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.
Gustås P, Johnston C, Roepstorff L, Drevemo S, Lanshammar H.The transmission of shockwaves following hoof impact is proposed to be one major source of stress to the limb. In the forelimb, there are indications that the period of horizontal deceleration of the hoof is related to the attenuation of shockwaves. In the hindlimb, information about the hoof deceleration has been lacking. Objective: To compare hoof deceleration patterns between the fore- and hindlimbs. Methods: Seven Standardbreds were trotted by hand over a force plate covered with sand, with triaxial accelerometers mounted on the fore and hind hooves. Variables representative of deceleratio...
Ekman S, Skiöldebrand E, Heinegård D, Hultenby K.One of the most common causes of lameness in racehorses is osteoarthritis (OA). Pathogenesis is not clear and pathological processes of the different joint tissues interact in often progressive events. The interface between cartilage and newly synthesised bone has been shown to be particularly enriched in bone sialoprotein (BSP), a cell-binding matrix protein. Objective: To establish whether changes in the concentration of BSP may serve as a marker for early biochemical changes of the subchondral bone. Methods: Articular cartilage, cartilage/bone interface and subchondral bone of the proximal ...
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...
García-López JM, Kirker-Head CA.To report the clinical signs, diagnosis, management, and outcome of horses with occult sub-chondral osseous cyst-like lesions of the tarsocrural joint. Methods: Retrospective study. Methods: Twelve horses with subchondral osseous cyst-like lesions (SOCLs) in the tarsocrural joint. Methods: Information about history, examination findings, diagnostic techniques, and surgical procedures as obtained from medical records. Outcome was determined by patient re-evaluation and telephone communication with the referring veterinarian, owner, or trainer. Results: Horses were aged from 3 to 29 years. Lamen...
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...
van der Harst MR, Brama PA, van de Lest CH, Kiers GH, DeGroot J, van Weeren PR.In articular joints, the forces generated by locomotion are absorbed by the whole of cartilage, subchondral bone and underlying trabecular bone. The objective of this study is to test the hypothesis that regional differences in joint loading are related to clear and interrelated differences in the composition of the extracellular matrix (ECM) of all three weight-bearing constituents. Methods: Cartilage, subchondral- and trabecular bone samples from two differently loaded sites (site 1, dorsal joint margin; site 2, central area) of the proximal articular surface of 30 macroscopically normal equ...
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...
Scott GS, Crawford WH, Colahan PT.To determine arthroscopic findings in lame horses with subtle radiographic lesions of the medial femoral condyle. Methods: Retrospective study. Methods: 15 horses examined because of lameness that had subtle radiographic evidence of osteochondral lesions involving the medial femoral condyle in at least 1 joint. Methods: Medical records were reviewed, and results of physical examination, radiography, and arthroscopy were recorded. Follow-up information was obtained through reexamination of the horses or telephone conversations with the referring veterinarians, owners, or trainers. Results: Lame...
Story MR, Bramlage LR.Historically, there has been a consensus that conservative management of subchondral cystic lesions of the distal phalanx carries a poor prognosis. Surgical management has been advocated; however, there are no reports documenting its routine use and successful surgical treatment. Objective: To describe arthroscopically-guided curettage of distal phalangeal subchondral cystic lesions (SCLs) and report the qualitative and quantitative results in 11 affected horses age 16-33 months. Methods: Medical records of horses with previously treated lameness resulting from SCLs of the third phalanx were r...
Walker JE, Lewis CW, MacLeay JM, Kawcak CE, Wheeler DL.Functional relationships between articular cartilage and underlying subchondral bone have been shown to be associated with the progression of osteoarthritis (OA). However, quantifiable factors substantiating this relationship do not exist. Therefore, the study objective involved quantifying subchondral bone mineral density (BMD) of the equine metacarpophalangeal (MCP) and stifle joints as a step in determining if regional subchondral BMD may be associated with OA changes. BMD was bilaterally quantified using dual energy xray absorptiometry (DEXA) for four subchondral regions: palmer and dorsal...
Harmel JL, Lewis CW, Sah RL, Kawcak CE, Wheeler DL.Millions of Americans suffer from osteoarthritis, a joint disease characterized by cartilage degradation and subchondral bone sclerosis. However, little is known about its pathology. It remains to be discovered which comes first in the progression of osteoarthritis: subchondral bone remodeling or cartilage degeneration. This study assessed equine cartilage degeneration, based upon measurements of cartilage thickness and Indian ink stain uptake. By gaining a greater understanding of the determining factors in cartilage degeneration, we may be able to better understand the pathomechanics of oste...
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...
Björnsdóttir S, Ekman S, Eksell P, Lord P.Osteoarthrosis (OA) in the distal tarsal joints, bone spavin, is a well known condition which is common in Icelandic horses age 6-12 years. Objective: To determine the nature, location and age of appearance of early radiographic and histological changes in the centrodistal tarsal joint (CD) of young Icelandic horses. Methods: Slab sections from the CD of young Icelandic horses were examined by high detail radiography (age 6 months to 6 years, n = 111) and histology (age 6 months to 4 years, n = 82) to detect and describe the early changes indicative of OA. Horses younger than 5 years were unri...
Semevolos SA, Nixon AJ, Strassheim ML.To determine the mRNA expression of bone morphogenetic protein (BMP)-6 and -2 and a BMP antagonist (Noggin) in horses with osteochondrosis. Methods: Samples of articular cartilage from affected stifle or shoulder joints of 10 immature horses with naturally acquired osteochondrosis and corresponding joints of 9 clinically normal horses of similar age; additionally, samples of distal femoral growth plate cartilage and distal femoral articular cartilage were obtained from a normal equine fetus. Methods: Cartilage specimens were snap-frozen in liquid nitrogen, and total RNA was isolated. Adjacent ...
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...
Frisbie DD, Oxford JT, Southwood L, Trotter GW, Rodkey WG, Steadman JR, Goodnight JL, McIlwraith CW.The current study investigated healing of large full-thickness articular cartilage defects during the first 8 weeks with and without penetration of the subchondral bone using microfracture in an established equine model of cartilage healing. Chondral defects in the weightbearing portion of the medial femoral condyle were made bilaterally; one defect in each horse was microfractured whereas the contralateral leg served as the control. The expression of cartilage extracellular matrix components (Types I and II collagen and aggrecan) was evaluated using histologic techniques, reverse transcriptio...
Dyson S, Murray R, Schramme M, Branch M.Foot pain is a common cause of equine lameness and there have been significant limitations of the methods available for the diagnosis of the causes of foot pain (radiography, nuclear scintigraphy and ultrasonography). Until recently, magnetic resonance imaging (MRI) in the horse has been limited to examination of cadaver limbs. Objective: Our purpose was to 1) describe MRI of the foot in live horses, 2) describe MRI findings in horses with foot pain in which a definitive diagnosis could not be established by alternative means and 3) correlate MRI findings with other methods of clinical investi...
Schoenborn WC, Rick MC, Hornof WJ.A 6-year-old Thoroughbred gelding presented with a left forelimb lameness. The results of lameness examination, radiography, nuclear scintigraphy, and computed tomography are presented. Based on the diagnostic imaging, subchondral fractures and osteochondritis dissecans lesions of the proximal articular surface of the proximal phalanx were diagnosed. A brief discussion of osteochondritis dissecans is presented.
van de Lest CH, Brama PA, van Weeren PR.This study aimed at the determination of the influence of exercise on the levels of a number of bone morphogenic enzymes in subchondral bone and at the comparison of these data with other (subchondral) bone-related parameters that have been investigated in the same experimental population.Forty-three foals were reared until weaning at 5 months of age under similar conditions, except for the type and amount of exercise. Fifteen foals remained at pasture (Pasture group and also control group), 14 foals were kept in box stalls (Box group) and 14 foals were kept in the same box stalls but were sub...
Peroni JF, Stick JA.To describe a single-portal cranial arthroscopic approach to the stifle joint in horses and to determine the clinical outcome in horses with femorotibial joint disease in which this approach was used. Methods: Retrospective study. Methods: 23 adult horses. Methods: Medical records were reviewed to obtain information on clinical outcome in horses in which the single-portal cranial arthroscopic approach was used. Results: Twenty-nine stifle joints of 23 horses were examined arthroscopically, using the described approach. Subchondral bone cysts were treated in 19 medial femoral condyles of 12 hor...
Murray RC, Znaor N, Tanner KE, DeBowes RM, Gaughan EM, Goodship AE.Dorsal carpal osteochondral injury is a major cause of lameness in horses undergoing high intensity training. Intra-articular corticosteroid treatment is used commonly to manage exercise-associated articular pain, but its use remains highly controversial in the equine athlete. This project, therefore, aimed to compare the mechanical properties of intra-articular MPA and diluent-treated middle carpal subchondral and cancellous bone in horses undergoing a short-term treadmill exercise programme. It was hypothesised that subchondral and cancellous bone mechanical properties are influenced by intr...
van de Lest CH, Brama PA, Van Weeren PR.An overview is given of the direct and long-term effects of exercise on the biochemical characteristics of cartilage and subchondral bone, and on the metabolic activity of chondrocytes in the juvenile horse. In the experimental setup 43 foals were reared until weaning at 5 months of age under similar conditions, except for the type and amount of exercise. Fifteen foals remained at pasture (Pasture group and also control group), 14 foals were kept in box stalls (Box group), and 14 foals were kept in the same box stalls but were subjected daily to an increasing number of gallop sprints (Training...
Brama PA, TeKoppele JM, Bank RA, Barneveld A, 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 and the mineral content. In the present study, part of the normal developmental process and the influence of physical activity on biochemical composition of subchondral bone was studied. Water content, calcium content and characteristics of the collagen network (collagen, hydroxylysine, lysylpyridinoline (LP) and hydroxylysylpyridinoline (HP)...
van Harreveld PD, Lillich JD, Kawcak CE, Turner AS, Norrdin RW.To determine microradiographic appearance, bone histomorphometry, and mineral density of the long bones of the metacarpophalangeal joint in horses after immobilization followed by remobilization. Methods: 5 healthy horses. Methods: One forelimb of each horse was immobilized in a fiberglass cast for 7 weeks, followed by 8 weeks of increasing exercise. Calcein and oxytetracycline were administered IV during the immobilization and exercise phases, respectively, for bone labeling and analysis after euthanasia. Sagittal sections of metacarpal bones and proximal phalanges were examined via radiograp...
Murray RC, Vedi S, Birch HL, Lakhani KH, Goodship AE.It was hypothesised that subchondral bone thickness, hardness and remodelling are influenced by exercise intensity, and by location within a joint. Dorsal carpal osteochondral injury is a major cause of lameness in horses undergoing high intensity training. This project aimed to determine the subchondral bone thickness, formation, resorption and hardness at sites with high and low incidence of pathology in 2 year-old horses undergoing 19 weeks high intensity treadmill training or low intensity exercise, and to compare these factors between exercise groups. Dorsal and palmar test sites were ide...
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...
von Rechenberg B, Leutenegger C, Zlinsky K, McIlwraith CW, Akens MK, Auer JA.This study investigated the potential association of interleukin-1beta (IL-1beta) and interleukin-6 (IL-6) in subchondral cystic lesions (SCL) in horses. With the technique of in situ hybridisation in paraffin sections of fibrous tissue of SCL and quantitative real-time PCR in fresh frozen fibrous tissue and undecalcified bone sections of SCL embedded in acrylic resin, upregulation of mRNA of both cytokines could be demonstrated. mRNA of IL-1beta was upregulated at the periphery of the cystic lesion adjacent to normal bone, whereas IL-6 mRNA was upregulated within the fibrous tissue found with...
Kawcak CE, McIlwraith CW, Norrdin RW, Park RD, James SP.Subchondral bone plays a role in the pathogenesis of osteochondral damage and osteoarthritis in horses and humans. Osteochondral fragmentation and fracture, subchondral bone necrosis and osteoarthritis are common diseases in athletic horses, and subchondral bone is now thought to play an integral role in the pathogenesis of these diseases. There have been numerous research efforts focused on articular cartilage damage and its pathogenesis, yet comparatively little effort focused on subchondral bone pathology or the coordinated disease states of the osteochondral tissues. The purpose of this re...
Textor JA, Nixon AJ, Lumsden J, Ducharme NG.To determine clinical and radiographic features of subchondral cystic lesions (SCL) of the proximal extremity of the tibia in horses that could be used to classify these lesions as being related to osteochondrosis or osteoarthritis and to evaluate results of surgical debridement. Methods: Retrospective study. Methods: 12 horses with 14 SCL. Methods: Medical records and radiographs obtained before and after treatment were reviewed. Results: In 6 young horses (8 lesions), SCL were considered to be related to osteochondrosis; all involved the lateral tibial condyle. The remaining 6 horses were ma...
Doyle PS, White NA.To determine clinical, scintigraphic, radiographic, and arthroscopic findings and results of treatment in horses with lameness attributable to subtle osteochondral lesions of the shoulder joint. Methods: Retrospective study. Methods: 15 horses. Methods: Medical records were reviewed, and results of physical examination, scintigraphy, radiography, arthroscopy, and treatment were recorded. Results: Severity of lameness ranged from grade 1 to 4. Response to shoulder flexion or extension was variable. Twelve horses had a narrow upright foot. Intra-articular anesthesia of the shoulder joint localiz...
Goodrich LR, McIlwraith CW, Grieger J, Kraus VB, Stabler T, Werpy N, Phillips J, Samulski RJ, Frisbie D.To evaluate the effects of a gene transfer approach to IL-1β inhibition in an equine osteochondral chip fragment model of joint injury using a self-complementary adeno-associated virus with interleukin receptor antagonist transgene cassette (scAAVIL-1ra), as posttraumatic osteoarthritis in horses, similar to people, is a significant clinical problem. Methods: 16 horses were utilized for the study. Methods: All horses had an osteochondral chip fragment induced arthroscopically in one middle carpal joint while the contralateral joint was sham operated. Eight horses received either scAAVIL-1ra o...
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...
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...
van de Lest CH, Brama PA, van Weeren PR.This study aimed at the determination of the influence of exercise on the levels of a number of bone morphogenic enzymes in subchondral bone and at the comparison of these data with other (subchondral) bone-related parameters that have been investigated in the same experimental population.Forty-three foals were reared until weaning at 5 months of age under similar conditions, except for the type and amount of exercise. Fifteen foals remained at pasture (Pasture group and also control group), 14 foals were kept in box stalls (Box group) and 14 foals were kept in the same box stalls but were sub...
Kold SE, Hickman J.The results of surgical treatment of 10 subchondral bone cysts, all located in the medial femoral condyle, are presented. A cancellous bone graft was used in nine cases and a two component acrylic bone cement was used in the case of an extremely large cyst. Eight out of the 10 cases made a satisfactory clinical recovery.
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 ...
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...
Walker JE, Lewis CW, MacLeay JM, Kawcak CE, Wheeler DL.Functional relationships between articular cartilage and underlying subchondral bone have been shown to be associated with the progression of osteoarthritis (OA). However, quantifiable factors substantiating this relationship do not exist. Therefore, the study objective involved quantifying subchondral bone mineral density (BMD) of the equine metacarpophalangeal (MCP) and stifle joints as a step in determining if regional subchondral BMD may be associated with OA changes. BMD was bilaterally quantified using dual energy xray absorptiometry (DEXA) for four subchondral regions: palmer and dorsal...
Jeffcott LB, Kold SE, Melsen F.The gross and histological appearance of subchondral bone cysts in six Thoroughbred or partbred horses is described. The lesions were all situated in the centre of the medial femoral condyle and were not associated with any other damage to the articular surface of the femorotibial or femoropatellar joints. In three cases the cysts were unilateral but had an early non-cystic lesion present in the opposite stifle. All the cysts had a narrow channel at their distal extremity which communicated with the femorotibial joint. The more recently developed ones were fluid filled and contained fibrous st...
Scott EA, Snyder SP, Schmotzer WB, Pool R.Probable cause of fracture in a Paint gelding was a congenital bone defect involving the extensor process area of the right and left forelimb distal phalanges. Radiographically and histologically, subchondral bone cysts at the fracture lines were suspected. These cysts were thought to have developed in association with abnormal ossification centers at the extensor process areas of the third phalanx. Partial avulsion of weak extensor processes would then occur from natural forces exerted on these weakened bony prominences via the common digital extensor tendon. Support for osteochondrosis as a ...
Whitton RC, Murray RC, Buckley C, Goodship AE, Lekeux P.Training results in marked modelling of the subchondral bone of the carpus, but the effect of training on the subchondral bone of the distal tarsal joints is unknown. The aim of this study was to determine whether training influenced modelling of the third and central tarsal bones in Thoroughbred horses. Twelve untrained Thoroughbred horses were divided into 2 groups. Group 1 underwent a 19 week progressive training regimen on a high speed treadmill. Group 2 were walked for 40 min daily. Images of left tarsi were obtained by magnetic resonance imaging (MRI) with a 0.5 Tesla superconducting mag...
Anne-Archard N, Martel G, Fogarty U, Richard H, Beauchamp G, Laverty S.The aetiology of equine metacarpal condylar fractures is not completely understood and a developmental cause has been postulated. Objective: To investigate the subchondral bone trabecular microarchitecture of the lateral parasagittal groove and condyle in equine neonates and its adaptation with maturation and athletic activity. Methods: Ex vivo observational study. Methods: Distal metacarpi of neonates, yearlings and adult racehorses (n = 24) were harvested. Dorsal and palmar frontal histological sections, containing the lateral parasagittal groove and condyle, were studied. The sections were ...
Semevolos SA, Nixon AJ, Strassheim ML.To determine the mRNA expression of bone morphogenetic protein (BMP)-6 and -2 and a BMP antagonist (Noggin) in horses with osteochondrosis. Methods: Samples of articular cartilage from affected stifle or shoulder joints of 10 immature horses with naturally acquired osteochondrosis and corresponding joints of 9 clinically normal horses of similar age; additionally, samples of distal femoral growth plate cartilage and distal femoral articular cartilage were obtained from a normal equine fetus. Methods: Cartilage specimens were snap-frozen in liquid nitrogen, and total RNA was isolated. Adjacent ...
Textor JA, Nixon AJ, Lumsden J, Ducharme NG.To determine clinical and radiographic features of subchondral cystic lesions (SCL) of the proximal extremity of the tibia in horses that could be used to classify these lesions as being related to osteochondrosis or osteoarthritis and to evaluate results of surgical debridement. Methods: Retrospective study. Methods: 12 horses with 14 SCL. Methods: Medical records and radiographs obtained before and after treatment were reviewed. Results: In 6 young horses (8 lesions), SCL were considered to be related to osteochondrosis; all involved the lateral tibial condyle. The remaining 6 horses were ma...
Pullin JG, Collier MA, Das P, Smith RL, DeBault LE, Johnson LL, Walls RC.Comparison of perilesional cartilage, lesional repair tissue, and subchondral bone activity 6 months after application of holmium-yttrium-aluminum-garnet (Ho:YAG) laser energy to chronic (10 week) induced 10-mm full-thickness (FT) circular articular cartilage craters followed by 6 months' intermittent active motion (IAM) in a free exercise environment was investigated. The 2.1-microns wavelength was delivered in hand-controlled near-contact mode by arthroscopic surgery in a saline medium. Bilateral arthroscopy was performed on normal antebrachiocarpal, intercarpal, and metacarpophalangeal join...
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...
Uhlhorn H, Ekman S, Haglund A, Carlsten J.Thirty-five carpal joints from 20 standardbred trotters, age 1 to 7 years, all euthanized for nonorthopedic reasons, were examined to investigate the correlation between assessments of subchondral bone sclerosis in the third carpal bone from radiographs in the dorsoproximal-dorsodistal (DPr-DDi) projection and histomorphometric bone volume density measurements. The agreement between assessments of sclerosis from antemortem versus postmortem radiographs was also evaluated. Bones graded as sclerotic in the DPr-DDi projection had significantly higher bone volume density values for all areas of me...
Kobrina Y, Isaksson H, Sinisaari M, Rieppo L, Brama PA, van Weeren R, Helminen HJ, Jurvelin JS, Saarakkala S.The collagen phase in bone is known to undergo major changes during growth and maturation. The objective of this study is to clarify whether Fourier transform infrared (FTIR) microspectroscopy, coupled with cluster analysis, can detect quantitative and qualitative changes in the collagen matrix of subchondral bone in horses during maturation and growth. Equine subchondral bone samples (n = 29) from the proximal joint surface of the first phalanx are prepared from two sites subjected to different loading conditions. Three age groups are studied: newborn (0 days old), immature (5 to 11 months ol...
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...
Skiöldebrand E, Adepu S, Lützelschwab C, Nyström S, Lindahl A, Abrahamsson-Aurell K, Hansson E.This study aimed to test a novel treatment combination (TC) (equivalent to sildenafil, mepivacaine, and glucose) with disease-modifying properties compared to Celestone® bifas® (CB) in a randomized triple-blinded phase III clinical study in horses with mild osteoarthritis (OA). Joint biomarkers (reflecting the articular cartilage and subchondral bone remodelling) and clinical lameness were used as readouts to evaluate the treatment efficacy. Unassigned: Twenty horses with OA-associated lameness in the carpal joint were included in the study and received either TC (n = 10) or CB (n = ...
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...
Branch MV, Murray RC, Dyson SJ, Goodship AE.Osteoarthritis (OA) is a common cause of distal tarsal pain, but disease development is poorly understood. Awareness of normal tarsal structure and function is important in order to understand the pathogenesis of OA. Thickening of the subchondral bone (SCB) plate has been related to the development of OA, but SCB plate patterns in the equine tarsus have not been documented. Objective: There is a repeatable pattern of SCB thickness across the distal tarsal joints, and specifically that thickness would be greatest dorsally and laterally. Methods: Twenty cadaver tarsi were collected from mature h...
Pál Z, Bodó G.Allograft arthroplasty is a promising cartilage-resurfacing technique. A 14-year-old horse was diagnosed with a medial femoral condyle subchondral bone cyst. Allografts were harvested from a young donor animal and implanted to fill the cyst cavity. A visual assessment of the surgical site was possible during follow-up arthroscopy. In addition to a desirable gliding surface and a good adaptation of the grafts, fibrillation of the cranial ligament of the medial meniscus was noted and debrided. The recipient horse became sound four months after follow-up surgery with a high level of owner satisfa...
Drum MG, Les CM, Park RD, Norrdin RW, McIlwraith CW, Kawcak CE.The purpose of this study was to compare subchondral bone density obtained using quantitative computed tomography with ash density values from intact equine joints, and to determine if there are measurable anatomic variations in mean subchondral bone density. Five adult equine metacarpophalangeal joints were scanned with computed tomography (CT), disarticulated, and four 1-cm(3) regions of interest (ROI) cut from the distal third metacarpal bone. Bone cubes were ashed, and percent mineralization and ash density were recorded. Three-dimensional models were created of the distal third metacarpal...
Riley CB, Yovich JV, Huxtable CR.A fusion defect of the proximal and middle phalanges of both hindlimbs, osteochondrosis dissecans of the distal interphalangeal joints of the forelimbs, and subluxation of all 4 distal interphalangeal joints occurred in a Standardbred filly. Lameness was the first abnormality noted and was observed at one week of age in the left forelimb and progressed until all 4 limbs were affected by 5 weeks of age. On radiographs of both forelimbs, the distal interphalangeal joints were subluxated with irregularity and lucency of subchondral bone. On radiographs of the distal hindlimbs, there was a subluxa...
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 ...
Björnsdóttir S, Ekman S, Eksell P, Lord P.Osteoarthrosis (OA) in the distal tarsal joints, bone spavin, is a well known condition which is common in Icelandic horses age 6-12 years. Objective: To determine the nature, location and age of appearance of early radiographic and histological changes in the centrodistal tarsal joint (CD) of young Icelandic horses. Methods: Slab sections from the CD of young Icelandic horses were examined by high detail radiography (age 6 months to 6 years, n = 111) and histology (age 6 months to 4 years, n = 82) to detect and describe the early changes indicative of OA. Horses younger than 5 years were unri...
Sparks HD, Nixon AJ, Bogenrief DS.3 horses were referred for treatment of subchondral cystic lesions of 1 or both medial femoral condyles. Results: All horses had clinically apparent lameness confirmed to be due to a radiographically evident subchondral cystic lesion of the medial femoral condyle with a large articular component (> 15 mm) and shallow subchondral depth (< 10 mm). Arthroscopic assessment of affected cartilage revealed undulating cartilage with a relatively smooth surface and extensive residual perimeter attachment. Results: Resorbable polydioxanone pins were used arthroscopically to reattach the cartilage ...
