Arthroscopic mosaic arthroplasty in the equine third carpal bone.
Authors: Hurtig M, Pearce S, Warren S, Kalra M, Miniaci A
Journal: Veterinary surgery : VS
Summary
# Arthroscopic Mosaic Arthroplasty in the Equine Third Carpal Bone Focal cartilage defects in the carpus represent a significant clinical challenge, prompting investigation into whether mosaic arthroplasty—a technique successfully used in human orthopaedics—could provide a durable solution for weight-bearing joints in horses. Hurtig and colleagues transplanted autogenous osteochondral grafts harvested arthroscopically from the femoropatellar joint into defects created in the third carpal bone of six horses, monitoring graft integration and cartilage quality over nine months using histology, histomorphometry, and biochemical analysis of proteoglycan and collagen composition. All horses recovered soundly within three weeks, and repeat arthroscopy at six months showed intact grafts with good bony integration by nine months; however, marked proteoglycan loss from the transplanted cartilage developed despite minimal inflammatory repair response, with degenerative changes evident histologically in one-third of grafts. The findings suggest that whilst the technique is technically feasible with modified instruments, site-matching for cartilage thickness and biochemical properties is essential—proteoglycan depletion likely resulted from either mechanical trauma during graft handling or the inability of heterotopic cartilage to remodel adequately to its new biomechanical environment. Although mosaic arthroplasty shows promise as a salvage option for creating confluent cartilage coverage when other treatments are exhausted, the early cartilage degeneration observed indicates current application should remain cautious and selective rather than routine for carpal lesions.
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Practical Takeaways
- •Mosaic arthroplasty can achieve early soundness and bony integration in carpal defects, but cartilage quality deteriorates over 9 months due to biochemical mismatch with the new joint environment
- •This technique should only be considered as a salvage option when no other treatment exists, as long-term cartilage survival remains questionable
- •Successful application requires careful matching of donor and recipient site cartilage thickness, biochemical properties, and load-bearing characteristics
Key Findings
- •All 6 horses were sound at 21 days postoperatively and all 18 grafts remained intact at 6 months
- •Bony portions of grafts integrated well with recipient sites by 9 months, but 6 grafts showed cartilage degeneration histologically
- •Marked sulfated glycosaminoglycan (proteoglycan) loss occurred in transplanted cartilage, indicating cartilage degradation despite bony integration
- •Heterotopic osteochondral grafting is technically feasible but long-term success limited by mismatch between donor cartilage properties and recipient biomechanical environment