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Topic:Tendons
Tendons in horses are fibrous connective tissues that attach muscles to bones, facilitating movement and providing stability to the musculoskeletal system. They are composed primarily of collagen fibers, which confer strength and flexibility, allowing horses to perform various physical activities. Equine tendons are subject to significant mechanical stress during locomotion, making them susceptible to injury, particularly in performance horses. Common tendon injuries include strains, tears, and tendinitis, which can impact a horse's mobility and performance. This page compiles peer-reviewed research studies and scholarly articles that explore the structure, function, and pathology of tendons in horses, as well as advancements in diagnostic and therapeutic approaches for tendon injuries.
Tenoscopic anatomy of the equine carpal flexor synovial sheath. To describe the tenoscopic anatomy of the carpal sheath of the flexor tendons (carpal sheath) viewed from a lateral approach. Methods: Tenoscopic observation of structures within the carpal sheath subsequently confirmed by dissection. Methods: 12 equine cadaveric forelimbs. Methods: The limbs were positioned lateral side up with the carpus slightly flexed. After distention of the carpal sheath, a portal for the arthroscope was made approximately 3 cm proximal to the distal radial physis and 2.5 cm caudal to the radius between the tendons of the ulnaris lateralis and lateral digital extensor mu...
Effects of experimental desmotomy on material properties and histomorphologic and ultrasonographic features of the accessory ligament of the deep digital flexor tendon in clinically normal horses. To evaluate posttrauma biomechanical behavior of the scar attributable to desmotomy of the accessory ligament of the deep digital flexor tendon (AL-DDFT), compared with the histomorphologic and ultrasonographic appearance. Methods: 5 Standardbred trotters. Methods: Gross appearance, length, cross-sectional area (CSA), in vitro material properties, and ultrasonographic and histomorphologic features were studied 6 months after desmotomy. Tensile tests were conducted, with forces and elongation simultaneously recorded. Surgically treated limbs were compared with nontreated contralateral limbs. Re...
Long-term consequences of experimental desmotomy of the accessory ligament of the deep digital flexor tendon in adult horses. To evaluate clinical and biomechanical consequences of desmotomy of the accessory ligament (AL) of the deep digital flexor tendon (DDFT) of equine forelimbs and determine whether this procedure is a viable treatment for chronic desmitis of the AL-DDFT. Methods: 6 adult Standardbred trotters. Methods: Biomechanical recordings obtained before and 6 months after desmotomy were compared. Walk and trot joint angles, ground reaction forces, peak joint moments, and tendon forces were assessed. Results: Within 10 days after surgery, all horses were sound at a trot. Swelling, increased carpal flexion i...
The distribution of cartilage oligomeric matrix protein (COMP) in tendon and its variation with tendon site, age and load. A protein prominent in guanidine hydrochloride extracts of adult bovine and equine digital flexor tendons was confirmed to be Cartilage Oligomeric Matrix Protein (COMP) by non-reducing and reducing SDS-PAGE, reaction with rabbit anti-COMP polyclonal antiserum on Western blots, trypsin digestion followed by HPLC on a C2/C18 column, and identification of COMP mRNA from tendon on Northern blots. Immunohistochemistry and Western blots of extracts showed COMP to be present in all regions of digital flexor tendons. Equine tendon COMP was purified by ion exchange chromatography and gel filtration and...
Exercise-related alterations in crimp morphology in the central regions of superficial digital flexor tendons from young thoroughbreds: a controlled study. Injury to the core of the mid-metacarpal region of the superficial digital flexor tendon in Thoroughbred racehorses is a very frequent but poorly understood condition. It has been suggested that subclinical changes induced by galloping exercise weaken the collagen in this region of the tendon, predisposing it to rupture. The longitudinally arranged collagen fibrils in tendon follow a planar waveform, termed the crimp. Fibril bundles with a smaller crimp angle fail at a lower level of strain than those with a larger crimp angle. This study tested the hypothesis that a specific 18 month exercise...
Endoscopic examination of the carpal flexor tendon sheath in horses. This study was undertaken to design a safe technique to examine the carpal flexor tendon sheath (carpal sheath) of horses endoscopically, using an arthroscope. The limbs from 15 horses were used to study the normal anatomy of the carpal sheath and related structures, establish a safe approach and endoscopic technique, and determine the normal endoscopic appearance of the sheath. Major arteries, veins and nerves, present within and around the sheath, left few 'safe' areas to insert the endoscope. Several portals were assessed and a distal lateral approach was found to be safest and to allow ade...
Gross and ultrasonographic anatomy of the carpal flexor tendon sheath in horses. This study was undertaken to establish the gross anatomy and the ultrasonographic appearance of the carpal digital flexor tendon sheath (carpal sheath) and the palmar carpal region in normal horses. The isolated forelimbs from 15 horses were used to study the morphology of the sheath and associated structures, including a detailed study of the location of the main blood vessels and nerves in that region. These limbs and the forelimbs of five live, sound horses were also examined ultrasonographically. The examination yielded good soft tissue detail of the tendons and ligaments, synovial and per...
Exercise modifies the age-related change in crimp pattern in the core region of the equine superficial digital flexor tendon. One of the current concepts with regard to equine superficial digital flexor tendonitis is that cumulative subclinical microscopic damage weakens the structure, predisposing the tendon to partial or complete rupture. This microtrauma is likely to affect the waveform or crimp of the collagen fibrils, which are the units of tensile strength. Collagen fibril crimp morphology characteristics were determined in superficial digital flexor tendons of 18 horses presented for necropsy. Horses were separated into exercised (n = 9) and non-exercised groups (n = 9), based on recent function. Five of the e...
[Scanning electron microscopic investigations on the anatomy of the fetlock joint in horses]. Striking synovial structures were taken and their surface was investigated by scanning electron microscopy. Depending where the probes were taken from, the stratum synovial was arranged in a different way. The synovial intima seems to miss under the tendon of the long/commune extensor muscle, the collateral ligaments and the sesamoidean collateral ligaments. That is why the subsynovial tissue forms the superficial layer. The surface of the probes taken sidewards to the tendon of the extensor muscle and of the synovial fold, which is situated between the metacarpus/metatarsus and the proximal p...
The effect of exercise-induced localised hyperthermia on tendon cell survival. Tendons that store energy during locomotion, such as the equine superficial digital flexor tendon (SDFT) and human Achilles tendon, suffer a high incidence of central core degeneration which is thought to precede tendon rupture. Although energy storage contributes to the efficiency of locomotion, tendons are not perfectly elastic and some energy is lost in the form of heat. Recent studies have shown that the central core of equine SDFT reaches temperatures as high as 45 degrees C during high-speed locomotion. In this study, we test the hypothesis that hyperthermia causes tendon cell death and ...
Repair of a deep digital tendon deficit in a horse using a polypropylene implant. A yearling horse was treated for a chronic wound with a 4 cm deficit in the deep digital tendon. The gap in the tendon was bridged with paired polypropylene braided implants designed for use as a ligament augmentation device. Uncomplicated healing and return to function occurred.
Mechanical properties of pathological equine superficial digital flexor tendons. The objective of this study was to mechanically characterise superficial digital flexor tendon (SDFT) lesions. Eight pathological SDFTs, isolated from 6 adult horses, were tested in traction until rupture (at 1 mm/s). The stresses and strains simultaneously undergone by each of the 7 segments of a tendon were determined throughout the test, and the modulus of elasticity of each segment was evaluated from the segmental stress-strain curve thus obtained. These mechanical data were compared to those obtained on 10 normal SDFTs. After the test, the tendinous segments were submitted to a histologic...
Tendonitis of the branches of insertion of the superficial digital flexor tendon in horses. To describe clinical findings, ultrasonographic features and outcome of injury to the branches of insertion of the superficial digital flexor (SDF) tendon in horses. Methods: Retrospective study of 14 cases. Methods: Fourteen Thoroughbred horses with tendonitis affecting the branches of insertion of the SDF tendon were examined for lameness, location and amount of swelling, and the presence of other musculoskeletal abnormalities. The flexor tendons were assessed by ultrasonographic examination, and recommendations were made for management of the cases. Outcome was assessed by re-examination of...
Effect of maturation and aging on the histomorphometric and biochemical characteristics of equine superficial digital flexor tendon. To assess tendon morphology and non-reducible crosslink concentration, and associations of these findings with horse age and previously reported mechanical and ultrasonographic findings. Methods: Superficial digital flexor tendon samples were obtained from 23 horses aged 2 to 23 years. The tendons had undergone ultrasonography and were submitted to biomechanical testing in the physiologic range prior to sample acquisition. Methods: Samples were sectioned in a transverse plane; then dorsal, palmar, central, lateral, and medial regions were evaluated for fascicle cross-sectional area (CSA), sept...
Oxidative energy metabolism in equine tendon cells. Hypoxia has been suggested as a possible cause of tissue degeneration and subsequent rupture in equine tendons. To determine whether low oxygen tension is likely to be detrimental to tendon cell function, experiments were designed to investigate oxidative energy metabolism in freshly isolated and cultured equine tendon cells. Freshly isolated tenocytes and cultured fibroblasts possessed activities of the mitochondrial enzyme citrate synthase similar to those of other mammalian cells, with well defined oxidative metabolism. D-[6(-14)C]-glucose oxidation was measurable in both freshly isolated a...
Comparison of collagen fibril populations in the superficial digital flexor tendons of exercised and nonexercised thoroughbreds. This study was undertaken to test the hypothesis that collagen fibrils, the submicroscopic units of strength in tendon, would hypertrophy in response to a specific defined training programme. Fibril diameters were measured in central and peripheral regions of superficial digital flexor tendon (SDFT) samples from five 18-month-old horses which underwent a subsequent 18 month training programme and 6 age- and sex-matched controls. Central region fibrils from the trained horses had a mass-average diameter (MAD) of 105.3 nm, which was significantly lower (P < 0.01) than that of 131.7 nm for the...
Age-related differences in collagen crimp patterns in the superficial digital flexor tendon core region of untrained horses. To measure collagen fibril crimp angles and lengths as well as collagen fibril mass-average diameters in central and peripheral regions of the superficial digital flexor tendon of wild horses, to ascertain any age-related changes in either region in the absence of imposed galloping exercise. Methods: Measurements from a random cull of wild horses. Methods: Superficial digital flexor tendon samples were taken from 23 wild horses ranging in age from two to ten years. Methods: Horses were divided into 'young' (< 5 years, n = 10), 'middle-aged' (5 to < 10 years, n = 9) and 'ol...
Biochemical and site-specific effects of insulin-like growth factor I on intrinsic tenocyte activity in equine flexor tendons. To examine the site-specific and dose-dependent effects of insulin-like growth factor I (IGF-I) on normal equine tendon in vitro. Methods: Superficial digital flexor tendon explants derived from a euthanatized 3-year-old horse. Methods: Explants in culture were treated with 0, 100, 250, or 500 ng of IGF-I/ml for 14 days with an end-stage radiolabel of 20 microCi of [3H]proline/ml or 5 microCi of [3H]thymidine/ml. The tendon tissues were then analyzed biochemically for hydroxyproline content by reverse-phase high-performance liquid chromatography, DNA content by fluorometry, and glycosaminoglyc...
An age-related study of morphology and cross-link composition of collagen fibrils in the digital flexor tendons of young thoroughbred horses. The superficial digital flexor tendon is the most commonly injured tendon in the racing Thoroughbred. Despite the clinical significance of this structure, only limited data exist regarding normal age-related morphology of the tensile units, the collagen fibrils. The age at which these collagen fibrils become mature in composition and structure may be of importance. Consequently, the association of age and collagen fibril crosslink composition, diameter distribution and crimp morphology in the superficial and deep digital flexor tendons of Thoroughbreds up to and including three years of age ha...
Treatment of acute superficial digital flexor tendon injury in horses with polysulphated glycosaminoglycan. Horses with acute injuries of the superficial digital flexor tendon were treated with a course of seven intramuscular injections of 500 mg of polysulphated glycosaminoglycan at four-day intervals. Clinical assessments of the lesions were made by a veterinary surgeon at the time of each injection and 14 and 28 days after the last injection. A total of 150 courses of the drug were administered and adequately completed assessment forms were returned for 80 cases. Long-term follow-up data were obtained for 19 cases. The subjective assessments by the veterinary surgeons showed that in 80 per cent o...
Segmental variations of in vitro mechanical properties in equine superficial digital flexor tendons. To determine the local variations of mechanical properties of the equine superficial digital flexor tendon (SDFT). Methods: 10 SDFT of adult horses, selected for absence of abnormality. Methods: Needles (with a dark marker at both ends) pinned perpendicularly through each tendon to delimit 7 segments. Each tendon was tested in traction until rupture; test was filmed, using an 8-mm video camera. For each image, the coordinates of the center of mass of each marker and the corresponding force were registered. The third-degree polynomial that best fits the stress-strain curve thus obtained was cal...
Comparison of media and sera used for in vitro culture of equine superficial digital flexor tendon explants. To compare the effects of different commercial nutrient media and sera on protein synthesis and maintenance of cellular density in cultures of the equine superficial digital flexor tendon (SDFT). Methods: 8 healthy 2- to 4-year-old horses. Methods: First Dulbecco's modified Eagle's medium, Ham's F12 nutrient mixture, RPMI 1640 medium, minimum essential medium with Earle's salts, minimum essential medium with Hanks' salts, and a Dulbecco's modified Eagle's medium/Ham's F12 nutrient mixture with 10% fetal bovine serum (FBS) were compared. Then FBS, fetal equine serum, and donor horse serum, each...
Evaluation of an autologous tendon graft repair method for gap healing of the deep digital flexor tendon in horses. A sutured tenorrhaphy technique that incorporated an autologous tendon graft was compared mechanically and histologically with a sutured tenorrhaphy at 6, 12, and 24 weeks after repair. Tenorrhaphy was performed in the forelimb tendon of the deep digital flexor muscle and the graft was taken from the hindlimb tendon of the lateral digital extensor muscle; one forelimb site included the graft, whereas the other forelimb site was not grafted. Tenotomies were made immediately proximal to the insertion of the accessory ligament into the tendon of the deep digital flexor muscle. Grafted and nongraf...
Ultrasonic properties of tendon: velocity, attenuation, and backscattering in equine digital flexor tendons. Ultrasound velocity, attenuation, and backscattering were measured in vitro in samples of equine digital flexor tendon sandwiched between plane, parallel rexolite buffer rods. The buffer rods were coupled to transmitting and receiving transducers (nominally 10 MHz) mounted in-line and facing one another on the jaws of a digital caliper. Six superficial digital flexor (SDF) tendons and six deep digital flexor (DDF) tendons were measured in three orthogonal directions: along the long axis of the tendon (D), and across the tendon in the dorsal-volar (C), and lateral (L) directions. Substantial an...
Tendon strain in the forelimbs as a function of gait and ground characteristics and in vitro limb loading in ponies. Strains in the tendons of the m. flexor digitalis superficialis (superficial digital flexor, SDFT) and m. flexor digitalis profundus (deep digital flexor, DDFT) tendons, the accessory ligament of the deep digital flexor muscle (inferior check ligament, ICL) and the m. interosseus medius (suspensory ligament, SL) of 5 ponies were recorded at the walk and trot using mercury-in-silastic strain gauges (MISS), on a hard surface (brick pavement) and on sand. The horses were shod with normal, flat shoes. On pavement, strain in the SDFT, DDFT and SL increased significantly from the walk (2.19%, 1.15% ...
Influence of shoeing on ground reaction forces and tendon strains in the forelimbs of ponies. Strains in the superficial digital flexor tendon (SDFT), deep digital flexor tendon (DDFT), accessory ligament of the deep digital flexor muscle (inferior check ligament [ICL]) and the interosseus medius muscle (suspensory ligament [SL]) in the right forelimb of 5 ponies were measured using mercury-in-silastic strain gauges a few hours after implantation. Tendon strains were recorded at the walk with normal flat shoes, egg-bar shoes, a 7 degrees increased hoof angle accomplished by application of a heel-wedge and a 7 degrees decreased hoof angle using a toe-wedge, consecutively. Ground reactio...
Load redistribution after desmotomy of the accessory ligament of the deep digital flexor tendon in adult horses. An analysis of joint moments was used to study the biomechanical implications, load redistribution and kinematic pattern following desmotomy of the accessory ligament of the deep digital flexor tendon (AL) in adult horses. Recordings of 6 sound horses were made before and 10 days after desmotomy of the AL of the right forelimb at the walk and the trot. Kinematic recordings of the right forelimb and the left distal forelimb were made using the CODA-3 system. Kinetic recordings of the ground reaction forces in both forelimbs were made using a Kistler force plate simultaneously with the kinematic...
Factors affecting the ultrasonic properties of equine digital flexor tendons. The velocity, attenuation and apparent backscattering coefficient of 6-11-MHz ultrasound were measured in three orthogonal directions in equine deep digital flexor (DDF) and superficial digital flexor (SDF) tendons at 0 degree C. Ultrasonic measurements were examined for correlation with tendon water, collagen, DNA and glycosaminoglycans contents, determined by chemical analyses and with structure observed by scanning electron microscopy. The SDF tendon contained more water, more DNA (i.e., more cells), less collagen and less glycosaminoglycans and exhibited lower velocities and attenuations t...
