Post mortem evaluation of palmar osteochondral disease (traumatic osteochondrosis) of the metacarpo/metatarsophalangeal joint in Thoroughbred racehorses

• Published in: Equine veterinary journal 2009-04, Vol.41 (4), p.366-371
• Main Authors: BARR, E. D., PINCHBECK, G. L., CLEGG, P. D., BOYDE, A., RIGGS, C. M.
• Format: Article
• Language: English
• Subjects: Animals; Foot Injuries - pathology; Foot Injuries - veterinary; horse; Horse Diseases - pathology; Horses; Male; metacarpo-/metatarsophalangeal joint; osteoarthritis; Osteochondrosis - pathology; Osteochondrosis - veterinary; palmar/plantar condyle; Thoroughbred
• ISSN: 0425-1644; 2042-3306
• DOI: 10.2746/042516409X368372

Summary Reasons for performing study: Thoroughbred racehorses are commonly affected by subchondral bone injury, but the exact prevalence and the distribution of palmar/plantar osteochondral disease (POD) lesions are unknown. The relationship between pathologies has not been elucidated, although it is widely accepted that POD is a manifestation of traumatic overload arthrosis. Hypothesis: There is an association between grade of POD and other pathologies affecting the third metacarpal and metatarsal (MC/MTIII) condyles (wear lines, cartilage loss, marginal remodelling, dorsal impact injuries and linear fissures). Objectives: To evaluate the pathology found affecting the distal MC/MTIII condyles of Thoroughbred racehorses at post mortem examination, to describe the prevalence and distribution of POD lesions within a population of racing Thoroughbreds and to determine relationships between pathologies of the distal condyles of the third metacarpal and metatarsal bones. Methods: The metacarpo/metatarsophalangeal joints of 64 Thoroughbred racehorses were examined at routine post mortem examination and graded for third metacarpal and metatarsal condylar pathology. Associations between pathologies were determined. Results: POD had a within horse prevalence of 67%. There was a significant linear relationship between grade of POD and grades of wear lines, cartilage ulceration and dorsal impact injuries. There was a significant relationship, but this was not linear, between grade of POD and grade of linear fissures. Using ordinal logistic regression, compared to condyles with grade 0 or grade 2 linear fissures, condyles with grade 1 linear fissures were found to be more likely to have a lower POD grade. Potential relevance: POD can be considered to be a manifestation of traumatic overload arthrosis, but the role of subchondral bone adaptation is complex and warrants further investigation.