Gamekeeper’s thumb, also known as skier’s thumb, is an injury to the ligament of the metacarpophalangeal (MCP) joint of the thumb. The joint is formed at the junction of the bones at the base of the thumb, that is, the head of the first metacarpal of the hand and the base of the first phalange of the thumb, in the area known as the web space. The joint is supported and held in position by ligaments on either side of the joint, plus the ulnar collateral ligament that restricts the amount of sideways movement of the thumb, away from the hand. The ulnar collateral ligament is used whenever you grip or hold an object.
The injury first got its name because it was commonly found in Scottish gamekeepers who used to regularly break the necks of rabbits in such a way that the force required gradually weakened the ligament and resulted in a painful, unstable thumb joint. Nowadays the injury is much more likely to be an acute injury, often found in skiers as a result of a fall or catching the thumb in the ski pole loop.
The specific movement that produces gamekeeper’s thumb is the forceful abduction of the thumb, which means the movement of the thumb away from the index finger. This can tear the ligament and sometimes causes a small fracture of the metacarpal as the ligament tears away a chip of bone. This is known as an avulsion fracture.
Gamekeeper’s thumb is typically a chronic injury to the ulnar collateral ligament, while skier’s thumb best describes an acute injury. The terms are often used interchangeably.
Gamekeeper’s thumb is caused by a force that pushes the thumb sideways, away from the hand, beyond its normal range of motion. This may occur as a result of a fall, but this common injury often happens during participation in sports. Skiers, football players, and hockey players are particularly at risk.
- Pain at the point of injury
- Possible bruising
- Difficulty holding objects or gripping
- Instability of the thumb joint
- Thumb might get caught on objects, such as pockets
Early diagnosis is important in order to achieve the best results from treatment. Failure to diagnose the injury, or a decision not to treat it, will almost certainly result in permanently impaired thumb function. Proper treatment leads to a complete resumption of normal activity in nearly every case.
Your doctor will ask you about your medical history, any previous injuries to your hand or thumb, your general level of activity, the circumstances of your current injury, and the type and severity of your symptoms. Your thumb and hand will be physically examined. Your doctor will need to assess the stability of the joint. If your thumb joint is very painful the doctor may inject the area with some local anesthetic so your thumb can be manipulated in particular ways to aid with diagnosis.
X-rays will probably be taken to see if there is a bone fracture, and an MRI (magnetic resonance imaging) scan may be needed to view the soft tissues. Gamekeeper’s thumb can be difficult to correctly diagnose, particularly if no fracture is present. A condition called a Stener lesion, where a tendon gets caught between the torn ligament and its normal place of insertion on the bone, prevents the ligament from healing. This condition would not necessarily be clear on an X-ray, which is why an MRI may be necessary.
Treatment depends on the severity of the injury, your age and physical requirements, and how long before diagnosis the injury was sustained.
Initial treatment should consist of applying crushed ice, in a bag and wrapped in a towel, to the injured area. Ice can be applied for as long as is comfortable, several times a day. NSAIDs (non-steroidal anti-inflammatory drugs) will help with pain and inflammation, as can anti-inflammatory gel. Elevating the hand above the level of the heart will reduce swelling.
For a moderate injury (Grade I or Grade II) with a relatively stable thumb joint, the wrist might be placed in a cast or type of splint (thumb spica) for four to six weeks while healing takes place. If there is a fracture but the bone fragment is only minimally displaced, the joint may also be splinted. Over 90% of these injuries heal extremely well. Exercises to rehabilitate the thumb joint would begin when medically appropriate, but typically after six weeks of splint wearing. One of the most helpful exercises is to squeeze a soft ball or rolled sock. Do not begin rehabilitation exercises without your doctor’s approval, in order to avoid further damage to the joint. Physical therapy may include ultrasound and massage as well as exercise.
More severe injuries resulting in extensive or complete ligament tearing and a significantly unstable joint will most likely require surgical repair. Surgery is most effective for gamekeeper’s thumb when performed within a few weeks of the injury. The goal of surgery is to restore strength and stability to the thumb joint. The torn ligament ends would be sewn back together, if possible, or stitched to the bone. If too much time has elapsed since the injury it is unlikely that repair of the ligament would be possible, so the ligament might be reconstructed using other tissues such as a tendon, or a muscle at the base of the thumb might be extended.
Following surgery a cast or splint would have to be worn for up to six weeks. You would be advised when to begin exercises to increase the range of motion of the thumb, followed by strengthening exercises. A return to sports is normally possible about three or four months after surgery. It might be advisable to tape the thumb, at least when first returning to sporting activity.
Occasionally there may be some residual instability of the thumb, which may lead to premature development of arthritis. Any stiffness or numbness is likely to gradually resolve with time.