Mosaic arthroplasty in equine stifle and fetlock joints: A retrospective study of 31 cases between 1998 and 2023.

Objective: To evaluate the clinical application of equine mosaic arthroplasty for joint surface repair, including outcomes and complications.

Study design: Retrospective clinical study.

Animals: A total of 31 horses diagnosed with subchondral bone cysts (SBCs) in the femoral condyle (22/31), distal metacarpus (7/31), or metatarsus (2/31).

Methods: Medical records of horses that underwent autologous or allogeneic osteochondral graft transplantation were reviewed. Follow-up lasted at least 12 months. Success was determined in terms of improvements in lameness and post-surgical athletic performance, classified as successful, satisfactory, or unsatisfactory.

Results: In total, 68% (21/31) of horses regained soundness and resumed athletic performance at the same or higher level than before surgery. Furthermore, 22% (7/31) and 10% (3/31) exhibited satisfactory and unsatisfactory results, respectively. Seven horses underwent follow-up arthroscopy to treat complications or residual lameness. Among horses with femoral condyle SBCs, 68% (15/22) achieved successful outcomes, compared with 67% (6/9) of those with fetlock SBCs. Age (≤3 vs. >3 years) did not appear to influence outcomes in stifle cases. Horses receiving fewer implanted grafts showed a tendency toward better recovery.

Conclusion: Mosaic arthroplasty improved lameness in 90% of this mixed-age equine population, with 68% regaining soundness and successfully returning to athletic performance. Unlike other techniques reporting success primarily in 2- and 3-year-old horses, this method could provide an effective surgical alternative for both young and mature horses with SBCs.

Clinical significance: Mosaic arthroplasty may serve as a viable surgical option for managing SBCs.