscoelasticity and on its reliable modeling. We speculate that disagreements between previous observations stem from difficulties of separating between viscoelastic and preconditioning effects, since both are manifested by similar response features. Here, this and related issues were studied in the tendon as a prototype for other soft tissues. Sheep digital tendons were preconditioned under strain that was higher by 1% than the one used in subsequent testing. Each specimen was then subjected to stress relaxation, and quick release or creep. A stochastic microstructural viscoelastic theory was developed based on the collagen fibers' properties and on their gradual recruitment with stretch. Model parameters were estimated from stress relaxation data and predictions were compared with the creep data. Following its validation, the new recruitment viscoelasticity (RVE) model was compared, both theoretically and experimentally, with the quasilinear viscoelastic (QLV) theory. The applied preconditioning protocol produced subsequent pure viscoelastic response. The proposed RVE model provided excellent fit to both stress relaxation and creep data. Both analytical and numerical comparisons showed that the new RVE theory and the popular QLV one are equivalent under deformation schemes at which no fibers buckle. Otherwise, the equivalence breaks down; QLV may predict negative stress, in contrast to data of the quick release tests, while RVE predicts no such negative stress. The results are consistent with the following conclusions: (1) fully preconditioned tendon exhibits pure viscoelastic response, (2) nonlinearity of the tendon viscoelasticity is induced by gradual recruitment of its fibers, (3) a new structure-based RVE theory is a reliable representation of the tendon viscoelastic properties under both stress relaxation and creep tests, and (4) the QLV theory is equivalent to the RVE one (and valid) only under deformations in which no fibers buckle. The results also suggest that the collagen fibers themselves are linear viscoelastic. PMID:20353259

Einat, Raz; Yoram, Lanir

2009-11-01

66

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

PubMed Central

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

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

1990-01-01

67

[Flexor tendon repair: a short story].  

PubMed

This short story of flexor tendon repair aims to illustrate hesitations and wanderings of this surgery. Obviously tendon repair was very early considered, but it developed and diffused rather lately. It became a routine practice only in 20th century. This was due on the one hand, in Occident, to the Galen's dogmatic interdiction, on the other hand, to the repair difficulties of this paradoxical structure. Actually tendon is made of fibroblasts and collagen (sticky substances), and then its only goal is to move. According to this necessity, whatever the used techniques are, gliding is the final purpose. Technical evolutions are illustrated by historical contributions to flexor tendon surgery of several "giants" of hand surgery. PMID:24837978

Moutet, F; Corcella, D; Forli, A; Mesquida, V

2014-12-01

68

Fatigue loading of tendon  

PubMed Central

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

Shepherd, Jennifer H; Screen, Hazel R C

2013-01-01

69

The palmaris longus tendon  

Microsoft Academic Search

The palmaris longus is one of the most variable muscles of the human body. An understanding of its variations is useful as it is often used as a tendon graft and for tendon transfer. We report another interesting variation in its anatomy.

C. C. Koo; A. H. N. Roberts

1997-01-01

70

Mechanical properties of the human achilles tendon  

Microsoft Academic Search

Objective. To determine whether the human Achilles tendon has higher material properties than other tendons and to test for strain rate sensitivity of the tendon.Design. Mechanical testing of excised tendons.Background. While the human Achilles tendon appears to experience higher in vivo stresses than other tendons, it is not known how the Achilles tendon's material properties compare with the properties of

Tishya A. L Wren; Scott A Yerby; Gary S Beaupr; Dennis R Carter

2001-01-01

71

The Achilles tendon: fundamental properties and mechanisms governing healing  

PubMed Central

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

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

2014-01-01

72

Tendon Gradient Mineralization for Tendon to Bone Interface Integration  

PubMed Central

Tendon-to-bone integration is a great challenge for tendon or ligament reconstruction regardless of use of autograft or allograft tendons. We mineralized the tendon, thus transforming the tendon-to-bone into a bone-to-bone interface for healing. Sixty dog flexor digitorum profundus (FDP) tendons were divided randomly into 5 groups: 1) normal FDP tendon, 2) CaP (Non-extraction and mineralization without fetuin), 3) CaPEXT (Extraction by Na2HPO4 and mineralization without fetuin), 4) CaPFetuin (Non-extraction and mineralization with fetuin), and 5) CaPEXTFetuin (Extraction and mineralization with fetuin). The calcium and phosphate content significantly increased in tendons treated with combination of extraction and fetuin compared to the other treatments. Histology also revealed a dense mineral deposition throughout the tendon outer layers and penetrated into the tendon to a depth of 200 ?m in a graded manner. Compressive moduli were significantly lower in the four mineralized groups compared with normal control group. No significant differences in maximum failure strength or stiffness were found in the suture pull-out test among all groups. Mineralization of tendon alters the interface from tendon to bone into mineralized tendon to bone, which may facilitate tendon-to-bone junction healing following tendon or ligament reconstruction. PMID:23939935

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

2014-01-01

73

Tendon injuries of the hand  

PubMed Central

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

Schffl, Volker; Heid, Andreas; Kpper, Thomas

2012-01-01

74

Mechanical characteristics of native tendon slices for tissue engineering scaffold.  

PubMed

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

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

2012-04-01

75

Tendon Transfer Surgery  

MedlinePLUS

... stroke, traumatic brain injuries, and spinal muscle atrophy. Finally, there are some conditions in which babies are ... therapy to teach you the new tendon function. Finally, exercises will be needed to strengthen the muscle ...

76

Percutaneous Achilles Tendon Lengthening  

MedlinePLUS

... Bulk Allograft Transplantation for Osteochondral Lesions of the Talus Insertional Achilles Tendinosis Surgery Lateral Ankle Ligament Reconstruction ... Ankle Stabilization Mosaicplasty for Osteochondral Lesions of the Talus Peroneus Longus to Achilles Tendon Transfer Pilon Fracture ...

77

The tendons: Interventional sonography  

PubMed Central

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

Campagna, R.; Guerini, H.

2012-01-01

78

Stiffness of reinforced concrete beams with external tendons  

Microsoft Academic Search

In recent years, external prestressing has become a primary method for strengthening existing concrete structures and has been increasingly used in the construction of newly erected ones, particularly segmental bridges. Analysis of externally prestressed members is more difficult than that of members with internal bonded tendons. This is because external tendons are unbonded to the concrete and the stress in

Bilal El-Ariss

2004-01-01

79

Specialisation of extracellular matrix for function in tendons and ligaments  

PubMed Central

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

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

2013-01-01

80

Demonstrating collagen tendon fibril segments involvement in intrinsic tendon repair  

PubMed Central

Severed tendons can undergo regenerative healing, intrinsic tendon repair. Fibrillogenesis of chick tendon involves collagen fibril segments (CFS), which are the building blocks of collagen fibers that make up tendon fascicles. The CFS are 10.5 micron in length, composed of tropocollagen monomers arranged in parallel arrays. Rather than incorporating single tropocollagen molecules into growing collagen fibers, incorporating large CFS units is the mechanism for generating collagen fibers. Is intrinsic tendon repair through the reestablishment of tendon embryogenesis? Gentamicin treated 10-day-old chick embryo tendons released CFS were fluorescently tagged with Rhodamine (Rh). Organ cultured severed 14-day-old embryo tendon explants received Rh tagged CFS. At day 4 auto fluorescent tagged CFS were identified at the severed tendon ends by fluorescent microscopy. Accumulation of fluorescent tagged CFS was exclusively localized to the severed ends of tendon explants. Parallels between collagen fiber growth during embryonic fibrillogenesis and tendon repair reveal CFS incorporation is responsible for collagen fibers growth. CFS incorporation into frayed collagen fibers from severed tendons is the proposed mechanism for intrinsic tendon repair, which is an example of regenerative repair. PMID:21855540

Hazard, Sprague W.; Myers, Roland L.; Ehrlich, H. Paul

2011-01-01

81

Flexor TendonTendon Sheath Interaction After Tendon Grafting: A Biomechanical Study in a Human Model In Vitro  

Microsoft Academic Search

A human cadaver tendon sheath model was used to study the differences in excursion resistance of tendons that might be considered as sources of clinical tendon grafts. The flexor digitorum profundus and superficialis tendons, the extensor indicis proprius tendon used in its normal proximal-distal orientation, the extensor indicis proprius tendon used in a reversed distalproximal orientation, and the palmaris longus

Jun Nishida; Peter C. Amadio; Paul C. Bettinger; Kai-Nan An

1999-01-01

82

Biodegradable synthetic scaffolds for tendon regeneration  

PubMed Central

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

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

2012-01-01

83

Relationship between tendon stiffness and failure: a metaanalysis.  

PubMed

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

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

2013-07-01

84

Stem Cell Applications in Tendon Disorders: A Clinical Perspective  

PubMed Central

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

Young, Mark

2012-01-01

85

Striated muscle fiber apoptosis after experimental tendon lesion in a rat model  

PubMed Central

Tendon lesions induce muscular atrophy, the nature of which has not yet been clearly related to lesion etiology and entity. In the present study, tendon and muscle alterations were assessed after experimental tendon lesion of the Infraspinatus muscle in young rats. The consequences of lesions differed on the basis of both extension and injured tissue vascularization, that is apoptosis and/or degeneration, differing mainly by energy demands: apoptosis requires high energy levels (proportional to vascular supply), but degeneration does not. It is well known that tendons are poorly supplied with blood compared with muscular masses, which are abundantly vascularized. Five weeks after tendon surgical section, tendon/muscle samples were taken for TUNEL and transmission electron microscopy. The structural results reported here identified different tendon/muscle alterations: degeneration of tendon without signs of apoptosis, and atrophy of muscle fibers due only to apoptosis. This led to the formulation of the following hypothetical sequence of events: a tendon lesion, not recovering quickly due to the poor tendon blood supply, results in degeneration of the injured tendon, which, in turn, induces a partial disuse of the muscle mass, which consequently atrophies (proportionally to the severity of tendon lesion) by striated muscular fiber apoptosis. The authors suggest that the different behavior of the two tissues depends on the marked difference in their vascularization. PMID:22881388

Palumbo, Carla; Rovesta, Claudio; Ferretti, Marzia

2012-01-01

86

Open Achilles tendon lacerations.  

PubMed

In contrast to closed Achilles tendon ruptures, open injuries are rarely reported in the literature. This paper provides information about open Achilles tendon wounds that are eventually seen in the Middle East. The reporting unit, Hamad Medical Corporation, is one of the biggest trauma centers in the Gulf area and the major health provider in Qatar. This is a retrospective study including patients admitted and operated for open Achilles tendon injuries between January 2011 and December 2013. Two hundred and five cases of open Achilles tendon lacerations were operated in Hamad General Hospital in this period. Forty-eight cases showed partial injuries, and the remaining are complete tendons cut. In the same period, fifty-one closed ruptured Achilles tendons were operated in the same trauma unit. In the majority of cases, the open injury resulted from a slip in the floor-leveled traditional toilette seats. Local damage to the toilette seats resulted in sharp edges causing the laceration of the heel if the patient was slipping over the wet floor. This occurrence is the cause in the vast majority of the cases. Wounds were located 1-5cm proximal to tendon insertion. Standard treatment principles were applied. This included thorough irrigation in the emergency room, intravenous antibiotics, surgical debridement and primary repair within 24h. Patients were kept in the hospital 1-7days for intravenous antibiotics and possible dressing changes. Postoperatively below knee slabs were applied in the majority of patients and were kept for about 4weeks followed by gradual weight bearing and range of motion exercises. Outpatients follow up in 1-2weeks. Further follow-up visits at around 2-, 4-, 8- and 12-week intervals until complete wound healing and satisfactory rehabilitation outcome. Sixteen cases needed a second procedure. A high incidence of Achilles tendon open injuries is reported. This seems to be related to partially damaged floor-level toilettes in the typical Middle-East lavatory. The surgical treatment resulted in excellent outcome in the vast majority of the cases. Low incidence of complications resulted despite dramatic injury pattern. PMID:25337957

Said, M Nader; Al Ateeq Al Dosari, Mohamed; Al Subaii, Nasser; Kawas, Alaa; Al Mas, Ali; Al Ser, Yaser; Abuodeh, Yousef; Shakil, Malik; Habash, Ali; Mukhter, Khalid

2015-04-01

87

Collagen Fiber Re-Alignment in a Neonatal Developmental Mouse Supraspinatus Tendon Model  

PubMed Central

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, 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 supraspinatus tendon 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 tendons ability to structurally respond to load. Additionally, results indicate that the insertion site and tendon midsubstance locations develop differently. PMID:22183194

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

2012-01-01

88

Mesenchymal stem cells and insulin-like growth factor-I gene-enhanced mesenchymal stem cells improve structural aspects of healing in equine flexor digitorum superficialis tendons.  

PubMed

Tendinitis remains a catastrophic injury among athletes. Mesenchymal stem cells (MSCs) have recently been investigated for use in the treatment of tendinitis. Previous work has demonstrated the value of insulin-like growth factor-I (IGF-I) to stimulate cellular proliferation and tendon fiber deposition in the core lesion of tendinitis. This study examined the effects of MSCs, as well as IGF-I gene-enhanced MSCs (AdIGF-MSCs) on tendon healing in vivo. Collagenase-induced bilateral tendinitis lesions were created in equine flexor digitorum superficialis tendons (SDFT). Tendons were treated with 10 x 10(6) MSCs or 10 x 10(6) AdIGF-MSCs. Control limbs were injected with 1 mL of phosphate-buffered saline (PBS). Ultrasound examinations were performed at t = 0, 2, 4, 6, and 8 weeks. Horses were euthanized at 8 weeks and SDFTs were mechanically tested to failure and evaluated for biochemical composition and histologic characteristics. Expression of collagen types I and III, IGF-I, cartilage oligomeric matrix protein (COMP), matrix metalloproteinase-3 (MMP-3), matrix metalloproteinase-13 (MMP-13), and aggrecanase-1 (ADAMTS-4) were similar in MSC and control tendons. Both MSC and AdIGF-MSC injection resulted in significantly improved tendon histological scores. These findings indicate a benefit to the use of MSCs and AdIGF-MSCs for the treatment of tendinitis. PMID:19350658

Schnabel, Lauren V; Lynch, Maureen E; van der Meulen, Marjolein C H; Yeager, Amy E; Kornatowski, Matthew A; Nixon, Alan J

2009-10-01

89

Tenocyte contraction induces crimp formation in tendon-like tissue.  

PubMed

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

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

2012-03-01

90

Tendon to bone healing and its implications for surgery  

PubMed Central

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

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

2014-01-01

91

Conflicts, snapping and instability of the tendons. Pictorial essay  

PubMed Central

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

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

2012-01-01

92

Scaffolds in Tendon Tissue Engineering  

PubMed Central

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

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

2012-01-01

93

Tendon-driven manipulators: Analysis, synthesis, and control  

NASA Astrophysics Data System (ADS)

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

Lee, Jyh-Jone

94

Arthroscopic Treatment of Subscapularis Calcific Tendonitis  

PubMed Central

Rotator cuff tendonitis is a very common diagnosis of the shoulder that usually responds to conservative management. However, calcific tendonitis occurs less frequently and often necessitates surgical intervention. The etiology and treatment options for this disorder remain controversial among orthopaedic shoulder specialists. Calcific tendonitis frequently presents within the supraspinatus tendon and rarely appears within the subscapularis tendon. We present a case and accompanying video technique of arthroscopic treatment of subscapularis calcific tendonitis. PMID:25473608

Fields, Logan K.; Muxlow, Chad J.; Caldwell, Paul E.

2014-01-01

95

Arthroscopic Treatment of Calcific Tendonitis  

PubMed Central

Calcific tendonitis, or calcifying tendonitis, is a common disorder characterized by the multifocal accumulation of basic calcium phosphate crystals within the rotator cuff tendons. In most cases, the multifocal calcifications are located 1 to 2 cm from the insertion of the supraspinatus tendon on the greater tuberosity. The initial treatment should be nonoperative including oral anti-inflammatory medication and physical therapy. If this is unsuccessful, arthroscopic debridement of the deposit is effective. The technique used is an arthroscopic localization and debridement without associated subacromial decompression. The rotator cuff should be evaluated for partial- and full-thickness tears before and after the debridement of calcifications. If a partial- or full-thickness rotator cuff tendon tear is identified, it should be treated in a fashion consistent with those without associated calcium deposits. In our hands, tears 5 mm or greater in depth are repaired using a tendon-to-tendon or tendon-to-bone technique. Tears with less depth are debrided and then left alone. Arthroscopic debridement of calcific tendonitis can yield excellent functional results and high patient satisfaction. PMID:24904767

Barber, F. Alan; Cowden, Courtney H.

2014-01-01

96

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

PubMed

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 2cm defect was created on right side of Achilles tendon followed by the transplantation of a 3cm cell-seeded scaffold in the experimental group of 15 rabbits, or by the transplantation of a 3cm 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 50MPa 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

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

2014-10-01

97

Mineral distributions at the developing tendon enthesis.  

PubMed

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 m) 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

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

2012-01-01

98

Mineral Distributions at the Developing Tendon Enthesis  

PubMed Central

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 m) 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

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

2012-01-01

99

Cellular therapy in bone-tendon interface regeneration  

PubMed Central

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

Rothrauff, Benjamin B; Tuan, Rocky S

2014-01-01

100

Tendon conditioning: artefact or property?  

PubMed Central

Isolated tendons subjected to cyclic tensile loads higher than those experienced in the tendons' recent history exhibit 'conditioning', i.e. gradually increasing elongations upon loading and gradually increasing residual elongations after unloading in the first few loading-unloading cycles. The present study examines whether this behaviour is a measurement artefact or an actual time-dependent property. The gastrocnemius tendons of six men who refrained from rigorous physical activities prior to the experiment were loaded cyclically by 10 repeated isometric plantarflexion contractions at 80% of the moment generated during plantarflexion maximal voluntary contraction (MVC). In each contraction, the elongation of the gastrocnemius tendon at 80% of MVC and the residual tendon elongation after relaxation were obtained from the analysis of sonographs recorded during the test. The tendon elongation during activation and the residual tendon elongation after relaxation increased by ca. 5 mm from the first contraction to the tenth contraction, with no changes obtained after the fifth contraction. The behaviour of the tendon in the first five contractions indicates the presence of conditioning. It is therefore concluded that conditioning is a relevant property and not an artefact associated with in vitro testing. This has implications for joint kinematics and muscle excursion. PMID:12952631

Maganaris, Constantinos N

2003-01-01

101

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

PubMed Central

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

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

2014-01-01

102

Experimental and theoretical studies on composite steelconcrete box beams with external tendons  

Microsoft Academic Search

Composite steelconcrete box beams with and without external tendons were tested to their ultimate strength. The effects of external tendons on structural performance of composite steelconcrete beams were investigated in detail. Experimental results proved that, due to the action of external prestressing tendons, the ultimate strength of a composite steelconcrete box beam increased by 27.72%, the elastic limit of a

Nan Zhang; Chung C. Fu

2009-01-01

103

Synthetic collagen fascicles for the regeneration of tendon tissue.  

PubMed

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

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

2012-10-01

104

Median Nerve as Free Tendon Graft  

Microsoft Academic Search

Four patients are described, all of whom bad tendon injuries in which the median nerve was used as a free tendon graft. Three cases involved the repair of a flexor tendon injury, and one the repair of an extensor tendon. In all cases, reconstruction of the median nerve was performed with a free sural nerve graft. The difficulty was that

1987-01-01

105

Achilles Tendon Rupture  

PubMed Central

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

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

2013-01-01

106

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

NASA Astrophysics Data System (ADS)

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.

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

2012-08-01

107

Posterior Tibial Tendon Dysfunction (PTTD)  

MedlinePLUS

... ACFAS | Informacin en Espaol 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. ...

108

Overweight and obesity alters the cumulativetransverse strain in the Achilles tendon immediately following exercise.  

PubMed

This research evaluated the effect of obesity on the acute cumulative transverse strain of the Achilles tendon in response to exercise. Twenty healthy adult males were categorized into 'low normal-weight' (BMI <23kgm(-2)) and 'overweight' (BMI >27.5kgm(-2)) groups based on intermediate cut-off points recommended by the World Health Organization. Longitudinal sonograms of the right Achilles tendon were acquired immediately prior and following weight-bearing ankle exercises. Achilles tendon thickness was measured 20-mm proximal to the calcaneal insertion and transverse tendon strain was calculated as the natural log of the ratio of post- to pre-exercise tendon thickness. The Achilles tendon was thicker in the overweight group both prior to (t18=-2.91, P=0.009) and following (t18=-4.87, P<0.001) exercise. The acute transverse strain response of the Achilles tendon in the overweight group (-10.72.5%), however, was almost half that of the 'low normal-weight' (-19.57.4%) group (t18=-3.56, P=0.004). These findings suggest that obesity is associated with structural changes in tendon that impairs intra-tendinous fluid movement in response to load and provides new insights into the link between tendon pathology and overweight and obesity. PMID:23768275

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

2013-07-01

109

[Experimental study in vivo on implantation of autogenous tendon cells after combining culture with carbon fibers].  

PubMed

In order to investigate the possibility of repairing injuried tendon with living artificial tendon, after combining culture, subcultured autogenous tendon cells with carbon fibers were implanted into the calcaneous tendon of rabbits. In different stages, the synthesis of type I collagen and their relevant morphological changes were observed. The results showed as follows: after implantation, tendon cells continued proliferating. Four weeks after implantation, tendon cells were detached from the carbon fibers and proliferated and produced collagen among the carbon fibers. The collagen fibrils were linked with each other to formed a dense structure. In the linkage site, the collagen fibrils originated from the implants joined to that from the ruptured end of the tendon, which meaned that the implant was healed with the recipient tendon. Observed under scanning electronic microscope, the tendon cells were lined among the carbon fibers evenly and in order, the collagen fibrils joined each other and formed an network, the fibrils were lined parallel to the carbon fibers. Under transparent electron microscope, the nucleolus were clear and organelle were abundant. PMID:9867920

Zhang, Q; Yang, Z; Peng, W

1997-05-01

110

Coracoclavicular ligament reconstruction: biomechanical comparison of tendon graft repairs to a synthetic double bundle augmentation.  

PubMed

For currently presented anatomical coracoclavicular ligament repairs issues such as autologous tendon graft versus synthetic suture augmentation and the optimum fixation strategies for both types of reconstruction are not solved. The purpose of the study was to compare the biomechanical properties of different tendon graft repairs to the characteristics of a synthetic polyester augmentation. Four anatomical coracoclavicular ligament repairs were biomechanically tested: 5 mm coracoclavicular tendon loop with suture fixation, tendon loop with flip button fixation, tendon loop with interference screw fixation versus a double 1.0-mm polyester repair with flip button fixation. The biomechanical testing included cyclic superio-inferior loading and a subsequent load to failure protocol. The ultimate failure loads were significantly higher for the double polyester/flip button repair (927 N) compared to all tendon repair techniques (maximum 640 N). In contrast the stiffness level was higher for the tendon repairs compared to the polyester/flip button repair (68.7 N/mm) but strongly dependent on the fixation technique (interference screw 97.2 N/mm, flip button 84.9 N/mm, side to side suture 60.9 N/mm). A synthetic coracoclavicular augmentation using a polyester suture provides adequate structural properties compared to a tendon repair. Therefore the decision for a tendon graft should be made by the necessity of a biologic substrate rather than by the assumption of a biomechanical advantage. PMID:19225755

Wellmann, Mathias; Kempka, Jan P; Schanz, Steffen; Zantop, Thore; Waizy, Hazibullah; Raschke, Michael J; Petersen, Wolf

2009-05-01

111

Triceps tendon reconstruction using ipsilateral palmaris longus autograft in unrecognized chronic tears.  

PubMed

Injury to the distal triceps tendon is uncommon and can be difficult to diagnose, especially when a partial rupture or tear occurs. In situations where an incomplete disruption to the musculotendinous unit occurs, a palpable defect or clear functional loss may not be present. Advanced imaging techniques, such as magnetic resonance imaging or ultrasound, can be used to confirm the diagnosis and define the extent of injury. The treatment of a complete rupture of the distal triceps tendon is repair or reconstruction, whereas the management of a patient with a partial triceps rupture is related to the pain, functional deficit, and expectations of the patient. This article presents 2 patients with chronic, near complete disruptions of the distal triceps tendon. In both patients, surgical reconstruction of the injured tendon was accomplished using ipsilateral palmaris longus autograft. This technique allows the treating surgeon to harvest the graft from the ipsilateral upper extremity. The palmaris autograft is then used to reconstruct the injured portion of the triceps tendon using a Pulvertaft weave technique through the intact triceps tendon and osseous tunnels within the proximal ulna. This technique allows for easy surgical setup and harvest of autograft tendon and provides a structurally sound technique for a tension-free reconstruction of the injured tendon. It also permits early postoperative elbow range of motion, with active elbow extension allowed at 6 weeks. The authors have used this technique successfully in the treatment of chronic partial tears of the distal triceps tendon. PMID:23276343

Scolaro, John A; Blake, Matthew H; Huffman, G Russell

2013-01-01

112

Model-based segmentation of flexor tendons from magnetic resonance images of finger joints  

Microsoft Academic Search

Trigger finger is a common hand disease, causing swelling, painful popping and clicking in moving the affected finger joint. To better evaluate patients with trigger finger, segmentation of flexor tendons from magnetic resonance (MR) images of finger joints, which can offer detailed structural information of tendons to clinicians, is essential. This paper presents a novel model-based method with three stages

H. C. Chen; C. K. Chen; T. H. Yang; L. C. Kuo; I. M. Jou; F. C. Su; Y. N. Sun

2011-01-01

113

SERVICEABILITY OF CONCRETE BEAMS PRESTRESSED BY FmRE REINFORCED PLASTIC TENDONS  

E-print Network

SERVICEABILITY OF CONCRETE BEAMS PRESTRESSED BY FmRE REINFORCED PLASTIC TENDONS by AMR A: SERVICEABILITY OF CONCRETE BEAMS PRESTRESSED BY CARBON FIBRE REINFORCED PLASTIC TENDONS Submitted by: AMR A reinforced plastic, CFRP, as prestressing reinforcement for concrete structures, has increased rapidly

114

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

PubMed Central

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

Wood, Lauren K.; Arruda, Ellen M.

2011-01-01

115

Management of extensor tendon injuries.  

PubMed

Extensor tendon injuries are very common injuries, which inappropriately treated can cause severe lasting impairment for the patient. Assessment and management of flexor tendon injuries has been widely reviewed, unlike extensor injuries. It is clear from the literature that extensor tendon repair should be undertaken immediately but the exact approach depends on the extensor zone. Zone I injuries otherwise known as mallet injuries are often closed and treated with immobilisaton and conservative management where possible. Zone II injuries are again conservatively managed with splinting. Closed Zone III or 'boutonniere' injuries are managed conservatively unless there is evidence of displaced avulsion fractures at the base of the middle phalanx, axial and lateral instability of the PIPJ associated with loss of active or passive extension of the joint or failed non-operative treatment. Open zone III injuries are often treated surgically unless splinting enable the tendons to come together. Zone V injuries, are human bites until proven otherwise requires primary tendon repair after irrigation. Zone VI injuries are close to the thin paratendon and thin subcutaneous tissue which strong core type sutures and then splinting should be placed in extension for 4-6 weeks. Complete lacerations to zone IV and VII involve surgical primary repair followed by 6 weeks of splinting in extension. Zone VIII require multiple figure of eight sutures to repair the muscle bellies and static immobilisation of the wrist in 45 degrees of extension. To date there is little literature documenting the quality of repairing extensor tendon injuries however loss of flexion due to extensor tendon shortening, loss of flexion and extension resulting from adhesions and weakened grip can occur after surgery. This review aims to provide a systematic examination method for assessing extensor injuries, presentation and management of all type of extensor tendon injuries as well as guidance on mobilisation pre and post surgery. PMID:22431949

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

2012-01-01

116

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

PubMed Central

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 45days. 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

2014-01-01

117

Improved Achilles tendon healing by early mechanical loading in a rabbit model  

PubMed Central

Objective: To investigate the structure and the attachment strength of a healing tendon-bone interface and the role of mechanical loading in tendon healing. Methods: Sixty rabbits underwent unilateral detachment and repair of the Achilles tendon. Thirty animals were immobilized (Group A), and the others wereallowed loadingimmediately postoperatively (Group B). Animals were sacrificed at 4 weeks and evaluated for histological and biomechanical testing. Statistical analysis was performed with an independent t test with significance set at P = 0.05. Results: The ultimate stress was greater in group B (4.598 1.321 N/mm2) compared with the control group (3.388 0.994 N/mm2) (P < 0.05). Similarly, a more organized tendon-to-bone interface with a larger area of chondrocytes was found in group B (P < 0.05). Conclusion: Mechanical loading improves the structure and the attachment strength of the healing tendon-to-bone interface. PMID:25785105

Wang, Jihong; Jiang, Dianming; Wen, Shuzheng; Jing, Shangfei; Fan, Dongsheng; Hao, Zengtao; Han, Chaoqian

2015-01-01

118

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

PubMed Central

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

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

2015-01-01

119

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

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

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

2014-01-01

120

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

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

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

2014-10-01

121

A New Method for Modeling Spatial Prestressing Tendons  

NASA Astrophysics Data System (ADS)

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.

Li, Yi; Wang, Yuqian; Liu, Gao

2010-05-01

122

Staged tendon grafts and soft tissue coverage  

PubMed Central

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

Elliot, David

2011-01-01

123

Achilles tendon reflex measuring system  

NASA Astrophysics Data System (ADS)

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.

Szebeszczyk, Janina; Straszecka, Joanna

1995-06-01

124

Magnetic resonance imaging of the elbow. Part II: Abnormalities of the ligaments, tendons, and nerves.  

PubMed

Part II of this comprehensive review on magnetic resonance imaging of the elbow discusses the role of magnetic resonance imaging in evaluating patients with abnormalities of the ligaments, tendons, and nerves of the elbow. Magnetic resonance imaging can yield high-quality multiplanar images which are useful in evaluating the soft tissue structures of the elbow. Magnetic resonance imaging can detect tears of the ulnar collateral ligament and lateral collateral ligament of the elbow with high sensitivity and specificity. Magnetic resonance imaging can determine the extent of tendon pathology in patients with medial epicondylitis and lateral epicondylitis. Magnetic resonance imaging can detect tears of the biceps tendon and triceps tendon and can distinguishing between partial and complete tendon rupture. Magnetic resonance imaging is also helpful in evaluating patients with nerve disorders at the elbow. PMID:15480640

Kijowski, Richard; Tuite, Michael; Sanford, Matthew

2005-01-01

125

Investigation of 2D and 3D electrospun scaffolds intended for tendon repair.  

PubMed

Two-dimensional (2D) electrospun fibre mats have been investigated as fibrous sheets intended as biomaterials scaffolds for tissue repair. It is recognised that tissues are three-dimensional (3D) structures and that optimisation of the fabrication process should include both 2D and 3D scaffolds. Understanding the relative merits of the architecture of 2D and 3D scaffolds for tendon repair is required. This study investigated three different electrospun scaffolds based on poly(?-caprolactone) fibres intended for repair of injured tendons, referred to as; 2D random sheet, 2D aligned sheet and 3D bundles. 2D aligned fibres and 3D bundles mimicked the parallel arrangement of collagen fibres in natural tendon and 3D bundles further replicated the tertiary layer of a tendon's hierarchical configuration. 3D bundles demonstrated greatest tensile properties, being significantly stronger and stiffer than 2D aligned and 2D random fibres. All scaffolds supported adhesion and proliferation of tendon fibroblasts. Furthermore, 2D aligned sheets and 3D bundles allowed guidance of the cells into a parallel, longitudinal arrangement, which is similar to tendon cells in the native tissue. With their superior physical properties and ability to better replicate tendon tissue, the 3D electrospun scaffolds warrant greater investigation as synthetic grafts in tendon repair. PMID:23504088

Bosworth, L A; Alam, N; Wong, J K; Downes, S

2013-06-01

126

Stochastic interdigitation as a toughening mechanism at the interface between tendon and bone.  

PubMed

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

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

2015-01-20

127

Presence of lymphatics in a rat tendon lesion model.  

PubMed

Tendons lack sufficient blood supply and represent a bradytroph tissue with prolonged healing time under pathological conditions. While the role of lymphatics in wound/defect healing in tissues with regular blood supply is well investigated, its involvement in tendon defects is not clear. We here try to identify the role of the lymphatic system in a tendon lesion model with morphological methods. A rat Achilles tendon lesion model (n=5) was created via surgical intervention. Two weeks after surgery, animals were killed and lesioned site removed and prepared for polarization microscopy (picrosirius red) and immunohistochemistry using the lymphatic markers PROX1, VEGFR3, CCL21, LYVE-1, PDPN, and the vascular marker CD31. Additionally, DAPI was applied. Untreated tendons served as controls, confocal laser-scanning microscopy was used for documentation. At the lesion site, polarization microscopy revealed a structural reintegration while immunohistochemistry detected band-like profiles immunoreactive for PDPN, VEGFR3, CCL21, LYVE1, and CD31, surrounding DAPI-positive nuclei. PROX1-positive nuclei were detected within the lesion forming lines and opposed to each other. These PROX1-positive nuclei were surrounded by LYVE-1- or VEGFR3-positive surfaces. Few CD31-positve profiles contained PROX1-positive nuclei, while the majority of CD31-positive profiles lacked PROX1-positive nuclei. VEGFR3-, PDPN-, and LYVE-1-positive profiles were numerous within the lesion site, but absent in control tissue. Within 2weeks, a structural rearrangement takes place in this lesion model, with dense lymphatic supply. The role of lymphatics in tendon wound healing is unclear, and proposed model represents a good possibility to study healing dynamics and lymphangiogenesis in a tissue almost completely lacking lymphatics in physiological conditions. PMID:25371325

Tempfer, Herbert; Kaser-Eichberger, Alexandra; Korntner, Stefanie; Lehner, Christine; Kunkel, Nadja; Traweger, Andreas; Trost, Andrea; Strohmaier, Clemens; Bogner, Barbara; Runge, Christian; Bruckner, Daniela; Krefft, Karolina; Heindl, Ludwig M; Reitsamer, Herbert A; Schrdl, Falk

2015-04-01

128

Developmental regulation of somite derivatives: muscle, cartilage and tendon  

Microsoft Academic Search

Recent research has broadened significantly our understanding of how the somite, a specialized mesodermal structure found in vertebrate embryos, gives rise to the cartilage, muscle and tendon cell lineages. The specification of somite derivatives involves the action of patterning signals secreted from adjacent tissue combined with the activation, in particular somitic compartments, of genes promoting cell lineage specification.

Ava E Brent; Clifford J Tabin

2002-01-01

129

Flexor tendon healing within the tendon sheath using bioabsorbable poly-L/D-lactide 96/4 suture. A histological in vivo study with rabbits.  

PubMed

The bioabsorbable poly-L/D-lactide (PLDLA) 96/4 suture has good biomechanical and knot properties, and sufficient tensile strength half-life for flexor tendon repair. In the present study, the biocompatibility of PLDLA suture was compared with that of coated braided polyester suture in the rabbit flexor digitorum profundus tendon repaired within the tendon sheath. Postoperative unrestricted active mobilization was allowed. The tendons were studied histologically after 1-, 3-, 6-, 12-, 26-, and 52-week follow-ups. No differences were found in the biocompatibility between the suture materials, with only scattered multinuclear giant cells near the sutures in both groups from 6 weeks onwards. At 52 weeks, most of the PLDLA material was absorbed and the histological structure of the tendon appeared normal, whereas in the polyester repairs the suture knots filled the repair site, causing bulking of the tendon surface, and the collagen alignment appeared disoriented. The results suggest that the PLDLA 96/4 is a suitable suture material for flexor tendon repair. PMID:24477875

Viinikainen, Anna; Gransson, Harry; Taskinen, Hanna-Stina; Rytt, Matias; Kellomki, Minna; Trml, Pertti; Rokkanen, Pentti

2014-05-01

130

[Tendinopathy of the gluteus medius tendon].  

PubMed

Tendinopathy of the gluteus medius tendon is the main cause of great trochanter pain syndrom. Recent clinical, ultrasonographic and MRI study, allow to distinguish anterior lesions which concern the lateral part of the gluteus medius tendon, almost always associated with tendinopathy of the gluteus minimus tendon, from tendinopathy of the main tendon of the gluteus medius. Tears of the main tendon of the gluteus medius are the serious disabling consequence of that pathology and must be avoid by early medical and functional treatment with very moderate use of intrabursal corticosteroid injections. In few cases without improvement after medical treatment, surgery is indicated and includes bursectomy of the trochanteric bursa and tendinoplasty. PMID:19462863

Bard, Herv

2009-04-20

131

Bioreactor Design for Tendon/Ligament Engineering  

PubMed Central

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

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

2013-01-01

132

Transcription factor EGR1 directs tendon differentiation and promotes tendon repair  

PubMed Central

Tendon formation and repair rely on specific combinations of transcription factors, growth factors, and mechanical parameters that regulate the production and spatial organization of type I collagen. Here, we investigated the function of the zinc finger transcription factor EGR1 in tendon formation, healing, and repair using rodent animal models and mesenchymal stem cells (MSCs). Adult tendons of Egr1/ mice displayed a deficiency in the expression of tendon genes, including Scx, Col1a1, and Col1a2, and were mechanically weaker compared with their WT littermates. EGR1 was recruited to the Col1a1 and Col2a1 promoters in postnatal mouse tendons in vivo. Egr1 was required for the normal gene response following tendon injury in a mouse model of Achilles tendon healing. Forced Egr1 expression programmed MSCs toward the tendon lineage and promoted the formation of in vitroengineered tendons from MSCs. The application of EGR1-producing MSCs increased the formation of tendon-like tissues in a rat model of Achilles tendon injury. We provide evidence that the ability of EGR1 to promote tendon differentiation is partially mediated by TGF-?2. This study demonstrates EGR1 involvement in adult tendon formation, healing, and repair and identifies Egr1 as a putative target in tendon repair strategies. PMID:23863709

Guerquin, Marie-Justine; Charvet, Benjamin; Nourissat, Geoffroy; Havis, Emmanuelle; Ronsin, Olivier; Bonnin, Marie-Ange; Ruggiu, Mathilde; Olivera-Martinez, Isabel; Robert, Nicolas; Lu, Yinhui; Kadler, Karl E.; Baumberger, Tristan; Doursounian, Levon; Berenbaum, Francis; Duprez, Delphine

2013-01-01

133

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

NASA Astrophysics Data System (ADS)

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.

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

2011-03-01

134

Ultrasound elasticity imaging of human posterior tibial tendon  

NASA Astrophysics Data System (ADS)

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.

Gao, Liang

135

Analysis of collagen organization in mouse achilles tendon using high-frequency ultrasound imaging.  

PubMed

Achilles tendon ruptures are traumatic injuries, and techniques for assessing repair outcomes rely on patient-based measures of pain and function, which do not directly assess tendon healing. Consequently, there is a need for a quantitative, in vivo measure of tendon properties. Therefore, the purpose of this study was to validate ultrasound imaging for evaluating collagen organization in tendons. In this study, we compared our novel, high-frequency ultrasound (HFUS) imaging and analysis method to a standard measure of collagen organization, crossed polarizer (CP) imaging. Eighteen mouse Achilles tendons were harvested and placed into a testing fixture where HFUS and CP imaging could be performed simultaneously in a controlled loading environment. Two experiments were conducted: (1) effect of loading on collagen alignment and (2) effect of an excisional injury on collagen alignment. As expected, it was found that both the HFUS and CP methods could reliably detect an increase in alignment with increasing load, as well as a decrease in alignment with injury. This HFUS method demonstrates that structural measures of collagen organization in tendon can be determined through ultrasound imaging. This experiment also provides a mechanistic evaluation of tissue structure that could potentially be used to develop a targeted approach to aid in rehabilitation or monitor return to activity after tendon injury. PMID:24356929

Riggin, Corinne N; Sarver, Joseph J; Freedman, Benjamin R; Thomas, Stephen J; Soslowsky, Louis J

2014-02-01

136

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

NASA Astrophysics Data System (ADS)

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

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

2001-10-01

137

An Improved Force Feedback Control Algorithm for Active Tendons  

PubMed Central

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

Guo, Tieneng; Liu, Zhifeng; Cai, Ligang

2012-01-01

138

Two-Staged Reconstruction of the Flexor Pollicis Longus Tendon  

Microsoft Academic Search

The purpose of this study was to evaluate the results of two-stage reconstruction of the flexor pollicis longus (FPL) tendon. Sixteen patients who underwent reconstructive surgery of the FPL tendon were assessed retrospectively. Eight weeks after implantation of a silastic spacer, a tendon graft was used for reconstruction (thirteen palmaris longus tendons, two plantaris tendons, one half of the flexor

F. UNGLAUB; C. BULTMANN; A. REITER; P. HAHN

2006-01-01

139

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

PubMed

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

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

2015-04-13

140

Prestressed concrete using KEVLAR reinforced tendons  

SciTech Connect

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.

Dolan, C.W.

1989-01-01

141

Fetal and adult fibroblasts display intrinsic differences in tendon tissue engineering and regeneration  

PubMed Central

Injured adult tendons do not exhibit optimal healing through a regenerative process, whereas fetal tendons can heal in a regenerative fashion without scar formation. Hence, we compared FFs (mouse fetal fibroblasts) and AFs (mouse adult fibroblasts) as seed cells for the fabrication of scaffold-free engineered tendons. Our results demonstrated that FFs had more potential for tendon tissue engineering, as shown by higher levels of tendon-related gene expression. In the in situ AT injury model, the FFs group also demonstrated much better structural and functional properties after healing, with higher levels of collagen deposition and better microstructure repair. Moreover, fetal fibroblasts could increase the recruitment of fibroblast-like cells and reduce the infiltration of inflammatory cells to the injury site during the regeneration process. Our results suggest that the underlying mechanisms of better regeneration with FFs should be elucidated and be used to enhance adult tendon healing. This may assist in the development of future strategies to treat tendon injuries. PMID:24992450

Tang, Qiao-Mei; Chen, Jia Lin; Shen, Wei Liang; Yin, Zi; Liu, Huan Huan; Fang, Zhi; Heng, Boon Chin; Ouyang, Hong Wei; Chen, Xiao

2014-01-01

142

Mineralization-related modifications in the calcifying tendons of turkey (Meleagris gallopavo).  

PubMed

The tendons of some birds undergo a physiological process of gradual mineralization, usually limited to the central portion of the tendon and resulting in an increase of the elastic modulus and the ultimate strength. The present study was carried out by light microscopy and scanning electron microscopy and was focused on the structural and ultrastructural modifications occurring in this tissue during biomineralization. In comparison with most other tendons, turkey tendons appeared to be more finely subdivided into thinner fascicles and to contain a greater amount of cell-rich endotenon tissue. The most obvious finding, however, was the complete disappearance of the crimps in the calcified portions of the tendon, while they were present with the usual morphology in the non-mineralized portion. The electron microscopy revealed in the mineralized tendon traces of pre-existing crimps, locked in the straightened-out position by the infiltrating mineral phase. This latter was composed of two different types of fine particles, respectively, growing inside and around the collagen fibrils and appearing as tightly packed platelets or as larger, flat platelets regularly arranged in phase with the D-period of collagen. The perifibrillar mineral could play a critical role in the mechanical coupling of adjoining fascicles and in the transmission of tensile loads along the tendon itself. PMID:25698547

Raspanti, Mario; Reguzzoni, Marcella; Protasoni, Marina; Congiu, Terenzio

2015-04-01

143

Strain distribution due to propagation of tears in the anterior supraspinatus tendon.  

PubMed

Rotator cuff tears are a significant clinical problem. Tears in the anterior supraspinatus might behave differently compared to central tears due to differences in regional structural properties. The objective of this study was to determine strain distributions for anterior supraspinatus tendon tears and the relationship to tear propagation during cyclic loading. It was hypothesized that highest maximum principal strain would be posterior to the tear, and tears would propagate in the direction of the maximum principal strain. Eight human cadaveric supraspinatus tendons with surgically created small tears in the anterior third were tested with increasing levels of cyclic loads. The position of strain markers was recorded on the bursal surface of the tendon to calculate strain. Tendons reached a 2?cm critical tendon retraction at 580??181?N. Largest strains were found medial and posterior to the tear (26.1??9.4%). In five tendons, the strain direction for the initial (114??28) and final loading sets (86??20) indicated the strain direction shifted from an anterior to posterior orientation (p?tendon during activities of daily living. PMID:24985532

Miller, R Matthew; Fujimaki, Yoshimasa; Araki, Daisuke; Musahl, Volker; Debski, Richard E

2014-10-01

144

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

Microsoft Academic Search

BACKGROUND: The purpose of the study is to retrospectively review the clinical outcome of our study population of middle-aged RA patients who had suffered extensor-tendon rupture. We reported the outcome of autogenous palmaris tendon grafting of multiple extensor tendons at wrist level in 14 middle-aged rheumatoid patients. METHODS: Between Feb. 2000 to Feb. 2004, thirty-six ruptured wrist level extensor tendons

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

2008-01-01

145

Treatment of unfavourable results of flexor tendon surgery: Skin deficiencies  

PubMed Central

We recently reported a small study at the Federation of European Societies for Surgery of the hand, which was entitled What is secondary flexor tendon surgery? This study concluded that secondary flexor tendon surgery was a generic name encompassing a multitude of pathologies. Between 10% and 15% of cases exhibited pathology of the skin and subcutaneous fat and required flap reconstruction of these tissues. Skin replacement may be used prophylactically at primary surgery or become necessary at secondary surgery after release of scar contractures, to achieve cover of vital structures. The long-term problem of skin deficiency relating to flexor tendon function is one of loss of extension from longitudinal scar shortening of the integument, even if the flexor tendons are primarily concerned with bending the digits, not straightening them. This loss of extension can only be tolerated in a hand to a certain degree without significant loss of function. This paper is largely an analysis of the flaps available and suitable for different degrees of skin deficiency and at different places along the course of the flexor system. It attempts to dispel the idea that any flap will do provided the flexors are adequately covered. PMID:24501469

Elliot, David; Giesen, Thomas

2013-01-01

146

Management of chronic tendon injuries.  

PubMed

Chronic tendon injuries present unique management challenges. The assumption that these injuries result from ongoing inflammation has caused physicians to rely on treatments demonstrated to be ineffective in the long term. Nonsteroidal anti-inflammatory drugs should be limited in the treatment of these injuries. Corticosteroid injections should be considered for temporizing pain relief only for rotator cuff tendinopathy. For chronic Achilles tendinopathy (symptoms lasting longer than six weeks), an intense eccentric strengthening program of the gastrocnemius/ soleus complex improved pain and function between 60 and 90 percent in randomized trials. Evidence also supports eccentric exercise as a first-line option for chronic patellar tendon injuries. Other modalities such as prolotherapy, topical nitroglycerin, iontophoresis, phonophoresis, therapeutic ultrasound, extracorporeal shock wave therapy, and low-level laser therapy have less evidence of effectiveness but are reasonable second-line alternatives to surgery for patients who have persistent pain despite appropriate rehabilitative exercise. PMID:23547590

Childress, Marc A; Beutler, Anthony

2013-04-01

147

A Somitic Compartment of Tendon Progenitors  

Microsoft Academic Search

We demonstrate that the tendons associated with the axial skeleton derive from a heretofore unappreciated, fourth compartment of the somites. Scleraxis (Scx), a bHLH transcription factor, marks this somitic tendon progenitor population at its inception, and is continuously expressed through differentiation into the mature tendons. Two earlier-formed somitic compartments, the sclerotome and myotome, interact to establish this fourth Scx-positive compartment.

Ava E Brent; Ronen Schweitzer; Clifford J Tabin

2003-01-01

148

Tendon transfers for the drop foot.  

PubMed

The paralytic drop foot represents a challenging problem for even the most experienced orthopedic surgeon. Careful patient selection, thorough preoperative examination and planning, and application of tendon transfer biomechanical and physiologic principles outlined in this article can lead to successful results, either through a posterior tibialis tendon transfer, Bridle transfer, or variations on these procedures. Achilles lengthening or gastrocnemius recession may also be needed at the time of tendon transfer. PMID:24548510

Schweitzer, Karl M; Jones, Carroll P

2014-03-01

149

Free tendon interposition grafting for the repair of ruptured extensor tendons in the rheumatoid hand  

Microsoft Academic Search

Sixteen ruptured extensor tendons were repaired in seven rheumatoid hands using autogenous palmaris longus tendon as a free interposition graft. The patients were reviewed at an average of 17 months (range, 545) after repair. Subjectively all patients were satisfied with the clinical results, and achieved a return to their level of ability before tendon rupture. A biomechanical model suggests that

J. Mountney; C. M. Blundell; P. McArthur

1998-01-01

150

Quadriceps and patellar tendon ruptures.  

PubMed

The diagnosis of quadriceps and patellar tendon ruptures requires a high index of suspicion and thorough history-taking to assess for medical comorbidities that may predispose patients to tendon degeneration. Radiographic assessment with plain films supplemented by ultrasound and magnetic resonance imaging when the work-up is equivocal further aids diagnosis; however, advanced imaging is often unnecessary in patients with functional extensor mechanism deficits. Acute repair is preferred, and transpatellar bone tunnels serve as the primary form of fixation when the tendon rupture occurs at the patellar insertion, with or without augmentation depending on surgeon preference. Chronic tears and disruptions following total knee arthroplasty are special cases requiring reconstructions with allograft, synthetic mesh, or autograft. Rehabilitation protocols generally allow immediate weight-bearing with the knee locked in extension and crutch support. Limited arc motion is started early with active flexion and passive extension and then advanced progressively, followed by full active range of motion and strengthening. Complications are few but include quadriceps atrophy, knee stiffness, and rerupture. Outcomes are excellent if repair is done acutely, with poorer outcomes associated with delayed repair. PMID:23955186

Lee, Dennis; Stinner, Daniel; Mir, Hassan

2013-10-01

151

Intra-articular changes precede extra-articular changes in the biceps tendon following rotator cuff tears in a rat model  

PubMed Central

Background Biceps tendon pathology is common with rotator cuff tears. The mechanisms for biceps changes, and therefore its optimal treatment, are unknown. Our objective was to determine the effect of rotator cuff tears on regional biceps tendon pathology. We hypothesized that histological and compositional changes would appear before organizational changes, both would appear before mechanical changes, and changes would begin at the tendons insertion site. Methods Sixty-five Sprague-Dawley rats received either detachment of supraspinatus and infraspinatus tendons or sham surgery. Rats were sacrificed at 1, 4 or 8 weeks for regional measurements of histological, compositional, organizational (1, 4 and 8 weeks) or mechanical properties (4 and 8 weeks only). Results One week following tendon detachments, decreased organization and more rounded cell shape were found in the intra-articular space of the biceps tendon. Aggrecan expression was increased along the entire length of the tendon while all other compositional changes were at the tendons proximal insertion into bone only. With time, this disorganization and more rounded cell shape extended the length of the tendon. Organizational and cell shape changes also preceded detrimental mechanical changes, as decreased modulus in the intra-articular space was found after 8 weeks. Conclusions Results support a degenerative component to pathology in the biceps tendon. Additionally, changes resembling a tendon exposed to compressive loading occurring first in the intra-articular space indicate that the biceps tendon plays an increased role as a load bearing structure against the humeral head in the presence of rotator cuff tears. PMID:21816629

Peltz, Cathryn D.; Hsu, Jason E.; Zgonis, Miltiadis H.; Trasolini, Nicholas A.; Glaser, David L.; Soslowsky, Louis J.

2011-01-01

152

Tendon Based Full Size Biped Humanoid Robot Walking Platform Design  

NASA Astrophysics Data System (ADS)

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.

Kuo, Chung-Hsien; Chiou, Kuo-Wei

153

Controlled delivery of mesenchymal stem cells and growth factors using a nanofiber scaffold for tendon repair  

PubMed Central

Outcomes after tendon repair are often unsatisfactory, despite improvements in surgical techniques and rehabilitation methods. Recent studies aimed at enhancing repair have targeted the paucicellular nature of tendon for enhancing repair; however, most approaches for delivering growth factors and cells have not been designed for dense connective tissues such as tendon. Therefore, we developed a scaffold capable of delivering growth factors and cells in a surgically manageable form for tendon repair. The growth factor PDGF-BB along with adipose-derived mesenchymal stem cells (ASCs) was incorporated into a heparin/fibrin-based delivery system (HBDS). This hydrogel was then layered with an electrospun nanofiber poly-lactic-co-glycolic acid (PLGA) backbone. The HBDS allowed for the concurrent delivery of PDGF-BB and ASCs in a controlled manner, while the PLGA backbone provided structural integrity for surgical handling and tendon implantation. In vitro studies verified that the cells remained viable, and that sustained growth factor release was achieved. In vivo studies in a large animal tendon model verified that the approach was clinically relevant, and that the cells remained viable in the tendon repair environment. Only a mild immunoresponse was seen at dissection, histologically, and at the mRNA level; fluorescently-labeled ASCs and the scaffold were found at the repair site 9 days postoperatively; and increased total DNA was observed in ASC-treated tendons. The novel layered scaffold has the potential for improving tendon healing due to its ability to deliver both cells and growth factors simultaneously in a surgically convenient manner. PMID:23416576

Manning, CN; Schwartz, AG; Liu, W; Xie, J; Havlioglu, N; Sakiyama-Elbert, SE; Silva, MJ; Xia, Y; Gelberman, RH; Thomopoulos, S

2013-01-01

154

Cushing, acromegaly, GH deficiency and tendons  

PubMed Central

Summary Cushings syndrome, induced by an endogenous or exogenous cortisol excess, and acromegaly, the clinical syndrome caused by growth hormone (GH) excess in adulthood, as well as the disease induced by GH deficiency (GHD), represent perfect models for the evaluation of the effects induced by chronic exposure in vivo, respectively, to cortisol and GH/IGF-1 excess or deficiency on the complex structure of the tendons as well as on the related post-traumatic repair mechanism. Although the literature is still scant, here in main scientific evidence on this topic is summarized in order to provide suggestions about the management of the above mentioned illnesses, to translate such information in the field of sports medicine and/or traumatology, and to increase and to disseminate knowledge on this misunderstood theme. PMID:25489551

Galdiero, Mariano; Auriemma, Renata S.; Pivonello, Rosario; Colao, Annamaria

2014-01-01

155

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

SciTech Connect

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.

Tabatabai, H.

1995-12-01

156

Tissue Engineering Strategies for the Tendon/ligament-to-bone insertion  

PubMed Central

Injuries to connective tissues are painful and disabling and result in costly medical expenses. These injuries often require re-attachment of an unmineralized connective tissue to bone. The uninjured tendon/ligament-to-bone insertion (enthesis) is a functionally graded material that exhibits a gradual transition from soft tissue (i.e., tendon or ligament) to hard tissue (i.e., mineralized bone) through a fibrocartilaginous transition region. This transition is believed to facilitate force transmission between the two dissimilar tissues by ameliorating potentially damaging interfacial stress concentrations. The transition region is impaired or lost upon tendon/ligament injury and is not regenerated following surgical repair or natural healing, exposing the tissue to risk of re-injury. The need to regenerate a robust tendon-to-bone insertion has led a number of tissue engineering repair strategies. This review treats the tendon-to-bone insertion site as a tissue structure whose primary role is mechanical and discusses current and emerging strategies for engineering the tendon/ligament-to-bone insertion in this context. The focus lies on strategies for producing mechanical structures that can guide and subsequently sustain a graded tissue structure and the associated cell populations. PMID:22185608

Smith, Lester; Xia, Younan; Galatz, Leesa M.; Genin, Guy M.; Thomopoulos, Stavros

2012-01-01

157

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

NASA Astrophysics Data System (ADS)

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.

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

2008-02-01

158

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

PubMed Central

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

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

2014-01-01

159

Extensor tendon injury due to repetitive wrist dorsiflexion: morphological study of extensor retinaculum and extensor tendon.  

PubMed

Most etiological studies of extensor tendon injury were based on the normal anatomy of extensor tendon and extensor retinaculum of the wrist. Further understanding of the morphological changes of the extensor tendon and extensor retinaculum during wrist dorsiflexion might contribute to improved and more accurate understanding of the etiology. The morphology of the extensor tendon of the mid-finger and the fourth compartment of the wrist extensor retinaculum was studied by sonography, and the anatomy was studied in 15 extremities from 11 young male cadavers. Compared with anatomical images, ultrasonography provides similar morphological observations of the extensor retinaculum of the wrist and extensor tendon. Ultrasonography findings revealed that as the dorsiflexion angle changed, the extensor retinaculum of the wrist formed different shaped trochleas. The trochlea guides the rotation of the extensor tendon at the wrist, but it does not form a sharp corner with the extensor tendon; thus, the extensor tendon is not compressed. As the dorsiflexion angle increased from 0 to 60, the length of the trochlea gradually decreases. The shortening of the trochlea length will lead to a smaller frictional contact area between the extensor tendon and the extensor retinaculum. Consequently, the friction is centralized. During wrist dorsiflexion, the extensor retinaculum provides a trochlea for the extensor tendon. Extensor tendon injury of repetitive wrist dorsiflexion might be caused by centralized friction at the small contact area. PMID:24902538

Zhou, Chang-long; Wang, Xin-tao; Chi, Zhi-yong; Yan, Jing-long

2014-11-01

160

Effect of triggering and entrapment on tendon gliding properties following digital flexor tendon laceration: in vitro study on turkey tendon.  

PubMed

The optimal management of partial flexor tendon laceration is controversial and remains a clinical challenge. Abnormal tendon gliding (triggering and entrapment) was assessed at the A2 pulley in 40 turkey tendons in three groups: intact, partially divided (palmar or lateral), and trimmed. Testing was of gliding resistance and friction coefficient at 30 and 70 of flexion, loaded with 2 and 4 N. We observed for triggering and entrapment. The changes in gliding properties were compared and analysed using Wilcoxon matched pair testing. A significant difference was found in the change in gliding properties of intact to lacerated and lacerated to trimmed tendons and between tendons that glided normally compared with those exhibiting triggering or entrapment. This suggests that palmar and lateral lacerations which, through clinical examination and visualization, are found to glide normally should be treated with early mobilization. However, partial lacerations that exhibit triggering or entrapment should be trimmed. PMID:23735810

Kennedy, J A; Dias, J J

2014-09-01

161

Calcific tendonitis of the tibialis posterior tendon at the navicular attachment  

PubMed Central

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

Harries, Luke; Kempson, Susan; Watura, Roland

2011-01-01

162

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

PubMed Central

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

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

163

Measuring Regional Changes in Damaged Tendon  

NASA Astrophysics Data System (ADS)

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.

Frisch, Catherine Kayt Vincent

164

Augmentation of tendon-to-bone healing.  

PubMed

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

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

165

Rehabilitation Following Zone II Flexor Tendon Repairs.  

PubMed

Ongoing clinical and basic research has improved understanding of flexor tendon mechanics and physiology for surgical repair and rehabilitation after a zone II flexor tendon repair. Yet, the ideal surgical repair technique that includes sufficient strength to allow safe immediate active motion of the finger, without excessive repair stiffness, bulk or rough surfaces resulting in excessive resistance to flexion, does not exist. After optimizing the repair, the surgeon and therapist team must select a rehabilitation plan that protects the repair but helps to maintain tendon gliding. There are 3 types of rehabilitation programs for flexor tendon repairs: delayed mobilization, early passive mobilization, or an early active mobilization. No guideline for rehabilitation should be followed exactly. Many factors influence therapy decisions, including repair technique, associated tendon healing, passive versus active range of motion, edema, and tendon adhesions. These factors can assist in guiding rehabilitation progression and promote functional range of motion, safely mobilize the repaired tendon(s) and prevent gapping, rupture, and adhesions. PMID:25700105

Kannas, Stephanie; Jeardeau, Teresa A; Bishop, Allen T

2015-03-01

166

Morphology of human palmaris longus tendon  

Microsoft Academic Search

A systematic morphological investigation of human palmaris longus tendons by polarisation microscopy and low angle x-ray diffraction is reported. It is shown that contrary to some previously reported observations, and in common with other tension bearing soft collagenous tissues, the fibres in this tendon are crimped. A new method of preparation of the tissue enabling one to see directly the

S P Nicholls; L J Gathercole; J S Shah

1984-01-01

167

THE EXTENDED PALMARIS LONGUS TENDON GRAFT  

Microsoft Academic Search

A technique is described of increasing the length of a palmaris longus tendon graft by including palmar aponeurosis. The additional 5 cm is often useful in treating high flexor tendon ruptures, especially at the wrist level, without the need for an additional incision.

A. R. TOLAT; J. K. STANLEY

1993-01-01

168

HARVEST OF PALMARIS LONGUS TENDON: TECHNIQUE  

Microsoft Academic Search

We present a modification of Bunnell's technique for harvest of the palmaris longus tendon. Using a 0.5 cm distal incision and a proximal stab incision the tendon is harvested with minimal scarring and, in our experience of over 30 cases, no morbidity.

W. R. SAEED; S. P. KAY

1993-01-01

169

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

PubMed

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

Vieira, M H C; Oliveira, R J; Ea, 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

170

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

PubMed

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

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

2013-01-01

171

Ultrasonic evaluation of flood gate tendons  

NASA Astrophysics Data System (ADS)

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.

Thomas, Graham H.; Brown, Albert E.

1998-03-01

172

Ultrasonic evaluation of flood gate tendons  

SciTech Connect

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.

Thomas, G.; Brown, A.

1997-10-01

173

The pathogenesis of tendon microdamage in athletes: the horse as a natural model for basic cellular research.  

PubMed

The equine superficial digital flexor tendon (SDFT) is a frequently injured structure that is functionally and clinically equivalent to the human Achilles tendon (AT). Both act as critical energy-storage systems during high-speed locomotion and can accumulate exercise- and age-related microdamage that predisposes to rupture during normal activity. Significant advances in understanding of the biology and pathology of exercise-induced tendon injury have occurred through comparative studies of equine digital tendons with varying functions and injury susceptibilities. Due to the limitations of in-vivo work, determination of the mechanisms by which tendon cells contribute to and/or actively participate in the pathogenesis of microdamage requires detailed cell culture modelling. The phenotypes induced must ultimately be mapped back to the tendon tissue environment. The biology of tendon cells and their matrix, and the pathological changes occurring in the context of early injury in both horses and people are reviewed, with a particular focus on the use of various tendon cell and tissue culture systems to model these events. PMID:22789861

Patterson-Kane, J C; Becker, D L; Rich, T

2012-01-01

174

Preparation and characterization of decellularized tendon slices for tendon tissue engineering.  

PubMed

To develop a naturally derived tendon tissue engineering scaffold with the preservation of the native ultrastructure, tensile strength, and biochemical composition of the tendon extracellular matrix (ECM), decellularized tendon slices (DTSs) were prepared using repetitive freeze/thaw of the intact Achilles tendons, frozen section, and nuclease treatment. The DTSs were characterized in the native ultrastructure, mechanical properties, biochemical composition, and cytocompatibility. Histological examination and DNA quantification analysis confirmed that cells were completely removed from tendon tissue by repetitive freeze/thaw in combination with nuclease treatment 12 h. The intrinsic ultrastructure of tendon tissue was well preserved based on scanning electron microscopy examination. The tensile strength of the DTSs was retained 85.62% of native tendon slice. More than 93% of proteoglycans (fibromodulin, biglycan) and growth factors (TGF-?1, IGF-1, VEGF, and CTGF) inherent in tendon ECM were preserved in the DTSs according to ELISA analysis. Furthermore, the DTSs facilitated attachment and repopulation of NIH-3T3 fibroblasts in vitro. Overall, the DTSs are sheet scaffolds with a combination of elemental mechanical strength and tendon ECM bioactive factors that may have many potential applications in tendon tissue engineering. PMID:22378703

Ning, Liang-Ju; Zhang, Yi; Chen, Xiao-He; Luo, Jing-Cong; Li, Xiu-Qun; Yang, Zhi-Ming; Qin, Ting-Wu

2012-06-01

175

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

PubMed Central

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

Gulick, Dawn T.; Yoder, Heather N.

2002-01-01

176

Artificial tendons: biomechanical design properties for prosthetic lower limbs  

Microsoft Academic Search

This paper reports on the design of an artificial tendon intended for use in a powered, lower limb prosthesis. To specify performance requirements, the properties of mammalian weight bearing tendons are drawn from the literature and compared with a number of existing tendon models. Based on the data, a mathematical model of an energy storing tendon is proposed and used

Glenn K. Klute; Joseph M. Czerniecki; Blake Hannaford

2000-01-01

177

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

Microsoft Academic Search

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

S. Malvankar; W. S. Khan

178

Tendon rupture associated with simvastatin/ezetimibe therapy.  

PubMed

A case of spontaneous biceps tendon rupture in a physician during therapy with the combination of simvastatin and ezetimibe (Vytorin) is reported. Rechallenge produced tendinopathy in the contralateral biceps tendon that abated with drug discontinuation. Tendon rupture generally occurs in injured tendons. Physiological repair of an injured tendon requires degradation and remodeling of the extracellular matrix through matrix metalloproteinases (MMPs). Statins are known to inhibit MMPs. It was hypothesized that statins may increase the risk of tendon rupture by altering MMP activity. In conclusion, statins may increase the risk of tendon rupture by altering MMP activity. PMID:17599460

Pullatt, Raja C; Gadarla, Mamatha Reddy; Karas, Richard H; Alsheikh-Ali, Alawi A; Thompson, Paul D

2007-07-01

179

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

PubMed Central

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

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

2015-01-01

180

[Effects of Gravity on Attachment of Tendon to Bone  

NASA Technical Reports Server (NTRS)

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.

Johnson, Roger B.

1997-01-01

181

Osmotic pressure induced tensile forces in tendon collagen  

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

182

Osmotic pressure induced tensile forces in tendon collagen  

PubMed Central

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

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

2015-01-01

183

Palmaris profundus tendon prohibiting endoscopic carpal tunnel release: case report.  

PubMed

Palmaris profundus is an aberrant muscle of forearm and wrist anatomy. It has no discernible function, but its tendon has been implicated as a cause of carpal tunnel syndrome. Previously, all cases of palmaris profundus in the literature have been encountered during either open surgery or cadaveric dissection. We report a case of palmaris profundus encountered during attempted single-portal endoscopic carpal tunnel release, necessitating conversion to an open approach. There was a unique point of tendon insertion onto the undersurface of the transverse carpal ligament, more proximal than what has been previously described in the literature. There were other anomalies present as well, including a persistent median artery and bifid median nerve. Given the volar position of the structure, its proximal point of insertion, and its minimal bulk, we did not feel that this was the cause of our patient's carpal tunnel syndrome. PMID:22397841

McClelland, Walter B; Means, Kenneth R

2012-04-01

184

Structural and functional modulation of early healing of full-thickness superficial digital flexor tendon rupture in rabbits by repeated subcutaneous administration of exogenous human recombinant basic fibroblast growth factor.  

PubMed

The present study was designed to investigate the effects of basic fibroblast growth factor on the healing of the acute phase of complete superficial digital flexor tendon rupture in rabbits. A total of 40 skeletally mature female white New Zealand rabbits were randomly divided into 2 equal groups of injured treated and injured control. After tenotomy and surgical anastomosis, using a modified Kessler and running pattern, the injured legs were placed in casts for 14 days, and basic fibroblast growth factor was injected subcutaneously over the lesion on days 3, 7, and 10 after injury. The injured control rabbits received a normal saline injection in a similar protocol. The rabbits' weight, tendon diameter, clinical signs, radiographs, and ultrasound scans were evaluated weekly. The rabbits were killed 28 days after injury, and the tendons were evaluated at the macroscopic, histopathologic, and ultrastructural levels and for biomechanical and the percentage of dry weight analysis. Treatment significantly reduced the diameter and increased the echogenicity and dry weight content and enhanced the maturation rate of the tenoblasts, fibrillogenesis, collagen fibril diameter, fibrillar density, tensile strength, and stiffness and stress of the injured tendons. Treatment with basic fibroblast growth factor was effective in restoring the morphologic and biomechanical properties of the injured superficial digital flexor tendon and could be valuable in clinical trial studies. PMID:21683624

Moshiri, Ali; Oryan, Ahmad

2011-01-01

185

Estimation of the effective static moment arms of the tendons in the index finger extensor mechanism.  

PubMed

A novel technique to estimate the contribution of finger extensor tendons to joint moment generation was proposed. Effective static moment arms (ESMAs), which represent the net effects of the tendon force on joint moments in static finger postures, were estimated for the 4 degrees of freedom (DOFs) in the index finger. Specifically, the ESMAs for the five tendons contributing to the finger extensor apparatus were estimated by directly correlating the applied tendon force to the measured resultant joint moments in cadaveric hand specimens. Repeated measures analysis of variance revealed that the finger posture, specifically interphalangeal joint angles, had significant effects on the measured ESMA values in 7 out of 20 conditions (four DOFs for each of the five muscles). Extensor digitorum communis and extensor indicis proprius tendons were found to have greater MCP ESMA values when IP joints are flexed, whereas abduction ESMAs of all muscles except extensor digitorum profundus were mainly affected by MCP flexion. The ESMAs were generally smaller than the moment arms estimated in previous studies that employed kinematic measurement techniques. Tendon force distribution within the extensor hood and dissipation into adjacent structures are believed to contribute to the joint moment reductions, which result in smaller ESMA values. PMID:18387615

Lee, Sang Wook; Chen, Hua; Towles, Joseph D; Kamper, Derek G

2008-01-01

186

Managing the injured tendon: current concepts.  

PubMed

Despite advances in understanding of the mechanical aspects of tendon management with improved suture technique and early stress application with postoperative therapy, clinical results remain inconsistent after repair, especially within the synovial regions. Complementary research to enhance the intrinsic pathway of healing, suppress the extrinsic pathway of healing, and manipulate frictional resistance to tendon gliding is now the focus of current basic science research on tendons. In the future, application of these new biologic therapies may increase the "safety zone" (or tolerance for load and excursion without dysfunctional gapping) as therapists apply stress to healing tendons and may alter future rehabilitation protocols by allowing greater angles of motion (and thus tendon excursion), increased external load, and decreased time in protective orthoses (splints). However, at this time, the stronger repair techniques and the application of controlled stress remain the best and most well-supported intervention after tendon injury and repair in the recovery of functional tendon excursion and joint range of motion. The hand therapist's role in this process remains a critical component contributing to satisfactory outcomes. PMID:22326362

Evans, Roslyn B

2012-01-01

187

Stem Cells for Augmenting Tendon Repair  

PubMed Central

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

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

2012-01-01

188

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

PubMed Central

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

A??r, ?smail; Aytekin, Mahmut Nedim; Ba??, Onur; ayp?nar, Bar??; Erol, Blent

2014-01-01

189

Tendonitis  

MedlinePLUS

... to you by the American Orthopaedic Society for Sports Medicine. They provide general information only and are not ... fact sheet or learn more about other orthopaedic sports medicine topics, please visit www.sportsmed.org. Copyright 2013. ...

190

Targeted deletion of collagen v in tendons and ligaments results in a classic ehlers-danlos syndrome joint phenotype.  

PubMed

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

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

2015-05-01

191

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

PubMed

Hand surgeons continue to search for the best surgical flexor tendon repair and treatment of the tendon sheaths and pulleys, and they are attempting to establish postoperative regimens that fit diverse clinical needs. It is the purpose of this report to present the current views, methods, and suggestions of six senior hand surgeons from six different countries - all experienced in tendon repair and reconstruction. Although certainly there is common ground, the report presents provocative views and approaches. The report reflects an update in the views of the committee. We hope that it is helpful to surgeons and therapists in treating flexor tendon injuries. PMID:23962872

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

2014-01-01

192

Decellularized Tendon Extracellular MatrixA Valuable Approach for Tendon Reconstruction?  

PubMed Central

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

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

2012-01-01

193

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

PubMed Central

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

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

2013-01-01

194

Position Control of Tendon-Driven Fingers  

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

195

Condition assessment of PC tendon duct filling by elastic wave velocity mapping.  

PubMed

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

Liu, Kit Fook; Chai, Hwa Kian; Mehrabi, Nima; Yoshikazu, Kobayashi; Shiotani, Tomoki

2014-01-01

196

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

PubMed Central

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

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

2014-01-01

197

Determining the Contribution of Glycosaminoglycans to Tendon Mechanical Properties with a Modified Shear-Lag Model  

PubMed Central

Tendon has a complex hierarchical structure composed of both a collagenous and a non-collagenous matrix. Despite several studies that have aimed to elucidate the mechanism of load transfer between matrix components, the roles of glycosaminoglycans (GAGs) remain controversial. Thus, this study investigated the elastic properties of tendon using a modified shear-lag model that accounts for the structure and non-linear mechanical response of the GAGs. Unlike prior shear-lag models that are solved either in two dimensions or in axially symmetric geometries, we present a closed-form analytical model for three-dimensional periodic lattices of fibrils linked by GAGs. Using this approach, we show that the non-linear mechanical response of the GAGs leads to a distinct toe region in the stress-strain response of the tendon. The critical strain of the toe region is shown to decrease inversely with fibril length. Furthermore, we identify a characteristic length scale, related to microstructural parameters (e.g. GAG spacing, stiffness, and geometry) over which load is transferred from the GAGs to the fibrils. We show that when the fibril lengths are significantly larger than this length scale, the mechanical properties of the tendon are relatively insensitive to deletion of GAGs. Our results provide a physical explanation for the insensitivity for the mechanical response of tendon to the deletion of GAGs in mature tendons, underscore the importance of fibril length in determining the elastic properties of the tendon, and are in excellent agreement with computationally intensive simulations. PMID:23932185

Ahmadzadeh, Hossein; Connizzo, Brianne K.; Freedman, Benjamin R.; Soslowsky, Louis J.; Shenoy, Vivek B.

2014-01-01

198

Tendon and Ligament Fixation to Bone  

Microsoft Academic Search

For the successful transplantation or transposition of ligaments and tendons, fixation techniques are very important. As most\\u000a postsurgical rehabilitation protocols emphasize immediate full range of motion and early return to function, fixation must\\u000a provide adequate strength and stiffness during the early postoperative period. Table 1 lists mechanical properties (failure\\u000a load, ultimate strength, stiffness, and elastic modulus) of ligament, tendon, or

Christopher M. Hill; Yuehuei H. An; Frank A. Young

199

Biological Augmentation of Rotator Cuff Tendon Repair  

Microsoft Academic Search

A histologically normal insertion site does not regenerate following rotator cuff tendon-to-bone repair, which is likely due\\u000a to abnormal or insufficient gene expression and\\/or cell differentiation at the repair site. Techniques to manipulate the biologic\\u000a events following tendon repair may improve healing. We used a sheep infraspinatus repair model to evaluate the effect of osteoinductive\\u000a growth factors and BMP-12 on

David Kovacevic; Scott A. Rodeo

2008-01-01

200

Right ventricular false tendons, a cadaveric approach  

Microsoft Academic Search

Left ventricular false tendons (LFTs) have been extensively described and recognized by gross anatomic studies. However, there\\u000a is very little information available regarding right ventricular false tendons (RFTs). The aim of our study, therefore, was\\u000a to explore and delineate the morphology, topography and morphometry of the RFTs, and provide a comprehensive picture of their\\u000a anatomy across a broad range of

Marios Loukas; Christopher T. Wartmann; R. Shane Tubbs; Nihal Apaydin; Robert G. Louis Jr; Brandie Black; Robert Jordan

2008-01-01

201

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

PubMed

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

Finni, T; Kovanen, V; Ronkainen, P H A; Pllnen, E; Bashford, G R; Kaprio, J; Aln, M; Kujala, U M; Sipil, S

2009-04-01

202

Tension Distribution in a Tendon-Driven Robotic Finger  

NASA Technical Reports Server (NTRS)

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.

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

2013-01-01

203

In Vivo Identity of Tendon Stem Cells and the Roles of Stem Cells in Tendon Healing  

PubMed Central

We investigated the spatial distribution of stem cells in tendons and the roles of stem cells in early tendon repair. The relationship between tendon-derived stem cells (TDSCs) isolated in vitro and tendon stem cells in vivo was also explored. Iododeoxyuridine (IdU) label-retaining method was used for labeling stem cells in rat patellar tendons with and without injury. Co-localization of label-retaining cells (LRCs) with different markers was done by immunofluorescent staining. TDSCs were isolated from patellar tendon mid-substance after IdU pulsing, and the expression of different markers in fresh and expanded cells was done by immunofluorescent staining. More LRCs were found at the peritenon and tendonbone junction compared with the mid-substance. Some LRCs at the peritenon were located at the perivascular niche. The LRC number and the expression of proliferative, tendon-related, pluripotency, and pericyte-related markers in LRCs in the window wound increased. Most of the freshly isolated TDSCs expressed IdU, and some TDSCs expressed pericyte-related markers, which were lost during expansion. Both freshly isolated and subcultured TDSCs expressed pluripotency markers, which were absent in LRCs in intact tendons. In conclusion, we identified LRCs at the peritenon, mid-substance, and tendonbone junction. There were both vascular and non-vascular sources of LRCs at the peritenon, while the source of LRCs at the mid-substance was non-vascular. LRCs participated in tendon repair via migration, proliferation, activation for tenogenesis, and increased pluripotency. Some LRCs in the window wound were pericyte like. Most of the mid-substance TDSCs were LRCs. The pluripotency markers and pericyte-related marker in LRCs might be important for function after injury. PMID:23815595

Tan, Qi; Lee, Yuk Wa

2013-01-01

204

Arthroscopic Quadriceps Tendon Repair: Two Case Reports  

PubMed Central

Recently, although some studies of open repair of the tendon of the quadriceps femoris have been published, there have been no reports in the literature on primary arthroscopic repair. In our present study, we present two cases of quadriceps tendon injury arthroscopically repaired with excellent results. Case 1 involved a 68-year-old man who was injured while shifting his weight to prevent a fall. MRI showed complete rupture at the insertion of the patella of the quadriceps tendon. The rupture was arthroscopically repaired using both suture anchor and pull-out suture fixation methods via bone tunnels (hereafter, pull-out fixation). Two years after surgery, retearing was not observed on MRI and both Japan Orthopedic Association (JOA) Knee and Lysholm scores had recovered to 100. Case 2 involved a 50-year-old man who was also injured when shifting his weight to prevent a fall. MRI showed incomplete superficial rupture at the insertion of the patella of the quadriceps tendon. The rupture was arthroscopically repaired using pull-out fixation of six strand sutures. One year after surgery, MRI revealed a healed tendon and his JOA and Lysholm scores were 95 and 100, respectively. Thus, arthroscopic repair may be a useful surgical method for repairing quadriceps tendon injury.

Saito, Hidetomo; Shimada, Yoichi; Yamamura, Toshiaki; Yamada, Shin; Sato, Takahiro; Nozaka, Koji; Kijima, Hiroaki; Saito, Kimio

2015-01-01

205

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

PubMed

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

Malvankar, S; Khan, W S

2011-12-01

206

Comparative study of the characteristics and properties of tendinocytes derived from three tendons in the equine forelimb.  

PubMed

The aim of this study was to determine the characteristic differences in tendinocytes derived from tendons in the equine forelimb, superficial digital flexor tendon (SDFT), deep digital flexor tendon (DDFT) and common digital extensor tendon (CDET), in morphology, proliferation, collagen production ability and ability for synthesis of matrix metalloproteinases (MMPs). Significant differences were observed in cell number in vivo. The cellular number was largest in the SDFT and smallest in the CDET. The values of in vitro proliferation ratios and ability for synthesis of collagen and MMPs were largest in the SDFT and smallest in the CDET. Addition of TNFalpha to culture of all three types of tendinocytes increased the synthesis of both proMMP-9 (except CDET) and collagen and decreased proMMP-13 synthesis and had no effect on proMMP-2 synthesis. Flexor tendons in forelimbs (SDFT and DDFT) restore energy during locomotion and are more easily injured than are extensor tendons. This structural property would cause active ECM and MMPs synthesis. And CDET have very low turnover potential; in the small number of cells, low cellular proliferation, lower ability for synthesis of collagen and MMPs. The isolated tendinocytes provided much information on the characteristics and properties of tendons for the ECM turnover system and responsiveness of tendinocytes to complex inflammatory responses in tendinopathy. PMID:19640554

Hosaka, Yoshinao Z; Takahashi, Hideyuki; Uratsuji, Takehiro; Tangkawattana, Prasarn; Ueda, Hiromi; Takehana, Kazushige

2010-02-01

207

Flexural behavior of steel I-beam prestressed with externally unbonded tendons  

Microsoft Academic Search

The external post-tensioning technique has been commonly used in the construction field because it facilitates the analysis of structures and is widely applicable for many types of structures. In this paper, the flexural behavior and strengthening effect of a bridge were studied using a steel I-beam that had been externally prestressed with unbonded tendons. Eleven steel beams were fabricated and

Taewan Kim; Kwangsoo Kim; Sung-Nam Hong

2010-01-01

208

Bio-engineered synovial membrane to prevent tendon adhesions in rabbit flexor tendon model.  

PubMed

During tendon injuries, the tendon sheath is also damaged. This study aims to test effectiveness of engineered tendon synovial cell biomembrane on prevention of adhesions. Forty New Zealand Rabbits enrolled into four study groups. Engineered synovial sheath was produced by culturing cell suspension on fabricated collagen matrix membrane. Study groups were: tendon repair (group A), tendon repair zone covered with plane matrix (Group B), synovial suspension injection into the zone of repair over matrix (Group C), and biomembrane application (Group D). Biomechanical evaluations of tendon excursion, metacarpophalangeal and proximal interphalangeal joints range of motion, H&E and Alcian Blue with neutral red staining, and adhesion formation graded for histological assessments were studied. Ten non-operated extremities used as control. Tendon excursions and range of motions were significantly higher and close to control group for Group D, p??0.005. Hyaluronic acid synthesis was demonstrated at groups C and D at the zone of injury. Application of synovial cells into the tendon repair zone either by cell suspension or within a biomembrane significantly decreases the adhesion formation. Barrier effect of collagen matrix and restoration of hyaluronic acid synthesis can explain the possible mechanism of action. PMID:24616375

Baymurat, Alim Can; Ozturk, Akif Muhtar; Yetkin, Haluk; Ergun, Mehmet Ali; Helvac?oglu, Fatma; Ozk?z?lc?k, Asya; Tuzlako?lu, Kadriye; ?ener, E Ertugrul; Erdogan, Deniz

2015-01-01

209

Effects of Synergistic Massage and Physical Exercise on the Expression of Angiogenic Markers in Rat Tendons  

PubMed Central

Physical exercise and massage are regarded as key factors in regulating tendon structure. However, information on the mechanism through which massage influences the structure and biology of a tendon is scarce. In this study, we attempted to define the impact of these two activities on rat tendons by using morphological and molecular techniques, determining the expression of VEGF-A, FGF-2, and CD34 in the tendons of rats subjected to 10 weeks of physical exercise (running) with massage of varied duration. The group of rats that was trained and massaged during the entire study was characterized by the highest expression of these markers, compared to the rats subjected to massage before training and to the control group subjected to physical exercises only. The greatest significant differences, compared to the control, were noted in the expression of all the studied markers at mRNA level, and in the case of VEGF-A, at protein level, in the third and fifth weeks of the experiment. The results of this study could point to the synergistic impact of simultaneous massage and physical exercise on the expression of angiogenesis markers in rat tendons. PMID:24900996

Andrzejewski, Waldemar; Kassolik, Krzysztof; Dziegiel, Piotr; Pula, Bartosz; Ratajczak-Wielgomas, Katarzyna; Jablonska, Karolina; Kurpas, Donata; Halski, Tomasz; Podhorska-Okolow, Marzena

2014-01-01

210

A pathomechanical concept explains muscle loss and fatty muscular changes following surgical tendon release.  

PubMed

Following tendon tear, the musculo-tendinous unit retracts permanently, looses muscle fibre volume and is infiltrated with fat. This is currently considered to be an unexplained degenerative process. In a sheep model of chronic tendon tear with delayed tendon repair (35 weeks after tendon release), we studied the nature of these muscle changes in eight experimental animals. At sacrifice (75 weeks after tendon release) the muscle had retracted by 1.7+/-0.5 cm (9% of entire length, p<0.0001), the pennation angle had increased from 22+/-2.5 degrees to 50+/-11 degrees (p<0.0001) and the mean muscle fibre length had shortened from 32+/-3 to 16+/-5 mm (50%, p<0.0001). In electron and light microscopy, we found essentially normal muscle fibres with an unaltered fibre diameter and myofibrillar structure, while interstitial fat and fibrous tissue had increased from 3.9% to 45.9% (p<0.0001) of the muscle volume. Geometric modelling showed that the increase of the pennation angle separates the muscle fibre bundles mechanically like limbs of a parallelogram. Infiltrating fat cells fill the created space between the reoriented muscle fibres which may be quantitatively calculated without affecting the structural properties of the muscle cells. Fatty infiltration is therefore not seen as a degenerative process but a necessary rearrangement of the tissue after macroarchitectural changes caused by musculo-tendinous retraction. PMID:15304272

Meyer, Dominik C; Hoppeler, Hans; von Rechenberg, Brigitte; Gerber, Christian

2004-09-01

211

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

PubMed

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 not significantly reduced by BtxA-unloading, while, strength, modulus, and toughness were 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

Schwartz, A G; Lipner, J H; Pasteris, J D; Genin, G M; Thomopoulos, S

2013-07-01

212

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

PubMed

Tendinous tissues respond to chronic unloading with adaptive changes in mechanical, elastic, and morphological properties. However, little is known about the changes in the detailed structures of the entire tendinous tissue and whether the change in tendon stiffness is related to morphology. We investigated changes in dimensional (volume, cross-sectional area, segmented lengths) and elastic (Young's modulus) properties of the Achilles tendon and distal aponeurosis in response to chronic unilateral lower limb suspension (ULLS) using velocity encoded phase contrast (VE-PC) and three-dimensional morphometric magnetic resonance imaging (MRI). Five healthy subjects underwent ULLS for 4 wk. Axial morphometric MRI was acquired along the entire length from the calcaneous to the medial gastrocnemius insertion. An oblique sagittal VE-PC MRI was also acquired. The Young's modulus could be calculated from this cine dynamic sequence of velocity encoded images from the slope of the stress-strain curve during the submaximal isometric plantar flexion. After 4 wk of ULLS, we found significant (46.7%) decrease in maximum plantar flexion torque. The total volumes of entire tendinous tissue (determined as the sum of the Achilles tendon and distal aponeurosis) increased significantly by 6.4% (11.9 vs. 12.7 ml) after ULLS. In contrast, Young's modulus decreased significantly by 10.4% (211.7 vs. 189.6 MPa) for the Achilles tendon and 29.0% for the distal aponeurosis (158.8 vs. 113.0 MPa) following ULLS. There was no significant correlation between relative change in volume and Young's modulus with 4 wk of ULLS. It is suggested that, although tendon hypertrophy can be expected to adversely affect tendon stiffness, the absence of any significant correlation between the magnitude of tendon hypertrophy and reduced Young's modulus indicates that dimensional factors were not critical to the elastic properties. PMID:20616227

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

2010-09-01

213

Comparison of femoral fixation methods for anterior cruciate ligament reconstruction with patellar tendon graft: a mechanical analysis in porcine knees  

Microsoft Academic Search

The aim of the present study was to evaluate the structural properties of femurpatellar tendon graft complex in anterior\\u000a cruciate ligament (ACL) reconstruction using different femoral fixation devices. Type of study is biomechanical testing. An\\u000a ACL reconstruction was performed on 40 cadaver porcine knees, using patellar tendon (PT) graft. Specimens were divided into\\u000a four groups according to the femoral fixation:

Giuseppe Milano; Pier Damiano Mulas; Fabio Ziranu; Laura Deriu; Carlo Fabbriciani

2007-01-01

214

Specialization of tendon mechanical properties results from interfascicular differences  

PubMed Central

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

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

2012-01-01

215

21 CFR 888.3025 - Passive tendon prosthesis.  

Code of Federal Regulations, 2013 CFR

...SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices 888.3025 Passive tendon prosthesis. (a...new tendon sheath. The device is not intended as a permanent implant nor to function as a replacement for the ligament or...

2013-04-01

216

Biology and augmentation of tendon-bone insertion repair  

Microsoft Academic Search

Surgical reattachment of tendon and bone such as in rotator cuff repair, patellar-patella tendon repair and anterior cruciate ligament (ACL) reconstruction often fails due to the failure of regeneration of the specialized tissue (\\

Pauline Po-Yee Lui; Peng Zhang; Kai-Ming Chan; Ling Qin

2010-01-01

217

21 CFR 888.3025 - Passive tendon prosthesis.  

Code of Federal Regulations, 2011 CFR

...Passive tendon prosthesis. (a) 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...

2011-04-01

218

Damage Mechanics of Porcine Flexor Tendon: Mechanical Evaluation and Modeling  

E-print Network

Damage Mechanics of Porcine Flexor Tendon: Mechanical Evaluation and Modeling SARAH DUENWALD of this article. Abstract--Porcine flexor tendons underwent cyclic and stress relaxation testing before and after

Lakes, Roderic

219

21 CFR 888.3025 - Passive tendon prosthesis.  

Code of Federal Regulations, 2010 CFR

...Passive tendon prosthesis. (a) 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...

2010-04-01

220

21 CFR 888.3025 - Passive tendon prosthesis.  

Code of Federal Regulations, 2014 CFR

...FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices 888.3025 Passive tendon prosthesis. (a) Identification. A passive tendon prosthesis is...

2014-04-01

221

21 CFR 888.3025 - Passive tendon prosthesis.  

Code of Federal Regulations, 2012 CFR

...FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices 888.3025 Passive tendon prosthesis. (a) Identification. A passive tendon prosthesis is...

2012-04-01

222

Robot Arm with Tendon Connector Plate and Linear Actuator  

NASA Technical Reports Server (NTRS)

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.

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

2014-01-01

223

Human collagen-based multilayer scaffolds for tendon-to-bone interface tissue engineering.  

PubMed

The natural tendon-to-bone region has a gradient in structure and composition, which is translated into a spatial variation of chemical, physical, and biological properties. This unique transitional tissue between bone and tendon is not normally recreated during natural bone-to-tendon healing. In this study, we have developed a human collagen-based multilayer scaffold mimicking the tendon-to-bone region. The scaffold consists of four different layers with the following composition gradient: (a) a tendon layer composed of collagen; (b) an uncalcified fibrocartilage layer composed of collagen and chondroitin sulfate; (c) a calcified fibrocartilage layer composed of collagen and less apatite; (d) a bone layer composed of collagen and apatite. The chemical, physical, and mechanical properties of the scaffold were characterized by a scanning electron microscope, porosimeter, universal tensile machine, Fourier transform infrared spectrometer, energy dispersive X-ray analysis apparatus, and thermogravimetric analysis apparatus. The multilayer scaffold provided a gradual transition of the physical, chemical, and mechanical environment and supported the adhesion and proliferation of human fibroblasts, chondrocytes, and osteoblasts toward each corresponding matrix. Overall, our results suggest the feasibility of a human collagen-based multilayer scaffold for regeneration of hard-to-soft interface tissues. PMID:24327550

Kim, Beob Soo; Kim, Eun Ji; Choi, Ji Suk; Jeong, Ji Hoon; Jo, Chris Hyunchul; Cho, Yong Woo

2014-11-01

224

Metabolic activity and collagen turnover in human tendon in response to physical activity.  

PubMed

Connective tissue of the human tendon plays an important role in force transmission. The extracellular matrix turnover of tendon is influenced by physical activity. Blood flow, oxygen demand, and the level of collagen synthesis and matrix metalloproteinases increase with mechanical loading. Gene transcription and especially post-translational modifications of proteins of the extracellular matrix are enhanced following exercise. Conversely, inactivity markedly decreases collagen turnover. Training leads to a chronically increased collagen turnover, and dependent on the type of collagen also to some degree of net collagen synthesis. These changes modify the biomechanical properties of the tissue (for example, viscoelastic characteristics) as well as the structural properties of the in collagen (for example, cross-sectional area). Mechanical loading of human tendon does result in a marked interstitial increase in growth factors that are known potentially to stimulate synthesis of collagen and other extracellular matrix proteins. Taken together, human tendon tissue mounts a vigorous acute and chronic response to mechanical loading in terms of metabolic-circulatory changes as well as of extracellular matrix formation. These changes may contribute to training-induced adaptation of biomechanical properties consisting of altered resistance to loading and enhanced tolerance to strenuous exercise. Understanding of such changes is a pre-requisite in the development of measures aimed at prevention of overuse tendon injuries occurring during sport, work or leisure-related activities. PMID:15788870

Kjaer, M; Langberg, H; Miller, B F; Boushel, R; Crameri, R; Koskinen, S; Heinemeier, K; Olesen, J L; Dssing, S; Hansen, M; Pedersen, S G; Rennie, M J; Magnusson, P

2005-03-01

225

Modified Rerouting Procedure for Failed Peroneal Tendon Dislocation Surgery  

Microsoft Academic Search

\\u000a AbstractRecurrent dislocation of the peroneal tendons following operative treatment is relatively uncommon, but can be difficult to\\u000a treat. We asked whether subligamental transposition of the peroneus brevis tendon, fibular grooving, and reattachment of the\\u000a superior peroneal retinaculum for failed peroneal tendon dislocation surgery would achieve a stable fixation of the peroneal\\u000a tendons and whether there would be restrictions of ROM

R. Gaulke; F. Hildebrand; M. Panzica; T. Hfner; C. Krettek

2010-01-01

226

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

PubMed Central

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

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

2015-01-01

227

Tissue-scale anisotropy and compressibility of tendon in semi-confined compression tests.  

PubMed

In this study, porcine tendon tissue was tested with a dedicated semi-confined compression set-up that enables us to induce states of either fibrils in compression (mode I), tension (mode II) or at constant length (mode III), respectively. The results suggest that tendon tissue is compressible and demonstrates a significantly stiffer response in mode I than in mode III. This implies that the fibril direction remains the axis of transverse isotropy in compression and that it provides an anisotropic contribution to the tissue stress. These results, which are important for the development of constitutive models for tendon tissue, are discussed with respect to the hierarchical structure of the extracellular matrix. PMID:25660384

Bl, Markus; Ehret, Alexander E; Leichsenring, Kay; Ernst, Michael

2015-04-13

228

CORROSION OF POST-TENSIONED TENDONS IN FLORIDA BRIDGES  

Microsoft Academic Search

Severe corrosion distress and failures in post-tensioned tendons has been found in two major bridges in the State of Florida. Corrosion distress and complete tendon failure has been identified in horizontally oriented tendons that support pre-cast bridge superstructure box segments. In virtually all instances, the observed corrosion has been associated with the presence of grout voids and visual evidence of

Rodney G. Powers; Alberto A. Sags; Yash Paul Virmani

229

Early active mobilization after second stage flexor tendon grafts  

Microsoft Academic Search

We assessed the results of nine two-stage tendon reconstructions. The tendon graft was the ipsilateral palmaris longus tendon inserted into a tunnel which had been previously created by a silicone spacer. Early active mobilization was commenced 48 hours after surgery according to a previously described protocol (Small et al, 1989). Using the grading system of Kleinert and Verdan (1983) the

K. Khan; M. Riaz; M. S. C. Murison; M. D. Brennen

1997-01-01

230

Flexor tendon repairs: techniques, eponyms, and evidence.  

PubMed

The evolution in surgical technique and suture technology has provided an abundance of options for flexor tendon repairs. Multiple biomechanical studies have attempted to identify the best surgical technique based on suture properties, technical modifications, and repair configurations. However, the burgeoning amount of research on flexor tendon repairs has made it difficult to follow, and no gold standard has been determined for the optimal repair algorithm. Therefore, it seems that repairs are usually chosen based on a combination of familiarity from training, popularity, and technical difficulty. We will discuss the advantages, disadvantages, and technical aspects of some of the most common core flexor tendon repairs in the literature. We will also highlight the nomenclature carried through the years, drawings of the repairs referred to by that nomenclature, and the data that support those repairs. PMID:25154573

Chauhan, Aakash; Palmer, Bradley A; Merrell, Gregory A

2014-09-01

231

Tendon-Derived Stem Cells (TDSCs): From Basic Science to Potential Roles in Tendon Pathology and Tissue Engineering Applications  

Microsoft Academic Search

Traditionally, tendons are considered to only contain tenocytes that are responsible for the maintenance, repair and remodeling\\u000a of tendons. Stem cells, which are termed tendon-derived stem cells (TDSCs), have recently been identified in tendons. This\\u000a review aims to summarize the current information about the in vitro characteristics of TDSCs, including issues related to TDSC isolation and culture, their cell morphology,

Pauline Po Yee Lui; Kai Ming Chan

232

Magnetic resonance imaging of the elbow. Part II: Abnormalities of the ligaments, tendons, and nerves  

Microsoft Academic Search

Part II of this comprehensive review on magnetic resonance imaging of the elbow discusses the role of magnetic resonance imaging in evaluating patients with abnormalities of the ligaments, tendons, and nerves of the elbow. Magnetic resonance imaging can yield high-quality multiplanar images which are useful in evaluating the soft tissue structures of the elbow. Magnetic resonance imaging can detect tears

Richard Kijowski; Michael Tuite; Matthew Sanford

2005-01-01

233

Sacrificial Bonds in Polymer Brushes from Rat Tail Tendon Functioning as Nanoscale Velcro  

E-print Network

Sacrificial Bonds in Polymer Brushes from Rat Tail Tendon Functioning as Nanoscale Velcro Thomas polymer properties is crucial for an understanding of the structure and functional mechanisms of California, Santa Barbara, California 93101 ABSTRACT Polymers play an important role in many biological

Fygenson, Deborah Kuchnir

234

Connecting muscles to tendons: tendons and musculoskeletal development in flies and vertebrates  

E-print Network

and the exoskeleton in invertebrates. Here, we discuss recent findings that illuminate musculoskeletal assembly connectivity between muscles and the exoskeleton. Intriguingly, tendon-like cells develop within the ectoderm

235

Gene expression in distinct regions of rat tendons in response to jump training combined with anabolic androgenic steroid administration.  

PubMed

The aim of this study was to evaluate the expression of key genes responsible for tendon remodeling of the proximal and distal regions of calcaneal tendon (CT), intermediate and distal region of superficial flexor tendon (SFT) and proximal, intermediate and distal region of deep flexor tendon (DFT) submitted to 7weeks of jumping water load exercise in combination with AAS administration. Wistar male rats were grouped as follows: sedentary (S), trained (jumping water load exercise) (T), sedentary animals treated with AAS (5mg/kg, twice a week) and animals treated with AAS and trained (AAST). mRNA levels of COL1A1, COL3A1, TIMP-1, TIMP-2, MMP-2, IGF-IEa, GAPDH, CTGF and TGF-?-1 were evaluated by quantitative PCR. Our main results indicated that mRNA levels alter in different regions in each tendon of sedentary animals. The training did not alter the expression of COL1A1, COL3A, IGF-IEa and MMP-2 genes, while AAS administration or its combination with training reduced their expression. This study indicated that exercise did not alter the expression of collagen and related growth factors in different regions of rat tendon. Moreover, the pattern of gene expression was distinct in the different tendon regions of sedentary animals. Although, the RNA yield levels of CT, SFT and DFT were not distinct in each region, these regions possess not only the structural and biochemical difference, but also divergence in the expression of key genes involved in tendon adaptation. PMID:21842416

Marqueti, Rita Cssia; Marqueti, Rita de Cssia; Heinemeier, Katja Maria; Durigan, Joo Luiz Quaglioti; de Andrade Perez, Srgio Eduardo; Schjerling, Peter; Kjaer, Michael; Carvalho, Hernandes Faustino; Selistre-de-Araujo, Heloisa Sobreiro

2012-04-01

236

Effect of hydrogen peroxide on human tendon allograft.  

PubMed

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 5min 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

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

2013-12-01

237

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

PubMed Central

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

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

2015-01-01

238

Zone I extensor reconstruction with tendon salvaged from another finger.  

PubMed

Laceration, crush, and avulsion injuries are common acute extensor tendon injuries. Simple lacerations may often be repaired in the emergency room, but crush or avulsion injuries may involve tendon loss and gaps in the extensor tendons. Reconstruction can be difficult. The purpose of this article is to present a salvage technique for reconstruction of large extensor tendon gaps in extensor zone I in patients with severe injuries to multiple fingers. This technique, in which a tendon is transplanted from an unsalvageable finger to another with a terminal tendon gap in the same patient, may be a reasonable remedy for reconstruction of tendon loss or gaps and may offer advantages over other traditional reconstructive techniques in certain cases. PMID:24613590

Trker, Tolga; Capdarest-Arest, Nicole; Schmahl, Dennis T

2014-05-01

239

Abductor pollicis longus tendon division with swan neck thumb deformity.  

PubMed

Swan neck thumb deformity can be caused by osteoarthritis, rheumatoid arthritis, systemic lupus erythematosus, tendon transfers and paralytic diseases. Abductor pollicis longus is one of the major stabilizing tendon of the carpometacarpal joint of thumb. To the best of our knowledge, swan neck thumb deformity owing to division of abductor pollicis longus tendon is rare. In this article, we describe a case of isolated division of abductor pollicis longus tendon presenting with swan-neck deformity of thumb and discuss the mechanism, management and outcome. The patient was treated by repair of the divided tendon using palmaris longus tendon graft. At approximately 107weeks following treatment, the patient was having full range of thumb movement and the deformity completely disappeared. We also describe the unusual mechanism whereby an isolated division of abductor pollicis longus tendon results in swan neck thumb deformity. Level of clinical evidence IV. PMID:22825877

Zacharia, Balaji; Puthezhath, Kishore

2012-08-01

240

Variation in the insertion of the palmaris longus tendon.  

PubMed

The palmaris longus is harvested as a tendon graft in various surgical procedures. We herein report the variations in the insertion of the palmaris longus tendon. During a routine dissection, a rare variation in the insertion of the palmaris longus tendon was observed. In the left forearm, the palmaris longus tendon bifurcated, while in the right forearm, the palmaris longus tendon trifurcated, giving rise to an accessory muscle, which passed superficial to the ulnar artery and ulnar nerve. The accessory muscle was supplied by a deep branch of the ulnar nerve, and the ulnar artery was observed to be tortuous. During reconstructive surgeries, surgeons should bear in mind the accessory muscle. Also, since the palmaris longus muscle provides a very useful graft in tendon surgery, every surgeon should be aware of the variations in the insertion of the palmaris longus tendon. PMID:25640108

Sunil, Vinutha; Rajanna, Shubha; Gitanjali; Kadaba, Jayanthi

2015-01-01

241

The influence of noncollagenous matrix components on the micromechanical environment of tendon fascicles.  

PubMed

Tendon is composed of type I collagen fibers, interspersed with proteoglycan matrix and cells. Glycosaminoglycans may play a role in maintaining the structural integrity of tendon, preventing excessive shearing between collagen components. This study tests the hypothesis that tendon extension mechanisms can be altered by modifying the composition of noncollagenous matrix. Tendon explants were treated with phosphate buffered saline (PBS) or PBS + 0.5 U ml(-1) chondroitinase ABC. Structural changes were examined using TEM and biochemical analysis, while strain response was examined using confocal microscopy and gross mechanical characterization. Chondroitinase ABC removed 90% of glycosaminoglycans from the matrix. Results demonstrated significant swelling of fibrils and surrounding matrix when incubated in either solution. In response to applied strain, PBS incubated samples demonstrated significantly less sliding between adjacent fibers than nonincubated, and a 33% reduction in maximum force. By contrast, fascicles incubated in chondroitinase ABC demonstrated a similar strain response to nonincubated. Data indicate that collagen-proteoglycan binding characteristics can be influenced by incubation and this, in turn, can influence the preferred extension mechanisms adopted by fascicles. This highlights the importance of maintaining fascicles within their natural environment to prevent structural or mechanical changes prior to subsequent analysis. PMID:16133917

Screen, Hazel R C; Shelton, Julia C; Chhaya, Vivek H; Kayser, Michael V; Bader, Dan L; Lee, David A

2005-08-01

242

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

PubMed Central

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

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

2011-01-01

243

How tendons buffer energy dissipation by muscle  

PubMed Central

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

Roberts, Thomas J.; Konow, Nicolai

2013-01-01

244

Prestressed concrete using KEVLAR reinforced tendons  

Microsoft Academic Search

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

Dolan

1989-01-01

245

Functional postoperative treatment of Achilles tendon repair  

Microsoft Academic Search

Twenty-one patients with surgically repaired Achilles tendon tears that were treated postoperatively with a functional orthosis rather than routine cast immobiliza tion were evaluated. The orthosis allowed unrestricted plantar flexion and limited dorsiflexion to neutral. Toe- touch weightbearing crutch ambulation was allowed immediately and was gradually increased over the 6 to 8 weeks of treatment. Of the 21 patients, 14

Thomas R. Carter; Peter J. Fowler; Cathy Blokker

1992-01-01

246

Achilles tendon pathology, present and future  

Microsoft Academic Search

Lecture 18IntroductionThe recent progress in molecular biology, could make possible to identify the factors which influence the metabolism of the tenocytes and promote their natural healing process. The role of growth factors in the healing of tendons, for example, is still unclear, although basic fibroblast growth factor can stimulate healing by promoting cell proliferation and synthesis of the matrix. Gene

N Maffulli

2011-01-01

247

Biologics in Achilles tendon healing and repair: a review.  

PubMed

Injuries of the Achilles tendon are relatively common with potentially devastating outcomes. Healing Achilles tendons form a fibrovascular scar resulting in a tendon which may be mechanically weaker than the native tendon. The resulting strength deficit causes a high risk for reinjury and other complications. Treatments using biologics aim to restore the normal properties of the native tendon and reduce the risk of rerupture and maximize tendon function. The purpose of this review was to summarize the current findings of various therapies using biologics in an attempt to improve the prognosis of Achilles tendon ruptures and tendinopathies. A PubMed search was performed using specific search terms. The search was open for original manuscripts and review papers limited to publication within the last 10years. From these searches, papers were included in the review if they investigated the effects of biological augmentation on Achilles tendon repair or healing. Platelet-rich plasma may assist in the healing process of Achilles tendon ruptures, while the evidence to support its use in the treatment of chronic Achilles tendinopathies remains insufficient. The use of growth factors such as hepatocyte growth factor, recombinant human platelet-derived growth factor-BB, interleukin-6, and transforming growth factor beta as well as several bone morphogenetic proteins have shown promising results for Achilles tendon repair. In vitro and preclinical studies have indicated the potential effectiveness of bone marrow aspirate as well. Stem cells also have positive effects on Achilles tendon healing, particularly during the early phases. Polyhydroxyalkanoates (PHA), decellularized tendon tissue, and porcine small intestinal submucosa (SIS) are biomaterials which have shown promising results as scaffolds used in Achilles tendon repair. The application of biological augmentation techniques in Achilles tendon repair appears promising; however, several techniques require further investigation to evaluate their clinical application. PMID:25655258

Shapiro, Evan; Grande, Daniel; Drakos, Mark

2015-03-01

248

Nuclear magnetic resonance study of the collagen matrix in tendon  

NASA Astrophysics Data System (ADS)

Understanding of complex interactions of water with macromolecules is a prerequisite for quantitative musculoskeletal imaging and this dissertation presents a study on NMR characteristics of water in anisotropic environment of the collagen extracellular matrix of tendon. The first chapter of the dissertation analyzes a "magic angle" effect, a well known in clinical practice artifact of a sudden signal increase in normal tendons and ligaments at the orientation of 55 with respect to the static magnetic field of an MRI scanner. The physical basis of the orientation dependence of the free induction decay is studied in ex-vivo mammalian tissue at the field strength of 2 Tesla. Obtained quantitative measures are related to the model of heterogeneous water phases in the collagen extracellular matrix of tendon. A novel effect of central frequency shift of the water signal is reported and hypothesis on the origin of the effect is put forward. Clinical applications of NMR and MRI constantly benefit from adopting methods and techniques from the field of NMR of liquids, solids and liquid crystals. In the second chapter, a pseudo solid echo technique is evaluated for the purpose of detecting slow motions in the collagen matrix at different hydration and temperatures, at the field strength of 11.74 Tesla (500 MHz). The pseudo solid echo is shown capable in detecting motions on the scale of 10-3-10-6 seconds. 1H spin-lattice relaxation study at different levels of hydration and temperatures is presented in the third chapter. Predictions of the molecular model of collagen hydration are verified at the field strength of 11.74 Tesla (500 MHz) and temperature of 6C, 26C and 37C. In the fourth chapter, an efficient adaptive mesh numerical code is developed on the basis of the octal tree data structure for assessment of the bulk magnetic susceptibility effects. The code allows calculation of the microscopic magnetic field as "seen by the nucleus" for uniformly magnetized objects of arbitrary shapes. It is applied to test two hypotheses related to the bulk susceptibility shifts in tendon as it was evidenced by the study described in the first chapter.

Krasnosselskaia, Lada Vadimovna

249

Two-staged extensor tendon reconstruction for zone 6 extensor tendon loss of the fingers: indications, technique and results.  

PubMed

Over a 20-year period, six patients (19 tendons) underwent two-staged extensor tendon reconstruction using silicone rods followed by palmaris longus tendon grafts sutured proximally to the divided flexor carpi radialis tendon. All patients were young men (mean age, 22 years) who sustained the injury in car accidents. The soft tissue loss from the dorsum of the hand was associated with extensor tendon loss over the entire zone 6 with or without loss in zone 7. Primary soft tissue coverage was done elsewhere, and patients presented for secondary tendon reconstruction. All patients had supple metacarpophalangeal joints before reconstruction. After the two-staged tendon reconstruction, full or near-full active flexion at the metacarpophalangeal joints was obtained in all patients. However, minor extension lags (10-15) at the metacarpophalangeal joints were seen in 15 out of 19 reconstructed fingers. PMID:24369363

Al-Qattan, M M

2015-03-01

250

Fabrication of Electrospun Poly(L-Lactide-co-?-Caprolactone)/Collagen Nanoyarn Network as a Novel, Three-Dimensional, Macroporous, Aligned Scaffold for Tendon Tissue Engineering  

PubMed Central

Tissue engineering techniques using novel scaffolding materials offer potential alternatives for managing tendon disorders. An ideal tendon tissue engineered scaffold should mimic the three-dimensional (3D) structure of the natural extracellular matrix (ECM) of the native tendon. Here, we propose a novel electrospun nanoyarn network that is morphologically and structurally similar to the ECM of native tendon tissues. The nanoyarn, random nanofiber, and aligned nanofiber scaffolds of a synthetic biodegradable polymer, poly(l-lactide-co-?-caprolactone) [P(LLA-CL)], and natural collagen I complex were fabricated using electrospinning. These scaffolds were characterized in terms of fiber morphology, pore size, porosity, and chemical and mechanical properties for the purpose of culturing tendon cells (TCs) for tendon tissue engineering. The results indicated a fiber diameter of 63281?nm for the random nanofiber scaffold, 64397?nm for the aligned nanofiber scaffold, and 64168?nm for the nanoyarn scaffold. The yarn in the nanoyarn scaffold was twisted by many nanofibers similar to the structure and inherent nanoscale organization of tendons, indicating an increase in the diameter of 9.513.62??m. The nanoyarn scaffold also contained 3D aligned microstructures with large interconnected pores and high porosity. Fourier transform infrared analyses revealed the presence of collagen in the three scaffolds. The mechanical properties of the sample scaffolds indicated that the scaffolds had desirable mechanical properties for tissue regeneration. Further, the results revealed that TC proliferation and infiltration, and the expression of tendon-related ECM genes, were significantly enhanced on the nanoyarn scaffold compared with that on the random nanofiber and aligned nanofiber scaffolds. This study demonstrates that electrospun P(LLA-CL)/collagen nanoyarn is a novel, 3D, macroporous, aligned scaffold that has potential application in tendon tissue engineering. PMID:23557537

Xu, Yuan; Wu, Jinglei; Wang, Haoming; Li, Hanqin; Di, Ning; Song, Lei; Li, Sontao; Li, Dianwei; Xiang, Yang; Liu, Wei

2013-01-01

251

Fascicles from energy-storing tendons show an age-specific response to cyclic fatigue loading  

PubMed Central

Some tendons, such as the human Achilles and equine superficial digital flexor tendon (SDFT), act as energy stores, stretching and recoiling to increase efficiency during locomotion. Our previous observations of rotation in response to applied strain in SDFT fascicles suggest a helical structure, which may provide energy-storing tendons with a greater ability to extend and recoil efficiently. Despite this specialization, energy-storing tendons are prone to age-related tendinopathy. The aim of this study was to assess the effect of cyclic fatigue loading (FL) on the microstructural strain response of SDFT fascicles from young and old horses. The data demonstrate two independent age-related mechanisms of fatigue failure; in young horses, FL caused low levels of matrix damage and decreased rotation. This suggests that loading causes alterations to the helix substructure, which may reduce their ability to recoil and recover. By contrast, fascicles from old horses, in which the helix is already compromised, showed greater evidence of matrix damage and suffer increased fibre sliding after FL, which may partially explain the age-related increase in tendinopathy. Elucidation of helix structure and the precise alterations occurring owing to both ageing and FL will help to develop appropriate preventative and repair strategies for tendinopathy. PMID:24402919

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

2014-01-01

252

Fascicles from energy-storing tendons show an age-specific response to cyclic fatigue loading.  

PubMed

Some tendons, such as the human Achilles and equine superficial digital flexor tendon (SDFT), act as energy stores, stretching and recoiling to increase efficiency during locomotion. Our previous observations of rotation in response to applied strain in SDFT fascicles suggest a helical structure, which may provide energy-storing tendons with a greater ability to extend and recoil efficiently. Despite this specialization, energy-storing tendons are prone to age-related tendinopathy. The aim of this study was to assess the effect of cyclic fatigue loading (FL) on the microstructural strain response of SDFT fascicles from young and old horses. The data demonstrate two independent age-related mechanisms of fatigue failure; in young horses, FL caused low levels of matrix damage and decreased rotation. This suggests that loading causes alterations to the helix substructure, which may reduce their ability to recoil and recover. By contrast, fascicles from old horses, in which the helix is already compromised, showed greater evidence of matrix damage and suffer increased fibre sliding after FL, which may partially explain the age-related increase in tendinopathy. Elucidation of helix structure and the precise alterations occurring owing to both ageing and FL will help to develop appropriate preventative and repair strategies for tendinopathy. PMID:24402919

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

2014-03-01

253

Prevalence and possible pathological significance of calcium phosphate salt accumulation in tendon matrix degeneration  

Microsoft Academic Search

OBJECTIVES: To investigate the prevalence of calcium phosphate mineral salt accumulation in degenerative supraspinatus 'tendinitis' compared with a normal sample of human tendons, and to determine whether there is an association of calcium salt deposition with pathological changes in the tendon extracellular matrix. METHODS: Cadaver tendons (supraspinatus and common biceps tendons, n = 96) and fragments of supraspinatus tendons obtained

G P Riley; R L Harrall; C R Constant; T E Cawston; B L Hazleman

1996-01-01

254

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

PubMed Central

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

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

2012-01-01

255

Identity of tendon stem cells how much do we know?  

PubMed Central

Tendon stem cells are multi-potent adult stem cells with broad differentiation plasticity that render them of great importance in cell-based therapies for the repair of tendons. We called them tendon-derived stem cells (TDSCs) to indicate the tissue origin from which the stem cells were isolated in vitro. Based on the work of other sources of MSCs and specific work on TDSCs, some properties of TDSCs have been characterized / implicated in vitro. Despite these findings, tendon stem cells remained controversial cells. This was because MSCs residing in different organs, although very similar, were not identical cells. There is evidence of differences in stem cell-related properties and functions related to tissue origins. Similar to other stem cells, tendon stem cells were identified and characterized in vitro. Their in vivo identities, niche (both anatomical locations and regulators) and roles in tendons were less understood. This review aims to summarize the current evidence of the possible anatomical locations and niche signals regulating the functions of tendon stem cells in vivo. The possible roles of tendon stem cells in tendon healing and non-healing are presented. Finally, the potential strategies for understanding the in vivo identity of tendon stem cells are discussed. PMID:23279609

Lui, Pauline Po Yee

2013-01-01

256

Foot posture is associated with morphometry of the peroneus longus muscle, tibialis anterior tendon, and Achilles tendon.  

PubMed

The aim of this study was to investigate the association between foot type and the morphometry of selected muscles and tendons of the lower limb. Sixty-one healthy participants (31 male, 30 female; aged 27.1 8.8 years) underwent gray-scale musculoskeletal ultrasound examination to determine the anterior-posterior (AP) thickness of tibialis anterior, tibialis posterior, and peroneus longus muscles and tendons as well as the Achilles tendon. Foot type was classified based on arch height and footprint measurements. Potentially confounding variables (height, weight, hip and waist circumference, rearfoot and ankle joint range of motion, and levels of physical activity) were also measured. Multiple linear regression models were used to determine the association between foot type with muscle and tendon morphometry accounting for potentially confounding variables. Foot type was significantly and independently associated with AP thickness of the tibialis anterior tendon, peroneus longus muscle, and Achilles tendon, accounting for approximately 7% to 16% of the variation. Flat-arched feet were associated with a thicker tibialis anterior tendon, a thicker peroneus longus muscle, and a thinner Achilles tendon. Foot type is associated with morphometry of tendons that control sagittal plane motion of the rearfoot; and the peroneus longus muscle that controls frontal plane motion of the rearfoot. These findings may be related to differences in tendon loading during gait. PMID:23301865

Murley, G S; Tan, J M; Edwards, R M; De Luca, J; Munteanu, S E; Cook, J L

2014-06-01

257

Neurologic complications of distal biceps tendon repair with 1-incision endobutton fixation.  

PubMed

Functional outcomes of biceps tendon rupture may be optimized with operative treatment. We conducted a retrospective study to determine the neurologic complications of using 1-incision Endobutton fixation to repair distal biceps tendon ruptures. Patients with distal biceps tendon ruptures treated with a 1-incision technique and Endobutton fixation were included. The primary outcome measure was frequency of neurologic complications. All 50 patients in the study were men. Mean age was 45 years. Twenty-one patients (42%) had at least 1 complication. Injury to the lateral antebrachial cutaneous nerve (LACN) was the most common (36%). Mean time to diagnosis was 17 days (range, 0 to 40 days). Posterior interosseous, anterior interosseous, and superficial radial nerve palsies each occurred at a 4% rate. Mean follow-up was 133 days. This study involved the largest cohort of patients with distal biceps tendon rupture repaired with Endobutton fixation using a 1-incision technique. The LACN injury rate (36%) was higher than in other studies using the same technique (0% to 22%). Injury rates for other neural structures near the elbow were comparable to those in the literature. PMID:25046193

Carroll, Michael J; DaCambra, Mark P; Hildebrand, Kevin A

2014-07-01

258

Strain-induced Damage Reduces Echo Intensity Changes in Tendon during Loading  

PubMed Central

Tendon functionality is related to its mechanical properties. Tendon damage leads to a reduction in mechanical strength and altered biomechanical behavior, and therefore leads to compromised ability to carry out normal functions such as joint movement and stabilization. Damage can also accumulate in the tissue and lead to failure. A noninvasive method with which to measure such damage potentially could quantify structural compromise from tendon injury and track improvement over time. In this study, tendon mechanics are measured before and after damage is induced by overstretch (strain exceeding the elastic limit of the tissue) using a traditional mechanical test system while ultrasonic echo intensity (average gray scale brightness in a B-mode image) is recorded using clinical ultrasound. The diffuse damage caused by overstretch lowered the stress at a given strain in the tissue and decreased viscoelastic response. Overstretch also lowered echo intensity changes during stress relaxation and cyclic testing. As the input strain during overstretch increased, stress levels and echo intensity changes decreased. Also, viscoelastic parameters and time-dependent echo intensity changes were reduced. PMID:22542220

Duenwald-Kuehl, Sarah; Lakes, Roderic; Vanderby, Ray

2012-01-01

259

Allogenous tendon stem/progenitor cells in silk scaffold for functional shoulder repair.  

PubMed

Tendon stem/progenitor cells (TSPCs) were recently identified within tendon tissues. The aim of this study was to investigate TSPC-seeded knitted silk-collagen sponge scaffold for functional shoulder repair. The multidifferentiation potential, proliferation, and immune properties of TSPCs were investigated in vitro, while the efficacy of TSPC-seeded knitted silk-collagen sponge scaffolds in promoting rotator cuff regeneration was evaluated in vivo within a rabbit model. TSPCs, which exhibited universal stem cell characteristics (i.e., clonogenicity, high proliferative capacity, and multidifferentiation potential), nonimmunogenicity, and immunosuppression, proliferated well on our scaffold in vitro. Implantation of allogenous TSPC-seeded scaffolds within a rabbit rotator cuff injury model did not elicit an immunological reaction, but instead increased fibroblastic cell ingrowth and reduced infiltration of lymphocytes within the implantation sites at 4 and 8 weeks postsurgery. After 12 weeks, the allogenous TSPC-treated group exhibited increased collagen deposition and had better structural and biomechanical properties compared to the control group. This study thus demonstrated that the allogenous TSPC-seeded knitted silk-collagen sponge scaffold enhanced the efficacy of rotator cuff tendon regeneration by differentiating into tenocytes, and by secreting anti-inflammatory cytokines that prevent immunological rejection. Hence, allogenous TSPC-seeded knitted silk-collagen sponge scaffolds can be a clinically useful application for tendon tissue engineering. PMID:22405331

Shen, Weiliang; Chen, Jialin; Yin, Zi; Chen, Xiao; Liu, Huanhuan; Heng, Boon Chin; Chen, Weishan; Ouyang, Hong-Wei

2012-01-01

260

Triceps tendon rupture: an uncommon orthopaedic condition.  

PubMed

Triceps tendon disruption is a rare orthopaedic injury that can lead to poor outcomes if misdiagnosed or managed inappropriately. This case report illustrates the importance of early, precise diagnosis of triceps rupture by clinical and radiological examination with appropriate management. A weightlifter who had fallen while riding his bike presented with pain, swelling around the posterior aspect of the left arm just above the elbow. Physical examination revealed ecchymosis and weakness in elbow extension. A radiograph of the elbow showed a small fleck of bone proximal to the tip of the olecranon. The patient was initially stabilised. Early intervention in the form of primary tendon repair was performed within 3?days and rehabilitation was started. The patient improved significantly to his best possible functional status with Mayo elbow score of 85. Early intervention was the key to better prognosis. PMID:25766435

Bunshah, Jamshed Jal; Raghuwanshi, Sagar; Sharma, Deepak; Pandita, Aakash

2015-01-01

261

Anterior cruciate ligament reconstruction with allograft tendons.  

PubMed

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

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

2003-01-01

262

Quadriceps Tendon Rupture due to Postepileptic Convulsion  

PubMed Central

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

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

2014-01-01

263

Detection and evaluation of failures in high-strength tendon of prestressed concrete bridges by acoustic emission  

Microsoft Academic Search

Failures in high-strength steel tendons of prestressed concrete structures are becoming a serious problem, as the deterioration of structures progresses due to aging. The failure is mainly attributed to the corrosion induced in severe environment as salt attack. Intensive studies were made in a laboratory and fields to investigate an applicability of acoustic emission (AE) technique to detect and locate

S. Yuyama; K. Yokoyama; K. Niitani; M. Ohtsu; T. Uomoto

2007-01-01

264

A Poly(lactic-co-glycolic acid) Knitted Scaffold for Tendon Tissue Engineering: An In Vitro and In Vivo Study  

Microsoft Academic Search

We have designed a composite scaffold for potential use in tendon or ligament tissue engineering. The composite scaffold was made of a cellularized alginate gel that encapsulated a knitted structure. Our hypothesis was that the alginate would act as a cell carrier and deliver cells to the injury site while the knitted structure would provide mechanical strength to the composite

Cdryck Vaquette; Sad Slimani; Cyril J. F. Kahn; Nguyen Tran; Rachid Rahouadj; Xiong Wang

2010-01-01

265

Biomechanical Analysis of Distal Biceps Tendon Repair Methods  

Microsoft Academic Search

Background: The 1-incision and 2-incision techniques are commonly used methods to repair a distal biceps rupture, and they differ in the location of reinsertion of tendon into bone.Hypothesis: The native distal biceps brachii tendon inserts on the posterior-ulnar aspect of the bicipital tuberosity, which functions as a cam, increasing the tendon's moment arm during its principal action of forearm supination.

Jon Henry; Jeff Feinblatt; Christopher C. Kaeding; James Latshaw; Alan Litsky; Roman Sibel; Julie A. Stephens; Grant L. Jones

2007-01-01

266

Low level laser therapy in healing tendon  

NASA Astrophysics Data System (ADS)

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.

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

2005-11-01

267

An artificial tendon with durable muscle interface.  

PubMed

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 eight 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 postsurgery 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 +/- 111.3 N (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

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

2010-02-01

268

An Artificial Tendon with Durable Muscle Interface  

PubMed Central

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 OrthoCouplers 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 298111.3N (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

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

2010-01-01

269

Impact of oestrogen deficiency and aging on tendon: concise review  

PubMed Central

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

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

2014-01-01

270

Biology and augmentation of tendon-bone insertion repair  

PubMed Central

Surgical reattachment of tendon and bone such as in rotator cuff repair, patellar-patella tendon repair and anterior cruciate ligament (ACL) reconstruction often fails due to the failure of regeneration of the specialized tissue ("enthesis") which connects tendon to bone. Tendon-to-bone healing taking place between inhomogenous tissues is a slow process compared to healing within homogenous tissue, such as tendon to tendon or bone to bone healing. Therefore special attention must be paid to augment tendon to bone insertion (TBI) healing. Apart from surgical fixation, biological and biophysical interventions have been studied aiming at regeneration of TBI healing complex, especially the regeneration of interpositioned fibrocartilage and new bone at the healing junction. This paper described the biology and the factors influencing TBI healing using patella-patellar tendon (PPT) healing and tendon graft to bone tunnel healing in ACL reconstruction as examples. Recent development in the improvement of TBI healing and directions for future studies were also reviewed and discussed. PMID:20727196

2010-01-01

271

Smad3 Binds Scleraxis and Mohawk and Regulates Tendon Development  

PubMed Central

TGF? plays a critical role in tendon formation and healing. While its downstream effector Smad3 has been implicated in the healing process, little is known about the role of Smad3 in normal tendon development or tenocyte gene expression. Using mice deficient in Smad3 (Smad3/), we show that Smad3 ablation disrupts normal tendon architecture and has a dramatic impact on normal gene and protein expression during development as well as in mature tendon. In developing and adult tendon, loss of Smad3 results in reduced protein expression of the matrix components Collagen 1 and Tenascin-C. Additionally, when compared to wild type, tendon from adult Smad3/ mice shows a downregulation of key tendon marker genes. Finally, through in vitro work, we have established that Smad3 has the ability to physically interact with the critical transcriptional regulators Scleraxis and Mohawk. Together these results indicate a central role for Smad3 in normal tendon development and in the maintenance of mature tendon. PMID:23653374

Berthet, Ellora; Chen, Carol; Butcher, Kristin; Schneider, Richard A.; Alliston, Tamara; Amirtharajah, Mohana

2014-01-01

272

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

PubMed Central

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

2013-01-01

273

In vivo passive mechanical behaviour of muscle fascicles and tendons in human gastrocnemius muscletendon units  

PubMed Central

Abstract Ultrasound imaging was used to measure the length of muscle fascicles in human gastrocnemius muscles while the muscle was passively lengthened and shortened by moving the ankle. In some subjects the muscle belly buckled at short lengths. When the gastrocnemius muscletendon unit was passively lengthened from its shortest in vivo length by dorsiflexing the ankle, increases in muscletendon length were not initially accompanied by increases in muscle fascicle lengths (fascicle length remained constant), indicating muscle fascicles were slack at short muscletendon lengths. The muscletendon length at which slack is taken up differs among fascicles: some fascicles begin to lengthen at very short muscletendon lengths whereas other fascicles remain slack over a large range of muscletendon lengths. This suggests muscle fascicles are progressively recruited and contribute sequentially to muscletendon stiffness during passive lengthening of the muscletendon unit. Even above their slack lengths muscle fascicles contribute only a small part (tendon length. The contribution of muscle fascicles to muscletendon length increases with muscle length. The novelty of this work is that it reveals a previously unrecognised phenomenon (buckling at short lengths), posits a new mechanism of passive mechanical properties of muscle (recruitment of muscle fascicles), and confirms with high-resolution measurements that the passive compliance of human gastrocnemius muscletendon units is due largely to the tendon. It would be interesting to investigate if adaptations of passive properties of muscles are associated with changes in the distribution of muscle lengths at which fascicles fall slack. PMID:21825027

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

2011-01-01

274

In situ microdialysis in tendon tissue: high levels of glutamate, but not prostaglandin E2 in chronic Achilles tendon pain  

Microsoft Academic Search

This investigation was to our knowledge the first to use the microdialysis technique to study concentrations of substances\\u000a in a human tendon. In four patients (mean age 40.7 years) with a painful nodule in the Achilles tendon (chronic Achilles tendinosis)\\u000a and in five controls (mean age 37.2 years) with normal Achilles tendons (confirmed by ultrasonography) the local concentrations\\u000a of glutamate

H. Alfredson; K. Thorsen; R. Lorentzon

1999-01-01

275

Spontaneous Rupture of the Patellar Tendon and the Contralateral Quadriceps Tendon, Associated with Lupus Erythematosus: Analysis of the Literature  

PubMed Central

Bilateral rupture of the patellar tendon is a rare injury. A case of a 67-year-old man with systemic lupus erythematosus under corticosteroid treatment for the last 10 years, who sustained spontaneous rupture of the patellar tendon and the contralateral quadriceps tendon, is herein presented. The patient was operated bilaterally, had an optimal outcome considering his age and the comorbidities, and was followed up for 24 months. PMID:23198218

Karadimas, Efthimios J.; Kotzamitelos, Dimitrios; Kakagia, Despoina D.; Hatziyiannakis, Athanasios

2011-01-01

276

Recurrent subluxation of the peroneal tendons.  

PubMed

Recurrent peroneal tendon subluxation is an uncommon sports-related injury. The retrofibular groove is formed not by the concavity of the fibula itself, but by a relatively pronounced ridge of collagenous soft tissue blended with the periosteum that extends along the posterolateral lip of the distal fibula. The shape of the groove is primarily determined by this thick fibrocartilagenous periosteal cushion, and not by the bone itself. The superior peroneal retinaculum is extremely variable in width, thickness and insertional patterns. Peroneal tendon subluxation is commonly associated with longitudinal splits in the peroneus brevis tendon and lateral ankle instability. Disruption of the lateral collateral ankle ligaments places considerable strain on the superior peroneal retinaculum. This explains why the two conditions commonly coexist. In recurrent subluxation, patients usually give a history of previous ankle injury, which may have been misdiagnosed as a sprain. An unstable ankle that gives way or is associated with a popping or snapping sensation is another common complaint. The peroneal tendons may actually be seen subluxing anteriorly on the distal fibula during ambulation. The role of imaging has been debated, and the diagnosis and management plan are based on clinical evidence. Conservative management may be attempted in acute dislocations, and can be successful in up to 50% of patients, although there is a trend for operative management in athletes. Recurrent dislocations should be managed surgically. Five basic categories of repair have been described: (i) anatomical reattachment of the retinaculum; (ii) bone-block procedures; (iii) reinforcement of the superior peroneal retinaculum with local tissue transfers; (iv) rerouting the tendons behind the calcaneofibular ligament; and (v) groove deepening procedures. However, it is impossible to determine from the relatively small series which procedure is superior. If an anatomical approach to treating the pathology is utilised, reattachment of the superior retinaculum seems a most appropriate technique. Randomised controlled trials may be the way forward in determining the best surgical management method. However, the relative rarity of the condition and the large number of techniques described make such study difficult. PMID:17004847

Ferran, Nicholas A; Oliva, Francesco; Maffulli, Nicola

2006-01-01

277

Multilayered Electrospun Scaffolds for Tendon Tissue Engineering  

PubMed Central

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

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

2013-01-01

278

Second Harmonic Generation Confocal Microscopy of Collagen Type I from Rat Tendon Cryosections  

PubMed Central

We performed second harmonic generation (SHG) imaging of collagen in rat-tendon cryosections, using femtosecond laser scanning confocal microscopy, both in backscattering and transmission geometries. SHG transmission images of collagen fibers were spatially resolved due to a coherent, directional SHG component. This effect was enhanced with the use of an index-matching fluid (ni = 1.52). The average SHG intensity oscillated with wavelength in the backscattered geometry (isotropic SHG component), whereas the spectral profile was consistent with quasi-phase-matching conditions in transmission geometry (forward propagating, coherent SHG component) around 440 nm (?p = 880 nm). Collagen type I from bovine Achilles tendon was imaged for SHG in the backscattered geometry and its first-order effective nonlinear coefficient was determined (\\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\pagestyle{empty} \\oddsidemargin -1.0in \\begin{document} \\begin{equation*}{\\vert}d_{{\\mathrm{eff}}}{\\vert}\\approx 0.085({\\pm}0.025){\\times}10^{-12}{\\mathrm{mV}}^{-1}\\end{equation*}\\end{document}) by comparison to samples of inorganic materials with known effective nonlinear coefficients (LiNbO3 and LiIO3). The SHG spectral response of collagen type I from bovine Achilles tendon matched that of the rat-tendon cryosections in backscattered geometry. Collagen types I, II, and VI powders (nonfibrous) did not show any detectable SHG, indicating a lack of noncentrosymmetric crystalline structure at the molecular level. The various stages of collagen thermal denaturation were investigated in rat-tendon cryosections using SHG and bright-field imaging. Thermal denaturation resulted in the gradual destruction of the SHG signal. PMID:17130233

Theodossiou, Theodossis A.; Thrasivoulou, Christopher; Ekwobi, Chidi; Becker, David L.

2006-01-01

279

Mechanical and functional properties of implanted freeze-dried flexor tendons.  

PubMed

Tendons harvested from donor dogs were freeze-dried and implanted as free allografts in the paws of recipient experimental animals; the tendons were subsequently tested for mechanical properties, clinical function, and histologic appearance. Free tendon autografts, normal tendons in the operated experimental paw, and normal tendons in the unoperated paw were used as controls and compared with the allografts. Mechanically, the free tendon allografts and autografts were similar. The ultimate strength of the two grafts was statistically the same but significantly less, about one-third, than that of normal tendons. The implanted allografts appeared to be tolerated well by the host and to allow flexor tendon function similar to that allowed by autografts. The histologic appearance of the allograft and autograft tendons was similar at three and six months. Freeze-dried flexor tendon allografting is a satisfactory alternative to free tendon autografting. PMID:6627794

Webster, D A; Werner, F W

1983-11-01

280

Quantifying the deep tendon reflex using varying tendon indentation depths: applications to spasticity.  

PubMed

The deep tendon reflex (DTR) is often utilized to characterize the neuromuscular health of individuals because it is cheap, quick to implement, and requires limited equipment. However, DTR assessment is unreliable and assessor-dependent improve the reliability of the DTR assessment, we devised a novel standardization procedure. Our approach is based on the hypothesis that the neuromuscular state of a muscle changes systematically with respect to the indentation depth of its tendon. We tested the hypothesis by progressively indenting the biceps tendons on each side of nine hemiplegic stroke survivors to different depths, and then superimposing a series of brief controlled taps at each indentation depth to elicit a reflex response. Our results show that there exists a unique indentation depth at which reflex responses are consistently recorded (termed the Reflex Threshold) with increasing amplitude along increasing indentation depth. We further show that the reflex threshold depth is systematically smaller on the affected side of stroke survivors and that it is negatively correlated with the Modified Ashworth Score (VAF 70%). Our procedure also enables measurement of passive mechanical properties at the indentation location. In conclusion, our study shows that controlling for the indentation depth of the tendon of a muscle alters its reflex response predictably. Our novel device and method could be used to estimate neuromuscular changes in muscle (e.g., spasticity). Although some refinement is needed, this method opens the door to more reliable quantification of the DTR. PMID:24621852

Chardon, Matthieu K; Rymer, W Zev; Suresh, Nina L

2014-03-01

281

Achilles tendon rupture following coblation for insertional Achilles tendinosis.  

PubMed

Radiofrequency microdebridement for Achilles tendinosis is a relatively new technique. We report a case of Achilles tendon rupture in a patient eight weeks after coblation for his right insertional Achilles tendinosis. We believe that this is the first reported case of Achilles tendon rupture following this new treatment of radiofrequency microdebridement for chronic Achilles tendinosis. PMID:20307450

Akhtar, M A; Montgomery, H; Shenolikar, A

2009-03-01

282

Achilles tendon rupture and sciatica: a possible correlation  

Microsoft Academic Search

The association between Achilles tendon rupture and sciatica was investigated by questionnaire in 138 patients who underwent repair of an Achilles tendon rupture, and in a group of individuals nominated by the patients, matched for age, sex, and occupation. A total of 102 patients (74%) and 128 peer nominated controls (71%) replied to the questionnaire. Of the 102 respondent patients,

N. Maffulli; A. S. Irwin; M. G. Kenward; F. Smith; R. W. Porter

1998-01-01

283

Abductor tendon tears of the hip: evaluation and management.  

PubMed

The gluteus medius and minimus muscle-tendon complex is crucial for gait and stability in the hip joint. There are three clinical presentations of abductor tendon tears. Degenerative or traumatic tears of the hip abductor tendons, so-called rotator cuff tears of the hip, are seen in older patients with intractable lateral hip pain and weakness but without arthritis of the hip joint. The second type of tear may be relatively asymptomatic. It is often seen in patients undergoing arthroplasty for femoral neck fracture or elective total hip arthroplasty (THA) for osteoarthritis. The third type of abductor tendon dysfunction occurs with avulsion or failure of repair following THA performed through the anterolateral approach. Abductor tendon tear should be confirmed on MRI. When nonsurgical management is unsuccessful, open repair of the tendons with transosseous sutures is recommended. Good pain relief has been reported following endoscopic repair. Abductor tendon repair has had inconsistent results in persons with avulsion following THA. Reconstruction with a gluteus maximus muscle flap or Achilles tendon allograft has provided promising short-term results in small series. PMID:21724917

Lachiewicz, Paul F

2011-07-01

284

Physiological Loading of Tendons Induces Scleraxis Expression in Epitenon Fibroblasts  

PubMed Central

Scleraxis is a bHLH transcription factor that plays a central role in promoting fibroblast proliferation and matrix synthesis during the embryonic development of tendons. Mice with a targeted inactivation of scleraxis (Scx?/?) fail to properly form limb tendons, but the role that scleraxis has in regulating the growth and adaptation of tendons of adult organisms is unknown. To determine if scleraxis expression changes in response to a physiological growth stimulus to tendons, we subjected adult mice that express GFP under the control of the scleraxis promoter (ScxGFP) to a six week treadmill training program designed to induce adaptive growth in Achilles tendons. Age matched sedentary ScxGFP mice were used as controls. Scleraxis expression was sparsely observed in the epitenon region of sedentary mice, but in response to treadmill training, scleraxis was robustly expressed in fibroblasts that appeared to be emerging from the epitenon and migrating into the superficial regions of tendon fascicles. Treadmill training also led to an increase in scleraxis, tenomodulin, and type I collagen gene expression as measured by qPCR. These results suggest that in addition to regulating the embryonic formation of limb tendons, scleraxis also appears to play an important role in the adaptation of adult tendons to physiological loading. PMID:21913219

Mendias, Christopher L; Gumucio, Jonathan P; Bakhurin, Konstantin I; Lynch, Evan B; Brooks, Susan V

2011-01-01

285

MAC-EYE: a Tendon Driven Fully Embedded Robot Eye  

E-print Network

MAC-EYE: a Tendon Driven Fully Embedded Robot Eye Dario Biamino, Giorgio Cannata, Marco Maggiali the possibility of designing a robot eye with kinematics and actuation similar to those of the human eye. In particular, we tried to exploit the spherical shape of the eye and to study the feasibility of a tendon based

Cannata, Giorgio

286

Achilles tendon biomechanics in response to acute intense exercise.  

PubMed

Achilles tendinopathy is a common disorder and is more prevalent in men. Although differences in tendon mechanics between men and women have been reported, understanding of tendon mechanics in young active people is limited. Moreover, there is limited understanding of changes in tendon mechanics in response to acute exercise. Our purpose was to compare Achilles tendon mechanics in active young adult men and women at rest and after light and strenuous activity in the form of repeated jumping with an added load. Participants consisted of 17 men and 14 women (18-30 years) who were classified as being at least moderately physically active as defined by the International Physical Activity Questionnaire. Tendon force/elongation measures were obtained during an isometric plantarflexion contraction on an isokinetic dynamometer with simultaneous ultrasound imaging of the Achilles tendon approximate to the soleus myotendinous junction. Data were collected at rest, after a 10-minute treadmill walk, and after a fatigue protocol of 100 toe jumps performed in a Smith machine, with a load equaling 20% of body mass. We found greater tendon elongation, decreased stiffness, and lower Young's modulus only in women after the jumping exercise. Force and stress were not different between groups but decreased subsequent to the jumping exercise bout. In general, women had greater elongation and strain, less stiffness, and a lower Young's modulus during plantarflexor contraction. These data demonstrate differences in tendon mechanics between men and women and suggest a potential protective mechanism explaining the lower incidence of Achilles tendinopathy in women. PMID:24552794

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

2014-05-01

287

Management of flexor tendon sheath ganglions: A cost analysis  

Microsoft Academic Search

The purpose of this study was to determine success rates of 1 or more aspirations on flexor tendon sheath ganglions compared with surgical excision and to determine what treatment method is most cost-effective. Data were collected from documented history and physical examinations, operative reports, billing records, and telephone interviews. Of the 259 patients coded as having flexor tendon sheath ganglions,

James G. Bittner IV; Richard Kang; Peter J. Stern

2002-01-01

288

A study on the vascular supply of the supraspinatus tendon  

Microsoft Academic Search

Summary The vascular supply of the rotator cuff in 22 adult shoulders was studied by way of mixture infusion of gelatin and India ink and vascular cast, in combination with Scanning Electronic Microscopy of the vascular pattern in the supraspinatus tendon. It was found that the vessels of the supraspinatus tendon mainly derive from the anterior circumflex humeral and suprascapular

S-C Ling; C-F Chen; R-X Wan

1990-01-01

289

Finite element modeling of concrete beams prestressed with external tendons  

Microsoft Academic Search

In this study, a numerical model based on the finite element method incorporating an arc-length solution algorithm for materially and geometrically nonlinear analysis of concrete beams prestressed with external tendons is established. The second-order effects are taken into account. The effects of external tendons are expressed by equivalent nodal loads of the beam element and therefore analysis of externally prestressed

Tie-jiong Lou; Yi-qiang Xiang

2006-01-01

290

Continuum model of tendon pathology where are we now?  

PubMed Central

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

McCreesh, Karen; Lewis, Jeremy

2013-01-01

291

Torque Control of Underactuated Tendon-driven Robotic Fingers  

NASA Technical Reports Server (NTRS)

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.

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

292

Surgical treatment of peroneal tendon tears.  

PubMed

The focus of this article is the diagnosis and treatment of peroneal tendon tears. The article first describes mechanisms of injuries resulting in peroneal brevis and longus tears. Associated pathologies, such as ankle instability, hindfoot varus, hypertrophied peroneal tubercle, are discussed. Following sections on diagnosis and conservative treatment, the article describes operative treatment for isolated peroneus brevis tear, isolated peroneus longus tear, and tears of both the peroneus longus and brevis. The authors also discuss hamstring allograft reconstruction, the silicone rod technique, flexor digitorum longus transfer to the peroneus brevis, and treatment of associated pathology. PMID:17996622

Squires, Natalie; Myerson, Mark S; Gamba, Cesar

2007-12-01

293

Mechanical model of a single tendon finger  

NASA Astrophysics Data System (ADS)

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.

Rossi, Cesare; Savino, Sergio

2013-10-01

294

Vascular Endothelial Growth Factor-111 (VEGF-111) and tendon healing: preliminary results in a rat model of tendon injury  

PubMed Central

Summary Tendon lesions are among the most frequent musculoskeletal pathologies. Vascular endothelial growth factor (VEGF) is known to regulate angiogenesis. VEGF-111, a biologically active and proteolysis-resistant splice variant of this family, was recently identified. This study aimed at evaluating whether VEGF-111 could have a therapeutic interest in tendon pathologies. Surgical section of one Achilles tendon of rats was performed before a local injection of either saline or VEGF-111. After 5, 15 and 30 days, the Achilles tendons of 10 rats of both groups were sampled and submitted to a biomechanical tensile test. The force necessary to induce tendon rupture was greater for tendons of the VEGF-111 group (p<0.05) while the section areas of the tendons were similar. The mechanical stress was similar at 5 and 15 days in the both groups but was improved for the VEGF-111 group at day 30 (p <0.001). No difference was observed in the mRNA expression of collagen III, tenomodulin and MMP-9. In conclusion, we observed that a local injection of VEGF-111 improves the early phases of the healing process of rat tendons after a surgical section. Further confirmatory experimentations are needed to consolidate our results. PMID:24932443

Kaux, Jean-Franois; Janssen, Lauriane; Drion, Pierre; Nusgens, Betty; Libertiaux, Vincent; Pascon, Frdric; Heyeres, Antoine; Hoffmann, Audrey; Lambert, Charles; Le Goff, Caroline; Denol, Vincent; Defraigne, Jean-Olivier; Rickert, Markus; Crielaard, Jean-Michel; Colige, Alain

2014-01-01

295

Is there an association between an absence of palmaris longus tendon and an absence of plantaris tendon?  

Microsoft Academic Search

Tendon grafts are frequently required, particularly in reconstructive hand surgery. Palmaris longus has been the commonest donor tendon but its absence is quoted in the literature to be about 13%. Plantaris is then often sought as a substitute, and although there is less documentation about its incidence of absence, it appears to be not present in about 7% of cadavers.

A. L. H. Moss

1988-01-01

296

Altered Fate of Tendon-Derived Stem Cells Isolated from a Failed Tendon-Healing Animal Model of Tendinopathy  

PubMed Central

We hypothesized that altered fate of tendon-derived stem cells (TDSCs) might contribute to chondro-ossification and failed healing in the collagenase-induced (CI) tendon injury model. This study aimed to compare the yield, proliferative capacity, immunophenotypes, senescence, and differentiation potential of TDSCs isolated from healthy (HT) and CI tendons. TDSCs were isolated from CI and healthy Sprague-Dawley rat patellar tendons. The yield, proliferative capacity, immunophenotypes, and senescence of TDSCs (CI) and TDSCs (HT) were compared by colony-forming unit assay, BrdU assay, flow cytometry, and ?-galactosidase activity assay, respectively. Their osteogenic and chondrogenic differentiation potentials and mRNA expression of tendon-related markers were compared using standard assays. More TDSCs, which showed a lower proliferative potential and a higher cellular senescence were present in the CI patellar tendons compared to HT tendons. There was a higher alkaline phosphatase activity and mineralization in TDSCs (CI) in both basal and osteogenic media. More chondrocyte-like cells and higher proteoglycan deposition, Sox9 and collagen type II expression were observed in TDSCs (CI) pellets upon chondrogenic induction. There was a higher protein expression of Sox9, but a lower mRNA expression of Col1a1, Scx, and Tnmd in TDSCs (CI) in a basal medium. In conclusion, TDSCs (CI) showed altered fate, a higher cellular senescence, but a lower proliferative capacity compared to TDSCs (HT), which might contribute to pathological chondro-ossification and failed tendon healing in this animal model. PMID:23106341

Rui, Yun Feng; Wong, Yin Mei; Tan, Qi; Chan, Kai Ming

2013-01-01

297

Scx-Transduced Tendon-Derived Stem Cells (TDSCs) Promoted Better Tendon Repair Compared to Mock-Transduced Cells in a Rat Patellar Tendon Window Injury Model  

PubMed Central

We hypothesized that the transplantation of Scx-transduced tendon-derived stem cells (TDSCs) promoted better tendon repair compared to the transplantation of mock-transduced cells. This study thus aimed to investigate the effect of Scx transduction on the expression of lineage markers in TDSCs and the effect of the resulting cell line in the promotion of tendon repair. Rat non-GFP or GFP-TDSCs were transduced with Scx or empty lentiviral vector (Mock) and selected by blasticidin. The mRNA expressions of Scx and different lineage markers were examined by qRT-PCR. The effect of the transplantation of GFP-TDSC-Scx on tendon repair was then tested in a rat unilateral patellar tendon window injury model. The transplantation of GFP-TDSC-Mock and scaffold-only served as controls. At week 2, 4 and 8 post-transplantation, the repaired patellar tendon was harvested for ex vivo fluorescent imaging, vivaCT imaging, histology, immunohistochemistry and biomechanical test. GFP-TDSC-Scx consistently showed higher expressions of most of tendon- and cartilage- related markers compared to the GFP-TDSC-Mock. However, the effect of Scx transduction on the expressions of bone-related markers was inconclusive. The transplanted GFP-TDSCs could be detected in the window wound at week 2 but not at week 4. Ectopic mineralization was detected in some samples at week 8 but there was no difference among different groups. The GFP-TDSC-Scx group only statistically significantly improved tendon repair histologically and biomechanically compared to the Scaffold-only group and the GFP-TDSC-Mock group at the early stage of tendon repair. There was significant higher expression of collagen type I in the window wound in the GFP-TDSC-Scx group compared to the other two groups at week 2. The transplantation of GFP-TDSC-Scx promoted healing at the early stage of tendon repair in a rat patellar tendon window injury model. PMID:24831949

Lee, Yuk Wa; Wong, Yin Mei

2014-01-01

298

Biomechanical properties of Achilles tendon repair augmented with a bioadhesive-coated scaffold  

Microsoft Academic Search

The Achilles tendon is the most frequently ruptured tendon. Both acute and chronic (neglected) tendon ruptures can dramatically affect a patient's quality of life, and require a prolonged period of recovery before return to pre-injury activity levels. This paper describes the use of an adhesive-coated biologic scaffold to augment primary suture repair of transected Achilles tendons. The adhesive portion consisted

Michael Brodie; Laura Vollenweider; John L. Murphy; Fangmin Xu; Arinne Lyman; William D. Lew; Bruce P. Lee

2011-01-01

299

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

PubMed Central

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

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

2014-01-01

300

Ruptures of the distal biceps tendon.  

PubMed

Distal biceps ruptures occur most commonly in middle-aged males and result from eccentric contraction of the biceps tendon. The injury typically presents with pain and a tearing sensation in the antecubital fossa with resultant weakness in flexion and supination strength. Physical exam maneuvers and diagnostic imaging aid in determining the diagnosis. Nonoperative management is reserved for elderly, low demand patients, while operative intervention is generally pursued for younger patients and can consist of nonanatomic repair to the brachialis or anatomic repair to the radial tuberosity. Anatomic repair through a one-incision or two-incision approach is commonplace, while the nonanatomic repairs are rarely performed. No clear advantage exists in operative management with a one-incision versus two-incision techniques. Chronic ruptures present a more difficult situation, and allograft augmentation is often necessary. Common complications after repair include transient nerve palsy, which often resolves, and heterotopic ossification. Despite these possible complications, most studies suggest that better patient outcomes are obtained with operative, anatomic reattachment of the distal biceps tendon. PMID:25150334

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

2014-01-01

301

Morphological studies of bone and tendon.  

PubMed

The Soviet biosatellite COSMOS 2044 carried adult rats on a spaceflight that lasted 13.8 days and was intended to repeat animal studies carried out on COSMOS 1887. Skeletal tissue and tendon from animals flown on COSMOS 2044 were studied by light and electron microscopy, histochemistry, and morphometric techniques. Studies were confined to the bone cells and vasculature from the weight-bearing tibias. Results indicated that vascular changes at the periosteal and subperiosteal region of the tibia were not apparent by light microscopy or histochemistry. However, electron microscopy indicated that vascular inclusions were present in bone samples from the flight animals. A unique combination of microscopy and histochemical techniques indicated that the endosteal osteoblasts from this same mid-diaphyseal region demonstrated a slight (but not statistically significant) reduction in bone cell activity. Electron-microscopic studies of the tendons from metatarsal bones showed a collagen fibril disorganization as a result of spaceflight. Thus changes described for COSMOS 1887 were present in COSMOS 2044, but the changes ascribed to spaceflight were not as evident. PMID:1526935

Doty, S B; Morey-Holton, E R; Durnova, G N; Kaplansky, A S

1992-08-01

302

Surgical considerations for the neglected or chronic Achilles tendon rupture: a combined technique for reconstruction.  

PubMed

The Achilles tendon is among the most commonly injured tendons in the human body. The most common reason for delayed treatment is a missed diagnosis or a deficiency in presentation. The neglected or chronically ruptured Achilles tendon presents a unique treatment challenge. The surgical approach varies greatly depending on the extent of degeneration and the resultant gap between the opposing tendon ends. Most surgeons have recommended the use of a tendon transfer or augmentation to strengthen the Achilles tendon repair. The following technique uses a flexor hallucis longus tendon transfer with gastrocnemius aponeurosis turndown flap augmentation. This technique has been commonly performed by us with success. PMID:24269103

Peterson, Kyle S; Hentges, Matthew J; Catanzariti, Alan R; Mendicino, Michael R; Mendicino, Robert W

2014-01-01

303

Chiasma crurale: intersection of the tibialis posterior and flexor digitorum longus tendons above the ankle. Magnetic resonance imaginganatomic correlation in cadavers  

PubMed Central

Purpose To determine the precise anatomy and magnetic resonance (MR) imaging appearance of the chiasma crurale in cadavers, paying special attention to degenerative changes Material and methods Twelve fresh human ankles were harvested from 11 nonembalmed cadavers (mean age at death 77years) and used according to institutional guidelines. MR imaging and MR tenography were used to investigate the anatomy of the chiasma crurale using proton density-weighted sequences. The gross anatomy of the chiasma crurale was evaluated and compared to the MR imaging findings. Histology was used to elucidate further the structure of the chiasma crurale. Results Above the chiasma, five specimens had a small amount of fat tissue between the tibialis posterior and flexor digitorum longus tendon. In all specimens both tendons had a sheath below the chiasma but not above it. At the central portion of the chiasma there was no soft tissue between the tendons, except in two specimens that showed an anatomic variant consisting of a thick septum connecting the tibial periosteum and the deep transverse fascia of the leg. In MR images, eight specimens showed what were believed to be degenerative changes in the tendons at the level of the chiasma. However, during gross inspection and histologic analysis of the specimens, there was no tendon degeneration visible. Conclusion At the central portion of the chiasma, there is no tissue between the tibialis posterior and flexor digitorum longus tendons unless there is an anatomic variant. At the chiasma crurale, areas with irregular tendon surfaces are normal findings and are not associated with tendon degeneration (fraying). PMID:19876626

Gheno, Ramon; Nico, Marcelo A. C.; Haghighi, Parviz; Trudell, Debra J.; Resnick, Donald

2009-01-01

304

Tendon-to-bone healing using autologous bone marrow-derived mesenchymal stem cells in ACL reconstruction without a tibial bone tunnel-A histological study-  

PubMed Central

Summary Background: after anterior cruciate ligament (ACL) reconstruction, it is necessary to integrate free tendon graft biologically to the bone. In the present study, to verify whether a structure identical to the normal ligament-bone insertion could be regenerated at the tendon-bone interface without bone tunnel, we designed ACL reconstruction model without a tibial bone tunnel. Moreover, to enhance the integration process in this model, bone marrow-derived mesenchymal stem cells (bMSCs) were transplanted, and histological changes investigated. Our first hypothesis was that the grafted tendon would be anchored at part of the tendon-bone interface even if a bone tunnel was not created. Second hypothesis was that application of bMSCs at the tendon-bone interface would yield results histologically superior to those in controls. Methods: bilateral ACL reconstruction using our originally designed method was performed. Autologous bMSCs with the carrier were transplanted between the bottom of the grafted tendon and the bone pit of the tibia in the experimental limb, whereas the control limb received the carrier only. At 4 and 8 weeks after the operation, histological comparison between bMSCs and the control group was carried out. Results/Conclusions: even in our present ACL reconstruction model without a tibial bone tunnel, integration via chondroid tissue was seen at part of the tendon-bone interface. However, there were no appreciable differences between the groups. In ACL reconstruction, to enhance the tendon-bone integration without a bone tunnel would lead to save the graft length and prevent from bone tunnel complications (ex. Bone-tunnel enlargement after surgery). PMID:25332936

Kanazawa, Tomonoshin; Soejima, Takashi; Noguchi, Kouji; Tabuchi, Kousuke; Noyama, Megumi; Nakamura, Kei-ichiro; Shiba, Naoto

2014-01-01

305

Tension Control for Tendon Mechanisms by Compensation of Nonlinear Spring Characteristic Equation Error  

NASA Astrophysics Data System (ADS)

Versatility and adherence to safety norms that are required of manipulators used in a human environment can be achieved by using tendon mechanisms that employ nonlinear springs. The nonlinear spring used in this paper is stiffness adjustable tendon (SAT), which has advantages such as it is light weight, low cost, and has a simple structure. However, precise tension control of SAT cannot be achieved by conventional methods based on a spring characteristic equation because of the SAT's hysteresis characteristics. Therefore, we propose a tension control method for nonlinear springs whose precise equation is difficult to obtain, such as SAT; this method is realized by using a disturbance observer and a reaction force observer. Experimental results validate the proposed method.

Haiya, Kazuo; Komada, Satoshi; Hirai, Junji

306

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

PubMed Central

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

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

2009-01-01

307

A mechanistic study for strain rate sensitivity of rabbit patellar tendon.  

PubMed

The ultrastructural mechanism for strain rate sensitivity of collagenous tissue has not been well studied at the collagen fibril level. Our objective is to reveal the mechanistic contribution of tendon's key structural component to strain rate sensitivity. We have investigated the structure of the collagen fibril undergoing tension at different strain rates. Tendon fascicles were pulled and fixed within the linear region (12% local tissue strain) at multiple strain rates. Although samples were pulled to the same percent elongation, the fibrils were noticed to elongate differently, increasing with strain rate. For the 0.1, 10, and 70%/s strain rates, there were 1.843.6%, 5.51.9%, and 7.032.2% elongations (meanS.D.), respectively. We concluded that the collagen fibrils underwent significantly greater recruitment (fibril strain relative to global tissue strain) at higher strain rates. A better understanding of tendon mechanisms at lower hierarchical levels would help establish a basis for future development of constitutive models and assist in tissue replacement design. PMID:20678772

Clemmer, John; Liao, Jun; Davis, Debbie; Horstemeyer, Mark F; Williams, Lakiesha N

2010-10-19

308

Changes in collagen fibril pattern and adhesion force with collagenase-induced injury in rat Achilles tendon observed via AFM.  

PubMed

The Achilles tendon consists mainly of type I collagen fibers that contain collagen fibrils. When the Achilles tendon is injured, it is inflamed. The collagenase-induced model has been widely used to study tendinitis. The major advantages of atomic force microscopy (AFM) over conventional optical and electron microscopy for bio-imaging include its non-requirement of a special coating and vacuum, and its capability to perform imaging in all environments. AFM force-distance measurements have become a fundamental tool in the fields of surface chemistry, biochemistry and materials science. Therefore, the changes in the ultrastructure and adhesion force of the collagen fibrils on the Achilles tendons of rats with Achilles tendinitis were observed using AFM. The changes in the structure of the Achilles tendons were evaluated based on the diameter and D-banding of the collagen fibrils. Collagenase-induced Achilles tendinitis was induced with the injection of 30 microl crude collagenase into 7-week-old male Sprague-Dawley rats. The animals were each sacrificed on the first, second, third, fifth and seventh day after the collagenase injection. The normal and injured Achilles tendons were fixed in 4% buffered formalin and dehydrated with increasing concentrations of ethanol. AFM was performed using the non-contact mode at the resolution of 512 x 512 pixels, with a scan speed of 0.8 line/sec. The adhesion force was measured via the force-distance curve that resulted from the interactions between the AFM tip and the collagen fibril sample using the contact mode. The diameter of the collagen fibrils in the Achilles tendons significantly decreased (p < 0.05) after the collagenase injection, and the pattern of the D-banding of the collagen fibrils was similar to that of the diameter changes. The adhesion force decreased until the fifth day after the collagenase injection, but increased on the seventh day after the collagenase injection (p < 0.0001). PMID:21446543

Lee, Gi-Ja; Choi, Samjin; Chon, Jinmann; Yoo, Seungdon; Cho, Ilsung; Park, Hun-Kuk

2011-01-01

309

Current Concepts in Examination and Treatment of Elbow Tendon Injury  

PubMed Central

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

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

2013-01-01

310

Successful management of bilateral patellar tendon rupture in a dog.  

PubMed

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

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

2008-01-01

311

Transcriptomic analysis of mouse limb tendon cells during development.  

PubMed

The molecular signals driving tendon development are not fully identified. We have undertaken a transcriptome analysis of mouse limb tendon cells that were isolated at different stages of development based on scleraxis (Scx) expression. Microarray comparisons allowed us to establish a list of genes regulated in tendon cells during mouse limb development. Bioinformatics analysis of the tendon transcriptome showed that the two most strongly modified signalling pathways were TGF-? and MAPK. TGF-?/SMAD2/3 gain- and loss-of-function experiments in mouse limb explants and mesenchymal stem cells showed that TGF-? signalling was sufficient and required via SMAD2/3 to drive mouse mesodermal stem cells towards the tendon lineage ex vivo and in vitro. TGF-? was also sufficient for tendon gene expression in late limb explants during tendon differentiation. FGF does not have a tenogenic effect and the inhibition of the ERK MAPK signalling pathway was sufficient to activate Scx in mouse limb mesodermal progenitors and mesenchymal stem cells. PMID:25249460

Havis, Emmanuelle; Bonnin, Marie-Ange; Olivera-Martinez, Isabel; Nazaret, Nicolas; Ruggiu, Mathilde; Weibel, Jennifer; Durand, Charles; Guerquin, Marie-Justine; Bonod-Bidaud, Christelle; Ruggiero, Florence; Schweitzer, Ronen; Duprez, Delphine

2014-10-01

312

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

NASA Astrophysics Data System (ADS)

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.

Taha, Mahmoud Reda

313

Spatial variations in Achilles tendon shear wave speed.  

PubMed

Supersonic shear imaging (SSI) is an ultrasound imaging modality that can provide insight into tissue mechanics by measuring shear wave propagation speed, a property that depends on tissue elasticity. SSI has previously been used to characterize the increase in Achilles tendon shear wave speed that occurs with loading, an effect attributable to the strain-stiffening behavior of the tissue. However, little is known about how shear wave speed varies spatially, which is important, given the anatomical variation that occurs between the calcaneus insertion and the gastrocnemius musculotendon junction. The purpose of this study was to investigate spatial variations in shear wave speed along medial and lateral paths of the Achilles tendon for three different ankle postures: resting ankle angle (R, i.e. neutral), plantarflexed (P; R - 15), and dorsiflexed (D; R+15). We observed significant spatial and posture variations in tendon shear wave speed in ten healthy young adults. Shear wave speeds in the Achilles free tendon averaged 12 1.2m/s in a resting position, but decreased to 7.2 1.8m/s with passive plantarflexion. Distal tendon shear wave speeds often reached the maximum tracking limit (16.3m/s) of the system when the ankle was in the passively dorsiflexed posture (+15 from R). At a fixed posture, shear wave speeds decreased significantly from the free tendon to the gastrocnemius musculotendon junction, with slightly higher speeds measured on the medial side than on the lateral side. Shear wave speeds were only weakly correlated with the thickness and depth of the tendon, suggesting that the distal-to-proximal variations may reflect greater compliance in the aponeurosis relative to the free tendon. The results highlight the importance of considering both limb posture and transducer positioning when using SSI for biomechanical and clinical assessments of the Achilles tendon. PMID:24933528

DeWall, Ryan J; Slane, Laura C; Lee, Kenneth S; Thelen, Darryl G

2014-08-22

314

Connecting muscles to tendons: tendons and musculoskeletal development in flies and vertebrates  

PubMed Central

The formation of the musculoskeletal system represents an intricate process of tissue assembly involving heterotypic inductive interactions between tendons, muscles and cartilage. An essential component of all musculoskeletal systems is the anchoring of the force-generating muscles to the solid support of the organism: the skeleton in vertebrates and the exoskeleton in invertebrates. Here, we discuss recent findings that illuminate musculoskeletal assembly in the vertebrate embryo, findings that emphasize the reciprocal interactions between the forming tendons, muscle and cartilage tissues. We also compare these events with those of the corresponding system in the Drosophila embryo, highlighting distinct and common pathways that promote efficient locomotion while preserving the form of the organism. PMID:20699295

Schweitzer, Ronen; Zelzer, Elazar; Volk, Talila

2010-01-01

315

Posterior tibial tendon dysfunction in the adult: current concepts.  

PubMed

The management of posterior tibial tendon dysfunction in adults has evolved substantially, and controversy persists regarding a specific recommended algorithm for treatment. The current focus is on early diagnosis and treatment of this disorder with joint-sparing surgeries, such as corrective osteotomies and tendon transfers, when nonsurgical modalities have been exhausted. It is helpful to be familiar with the pertinent pathophysiology and diagnostic pearls associated with posterior tibial tendon dysfunction, its treatment options, pertinent literature, and technique tips for the procedures currently being used. PMID:25745927

Stein, Benjamin E; Schon, Lew C

2015-01-01

316

Arthroscopic Recognition and Repair of the Torn Subscapularis Tendon  

PubMed Central

Although the subscapularis has historically received less attention than posterosuperior rotator cuff tears, repair of a torn subscapularis tendon is critically important to restoring anatomy and achieving the best functional outcome possible. Arthroscopic repair begins with proper recognition of the tear. A systematic approach can then be used to arthroscopically repair all types of subscapularis tendon tears, from partial tears to full-thickness tears, as well as those which are retracted and have adhesions medially. Subscapularis footprint restoration can be accomplished with a variety of repair techniques that must be matched to the extent of the tear and mobility of the tendon. PMID:24400185

Denard, Patrick J.; Burkhart, Stephen S.

2013-01-01

317

Repair of severe muscle belly lacerations using a tendon graft.  

PubMed

Fourteen patients with 58 severe forearm muscle belly lacerations had muscle repair using tendon grafts. At mean follow-up of 14 months, results of manual muscle testing (N = 58) were: grade 5, 42%, grade 4, 14%, grade 3, 9%, grade 2, 9%, grade 1, 12%, and grade 0, 15%. Mean grip strength of the injured extremity, in pounds per square inch, was 33.5 compared with 83.4 on the noninjured side. Tendon excursion and joint mobility were maintained, and there were no postoperative complications. Tendon grafting of severe muscle lacerations is an effective method to overcome extensive defects. PMID:3295003

Botte, M J; Gelberman, R H; Smith, D G; Silver, M A; Gellman, H

1987-05-01

318

Tendon transfers in the treatment of the adult flatfoot.  

PubMed

Tendon transfers are critical to successful surgical correction of adult flexible flatfoot deformity and may be beneficial in correcting rigid deformities as well. Patients with refractory stageI and II deformities often require selective osteotomies in addition to tendon transfer. Patients with stageIII and IV deformities typically require hindfoot arthrodesis. One of several tendons can be used for transfer based on surgeon's preference. Flexor digitorum longus (FDL) and flexor hallucis longus (FHL) transfers have been shown to have good results. A peroneus brevis transfer is typically used to supplement small FDL or FHL transfer donors or in revision cases. PMID:24548507

Backus, Jonathon D; McCormick, Jeremy J

2014-03-01

319

Stapedius tendon reconstruction during stapedotomy: technique and results.  

PubMed

During surgery for otosclerosis, it is common for the surgeon to cut the stapedius tendon. Even without reconstruction of the tendon, the results of this kind of surgery are particularly satisfactory. The stapedial reflex is more important for improving intelligibility of speech in the presence of background noise than for protection against hazardous levels of noise. An intact stapedial reflex improves ones ability to follow speech in the presence of background noise. This report will present a technique to reconstruct the stapedius tendon, along with the results obtained when adding this procedure to stapedotomy surgery. PMID:9127525

Causse, J B; Vincent, R; Michat, M; Gherini, S

1997-04-01

320

Surgical treatment options for patella tendon rupture, part II: chronic.  

PubMed

Patella tendon rupture is a debilitating injury that often occurs in the setting of preexisting tendon degeneration. Prompt diagnosis and treatment is essential to prevent retraction of the patella with subsequent adhesions and quadriceps contractures. In the setting of a chronic rupture, augmentation with hamstring tendons or allograft reconstruction generally is necessary. Patients who undergo delayed repair are at risk for a compromised result secondary to loss of full knee flexion and decreased quadriceps strength, although a functional extensor mechanism is likely to be reestablished. Overall the results of chronic repair are less satisfactory than the acute repair, but still provide an extensor mechanism for the patient and thus provide function. PMID:16119741

Greis, Patrick E; Lahav, Amit; Holmstrom, Michael C

2005-08-01

321

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

PubMed Central

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

Pietschmann, Matthias F.; Glecyz, Mehmet F.; Ficklscherer, Andreas; Jansson, Volkmar; Mller, Peter E.

2014-01-01

322

Minimally invasive surgery for Achilles tendon pathologies  

PubMed Central

Minimally invasive trauma and orthopedic surgery is increasingly common, though technically demanding. Its use for pathologies of the Achilles tendon (AT) hold the promise to allow faster recovery times, shorter hospital stays, and improved functional outcomes when compared to traditional open procedures, which can lead to difficulty with wound healing because of the tenuous blood supply and increased chance of wound breakdown and infection. We present the recent advances in the field of minimally invasive AT surgery for tendinopathy, acute ruptures, chronic tears, and chronic avulsions of the AT. In our hands, minimally invasive surgery has provided similar results to those obtained with open surgery, with decreased perioperative morbidity, decreased duration of hospital stay, and reduced costs. So far, the studies on minimally invasive orthopedic techniques are of moderate scientific quality with short follow-up periods. Multicenter studies with longer follow-up are needed to justify the long-term advantages of these techniques over traditional ones. PMID:24198547

Maffulli, Nicola; Longo, Umile Giuseppe; Spiezia, Filippo; Denaro, Vincenzo

2010-01-01

323

Localized pulsed magnetic fields for tendonitis therapy.  

PubMed

Energy medicine has existed for centuries in some parts of the world, but in recent years, western health care practitioners have taken a heightened interest in these therapies. Treatment by use of pulsed magnetic fields (PMF) is currently being explored in both chronic and inflammatory diseases such as cancer, epilepsy, psoriasis, rheumatoid arthritis, and tendinitis. In the U.S., PMFs have already been approved for use in treatment of bone fractures in humans and clinical trials have been conducted for lower back pain. This study presents a summary of the therapeutic potential of a localized PMF treatment for tendinitis using the Softpulse III system. This system has been used to accelerate wound healing and soft tissue swelling. It generates a specific PMF that induces an electrical field within the tendon. This induced electrical field is thought to influence the healing process by affecting the inflammatory cells that line the tendon sheath. In this study, we have used an established model of tendinitis along with a validated method for appraising edema and gait (Achilles' Functional Index), to test the hypothesis that the proposed PMF signal is effective in reducing the indicators of acute tendinitis injury. These experiments were approved by the Institutional Animal Care and Use Committee. Our findings suggest a role for the treatment of soft tissue injury using the Softpulse III therapeutic device. The symbolic stand point of PMF treatments is to push the need for a revolutionary leap, from the more dominant pharmaceutical and surgical interventions, to the advanced applications of non-invasive therapies that would minimize the medicinal risk of side effects, and eliminate the risk of complicated drug interactions. PMID:16817646

Owegi, Robert; Johnson, Mary T

2006-01-01

324

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

NASA Astrophysics Data System (ADS)

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

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

325

Histological and molecular analysis of the biceps tendon long head post-tenotomy.  

PubMed

Tendinopathy is a vexing clinical problem as its onset and development is often asymptomatic and unrecognized until tendon rupture. While extensively studied in the rotator cuff, Achilles, and patellar tendons, no study to date has examined the histological and molecular characteristics of the tendinopathic biceps long-head (LHB). The anatomy of the LHB is unique in that it comprises intra- and extra-articular portions, each exposed to differing loading patterns. Eleven LHBs post-tenotomy were sectioned, fixed in formalin, and stained (H and E; Alcian Blue), and gross structural organization of collagen measured using polarized light microscopy. Protein expression of intra- and extra-articular portions of the tenotomized biceps for IGF-I, collagen III, and MMP-1, -2, -3, and -13 was determined with Western blot analyses. The intra-articular LHB exhibited significantly greater histological evidence of tendinopathy inclusive of increased proteoglycan (p < 0.05) and decreased organization as measured by polarized light microscopy (p < 0.01). The intra-articular LHB also had significantly increased expression of collagen type III (p < 0.01) and of MMP-1 and 3 (p < 0.01, p < 0.05 respectively). No significant differences were found for IGF-I or for MMP-2 and -13. The intra-articular LHB exhibited histological characteristics of tendinopathy. Protein expression of the intra-articular LHB did not universally display signs of tendinopathy in comparison to the extra-articular portion of the tendon. PMID:19340876

Joseph, Michael; Maresh, Carl M; McCarthy, Mary Beth; Kraemer, William J; Ledgard, Felicia; Arciero, Cristina L; Anderson, Jeffrey M; Nindl, Bradley C; Mazzocca, Augustus D

2009-10-01

326

Exploring the role of hypercholesterolemia in tendon health and repair  

PubMed Central

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

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

2014-01-01

327

Isolation and growth characteristics of adult human tendon fibroblasts.  

PubMed Central

An explant method for the isolation of fibroblasts from adult human tendon is described. Cells were successfully isolated from 22 out of 27 common biceps tendons obtained from cadaveric donors (age range 11-83 years). The fibroblasts could be maintained in culture using standard methods and morphologically resembled those of synovial rather than dermal origin. Growth characteristics of 12 cell lines were assessed by deoxyribose nucleic acid (DNA) synthesis using [3H]thymidine incorporation in response to stimulation by fetal calf serum. Cells obtained separately from superficial and deep parts of the tendons produced almost identical responses. No significant reduction in growth response with increasing age was found when related to the age of the donor. Therefore this study did not show any age related defect in the short term tendon fibroblast replicative responses to serum. Images PMID:3592800

Chard, M D; Wright, J K; Hazleman, B L

1987-01-01

328

Traumatic extensor tendon dislocation in a boxer: a case study.  

PubMed

An elite collegiate boxer developed extensor tendon subluxation in the small finger of his dominant right hand. He was thought to have a radial sagittal band disruption and was allowed to complete his season with custom padding. Surgical exploration revealed intact sagittal bands with divergent dislocation of the two extensor tendons to the small finger with underlying capsular rupture. These lesions were repaired and he successfully returned to boxing. Soft tissue injuries to the dorsal MCP joint may involve the collateral ligaments, the sagittal bands, the extensor tendons, or the joint capsule. Symptoms usually involve persistent pain, swelling, and tendon subluxation or dislocation. Accurate recognition and treatment is crucial as nonoperative treatment is generally unsuccessful and surgical reconstruction is required for optimal return to function. PMID:14523299

Bents, Robert Thurston; Metz, John Patrick; Topper, Steven Mark

2003-10-01

329

[Neglected ipsilateral simultaneous ruptures of patellar and quadriceps tendon].  

PubMed

Neglected patellar and quadriceps tendon rupture is a rare injury, but ipsilateral simultaneous patellar and quadriceps tendon rupture was not described in the literature to our knowledge. In this article, we report a 40-year-old healthy male patient with neglected ipsilateral patellar and quadriceps tendon ruptures treated by peroneus longus tendon autograft. Patient had received some conservative and surgical treatments for patellar fracture before applying to our clinic. After our treatment using peroneus longus autograft and interference nails, patient was immobilized for six weeks in cylindrical cast. Flexion exercises and full weight bearing were started after cast removal. Patient had no complaint at postoperative second year. Patient was a neglected case. Surgical repair and early rehabilitation enabled us to achieve a satisfactory outcome. PMID:25741921

Karahasano?lu, ?lker; Yolo?lu, Osman; Kerimo?lu, Servet; Turhan, Ahmet U?ur

2015-04-01

330

A model of muscle-tendon function in human walking  

E-print Network

In order to motivate the design of legged machines that walk as humans do, this thesis investigates how leg muscles and tendons work mechanically during level-ground human walking at self-selected speeds. I hypothesize ...

Endo, Ken, Ph. D. Massachusetts Institute of Technology

2012-01-01

331

Different regions of bovine deep digital flexor tendon exhibit distinct elastic, but not viscous, mechanical properties under both compression and shear loading.  

PubMed

Tendons in different locations function in unique, and at times complex, in vivo loading environments. Specifically, some tendons are subjected to compression, shear and/or torsion in addition to tensile loading, which play an important role in regulating tendon properties. To date, there have been few studies evaluating tendon mechanics when loaded in compression and shear, which are particularly relevant for understanding tendon regions that experience such non-tensile loading during normal physiologic function. The objective of this study was to evaluate mechanical responses of different regions of bovine deep digital flexor tendons (DDFT) under compressive and shear loading, and correlate structural characteristics to functional mechanical properties. Distal and proximal regions of DDFT were evaluated in a custom-made loading system via three-step incremental stress-relaxation tests. A two-relaxation-time solid linear model was used to describe the viscoelastic response. Results showed large differences in the elastic behavior between regions: distal region stresses were 4-5 times larger than proximal region stresses during compression and 2-3 times larger during shear. Surprisingly, the viscous (i.e., relaxation) behavior was not different between regions for either compression or shear. Histological analysis showed that collagen and proteoglycan in the distal region distributed differently from the proximal region. Results demonstrate mechanical differences between two regions of DDFT under compression and shear loading, which are attributed to variations of composition and microstructural organization. These findings deepen our understanding of structure-function relationships of tendon, particularly for tissues adapted to supporting combinations of tension, compression, and shear in physiological loading environments. PMID:25113805

Fang, Fei; Sawhney, Amrita S; Lake, Spencer P

2014-09-22

332

The flexor tendon pulley system and rock climbing.  

PubMed

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

Crowley, Timothy P

2012-06-01

333

A Simple Grafting Method to Repair Irreparable Distal Biceps Tendon  

Microsoft Academic Search

Irreparable distal biceps tendon tears typically are treated using a free tendon graft. We asked whether our new method to\\u000a fix the graftusing two suture anchorsyields similar results to our previous bone canal method. We compared the two methods\\u000a for strength, endurance, and clinical findings. There were two groups, the suture anchor group (Group A, seven patients) and\\u000a the bone

Martti Vastamki; Heidi Vastamki

2008-01-01

334

Patellar Tendon Ruptures in National Football League Players  

Microsoft Academic Search

Background: Although knee injuries are common among professional football players, ruptures of the patellar tendon are relatively rare. Predisposing factors, mechanisms of injury, treatment guidelines, and recovery expectations are not well established in high-level athletes.Hypothesis: Professional football players with isolated rupture of the patellar tendon treated with timely surgical repair will return to their sport.Study Design: Case series; Level of

Martin Boublik; Theodore Schlegel; Ryan Koonce; James Genuario; Charles Lind; David Hamming

2011-01-01

335

Temporal response of canine flexor tendon to limb suspension  

PubMed Central

Tendon disuse, or stress deprivation, frequently accompanies clinical disorders and treatments, yet the metabolism of tendons subject to stress deprivation has rarely been investigated systematically. The effects of stress deprivation on canine flexor tendon were investigated in this study. One adult canine forepaw was suspended for 21 or 42 days. Control forepaws were collected from dogs that had no intervention on their limbs and paws. The expression of collagen I and III was not significantly altered in the tendons disused for 21 days but was significantly decreased at 42 days (P < 0.03). The expression of collagen II, aggrecan, decorin, and fibronectin was significantly decreased in the tendons in the suspended limbs at 21 days (P < 0.002) and further reduced at 42 days. With stress deprivation, the expression of matrix metalloproteinase 2 (MMP2) was significantly increased (P < 0.004) at 21 and 42 days. The expression of MMP3 was significantly decreased at 21 and 42 days (P < 0.03). The expression of MMP13 was not altered with stress deprivation at 21 and 42 days. The expression of MMP14 was significantly increased at 21 days (P = 0.0015) and returned to the control level at 42 days. Tissue inhibitor of metalloproteinase 1 (TIMP1) expression was decreased after the limbs were suspended for 42 days (P = 0.0043), but not 21 days. However, TIMP2 expression was not significantly different from control at 21 or 42 days. Furthermore, the cross-sectional area of the stress-deprived tendons at 42 days was decreased compared with the control group (P < 0.01). The intervention method in this study did not result in any alteration of stiffness of the tendon. Our study demonstrated that stress deprivation decreases the anabolic process and increases the catabolic process of extracellular matrix in flexor tendon. PMID:20947711

Thoreson, Andrew R.; Cha, Stephen S.; Zhao, Chunfeng; An, Kai-Nan; Amadio, Peter C.

2010-01-01

336

Direct Repair without Augmentation of Patellar Tendon Avulsion following TKA  

PubMed Central

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

Kumar, Nishikant; Yadav, Chandrashekhar; Kumar, Ashok

2015-01-01

337

Surface modification counteracts adverse effects associated with immobilization after flexor tendon repair.  

PubMed

Although post-rehabilitation is routinely performed following flexor tendon repair, in some clinical scenarios post-rehabilitation must be delayed. We investigated modification of the tendon surface using carbodiimide derivatized hyaluronic acid and lubricin (cd-HA-Lub) to maintain gliding function following flexor tendon repair with postoperative immobilization in a in vivo canine model. Flexor digitorum profundus tendons from the 2nd and 5th digits of one forepaw of six dogs were transected and repaired. One tendon in each paw was treated with cd-HA-Lub; the other repaired tendon was not treated. Following tendon repair, a forearm cast was applied to fully immobilize the operated forelimb for 10 days, after which the animals were euthanized. Digit normalized work of flexion (nWOF) and tendon gliding resistance were assessed. The nWOF of the FDP tendons treated with cd-HA-Lub was significantly lower than the nWOF of the untreated tendons (p < 0.01). The gliding resistance of cd-HA-Lub treated tendons was also significantly lower than that of the untreated tendons (p < 0.05). Surface treatment with cd-HA-Lub following flexor tendon repair provides an opportunity to improve outcomes for patients in whom the post-operative therapy must be delayed after flexor tendon repair. PMID:22714687

Zhao, Chunfeng; Sun, Yu-Long; Jay, Gregory D; Moran, Steven L; An, Kai-Nan; Amadio, Peter C

2012-12-01

338

The anatomical footprint of the Achilles tendon: a cadaveric study.  

PubMed

We dissected 12 fresh-frozen leg specimens to identify the insertional footprint of each fascicle of the Achilles tendon on the calcaneum in relation to their corresponding muscles. A further ten embalmed specimens were examined to confirm an observation on the retrocalcaneal bursa. The superficial part of the insertion of the Achilles tendon is represented by fascicles from the medial head of the gastrocnemius muscle, which is inserted over the entire width of the inferior facet of the calcaneal tuberosity. In three specimens this insertion was in continuity with the plantar fascia in the form of periosteum. The deep part of the insertion of the Achilles tendon is made of fascicles from the soleus tendon, which insert on the medial aspect of the middle facet of the calcaneal tuberosity, while the fascicles of the lateral head of the gastrocnemius tendon insert on the lateral aspect of the middle facet of the calcaneal tuberosity. A bicameral retrocalcaneal bursa was present in 15 of the 22 examined specimens. This new observation and description of the insertional footprint of the Achilles tendon and the retrocalcaneal bursa may allow a better understanding of the function of each muscular part of the gastrosoleus complex. This may have clinical relevance in the treatment of Achilles tendinopathies. PMID:25274919

Ballal, M S; Walker, C R; Molloy, A P

2014-10-01

339

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

PubMed Central

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

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

2013-01-01

340

Distal biceps brachii tendon rupture resulting in acute compartment syndrome.  

PubMed

Distal biceps brachii tendon rupture is an uncommon injury. Compartment syndrome of the upper arm is rarely described in the literature. The diagnosis of upper arm compartment syndrome requires a high index of suspicion, and emergent surgical treatment with fasciotomy in the acute setting is necessary to avoid devastating neurovascular complications. This article reports a case of acute compartment syndrome of the anterior compartment of the upper arm after a complete rupture of the distal biceps brachii tendon. A healthy 45-year-old man presented with increasing arm pain; paresthesia in the lateral antebrachial cutaneous nerve distribution; and a tense, swollen anterior compartment of his upper arm. Side port catheter absolute pressure measurement was 83 mm Hg with a diastolic blood pressure of 92 mm Hg. The patient underwent an emergent fasciotomy and was found to have a complete rupture of his distal biceps brachii tendon. He subsequently underwent distal biceps tendon repair and delayed primary closure of his incision. Postoperatively, his paresthesia improved and he has no neurological deficit. There is a paucity of case reports describing compartment syndrome after rupture of either the proximal or distal end of the biceps brachii tendon, and none of the reports describe compartment syndrome of the upper arm after rupture of the distal biceps tendon. This article highlights an unusual complication of an uncommon injury and reviews diagnostic and treatment principles for the management of acute compartment syndrome of the upper arm. PMID:24200459

Grandizio, Louis C; Suk, Michael; Feltham, Glen T

2013-11-01

341

Catabolism of aggrecan, decorin and biglycan in tendon.  

PubMed Central

We have examined the catabolism of the proteoglycans aggrecan, decorin and biglycan in fresh tendon samples and in explant cultures of tissue from the tensional and compressed regions of young and mature bovine tendons. A panel of well-characterized antibodies that recognize glycosaminoglycan or protein (linear or neoepitope) sequences was used to detect proteoglycans and proteoglycan degradation products that were both retained within the tissue and released into the culture medium. In addition, a reverse-transcriptase-mediated PCR analysis was used to examine the mRNA expression patterns of tendon proteoglycans and aggrecanases. The results of this study indicate a major role for aggrecanase(s) in the catabolism of aggrecan in bovine tendon. The study also provides a characterization of glycosaminoglycan epitopes associated with the proteoglycans of tendon, illustrating age-related changes in the isomers of chondroitin sulphate disaccharides that remain attached to the core protein glycosaminoglycan linkage region after digestion with chondroitinase ABC. Evidence for a rapid turnover of the small proteoglycans decorin and biglycan was also observed, indicating additional molecular pathways that might compromise the integrity of the collagen matrix and potentially contribute to tendon dysfunction after injury and during disease. PMID:10926842

Rees, S G; Flannery, C R; Little, C B; Hughes, C E; Caterson, B; Dent, C M

2000-01-01

342

Biomimetic Scaffold Design for Functional and Integrative Tendon Repair  

PubMed Central

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 underscore the clinical need for alternative grafting solutions. The two 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 future directions section. PMID:22244070

Zhang, Xinzhi; Bogdanowicz, Danielle; Erisken, Cevat; Lee, Nancy M.; Lu, Helen H.

2012-01-01

343

Principles and biomechanics of muscle tendon unit transfer: application in temporalis muscle tendon transposition for smile improvement in facial paralysis.  

PubMed

Muscle tendon unit (MTU) transfer is a common procedure performed to restore hand function after peripheral nerve or spinal cord injury. The principles of MTU transfer established for hand surgery can be adopted to optimize the dynamic excursion of the temporalis tendon transfer procedure for facial reanimation. Additionally, the force generating ability of a transferred MTU depends on the ideal length-tension relationship of the donor muscle. There are unclear guideline for selecting the ideal tension at which a transferred MTU will generate maximum force and excursion and current practice often leads to overstretch and suboptimal actin myosin interaction. The use of intraoperative electrical stimulation is an option for determining the ideal tension to optimize excursion of transferred temporalis tendon units in simile restoration. Understanding the biomechanics and principles of MTU and applying it to the temporalis tendon transfer procedure is necessary to improve its use in facial reanimation. PMID:23208742

Boahene, Kofi D O

2013-02-01

344

The management of chronic rupture of the Achilles tendon: minimally invasive peroneus brevis tendon transfer.  

PubMed

We hypothesised that a minimally invasive peroneus brevis tendon transfer would be effective for the management of a chronic rupture of the Achilles tendon. In 17 patients (three women, 14 men) who underwent minimally invasive transfer and tenodesis of the peroneus brevis to the calcaneum, at a mean follow-up of 4.6 years (2 to 7) the modified Achilles tendon total rupture score (ATRS) was recorded and the maximum circumference of the calf of the operated and contralateral limbs was measured. The strength of isometric plantar flexion of the gastrocsoleus complex and of eversion of the ankle were measured bilaterally. Functional outcomes were classified according to the four-point Boyden scale. At the latest review, the mean maximum circumference of the calf of the operated limb was not significantly different from the pre-operative mean value, (41.4 cm, 32 to 50 vs 40.6cm, 33 to 46; p = 0.45), and not significantly less than that of the contralateral limb (43.1 cm, 35 to 52; p = 0.16). The mean peak torque (244.6 N, 125 to 367) and the strength of eversion of the operated ankle (149.1 N, 65 to 240) were significantly lower (p < 0.01) than those of the contralateral limb (mean peak torque 289, 145 to 419; strength of eversion: 175.2, 71 to 280). The mean ATRS significantly improved from 58 pre-operatively (35 to 68) to 91 (75 to 97; 95% confidence interval 85.3 to 93.2) at the time of final review. Of 13 patients who practised sport at the time of injury, ten still undertook recreational activities. This procedure may be safely performed, is minimally invasive, and allows most patients to return to pre-injury sport and daily activities. Cite this article: Bone Joint J 2015;97-B:353-7. PMID:25737519

Maffulli, N; Oliva, F; Costa, V; Del Buono, A

2015-03-01

345

Unloaded rat Achilles tendons continue to grow, but lose viscoelasticity.  

PubMed

Tendons can function as springs and thereby preserve energy during cyclic loading. They might also have damping properties, which, hypothetically, could reduce risk of microinjuries due to fatigue at sites of local stress concentration within the tendon. At mechanical testing, damping will appear as hysteresis. How is damping influenced by training or disuse? Does training decrease hysteresis, thereby making the tendon a better spring, or increase hysteresis and thus improve damping? Seventy-eight female 10-wk-old Sprague-Dawley rats were randomized to three groups. Two groups had botulinum toxin injected into the calf muscles to unload the left Achilles tendon through muscle paralysis. One of these groups was given doxycycline, as a systemic matrix metalloproteinase inhibitor. The third group served as loaded controls. The Achilles tendons were harvested after 1 or 6 wk for biomechanical testing. An increase with time was seen in tendon dry weight, wet weight, water content, transverse area, length, stiffness, force at failure, and energy uptake in all three groups (P < 0.001 for each parameter). Disuse had no effect on these parameters. Creep was decreased with time in all groups. The only significant effect of disuse was on hysteresis (P = 0.004) and creep (P = 0.007), which both decreased with disuse compared with control, and on modulus, which was increased (P = 0.008). Normalized glycosaminoglycan content was unaffected by time and disuse. No effect of doxycycline was observed. The results suggest that in growing animals, the tendons continue to grow regardless of mechanical loading history, whereas maintenance of damping properties requires mechanical stimulation. PMID:17412787

Eliasson, Pernilla; Fahlgren, Anna; Pasternak, Bjrn; Aspenberg, Per

2007-08-01

346

Distal biceps tendon injuries--current treatment options.  

PubMed

Three percent of all biceps tendon ruptures occur at the distal aspect, where the tendon inserts into the radial tuberosity. Distal bicep tendon ruptures typically occur in middle-aged males after an eccentric extension load is applied to the elbow. Patients usually complain of a sudden, sharp, and painful tearing sensation in the antecubital region, with a palpable defect. The biceps squeeze and hook tests are specific maneuvers by which to diagnose distal biceps ruptures on physical examination. Magnetic resonance imaging (MRI) or ultrasound maybe be helpful to distinguish between partial and complete tears. Anatomic studies suggest there are two distinct insertions for the short and long heads of the distal biceps. The short head may be a more powerful flexor, and the long head may be a more powerful supinator. Nonoperative treatment typically results in loss of flexion and supination strength and endurance. Early anatomic re-attachment is the goal. Surgical approaches include one- or two-incision techniques, and tendon fixation methods include the use of suture anchors, bone tunnels, an endobutton, or biotenodesis screws. Biomechanical studies have shown that endobuttons have higher load-to-failure strengths, compared to the other fixation methods. However, clinical studies have demonstrated that patients do well regardless of surgical approach or fixation method. Possible complications include nerve injuries, heterotopic ossification, postoperative fracture, tendon rerupture, complex regional pain syndrome, and wound infection. Partial ruptures are significantly less common and initially can be treated conservatively. Chronic tears are more difficult to treat because of possible tendon retraction and poor tissue quality. Tendon grafts using semitendinosus, fascia lata, hamstring, Achilles (calcaneal), or flexor carpi radialis have been successfully used for length restoration in these cases. PMID:20632985

Quach, Tony; Jazayeri, Reza; Sherman, Orrin H; Rosen, Jeffrey E

2010-01-01

347

Bone loss following tendon laceration, repair and passive mobilization.  

PubMed

Little is known about the localized changes in bone mass that occur following tendon or ligament injury. Interruption of normal load transfer at the insertion site will presumably lead to a localized loss of bone, although few data exist to support this claim. To test this hypothesis, we transected the canine flexor digitorum profundus (FDP) tendon from its insertion, and either repaired it using a trans-osseous suture technique or left it unrepaired (laceration only). Post-operatively, forelimbs in the repair group were cast immobilized except for 10 min of daily passive mobilization rehabilitation, whereas in the laceration only group dogs were allowed full weight bearing. At 5-42 days post-injury, we assessed bone mineral density (BMD) using pQCT and osteoclast surface by histomorphometry. We measured significant bone loss in the distal phalanx after combined FDP tendon laceration, repair, and post-operative passive mobilization, with BMD decreases of 20%, 40%, and 41% at 10, 21, and 42 days (p<0.01). Moreover, we observed that passive mobilization and tendon laceration each contributed independently to the observed bone loss. At 42 days, BMD was reduced by 21% in bones that were not injured but were subjected to the post-operative passive mobilization protocol, while BMD was reduced by 28% in bones subjected to tendon laceration and full weight bearing (p<0.01). In both the passive mobilization and laceration specimens, we counted significantly increased osteoclasts after only 7-10 days, and these increases persisted through 42 days (p<0.05). We conclude that rapid and sustained bone resorption leads to significant bone loss in the 6-week period following flexor tendon injury and repair. This bone loss may impact healing by impeding the restoration of a strong tendon-bone interface. PMID:14554210

Ditsios, Konstantinos; Boyer, Martin I; Kusano, Nozomu; Gelberman, Richard H; Silva, Matthew J

2003-11-01

348

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

NASA Astrophysics Data System (ADS)

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.

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

2007-09-01

349

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

PubMed Central

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

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

2014-01-01

350

Extended Healing Validation of an Artificial Tendon to Connect the Quadriceps Muscle to the Tibia: 180-day Study  

PubMed Central

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 nonliving 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 contra lateral unoperated control legs at 180 days. Maximum forces in the operated leg (vs. unoperated) were 1400 93N (vs. 1179 61 N), linear stiffnesses were 33 3 N/mm (vs. 37 4N/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 orthopaedic oncology, revision arthroplasty, tendon transfer, and tendon injury reconstruction. PMID:22179930

Melvin, Alan J.; Litsky, Alan S.; Mayerson, Joel L.; Stringer, Keith; Juncosa-Melvin, Natalia

2011-01-01

351

Extended healing validation of an artificial tendon to connect the quadriceps muscle to the Tibia: 180-day study.  

PubMed

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

Melvin, Alan J; Litsky, Alan S; Mayerson, Joel L; Stringer, Keith; Juncosa-Melvin, Natalia

2012-07-01

352

Lateral epicondylalgia: midlife crisis of a tendon.  

PubMed

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

Luk, James K H; Tsang, Raymond C C; Leung, H B

2014-04-01

353

The behavior of rotator cuff tendon cells in three-dimensional culture  

E-print Network

The rotator cuff is composed of the supraspinatus, infraspinatus, subcapularis, and teres minor tendons. Rotator cuff injuries are common athletic and occupational injuries that surgery cannot fully repair. Therefore tendon ...

Gill, Harmeet (Harmeet Kaur)

2007-01-01

354

Uncovering the cellular and molecular changes in tendon stem/progenitor cells attributed to tendon aging and degeneration  

PubMed Central

Although the link between altered stem cell properties and tissue aging has been recognized, the molecular and cellular processes of tendon aging have not been elucidated. As tendons contain stem/progenitor cells (TSPC), we investigated whether the molecular and cellular attributes of TSPC alter during tendon aging and degeneration. Comparing TSPC derived from young/healthy (Y-TSPC) and aged/degenerated human Achilles tendon biopsies (A-TSPC), we observed that A-TSPC exhibit a profound self-renewal and clonogenic deficits, while their multipotency was still retained. Senescence analysis showed a premature entry into senescence of the A-TSPC, a finding accompanied by an upregulation of p16INK4A. To identify age-related molecular factors, we performed microarray and gene ontology analyses. These analyses revealed an intriguing transcriptomal shift in A-TSPC, where the most differentially expressed probesets encode for genes regulating cell adhesion, migration, and actin cytoskeleton. Time-lapse analysis showed that A-TSPC exhibit decelerated motion and delayed wound closure concomitant to a higher actin stress fiber content and a slower turnover of actin filaments. Lastly, based on the expression analyses of microarray candidates, we suggest that dysregulated cellmatrix interactions and the ROCK kinase pathway might be key players in TSPC aging. Taken together, we propose that during tendon aging and degeneration, the TSPC pool is becoming exhausted in terms of size and functional fitness. Thus, our study provides the first fundamental basis for further exploration into the molecular mechanisms behind tendon aging and degeneration as well as for the selection of novel tendon-specific therapeutical targets. PMID:23826660

Kohler, Julia; Popov, Cvetan; Klotz, Barbara; Alberton, Paolo; Prall, Wolf Christian; Haasters, Florian; Mller-Deubert, Sigrid; Ebert, Regina; Klein-Hitpass, Ludger; Jakob, Franz; Schieker, Matthias; Docheva, Denitsa

2013-01-01

355

The effects of chronic unloading and gap formation on tendon-to-bone healing in a rat model of massive rotator cuff tears  

PubMed Central

The objective of this study was to understand the effect of pre-repair rotator cuff chronicity on post-repair healing outcomes using a chronic and acute multi-tendon rat rotator cuff injury model. Full-thickness dual tendon injuries (supra- and infraspinatus) were created unilaterally in adult male Sprague Dawley rats, and left chronically detached for 8 or 16 weeks. After chronic detachment, tears were repaired and acute dual tendon injuries were created and immediately repaired on contralateral shoulders. Tissue level outcomes for bone, tendon, and muscle were assessed 4 or 8 weeks after repair using histology, microcomputed tomography, biomechanical testing, and biochemical assays. Substantial gap formation was seen in 35% of acute repairs and 44% of chronic repairs. Gap formation negatively correlated with mechanical and structural outcomes for both healing time points regardless of injury duration. Bone and histomorphometry, as well as biomechanics, were similar between acute and chronic injury and repair regardless of chronicity and duration of healing. This study was the first to implement a multi-tendon rotator cuff injury with surgical repair following both chronic and acute injuries. Massive tear in a rodent model resulted in gap formation regardless of injury duration which had detrimental effects on repair outcomes. PMID:24243733

Killian, Megan L.; Cavinatto, Leonardo; Shah, Shivam A.; Sato, Eugene J.; Ward, Samuel R.; Havlioglu, Necat; Galatz, Leesa M.; Thomopoulos, Stavros

2014-01-01

356

Loss of Drosophila A-type lamin C initially causes tendon abnormality including disintegration of cytoskeleton and nuclear lamina in muscular defects.  

PubMed

Lamins are the major components of nuclear envelope architecture, being required for both the structural and informational roles of the nuclei. Mutations of lamins cause a spectrum of diseases in humans, including muscular dystrophy. We report here that the loss of the A-type lamin gene, lamin C in Drosophila resulted in pupal metamorphic lethality caused by tendon defects, matching the characteristics of human A-type lamin revealed by Emery-Dreifuss muscular dystrophy (EDMD). In tendon cells lacking lamin C activity, overall cell morphology was affected and organization of the spectraplakin family cytoskeletal protein Shortstop which is prominently expressed in tendon cells gradually disintegrated, notably around the nucleus and in a manner correlating well with the degradation of musculature. Furthermore, lamin C null mutants were efficiently rescued by restoring lamin C expression to shortstop-expressing cells, which include tendon cells but exclude skeletal muscle cells. Thus the critical function of A-type lamin C proteins in Drosophila musculature is to maintain proper function and morphology of tendon cells. PMID:22982669

Uchino, Ryo; Nonaka, Yu-Ki; Horigome, Tuneyoshi; Sugiyama, Shin; Furukawa, Kazuhiro

2013-01-01

357

Ligament and tendon repair with an absorbable polymer-coated carbon fiber stent.  

PubMed

Ribbon-like composite structures of filamentous carbon fiber and absorbable polymers have been used in the repair and replacement of both tendons and ligaments. The composite acts as a scaffold upon which new collagenous tissue can grow and has proved successful in a variety of animal models. The results of the first three years of human clinical trials have revealed ingrowth potential similar to that seen in the animal studies. Most patients have shown significant improvement, with many demonstrating good to excellent stability and function. PMID:3030478

Alexander, H; Weiss, A B; Parsons, J R

1986-01-01

358

Acute ulnar nerve compression syndrome in a powerlifter with triceps tendon rupture--a case report.  

PubMed

We report on the case of a bodybuilder and powerlifter who suffered from triceps tendon rupture complicated by acute ulnar nerve compression syndrome. The diagnosis was made clinically, radiologically, and sonographically. Ultrasound was helpful to demonstrate a large hematoma at the site of the injury. Early surgical intervention confirmed the presence of the hematoma compressing the ulnar nerve and led to a complete restoration of ulnar nerve and triceps muscle function. Few reports on distal triceps rupture have been published but its complication by acute ulnar nerve compression has not been reported on yet despite the close anatomical relationship of both structures. PMID:10853704

Duchow, J; Kelm, J; Kohn, D

2000-05-01

359

A 3D lower limb musculoskeletal model for simultaneous estimation of musculo-tendon, joint contact, ligament and bone forces during gait.  

PubMed

Musculo-tendon forces and joint reaction forces are typically estimated using a two-step method, computing first the musculo-tendon forces by a static optimization procedure and then deducing the joint reaction forces from the force equilibrium. However, this method does not allow studying the interactions between musculo-tendon forces and joint reaction forces in establishing this equilibrium and the joint reaction forces are usually overestimated. This study introduces a new 3D lower limb musculoskeletal model based on a one-step static optimization procedure allowing simultaneous musculo-tendon, joint contact, ligament and bone forces estimation during gait. It is postulated that this approach, by giving access to the forces transmitted by these musculoskeletal structures at hip, tibiofemoral, patellofemoral and ankle joints, modeled using anatomically consistent kinematic models, should ease the validation of the model using joint contact forces measured with instrumented prostheses. A blinded validation based on four datasets was made under two different minimization conditions (i.e., C1 - only musculo-tendon forces are minimized, and C2 - musculo-tendon, joint contact, ligament and bone forces are minimized while focusing more specifically on tibiofemoral joint contacts). The results show that the model is able to estimate in most cases the correct timing of musculo-tendon forces during normal gait (i.e., the mean coefficient of active/inactive state concordance between estimated musculo-tendon force and measured EMG envelopes was C1: 65.87% and C2: 60.46%). The results also showed that the model is potentially able to well estimate joint contact, ligament and bone forces and more specifically medial (i.e., the mean RMSE between estimated joint contact force and in vivo measurement was C1: 1.14BW and C2: 0.39BW) and lateral (i.e., C1: 0.65BW and C2: 0.28BW) tibiofemoral contact forces during normal gait. However, the results remain highly influenced by the optimization weights that can bring to somewhat aphysiological musculo-tendon forces. PMID:24210475

Moissenet, Florent; Chze, Laurence; Dumas, Raphal

2014-01-01

360

Endoscopic Transtendinous Repair for Partial-Thickness Proximal Hamstring Tendon Tears  

PubMed Central

Partial tears of the proximal hamstring tendon can successfully be managed with tendon repair in cases of failed conservative management. As in partial-thickness gluteus medius repair, a transtendinous technique can be used to repair partial-thickness undersurface tears of the hamstring origin. This report details an endoscopic transtendinous approach for the treatment of partial-thickness hamstring tendon tears. PMID:24749032

Jackson, Timothy J.; Trenga, Anthony; Lindner, Dror; El-Bitar, Youseff; Domb, Benjamin G.

2014-01-01

361

Spontaneous isolated rupture of popliteus tendon presenting as locked knee: case study and literature review  

Microsoft Academic Search

Traumatic isolated rupture of the popliteus tendon has been described as a rare cause of haemarthrosis of the knee. There has been only one reported case of spontaneous rupture of the popliteus tendon in the English literature before. We present the case of a 70-year-old lady who had spontaneous rupture of the popliteus tendon without history of significant trauma. She

Ehab Kheir; Ali Ghoz; K. Gorgees; David MacDonald; David Limb; Peter Giannoudis

2006-01-01

362

An experimental investigation of friction and wear of polyethylene sheathings of external tendons at deviation points  

Microsoft Academic Search

This article is dealing with the experimental inves tigation of friction and wear of polyethylene sheat hings under extreme loading. PE-sheathings are used as corrosion protec tion system of external tendons of post tensioned c oncrete bridges. At deviation points the material is stressed perpen dicular to the axis of the steel tendons. Whilst lo ad is applied the tendons

Hermann Weiher; Konrad Zilch

363

Ultrasound echo is related to stress and strain in tendon Sarah Duenwald a  

E-print Network

n f o Article history: Accepted 30 September 2010 Keywords: Tendon Ultrasound Echo intensity of tendon in vitro. Porcine digital flexor tendons were cyclically loaded in a mechanical testing system, and is a promising metric to acquire in vivo mechanical data noninvasively. & 2010 Elsevier Ltd. All rights reserved

Lakes, Roderic

364

Autogenous palmaris longus tendon as frontalis suspension material for ptosis correction in children  

Microsoft Academic Search

Purpose: To determine the safety and efficacy of autogenous palmaris longus tendon as a sling material in frontalis suspension surgery for ptosis correction in children.Methods: In a prospective study, the authors evaluated 15 frontalis sling suspension surgeries using palmaris longus tendon in 14 consecutive children with congenital ptosis. The method of harvesting the palmaris longus tendon is described in detail.Results:

Dennis S. C. Lam; Joan S. K. Ng; George P. M. Cheng; Randa T. H. Li

1998-01-01

365

Early active mobilization of tendon grafts using mesh reinforced suture techniques  

Microsoft Academic Search

The flexor digitorum profundus tendon in 11 digits with division of both flexor tendons in zone 2 was reconstructed with a palmaris longus tendon graft in a two-stage procedure. The distal and proximal fixation of the graft was reinforced with a polyester mesh sleeve placed around the ends of the graft during stage 1. All digits were mobilized with a

K. L. Silfverskild; E. J. May

1995-01-01

366

Cut Palmaris Longus TendonTo Repair or not to Repair?  

Microsoft Academic Search

It is suggested in certain circumstances, that a divided palmaris longus tendon should be repaired, as it is an ideal choice for a tendon graft, or could be of use as a tendon transfer. The musculotendinous unit may be of use as an autogenous free graft.

K. SARANGAPANI; H. G. BROWN

1977-01-01

367

Conservative management of partial extensor tendon lacerations greater than half the width of the tendon in manual workers.  

PubMed

Conservative management (without suturing or splints) of partial extensor tendon lacerations greater than half the width of the tendon has not been previously investigated. In this prospective study, a total of 45 injured tendons (with lacerations involving 55%-90% of the width of the tendon) in 39 patients were treated conservatively. Injury zones I, III, and V of the fingers; and zones I and III of the thumb were excluded. Immediate non-resistive active mobilization was initiated and continued for 4 weeks, followed by resistive exercises. Patients were allowed to go back to work after 6 weeks. There were no cases of ruptures, triggering, infection, or complex regional pain syndrome. At final follow-up (8-9 months after injury), all patients obtained full range of motion with no extension lags. All patients were able to go back to normal duties. We conclude that early active motion without the use of splints or sutures in major extensor tendon lacerations in zones II, IV, VI-VIII of the fingers; and zones II, IV, and V of the thumb is safe. PMID:25749213

Al-Qattan, Mohammad M

2015-04-01

368

Stem cell research and clinical development in tendon repair  

PubMed Central

Summary Stem cells are one of the most fascinating areas in regenerative medicine today. They play a crucial role in development and regeneration and are defined as cells that continuously reproduce themselves while maintaining the ability to differentiate into various cell types. Stem cells are found at all developmental stages, from embryonic stem cells (ESCs) which differentiate into all cell types, to adult stem cells (ASCs) which are responsible for tissue regeneration. Studies using animal models have shown promising results following cell therapy for induced injury in musculoskeletal system, including tendon healing, but the results can be variable. Alternative sources for cell therapy in tendon pathology may include ESCs, ASCs (bone marrow, adipose tissue or tendon derived stem cells) or induced pluripotent stem cells (iPSCs). While ethical and safety concerns currently forbid clinical application of ESCs and iPSCs, initial clinical trials with ASCs are promising. PMID:23738298

Filomeno, Paola; Dayan, Victor; Tourio, Cristina

2012-01-01

369

Subcoracoid impingement and subscapularis tendon: is there any truth?  

PubMed Central

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

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

2013-01-01

370

Torque resolver design for tendon-driven manipulators  

SciTech Connect

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.

Lee, J.J.; Tsai, Lung-Wen

1992-08-01

371

Torque resolver design for tendon-driven manipulators  

SciTech Connect

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.

Lee, J.J.; Tsai, Lung-Wen.

1992-01-01

372

Surgical treatment options for patella tendon rupture, Part I: Acute.  

PubMed

Patella tendon rupture is a debilitating injury. Prompt diagnosis and treatment is essential to prevent retraction of the patella with subsequent adhesions and quadriceps contractures. In a young patient with an acute rupture, primary repair usually is possible with various methods described to protect the repair. In acute injuries with inadequate tissue, augmentation with hamstring tendons or allograft generally is necessary. Because of the different types of rupture and the possibility for poor quality tissue, the surgeon should always be prepared to combine different techniques to obtain tthe best repair. Continuous passive motion generally can be initiated early with a secure repair. In patients with a patella tendon ruptured that is promptly diagnosed, securely repaired, and followed closely through their rehabilitation, good results can be expected. PMID:16119282

Greis, Patrick E; Holmstrom, Michael C; Lahav, Amit

2005-07-01

373

Stem cell research and clinical development in tendon repair.  

PubMed

Stem cells are one of the most fascinating areas in regenerative medicine today. They play a crucial role in development and regeneration and are defined as cells that continuously reproduce themselves while maintaining the ability to differentiate into various cell types. Stem cells are found at all developmental stages, from embryonic stem cells (ESCs) which differentiate into all cell types, to adult stem cells (ASCs) which are responsible for tissue regeneration. Studies using animal models have shown promising results following cell therapy for induced injury in musculoskeletal system, including tendon healing, but the results can be variable. Alternative sources for cell therapy in tendon pathology may include ESCs, ASCs (bone marrow, adipose tissue or tendon derived stem cells) or induced pluripotent stem cells (iPSCs). While ethical and safety concerns currently forbid clinical application of ESCs and iPSCs, initial clinical trials with ASCs are promising. PMID:23738298

Filomeno, Paola; Dayan, Victor; Tourio, Cristina

2012-07-01

374

Posterior Tibial Tendon Dysfunction: An Overlooked Cause of Foot Deformity  

PubMed Central

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.

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

2015-01-01

375

Path planning for the deployment of tensegrity structures  

Microsoft Academic Search

Tensegrity structures consist of tendons (in tension) and bars (in compression). Tendons are strong, light, and foldable, so tensegrity structures have the potential to be light but strong and deployable. Pulleys, NiTi wire, or other actuators to selectively tighten some strings on a tensegrity structure can be used to control its shape. This article describes the problem of asymmetric reconfiguration

Jean-Paul Pinaud; Milenko Masic; Robert E. Skelton

2003-01-01

376

[Tendon entrapment after forearm distal bones fracture, case report].  

PubMed

In the aftermath of a forearm trauma, tendon contractures are difficult to diagnose and evoke nerve compression or muscle ischemia (Volkmann's syndrome). One rarely thinks of tendon incarceration within the fracture and the diagnosis is often made long after. During claw fingers retraction, it is known as "false Volkmann's syndrome" (Baudet and Lafond, 1979) or "pseudo Volkmann's syndrome" (Deeney et al., 1998). The authors report the case of ulnar claw fingers retraction, one year after a fracture of both bones of the forearm, treated surgically with recuperation of normal mobility immediately after emergence of the conflict. PMID:21856201

Piquilloud, G; Drap, J-L; Guerini, H; Le Viet, D

2011-09-01

377

Intermittent dislocation of the flexor hallucis longus tendon.  

PubMed

Dislocation of the flexor hallucis longus tendon is an exceptional occurrence. To our knowledge, this is the first case ever reported of an intermittent dislocation in a 17-year-old woman; she was a synchronised swimmer. She consulted for a right internal retro-malleolar syndrome. Voluntary "snap" was triggered by a mechanism which combined maximal ankle dorsiflexion and interphalangeal plantar flexion of the toes. Non-enhanced dynamic helical CT and axial MRI were performed, which revealed the dislocation of the right flexor hallucis longus tendon outside the posterior intertubercular talar groove. Static and dynamic imaging would appear to be required to make this uncommon diagnosis. PMID:12589485

Renard, M; Simonet, J; Bencteux, P; Raynaud, P; Biga, N; Thibot, J

2003-02-01

378

Bilateral carpal tunnel syndrome with anomalous palmaris profundus tendons.  

PubMed

This report presents the case of a 44-year-old man who presented with elective bilateral carpal tunnel decompression. At the operation, he was found to have bilateral palmaris profundus tendons within the carpal tunnel, impinging on the median nerve. In releasing both carpal tunnels, the patient's symptoms were alleviated and there was regain of full function. There have been very few documented cases of these anomalous tendons implicated in carpal tunnel syndrome and this case highlights how such anatomical variations are important in the surgical approach to carpal tunnel decompression. PMID:23088639

Razik, Aisha; Avisar, Erez; Sorene, Elliot

2012-12-01

379

Emergency department diagnosis of supraspinatus tendon calcification and shoulder impingement syndrome using bedside ultrasonography  

PubMed Central

A 45-year-old woman presented to the emergency department with a 2-day history of severe left shoulder pain made worse with movement. Emergency department (ED) bedside point-of-care static and dynamic ultrasound examination of the supraspinatus tendon revealed supraspinatus tendon calcification with impingement syndrome, and the patient was urgently referred to orthopedics after ED pain control was achieved. Bedside shoulder and supraspinatus tendon evaluation with static and dynamic ultrasonography can assist in the rapid diagnosis of supraspinatus tendon calcification and supraspinatus tendon impingement syndrome in the emergency department. PMID:23398632

2013-01-01

380

A 7Year Follow-up of Patellar Tendon and Hamstring Tendon Grafts for Arthroscopic Anterior Cruciate Ligament ReconstructionDifferences and Similarities  

Microsoft Academic Search

Background: For arthroscopic anterior cruciate ligament reconstruction, the most commonly used graft constructs are either the hamstring tendon or patellar tendon. Well-controlled, long-term studies are needed to determine the differences between the 2 materials.Hypothesis: There is a difference between hamstring and patellar tendon grafts in the clinical results of anterior cruciate ligament reconstructions at 7 years.Study Design: Cohort study; Level

Justin Roe; Leo A. Pinczewski; Vivianne J. Russell; Lucy J. Salmon; Tomomaro Kawamata; Melvin Chew

2005-01-01

381

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

PubMed

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. Theaim 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 1נ10(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

Gngrm?, Cans?n; Kolankaya, Drdane; Aydin, Erkin

2015-05-01

382

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

PubMed

The supraspinatus tendon is composed of 5 different layers consisting of intertwining bundles. On a front portion of the tendon, the layers become coated bundles which insert on the trochanter. At the insertion, the superficial or bursal surface of the tendon corresponding to the tendon fibers in contact with the subacromial bursa can be distinguished from the deep surface corresponding to the fibers in contact with the glenohumeral joint. A tendon tear may involve partial or total disruption of the tendon fibers and is called full-thickness tear if it affects the entire tendon, and partial-thickness tear if it involves only part of the tendon. Partial-thickness tears of the supraspinatus tendon include lesions of the superficial, deep and central surface or tendon delamination.A contrast enhanced examination requires injection of contrast agent into the joint (arthrography followed by computed tomography (CT) or magnetic resonance imaging (MRI)) to study the deep surface, and injection into the subacromial bursa (bursography followed by CT) to study the superficial surface. MRI and ultrasound (US) examination allow the study of these different tendon layers without the use of contrast agent (which is not possible at CT). PMID:23396264

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

2012-02-01

383

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

PubMed Central

The supraspinatus tendon is composed of 5 different layers consisting of intertwining bundles. On a front portion of the tendon, the layers become coated bundles which insert on the trochanter. At the insertion, the superficial or bursal surface of the tendon corresponding to the tendon fibers in contact with the subacromial bursa can be distinguished from the deep surface corresponding to the fibers in contact with the glenohumeral joint. A tendon tear may involve partial or total disruption of the tendon fibers and is called full-thickness tear if it affects the entire tendon, and partial-thickness tear if it involves only part of the tendon. Partial-thickness tears of the supraspinatus tendon include lesions of the superficial, deep and central surface or tendon delamination. A contrast enhanced examination requires injection of contrast agent into the joint (arthrography followed by computed tomography (CT) or magnetic resonance imaging (MRI)) to study the deep surface, and injection into the subacromial bursa (bursography followed by CT) to study the superficial surface. MRI and ultrasound (US) examination allow the study of these different tendon layers without the use of contrast agent (which is not possible at CT). PMID:23396264

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

2012-01-01

384

Ultrasound characteristics of the patellar and quadriceps tendons among young elite athletes.  

PubMed

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

Visnes, H; Tegnander, A; Bahr, R

2015-04-01

385

In vivo strain of the medial vs. lateral quadriceps tendon in patellofemoral pain syndrome.  

PubMed

Patellofemoral pain (PFP) is thought to be related to patellar maltracking due to imbalances in the knee extensor. However, no study has evaluated the in vivo biomechanical properties of the quadriceps tendon in PFP syndrome. Our purpose was to compare the biomechanical properties of the quadriceps tendons in vivo and noninvasively in patients with PFP syndrome to those of control subjects. The null hypothesis was that the quadriceps tendons of PFP subjects would have significantly decreased strain compared with control subjects. Fourteen subjects (7 control, 7 PFP) performed voluntary ramp isometric contractions to a range of torque levels, while quadriceps tendon elongation was measured using ultrasonography. Tendon strain was calculated for the vastus medialis obliquus (VMO) and vastus lateralis (VL) portion of the quadriceps tendon and compared between subjects (control vs. PFP) and within subjects (VMO vs. VL). PFP subjects showed significantly less VMO tendon strain than control subjects (P<0.001), but there was no difference in VL tendon strain between PFP and control subjects (P=0.100). Relative weakness of the VMO is the most likely cause of the decreased tendon strain seen in subjects with PFP. VMO weakness not only explains the decreased medial tendon strain but also explains the presence of increased lateral patellar translation and lateral patellar spin (distal pole rotates laterally) reported in the literature in this population. This technique can potentially be used in a clinical setting to evaluate quadriceps tendon properties and infer the presence of muscle weakness in PFP. PMID:19541742

Wilson, Nicole A; Press, Joel M; Zhang, Li-Qun

2009-08-01

386

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

PubMed Central

? 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

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

2013-01-01

387

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

PubMed Central

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

Ciarletta, P.; Ben Amar, M.

2009-01-01

388

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

PubMed

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

Ciarletta, P; Ben Amar, M

2009-10-01

389

BME 315 Biomechanics Experiment 4. Fall 2006. Deformation of tendon  

E-print Network

be easily damaged by even the most superficial cuts. To remove the skin, make an incision longitudinally will have the skin attached; skin must be removed before the tendons can be dissected out. Measure the tail are just below the skin but spaced evenly around the outer circumference of the tail. Therefore they can

Lakes, Roderic

390

Laser tissue welding and repair of digital flexor tendons  

NASA Astrophysics Data System (ADS)

Injuries involving division of the flexor tendons of the hand are a common surgical problem. Sutured repairs must be strong enough to withstand early active movement. Experiments were designed to assess the strength of bonds formed between tendon sections as a result of heating (1) under controlled conditions in a water bath and (2) using a carbon dioxide laser (laser tissue welding). The load (N) and stress (N/cm2) required to disrupt thermal bonds between bovine tendon sections heated for 4 minutes in water peaked at 62 degrees Celsius (13N, 11.3N/cm2). Further experiments revealed the optimal time period for heating to be 9 minutes (21.5N, 20.6N/cm2). A threshold effect was apparent at these parameters. The in vitro strength of sutured, laser welded and sutured and laser welded tendon repairs was compared in a rabbit model. Laser welding alone did not produce repairs as strong as sutured repairs. It did, however, augment the strength of sutured repair. This effect was maximal at a power of 0.1 W.

Drew, P. J.; Kiernan, Michael N.; MacGregor, A. D.; Clement, Marc

1996-01-01

391

Orthopedic pitfalls in the ED: Achilles tendon rupture  

Microsoft Academic Search

Achilles tendon rupture is a relatively uncommon occurrence in a general ED population. The history can be subtle, and physical findings may not be clear-cut. Prompt diagnosis and treatment of these injuries, however, is important to improved clinical outcome. The emergency physician needs to remain vigilant for this diagnosis to avoid this orthopedic pitfall. This review article examines the clinical

Jacob Ufberg; Richard A. Harrigan; Thomas Cruz; Andrew D. Perron

2004-01-01

392

Latissimus dorsi tendon transfers for rotator cuff deficiency  

PubMed Central

Purpose: Latissimus dorsi tendon transfers are increasingly being used around the shoulder. We aim to assess any improvement in pain and function following a latissimus dorsi tendon transfer for massive, irreparable postero-superior cuff deficiency. Materials and Methods: At our institution, between 1996 and 2009, 38 latissimus dorsi tendon transfer procedures were performed. Sixteen of these were for massive irreparable rotator cuff deficiency associated with pain and impaired function. All patients were evaluated by means of interview or postal questionnaire and case note review. Pain and function were assessed using the Stanmore percentage of normal shoulder assessment (SPONSA) score, visual analogue scale and Oxford Shoulder Score. Forward elevation was also assessed and a significant improvement was thought to correlate with the success of the procedure at stabilizing the humeral head upon elevation. Results: Mean follow-up time was 70 months. There was a significant reduction in pain on the visual analogue scale from 6.4 to 3.4 (P < 0.05), an improved SPONSA score from 32.5 to 57.5 (P < 0.05), and an improved Oxford Shoulder Score from 40.75 to 29.6 (P < 0.05). Forward elevation improved from 40 preoperatively to 75 postoperatively (P < 0.05). Conclusion: Our results add to the body of evidence that latissimus dorsi tendon transfers for irreparable postero-superior cuff deficiency in selected patients reduce pain and improve shoulder function in the medium term. Level of Evidence: Level 4. PMID:22223959

Donaldson, James; Pandit, Adam; Noorani, Ali; Douglas, Tania; Falworth, Mark; Lambert, Simon

2011-01-01

393

Incidence of symptomatic deep venous thrombosis after Achilles tendon rupture.  

PubMed

Deep venous thrombosis (DVT) is a significant source of morbidity and mortality and is associated with many orthopedic procedures. Previous studies have reported highly variable DVT rates in patients with Achilles tendon rupture undergoing operative and nonoperative treatment. We performed a retrospective chart review for all patients who underwent Achilles tendon repair at our institution from January 2006 to February 2012. Patient data were collected from the electronic medical record system. A total of 115 patients were eligible for the present study. Of these patients, 27 (23.47%) with a surgically treated Achilles tendon rupture developed a symptomatic DVT either while waiting for, or after, surgical intervention, with approximately one third of these diagnosed before surgical intervention. Of the 27 patients with DVT, 3 had a proximal DVT and 24 had a distal DVT. One patient developed a pulmonary embolism. The DVT incidence was greater in the 2 older age groups (40 to 59 and 60 to 79 years) compared individually with the younger age group (20 to 39 years; p < .0026 and p < .0014, respectively). We have shown a high incidence of DVT after Achilles tendon rupture. We recommend a high level of suspicion for the signs and symptoms of DVT during the follow-up period. In addition, patient education and early mobilization should be advocated, especially for patients older than 40 years. Additional randomized controlled trials investigating any benefits to pharmaceutical DVT prophylaxis in this population are needed to establish evidence-based recommendations. PMID:23623625

Makhdom, Asim M; Cota, Adam; Saran, Neil; Chaytor, Ruth

2013-01-01

394

How obesity modifies tendons (implications for athletic activities)  

PubMed Central

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

Abate, Michele

2014-01-01

395

Intraarticular fibroma of the tendon sheath of the knee  

Microsoft Academic Search

Fibroma of the tendon sheath is an uncommon soft-tissue tumor. Intraarticular localization has not been previously reported. The patient presented with unexplained recurrent swelling of the knee not associated with recent trauma. The soft-tissue tumor was identified by magnetic resonance imaging. Arthroscopy confirmed the diagnosis. Arthrotomy was performed because of the large size of the lesion

Halit Pinar; Mustafa zkan; Din zaksoy; U?ur Pabuuo?lu; Devrim Akseki; Osman Karao?lan

1995-01-01

396

Allograft reconstruction for symptomatic chronic complete proximal hamstring tendon avulsion.  

PubMed

Complete proximal hamstring tendon avulsion is an uncommon injury that can cause significant disability in young, athletic individuals. Surgical reattachment is recommended and can be performed on a delayed basis if the tissue is sufficiently mobile. We report 2-year follow up for two cases where interpositional allograft tissue was used for reconstruction because the tendon was too retracted for primary repair. Two 30-year-old patients with complete proximal hamstring avulsion at least 2 years earlier reported severe hamstring weakness and restrictions with respect to sport and recreational activities. Proximal hamstring tendon reconstruction with Achilles tendon allograft was performed for both patients. They were immobilized for 8 weeks with the hip in extension and the knee in flexion using a custom orthosis, followed by physical therapy and weight bearing as tolerated. The patients were followed for over 2 years after the surgery and were evaluated with physical examination, isokinetic strength testing and detailed questions about their function. Following the procedure, both patients returned to a more active lifestyle that was greatly improved with respect to participation in sport and function. This procedure should be considered as a salvage operation as the patients did not return to completely normal function and demonstrated hamstring weakness on the operated side. PMID:18682918

Marx, Robert G; Fives, Gregory; Chu, Samuel K; Daluiski, Aaron; Wolfe, Scott W

2009-01-01

397

Muscle power attenuation by tendon during energy dissipation  

E-print Network

high risk of contraction-associated damage [7,8]. A familiar example is the muscle soreness experiencedMuscle power attenuation by tendon during energy dissipation Nicolai Konow*, Emanuel Azizi, Providence, RI 02912, USA An important function of skeletal muscle is deceleration via active muscle fascicle

Konow, Nicolai

398

Scaphoid Nonunion and Flexor Pollicis Longus Tendon Rupture  

Microsoft Academic Search

Four patients presented with a rupture of the flexor pollicis longus tendon that was associated with a longstanding scaphoid nonunion. A radiocarpal arthrosis was present in 3 of the 4 patients and a dorsiflexed intercalated segment instability deformity was also seen in 3 of the 4 patients. Three patients underwent surgery consisting of an osteosynthesis with an iliac bone graft

Satoru Saitoh; Yukihiko Hata; Narimichi Murakami; Yukio Nakatsuchi; Hiroshi Seki; Kunio Takaoka

1999-01-01

399

Tuberculosis tenosynovitis of the extensor tendons of the wrist  

PubMed Central

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

Mrabet, Dalila; Ouenniche, Kmar; Mizouni, Habiba; Ounaies, Mouna; Khmiri, Chkib; Sahli, Hla; Sellami, Slaheddine

2011-01-01

400

Tendon and neurovascular injuries of the distal radius after pinning with Kirschner Wires: A meta-analysis of cadaveric studies.  

PubMed

Tendon and nerve structures are at risk when displaced fractures of the distal radius are pinned using K-wires. The aim of this meta-analysis (MA) is to examine the published evidence of such complications in cadavers. Eight studies met our inclusion criteria. The meta-analytical results were as follows: (a) 2.87% and 30.5% tendon involvement at the radial styloid process (RSP) and the dorso-radial area of the distal radius, respectively; (b) 3.5% and 1.1% tendon involvement when the percutaneous pinning (PP) and the limited open pinning (LOP) techniques were used, respectively; (c) 16.1% and 3.4% nerve involvement at the RSP and the dorso-radial area of the distal radius, respectively; (d) in 35.7% the nerve was speared and in 64.3% it touched the K-wire at the styloid area; (e) 61.3% cephalic vein involvement in the styloid area; (f) the second branch of the sensitive branch of the radial nerve (SBRN) was the closest to a wire inserted into the RSP; (g) the mean (SD) distance between a branch of the SBRN and a styloid wire was 2.17??0.82 mm. Our results for nerve and tendon injury frequencies in the RSP were close to those in clinical meta-analytical studies, offering an excellent statistical model of evidence synthesis based on cadaveric studies to assess the frequency of such injuries in clinical practice. However, this cadaveric MA yielded more accurate data than the previously reported clinical MA in assessing the real risk of injury of such structures in the distal radius in terms of their proximity to the inserted K-wires. Clin. Anat. 28:545-550, 2015. 2015 Wiley Periodicals, Inc. PMID:25759165

Yammine, Kaissar; Rafi, Sidiqa M; Furhad, Sadia

2015-05-01

401

ggstThe role of tendon microcirculation in Achilles and patellar tendinopathy  

PubMed Central

Tendinopathy is of distinct interest as it describes a painful tendon disease with local tenderness, swelling and pain associated with sonographic features such as hypoechogenic texture and diameter enlargement. Recent research elucidated microcirculatory changes in tendinopathy using laser Doppler flowmetry and spectrophotometry such as at the Achilles tendon, the patellar tendon as well as at the elbow and the wrist level. Tendon capillary blood flow is increased at the point of pain. Tendon oxygen saturation as well as tendon postcapillary venous filling pressures, determined non-invasively using combined Laser Doppler flowmetry and spectrophotometry, can quantify, in real-time, how tendon microcirculation changes over with pathology or in response to a given therapy. Tendon oxygen saturation can be increased by repetitive, intermittent short-term ice applications in Achilles tendons; this corresponds to 'ischemic preconditioning', a method used to train tissue to sustain ischemic damage. On the other hand, decreasing tendon oxygenation may reflect local acidosis and deteriorating tendon metabolism. Painful eccentric training, a common therapy for Achilles, patellar, supraspinatus and wrist tendinopathy decreases abnormal capillary tendon flow without compromising local tendon oxygenation. Combining an Achilles pneumatic wrap with eccentric training changes tendon microcirculation in a different way than does eccentric training alone; both approaches reduce pain in Achilles tendinopathy. The microcirculatory effects of measures such as extracorporeal shock wave therapy as well as topical nitroglycerine application are to be studied in tendinopathy as well as the critical question of dosage and maintenance. Interestingly it seems that injection therapy using color Doppler for targeting the area of neovascularisation yields to good clinical results with polidocanol sclerosing therapy, but also with a combination of epinephrine and lidocaine. PMID:18447938

Knobloch, Karsten

2008-01-01

402

Identification of tendon stem\\/progenitor cells and the role of the extracellular matrix in their niche  

Microsoft Academic Search

The repair of injured tendons remains a great challenge, largely owing to a lack of in-depth characterization of tendon cells and their precursors. We show that human and mouse tendons harbor a unique cell population, termed tendon stem\\/progenitor cells (TSPCs), that has universal stem cell characteristics such as clonogenicity, multipotency and self-renewal capacity. The isolated TSPCs could regenerate tendon-like tissues

Yanming Bi; Driss Ehirchiou; Tina M Kilts; Colette A Inkson; Mildred C Embree; Wataru Sonoyama; Li Li; Arabella I Leet; Byoung-Moo Seo; Li Zhang; Songtao Shi; Marian F Young

2007-01-01

403

Accelerated corrosion testing, evaluation and durability design of bonded post-tensioned concrete tendons  

NASA Astrophysics Data System (ADS)

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.

Salas Pereira, Ruben Mario

2003-06-01

404