Pancarpal Arthrodesis for Delayed Antebrachiocarpal Hyperextension Instability After Juvenile Forearm Fracture Repair in a Maltese Dog

Delayed carpal instability after healed juvenile antebrachial fractures presents a diagnostic and surgical challenge when retained implants occupy the site required for arthrodesis. A 3-year-old, 2.58 kg, neutered male Maltese dog presented with left forelimb lameness after bilateral radial–ulnar fracture repair during skeletal immaturity. Before implant removal, radiography and dynamic fluoroscopy localised hyperextension instability and subluxation to the antebrachiocarpal joint. Staged implant removal was selected because immediate loss of plate support and residual screw holes raised concern about temporary bone vulnerability. Intermediate screws were removed first, leaving one proximal and one distal screw in each plate. Both plates and all accessible remaining screws were removed 28 days later; contralateral removal was elective at the owner’s request. No perioperative antebrachial fracture was documented. A distal left screw head fractured during removal, leaving an intraosseous shaft that did not interfere with subsequent fixation. Left pancarpal arthrodesis was performed 68 days after the second removal procedure, with an immediate postoperative angle of approximately 12°. Gait lameness was absent by postoperative day 40. At day 75, intermittent limb elevation while standing and discomfort during manipulation persisted, although walking and trotting were free of lameness. Plate fracture was identified at approximately 38 months, with maintained alignment and apparent clinical stability; monitoring without revision was selected. Satisfactory limb function persisted at approximately 48 months. This unusual case documents localisation of postoperative carpal instability, the rationale for staged implant management, and long-term function after pancarpal arthrodesis. The contribution of staging to refracture prevention remains unquantified.