Gamekeeper’s thumb or Skier’s thumb (has a more acute injury connotation) is an avulsion or rupture of the ulnar collateral ligament (UCL) of the thumb.
Officially termed in 1955 this injury was originally named after Scottish game keepers who would often use their hands to sacrifice game by twisting their necks. In common day America it is now known as “Skier’s Thumb” often caused by a skier landing on the ground with his/her hand braced on the ski pole.
The repetitive breaking-of-necks of small game (rabbits and such) resulted in chronic injury to the ulnar collateral ligament of the metacarpophalangeal joint of the thumb with weakening and eventual tear. Gamekeeping and poaching have largely fallen by the wayside as a recreational activity. This injury is now seen more frequently in skiers, and in the 80’s break dancers.
- Pain at the base of the thumb between the thumb and index finger; including pain with thumb movement
- Inability to grasp with thumb or a weakness to grasp
- Tenderness along the inside of the thumb
The aim or imaging is to identify a fracture; determine if there is instability (joint space widening) and identify a Stener lesion. A classification into six types has been proposed by Hintermann. If a small avulsion fracture is present, then this will be seen at the ulnar corner of the base of the proximal phalynx.
Ultrasound: Ultrasound is helpful in identifying not only the tear but also whether or not a Stener lesion is present. Clearly this requires a knowledge of local anatomy and use of a high frequency probe.
MRI: MRI is increasingly used to asses x-ray occult injuries to the ulnar collateral or to attempt to identify a Stener lesion. Findings include:
- discontinuity of the ligament +/- joint capsule
- bone marrow oedema and fracture
- Stener lesion 4
Treatment depends on degree of unstability.
For stable lesions treatment is immobilization with cast.
Indications for surgery:
- Gross radiographic instability (which usually represents tears of both the proper and the accessory collateral ligaments)
- Presence of palpable torn ligament ends (Stener lesion) [in excessive swelling the Stener’s may not be palpable]