TARDY ULNAR NERVE PALSY CAUSED BY CUBITUS VARUS DEFORMITY

Fifteen patients with tardy ulnar nerve palsy caused by cubitus varus deformity were studied. All patients had a history of previous fractur e of the humerus during childhood. The mean interval between fracture and onset of symptoms was 15 years. The severity of the palsy was clas sified as McCowan's grade I in 12 patients, grade II in 2 patients, an d grade III in 1 patient. The mean carrying angle was - 2 degrees befo re surgery. X-ray films showed a shallow ulnar nerve groove, a dysplas tic humeral trochlea, medial shift of the ulna, and deformity of the m edial epicondyle. The ulnar nerve was explored in all but one patient. Operative findings suggested that the main cause of the palsy was com pression by a fibrous band running between the two heads of flexor car pi ulnaris. Surgical steps included release of the fibrous band in 14 patients with anterior subcutaneous transposition of the ulnar nerve i n 5 of those patients. A corrective osteotomy was done in 1 1 patients who requested correction of the varus deformity. Traumatic cubitus va rus deformity should be recognized as another cause of cubital tunnel syndrome.