Hypoplasia of bilateral humeral trochlea associated with bilateral ulnar nerve palsy.

We document a case of bilateral ulnar nerve palsy that developed in an 27-year-old Japanese man who had bilateral hypoplasia of the humeral trochlea. Surgical management produced good results regarding the ulnar nerve palsy. The pathogenesis of the nerve paresis in this particular condition is discussed. There have been no reports outside Japan. Whether this deformity occurs only in persons of Japanese extraction or is simply overlooked by foreign surgeons is an interesting question.