The musculoskeletal system in horses encompasses the bones, muscles, tendons, ligaments, and joints that facilitate movement and provide structural support. This system is essential for locomotion, athletic performance, and overall health in equine species. The equine skeleton consists of approximately 205 bones, which are connected by joints and supported by a network of muscles and connective tissues. Tendons connect muscles to bones, while ligaments link bones to other bones, contributing to joint stability. The musculoskeletal system is subject to various conditions, including injuries, degenerative diseases, and developmental disorders, which can impact a horse's mobility and performance. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, physiology, pathology, and treatment of musculoskeletal conditions in horses.
Trumble TN.The first month of life is a vulnerable time for foals. They must adjust to their environment while they are still compromised immunologically, and their musculoskeletal system is rapidly growing and adjusting to stresses from an increasing amount of exercise. Therefore, if a foal is born with or acquires an abnormality or disease related to the musculoskeletal system, rapid adjustments must be made to allow the foal to grow and respond so that future athletic performance will not be compromised. Problems must be identified early, which requires thorough examinations. This article summarizes t...
Hoegaerts M, Pille F, De Clercq T, Fulton IC, Saunders JH.A 10-year-old show jumper was evaluated for an acute severe lameness (grade 4 of 5) of the right foreleg. During weight bearing, the toe of the affected limb rotated dorsally suggesting rupture of the deep digital flexor tendon (DDFT). Upon radiographic examination of the hoof, a severe erosion at the flexor surface and a parasagittal fracture of the distal sesamoid bone were found. Ultrasonographic examination confirmed rupture of the DDFT. These findings were confirmed on post-mortem examination. Prior to the acute lameness, the horse was treated with corticosteroid injections into the podot...
Nollet H, Deprez P.Since riders nowadays are expecting the highest level of performance from their horses, muscular disorders therefore represent a major problem for the equine athlete. A lot of research has been done to identify muscular disorders and their etiopathogenesis. Both acquired and inherited forms of muscle diseases have been described. In this review only the latter forms will be mentioned. Major signs of all muscle disorders are muscular stiffness, cramping or pain, muscular fasciculations, muscular atrophy and exercise intolerance. Muscle biopsies can help to identify the cause of rhabdomyolysis o...
Pellegrini-Masini A, Bentz AI, Johns IC, Parsons CS, Beech J, Whitlock RH, Flaminio MJ.Three adult horses were evaluated for signs of musculoskeletal pain, dullness, ataxia, and seizures. A diagnosis of bacterial meningitis was made on the basis of results of CSF analysis. Because primary bacterial meningitis is so rare in adult horses without any history of generalized sepsis or trauma, immune function testing was pursued. Flow cytometric phenotyping of peripheral blood lymphocytes was performed, and proliferation of peripheral blood lymphocytes in response to concanavalin A, phytohemagglutinin, pokeweed mitogen, and lipopolysaccharide was determined. Serum IgA, IgM, and IgG co...
Perkins NR, Reid SW, Morris RS.To investigate risk factors for injury to musculoskeletal structures of the lower fore- and hind-limbs of Thoroughbred horses training and racing in New Zealand. Methods: A case-control study analysed by logistic regression was used to compare explanatory variables for musculoskeletal injuries (MSI) in racehorses. The first dataset, termed the Training dataset, involved 459 first-occurrence cases of lower-limb MSI in horses in training, and the second, the Starting dataset, comprised a subset of those horses that had started in at least one trial or race in the training preparation that ended ...
Perkins NR, Reid SW, Morris RS.To investigate risk factors for injury to the superficial digital flexor tendon (SDFT) and suspensory apparatus (SA) of the forelimbs in Thoroughbred racehorses in New Zealand. Methods: Poisson and negative binomial regression, with exposure time represented by cumulative training days for each horse, were used to relate explanatory variables to the incidence rate (IR) of cases of inflammation of the SDFT (n=51), and injuries involving the SA (n=48) in a population of 1,571 commercially- trained racehorses over 554,745 study days. Only the first occurrence of an injury for any one horse was el...
Södersten F, Ekman S, Eloranta ML, Heinegård D, Dudhia J, Hultenby K.The structure and organisation of the extracellular matrix, and in particular the axial alignment of type I collagen fibrils, are essential for the tensile strength of tendons. The resident tenocytes synthesize and maintain the composition of the extracellular matrix, which changes with age and maturation. Other components of the extracellular matrix include less abundant collagen types II, III, V, VI, XII, proteoglycans and glycoproteins. Cartilage oligomeric matrix protein (COMP) is an abundant non-collagenous pentameric glycoprotein in the tendon, which can bind to collagen types I and II. ...
Bigley RF, Griffin LV, Christensen L, Vandenbosch R.The interfacial strength of secondary osteons from the diaphysis of the Thoroughbred equine third metacarpal was evaluated using the fiber pushout test. The pushout was performed on 300-500 microm sections of 4x4x15 mm bone blocks machined from four anatomic regions of the cortex. Pushout strength was evaluated from proximal to distal location within the diaphysis on four osteon types classified under polarized light on adjacent histologic sections from each block. The shear strength of the interfaces were estimated from shear lag theory. Differences were found in the interfacial strength of o...
Pearce GP, May-Davis S, Greaves D.To investigate the occurrence of geometrical asymmetries in the macro-architecture of left and right femurs from Thoroughbred racehorses previously used in competitive training and racing in New South Wales, Australia. Methods: Detailed postmortem measurements were made of 37 characteristics of left and right femurs from eleven Thoroughbred racehorses euthanased for reasons unrelated to the study. Measurements focused on articulating surfaces and sites of attachment of muscles and ligaments known to be associated with hindlimb locomotion. Results: Five measurements were significantly larger in...
Kapel CM, Webster P, Gamble HR.Only a few studies have compared the muscle distribution of the different Trichinella genotypes. In this study, data were obtained from a series of experimental infections in pigs, wild boars, foxes and horses, with the aim of evaluating the predilection sites of nine well-defined genotypes of Trichinella. Necropsy was performed at 5, 10, 20 and 40 weeks post inoculation. From all host species, corresponding muscles/muscle groups were examined by artificial digestion. In foxes where all Trichinella species established in high numbers, the encapsulating species were found primarily in the tongu...
Swanstrom MD, Zarucco L, Hubbard M, Stover SM, Hawkins DA.Because thoroughbred racehorses have a high incidence of forelimb musculoskeletal injuries, a model was desired to screen potential risk factors for injuries. This paper describes the development of a musculoskeletal model of the thoroughbred forelimb and a dynamic simulation of the motion of the distal segments during the stance phase of high-speed (18 m/s) gallop. The musculoskeletal model is comprised of segment, joint, muscle-tendon, and ligament information. The dynamic simulation incorporates a proximal forward-driving force, a distal ground reaction force model, muscle activations, and ...
Payne RC, Hutchinson JR, Robilliard JJ, Smith NC, Wilson AM.We provide quantitative anatomical data on the muscle-tendon units of the equine pelvic limb. Specifically, we recorded muscle mass, fascicle length, pennation angle, tendon mass and tendon rest length. Physiological cross sectional area was then determined and maximum isometric force estimated. There was proximal-to-distal reduction in muscle volume and fascicle length. Proximal limb tendons were few and, where present, were relatively short. By contrast, distal limb tendons were numerous and long in comparison to mean muscle fascicle length, increasing potential for elastic energy storage. W...
Annandale EJ, Valberg SJ, Essen-Gustavsson B.To determine whether disruption of adenine triphosphate (ATP) regeneration and subsequent adenine nucleotide degradation are potential mechanisms for rhabdomyolysis in horses with polysaccharide storage myopathy (PSSM) performing submaximal exercise. Methods: 7 horses with PSSM and 4 control horses. Methods: Horses with PSSM performed 2-minute intervals of a walk and trot exercise on a treadmill until muscle cramping developed. Control horses exercised similarly for 20 minutes. Serum creatine kinase (CK) activity was measured 4 hours after exercise. Citrate synthase (CS), 3-OH-acylCoA dehydrog...
Caminoto EH, Alves AL, Amorim RL, Thomassian A, Hussni CA, Nicoletti JL.To evaluate the effects of extracorporeal shock wave therapy (ESWT) on affected ligaments in the hind limbs of horses with experimentally induced suspensory ligament desmitis by use of ultrasonographic, ultrastructural, and immunocytochemical techniques. Methods: 10 horses. Methods: Suspensory ligament desmitis was induced in both hind limbs of each horse by use of 2 collagenase injections (administered 2 weeks apart) in each suspensory ligament. Two weeks after the second injection, the right hind limb of each horse was treated with ESWT (3 treatments at 3-week intervals); the left hind limb ...
Davies HM, Watson KM.The aims of this study were to test whether longer third metacarpal (MC3) bones had thicker dorsal cortices in a group of racehorses that were exercising at similar maximum speeds, and to establish if horses with larger differences in length between their right and left MC3 bones showed larger differences in the dorsal cortical thickness between the two limbs. Methods: An observational study. Methods: Forty Thoroughbred racehorses aged between 2 and 6 years and in training at racing speed at two racing stables were used. Two sets of radiographs of each left and right metacarpus of each horse w...
Dabareiner RM, Cohen ND, Carter GK, Nunn S, Moyer W.To determine the types of musculoskeletal problems that result in lameness or poor performance in horses used for team roping and determine whether these problems are different in horses used for heading versus heeling. Methods: Retrospective study. Methods: 118 horses. Methods: Medical records of team roping horses that were evaluated because of lameness or poor performance were reviewed to obtain information regarding signalment, primary use (ie, head horse or heel horse), history, results of physical and lameness examinations, diagnostic tests performed, final diagnosis, and treatment. Resu...
Da Costa Gómez TM, Barrett JG, Sample SJ, Radtke CL, Kalscheur VL, Lu Y, Markel MD, Santschi EM, Scollay MC, Muir P.Functional adaptation of bone normally protects the skeleton from fracture during daily activity. Accumulation of microcracking and loss of osteocytes have been implicated in the regulation and initiation of targeted (reparative) remodeling of bone and, in certain situations, the development of fatigue or stress fracture. We performed a histologic study of the dorsal cortex of the mid-diaphysis of the third metacarpal (Mc-III) bone of Thoroughbred racehorses after bones were bulk-stained in basic fuchsin and transverse calcified sections were prepared. The Thoroughbred racehorse is an extreme ...
Taylor DD, Hood DM, Potter GD, Hogan HA, Honnas CM.To evaluate patterns of digital cushion (DC) displacement that occur in response to vertical loading of the distal portion of the forelimb in horses. Sample Population-Forelimbs from 10 horses with normal feet. Methods: Patterns of DC displacement induced by in vitro vertical limb loading were determined. Load-induced displacement of the DC was defined as the magnitude and direction of displacement of 6 radio-dense, percutaneously implanted markers in specific regions of the DC. The effects of solar support and nonsupport on displacement of the DC were compared. Results: Regional displacement ...
Edwards LJ, Goodship AE, Birch HL, Patterson-Kane JC.To determine whether specific treadmill exercise regimens would accelerate age-related changes in collagen fibril diameter distributions in the common digital extensor tendon (CDET) of the forelimbs of young Thoroughbreds. Methods: 24 female Thoroughbreds. Methods: Horses were trained for 18 weeks (6 horses; short term) or 18 months (5 horses; long term) on a high-speed treadmill; 2 age-matched control groups (6 horses/group) performed walking exercise only. Horses were (mean +/- SD) 24 +/- 1 months and 39 +/- 1 months old at termination of the short-term and long-term regimens, respectively. ...
Martínez AC, Prieto D, Hernández M, Rivera L, Recio P, García-Sacristán A, Benedito S.This study evaluates the mechanisms underlying endothelium-dependent responses to acetylcholine in horse deep dorsal penile veins. Acetylcholine-induced relaxation was abolished by endothelium removal, the soluble guanylyl cyclase-inhibitor, and the nitric oxide (NO) synthase inhibitors. Acetylcholine-induced relaxation was inhibited by high K+ concentrations and blockade of large-conductance Ca(2+)-activated potassium (BK(Ca)) channels, and voltage-dependent potassium (K(v)) channels. Relaxations were unaffected by a small-conductance K(Ca) (SK(Ca)) channel blocker, or an ATP-sensitive potass...
van der Harst MR, van de Lest CH, Degroot J, Kiers GH, Brama PA, van Weeren PR.A detailed and comprehensive insight into the normal maturation process of the different tissues that make up functional units of the locomotor system such as joints is necessary to understand the influence of early training on musculoskeletal tissues. Objective: To study simultaneously the maturation process in the entire composite structure that makes up the bearing surface of a joint (cartilage, subchondral and trabecular bone) in terms of biochemical changes in the tissues of juvenile horses at 2 differently loaded sites of the metacarpophalangeal joint, compared to a group of mature horse...
Tessier C, Holcombe SJ, Stick JA, Derksen FJ, Boruta D.There is a need to understand the process which leads to failure of recruitment of the stylopharyngeus muscle in clinical cases of nasopharygeal collapse. We therefore studied the timing and intensity of stylopharyngeus muscle activity during exercise in horses. Objective: To measure the electromyographic (EMG) activity of the stylopharyngeus muscle in exercising horses and correlate it with the breathing pattern. Methods: Five horses were equipped with a bipolar fine wire electrode placed on the stylopharyngeus muscle and a pharyngeal catheter. The horses exercised on a treadmill at speeds co...
Pearson EG, Snyder SP, Saulez MN.The medical records of eight horses with histological evidence of myodegeneration of the masseter muscles were examined. While they were alive their most common clinical signs had included difficulty in eating or opening their mouths, weight loss, difficulty in moving, and noticeable atrophy of the masseter muscles. The serum activities of muscle enzymes were abnormally high in all of the horses. Whole blood and/or liver selenium and vitamin E concentrations were less than the reference ranges in some of the horses. The lesions varied with the stage of the disease and consisted of swelling and...
Murray RC, Dyson SJ, Weekes JS, Short C, Branch MV.Distal tarsal pain is a common reason for hind limb lameness, but diagnosis cannot always be made on radiographic examination. Scintigraphy may allow detection of subtle changes undetected by other diagnostic methods. We hypothesized that (1) distal tarsal pain would be associated with a loss of the expected pattern of radiopharmaceutical uptake (RU) detected in normal horses, (2) distal tarsal RU would be greater in limbs with tarsal pain than without pain, (3) RU in painful tarsi with radiographic evidence of osteoarthritis (OA) would be greater than in distal tarsal pain with no radiographi...
Read EK, Chandler D, Wilson DG.To compare the biomechanical characteristics and mode of failure of 2 techniques using parallel 5.5 mm screws for pastern joint arthrodesis in horses. Methods: Randomized block design, for horse (1-5), method of fixation (two 5.5 mm screws versus three 5.5 mm screws), side (right, left), and end (front, hind). Constructs were tested to failure in 3-point bending. Methods: Twenty limbs (5 cadavers). Methods: A combined aiming device was used to facilitate screw placement. Two parallel 5.5 mm screws were inserted in lag fashion in 1 limb of a pair, and three 5.5 mm screws were inserted in the co...
Kristoffersen M, Ohberg L, Johnston C, Alfredson H.Recent research on chronic painful Achilles tendons in humans using ultrasonography and immunohistochemistry, has demonstrated an association between neurovascular ingrowth and tendon pain. In horses, chronic debilitating tendon conditions are well-known to be very difficult to treat, and the background to impaired function and pain is not scientifically clarified. In a collaborative research project between the Sports Medicine Unit in Umeå and Strömsholm Equine Hospital, grey-scale ultrasonography (US) and colour Doppler (CD) examination were performed in ten horses with chronic tendon inju...
Kim JS, Hinchcliff KW, Yamaguchi M, Beard LA, Markert CD, Devor ST.The purpose of the present study was to determine the age-related changes in myosin heavy chain (MHC) composition and muscle oxidative and glycolytic capacity in 18 horses ranging in age from two to 30 years. Muscle samples were collected by excisional biopsy of the semimebranosus muscle. MHC expression and the key enzymatic activities were measured. There was no significant correlation between horse age and the proportions of type-IIA and type-IIX MHC isoforms. The percentage of type-I MHC isoforms decreased with advancing age. Muscle citrate synthase activity decreased, whereas lactate dehyd...
Mills PC, Hills Y, Hills BA.To investigate the presence of surface-active phospholipid (SAPL, or surfactant) in equine tendon and tendon sheath fluid. Methods: The left front flexor tendon and sheath were removed from five Thoroughbred horses. Phospholipid was extracted from tendon sheath fluid using Folch reagent and quantified using spectroscopy. Transmission electron microscopy (TEM) was used to observe the tendon surfaces. Results: The presence of phospholipid (90.6 (SD 4.3) microg/ml) in tendon sheath fluid, plus the appearance of oligolamellar layers and lamellar bodies on the tendon surface were indicative of SAPL...
Ortved KF.Osteochondrosis is common in young, athletic horses. Some lesions respond to conservative therapy. Surgical management is the mainstay of treatment. Arthroscopic debridement is useful in the femoropatellar joint, tarsocrural joint, fetlock joint, and shoulder joint. Debridement is associated with good outcomes, except in the shoulder joint. Osteochondrosis lesions in the elbow may be difficult to access arthroscopically, thereby transosseous debridement. Surgical management of subchondral cystic lesions of the medial femoral condyle consists of debridement, debridement with grafting, transcond...
Aim of this study was to document the normal computed tomographic tenography findings of digital flexor tendon sheath. Six ex vivo normal equine forelimbs were used. An axial approach was used to inject 185 mg/mL of iopamidol in a total volume of 60 mL into the digital flexor tendon sheaths. Single-slice helical scans, with 5 mm thickness, spaced every 3 mm, for a pitch of 0.6, and with bone algorithm reconstruction, were performed before and after injections of contrast medium. To obtain better image quality for multiplanar reconstruction and 3D reformatting, postprocessing retrorecon...
Lindner A, Dag S, Marti-Korff S, Quiroz-Rothe E, López Rivero JL, Drommer W.The collection of muscle samples in horses to estimate their performance potential, adaptations to training and diagnosis of exertional myopathies is of increasing interest. This study was designed to examine whether repeated biopsying of the gluteus medius muscle at 7 week intervals alters morphology and muscle fibre variables in the sampling area. The gluteus had been biopsied 3 times previously, each biopsy separated by a 7 week interval. Seven weeks after the last biopsy, this study was initiated. Percutaneous needle biopsies were taken from left and right muscles at 2 depths (2 and 6 cm) ...
Firth EC, Greydanus Y.The talus and proximal and distal epiphysis of the humerus, radius, femur, tibia and distal metacarpus of 20 foals aged 0 to 150 days were obtained at necropsy and sawn sagittally into slabs 4 to 8 mm thick. The thickness of the cartilage (articular cartilage and unossified epiphyseal cartilage) was measured in three to five places in each slab, using a sliding calliper. In most epiphyses, the site, or sites, of thickest cartilage was constant in all foals examined. The difference between thickest and thinnest cartilage within one epiphysis was greatest in distal femora and least in distal met...
Bowling AT, Byrns G, Spier S.The pedigree origin of a base pair substitution in the horse muscle sodium channel gene that confers susceptibility to the muscle disease hyperkalemic periodic paralysis (HYPP) was investigated with a set of 978 Quarter Horses. The horses were chosen at random, based on a collection of blood samples taken between 1989 and 1991 to meet parentage testing requirements, primarily but not exclusively from breeding stallions. The frequency of Quarter Horses positive for the base pair substitution, all heterozygotes, was 4.4%, which corresponds to an allelic frequency of 0.02. All horses positive for...
Jenner F, Ross MW, Martin BB, Richardson DW.To review the outcome of equine shoulder osteochondrosis (OC) with surgical or conservative treatment. Methods: Retrospective study of 32 horses, less than two years of age, with scapulohumeral joint (SHJ) OC. The lesion severity was graded based on measurements taken from lateromedial radiographs. Follow-up information was obtained from racing records or telephone conversations with owners. Successful outcome was defined as the ability of the horse to perform its intended use. Results: Sixteen of 32 horses were affected bilaterally (48 joints). Eleven of 16 horses with bilateral OC underwent ...
Geelen SN, Sloet van Oldruitenborgh-Oosterbaan MM, Beynen AC.Feeding of a fat-rich diet to horses may enhance the flux of fatty acids, in the form of triacylglycerols (TAG), through the circulation into skeletal muscle. This hypothesis was tested indirectly by measuring the concentration of plasma TAG and the activity of lipoprotein lipase (LPL) in post heparin plasma. Six mature horses were fed a high-fat or a control diet according to a crossover design with feeding periods of 6 weeks. The control diet contained 1.5% fat in the dry matter and the high-fat diet 11.8%. The high-fat diet was formulated by adding soybean oil to the control diet at the exp...
Thurmon JC.The peculiarities of the equine species present a number of unique situations that must be addressed when horses are anesthetized. Perhaps the most troublesome situation is related to the horse's size. Though the horse's large lungs are responsible in part for its sustainable athletic ability, they are detrimental to effective ventilation when the horse is anesthetized and placed in a recumbent position. Of major concern is depression of ventilation and cardiovascular function. Hypercapnia and hypoxemia usually result from hypoventilation, and with time all anesthetized horses suffer from some...
Kannegieter NJ, Burbidge HM.The radiographic and arthroscopic findings in 150 carpal joints in 114 lame horses were compared. Chip, slab, or sagittal fractures were identified in 130 (87%) joints. In 101 (78%) of these there was good agreement between radiographic and arthroscopic findings on the number and position of fractures. In 23 (18%) joints, chip fractures additional to those seen radiographically were found arthroscopically. In one joint a large chip fracture from the craniolateral aspect of the distal radius was identified only by arthroscopy, while in 6 joints fractures were identified only by radiography. Obs...
Boero MJ, Kneller SK, Baker GJ, Metcalf MR, Twardock AR.Injury of the lateral collateral ligaments of the tarsocrural joints was diagnosed in nine Standardbred pacers. The average age was 4.9 years. The severity of the lameness varied from severe to subtle and joint effusion was seen in eight of 10 tarsocrural joints. A positive hindlimb flexion test was seen in four of six cases in which results were recorded. The identification of the site of involvement was based on a focal intense 'hot spot' seen on scintigraphy, and new bone formation seen radiographically at the anatomical sites of insertion of the long lateral collateral ligament of the tars...
Wentink GH.The locomotor pattern of the hind limb of seven horses has been studied in intact animals and after transection of the following structures: the peroneus tertius tendon, the cranial tibial muscle, both cranial tibial muscle and peroneus tertius tendon, and the superficial digital flexor tendon. The investigation was carried out by high speed cinematography and electromyography. It is concluded that (1) the muscles and tendons over the cranial aspect of the tibia play an important role during the support phase; (2) the movements of the hind limb may be performed without the action of the crania...
Gibson KT, Burbidge HM, Anderson BH.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...
Foland JW, Trotter GW, Stashak TS, McIlwraith CW, Turner AS, Aanes WA.Fifty-five horses were presented to Colorado State University Veterinary Teaching Hospital between 1st of January 1980 and 31st of December 1989 for treatment of distal limb lacerations involving flexor tendons (n = 35) or extensor tendons (n = 20). Of the 35 flexor tendon lacerations, 11 horses were killed without treatment and 24 horses were treated. Twenty-two horses were included in determining outcome. Four (18 per cent) returned to their original level of use, nine (41 per cent) returned to limited riding, seven (32 per cent) returned to breeding or pasture soundness and two (9 per cent)...
Batson EL, Reilly GC, Currey JD, Balderson DS.The metacarpal of the horse is severely loaded during vigorous exercise. Metacarpal specimens have a greater impact strength in young horses that have been exercised than in those that have only been walked. We did not find a corresponding difference in the radius of the same horses. We show that cranial (anterior) cortical bone from the radius, which is loaded in tension during locomotion, has a greater Young's modulus, and tensile and bending strength, than bone from the caudal (posterior) cortex, which is loaded in compression. Caudal bone is, however, stronger in compression. The differenc...
Naylor RJ, Piercy RJ.To produce a clonal equine myoblast cell line that retains the ability to divide for multiple passages and differentiate into multinucleated myotubes during specific conditions. Methods: Cultured primary equine skeletal muscle-derived cells from a healthy Thoroughbred. Methods: Cell cultures were transfected by electroporation with a plasmid (pNIT) that expresses the temperature-sensitive simian vacuolating virus 40 large T antigen (TAg), which can be controlled by a doxycycline-responsive promoter. Cells that stably integrated the TAg were selected and expanded to passage 25. For each passage...
Smyth PA, Rifkin RE, Jackson RL, Reid Hanson R.The naturally occurring structure of articular cartilage has proven to be an effective means for the facilitation of motion and load support in equine and other animal joints. Cartilage has been found to be a complex and dynamic medium, which has led to an incomplete understanding of the nature and operating mechanisms acting within a joint. Although cartilage has biphasic and triphasic properties, it is believed that the performance of equine articular joints is influenced by the surface roughness of the joint cartilage (Ateshian et al., '98; Chan et al., 2011; Yao and Unsworth, '93). Various...
Martin-Flores M.This article briefly reviews the physiology of the neuromuscular junction and the pharmacologic mechanisms of neuromuscular blocking agents. The clinical use of modern agents is discussed. Monitoring techniques used to assess the level of neuromuscular block and to exclude residual paralysis at the end of an anesthetic procedure are reviewed.
Wagner FC, Reese S, Gerlach K, Böttcher P, Mülling CKW.Long-term cyclic tensile testing with equine palmar/plantar tendons have not yet been performed due to problems in fixing equine tendons securely and loading them cyclically. It is well established that the biomechanical response of tendons varies during cyclic loading over time. The aim of this study was to develop a clamping device that enables repetitive cyclic tensile testing of equine superficial digital flexor tendon for at least 60 loading cycles and for 5 min. Results: A novel cryo-clamp was developed and built. Healthy and collagenase-treated pony SDFTs were mounted in the custom-ma...
Watts AE.Mesenchymal stem cells (MSCs) are used as a regenerative therapy in horses for musculoskeletal injury since the late 1990s and in some regions are standard of care for certain injuries. Yet, there is no Food and Drug Administration-approved MSC therapeutic in the United States for horses. In humans, lack of regulatory approval in the United States has been caused by failure of late-phase clinical trials to demonstrate consistent efficacy, perhaps because of nonuniformity of MSC preparation and application techniques. This article discusses clinical evidence for musculoskeletal applications of ...
Yu CH, Kim UR, Kwon TK.In this study, we assessed indoor horse riding exercise's effects on basal physical exercise and activities of daily living (ADL) function using horse riding equipment, involving elderly test subjects (in their sixties). The participants were 20 people with no impediment to activity. They participated in experiments that lasted 60 min per day, 3 days per week, over 8 weeks, using the "SRider" (Rider Co. and Chonbuk National University Korea).We measured trunk flexion, sit-up, whole-body reaction, leg strength, and maximal oxygen uptake as basal physical fitness parameters. Also, 3-m gait, sing...
Mucher E, Jayr L, Rossignol F, Amiot F, Gidrol X, Barrey E.Progress could be achieved by using microarrays to understand metabolic adaptations and disorders in equine muscle in response to exercise. Objective: To test the feasibility of using mouse cDNA microarrays to analyse gene expression profile in normal equine muscles. Methods: Muscular biopsies of dorsal gluteus medius and longissimus lumborum were done in 4 healthy Standardbreds. Total RNA was extracted from the muscle samples. The concentration and quality of RNA were measured before and after amplification. Gene expression profiles were measured using mouse cDNA microarrays including 15,264 ...
Symons JE, Entwistle RC, Arens AM, Garcia TC, Christiansen BA, Fyhrie DP, Stover SM.To determine morphological and mechanical properties of trabecular bone of horses with a bone fragility syndrome (BFS; including silicate-associated osteoporosis). Methods: Cylindrical trabecular bone samples from the distal aspects of cadaveric third metacarpal bones of 39 horses (19 horses with a BFS [BFS bone samples] and 20 horses without a BFS [control bone samples]). Methods: Bone samples were imaged via micro-CT for determination of bone volume fraction; apparent and mean mineralized bone densities; and trabecular number, thickness, and separation. Bone samples were compressed to failur...
Maldonado MD, Parkinson SD, Story MR, Haussler KK.Chiropractic care is a common treatment modality used in equine practice to manage back pain and stiffness but has limited evidence for treating lameness. The objective of this blinded, controlled clinical trial was to evaluate the effect of chiropractic treatment on chronic lameness and concurrent axial skeleton pain and dysfunction. Two groups of horses with multiple limb lameness (polo) or isolated hind limb lameness (Quarter Horses) were enrolled. Outcome measures included subjective and objective measures of lameness, spinal pain and stiffness, epaxial muscle hypertonicity, and mechanical...
McCormick JD, Watkins JP.Double plate fixation has been reported in a small number of horses with comminuted fractures of the middle phalanx. There are no published reports using this technique in the management of other injuries that destabilise the proximal interphalangeal joint (PIJ), including biaxial palmar/plantar eminence fractures and disruption of the palmar/plantar soft tissue support structures of the PIJ. Furthermore, there is a paucity of information on the long-term prognosis for horses undergoing double plate fixation to manage destabilising injuries of the PIJ. Objective: To document further the clinic...
Clothier J, Hinch G, Brown W, Small A.Clear definitions of 'normal' equine gestation length (GL) are elusive, with GL being subject to a considerable number of internal and external variables that have confounded interpretation and estimation of GL for over 50 years. Consequently, the mean GL of 340 days first established by Rossdale in 1967 for Thoroughbred horses in northern Europe continues to be the benchmark value referenced by veterinarians, breeders and researchers worldwide. Application of a 95% confidence limit to reported GL range values indicates a possible connection between geographic location and GL. Improved kno...
Easley KJ, Stashak TS, Smith FW, Van Slyke G.Thirty-six superficial digital flexor tendons from nine fresh equine cadavers were transected and sutured with size 2 monofilament nylon. Nine tendons were repaired with each of four suture patterns: single-locking loop, double-locking loop, triple-locking loop, or three-loop pulley. The times required for application, tensile strengths, resistance to distraction (gap), and modes of failure were analyzed. The mean times required were: single-locking loop, 3 mins, 15 secs; double-locking loop, 4 mins, 15 secs; triple-locking loop, 10 mins, 50 secs; and three-loop pulley, 4 mins. The double-lock...
Tomlinson JE, Redding WR, Sage A.Ultrasonographic examination of the tarsus was performed on four clinically and radiographically normal limbs of adult horses. Particular attention was paid to the articular cartilage surfaces of the trochlear ridges of the talus and the distal intermediate ridge of the tibia. Two separate measurements of articular cartilage thickness were acquired from a longitudinal view at each site. Anatomy was confirmed with post mortem dissection. Ultrasonography was found to be a practical method for imaging the articular cartilage over the trochlear ridges of the talus and distal intermediate ridge of ...
Inoue Y, Matsui A, Asai Y, Aoki F, Yoshimoto K, Matsui T, Yano H.We studied the response of biochemical markers of bone metabolism to exercise intensity in horses. Four horses were walked on a mechanical walker for one week (pre-exercise). Then they performed low-speed exercise on a high-speed treadmill in the first week and medium-speed exercise in the second week and high-speed exercise in the third week of training. We measured two indices of bone resorption, serum hydroxyproline concentration and the urinary deoxypyridinoline/creatinine ratio, and serum osteocalcin (OC) concentration as an index of bone formation. Both indices of bone resorption gradual...
Lopez-Navarro G, Trigo-Tavera FJ, Rodriguez-Monterde A, Gutierrez-Ospina G, Arechavaleta-Velasco M, Schumacher J, Schumacher J.Proximal suspensory desmitis (PSD) is a common cause of lameness in the pelvic limb, but could also affect the thoracic limb of competing and non-competing horses. Most horses diagnosed with PSD in a thoracic limb respond to rest followed by controlled exercise, but in a small percentage of affected horses, lameness persists. In one study, four horses chronically lame because of PSD in a thoracic limb became sound after neurectomy of the deep branch of the lateral palmar nerve (DBLPaN), which innervates the proximal aspect of the suspensory ligament (SL; Guasco et al., 2013). Whether neurectom...
Gibson KT, Burbidge HM, Pfeiffer DU.This study documents the results of non-surgical treatment and treatment by superior check desmotomy in Thoroughbred racehorses with superficial digital flexor (SDF) tendonitis. Methods: A prospective study was made of 124 thoroughbred racehorses with unilateral or bilateral SDF tendonitis. Methods: The flexor tendons were assessed by physical and ultrasonographic examination before treatment, and the lesions detected in affected tendons were characterised according to lesion type, length and cross-sectional area. Ninety three horses were managed non-surgically and 31 by superior check desmoto...
