Complex dorsal dislocation of the thumb metacarpophalangeal joint.

Complex dorsal dislocation of the thumb metacarpophalangeal joint is an infrequently reported injury. Distinction from its simple counterpart is facilitated by specific physical and radiographic findings. The presence of skin dimpling without gross joint deformity represents physical evidence of a complex lesion. This diagnosis is corroborated by radiographs that reveal a dorsal dislocation associated with joint space widening and interposition of one or both sesamoids. The current treatment of choice is immediate operative reduction followed by a brief period of immobilization. Surgery may be performed through a volar, lateral, or dorsal incision. We favor the dorsal approach, in that it provides excellent exposure while reducing the risk of neurovascular injury.