Twenty patients who had a dislocation of one or all of the medial four carpometacarpal joints were followed for an average of 6.5 years (range, 1.5 to 20.5 years). Fifteen patients were treated with open reduction and internal fixation during the first three weeks after injury and the long-term result was excellent in thirteen of them. Three of the four unsatisfactory results were in patients who had injuries to the normally rigid second and third carpometacarpal joints or had a concomitant ulnar-nerve injury.