What is a common sign of gamekeeper's thumb?

A common sign of gamekeeper's thumb is the presence of an abducted thumb accompanied by pain at the metacarpophalangeal (MCP) joint. Gamekeeper's thumb is an injury to the ulnar collateral ligament of the thumb, which often occurs due to a sudden forceful abduction of the thumb, typically seen in activities that involve gripping or twisting motions.

When the ulnar collateral ligament is injured, the thumb may be positioned in an abducted posture, and the affected individual usually experiences significant pain localized around the MCP joint of the thumb. This presentation helps clinicians identify the injury during a physical examination.

The other potential signs associated with thumb injuries may not highlight the specific characteristics of gamekeeper's thumb as well as the abducted thumb position with joint pain does. For instance, while inability to extend the thumb could indicate other forms of ligament injury or tendon issues, it does not specifically indicate gamekeeper's thumb. Similarly, swelling of the wrist may be associated with various injuries but does not specifically relate to the ulnar collateral ligament injury. Flexion deformity at the PIP joint is more indicative of other conditions, further distinguishing the signs of gamekeeper's thumb from these other scenarios.