The cases of four patients with carpometacarpal fracture-dislocations of the ulnar four joints are reported, in all of whom there was extensive additional trauma. Open reduction was necessary in three patients, and only one was treated successfully by a closed reduction. He then had persistent but painless subluxation of the metacarpal bases. On end-result evaluation, two of the other three patients had occasional discomfort and diminished grip strength. One patient had a diminished range of motion of the wrist joint at one-year follow-up, and one patient had narrowing and sclerosis of the carpometacarpal joints.