Complete Avulsion of the Extensor Mechanism of a Finger with Simultaneous Dislocation of the Proximal Interphalangeal Joint

We report a rare case of open dislocation of the proximal interphalangeal (PIP) joint, associated with simultaneous avulsion of the central band and distal insertion of the extensor mechanism, rapture of the proximal volar plate, and rapture of the ulnar collateral ligament of the PIP joint. Although isolated IP joint injuries are common, they rarely occur simultaneously in a single finger. Even more rarely are they accompanied by a complete avulsion of the extensor mechanism. Operative restoration of the injured structures is a necessity in order to achieve a good functional outcome. An initial forceful flexion of the finger resulting to rapture of the extensor apparatus and then followed by finger hyperextension and PIP joint dislocation is our perception of the possible mechanism of this extremely rare injury.