Author(s): Frisbie DD, Ray CS, Ionescu M, Poole AR, Chapman PL
OBJECTIVE: To determine whether serum or synovial fluid concentrations of chondroitin sulfate epitope 846 and carboxy propeptides of type II collagen (CPII) can be used to diagnose osteochondral fragmentation (OC) in horses. ANIMALS: 38 horses with unilateral OC of the radiocarpal (n = 31) or intercarpal (33) joints and 8 clinically and radiographically normal horses. Procedures-For horses with OC, serum and synovial fluid concentrations of epitope 846, CPII, and keratan sulfate (KS) were determined, along with synovial fluid WBC counts and total protein concentrations. Serum epitope 846, CPII, and KS concentrations were measured in control horses. RESULTS: Synovial fluid epitope 846 and total protein concentrations were significantly higher in the joints with OC than in unaffected joints, but CPII and KS concentrations and WBC counts were not. Synovial fluid total protein and 846 epitope concentrations were linearly related to grade of OC. Serum epitope 846 and CPII concentrations were significantly higher in horses with OC than in control horses. Discriminant analysis allowed 27 of 34 (79%) horses to be correctly classified as having or not having OC on the basis of serum epitope 846 and CPII concentrations. CONCLUSIONS: Results suggest that serum and synovial fluid concentrations of epitope 846 and CPII are associated with OC. Increases in concentrations of epitope 846 and CPII suggest that increased synthesis of cartilage aggrecan and type II procollagen may be associated with OC. CLINICAL RELEVANCE: Measurement of serum epitope 846 and CPII concentrations may be useful in the diagnosis of OC in horses.