Carpometacarpal joint arthrodesis to treat a luxation of the fourth carpal bone in a filly

A 1-month-old Paint filly was diagnosed with a latero-distal luxation of the fourth carpal bone associated with avulsion fractures of the third and fourth carpal bones and rupture of intercarpal ligaments based on clinical, radiography and computed tomography examination. A carpometacarpal (CMC) joint arthrodesis was performed using a lateral 3.5 mm 5-hole Locking Compression Plate (LCP) T-plate and a medial 3.5 mm 5-hole narrow LCP plate associated with mediocarpal arthroscopic exploration. An external coaptation was maintained for 6 weeks. No complication was reported and the filly was full loading the day after surgery. Radiographical follow-up was available 6 and 14 weeks after surgery showing an intact construct and stable fixation with a complete fusion of the lateral part of the carpometacarpal joint at 14 weeks postoperatively. The filly was sound on pasture without angular deformity 4 months after surgery. Luxation of the fourth carpal bone was successfully stabilised using two LCP plates, leading to complete soundness and preservation of middle carpal joint motion.