Transfer of the insertion of the extensor carpi ulnaris into the tendon of the extensor pollicis brevis may be used to restore opposition of the thumb.
The natural insertion of the short extensor of the thumb has an ideal location for this purpose. It helps to bring the thumb into complete pronation when the force of pull is directed properly. The motor—the extensor carpi ulnaris—was found to be strong enough to produce and maintain an almost full range of pronation angulation motion of the thumb in a group of patients with isolated median or combined median-ulnar palsy. The loss of the original functions of both muscles used to regain opposition did not cause undesirable side effects and did not alter the muscle balance of the hand.
The results in seventeen patients were excellent in nine and good in eight.