Factors affecting the functional results of open reduction and internal fixation for fracture-dislocations of the proximal interphalangeal joint.

To clarify the factors affecting functional results of fracture-dislocations of the proximal interphalangeal (PIP) joint treated by open reduction and internal fixation (ORIF), 60 patients, including 38 patients with a dorsal fracture-dislocation and 22 with a pilon fracture, were analysed. The mean ratio of articular surface involvement was 48.5% and a depressed central fragment existed in 75.3% of the cases. ORIF was performed in 47 patients through a lateral approach using Kirschner wires and in 13 through a palmar approach using a plate or screws. The mean flexion, extension and range of motion (ROM) of the PIP joint was 89.5°, 11.5° and 78.0°, respectively. Stepwise regression analysis revealed that a delayed start of active motion exercise after surgery, elderly age and ulnar ray digit were factors affecting functional outcomes. Although ORIF allows accurate restoration of the articular surfaces, an early start of motion exercise is essential for good results.