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.
Mouloodi S, Rahmanpanah H, Gohari S, Burvill C, Tse KM, Davies HMS.Artificial intelligence (AI) and machine learning (ML) are fascinating interdisciplinary scientific domains where machines are provided with an approximation of human intelligence. The conjecture is that machines are able to learn from existing examples, and employ this accumulated knowledge to fulfil challenging tasks such as regression analysis, pattern classification, and prediction. The horse biomechanical models have been identified as an alternative tool to investigate the effects of mechanical loading and induced deformations on the tissues and structures in humans. Many reported invest...
Lemirre T, Santschi EM, Girard CA, Fogarty U, Janes JG, Richard H, Laverty S.The aetiology of equine medial femoral condyle (MFC) subchondral bone radiolucencies (SR) is unknown. Objective: Characterise the microstructural structural features of MFC SR in juvenile Thoroughbreds with microcomputed tomography (μCT) and histology. Methods: Cross-sectional post-mortem study. Methods: Distal femurs were collected at post-mortem. Conventional tomodensitometry was employed to scout for MFCs with and without SR lesions (SR+ and SR-, respectively). Group 1 were CT MFC SR+ and Group 2 age-matched SR- controls. Both underwent μCT and histological analysis. Group 3 CT MFC SR- fo...
Zanotto GM, Liesbeny P, Barrett M, Zlotnick H, Frank E, Grodzinsky AJ, Frisbie DD.Microfracture augmentation can be a cost-effective single-step alternative to current cartilage repair techniques. Trypsin pretreatment combined with a growth factor-functionalized self-assembling KLD hydrogel ("functionalized hydrogel") has been shown to improve overall cartilage repair and integration to surrounding tissue in small animal models of osteochondral defects. Microfracture combined with trypsin treatment and a functionalized hydrogel will improve reparative tissue quality and integration as compared with microfracture alone in an equine model. Controlled laboratory study. Bilater...
Boyde A.This review describes results obtained with tissue from prior studies of equine and human osteoarthritis (OA). The main methods considered are scanning electron microscopy, novel methods in light microscopy and X-ray Micro-tomography. The same samples have been re-utilised in several ways. The tissues described are hyaline articular cartilage (HAC; or substitutes), with its deep layer, articular calcified cartilage (ACC), whose deep surface is resorbed in cutting cone events to allow the deposition of subchondral bone (SCB). Multiple tidemarks are normal. Turnover at the osteochondral (ACC-HAC...
Turlo AJ, McDermott BT, Barr ED, Riggs CM, Boyde A, Pinchbeck GL, Clegg PD.Osteoarthritis (OA) is a disease of the entire joint but the relationship between pathological events in various joint tissues is poorly understood. We examined concurrent changes in bone, cartilage, and synovium in a naturally occurring equine model of joint degeneration. Joints (n = 64) were grossly assessed for palmar/plantar osteochondral disease (POD) in racehorses that required euthanasia for unrelated reasons and assigned a grade of 0 (n = 34), 1 (n = 17), 2 or 3 (n = 13) using a recognized grading scheme. Synovium, cartilage, and subchondral bone were collected for hist...
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...
Te Moller NCR, Mohammadi A, Plomp S, Serra Bragança FM, Beukers M, Pouran B, Afara IO, Nippolainen E, Mäkelä JTA, Korhonen RK, Töyräs J....This study aimed to quantify the long-term progression of blunt and sharp cartilage defects and their effect on joint homeostasis and function of the equine carpus. In nine adult Shetland ponies, the cartilage in the radiocarpal and middle carpal joint of one front limb was grooved (blunt or sharp randomized). The ponies were subjected to an 8-week exercise protocol and euthanized at 39 weeks. Structural and compositional alterations in joint tissues were evaluated in vivo using serial radiographs, synovial biopsies, and synovial fluid samples. Joint function was monitored by quantitative gait...
Curtiss AL, Ortved KF, Dallap-Schaer B, Gouzeev S, Stefanovski D, Richardson DW, Wulster KB.Subchondral bone pathology is common in Thoroughbred racehorses and believed to precede more serious injury. Early identification of pathology is critical to allow for intervention. Objective: To determine interobserver variability of fetlock subchondral bone lesions using cone beam and fan beam computed tomography (CBCT, FBCT) and to validate a robotics-controlled CBCT to identify fetlock subchondral bone pathology in the Thoroughbred racehorse. Methods: Prospective cohort study. Methods: FBCT and CBCT images were acquired of 25 metacarpo-/metatarsophalangeal joints of Thoroughbred racehorses...
Santschi EM, Juzwiak JS, Honnas C, Walker WT, Hunter B, Whitman JL, Prichard MA, Morehead JP.The objective of this study is to describe the management and outcomes of eight horses with subchondral lucencies (SCLs) of the medial aspect of the antebrachiocarpal (ABC) joint. The medical records and radiographs of the carpi of 8 horses with SCLs of the medial aspect of the ABC joint were reviewed. Follow-up clinical information was obtained for 6-60 months (the median duration of 14 months). Treatment was successful if radiographic healing was apparent or lameness was reduced or eliminated. Four horses had SCLs in the distomedial radius (DMR) and four in the proximal aspect of the radio...
Golonka P, Kornicka-Garbowska K, Marycz K.Stem cell based therapy are now commonly applied in human and veterinary medical practice especially in orthopaedics. Mesenchymal stromal stem cells isolated from adipose tissue (ASC) are first choice option due to relatively non-invasive and safe procedure of tissue harvesting. However, ASC therapeutic potential strongly rely on patients general health condition, age and life-style. For that reason, to enhance therapeutic potential of cells, they are modified in vitro using different approaches. Previous studies have shown, that ASC treated with resveratrol, herein called SIRT+, are character...
Anderson JR, Phelan MM, Foddy L, Clegg PD, Peffers MJ.Osteoarthritis is an age-related degenerative musculoskeletal disease characterized by loss of articular cartilage, synovitis, and subchondral bone sclerosis. Osteoarthritis pathogenesis is yet to be fully elucidated with no osteoarthritis-specific biomarkers in clinical use. equine cartilage explants ( = 5) were incubated in tumor necrosis factor-α (TNF-α)/interleukin-1β (IL-1β)-supplemented culture media for 8 days, with the media removed and replaced at 2, 5, and 8 days. Acetonitrile metabolite extractions of 8 day cartilage explants and media samples at all time points underwent one-d...
Shaffer SK, To C, Garcia TC, Fyhrie DP, Uzal FA, Stover SM.Proximal sesamoid bone (PSB) fracture is the most common fatal injury in Thoroughbred (TB) racehorses in the United States. Epidemiological and pathological evidence indicates PSB fracture is likely the acute culmination of a chronic stress-related process. However, the aetiopathogenesis of PSB fracture is poorly understood. Objective: To characterise bone abnormalities that precede PSB fracture. Methods: Two retrospective case-control groups of PSBs from TB racehorses with, and without, unilateral biaxial PSB fracture. Methods: Proximal sesamoid bones were harvested post-mortem from TB raceho...
Shaktivesh S, Malekipour F, Whitton RC, Hitchens PL, Lee PV.Fatigue-induced subchondral bone (SCB) injuries are prevalent among athletes due to the repetitive application of high magnitude loads on joints during intense physical training. Existing fatigue studies on bone utilize a standard fatigue test approach by applying loads of a constant magnitude and frequency even though physiological/realistic loading is a combination of various load magnitudes and frequencies. Metal materials in implant and aerospace applications have been studied for fatigue behavior under physiological or realistic loading, however, no such study has been conducted on biolog...
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...
Santschi EM, Whitman JL, Prichard MA, Lopes MAF, Pigott JH, Brokken MT, Jenson PW, Johnson CR, Morrow C, Brusie RW, Juzwiak JS, Morehead JP.To describe subchondral lucencies (SCL) in the equine proximal tibia, several treatment options, and clinical outcomes. Methods: Retrospective study. Methods: Seventeen horses with proximal tibial SCL. Methods: Medical record and radiograph review. Follow-up was obtained via examination and radiography when possible and by telephone and race records when required. The median duration of follow-up was 20 months (range, 0-48). Results: Proximal tibial SCL were associated with lameness in 14 of 17 horses. Subchondral lucencies were primary in 11 horses and secondary to an ipsilateral medial fem...
Lemirre T, Santschi E, Girard C, Fogarty U, Chapuis L, Richard H, Beauchamp G, Laverty S.The juvenile equine medial femoral condyle (MFC) is frequently affected with radiographic changes (sclerosis and subchondral lucencies) that arise at a similar site to juvenile osteochondritis dissecans (JOCD) in children. There is little information on maturation of the MFC. To describe the normal development of the equine MFC osteochondral unit from birth to 2 years. Unassigned: Micro CT, histology and immunohistochemistry were performed on healthy equine MFCs (n = 29) at sites where lesions occur. Parameters assessed included: cartilage thickness; the epiphyseal growth plate cartilage org...
Journal of biomechanicsDecember 24, 2019
Volume 100 109594 doi: 10.1016/j.jbiomech.2019.109594
Malekipour F, Hitchens PL, Whitton RC, Lee PV.Subchondral bone (SCB) microdamage is prevalent in the joints of human athletes and animals subjected to high rate and magnitude cyclic loading of the articular surface. Quantifying the effect of such focal in vivo fatigue-induced microdamage on the mechanical response of the tissue is critical for the understanding of joint surface injury and the development of osteoarthritis. Thus, we aimed to quantify the mechanical properties of cartilage-bone from equine third metacarpal (MC3) condyles, which is a common area of accumulated microdamage due to repetitive impact loading. We chose a non-dest...
Kemper AM, Drnevich J, McCue ME, McCoy AM.Skeletogenesis is complex and incompletely understood. Derangement of this process likely underlies developmental skeletal pathologies. Examination of tissue-specific gene expression may help elucidate novel skeletal developmental pathways that could contribute to disease risk. Our aim was to identify and functionally annotate differentially expressed genes in equine neonatal and adult articular cartilage (AC) and subchondral bone (SCB). RNA was sequenced from healthy AC and SCB from the fetlock, hock, and stifle joints of 6 foals (≤4 weeks of age) and six adults (8-12 years of age). There w...
Mazzotti E, Teti G, Falconi M, Chiarini F, Barboni B, Mazzotti A, Muttini A.Osteoarthritis is a degenerative disease that strongly correlates with age and promotes the breakdown of joint cartilage and subchondral bone. There has been a surge of interest in developing cell-based therapies, focused particularly on the use of mesenchymal stromal cells (MSCs) isolated from adult tissues. It seems that MSCs derived from synovial joint tissues exhibit superior chondrogenic ability, but their unclear distribution and low frequency actually limit their clinical application. To date, the influence of aging on synovial joint derived MSCs' biological characteristics and differen...
Martig S, Hitchens PL, Lee PVS, Whitton RC.Subchondral bone injuries often precede articular cartilage damage in osteoarthritis and are common in thoroughbred racehorses due to the accumulation of fatigue damage from high speed racing and training. Thus, racehorses provide a model to investigate the role of subchondral bone in joint disease. We assessed the association of horse and racing related factors and micro-CT based micromorphology of three separate subchondral bone layers with the initial stiffness and compressive fatigue life of bone plugs. Furthermore, we investigated three different definitions of fatigue failure of subchond...
Shaktivesh , Malekipour F, Whitton C, Lee PVS.Standard fatigue testing of bone uses a single load and frequency applied until failure. However, in situ, the subchondral bone of Thoroughbred racehorses is subjected to a combination (or a spectrum) of loads and frequencies during training and racing. Objective: To investigate the use of a fatigue testing method for equine third metacarpal (McIII) subchondral bone under a spectrum of loading conditions which a racehorse is likely to experience during a fast workout. Methods: In vitro biomechanical experimental study. Methods: McIII subchondral bone specimens (n = 12) of racehorses were ha...
Zellmann P, Ribitsch I, Handschuh S, Peham C.We developed a finite element model (FEM) of the equine stifle joint to identify pressure peaks and simulate translocation and deformation of the menisci. A series of sectional magnetic resonance images (1.5 T) of the stifle joint of a 23 year old Shetland pony gelding served as basis for image segmentation. Based on the 3D polygon models of femur, tibia, articular cartilages, menisci, collateral ligaments and the meniscotibial ligaments, an FEM model was generated. Tissue material properties were assigned based on data from human (Open knee(s) project) and bovine femoro-tibial joint available...
Di Filippo PA, Dias Meireles MA, Ribeiro LMF, de Lannes ST, Meireles NFT, Viana IS, Hokamura HK.In this study, the effect of early exercise, age, body weight (BW), and growth on the articular cartilage and subchondral bones of the tarsocrural joints was evaluated in 40 young Mangalarga Marchador horses allowed free choice exercise in pasture. Twenty of the horses had additional controlled exercise 3 days per week from a mean age of 30 ± 20 days until 36 months. The training program consisted of an increasing number of 15-minute gallop sprints in an oval paddock with a concrete floor covered by a thick layer of sand. BW, withers height (WH), and neck circumference were measured and bo...
Frazer LL, Santschi EM, Fischer KJ.To predict the bone formation stimulus of a transcondylar screw across an equine subchondral bone cyst (SBC) in an equine medial femoral condyle (MFC). Methods: Finite element modeling (FEM) of an equine MFC with a 2 cm SBC under several transcondylar screw conditions. Methods: The right stifle of a yearling thoroughbred without stifle disease that had been euthanized for reasons unrelated to this study and donated to the University. Methods: The FEM was derived from computed tomography of a yearling thoroughbred and analyzed in ABAQUS v6.14. The transcondylar screw was modeled as a 4.5-mm s...
Balducci JJ, Barrett MF, Moorman VJ.Subchondral or osseous cyst-like lesions within the distal aspect of the middle phalanx are not commonly reported in equids. These osseous lesions, which can communicate with the distal interphalangeal joint, can result in significant lameness and may not respond well to medical management. This report describes the clinical, diagnostic imaging, and surgical management of a 4-year-old mixed breed gelding where medical management of a chronic subchondral osseous cyst-like lesion of the middle phalanx, which communicated with the distal interphalangeal joint, was unsuccessful. A successful outco...
Pawlikowska-Warych M, Deptuła W.One of the most common reasons for horse lameness is subchondral bone cysts (SBCs), which are especially evident in young horse athletes. It is believed that SBC development is strongly associated with an individual's bone growth and/or bone microstructure impairment. Current methods of SBC treatment include pharmacological treatment or surgical procedures which may allow the bone within the cyst to rebuild and be restored to properly developed bone tissue. Thus, we propose filling the SBCs with a 3D complex of alginate hydrogel and autologous adipose derived mesenchymal stem cells (ASCs). We ...
Walmsley EA, Jackson M, Wells-Smith L, Whitton RC.Subchondral bone injury at the palmar/plantar aspect of the condyles of the third metacarpal/metatarsal bone (MC/MT3) commonly causes lameness and poor performance in racehorses. Injury occurs due to repetitive loading, the magnitude of which may be influenced by the position of the distal phalanx relative to the ground surface, i.e. the solar angle. The association of solar angle and injury at the palmar/plantar condyles of distal MC/MT3 therefore warrants investigation. Objective: Investigate the relationship between solar angle and radiopharmaceutical uptake at the palmar/plantar aspect of ...
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...
Cantley CE, Firth EC, Delahunt JW, Pfeiffer DU, Thompson KG.This study identified changes consistent with osteoarthritis; articular cartilage damage, subchondral bone sclerosis and marginal osteophytes, in the metacarpophalangeal joints of wild New Zealand horses. The articular cartilage lesions were identified by Indian ink staining techniques and histology. The lesions occurred on the proximodorsal aspect of the first phalanx (P1) and were more severe on the medial compared to the lateral eminence of the bone, and their severity increased with age. The bone mineral density of the subchondral bone underlying the cartilage lesions, assessed using conve...
Kawcak CE, Frisbie DD, McIlwraith CW.To evaluate effects of extracorporeal shock wave therapy (ESWT) and polysulfated glycosaminoglycan treatment (PSGAGT) on subchondral bone (SCB), serum biomarkers, and synovial fluid biomarkers in horses with induced osteoarthritis. Methods: 24 healthy 2- to 3-year-old horses. Methods: An osteochondral fragment was created on the distal aspect of the radial carpal bone in 1 middle carpal joint of each horse. Horses were randomly allocated to receive local application of ESWT (days 14 and 28; n = 8), PSGAGT (IM, q 4 d for 28 days; 8), or a sham ESWT probe (placebo; days 14 and 28; 8). Serum biom...
Zanotto GM, Liesbeny P, Barrett M, Zlotnick H, Frank E, Grodzinsky AJ, Frisbie DD.Microfracture augmentation can be a cost-effective single-step alternative to current cartilage repair techniques. Trypsin pretreatment combined with a growth factor-functionalized self-assembling KLD hydrogel ("functionalized hydrogel") has been shown to improve overall cartilage repair and integration to surrounding tissue in small animal models of osteochondral defects. Microfracture combined with trypsin treatment and a functionalized hydrogel will improve reparative tissue quality and integration as compared with microfracture alone in an equine model. Controlled laboratory study. Bilater...
Norrdin RW, Stover SM.Mechanical overload leads to a common arthrosis in the metacarpal condyle of the fetlock joint of racehorses. This is usually asymptomatic but severe forms can cause lameness. Subchondral bone failure is often present and the predictability of the site provided an opportunity to study of the progression of bone failure from microcracks to actual collapse of subchondral bone. Twenty-five fetlock condyles from racehorses with various stages of disease were selected. Stages ranged from mild through severe subchondral bone sclerosis, to the collapse of bone and indentation or loss of cartilage kno...
Murray RC, Branch MV, Tranquille C, Woods S.To validate use of magnetic resonance images (MRIs) for measurement of equine articular cartilage and subchondral bone thickness by comparison with measurements in histologic specimens. Methods: 32 cadaveric carpal joints from 16 horses. Methods: Magnetic resonance imaging was performed by use of 3-dimensional fast spoiled gradient echo (SPGR) and T2* 3-dimensional fast gradient echo (GRE) pulse sequences with and without fat saturation. Standard sites on the medial and lateral facets of the intermediate, radial, and third carpal bones were used for subchondral bone and articular cartilage thi...
van de Lest CH, Brama PA, van El B, DeGroot J, van Weeren PR.Osteochondrosis (OC) is the most important developmental orthopaedic disease in the horse. Despite some decades of research, much of the pathogenesis of the disorder remains obscure. Increasing knowledge of articular cartilage development in juvenile animals led to the presumption that the role of collagen in OC might be more important than previously thought. To study collagen characteristics of both cartilage and subchondral bone in young (5 and 11 months of age) horses, samples were taken of subchondral bone and articular cartilage from a group of 43 Dutch Warmblood foals and yearlings that...
Bundgaard L, Åhrman E, Malmström J, Auf dem Keller U, Walters M, Jacobsen S.The objectives of this study was to establish a sensitive and reproducible method to map the cartilage and subchondral bone proteomes in quantitative terms, and mine the proteomes for proteins of particular interest in the pathogenesis of osteoarthritis (OA). The horse was used as a model animal. Protein was extracted from articular cartilage and subchondral bone samples from three horses in triplicate by pressure cycling technology or ultrasonication. Digested proteins were analysed by data independent acquisition based mass spectrometry. Data was processed using a pre-established spectral li...
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...
Backstrom KC, Bertone AL, Wisner ER, Weisbrode SE.To determine whether human parathyroid hormone (hPTH) gene in collagen matrix could safely promote bone formation in diaphyseal or subchondral bones of horses. Methods: 8 clinically normal adult horses. Methods: Amount, rate, and quality of bone healing for 13 weeks were determined by use of radiography, quantitative computed tomography, and histomorphometric analysis. Diaphyseal cortex and subchondral bone defects of metacarpi were filled with hPTH(1-34) gene-activated matrix (GAM) or remained untreated. Joints were assessed on the basis of circumference, synovial fluid analysis, pain on flex...
Johnston GCA, Ahern BJ, Palmieri C, Young AC.(1) Background: Parasagittal groove (PSG) changes are often present on advanced imaging of racing Thoroughbred fetlocks and have been suggested to indicate increased fracture risk. Currently, there is limited evidence differentiating the imaging appearance of prodromal changes in horses at risk of fracture from horses with normal adaptive modelling in response to galloping. This study aims to investigate imaging and gross PSG findings in racing Thoroughbreds and the comparative utility of different imaging modalities to detect PSG changes. (2) Methods: Cadaver limbs were collected from twenty ...
Relave F, Meulyzer M, Alexander K, Beauchamp G, Marcoux M.Lesions located on the medial malleolus of the tarsocrural joint can be difficult to image radiographically. Ultrasonography allows evaluation of articular cartilage and subchondral bone. Objective: To compare dorso30 degrees lateral-plantaromedial-oblique (DL-PIMO) and dorso45 degrees views to detect lesions on the medial malleolus, to validate the use of ultrasonography to show lesions in the tarsocrural joint and to compare its sensitivity to radiography. Methods: Tarsocrural joints (n=111) with osteochondrosis were evaluated ultrasonographically and radiographically prior to arthroscopic l...
Ortved KF, Nixon AJ, Mohammed HO, Fortier LA.To evaluate the long-term clinical outcome after allogeneic chondrocyte and insulin-like growth factor-I (IGF-I) grafting of subchondral cystic lesions (SCLs) of the femoral condyle in horses. Objective: To test the hypothesis that chondrocyte and IGF-I grafts will improve the long-term clinical outcome in arthroscopically debrided SCLs. Methods: Medical records of 49 horses with SCLs of the femoral condyle treated by debridement and implantation of chondrocytes and IGF-I were reviewed. Preoperative radiographs were obtained, and caudocranial radiographic projections were used to establish a r...
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...
von Rechenberg B, Guenther H, McIlwraith CW, Leutenegger C, Frisbie DD, Akens MK, Auer JA.To define the release of nitric oxide (NO), prostaglandin E2 (PGE2), and the neutral metalloproteinases (NMPs) in horses with subchondral cystic lesions (SCL) and to study bone resorption triggered by conditioned media of fibrous tissue of SCL in vitro. Methods: Equine explant cultures of fibrous tissue of SCL, and synovial membrane and articular cartilage of normal horses and horses affected with moderate and severe osteoarthritis were performed. NO, PGE2, and NMP concentrations of media samples were measured, and osteoclast formation and activation was studied in vitro. Methods: Experiment 1...
Rubio-Martínez LM, Cruz AM, Gordon K, Hurtig MB.To characterize the mechanical properties of subchondral bone (SCB) of the distopalmar aspect of the condyles of the third metacarpal bone (MC3) and their correlations with structural aspects of MC3s in Thoroughbred racehorses. Methods: 12 pairs of MC3s from Thoroughbred racehorses euthanized for various reasons. Methods: MC3s were collected from horses with mild (n = 6) and with severe (6) SCB changes, as determined by micro-computed tomography (CT). Specimens of SCB plate and trabecular bone were cut from the distopalmar aspect of condyles and sagittal ridge and examined with 3-dimensional m...
Arkill KP, Winlove CP.Articular cartilage extracellular matrix imposes a significant transport barrier to albumin, the principal carrier of fatty acids. It has not been previously established whether it also influences the transport of fatty acids important for chondrocyte metabolism. Albumin was labelled with rhodamine-maleimide and bound to NBD-labelled lauric acid. Plugs of fresh equine metacarpal-phalangeal cartilage and subchondral bone were incubated with the complex at 4 degrees C for 2-160 h. The fluorophore distribution was quantified using quantitative microscopy in histological sections. The fluorescence...
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...
Lipreri G, Bladon BM, Giorio ME, Singer ER.To compare the outcome following conservative vs surgical management of sports horses with a diagnosis of subchondral bone trauma of the proximal aspect of the proximal phalanx (PP) by low-field MRI. Methods: Retrospective case series. Methods: Twenty-one mature sports horses with evidence of high water signal within the proximal sagittal groove of the PP according to low-field MRI of the fetlock, with no definitive radiographic evidence of fracture. Methods: Medical records (2010-2017) of horses admitted to 2 referral hospitals were reviewed. Historical, clinical, radiographic, and MRI findin...
Mirams M, Tatarczuch L, Ahmed YA, Pagel CN, Jeffcott LB, Davies HM, Mackie EJ.Osteochondrosis is a condition involving defective endochondral ossification and retention of cartilage in subchondral bone. The pathophysiology of this condition is poorly characterized, but it has been proposed that the fundamental defect is failure of chondrocyte hypertrophy. The aim of the current study was to characterize phenotypic changes in chondrocytes associated with the initiation of osteochondrosis. Early lesions were induced in an equine model of osteochondrosis by feeding foals a high energy diet for 8 or 15 weeks. Lesions in articular-epiphyseal growth cartilage were examined hi...
Lin ST, Foote AK, Bolas NM, Peter VG, Pokora R, Patrick H, Sargan DR, Murray RC.Fissure in the third metacarpal/tarsal parasagittal groove and proximal phalanx sagittal groove is a potential prodromal pathology of fracture; therefore, early identification and characterisation of fissures using non-invasive imaging could be of clinical value. Thirty-three equine cadaver limbs underwent standing cone-beam (CB) computed tomography (CT), fan-beam (FB) CT, low-field magnetic resonance imaging (MRI), and macro/histo-pathological examination. Imaging diagnoses of fissures were compared to microscopic examination. Imaging features of fissures were described. Histopathological fin...
Shaffer SK, To C, Garcia TC, Fyhrie DP, Uzal FA, Stover SM.Proximal sesamoid bone (PSB) fracture is the most common fatal injury in Thoroughbred (TB) racehorses in the United States. Epidemiological and pathological evidence indicates PSB fracture is likely the acute culmination of a chronic stress-related process. However, the aetiopathogenesis of PSB fracture is poorly understood. Objective: To characterise bone abnormalities that precede PSB fracture. Methods: Two retrospective case-control groups of PSBs from TB racehorses with, and without, unilateral biaxial PSB fracture. Methods: Proximal sesamoid bones were harvested post-mortem from TB raceho...
Loughridge AB, Hess AM, Parkin TD, Kawcak CE.Changes in subchondral bone density, induced by the repetitive cyclical loading of exercise, may potentiate fatigue damage and the risk of fracture. Objective: To use computed tomography (CT) to characterise bone density patterns at the articular surface of the third metacarpal bone in racehorses with and without lateral condylar fractures. Methods: Case control METHODS: Computed tomographic images of the distal articulating surface of the third metacarpal bone were obtained from Thoroughbred racehorses subjected to euthanasia in the UK. Third metacarpal bones were divided into 3 groups based ...
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...
Martig S, Hitchens PL, Stevenson MA, Whitton RC.The repetitive large loads generated during high-speed training and racing commonly cause subchondral bone injuries in the metacarpal condyles of racehorses. Adaptive bone modelling leads to focal sclerosis at the site of highest loading in the palmar aspect of the metacarpal condyles. Information on whether and how adaptive modelling of subchondral bone changes during the career of a racehorse is sparse. The aim of this cross-sectional study was to describe the changes in subchondral bone micromorphology in the area of highest loading in the palmar aspect of the metacarpal condyle in thorough...
Curtiss AL, Ortved KF, Dallap-Schaer B, Gouzeev S, Stefanovski D, Richardson DW, Wulster KB.Subchondral bone pathology is common in Thoroughbred racehorses and believed to precede more serious injury. Early identification of pathology is critical to allow for intervention. Objective: To determine interobserver variability of fetlock subchondral bone lesions using cone beam and fan beam computed tomography (CBCT, FBCT) and to validate a robotics-controlled CBCT to identify fetlock subchondral bone pathology in the Thoroughbred racehorse. Methods: Prospective cohort study. Methods: FBCT and CBCT images were acquired of 25 metacarpo-/metatarsophalangeal joints of Thoroughbred racehorses...
Martig S, Hitchens PL, Lee PVS, Whitton RC.Subchondral bone injuries often precede articular cartilage damage in osteoarthritis and are common in thoroughbred racehorses due to the accumulation of fatigue damage from high speed racing and training. Thus, racehorses provide a model to investigate the role of subchondral bone in joint disease. We assessed the association of horse and racing related factors and micro-CT based micromorphology of three separate subchondral bone layers with the initial stiffness and compressive fatigue life of bone plugs. Furthermore, we investigated three different definitions of fatigue failure of subchond...
Noble P, Singer ER, Jeffery NS.Sagittal fractures of the first phalanx are a common, potentially catastrophic injury in racehorses. These fractures are often linked to an acute, one time, biomechanical event; however, recent evidence implies that chronic exposure to stress can lead to the accumulation of bony changes that affect the structural integrity of the bone and increase the likelihood of fracture. The aim of the study was to compare variations of two common metrics of bone adaptation - subchondral bone density and thickness across the proximal articular surface of the first phalanx in Thoroughbred horses that (1) ra...
Ammann L, Ohlerth S, Fürst AE, Jackson MA.To determine morphological characteristics of subchondral cystic lesions (SCLs) in the proximal phalanx (PP) of adult horses. Methods: Radiographs and/or CT scans of PP from 46 horses. Methods: There were horses with a SCL in PP, which was diagnosed by radiography and/or computed tomography, included. Additional data (signalment, history, orthopedic examination) were collected retrospectively for each case. Results: Forty-six horses met the required inclusion criteria, with a total of 62 SCLs. Forty-three SCLs (70.5%) were located in the proximal PP (group A). Forty-four percent of these were ...
Zubrod CJ, Schneider RK, Tucker RL, Gavin PR, Ragle CA, Farnsworth KD.To assess the use of magnetic resonance (MR) imaging for identifying subchondral bone damage in the distal limbs of horses. Methods: Retrospective study. Methods: 11 horses. Methods: Medical records of horses with lameness and subsequent evidence of subchondral bone damage as determined by MR imaging were reviewed. Severity and duration of lameness, results of diagnostic local anesthesia and diagnostic testing, surgical and necropsy findings, and treatment were recorded. Outcome was determined by follow-up information obtained from the owner or referring veterinarian. Results: Lameness was loc...
