Collateral ligament avulsion fractures from the heads of the metacarpals of the fingers.

Nineteen patients with collateral ligament avulsion fractures from the metacarpal heads of the fingers were treated during a 6 year period. Seven undisplaced fractures were initially treated conservatively. Four united with full movement. Three required internal fixation for symptomatic non-union and healed without problems. Eleven patients with displaced fractures were treated by primary internal fixation using a single lag screw through a dorsal approach. Seven of these achieved a full range of movement of the injured digit by 3 months. Four patients failed to regain full flexion of the metacarpophalangeal joint. One patient with a displaced and comminuted fracture was treated with internal fixation at 8 weeks when the fragment had consolidated. As with similar fractures from the proximal phalangeal bases, these fractures are prone to non-union when treated conservatively, even when undisplaced. If fixation becomes necessary, the delay of a trial of conservative treatment does not appear to affect the outcome. Internal fixation of displaced fractures allows gentle mobilisation and facilitates union.