Juvenile Osteochondral Conditions Research Articles

Radiographic prevalence of juvenile osteochondral conditions of the proximal interphalangeal joint of Australian Thoroughbred racehorse yearlings and associations with sales results and race performance.

ObjectivesAscertain the radiographic prevalence and variation in characteristics of juvenile osteochondral conditions (JOC) in the proximal interphalangeal joint (PIPJ) of Australian Thoroughbred racehorse yearlings. Establish whether there are any significant associations with public auction sale results and racing performance.MethodsRetrospective evaluation of 1,098 yearling repository radiograph sets. Comparison of sales results and whole career racing performance of the case group with two control groups: maternal siblings (N = 397) and yearlings without PIP JOC (N = 391).Results6.3% of yearlings had at least one PIPJ JOC lesion with 4.8% having subchondral lucencies of the proximal phalanx (P1SC), 0.6% with subchondral lucencies of the middle phalanx (P2SC) and 0.8% with osteochondral fragmentation (OCF). P1SC were more prevalent in forelimbs and P2SC and OCF were more commonly located in the hindlimbs. 51% of PIPJ JOC were not identified on a lateromedial projection (LM). A significantly lower proportion of horses with OCF were successfully sold at public auction (p ≤ 0.05) but there was no significant difference in sales price between the case group and controls. A lower proportion of horses with PIPJ JOC made it to the racetrack to race, although this was not statistically significant. There was no significant difference in racing performance between the case group and controls, although there was a trend toward case horses earning lower career prize money and lower prize money per race (p ≤ 0.1). Lesions located in a dorsal or palmar/plantar location on the LM projection earned a lower average prize money per race (p ≤ 0.05) than those in a central location, and showed a trend toward earning lower total prize money (p ≤ 0.1) and number of places (p ≤ 0.1). There was no significant difference in performance for horses with lesions at the medial, axial or lateral aspects of the articular surface.Clinical importanceOverall, the findings of this study indicate that the presence of PIPJ JOC in radiographs of Thoroughbred yearlings should be attributed a low to moderate risk to future racing performance, however certain lesion characteristics may be associated with decreased performance.

Prevalence of Juvenile Osteochondral Conditions in Yearling Thoroughbred Racehorses in Southern Brazil

This study aimed to investigate the prevalence of juvenile osteochondral conditions (JOCCs) in yearling Thoroughbred (TB) racehorses in Southern Brazil, as well as to examine the same animals studied as weanlings by Bastos et al. (2017) and compare the radiographic findings for the two ages. Radiographs of 76 male and female TB yearlings from Paraná State, Southern Brazil, were investigated. The proximal interphalangeal, metacarpophalangeal/metatarsophalangeal (MC/MT), tarsal, and femorotibial (FT) joints were evaluated using 24 radiographic projections. The evaluation consisted of a severity index (rated as 0, 1, 2, 4, or 8), the sum of which resulted in an osteoarticular status (OAS) of good, intermediate, or poor for each animal. Radiographs of 92% of the investigated animals presented at least one finding consistent with JOCCs. The most affected region was the tarsal joint (72.9%), followed by the FT (50%), MT (25%), and MC (23%) joints. Thirty-three (43.4%) horses presented a decline in their OAS, whereas nine (11.8%) presented an improvement from the weanling to yearling age. The radiographic findings suggest that JOCCs are frequent in TB yearlings, but the meaning and relevance of these radiographic findings require further study.

Radiological Evaluation of Juvenile osteochondral Conditions in Brazilian Warmblood Horse

The term juvenile osteochondral condition (JOCC) has been used to identify developmental changes in the growth plates. The condition is characterized by a set of changes with similar pathogenesis that affect the immature skeleton and joints of growing foals. The aim of the current study is to investigate the prevalence and degree of severity of osteochondral changes in Brazilian warmblood (BW) foals in two farms in the south of Brazil. Radiological evaluation was applied to the metacarpophalangeal (MCP), carpal (C), metatarsophalangeal (MTP), tarsal (T), and femorotibiopatellar (FTP) joints of 90 foals (47 females and 43 males) in the age group 16–36 months. The evaluation was made before the animals started their athlete performance. Changes were classified as a degree of severity 0 to 4. Changes were diagnosed in 56 foals (58%) that had 105 affected joints. Thirty-three (59%) out of the 56 animals had changes in more than one joint; 57% (19/33) of them had bilateral changes. MTP and MCP were the joints with the most severe changes, respectively (severity 2 and 3), followed by FTP, T, and C. Osteochondral fragments (59%), tarsal arthropathies (48%), irregularities and radiolucency in the FTP joint (7%), and subchondral cystic lesion in the FTP joint (1%), were the most observed changes. BW foals recorded the high prevalence of osteochondral alterations; although MTP and T were the most affected joints, MTP and MCP presented the most severe changes. The present study confirmed significant JOCC prevalence in BW. Further studies should be carried out in different properties.

Incidence of Juvenile Osteochondral Conditions in Thoroughbred Weanlings in the South of Brazil

The goal of this study was to determine the occurrence of juvenile osteochondral conditions (JOCCs) in Brazilian Thoroughbred weanlings from 4 to 6 months of age. Eighty-five foals from four different stud farms were evaluated. The history and husbandry of all animals were obtained by questionnaire, and clinical examination was performed to detect lameness. Radiographic evaluations included 24 radiographic projections from eight different joints (right and left metacarpophalangeal, metatarsophalangeal, tarsocrural, and femorotibial [FT] joints), for a total of 2,040 radiographs. Twenty locations within those joints were examined, and a severity index (SI) was determined for each location. The sum of the SI values for each foal was used to determine the osteoarticular status (OAS), which was classified as good, intermediate, or poor. None of the 85 foals examined had clinical signs of lameness. Sixty-five (76.5%) foals had one or more findings related to JOCC. In total, 680 joints were examined and scored, with 20.7% affected. The FT joints were the most commonly affected (n = 62; 9.1%). There was no significant difference in JOCC occurrence between the left and right limbs. The OAS was considered good in 38.8% (n = 33) of the foals studied, intermediate in 48.2% (n = 41), and poor in 12.9% (n = 11). There were significant differences in OAS among the four stud farms.

Association of growth, feeding practices and exercise conditions with the severity of the osteoarticular status of limbs in French foals

The aim of this study was to identify the risk factors for the severity of Juvenile OsteoChondral Conditions (JOCC) in limbs of French foals. Twenty-one farms in Normandy, France, were sampled and enrolled in a cohort study including 378 foals from three breeds, followed from the 8th month of pregnancy of the mares until the foals were approximately 6months old. Data on growth, feeding practices and exercise conditions were regularly collected. The carpus, the front and hind digits, the hock and the stifle of the foals were radiographed at the end of follow-up. JOCC severity in each foal was described using a global appraisal of its osteoarticular status (OAS) depending on the number and the severity of radiographic findings.Of the 378 foals, 53% had a good OAS, 34% had an intermediate OAS and 13% had a poor OAS. The breed (Selle Français and French Trotter Standardbred vs. Thoroughbred), a high girth perimeter at early age and an irregular exercise were significantly associated with a poor OAS. This study contributes to the understanding of the development of JOCC. An increased growth and reduced or irregular physical activity during the first weeks of life would be responsible for more severe lesions. Growth and exercise conditions should be carefully monitored to reduce the prevalence of severe JOCC in foals.

Evolution of radiological findings detected in the limbs of 321 young horses between the ages of 6 and 18 months

The objective of this study was to evaluate the spontaneous evolution of radiological findings (RF) indicative of juvenile osteochondral conditions (JOCC) in a field study. A radiographic survey was performed at the age of 6 and 18months in 321 young horses from three breeds (French Trotter Standardbred, Selle-Français Warmblood and Thoroughbred). Each RF identified at 6months was re-evaluated at 18months, and classified as (1) disappeared, (2) improved, (3) stable, (4) deteriorated or (5) new when it was not identified at 6months.Only 32.3% of all RF identified at the age of 6months were stable, while at 18months 46.6% had disappeared and 38.7% were new radiological abnormalities. Evolution of RF varied according to the joint involved and the type of lesion. In the stifle, 85.7% of the RF of osteochondral fragmentation (OCF) of the lateral ridge of the femoral trochlea regressed (disappeared or improved). In the hock, 53.1% of the RF of OCD of the intermediate ridge of the tibial cochlea were stable. In the fetlock, dorsal and plantar OCF were frequently observed as new radiological abnormalities at 18months (51% of the dorsal RF and 45.8% of the plantar).As many lesions develop or change after 6months, a definitive radiographic assessment of the JOCC status is more reliable at 18months. Knowing the spontaneous healing capacity of some lesions is useful in helping to decide the appropriate management.

Radiographic findings of juvenile osteochondral conditions detected in 392 foals using a field radiographic protocol

Radiographic examination in young horses is commonly used to detect juvenile osteochondral conditions (JOCC). The aim of this study is to present the radiographic findings (RF) detected at the age of 6months in the joints of 392 foals from three breeds: French Trotter Standardbreds (FT), Selle-Français Warmbloods (SF) and Thoroughbreds (TB). Radiographic examination included lateromedial views of the fore and hind digits, tarsi and stifles, and dorsopalmar projections of both carpi. In all areas RF indicative of JOCC were classified according to a four-grade severity scoring system.Distribution and severity of the RF varied according to breed with the SF most affected. The most frequently affected site was the hind fetlock (28.3% of foals). The second most affected site was the fore fetlock in TB and SF, while the carpus and proximal tarsus were the second and third affected sites in FT. The radiographic protocol and grading system used can serve as a basis for field research and further studies on the evolution of RF, risk factors for JOCC or the correlation between RF and the subsequent athletic career of horses.

Study design for the investigation of likely aetiological factors of juvenile osteochondral conditions (JOCC) in foals and yearlings

The possible aetiology of osteochondrosis and, to a lesser extent, other developmental orthopaedic diseases or juvenile osteochondral conditions (JOCC), has been intensively investigated. However, most studies have focused on single factors of this multi-factorial disorder, or have been conducted under experimental conditions. This paper aims to present and discuss the scientific background of the BOSAC (Breeding, Osteochondral Status and Athletic Career) research program, a multi-factorial investigation on JOCC risk factors in field conditions.The epidemiology of JOCC in horses born in Normandy between 2002 and 2004 was studied. Horses were subjected to repeated body measurements, blood sampling and locomotion evaluation from birth until yearling sales. A radiographic examination, including 10 views of the limbs, was performed on each subject at approximately 6 and 17months of age. Information on nutrition and management programmes was collected by specialists from visits to the farms and the use of questionnaires. A total of 393 foals of three French breeds were monitored from birth to weaning, and 321 of these remained available for further follow-up, making the study unique as regards both the number of subjects and the variety of information collected. The study was designed to describe the evolution of JOCC, and determine possible early markers, risk factors and prognostic factors with respect to performance. Relevant data, suitable for epidemiological analyses, were collected under various field conditions that reflect current management practices in Normandy, France’s main horse breeding region.

Effects of management practices as risk factors for juvenile osteochondral conditions in 259 French yearlings

Several studies have demonstrated a statistical association between management practices and juvenile osteochondral conditions (JOCC) in foals from birth to 6months of age, but this association has not been investigated in yearlings. The purpose of the current study was to determine the adjusted effects of management practices on the onset and evolution of JOCC in French yearlings. The study sample consisted of 259 yearlings born on 20 stud farms in Normandy. The breeding conditions of these horses were monitored from 6 to 17months. They were radiographed at 6 and 17months to determine their radiographic score (RS) and its evolution. Potential risk factors were investigated using univariate and multivariate analyses. The prevalence of JOCC was 48% at 6months and 42% at 17months. Between 6 and 17months, the RS changed (for better or worse) in 52% of yearlings.The main risk factors leading to deterioration in the RS were traumatic. ‘Mixed housing’ during winter, pastures with rough ground and a bad RS at 6months were significantly associated with deterioration in RS between 6 and 17months. In the multivariate analysis, the breed was not significantly associated with any evolution in the yearlings’ RS.This study provides some indications on protective measures to prevent the worsening of JOCC lesions between 6 and 17months, a crucial period since it precedes the sale of yearlings and the beginning of training.

The Normandy field study on juvenile osteochondral conditions: Conclusions regarding the influence of genetics, environmental conditions and management, and the effect on performance

Juvenile osteochondral conditions (JOCC) have a major impact on the equine industry and include many musculoskeletal disorders of the young horse, of which osteochondrosis (OC) is the most prominent. The Breeding, Osteochondral Status and Athletic Career (BOSAC) project is the first large, comprehensive, longitudinal field study on the subject conducted in three breeds of performance horses (Thoroughbreds, Standardbred Trotters and Warmbloods) that were monitored in their natural environment where they were reared under common field conditions.The BOSAC study used a radiographic protocol designed for field use coupled to an internally validated severity scoring system, providing weighted radiographic findings as the primary outcome measure. The natural courses of various JOCC appear to differ, according to the joint and condition involved. Genetically, there were also large differences with moderate heritabilities in the tarsocrural and metacarpophalangeal/metatarsophalangeal joints and virtually no heritability for femoropatellar OC. There was a strong influence of exercise history (as an environmental condition) on the manifestation and natural course of JOCC. In the younger age class (<6months) lack of exercise or irregular exercise had a negative effect, as had exposure to excessive exercise. In the yearling category, (exercise-associated) intrinsic trauma seemed to be the most important negative factor. In terms of later function, the association of a poor radiographic score with poorer performance in racing Trotters could be demonstrated.

Genetic parameters of juvenile osteochondral conditions (JOCC) in French Trotters

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, comprising representative samples of the Trotter population, as well as material from auctions. Horses were aged 6–24months and were either not yet in training or just beginning training.Radiographs were taken of fore and hind feet, including proximal interphalangeal (pastern) joints, metacarpophalangeal and metatarsophalangeal (fetlock) joints, tarsocrural (hock) joints, carpi and femoropatellar (stifle) joints. The threshold model used included sex, age, region and month of birth, sampling group and sire (n=159) with all inter-sire relationships. The main results were a moderate heritability for findings in the hind fetlock (0.29) and the hock (0.19). There was a weak genetic correlation between findings in fetlocks and hocks (0.26). Higher heritability was found for findings in the hock (0.37 for findings in the distal row and 0.49 for the proximal row of tarsal bones) in that part of the data (699 horses) in which it was possible to integrate the grade, bilateral occurrence or not, and distal or proximal location of the lesions. It is possible to use these genetic parameters in breeding selection with more efficiency when detailed phenotypes are considered.

Influence of juvenile osteochondral conditions on racing performance in Thoroughbreds born in Normandy

The relationship between osteoarticular status and future athletic capacity is commonly accepted in equine practice, but there is little to support this belief in Thoroughbreds. The objective of this study was to assess the prevalence of juvenile osteochondral conditions (JOCC) in Thoroughbred yearlings and to investigate the significance of these with regard to subsequent racing performance. The radiographic files from 328 Thoroughbred yearlings born in Normandy were assessed in a consistent manner and entered into a database together with racing records. Logistic regression models were used to quantify the association between each radiographic parameter and racing performance (raced/not raced, placed/not placed, performer/not performer) at 2, 3, 4 and 5years of age.The front fetlock (30.2% of horses), the dorsal aspect of the hind fetlock (18%), the carpus (15.9%) and the distal part of the hock (15.5%) were the most commonly affected joints. Most horses (87.5%) raced either in turf flat races or in hurdle races. Starting a race at 2years old was more frequent for yearlings without radiographic findings (RF) on the carpus or with less than one RF of moderate severity. The proportions of horses placed at 3years old decreased with increasing number or severity of RF. In racing horses, there was no association between the presence of RF and earnings. The radiographic score, calculated as the sum of all the severity indices found on the radiographic file of the horse appeared well correlated with performance. Using this synthetic index might help veterinarians to evaluate radiographs of Thoroughbred yearlings for potential buyers.