Successful total hip arthroplasty in a miniature horse.

OBJECTIVE: To describe the surgical treatment, postoperative management, and outcome of a miniature horse undergoing total hip arthroplasty (THA). STUDY DESIGN: Case report. ANIMALS: A 4-year-old miniature horse stallion weighing 85 kg. METHODS: The horse presented with left coxofemoral luxation of ~6 weeks duration. Computed tomography confirmed craniodorsal luxation with marked degenerative changes to the femoral head. The horse underwent THA using cementless press fit implants, including an interlocking lateral bolt for the femoral stem. RESULTS: The horse recovered well from anesthesia but suffered a coma-like episode after returning to a stable. Following treatment of presumed hypovolemia, the horse regained normal mentation and was discharged 24 days after surgery. At reassessment 12 weeks postoperatively, the horse was 2/10 left hind limb lameness at trot with good healing of the surgery site. Five months postoperatively mild (1/10) lameness remained at trot but the horse was able to canter normally on both reins. The horse has since been managed normally with no veterinary treatment required for 32 months postoperatively. CONCLUSION: Total hip arthroplasty is possible in miniature horses weighing up to 85 kg and can result in a good long-term outcome.