Chronic posttraumatic radial instability of the thumb metacarpophalangeal joint.

Radial collateral ligament injuries accounted for 35% of 26 patients undergoing surgery for lateral instability of the thumb metacarpophalangeal joint in a 3-year period. Nine patients with chronic radial instability presented with significant disability but with a symptom complex distinct from the weak pinch and grasp of chronic ulnar instability. Functional and clinical stability was obtained in these patients with a surgical procedure that consisted of repair of the callateral ligament at the site of injury, distal advancement of the abductor pollicis brevis tendon, and repair of the abductor aponeurosis.