Ulnar Lengthening for Negative Ulnar Variance in Hereditary Multiple Osteochondromas

Patients with multiple hereditary osteochondromas have several deformities of the forearm; these may be ulnar deviation of the wrist with a relatively shortened ulna, bowing of the radius with overall shortening of the forearm, and subluxation of the radial head. The natural history of these is progression, with impairment in function and cosmetic appearance of the upper extremity. We describe long-term follow-up of two patients who underwent ulnar lengthening to prevent radial head dislocation and three patients with radial head subluxation who did not undergo ulnar lengthening and eventually had dislocation of their radial heads. To prevent disability and improve cosmetic appearance, aggressive early treatment by lengthening of the ulna should be undertaken when the ulna falls short of the radius by 1 cm.