Dorsal buttress plate fixation for the treatment of fracture–dislocation of the fifth carpometacarpal joint with avulsion fracture of the hamate: a case report

Fracture–dislocations of the fourth and fifth carpometacarpal (CMC) joints present a complex situation. Misdiagnosis and inadequate treatment may cause malunion and residual subluxation, which lead to painful arthritis and grip weakness. Open reduction along with internal fixation is the treatment of choice, but there is no consensus on an optimal treatment approach. We applied a novel surgical technique to treat a case of a fracture–dislocation of the fifth CMC joint with avulsion fracture of the hamate using a dorsal buttress plate between the hamate and the capitate. This method allowed for achieving rigid fixation without screw insertion across the bone fragments of the hamate. We could avoid the risk of unexpected fragmentation and unexpected damage to the volar neurovascular bundles around the hook of the hamate. Six months postoperatively, bone union was achieved and the reduction of the fourth and fifth CMC joints was maintained. Range of motion of the fourth and fifth CMC joints was almost equal to that on the contralateral side. Dorsal buttress plating between the hamate and the capitate could be an alternative technique for the treatment of fracture–dislocation of the fifth CMC joint with avulsion fracture of the hamate.