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.
Russell JW, Hall MS, Kelly GM.A 3-year-old Thoroughbred gelding was presented with a grade 3/5 lameness of the right forelimb and effusion of the extensor carpi radialis tendon sheath (ECRTS). Radiographic and ultrasonographic examinations revealed an osteochondroma on the cranial aspect of the distal radius projecting into the fibrous lining of the ECRTS. An open surgical approach was used to remove the osteochondroma and some of the proliferative synovial tissue. Conclusions: Six months after surgery the clinical signs had resolved and the horse raced successfully.
Bavin EP, Atkinson F, Barsby T, Guest DJ.The transcription factor scleraxis is required for tendon development and is upregulated during embryonic stem cell (ESC) differentiation into tenocytes. However, its role beyond early embryonic development is not defined. We utilized a short hairpin RNA to knock down scleraxis expression in ESCs and adult and fetal tenocytes. No effect on growth or morphology was observed in two-dimensional cultures. However, scleraxis knockdown in fetal tenocytes significantly reduced COL1A1, COMP, and SOX9 gene expression. Scleraxis knockdown in adult tenocytes had no effect on the expression of these genes...
Tamura N, Kuroda T, Kotoyori Y, Fukuda K, Nukada T, Kato T, Kuwano A, Kasashima Y.Sonoelastography can assess the inner stiffness of tissues. Sonoelastographic evaluation of injured equine superficial digital flexor tendons (SDFTs) is considered to be useful for assessing the stiffness of a lesion even during late-stage rehabilitation. The purpose of this study was to investigate and compare the sonoelastographic appearance of injured SDFTs over time from the onset of the injury. Eighteen horses were classified into three groups according to the length of time from injury onset: group A, within two weeks after injury; group B, approximately five months after injury; and gro...
Kuemmerle JM, Theiss F, Okoniewski MJ, Weber FA, Hemmi S, Mirsaidi A, Richards PJ, Cinelli P.Although several tendon-selective genes exist, they are also expressed in other musculoskeletal tissues. As cell and tissue engineering is reliant on specific molecular markers to discriminate between cell types, tendon-specific genes need to be identified. In order to accomplish this, we have used RNA sequencing (RNA-seq) to compare gene expression between tendon, bone, cartilage and ligament from horses. We identified several tendon-selective gene markers, and established eyes absent homolog 2 () and a G-protein regulated inducer of neurite outgrowth 3 () as specific tendon markers using RT-...
Evans CH, Chevalier X, Wehling P.Autologous conditioned serum was developed in the mid 1990s as an expeditious, practical, and relatively inexpensive means of generating the interleukin-1 receptor antagonist, a naturally occurring inhibitor of the cytokine interleukin-1. The latter is thought to be an important mediator of inflammation, pain, and tissue destruction in musculoskeletal conditions. ACS has been widely and successfully used in the local treatment of human and equine osteoarthritis and radicular compression; it has also shown promise in treating tendinopathies, muscle injuries, and tunnel widening after reconstruc...
Garvican ER, Salavati M, Smith RKW, Dudhia J.The purpose of this study was to investigate the effect of normal synovial fluid (SF) on exposed endogenous tendon-derived cells (TDCs) and engrafted mesenchymal stem cells (MSCs) within the tendon extracellular matrix. Methods: Explants from equine superficial digital flexor (extra-synovial) and deep digital flexor tendons (DDFTs) from the compressed, intra-synovial and the tensile, extra-synovial regions were cultured in allogeneic or autologous SF-media. Human hamstring explants were cultured in allogeneic SF. Explant viability was assessed by staining. Proliferation of equine monolayer MSC...
Spriet M, Espinosa P, Kyme AZ, Stepanov P, Zavarzin V, Schaeffer S, Katzman SA, Galuppo LD, Beylin D.Positron emission tomography (PET) is a highly sensitive, noninvasive imaging technique for quantifying biological functions of tissues. However, at the time of this study, PET imaging applications had not been reported in the horse. The aim of this exploratory study was to determine whether a portable high-resolution PET scanner could be used to image the equine distal limb. Images of the front feet and fetlocks of three research horses, with known lesions localized to the distal front limbs, were acquired under general anesthesia after administration of 18 F-fluorodeoxyglucose (18 F-FDG), wi...
Sherlock CE, Mair TS.Recognition of artefacts is an essential component of the accurate interpretation of diagnostic images. This study aimed to investigate the presence of magic angle effect in the superficial digital flexor tendon (SDFT) in the equine proximal pastern region. The proximal pastern of four cadaver limbs was imaged using a 0.27 Tesla magnet with high-resolution sequences that are commonly utilised in clinical equine practice. The limbs were imaged in a neutral position and positions that simulated the horse 'leaning in', 'leaning out' and having internal and external rotation of the distal limb. Si...
Scharf A, Holmes SP, Thoresen M, Mumaw J, Stumpf A, Peroni J.Ultrasound-guided intralesional injection of mesenchymal stem cells (MSCs) is held as the benchmark for cell delivery in tendonitis. The primary objective of this study was to investigate the immediate cell distribution following intralesional injection of MSCs. Unilateral superficial digital flexor tendon (SDFT) lesions were created in the forelimb of six horses and injected with 10 × 10 MSCs labeled with superparamagnetic iron oxide nanoparticles (SPIOs) under ultrasound guidance. Assays were performed to confirm that there were no significant changes in cell viability, proliferation, migra...
Geburek F, Gaus M, van Schie HT, Rohn K, Stadler PM.Regenerative and anti-inflammatory effects on tendinopathies have been attributed to blood-derived biologicals. To date the evidence for the efficacy of autologous platelet-rich plasma (PRP) treatment of naturally occurring equine tendinopathies is limited. The purpose of this placebo-controlled clinical trial was to describe the effect of a single treatment of equine superficial digital flexor tendon (SDFT) disease with PRP on clinical and ultrasonographic parameters. Twenty horses with naturally occurring tendinopathies of forelimb SDFTs were randomly assigned to the PRP-treated group (n =...
Duesterdieck-Zellmer KF, Larson MK, Plant TK, Sundholm-Tepper A, Payton ME.OBJECTIVE To measure penetration efficiencies of low-level laser light energy through equine skin and to determine the fraction of laser energy absorbed by equine digital flexor tendons (superficial [SDFT] and deep [DDFT]). SAMPLE Samples of skin, SDFTs, and DDFTs from 1 metacarpal area of each of 19 equine cadavers. PROCEDURES A therapeutic laser with wavelength capabilities of 800 and 970 nm was used. The percentage of energy penetration for each wavelength was determined through skin before and after clipping and then shaving of hair, through shaved skin over SDFTs, and through shaved skin,...
Aldrich ED, Goodrich LR, Monahan MK, Conway JD, Valdés-Martínez A.Injury to the tendons and ligaments of the equine stifle is a common cause of lameness in horses. Individual radiographic localisation of each tendon and ligament of the stifle has not been previously reported or demonstrated in multiple radiographic projections. Objective: To create a series of radiographs identifying the origins and/or insertions of the tendons and ligaments of the equine stifle. Methods: Descriptive study of radiographic anatomy. Methods: The location of all entheses were determined by gross dissection. The proximal tibia and fibula, distal femur, patella and menisci were i...
DiGiovanni DL, Rademacher N, Riggs LM, Baumruck RA, Gaschen L.Palmar/plantar annular desmitis is a common disease that may be associated with adhesions and structures affecting the flexor tendons, which requires tenoscopy to diagnose. The purpose of this descriptive study was to develop a dynamic sonographic technique for evaluating the motion of normal equine flexor tendons in relation to the palmar/plantar annular ligament and to compare findings with horses previously diagnosed with palmar/plantar annular desmitis. Ten healthy adult horses were examined prospectively and the images of four horses diagnosed with palmar/plantar annular desmitis were ret...
Brokken MT, Schneider RK, Roberts GD, Holmes SP, Gavin PR, Sampson SN, Farnsworth KD, Dahlgren LA.To evaluate the effects of a new microfracture and ligament splitting procedure on ligament healing and to examine the usefulness of magnetic resonance (MR) imaging for monitoring ligament healing over time using a collagenase model of hind limb proximal suspensory desmitis. Methods: Experimental in vivo study. Methods: Healthy adult horses (n=6). Methods: Horses were free of lameness with normal hind limb proximal suspensory ligaments (PSL). The origin of both hind limb PSL was injected with collagenase and underwent MR imaging 2 weeks later, followed by the microfracture and ligament splitti...
Burk J, Plenge A, Brehm W, Heller S, Pfeiffer B, Kasper C.Tendon and ligament pathologies are still a therapeutic challenge, due to the difficulty in restoring the complex extracellular matrix architecture and biomechanical strength. While progress is being made in cell-based therapies and tissue engineering approaches, comprehensive understanding of the fate of progenitor cells in tendon healing is still lacking. The aim of this study was to investigate the effect of decellularized tendon matrix and moderate cyclic stretching as natural stimuli which could potentially direct tenogenic fate. Equine adipose-derived mesenchymal stromal cells (MSC) were...
Witte S, Dedman C, Harriss F, Kelly G, Chang YM, Witte TH.Superficial digital flexor (SDF) tendonitis is a common injury in Thoroughbred racehorses. Injuries require prolonged rehabilitation, with unpredictable outcomes and a high incidence of re-injury. This observational case-control study aimed to compare race outcomes after commonly advocated treatments for tendon healing. Clinical and racing records were evaluated for 127 National Hunt racehorses treated between 2007 and 2011 for an SDF tendon injury. Two age- and sex-matched control horses were selected for each case horse to analyse the effect on post-injury racing outcomes of pre-injury data,...
Bottagisio M, Pellegata AF, Boschetti F, Ferroni M, Moretti M, Lovati AB.Tendon ruptures and/or large losses remain to be a great clinical challenge and often require full replacement of the damaged tissue. The use of auto- and allografts or engineered scaffolds is an established approach to restore severe tendon injuries. However, these grafts are commonly related to scarce biocompatibility, site morbidity, chronic inflammation and poor biomechanical properties. Recently, the decellularisation techniques of allo- or xenografts using specific detergents have been studied and have been found to generate biocompatible substitutes that resemble the native tissue. This...
Burk J, Berner D, Brehm W, Hillmann A, Horstmeier C, Josten C, Paebst F, Rossi G, Schubert S, Ahrberg AB.Tendon disease has been treated with multipotent mesenchymal stromal cells (MSCs) in the equine large-animal model with promising success. The aim of this study was to gain more insight into the fate and biodistribution of MSCs after local application into tendon lesions by long-term cell tracking in this large-animal model. Superficial digital flexor tendon lesions were induced in all limbs in six horses and injected with 10106 Molday ION Rhodamine B-labeled MSCs suspended in serum or serum alone. Follow-up was performed using low-field magnetic resonance imaging (MRI), flow cytometry, and hi...
Mizobe F, Okada J, Shinzaki Y, Nomura M, Kato T, Yamada K, Spriet M.Desmitis of the oblique distal sesamoidean ligaments (ODSL) is caused by hyperextension of the metacarpophalangeal/metatarsophalangeal joint and has been described as a significant cause of lameness in racehorses. In this study, three Thoroughbred racehorses (age range: 3-6 years) were diagnosed with desmitis of the forelimb ODSL using standing low-field magnetic resonance imaging (sMRI). Radiography and ultrasonography were inconclusive with regard to a definitive diagnosis. For all horses, the sMRI characteristics included increased signal intensity within the medial ODSL on T1-weighted grad...
Griffon DJ, Cho J, Wagner JR, Charavaryamath C, Wei J, Wagoner Johnson A.Chitosan opens new perspectives in regenerative medicine as it enhances the properties of mesenchymal stem cells (MSCs) through formation of spheroids. Hypoxia has also been proposed to enhance stemness and survival of MSCs after in vivo implantation. These characteristics are relevant to the development of an off-the-shelf source of allogenic cells for regenerative therapy of tendinopathies. Umbilical cord-derived MSCs (UCM-MSCs) offer an abundant source of immature and immunoprivileged stem cells. In this study, equine UCM-MSCs (eqUCM-MSCs) conditioned for 3 and 7 days on chitosan films at 5...
Thorpe CT, Riley GP, Birch HL, Clegg PD, Screen HRC.Tendon is composed of rope-like fascicles, bound together by interfascicular matrix (IFM). Our previous work shows that the IFM is critical for tendon function, facilitating sliding between fascicles to allow tendons to stretch. This function is particularly important in energy storing tendons, which experience extremely high strains during exercise, and therefore require the capacity for considerable inter-fascicular sliding and recoil. This capacity is not required in positional tendons. Whilst we have previously described the quasi-static properties of the IFM, the fatigue resistance of the...
Choi RK, Smith MM, Martin JH, Clarke JL, Dart AJ, Little CB, Clarke EC.Both mechanical and structural properties of tendon change after injury however the causal relationship between these properties is presently unclear. This study aimed to determine the extent of biomechanical change in post-injury tendon pathology and whether the sulphated glycosaminoglycans (glycosaminoglycans) present are a causal factor in these changes. Equine superficial digital flexor tendons (SDF tendons) were surgically-injured in vivo (n=6 injured, n=6 control). Six weeks later they were harvested and regionally dissected into twelve regions around the lesion (equal medial/lateral, pr...
Russell JW, Russell TM, Vasey JR, Hall MS.To evaluate a treatment protocol whereby superficial digital flexor (SDF) tendonitis in Thoroughbred and Standardbred racehorses was treated with autologous bone marrow aspirate (ABMA) obtained from the sternebrae. This treatment was combined with desmotomy of the accessory ligament of the SDF tendon (DAL-SDFT) in selected cases. Medical records of 105 horses treated using the reported protocol were reviewed. Signalment, history and details of treatment were recorded. Racing records were reviewed and performance recorded. Of Thoroughbreds, 82 per cent had one or more starts within the follow-u...
Jordana M, Cornillie P, Oosterlinck M, Simoens P, Pille F, Martens A.During endoscopy (tenoscopy) of the distal aspect of the equine digital flexor tendon sheath (DFTS), the digital manica flexoria can be visualized connecting the distal branches of the superficial digital flexor tendon. However, this structure has been inconsistently described and variably named in the veterinary literature. The objectives of this study were to describe the presence, configuration and variability of the digital manica flexoria in the equine distal limb. Dissection of 144 equine cadaveric limbs revealed the presence of this structure in all the feet, although different types an...
Thorpe CT, Karunaseelan KJ, Ng Chieng Hin J, Riley GP, Birch HL, Clegg PD, Screen HR.Although the predominant function of all tendons is to transfer force from muscle to bone and position the limbs, some tendons additionally function as energy stores, reducing the energetic cost of locomotion. To maximise energy storage and return, energy-storing tendons need to be more extensible and elastic than tendons with a purely positional function. These properties are conferred in part by a specialisation of a specific compartment of the tendon, the interfascicular matrix, which enables sliding and recoil between adjacent fascicles. However, the composition of the interfascicular matr...
Durgam SS, Stewart AA, Sivaguru M, Wagoner Johnson AJ, Stewart MC.Tendinitis is a common and a performance-limiting injury in athletes. This study describes the value of intralesional tendon-derived progenitor cell (TDPC) injections in equine flexor tendinitis. Collagenase-induced tendinitis was created in both front superficial digital flexor (SDF) tendons. Four weeks later, the forelimb tendon lesions were treated with 1 × 10 autogenous TDPCs or saline. Tendinitis was also induced by collagenase in one hind SDF tendon, to study the survival and distribution of DiI-labeled TDPCs 1, 2, 4, and 6 weeks after injection. The remaining normal tendon was used...
Youngstrom DW, LaDow JE, Barrett JG.Tendons are frequently damaged and fail to regenerate, leading to pain, loss of function, and reduced quality of life. Mesenchymal stem cells (MSCs) possess clinically useful tissue-regenerative properties and have been exploited for use in tendon tissue engineering and cell therapy. However, MSCs exhibit phenotypic heterogeneity based on the donor tissue used, and the efficacy of cell-based treatment modalities may be improved by optimizing cell source based on relative differentiation capacity. Equine MSCs were isolated from bone marrow (BM), adipose (AD), and tendon (TN), expanded in monola...
Lange-Consiglio A, Perrini C, Tasquier R, Deregibus MC, Camussi G, Pascucci L, Marini MG, Corradetti B, Bizzaro D, De Vita B, Romele P, Parolini O....Administration of horse amniotic mesenchymal cells (AMCs) and their conditioned medium (AMC-CM) improves the in vivo recovery of spontaneous equine tendon lesions and inhibits in vitro proliferation of peripheral blood mononuclear cells (PBMC). This process may involve microvesicles (MVs) as an integral component of cell-to-cell communication during tissue regeneration. In this study, the presence and type of MVs secreted by AMCs were investigated and the response of equine tendon cells to MVs was studied using a dose-response curve at different concentrations and times. Moreover, the ability ...
Molle S.The Kinesio taping method was developed in Japan for use in humans in 1979. The use of complementary therapies is becoming common in equine athletes and the discovery of Kinesio taping potential brought it into the animal world. Kinesio taping can be used to treat a wide range of clinical conditions, from tendon injuries to neurologic disorders and from muscle contractures to postural insufficiencies. Its use in veterinary medicine is promising, but relies heavily on evidence-based clinical reports. Further scientific research is needed to fully understand the real effectiveness of application...
Zamboulis DE, Marr N, Lenzi L, Birch HL, Screen HRC, Clegg PD, Thorpe CT.Energy storing tendons such as the human Achilles and equine superficial digital flexor tendon (SDFT) are prone to injury, with incidence increasing with aging, peaking in the 5 decade of life in the human Achilles tendon. The interfascicular matrix (IFM), which binds tendon fascicles, plays a key role in energy storing tendon mechanics, and aging alterations to the IFM negatively impact tendon function. While the mechanical role of the IFM in tendon function is well-established, the biological role of IFM-resident cell populations remains to be elucidated. Therefore, the aim of this study was...
Marr N, Hopkinson M, Hibbert AP, Pitsillides AA, Thorpe CT.Three-dimensional imaging modalities for optically dense connective tissues such as tendons are limited and typically have a single imaging methodological endpoint. Here, we have developed a bimodal procedure utilising fluorescence-based confocal microscopy and x-ray micro-computed tomography for the imaging of adult tendons to visualise and analyse extracellular sub-structure and cellular composition in small and large animal species. Results: Using fluorescent immunolabelling and optical clearing, we visualised the expression of the novel cross-species marker of tendon basement membrane, lam...
Garcia T, Hornof WJ, Insana MF.The strong dependence of tendon echogenicity on insonation angle is explored by analyzing echo spectra. Combining echo spectra with high-resolution images from several modalities reveals that fluid spaces surrounding fascicles and bundles are likely sources of ultrasonic scatter. Mathematical models of tendon structure are proposed to explain how the anisotropic microstructure of tendon gives rise to angle-dependent echogenicity. Echo spectra from spontaneously damaged equine tendon samples were compared with normal equine tendon and found to exhibit a dramatic decrease in anisotropic properti...
Wilderjans H, Boussauw B, Madder K, Simon O.Inflammation of the digital flexor tendon sheaths is a chronic and nebulous condition often unresponsive to medical and surgical treatment. Objective: To evaluate the incidence of longitudinal tears (LT) as the underlying cause of chronic tenosynovitis and annular ligament constriction syndrome (ALCS) in warmblood horses. Methods: The records of 25 horses with chronic tenosynovitis and ALCS in which tenoscopical inspection of the digital flexor tendon sheath (DFTS) was performed between 1999-2000 were reviewed. Of 25 horses, 17 were diagnosed with an LT in the deep digital flexor tendon (DDFT)...
Lustgarten M, Redding WR, Labens R, Davis W, Daniel TM, Griffith E, Seiler GS.Compression elastography is an ultrasonographic technique that estimates tissue strain and may have utility in diagnosing and monitoring soft tissue injuries in the equine athlete. Recently, elastography has been proven to be a feasible and repeatable imaging modality for evaluating normal tendons and ligaments of the equine distal forelimb. The purposes of this prospective study were to investigate the ability of elastography to detect spontaneously occurring lesions of equine tendons and ligaments diagnosed with magnetic resonance imaging (MRI) and gray-scale ultrasound (US) and to character...
Donnelly BP, Nixon AJ, Haupt JL, Dahlgren LA.To characterize the nucleotide sequence of equine platelet-derived growth factor (PDGF)-A and -B and analyze temporal expression of these genes in equine tendon after induced tendinitis injury. Animals-18 mature horses. Methods: Genes for equine PDGF-A and -B were reverse transcribed and sequenced from synovial tissue mRNA obtained from a 3-year-old horse. Collagenase-induced lesions were created in the tensile region of the superficial digital flexor tendon in 14 horses; 3 horses served as uninjured control animals. Tendons were harvested and total RNA was isolated from experimental horses 1,...
Hoyt DF, Wickler SJ, Biewener AA, Cogger EA, De La Paz KL.The activity of muscles can be concentric (shortening), eccentric (lengthening) or isometric (constant length). When studying muscle function it is important to know what the muscle fascicles are actually doing because the performance of muscle is strongly influenced by the type of activity: force decreases as a function of shortening velocity during concentric contractions; force produced during eccentric contractions can be stronger than maximum isometric force, and force production is enhanced if a concentric contraction follows an eccentric phase. It is well known that length changes of mu...
Smith RK, Heinegård D.Cartilage oligomeric matrix protein (COMP) is a noncollagenous extracellular matrix protein found predominantly in cartilage, but also in tendon, ligament and meniscus. Studies in man have demonstrated that it may be used as a prognostic marker in rheumatoid arthritis and osteoarthritis. The present study investigated whether tendon injury contributes to serum and tendon sheath synovial fluid levels of COMP in horses. COMP levels, analysed by competitive ELISA, in the digital sheath synovial fluid were more than 10-fold higher than in the serum. Levels were significantly raised when tendon dam...
Busoni V, Heimann M, Trenteseaux J, Snaps F, Dondelinger RF.We describe the abnormal magnetic resonance (MR) imaging findings in the deep digital flexor tendon (DDFT) and distal sesamoid bone in horses with radiographic changes compatible with navicular syndrome. Thirteen postmortem specimens were examined using a 1.5-T magnetic field, with spin echo (SE) T1-weighted, turbo SE (TSE) proton density-weighted (with and without fat saturation), and fat saturation TSE T2-weighted sequences. The limbs were then dissected to compare the MR findings with the gross assessment and histologic examination of the DDFT and distal sesamoid bones. Tendonous abnormalit...
Dudhia J, Becerra P, Valdés MA, Neves F, Hartman NG, Smith RK.Recent advances in the application of bone marrow mesenchymal stem cells (BMMSC) for the treatment of tendon and ligament injuries in the horse suggest improved outcome measures in both experimental and clinical studies. Although the BMMSC are implanted into the tendon lesion in large numbers (usually 10 - 20 million cells), only a relatively small number survive (<10%) although these can persist for up to 5 months after implantation. This appears to be a common observation in other species where BMMSC have been implanted into other tissues and it is important to understand when this loss o...
Gillis C, Pool RR, Meagher DM, Stover SM, Reiser K, Willits N.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...
Berner D, Brehm W, Gerlach K, Gittel C, Offhaus J, Paebst F, Scharner D, Burk J.Treatment of tendon disease with multipotent mesenchymal stromal cells (MSC) is a promising option to improve tissue regeneration. To elucidate the mechanisms by which MSC support regeneration, longitudinal tracking of MSC labelled with superparamagnetic iron oxide (SPIO) by magnetic resonance imaging (MRI) could provide important insight. Nine equine patients suffering from tendon disease were treated with SPIO-labelled or nonlabelled allogeneic umbilical cord-derived MSC by local injection. Labelling of MSC was confirmed by microscopy and MRI. All animals were subjected to clinical, ultrason...
Marr CM, McMillan I, Boyd JS, Wright NG, Murray M.The ultrasonographic and histopathological findings in 12 normal and 28 injured superficial digital flexor tendons, with lesions ranging in duration from 2 days to 15 months, were compared. A consistent relationship between the ultrasonographic and histological findings was demonstrated. The echogenicity of lesions, the distinctness of their delineation from the surrounding tissue, and the presence and arrangement of the linear echoes were useful features by which to assess the ultrasonograms. Acute lesions were anechoic, a complex mixture of anechoic and hypoechoic areas, or diffusely hypoech...
Thorpe CT, McDermott BT, Goodship AE, Clegg PD, Birch HL.Advancing age is a well-known risk factor for tendon disease. Energy-storing tendons [e.g., human Achilles, equine superficial digital flexor tendon (SDFT)] are particularly vulnerable and it is thought that injury occurs following an accumulation of micro-damage in the extracellular matrix (ECM). Several authors suggest that age-related micro-damage accumulates due to a failure of the aging cell population to maintain the ECM or an imbalance between anabolic and catabolic pathways. We hypothesized that ageing results in a decreased ability of tendon cells to synthesize matrix components and m...
Murray SJ, Santangelo KS, Bertone AL.To evaluate early cellular influences of bone morphogenetic protein (BMP)12 and BMP2 on equine superficial digital flexor tenocytes (SDFTNs) and equine bone marrow-derived mesenchymal stem cells (BMDMSCs). Methods: 9 adult clinically normal horses. Methods: BMDMSCs and SDFTNs were cultured in monolayer, either untreated or transduced with adenovirus encoding green fluorescent protein, adenovirus encoding BMP12, or adenovirus encoding BMP2. Cytomorphologic, cytochemical, immunocytochemical, and reverse transcriptase-quantitative PCR (RT-qPCR) analyses were performed on days 3 and 6. Genetic pro...
Pool RR, Meagher DM.Many lesions of the musculoskeletal system of racing horses are either acute traumatic lesions or are chronic biomechanically induced lesions that become suddenly unstable and provoke acute clinical signs. The latter lesions along with those of DJD are much more common and are of much greater overall economic importance to the racing industry than are the acute traumatic injuries. Chronic biomechanical lesions occur at predictable sites and are the result of an imbalance between repetitive microtrauma sustained in athletic performance and adaptive repair mechanisms of skeletal tissues. The dis...
Birch HL, Smith TJ, Poulton C, Peiffer D, Goodship AE.Partial rupture occurs most often to the superficial digital flexor tendon (SDFT) of the forelimb at the mid-metacarpal level. In this study, we tested the hypothesis that the mid-metacarpal region of the SDFT has the smallest cross sectional area (CSA) and a similar collagen content to other regions and, therefore, represents a weak point in the tendon. The SDFT was collected from the forelimbs of 9 horses. Each tendon was marked at 7 different levels from the origin of the accessory ligament to the phalangeal region. The CSA, water content and collagen content was measured at each level. The...
Murphy DJ, Nixon AJ.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...
Kuemmerle JM, Theiss F, Okoniewski MJ, Weber FA, Hemmi S, Mirsaidi A, Richards PJ, Cinelli P.Although several tendon-selective genes exist, they are also expressed in other musculoskeletal tissues. As cell and tissue engineering is reliant on specific molecular markers to discriminate between cell types, tendon-specific genes need to be identified. In order to accomplish this, we have used RNA sequencing (RNA-seq) to compare gene expression between tendon, bone, cartilage and ligament from horses. We identified several tendon-selective gene markers, and established eyes absent homolog 2 () and a G-protein regulated inducer of neurite outgrowth 3 () as specific tendon markers using RT-...
Montgomery L, Elliott SB, Adair HS.To (1) determine the temperature change in equine tendon and muscle during therapeutic ultrasound and (2) develop guidelines for treating horses for muscular or tendinous injury using therapeutic ultrasound. Methods: Experimental, in vivo study. Methods: Adult horses (n = 10). Methods: Thermistors were inserted in the superficial and deep digital flexor tendons (SDFT and DDFT) of the thoracic limbs of 10 adult horses. On the left, 3.3 MHz therapeutic continuous ultrasound was done for 10 minutes at an intensity of 1.0 W/cm(2) and for the right thoracic limb at 1.5 W/cm(2). Thermistors were pla...
Muttini A, Salini V, Valbonetti L, Abate M.The ideal strategy for tendon healing has not been identified to date. Recently, the use of stem cells based therapy has been proposed, due to their ability to proliferate and to differentiate towards specific connective tissues lineages. Embryonic stem cells should be considered the ideal cell source for regenerative therapies, but ethical factors limit their use in humans. Mesenchymal stem cells are more easily available and can be obtained by different sources. Amnion derived stem cells can differentiate towards all three germ layers, and can be used for allogeneic transplantation and store...
Crevier-Denoix N, Ravary-Plumioën B, Evrard D, Pourcelot P.A non-invasive ultrasonic (US) technique of tendon force measurement has been recently developed. It is based on the relationship demonstrated between the speed of sound (SOS) in a tendon and the traction force applied to it. The objectives of the present study were to evaluate the variability of this non-linear relationship among 7 equine superficial digital flexor (SDF) tendons, and the reproducibility of SOS measurements in these tendons over successive loading cycles and tests. Seven SDF tendons were equipped with an US probe (1MHz), secured in contact with the skin overlying the tendon me...
Kersh KD, McClure SR, Van Sickle D, Evans RB.Extracorporeal shock wave therapy (ESWT) is being used to treat desmitis and tendonitis in horses. This paper compares the clinical, ultrasonographic and histological characteristics of ESWT treated collagenase induced superficial digital flexor tendon (SDFT) lesions, versus untreated controls. This blinded study utilizes six mature, healthy horses where bilateral forelimb SDFT lesions were induced. One forelimb was treated while the other served as an untreated control. Three shock wave treatments were administered at three week intervals. At weekly intervals, ultrasonograms were used to meas...
Meershoek LS, van den Bogert AJ, Schamhardt HC.To describe a method to calculate flexor tendon forces on the basis of inverse dynamic analysis and an in vitro model of the equine forelimb and to quantify parameters for the model. Methods: 38 forelimbs of 23 horses that each had an estimated body mass of > or = 500 kg. Methods: Longitudinal limb sections were used to determine the lines of action of the tendons. Additionally, limb and tendon loading experiments were performed to determine mechanical properties of the flexor tendons. Results: The study quantified the parameters for a pulley model to describe the lines of action. Furthermo...
Patterson-Kane JC, Parry DA, Goodship AE, Firth EC.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...
Young M, Moshood O, Zhang J, Sarbacher CA, Mueller POE, Halper J.Horses afflicted with degenerative suspensory ligament desmitis (DSLD) suffer from progressive leg pain and lameness without history of trauma. DSLD is a systemic disorder caused by abnormal accumulation of proteoglycans in many connective tissues. One proteoglycan found in higher quantities in DSLD is decorin. The accumulated decorin has an abnormally glycosylated glycosaminoglycan chain in DSLD. In addition to acellular accumulations of proteoglycans foci of active fibroblasts/tenoblasts were observed in some tendons and suspensory ligaments (SLs) from DSLD cases We have hypothesized that th...
Arensburg L, Wilderjans H, Simon O, Dewulf J, Boussauw B.Longitudinal tears (LTs) of the digital flexor tendons are an important cause of chronic tenosynovitis of the digital flexor tendon sheath (DFTS). The origin of those marginal tears is not yet fully understood. The long-term outcome after medical and surgical treatment is guarded. Objective: To determine the prevalence of LTs of the digital flexor tendons in a large population of horses undergoing diagnostic tenoscopy of the DFTS and to assess the outcome of surgical treatment and the factors influencing the outcome. Methods: Medical records of 130 horses with chronic tenosynovitis of the DFTS...
Johnson SA, Valdés-Martínez A, Turk PJ, Wayne McIlwraith C, Barrett MF, McGilvray KC, Frisbie DD.The range of diagnostic modalities available to evaluate superficial digital flexor tendon (SDFT) injury includes magnetic resonance imaging (MRI), computed tomography (CT) and ultrasonography (US). Direct, comprehensive comparison of multi-modality imaging characteristics to end-point data has not previously been performed using a model of tendinopathy but is required to obtain a better understanding of each modality's diagnostic capabilities. Objective: To compare CT, MRI and US evaluation to outcome measures for histologic, biochemical and biomechanical parameters using an equine surgical m...
Leal Reis I, Lopes B, Sousa P, Sousa AC, Branquinho M, Caseiro AR, Pedrosa SS, Rêma A, Oliveira C, Porto B, Atayde L, Amorim I, Alvites R, Santos JM....Tendon and ligament injuries are frequent in sport horses and humans, and such injuries represent a significant therapeutic challenge. Tissue regeneration and function recovery are the paramount goals of tendon and ligament lesion management. Nowadays, several regenerative treatments are being developed, based on the use of stem cell and stem cell-based therapies. In the present study, the preparation of equine synovial membrane mesenchymal stem cells (eSM-MSCs) is described for clinical use, collection, transport, isolation, differentiation, characterization, and application. These cells are ...
