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.
Boado A, López-Sanromán FJ.Articular osteochondrosis (OC) is commonly reported in horses but there are no reports of its prevalence in the Spanish Purebred (SP). The objective of this study was to assess the prevalence and characteristics of OC of the tarsocrural, dorsal metacarpo-metatarsophalangeal and femoropatellar joints in the SP in a retrospective study. The data were obtained from the radiographs of 309 SP horses and the prevalence and characteristics of lesions were calculated. Osteochondral lesions at predilected sites were diagnosed in 48.8% of the horses. It was more common to find the presence of fragments ...
Bertuglia A, Lacourt M, Girard C, Beauchamp G, Richard H, Laverty S.The role of osteoclasts in osteochondral degeneration in osteoarthritis (OA) has rarely been investigated in spontaneous disease or animal models of OA. Objective: The objectives of the current study were to investigate osteoclast density and location in post-traumatic OA (PTOA) and control specimens from racehorses. Methods: Cores were harvested from a site in the equine third carpal bone, that undergoes repetitive, high intensity loading. Histological and immunohistochemical (Cathepsin K and Receptor-activator of Nuclear Factor kappa-β ligand (RANKL)) stained sections were scored (global an...
Mirams M, Ayodele BA, Tatarczuch L, Henson FM, Pagel CN, Mackie EJ.During the early stages of articular osteochondrosis, cartilage is retained in subchondral bone, but the pathophysiology of this condition of growing humans and domestic animals is poorly understood. A subtractive hybridization study was undertaken to compare gene expression between the cartilage of early experimentally induced equine osteochondrosis lesions and control cartilage. Of the many putative differentially expressed genes identified, eight were confirmed by quantitative PCR analysis as differentially expressed, in addition to those already known to be associated with early lesions. G...
Seo JP, Kambayashi Y, Itho M, Haneda S, Yamada K, Furuoka H, Tabata Y, Sasaki N.This study aimed to evaluate the efficacy of a synovial flap and gelatin/β-tricalcium phosphate (GT) sponge loaded with mesenchymal stem cells (MSCs), bone morphogenetic protein-2 (BMP-2), and platelet rich plasma (PRP) for repairing of osteochondral defects in horses. Osteochondral defects were created on the medial condyle of both femurs (n=5). In the test group, a GT sponge loaded with MSCs, BMP-2, and PRP (GT/MSCs/BMP-2/PRP) was inserted into the defect and then covered with a synovial flap. In the control group, the defect was treated only with the GT/MSCs/BMP-2/PRP. The test group showe...
McCoy AM.Osteoarthritis (OA) is unquestionably one of the most important chronic health issues in humans, affecting millions of individuals and costing billions of dollars annually. Despite widespread awareness of this disease and its devastating impact, the pathogenesis of early OA is not completely understood, hampering the development of effective tools for early diagnosis and disease-modifying therapeutics. Most human tissue available for study is obtained at the time of joint replacement, when OA lesions are end stage and little can be concluded about the factors that played a role in disease deve...
Laverty S, Lacourt M, Gao C, Henderson JE, Boyde A.We studied changes in articular calcified cartilage (ACC) and subchondral bone (SCB) in the third carpal bones (C3) of Standardbred racehorses with naturally-occurring repetitive loading-induced osteoarthritis (OA). Two osteochondral cores were harvested from dorsal sites from each of 15 post-mortem C3 and classified as control or as showing early or advanced OA changes from visual inspection. We re-examined X-ray micro-computed tomography (µCT) image sets for the presence of high-density mineral infill (HDMI) in ACC cracks and possible high-density mineralized protrusions (HDMP) from the ACC...
Bani Hassan E, Mirams M, Ghasem-Zadeh A, Mackie EJ, Whitton RC.To gain a better understanding of the aetiology of articular surface collapse in horses with palmar osteochondral disease. Objective: To determine whether acceleration of focal bone resorption associated with reduced physical activity contributes to articular surface collapse in racehorses with palmar osteochondral disease. Methods: Cross-sectional study comparing metacarpal bones from horses at varying stages of race training. Methods: Metacarpal bones from 36 racing Thoroughbred horses were examined with high-resolution peripheral quantitative computed tomography to determine the proportion ...
Peloso JG, Vogler JB, Cohen ND, Marquis P, Hilt L.To compare bony changes in the metacarpophalangeal joint (MCPJ) of racehorses with (cases) and without (controls) biaxial proximal sesamoid bone (PSB) fracture as determined by 2 grading scales applied to images of cadaveric forelimbs obtained by means of standing MRI (sMRI). Methods: Case-control study. Methods: Forelimbs from 74 Thoroughbred racehorses (21 cases and 53 controls) that were euthanized at a Florida racetrack. Methods: Both forelimbs were harvested from cases and controls. Each forelimb underwent sMRI to obtain images of the MCPJ. Two grading scales were described and used for i...
Olstad K, Østevik L, Carlson CS, Ekman S.Osteochondrosis arises as a result of focal failure of the blood supply to growth cartilage. The current aim was to examine the pathogenesis of pseudocysts and true cysts in subchondral bone following failure of the blood supply to the articular-epiphyseal cartilage complex in horses. Cases were recruited based on identification of lesions (n = 17) that were considered likely to progress to or to represent pseudocysts or true cysts in epiphyseal bone in histological sections and included 10 horses ranging in age from 48 days to 5 years old. Cases comprised 3 warmbloods, 3 Standardbreds, 1 Quar...
Desjardin C, Riviere J, Vaiman A, Morgenthaler C, Diribarne M, Zivy M, Robert C, Le Moyec L, Wimel L, Lepage O, Jacques C, Cribiu E, Schibler L.Osteochondrosis (OC(D)) is a juvenile osteo-articular disorder affecting several mammalian species. In horses, OC(D) is considered as a multifactorial disease and has been described as a focal disruption of endochondral ossification leading to the development of osteoarticular lesions. Nevertheless, OC(D) physiopathology is poorly understood. Affected horses may present joint swelling, stiffness and lameness. Thus, OC(D) is a major concern for the equine industry. Our study was designed as an integrative approach using omics technologies for the identification of constitutive defects in epiphy...
Miller RE, Grodzinsky AJ, Barrett MF, Hung HH, Frank EH, Werpy NM, McIlwraith CW, Frisbie DD.The goal of this study was to test the ability of an injectable self-assembling peptide (KLD) hydrogel, with or without microfracture, to augment articular cartilage defect repair in an equine cartilage defect model involving strenuous exercise. Methods: Defects 15 mm in diameter were created on the medial trochlear ridge and debrided down to the subchondral bone. Four treatment groups (n = 8 each) were tested: no treatment (empty defect), only defect filling with KLD, only microfracture, and microfracture followed by filling with KLD. Horses were given strenuous exercise throughout the one-ye...
MacKay AV, Panizzi L, Sparks HD, Barber SM.To report complications of arthrodesis of the carpometacarpal (CMC) joint using a drilling technique in an adult horse. Methods: Case report. Methods: Horse (n = 1). Methods: A 12-year-old Quarter Horse mare with CMC osteoarthritis (CMC-OA) had arthrodesis under general anesthesia in right lateral recumbency. Under fluoroscopic guidance, a 4.5 mm drill bit was inserted at 3 drilling sites 5-6 cm into the CMC joint and was fanned 30-45° in the plane of the joint and 5-10° in the long axis of the limb to destroy articular cartilage and expose the subchondral bone. Results: The horse pr...
Holmes JM, Mirams M, Mackie EJ, Whitton RC.Bone is repaired by remodelling, a process influenced by its loading environment. The aim of this study was to investigate the effect of a change in loading environment on bone remodelling by quantifying bone resorption and formation activity in the metacarpal subchondral bone in Thoroughbred racehorses. Sections of the palmar metacarpal condyles of horses in race training (n = 24) or resting from training (n = 24) were examined with light microscopy and back scattered scanning electron microscopy (BSEM). Bone area fraction, osteoid perimeter and eroded bone surface were measured withi...
Chevrier A, Kouao AS, Picard G, Hurtig MB, Buschmann MD.Microfracture repair tissue in young adult humans and in rabbit trochlea is frequently of higher quality than in corresponding ovine or horse models or in the rabbit medial femoral condyle (MFC). This may be related to differences in subchondral properties since repair is initiated from the bone. We tested the hypothesis that subchondral bone from rabbit trochlea and the human MFC are structurally similar. Trochlea and MFC samples from rabbit, sheep, and horse were micro-CT scanned and histoprocessed. Samples were also collected from normal and lesional areas of human MFC. The subchondral bone...
Desjardin C, Vaiman A, Mata X, Legendre R, Laubier J, Kennedy SP, Laloe D, Barrey E, Jacques C, Cribiu EP, Schibler L.MicroRNAs (miRNAs) are an abundant class of small single-stranded non-coding RNA molecules ranging from 18 to 24 nucleotides. They negatively regulate gene expression at the post-transcriptional level and play key roles in many biological processes, including skeletal development and cartilage maturation. In addition, miRNAs involvement in osteoarticular diseases has been proved and some of them were identified as suitable biomarkers for pathological conditions. Equine osteochondrosis (OC) is one of the most prevalent juvenile osteoarticular disorders in horses and represents a major concern f...
Trope GD, Ghasem-Zadeh A, Anderson GA, Mackie EJ, Whitton RC.High-resolution 3D imaging may improve the prediction and/or early identification of condylar fractures of the distal metacarpus/tarsus and reduce the frequency of breakdown injury in racehorses. Objective: To test the hypotheses that horses suffering condylar fractures have higher bone volume fraction (BV/TV) of the distal metacarpal epiphysis, greater subchondral bone thickness at the fracture site and higher second moment of inertia in the metacarpal midshaft as identified with high-resolution 3D imaging. Methods: Cross-sectional study using cadaver material. Methods: Thoroughbreds that die...
Dubois MS, Morello S, Rayment K, Markel MD, Vanderby R, Kalscheur VL, Hao Z, McCabe RP, Marquis P, Muir P.Articular stress fracture arising from the distal end of the third metacarpal bone (MC3) is a common serious injury in Thoroughbred racehorses. Currently, there is no method for predicting fracture risk clinically. We describe an ex-vivo biomechanical model in which we measured subchondral crack micromotion under compressive loading that modeled high speed running. Using this model, we determined the relationship between subchondral crack dimensions measured using computed tomography (CT) and crack micromotion. Thoracic limbs from 40 Thoroughbred racehorses that had sustained a catastrophic in...
Turley SM, Thambyah A, Riggs CM, Firth EC, Broom ND.The palmar aspect of the third metacarpal (MC3) condyle of equine athletes is known to be subjected to repetitive overloading that can lead to the accumulation of joint tissue damage, degeneration, and stress fractures, some of which result in catastrophic failure. However, there is still a need to understand at a detailed microstructural level how this damage progresses in the context of the wider joint tissue complex, i.e. the articular surface, the hyaline and calcified cartilage, and the subchondral bone. MC3 bones from non-fractured joints were obtained from the right forelimbs of 16 Thor...
Ley CJ, Ekman S, Hansson K, Björnsdóttir S, Boyde A.Osteochondral lesions in the joints of the distal tarsal region of young Icelandic horses provide a natural model for the early stages of osteoarthritis (OA) in low-motion joints. We describe and characterise mineralised and non-mineralised osteochondral lesions in left distal tarsal region joint specimens from twenty-two 30 ±1 month-old Icelandic horses. Combinations of confocal scanning light microscopy, backscattered electron scanning electron microscopy (including, importantly, iodine staining) and three-dimensional microcomputed tomography were used on specimens obtained with guidance f...
Desjardin C, Chat S, Gilles M, Legendre R, Riviere J, Mata X, Balliau T, Esquerré D, Cribiu EP, Betch JM, Schibler L.Osteochondrosis (OC) is a developmental bone disorder affecting several mammalian species including the horse. Equine OC is described as a focal disruption of endochondral ossification, leading to osteochondral lesions (osteochondritis dissecans, OCD) that may release free bodies within the joint. OCD lesions trigger joint swelling, stiffness and lameness and affects about 30% of the equine population. OCD is considered as multifactorial but its physiopathology is still poorly understood and genes involved in genetic predisposition are still unknown. Our study compared two healthy and two OC-a...
Harrison SM, Whitton RC, Kawcak CE, Stover SM, Pandy MG.The equine metacarpophalangeal (MCP) joint is frequently injured, especially by racehorses in training. Most injuries result from repetitive loading of the subchondral bone and articular cartilage rather than from acute events. The likelihood of injury is multi-factorial but the magnitude of mechanical loading and the number of loading cycles are believed to play an important role. Therefore, an important step in understanding injury is to determine the distribution of load across the articular surface during normal locomotion. A subject-specific finite-element model of the MCP joint was devel...
Martig S, Lee PV, Anderson GA, Whitton RC.In racehorses, fatigue related subchondral bone injury leads to overt fracture or articular surface collapse and subsequent articular cartilage degeneration. We hypothesised that the fatigue behaviour of equine subchondral bone in compression follows a power law function similar to that observed in cortical and trabecular bone. We determined the fatigue life of equine metacarpal subchondral bone in-vitro and investigated the factors influencing initial bone stiffness. Subchondral bone specimens were loaded cyclically in compression [54MPa (n=6), 66MPa (n=6), 78MPa (n=5), and 90MPa (n=6)] until...
Smith MR, Wright IM.Fractures of the proximal phalanx are generally considered to result from monotonic supraphysiological loads, but radiological observations from clinical cases suggest there may be a stress-related aetiology. Objective: To determine whether there are radiologically identifiable prodromal changes in Thoroughbred racehorses with confirmed parasagittal fractures of the proximal phalanx. Methods: Retrospective cross-sectional study. Methods: Case records and radiographs of Thoroughbred racehorses with parasagittal fractures of the proximal phalanx were analysed. Thickness of the subchondral bone p...
Olstad K, Hendrickson EH, Ekman S, Carlson CS, Dolvik NI.Describe the local morphological response of the articular-epiphyseal cartilage complex to surgical stab incision in the distal femur of foals, with emphasis on the relationship between growth cartilage injury, enchondral ossification, and repair. Methods: Nine foals were induced into general anesthesia at the age of 13 to 15 days. Four full-thickness stab incision defects were created in the cartilage on the lateral aspect of the lateral trochlear ridge of the left distal femur. Follow-up examination was carried out from 1 to 49 days postoperatively, including examination of intact bones, saw...
McIlwraith CW.The paper reviews current knowledge on conservative versus surgical options for the treatment of osteochondrosis entities in the horse. Clinical and radiographic signs of each significant osteochondrosis entity in the horse are presented, followed by the value of conservative treatment versus arthroscopic surgery options as well as the results for each option with the various entities. The entities presented in detail include, osteochondritis dissecans (OCD) of the femoropatellar, tarsocrural, metacarpophalangeal and metatarsophalangeal, and glenohumural articulations. The various treatment op...
Malekipour F, Whitton C, Oetomo D, Lee PV.Despite the important role of subchondral bone in maintaining the integrity of the overlying articular cartilage, little research has focused on measuring its mechanical behavior, particularly under injurious load conditions such as impact compression. In this study, the stiffness and the absorbed energy of subchondral bone were compared to that of its overlying cartilage by applying impact compression to equine cartilage-bone specimens. Deformations of the cartilage and subchondral bone were examined independently within the cartilage-bone unit by analyzing real-time images of cartilage-bone ...
Rautiainen J, Lehto LJ, Tiitu V, Kiekara O, Pulkkinen H, Brünott A, van Weeren R, Brommer H, Brama PA, Ellermann J, Kiviranta I, Nieminen MT....To evaluate the status of articular cartilage and bone in an equine model of spontaneous repair by using the sweep imaging with Fourier transform (SWIFT) magnetic resonance (MR) imaging technique. Methods: Experiments were approved by the Utrecht University Animal Ethics Committee. Six-millimeter-diameter chondral (n = 5) and osteochondral (n = 5, 3-4 mm deep into subchondral bone) defects were created in the intercarpal joints of seven 2-year-old horses and examined with SWIFT at 9.4 T after spontaneous healing for 12 months. Conventional T2 maps and gradient-echo images were obtained for com...
Walker WT, Kawcak CE, Hill AE.To characterize medial femoral condyle (MFC) morphometrics and subchondral bone density patterns in Thoroughbred racehorses and to determine whether these variables differ between left and right limbs. Methods: Stifle joints harvested from 6 Thoroughbred racehorses euthanized for reasons other than hind limb lameness. Methods: The distal portion of the left and right femurs of each cadaver was scanned via CT. Hounsfield units were converted to dipotassium phosphate equivalent densities through use of a phantom on each specimen. Medial femoral condyle width, length, height, and curvature; subch...
Ricard A, Perrocheau M, Couroucé-Malblanc A, Valette JP, Tourtoulou G, Dufosset JM, Robert C, Chaffaux S, Denoix JM, Guérin G.Juvenile osteochondral conditions (JOCC) have been defined as lesions resulting from biomechanical influences (compressive, tensional or shear forces) on the developing and growing musculoskeletal system. They include different types of osteochondrosis, osteochondral fragmentation of the articular surface or of the periarticular margins, juvenile subchondral bone cysts, osteochondral collapse, avulsion fractures of epiphyseal (or metaphyseal) ossifying bone and 'physitis'. The aim of this study was to estimate heritability of JOCC in a sample of 2106 French Trotters from four different sources...
Kim W, McArdle BH, Kawcak CE, McIlwraith CW, Firth EC, Broom ND.To investigate histomorphometric changes in the cartilage and subchondral bone of the third carpal bone associated with conditioning exercise in young Thoroughbreds. Methods: Nine 18-month-old Thoroughbreds. Procedures-Both third carpal bones of 9 horses (4 exercised spontaneously at pasture only and 5 given additional conditioning exercise beginning at a mean age of 3 weeks) were evaluated. Histomorphometric variables (hyaline and calcified cartilage thickness and collagen orientation; vascular channel area, number, and orientation; and osteochondral junction rugosity) of the third carpal bon...
Bertuglia A, Basano I, Pagliara E, Bottegaro NB, Spinella G, Bullone M.To compare the effects of tiludronate disodium and 3 other medical treatments on clinical and radiographic findings and biomarkers of disease progression in horses with osteoarthritis of the fetlock joint. 100 Standardbred racehorses with spontaneous traumatic injury of the fetlock joint. Horses were retrospectively grouped by whether they received tiludronate IV or triamcinolone acetonide and hyaluronan, polysulfated glycosaminoglycan, or interleukin-1 receptor antagonist protein intra-articularly. Data were collected on clinical, radiographic, and ultrasonographic findings and results for se...
Anastasiou A, Skioldebrand E, Ekman S, Hall LD.The distal row of carpal bones (C2, C3, and C4) from eight left intercarpal joints--four from Standardbred Trotters and four from Swedish Warmblood horses--were used to assess the potential of magnetic resonance (MR) imaging to detect cartilage and bone lesions. The joints used in the study were classified by macroscopic and radiographic examinations as having normal, mild, moderate, or severe articular cartilage lesions and bone sclerosis. Those classifications correlated well with the appearance of the MR images. Bone sclerosis in the MR images was observed as regions of decreased signal int...
Nixon AJ, Fortier LA, Goodrich LR, Ducharme NG.Debridement of osteochondritis dissecans (OCD) cartilage lesions results in fibrocartilage and imperfect hyaline repair tissue, and forms a permanent irregularity to the subchondral bone plate. Objective: To evaluate the clinical, radiographic and outcome effects of OCD cartilage flap reattachment for select lesions as an alternative to OCD debridement. Objective: Separated cartilage flaps resulting from OCD lesions may be re-incorporated into the hyaline cartilage surface by reattachment rather than debridement and removal. Methods: Resorbable polydioxanone pins were used to reattach OCD flap...
Ravanetti P, Lechartier A, Hamon M, Zucca E.In the last 30 years, several treatments have been proposed to treat subchondral cystic lesions (SCLs) but there have been no randomised studies to compare different methods and there is no consensus as to the optimal treatment. Objective: To evaluate a biocompatible absorbable implant for the treatment of SCLs in young horses in different anatomical locations. Methods: Retrospective case series. Methods: Horses with SCLs were treated with debridement through a trans-cortical extra-articular approach and an absorbable implant was inserted in the cavity. Clinical and radiographic follow-up was...
Malekipour F, Whitton CR, Lee PV.Subchondral bone injury due to high magnitude and repetition of compressive loading is common in humans and athletic animals such as Thoroughbred racehorses. Repeated loading of the joint surface may alter the subchondral bone microstructure and initiate microdamage in the bone adjacent to the articular cartilage. Understanding the relationship between microdamage, microstructure and mechanical properties of the subchondral bone adjacent to the articular cartilage is, therefore, essential in understanding the mechanism of subchondral bone injury. In this study, we used high-resolution µCT sca...
Rubio-Martínez LM, Cruz AM, Gordon K, Hurtig MB.To characterize the microstructure of subchondral bone (SCB) plate and trabecular bone (TBB) of the distopalmar aspect of the condyles of third metacarpal bones (MC3s) from Thoroughbred racehorses at 2 different stages of SCB disease via micro-computed tomography (CT). Methods: 12 pairs of MC3s from Thoroughbred racehorses euthanized for various reasons. Methods: MC3s were collected from horses with mild (n = 6) or severe (6) SCB disease, as determined via micro-CT. Cubic (6 x 6 x 6-cm) specimens of SCB plate and TBB were cut from the palmar aspect of condyles and sagittal ridges and examined ...
Schneider RK, Jenson P, Moore RM.To evaluate clinical findings and response to treatment in horses in which cartilage lesions on the medial femoral condyle were a cause of lameness. Methods: Retrospective case series. Methods: Medical records of 11 horses that had cartilage lesions on the medial femoral condyle detected during arthroscopy of the stifle. Methods: Signalment, history, lameness examination, response to intra-articular anesthesia, radiographs of the stifle, observations during diagnostic arthroscopy, and treatment were extracted from the medical record of each horse. Follow-up examinations and outcome were availa...
Smith MR, Wright IM.Fractures of the proximal phalanx are generally considered to result from monotonic supraphysiological loads, but radiological observations from clinical cases suggest there may be a stress-related aetiology. Objective: To determine whether there are radiologically identifiable prodromal changes in Thoroughbred racehorses with confirmed parasagittal fractures of the proximal phalanx. Methods: Retrospective cross-sectional study. Methods: Case records and radiographs of Thoroughbred racehorses with parasagittal fractures of the proximal phalanx were analysed. Thickness of the subchondral bone p...
Seo JP, Kambayashi Y, Itho M, Haneda S, Yamada K, Furuoka H, Tabata Y, Sasaki N.This study aimed to evaluate the efficacy of a synovial flap and gelatin/β-tricalcium phosphate (GT) sponge loaded with mesenchymal stem cells (MSCs), bone morphogenetic protein-2 (BMP-2), and platelet rich plasma (PRP) for repairing of osteochondral defects in horses. Osteochondral defects were created on the medial condyle of both femurs (n=5). In the test group, a GT sponge loaded with MSCs, BMP-2, and PRP (GT/MSCs/BMP-2/PRP) was inserted into the defect and then covered with a synovial flap. In the control group, the defect was treated only with the GT/MSCs/BMP-2/PRP. The test group showe...
Murray RC, Whitton RC, Vedi S, Goodship AE, Lekeux P.Carpal osteochondral injury is frequently observed in strenuously trained horses. It is clear that the integrity of articular cartilage and subchondral bone are intimately related, although there is controversy about which component is the most important. Calcified cartilage provides the mechanical link between soft hyaline cartilage and stiff subchondral bone so it is essential to understand the tissue's response to exercise. Middle carpal calcified and uncalcified (hyaline) cartilage thickness was investigated in horses undergoing high- and low-intensity exercise. Twelve untrained horses (18...
Drum MG, Kawcak CE, Norrdin RW, Park RD, McIlwraith CW, Les CM.Comparison of subchondral bone density determined by quantitative computed tomography (CT) with gross and histopathologic changes have not been made in horses. The goal of this study was to determine if mean quantitative CT density and mean voxel standard deviation are associated with the presence and severity of osteochondral lesions in the palmar aspect of the distal third metacarpal bone in racing horses. Metacarpophalangeal joints from nine racehorses were imaged using CT and scored for gross damage. Four-millimeter-thick sagittal and 30 degrees palmar dorsal plane sections were cut, decal...
Young BD, Samii VF, Mattoon JS, Weisbrode SE, Bertone AL.To evaluate and correlate patterns of subchondral bone density and articular cartilage degeneration (derived by use of gross, histologic, and computed tomographic [CT] examinations) in equine third metacarpal condyles with and without osteoarthritis. Methods: 8 metacarpophalangeal (MCP) joints (n = 4 horses) without osteoarthritis and 6 osteoarthritis-affected MCP joints (4). Methods: Horses were euthanized. The third metacarpal condyles of the joints were examined grossly and via CT (3 slice images/condyle). For 6 condylar zones, mean bone density and pattern of density distribution were dete...
De Lasalle J, Alexander K, Olive J, Laverty S.A better understanding of imaging characteristics of equine stifle osteoarthritis (OA) may allow earlier detection and improve prognosis. Objectives of this ex vivo, prospective, methods comparison study were to (1) describe the location and severity of naturally acquired OA lesions in the equine stifle using ultrasound (US), radiography (XR), computed tomography (CT), and macroscopic evaluation (ME); (2) compare the diagnostic performance of each imaging modality with ME; and (3) describe subchondral bone mineral density (BMD) in equine stifle joints with OA using CT. Radiographic, CT, and US...
Young DR, Richardson DW, Markel MD, Nunamaker DM.The third carpal bone (C3) was collected from both forelimbs of 27 Thoroughbreds. On the basis of age, training, and history, specimens were assigned to 1 of 5 groups: yearling, untrained horses (group 1, n = 4); 2- to 3-year-old, untrained horses (group 2, n = 7); trained 2-year-old horses (group 3, n = 6); trained 3-year-old horses (group 4, n = 6); and 3-year-old, trained horses with carpal pathologic features (group 5, n = 4). A transverse section of subchondral bone 5-mm thick was cut in a precise fashion 10 mm below the proximal articular surface of all specimens. After high-detail radio...
Brama PA, Bank RA, Tekoppele JM, Van Weeren PR.Subchondral bone provides structural support to the overlying articular cartilage and plays an important role in osteochondral diseases. There is growing insight that the mechanical features of bone are related to the biochemistry of the collagen network. In this study the effect of exercise on water, calcium and the collagen network (total collagen, lysyl-hydroxylation, hydroxylysylpyridinoline, and lysylpyridinoline crosslinks) of subchondral bone at two differently loaded sites (site 1: intermittently loaded; site 2: constantly loaded) is investigated in foals. Exercise influenced calcium c...
van der Harst M, Bull S, Brama PA, Barneveld AB, van Weeren PR, van de Lest C.Osteoarthritis (OA) is a chronic debilitating joint disorder in which the importance of inflammation is increasingly recognized. In advanced cases, both the articular cartilage and the underlying bony layers are affected, but the exact sequence of events and their localization in the initial phase of pathogenesis remain uncertain. We measured nitric oxide (NO) end products in tissue layers that constitute the bearing surface of the joint, as possible indicators of physiological and pathological processes. Methods: Nitrite as a measure for NO and nitrotyrosine was measured in articular cartilag...
Gilday R, Richard H, Beauchamp G, Fogarty U, Laverty S.The administration of bisphosphonate medications, which target osteoclastic-bone remodelling, to juvenile and adult racehorses is a matter of debate owing to concerns that these molecules remain bound to the bone-mineralised matrix and may interfere with subsequent bone growth, adaptation to exercise and healing of bone microdamage in equine athletes. Osteoclasts participate in endochondral ossification, subchondral bone remodelling and bone repair. There is a knowledge gap on the role of equine osteoclast biology in the growth and maturation of joint surfaces and this information is important...
Kawcak CE, McIlwraith CW, Firth EC.To determine the effects of exercise at an early age on tissues in the metacarpophalangeal joints of horses. Methods: Twelve 18-month-old horses. Methods: All horses were pasture reared, but 6 horses had additional exercise starting at 3 weeks of age until 18 months of age. At that time, computed tomography, articular cartilage metabolism evaluation, and histologic assessments of synovial membrane, articular cartilage, and subchondral bone were performed. Results: Exercised horses had fewer gross lesions, less articular cartilage matrix staining in the dorsal aspect of the condyle, greater bon...
Frazer LL, Santschi EM, Fischer KJ.To predict bone and medial meniscal stresses and contact pressures in an equine stifle with a medial femoral condyle (MFC) intact or with a 2-cm subchondral bone void, under varying degrees of internal femoral rotation (IFR). Methods: Finite element model (FEM) of a cadaveric equine stifle loaded to 8000 N. Methods: The FEM was constructed from computed tomography (CT) of the right, extended stifle of a yearling. The CT image was segmented into relevant anatomic structures and meshed into 4-node tetrahedrons. Bone material properties were assigned according to Hounsfield units, soft tissue p...
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...
Peat FJ, Kawcak CE, McIlwraith CW, Keenan DP, Berk JT, Mork DS.Subchondral lucencies (SCLs) in the distal aspect of the medial femoral condyle (MFC) of young Thoroughbred horses are a source of controversy on presale radiographs. There is limited scientific evidence regarding the risk of progression and impact on future racing performance. Objective: To (1) identify the prevalence of MFC SCLs on sales repository radiographs in yearling and 2-year-old Thoroughbreds; (2) identify any association between grade of MFC SCL and future racing performance and (3) monitor changes in MFC SCL grades between yearling and 2-year-old sales. Methods: Prospective cohort ...
Firth EC, Doube M, Boyde A.To show that changes are present at the site of origin of metacarpal condylar fracture in young Thoroughbred horses before they enter race training. Methods: Bone slices, 2 mm thick, in three mediolateral planes through the centre of rotation of the metacarpo-phalangeal joint (MCPJ) of both distal third metacarpal bones (Mc3) of 12 Thoroughbred horses aged 17 months, were imaged using point-projection digital X-ray imaging (muXR). Results: In some horses, linear or ovoid radiolucency was found in articular calcified cartilage (ACC) and subchondral bone of the palmaro-distal aspect of the sagit...
Luedke LK, Ilevbare P, Noordwijk KJ, Palomino PM, McDonough SP, Palmer SE, Basran PS, Donnelly E, Reesink HL.To determine whether proximal sesamoid bone (PSB) microdamage and fracture toughness differ between Thoroughbred racehorses sustaining PSB fracture and controls. Methods: Cadaveric case-control. Methods: Twenty-four Thoroughbred racehorses (n = 12 PSB fracture, n = 12 control). Methods: Proximal sesamoid bones were dissected, and gross pathological changes and morphological measurements were documented. High-speed exercise history data were evaluated. Microdamage was assessed in fracture, fracture-contralateral limb (FXCL) and control PSBs using whole bone lead uranyl acetate (LUA) stainin...
Mizobe F, Nomura M, Ueno T, Yamada K.This study focused on 8 Thoroughbred racehorses showing bone marrow oedema-type signal in the proximal sagittal groove of the proximal phalanx, with the aim of understanding its clinical significance. Standing magnetic resonance imaging played an important role in assessing osseous abnormalities that were not radiographically identifiable. Further, a histopathological result from one of the cases showed there was oedema surrounding adipose tissues with increase in density of trabecular scaffolding. This may indicate presence of osseous injury within the area of decreased elasticity due to subc...
Hanson JA, Seeherman HJ, Kirker-Head CA, O'Callaghan MW.Seven horses with severe, persistent lameness of sudden onset were evaluated with scintigraphy and/or computed tomography. The lameness was localised to the front fetlock joint in 2 horses and to the tibiotarsal joint in 5 horses. Five of the horses had a history of intra-articular injections of the involved joint prior to presentation. All horses had effusion of the affected joint and were positive to flexion tests. Intraarticular anaesthesia eliminated or improved the lameness in 4 cases and a nerve conduction block proximal to the affected joint improved the lameness in another. Cytology ex...
Bras JJ, Lillich JD, Beard WL, Anderson DE, Armbrust LJ, Frink E, Lease K.To (1) compare the effect of a collateral ligament sparing surgical approach with an open surgical approach on mechanical properties of proximal interphalangeal joint (PIPJ) arthrodesis, and (2) to determine the percentage of articular cartilage surface removed by transarticular (TA) drilling with different diameter drill bits. Methods: Randomized paired limb design. Methods: Cadaveric equine limbs (n=76). Methods: Cadaveric PIPJ were drilled using a 3.5, 4.5, or 5.5 mm drill bit at 80-84° to the dorsal plane to remove articular cartilage and subchondral bone from the distal articular surface...
Kulmala KA, Pulkkinen HJ, Rieppo L, Tiitu V, Kiviranta I, Brünott A, Brommer H, van Weeren R, Brama PA, Mikkola MT, Korhonen RK, Jurvelin JS....Contrast-enhanced computed tomography (CECT) has been introduced for the evaluation of cartilage integrity. Furthermore, CECT enables imaging of the structure and density of subchondral bone. In this laboratory study, we investigate the potential of microCECT to simultaneously image cartilage and subchondral bone for the evaluation of tissue healing. Methods: Osteochondral lesions (Ø = 6 mm) were surgically created in equine intercarpal joints (n = 7). After spontaneous healing for 12 months, the horses were sacrificed and osteochondral plugs (Ø = 14 mm), including the repair cartilage and a...
Murray RC, Branch MV, Dyson SJ, Parkin TD, Goodship AE.Adaptation of osteochondral tissues is based on the strains experienced during exercise at each location within the joint. Different exercise intensities and types may induce particular site-specific strains, influencing osteochondral adaptation and potentially predisposing to injury. Our hypotheses were that patterns of equine distal tarsal subchondral bone (SCB) thickness relate to the type and intensity of exercise, and that high-intensity exercise leads to site-specific increases in thickness. SCB thickness was measured at defined dorsal and plantar locations on magnetic resonance images o...
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...
Arbabi V, Pouran B, Weinans H, Zadpoor AA.Investigation of the solute transfer across articular cartilage and subchondral bone plate could nurture the understanding of the mechanisms of osteoarthritis (OA) progression. In the current study, we approached the transport of neutral solutes in human (slight OA) and equine (healthy) samples using both computed tomography and biphasic-solute finite element modeling. We developed a multi-zone biphasic-solute finite element model (FEM) accounting for the inhomogeneity of articular cartilage (superficial, middle and deep zones) and subchondral bone plate. Fitting the FEM model to the concentra...
