Subchondral bone refers to the layer of bone just beneath the cartilage in the joints of horses. It plays a role in supporting the overlying cartilage and distributing loads across the joint surface during movement. Changes or damage to the subchondral bone can affect joint function and are often associated with conditions such as osteoarthritis. In horses, the health of subchondral bone is of interest for understanding joint disorders and improving lameness diagnosis and management. This page compiles peer-reviewed research studies and scholarly articles that examine the structure, function, and pathological changes of subchondral bone in equine joints.
Svalastoga E.Microangiographical investigations of the navicular bone in horses with navicular disease show, compared to similar investigations of normal navicular bones, that, in general, the vascular pattern is preserved but the vessels are dilated with "pooling" of the contrast medium subchondrally under facies flexoria. Similar changes may be observed in cases of human arthrosis. The present investigation therefore supports the view that navicular disease is a disease which resembles arthrosis.
Svalastoga E, Smith M.The subchondral bone pressure in the navicular bone of horses with navicular disease is compared with corresponding pressures in normal horses. An increased intraosseous pressure and a lengthened pressure drop time was demonstrated in patients with navicular disease, which indicates the existence of a venous stasis. Compared with similar investigations in humans with arthrosis it is concluded that navicular disease is a condition resembling arthrosis. The classical clinical symptoms are explained as an expression of resting pains. Treatments are suggested which theoretically can render the pat...
Verschooten F, De Moor A.Twenty-nine horses were examined over a period of 8 years and found to have cystic lesions in the stifle (14 cases) or pedal bone (15 cases). The lesions are described and illustrated with radiographs. In the stifle 12 lesions were found on the femoral condyles (11 medially and one laterally) and 10 were typical subchondral cysts. One lesion was observed in the tibia and 3 in the patella. Bone cysts wee found unilaterally in the pedal bone (14 in the forelimbs and one in the hindlimb). All but 2 of the horses with lesions in the stifle or pedal bone were lame. The only treatment was rest. For ...
Jeffcott LB, Kold SE.The clinical and radiological characteristics of stifle lameness in 86 horses are described. The majority of these cases had been lame for some weeks before referral. The most frequent diagnoses made were osteochondrosis dissecans (13 per cent) and subchondral bone cyst (38 per cent). Both of these conditions were seen principally in Thoroughbreds at or before the onset of training. The other bone lesions encountered were osteoarthritis (3 per cent), fractures (4 per cent) and "epiphysitis" (1 per cent). The commonest soft tissue condition was an atypical or partial upward fixation of the pate...
Jeffcott LB, Kold SE.Thirty-three cases with subchondral bone cysts in the stifle are reported. The condition was most commonly seen in young Thoroughbreds and produced intermittent lameness of varying degree. Radiographically distinct areas of radiolucency were found in the distal femur or proximal tibia adjacent to the femorotibial joint. Lesions were usually unilateral but 5 horses had cysts in both stifles. The cases could be divided into 2 distinct groups. Horses in Group A (28 cases) had a large circular or dome-shaped cyst in the medial femoral condyle with a distinct communication with the femorotibial joi...
O'Brien TR, Hornof WJ, Meagher DM.Subchondral lesions were identified in the distal palmar region of the third metacarpus in 21 fetlock joints of 15 Thoroughbred horses. The lesions were more commonly identified on the lateromedial and flexed lateral projection, with the flexed lateral projection permitting optimal visualization of the lesion. Lesions appeared as poorly marginated, radiolucent defects and were located at the level of the base of the proximal sesamoid bones. The shape and distribution of the radiolucent defects were: crescent, 4; flattened, 4; shallow concavity, 5; deep concavity, 3; oval, 3; and circular, 2. S...
Rejnö S, Strömberg B.An investigation was made of the pathology of osteochondritis dissecans of young foals and horses with clinical signs of the lesion. A randomly selected material of fetuses and young foals without clinical signs was also examined. It was demonstrated that osteochondritis dissecans is primarily a cartilaginous disease, as previously described in pigs and dogs. Thickening, disturbance of endochondral ossification, degeneration and necrosis of the cartilage were the four main features of osteochondritis dissecans. Cracks and fissures occurred in the degenerated and necrotic parts of the cartilage...
Malekipour F, Whitton RC, Lee PV.This review synthesizes recent advancements in understanding subchondral bone (SCB) biomechanics using computed tomography (CT) and micro-computed tomography (micro-CT) imaging in large animal models, particularly horses. Results: Recent studies highlight the complexity of SCB biomechanics, revealing variability in density, microstructure, and biomechanical properties across the depth of SCB from the joint surface, as well as at different joint locations. Early SCB abnormalities have been identified as predictive markers for both osteoarthritis (OA) and stress fractures. The development of sta...
Beck C, Hitchens PL, Whitton RC.Post-mortem studies have shown that fractures involving the metacarpophalangeal/metatarsophalangeal or fetlock joint are associated with focal areas of microdamage. Identification of computed tomography (CT) features consistent with microdamage and their association with fracture may aid in identification of horses at risk of fracture. Objective: To identify CT features associated with fracture of the metacarpophalangeal/metatarsophalangeal joint. Methods: Retrospective cohort study. Methods: Post-mortem CT images of 367 limbs from 157 Thoroughbred racehorses were graded for CT features. Multi...
Röschmann J, Naef J, Doras C, Gerber V.Equine asthma is a common cause of poor performance, but little is known about its impact on submaximal exercise. The aim of the present study was to evaluate the effects of equine asthma and potential confounding factors on recovery of respiratory rate (RR) and heart rate (HR) after a lunging exercise test. Thirty-seven horses completed a standardized 15 min lunging exercise including HR and RR recording pre- and up to 30 min post-exercise and venous blood lactate measurement. Endoscopy was performed and bronchoalveolar lavage fluid cytology was used to categorize horses as controls or asthma...
Nagy A, Dyson SJ.There is no description of comparative magnetic resonance imaging (MRI) and fan-beam computed tomography (CT) findings in the fetlock of lame sports horses. Objective: To document low-field MRI and fan-beam CT diagnoses in the lame and nonlame limbs of sports horses with fetlock region pain, and to evaluate whether combined imaging provides superior information to either technique alone. Methods: Retrospective descriptive study. Methods: Clinical records of sports horses with pain causing lameness localised to the metacarpo/metatarsophalangeal joint region that had undergone fan-beam CT and lo...
Ciamillo SA, Bills KW, Gassert TM, Richardson DW, Brown KA, Stefanovski D, Ortved KF.Stress-induced bone injury can lead to catastrophic injuries in Thoroughbred racehorses. Accumulation of high-speed exercise can increase the risk of subchondral bone injury. Objective: To investigate the effect of high-speed exercise on the subchondral bone of the metacarpo-metatarsophalangeal (MCP/MTP) joints using standing cone-beam computed tomography (CBCT) in young racing Thoroughbreds. Methods: Observational cohort study. Methods: Forty-one 2-year-old Thoroughbred racehorses during their first year of training were evaluated at 0, 6 and 12 months. Horses were evaluated for lameness an...
Solum G, Acutt E, Johnson SA, Zhou T, Contino EK, Donnell JR, Donnell A, Frisbie DD.Pathological changes of the fetlock joint are well documented in Thoroughbreds, but little information is available describing the common radiographic findings in western performance horses with fetlock lameness. Objective: To describe radiographic findings in western performance horses with fetlock lameness. It was hypothesised that the degree of lameness would correlate with the severity of radiographic findings. Methods: Retrospective case series. Methods: Retrospective review (2012-2022) of horses with lameness isolated to the fetlock joint via intra-articular analgesia and corresponding r...
Pál Z, Tuska P, Vásárhelyi G, Hangody L, Hurtig M, Kaposi AD, Bodó G.To evaluate the clinical application of equine mosaic arthroplasty for joint surface repair, including outcomes and complications. Methods: Retrospective clinical study. Methods: A total of 31 horses diagnosed with subchondral bone cysts (SBCs) in the femoral condyle (22/31), distal metacarpus (7/31), or metatarsus (2/31). Methods: Medical records of horses that underwent autologous or allogeneic osteochondral graft transplantation were reviewed. Follow-up lasted at least 12 months. Success was determined in terms of improvements in lameness and post-surgical athletic performance, classified...
Northwood A, Berner D.Radiographic protocols for the metacarpo-/tarsophalangeal joint during pre-purchase examinations (PPE) vary internationally, but their impact on pathology detection remains unclear. Optimising imaging protocols is essential to balance diagnostic accuracy with workflow efficiency and radiation exposure. Objective: To evaluate the effect of different radiographic view combinations on fetlock pathology detection and observer agreement in a PPE context; hypothesising that detection rates vary with view selection. Methods: Retrospective observational study. Methods: Two observers reviewed fetlock r...
