Joint health in horses involves the study of anatomical structures such as cartilage, synovial fluid, ligaments, and bones that contribute to the function and mobility of equine joints. Research in this area focuses on understanding the physiology of equine joints, the mechanisms of joint disorders, and the effects of wear and tear over time. Common joint issues in horses include osteoarthritis, synovitis, and joint effusion, which can impact performance and quality of life. Diagnostic techniques often involve imaging, synovial fluid analysis, and clinical evaluation to assess joint condition. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, pathology, diagnostics, and therapeutic approaches related to joint health in horses.
Degenerative joint disease is one of the main causes of equine early retirement from pleasure riding or a performance career. The disease is initially triggered by an abnormal loading of normal cartilage or a normal loading of abnormal cartilage. This primary insult is accompanied with joint inflammation, which leads to further progressive degeneration of the articular cartilage and changes in the surrounding tissues. Therefore, in search for an effective treatment, 75 adult horses with early signs of degenerative fetlock joint disease were enrolled in a randomized, multicenter, double-blinded...
In horses, osteoarthritis (OA) mostly affects metacarpophalangeal and metatarsophalangeal (fetlock) joints. The current modalities used for diagnosis of equine limb disorders lack ability to detect early OA. Here, we propose a new alternative approach to assess experimental cartilage damage in fetlock joint using Acoustic Emissions (AE). Objective: To evaluate the potential of AE technique in diagnosing OA and see how AE signals changes with increasing severity of OA. Methods: An in vitro experimental study. Methods: A total of 16 distal limbs (8 forelimbs and 8 hindlimbs) from six Finn horses...
Friedlund AM, Bracamonte JL, Koziy RV, Epp T, Thomas KL.To evaluate if high-volume lavage results in a negative bacterial culture of egress fluid, regardless of pathogen in an experimental model of equine septic arthritis. Methods: Experimental study. Methods: A total of 11 horses in three groups (lipopolysaccharide [LPS] Group 1, n = 4; Escherichia coli [E. coli] Group 2, n = 4; Staphylococcus aureus [S. aureus] Group 3, n = 3). Methods: A middle carpal joint of each horse was injected with LPS (synovitis Group 1), E. coli (septic arthritis Group 2) or S. aureus (septic arthritis Group 3). Arthroscopic lavage of the middle carpal joint...
McCoy AM, Lopp-Schurter CT, Bishop RC, Narotsky A, Grogger K, Kemper AM.To determine the natural progression of tarsal osteochondrosis (OC) in a cohort of Standardbred foals and assess the impact of gait preference (trotting vs. pacing). Methods: Longitudinal observational cohort study. Methods: Client-owned Standardbred foals (n = 148). Methods: Tarsal radiographs were taken every 2 months from 2 to 12 months of age and foals were video monitored to document time spent pacing or trotting. Differences between groups were assessed using χ analysis. Survival analysis was used to determine if lesion healing differed between groups over time. Results: Of 148 ...
Qiu Z, Wang J, Zhang Y, Liu X, Wei C, Ma T.Musculoskeletal injuries represent a primary cause of suboptimal performance and early retirement in equine athletes. To address this challenge, the veterinary community has long endeavored to develop safer and more effective therapeutic strategies. Extracorporeal shock wave therapy (ESWT), as a treatment for equine musculoskeletal injuries, has garnered substantial attention among equine veterinarians. Focused on the theme ESWT Therapy for Equine Musculoskeletal Disorders: From biological mechanisms to clinical applications, this article systematically reviews existing literature on the biolo...
Beggan CP, Panizzi L, Oliver LJ.To measure microsphere recovery following needle-through-and-through lavage (NTAT) of the metacarpo-/metatarsophalangeal joint (fetlock) and digital flexor tendon sheath (DFTS) compared to endoscopic lavage (EL). Methods: Ex vivo experimental study. Methods: Adult equine cadavers immediately following euthanasia (n = 10). Methods: Colored 15 μm microspheres (2 million) were injected into fetlock joints and DFTS. Synovial structures were assigned to NTAT or EL groups. Each lavage was performed using 5 L of 0.9% NaCl, sequentially collecting egress fluid for microsphere quantification. Re...
Woods T, Dixon J, Melvaine C, Fraser B.To determine the ideal location of a medial tenoscopic portal in the equine carpal flexor tendon sheath (CFTS) using contrast computed tomography (CT). Methods: Experimental cadaver study. Methods: A total of 20 entire forelimbs from adult Standardbred horses. Methods: Contrast media diluted in saline was injected into the CFTS from a lateral approach before manually flexing and extending the limb 20 times to disperse the contrast solution. The limbs were placed in lateral recumbency and a capped 21-gauge 1.5 inch needle was placed approximately 5 mm proximal and 32 mm caudal to the palpab...
Wallace PD, Schoonover MJ, Williams MR, Maxwell LK, Taylor JD.To evaluate plasma and synovial fluid amikacin concentrations following cephalic or saphenous IV regional limb perfusion (IVRLP) with a dosing protocol of 25 mg of amikacin/kg, divided into 16.7 mg/kg systemically and 8.3 mg/kg regionally. We hypothesized that plasma amikacin concentrations observed at 30 minutes after systemic administration would exceed a therapeutic target of 53 μg/mL and that synovial fluid concentrations would exceed a therapeutic target of 80 μg/mL. Unassigned: Over a 5-month period (spring/summer of 2023), 8 healthy neonatal foals were administered each protocol at le...
Peralta AG, Raeisimakiani P, Hayashi K, Mahal LK, Reesink HL.Post-traumatic osteoarthritis (PTOA) is a common sequela to joint injury in both humans and companion animal species such as horses and dogs. Despite the increasing prevalence of osteoarthritis (OA) in humans, investigation of glycosylation changes associated with OA remains in its infancy. Recent advances, such as lectin microarray analysis, now enable detailed glycan profiling in complex biofluids such as synovial fluid. Using lectin microarray technology, this study characterized glycosylation patterns in synovial fluid samples from healthy and OA-affected joints in horses, dogs, and humans...
Vishwanath K, McClure SR, Bonassar LJ.Intra-articular injections of hyaluronic acid (HA) are the cornerstone of osteoarthritis (OA) treatments. However, the mechanism of action and efficacy of HA viscosupplementation are debated. As such, there has been recent interest in developing synthetic viscosupplements. Recently, a synthetic 4 wt% polyacrylamide (pAAm) hydrogel was shown to effectively lubricate and bind to the surface of cartilage in vitro. However, its ability to localize to cartilage and alter the tribological properties of the tissue in a live articulating large animal joint is not known. The goal of this study was to...
Harbowy RM, Nielsen BD, Colbath AC, Robison CI, Buskirk DD, Logan AA.Though circular exercise is commonly used in equestrian disciplines, it may be at the detriment of horses' musculoskeletal system. To investigate the effects of circular exercise on bone and joint health, 42 lambs were randomly assigned to a non-exercised control, straight-line, small circle, or large circle exercise regime at a slow (1.3 m/s) or fast (2.0 m/s) speed for 12 wk. Blood samples were taken biweekly. Animals were humanely euthanized upon study completion, and the fused third and fourth metacarpals were collected for biomechanical testing and bone density analysis. Fast groups were ...
Loder RT, Walker AL, Blakemore LC.Horse riding is a common sport, but no study specifically addresses joint dislocations. The purpose of this study is to describe joint dislocations due to equines using a national emergency department (ED) database. Such data can be helpful in injury prevention strategies. Unassigned: The National Electronic Injury Surveillance System (NEISS) database for the years 2000-2023 was used. The NEISS database is a statistically representative sample of injuries seen in EDs across the US giving national estimates. Mechanism of injury was tabulated into groups: 1) did the patient fall from the horse 2...
Cameron-Whytock H, Divall H, Lewis M, Apps C.The study hypothesised that a markerless motion capture system can provide kinematic data comparable to a traditional marker-based system for riders mounted on a horse. The objective was to assess the markerless system's accuracy by directly comparing joint and segment angle measurements taken during walking and trotting with those obtained from a marker-based system. Ten healthy adult participants performed five dynamic trials during walking and trotting. A twelve-camera marker-based system and eight-camera 2D video-based system were synchronised. Three-dimensional hip, knee, shoulder and elb...
Semevolos SA, Marchant EA.The marginal transitional zone (MTZ) is peripherally located within the diarthrodial joint, and represents the junction of synovium, fibrous joint capsule, articular cartilage, periosteum, and bone. The purpose of this study is to characterize age-related differences in protein expression of matrix and molecular regulators in the marginal transitional zone of neonatal and weanling foals. Several families of proteins with known roles in cartilage and bone development are investigated, including matrix molecules, members of the Wnt signaling family, apoptotic factors and paracrine cell signaling...
Ursini T, Villagomez A, Dooley M, George LS, Levine D.To describe and demonstrate subjective and objective techniques for assessing the quality and passive range of motion (ROM) of the distal forelimb and hind limb joints of the horse. Special attention will be given to the tarsus, carpus, and fetlock joints, as these sites are most prone to injury and/or pathology and thus most clinically relevant. Unassigned: Adult horses undergoing distal limb joint ROM assessment for clinical diagnostic or treatment monitoring purposes. Unassigned: First, subjective techniques for assessing distal limb joint motion and end-feel as well as general guidelines f...
Patterson HE, Yocom AF, Seabaugh KA, Kawcak CE, Contino EK.Recent evidence has shown that perineural analgesia may be less specific than previously thought. Objective: To compare the effects of four distal limb perineural analgesia techniques on resolving synovitis-induced lameness of the equine metacarpophalangeal joint (MCPJ). Methods: Nine horses had one MCPJ injected with 75ng of recombinant equine interleukin-1β (reIL-1β). Ten hours later, horses underwent one of two blocking patterns: (1) a palmar digital (PDNB) followed by an abaxial sesamoidean (ASNB) nerve block or (2) a palmar metacarpal (PMNB) followed by a palmar (PaNB) nerve block. Skin...
Miller GP, Cornille JL, Hanning R, Lee AKK, Uhl EW, Osborn ML.Lameness is often associated with degenerative joint disease (DJD). Current therapies focus on minimizing pain or treating specific lesions but generally do not address the pathomechanical forces that are the root cause of degeneration. Treatments based on specific, whole-body therapies are becoming common in humans with DJD, but are still not routinely applied in equine cases. Designing targeted therapies for horses requires recognizing habitual postures and movements that are pathological. An important but often missing component for understanding movement postures is accurate and manipulata...
Jasiński T, Borowska M, Juszczuk-Kubiak E, Turek B, Kaczorowski M, Bąk M, Żuk J, Domino M.Horses presenting with temporomandibular joint (TMJ) dysfunctions are often clinically evaluated for TMJ osteoarthritis (OA). Due to the unique characteristic of TMJ-related pain, the clinical diagnosis of equine TMJ OA is challenging; however, it may be supported by computer-aided tools incorporating biomarker data. This study aims to evaluate a machine learning-based approach to address a binary classification distinguishing healthy TMJs from TMJ OA. Among 50 equine cadaver heads, 82 TMJs were included and annotated as healthy or OA based on histological and computed tomography (CT) findings...
Brown NL, Irandoust S, Thom EJ, Whitton RC, Henak CR, Muir P.Condylar stress fracture of the third metacarpal bone (MC3) is a common catastrophic injury in Thoroughbred racehorses and is associated with parasagittal groove (PSG) subchondral osteolysis. Standing computed tomography (sCT) imaging enables sensitive identification of this fatigue-induced early subchondral bone injury (SBI), but there is no objective method for identifying racehorses at heightened risk of condylar stress fracture. Objective: To estimate PSG first principal strain in elite Thoroughbred racehorses that have undergone subjective risk assessment using sCT fetlock screening. Meth...
Benetti E, Tambella AM, Andreis SN, Witte S, Di Bella C, Spadavecchia C.Osteoarthritis (OA) is a prevalent cause of chronic pain and lameness in horses. Whereas lameness can be quantified using objective measures, the assessment of OA-associated pain remains challenging. This study aimed to evaluate the applicability of the Client-Specific Outcome Measure (CSOM), a tool widely used in small animals, for the assessment of chronic OA pain in horses through caretaker evaluation. Unassigned: Seventeen privately owned horses with confirmed OA were enrolled in a 20-week randomized, double-blind, placebo-controlled study. For each horse, three individual pain-related ind...
Lani NR, Schoonover MJ, Williams MR, Messina A, Rudra P.To establish whether tourniquet type and number influence synovial fluid amikacin concentrations of the tarsocrural joint (TCJ) or metatarsophalangeal joint (MTPJ) after standing saphenous IV regional limb perfusion (IVRLP) with 2 g of amikacin. Unassigned: 8 healthy adult horses underwent 4 saphenous IVRLP protocols with amikacin, differing in tourniquet type (pneumatic vs wide rubber) and number (1 placed mid-gaskin vs 1 placed mid-gaskin and 1 mid-metatarsus) in a randomized, crossover design. Amikacin concentrations were measured in serum and synovial fluid of the TCJ and MTPJ at 15 and 30...
Barton CK, Koch TG, Russell KA, Moorhead R, Mehrpouyan S, Alizadeh AH, Dow S, Pezzanite LM, Goodrich LR.To describe the case presentation, treatment, and outcome of horses treated with Toll-like receptor 3 (TLR-3)-activated allogeneic umbilical cord blood-derived mesenchymal stromal cells (CB-MSCs). Unassigned: 3 horses presenting with chronic or antimicrobial-resistant (AMR) septic synovitis. Unassigned: All horses presented with clinical signs associated with septic synovitis including marked grade 4/5 lameness, joint effusion, heat/swelling of the limb, and synovial fluid parameters consistent with sepsis. Case 1 presented 3 weeks following the onset of clinical signs. Cases 2 and 3 developed...
Barton CK, Nelson BB, Goodrich LR.Articular cartilage lesions represent a significant career-limiting problem in athletic horses. A healthy articular cartilage surface is vital for optimal joint function, and defects can result in irreversible degenerative changes. Successful treatment of cartilage lesions remains a long-standing challenge for orthopaedic surgeons, prompting ongoing research into new surgical techniques for their management. This narrative review describes surgical procedures for the treatment of cartilage/osteochondral lesions, as well as the use of the horse as a highly translational preclinical model to hum...
Harbowy RM, Robison CI, Tillman I, Manfredi JM, Nielsen BD.Oral joint supplements (OJSs), specifically those containing glucosamine and chondroitin sulfate, are some of the most popular feed additives fed by horse owners. However, evidence of the efficacy of these nutraceuticals in vivo is lacking. To investigate the impacts of an OJS on equine lameness, 40 geldings (18 ± 7 yr) with chronic lameness and AAEP lameness grades between 2 and 4 (as scored by a veterinary sports medicine and rehabilitation specialist) were enrolled in the study. Horses were stratified by lameness grade, BCS, and weight, and then randomly assigned to receive a placebo powde...
Anishchenko S, Bills KW, Beylin D, Beylin N, Beylin D, Stepanova K, Stepanov P, Spriet M.To create a labeled dataset and evaluate a convolutional neural network (CNN) for segmentation of fluorine-18 sodium fluoride PET scans of the equine metacarpo- and metatarsophalangeal joint (fetlock), targeting the third metacarpal bone, proximal phalanx, proximal sesamoid bone(s), and soft tissue. Unassigned: PET and corresponding CT scans were retrospectively selected from June 2024 through November 2025 using convenience sampling and coregistered to a common reference frame. The coregistered PET-CT scans were manually labeled; the labels were then transferred to PET-only images and used to...
Wang T, San Juan MR, Choi H, Hwang M, Jinadatha C, Navarathna DH. subspecies (SESZ) is an uncommon zoonotic pathogen in humans but can cause severe joint infections. Reported cases are often linked to exposure to horses, dairy products, or raw pork, though infections may occur without an identifiable animal source. Unassigned: An 84-year-old man with multiple comorbidities presented with acute left shoulder pain, fever, and chills. Synovial fluid aspiration yielded turbid fluid containing calcium pyrophosphate dihydrate crystals, while Gram stain was negative. Despite empiric broad-spectrum antibiotics, his symptoms persisted, requiring surgical irrigation...
Quintão NLM, Moffa EB, Kroier M, Goldoni RC, Bundgaard L, Jensen AL, Fernandes ES.Osteoarthritis (OA) is a chronic and progressive joint disease that can cause permanent loss of joint function. OA is highly prevalent in horses, dogs, and cats, affecting different joints and leading to reduced mobility and chronic pain. Different risk factors for animal OA have been identified, including trauma and breed. Inflammation is a hallmark of the disease, with various underlying mechanisms such as cyclooxygenase and metalloproteinase activation, nerve growth factor, cytokine, and prostaglandin upregulation, among others. Although disease complexity makes OA difficult to treat, eno...
Jasiński T, Zdrojkowski Ł, Turek B, Kaczorowski M, Pawliński B, Brehm W, Domino M.Computed tomography (CT) is used to support the diagnosis of equine temporomandibular joint (TMJ) disease; however, its diagnostic accuracy remains unclear. This study aimed to evaluate the relationship between CT findings and histopathological manifestations of osteoarthritis (OA) in equine TMJs. A total of 82 TMJs were CT-imaged, sampled, grouped into age-related and OA-related groups, and analyzed for frequency distributions, correlations, and CT-based TMJ OA diagnosis. CT findings were observed in 79% of joints, including 'CT anatomical variations' considering to reflect age-related remode...
Liso G, Winter K, Triebe TJ, Ulrich R, Brehm W, Wagner B, Schnabel CL, Troillet A, Roth SP.Synovial macrophages' role in equine osteoarthritis (OA) is not well understood, despite horses being a model for human degenerative joint disorders. Equine synovial macrophages' characterization is limited and age-related changes are not described. This study aimed to evaluate surface marker distribution and expression from potential synovial tissue macrophages in foals, adult non-affected, and OA-affected horses. Unassigned: Surface markers (CD14, CD16, CD206) were quantitatively evaluated on dorsal villous synovial biopsies from the metacarpophalangeal joint of foals (F), non-affected (cont...
Lopez DE, Carmalt JL.The equine temporomandibular joint (TMJ) is divided into two non-communicating joint (discotemporal DTJ and discomandibular DMJ) compartments. Ultrasound has been extensively used as a diagnostic tool in the horse, but previous work has reported that ultrasound-guidance did not improve the success rate of TMJ arthrocentesis. However, this research focused only on the larger, easily accessed, DTJ compartment. However, most of the osseous pathology of the equine TMJ has been reported to be in the smaller DMJ. Unassigned: To determine whether using ultrasound-guidance would reduce the number of a...
