Gradual Lengthening of the Ulna in Patients with Multiple Hereditary Exostoses with a Dislocated Radial Head

PURPOSE Multiple hereditary exostoses of the forearm typically form in the distal ulna, causing disturbances in the growth of the ulna and functional disability. Multiple hereditary exostoses inhibit the growth of the ulna, leading to an acquisition of a varus deformity in the radius, which sometimes leads to dislocation of the radial head, the development of limitations in the pronation-supination of the forearm, and cosmetic problems. MATERIALS AND METHODS We retrospectively reviewed the cases of four patients who had deformities of the forearm with radial head dislocation associated with multiple hereditary exostoses, and evaluated the radiologic and clinical results of excision of the osteochondromas from the distal ulna and gradual ulnar lengthening with an Ilizarov external fixator. RESULTS Good clinical and radiological results were obtained after a mean follow-up of 25 months. At the most recent follow-up, radial bowing, ulnar shortening, carpal slip, and the pronation/supination arch of the forearm had improved. There was little change in terms of preoperative radial articular angle and the flexion/extension arch of the elbow by the most recent follow-up. CONCLUSION Treatment of four forearms from four patients by excision of osteochondromas and gradual lengthening of the ulna with an Ilizarov external fixator spontaneously reduced dislocations of the radial heads without the need for any additional operative intervention. All patients were satisfied with the final results.