Triple joint injuries of the same digit.

This article presents a rare case of simultaneous triple joint injuries in the same digit. A 54-year-old, right-handed man sustained simultaneous triple joint injuries in a digit, composed of a fracture of the dorsal base of the distal phalanx involving one-third of the phalanx, dorsal dislocation of the proximal interphalangeal joint with a volar plate fracture, and ulnal dislocation of the metacarpophalangeal joint. Surgery was performed on the patient. Two years postoperatively, active range of motion of the distal interphalangeal joint improved from 0 degrees to 40 degrees, of the proximal interphalangeal joint improved from -20 degrees to 100 degrees, and of the metacarpophalangeal joint improved from 5 degrees to 90 degrees. Grip strength was 32 kg compared to 35 kg on the nonaffected side. No ligamentous laxity was demonstrated in the finger joints. A fracture involving one-third of the phalanx may be caused by forced hyperextension of that joint. This hyperextension may result in a tear of the volar plate of the proximal interphalangeal joint, leading to a dislocation at that joint. This continuous force directs the metacarpophalangeal joint in a slight ulnal shift, and may result in rupture of the medial collateral ligament in the metacarpophalangeal joint. To our knowledge, this injury has not been reported in the literature.