Gamekeeper's thumb

Forced abduction of the thumb may cause a partial tear or complete rupture of the ulnar collateral ligament of the metacarpophalangeal joint of the thumb

• the injury derives its' name from the fact that it used to commonly occur in gamekeepers when killing game animals by twisting their necks
• today, it more often occurs from skiing when the skier falls on an extended thumb and forces it into hyperabduction, or catches the thumb in a pole strap.

UCL injuries should be specifically sought for in any thumb injury. Stress the joint into valgus and compare laxity of the affected thumb against the other side. A partial tear will normally be painful and there will be a definite "stop" to movement.. Complete rupture may be less painful and there is often no definite "stop" when stressed.

X-rays should be performed to exclude an associated avulsion fracture.

The injury must be treated otherwise an unstable thumb will be left with impairment of pincer grip. Partial tears may be treated in a plaster splint for 2-3 weeks. Complete tears require operative repair. Small avulsion fractures may be treated conservatively in a Bennet's plaster. Larger fragments require fixation. Neglected tears may later be treated by arthrodesis or if managed early enough, by tendor transfer.

If in any doubt, review the injury in a week. A complete rupture may not always be evident at first presentation.