Irreducible distal interphalangeal joint dislocation of the finger: A new cause

Abstract

Dorsal dislocations of the distal interphalangeal (DIP) joint of the finger are almost always reducible by closed methods.’ Rarely, however, these injuries may be irreducible, requiring open reduction. To date, three causes of irreducible dorsal dislocation of the DIP joint have been described. These causes are (1) palmar plate avulsion off the middle phalanx with interposition in the joint,* (2) entrapment of the flexor digitorum profundus (FDP) tendon behind one condyle of the middle phalanx,3T4 and (3) buttonhole tear through the palmar plate.’ We have encountered a case in which the distal end of the middle phalanx became entrapped in a longitudinal split in the FDP tendon. We report this case as a fourth cause of irreducible dorsal DIP dislocation. Case Report A 20-year-old man injured his right long finger when he jammed it into the base during a head-first slide while playing softball. Physical examination revealed swelling, tenderness, and deformity about the DIP joint of the finger. There was a 7 mm laceration over the palmar aspect of the DIP joint as well. Anteroposterior and lateral x-ray films (Fig. 1) revealed a dorsal DIP dislocation. An attempted closed reduction under digital block failed, and the patient underwent surgery for an open reduction, debridement, and irrigation. The condyles of the