Gamekeeper’s thumb, sometimes called skier’s thumb, is a sprain of the ulnar collateral ligament (UCL) of the thumb. The bones that make up the palm of the hand are called metacarpals and the bones that comprise the fingers are called phalanges. The thumb has two phalanges, while the rest of the fingers have three phalanges. The joint that connects fingers to the palm are called the metacarpophalangeal (MCP) joints. The MCP of the thumb is flanked on either side by a collateral ligament, much like the knee.
The UCL of the thumb is found on the inside portion of the MCP joint or the side of the thumb closest to the other fingers. The UCL is important to the stability of the thumb and if injured, can disrupt the athlete’s ability to grip, throw, or catch an object.
The name of this injury was coined for a group of people it occurred in, namely small gamekeepers, especially rabbit keepers. Gamekeepers killed rabbits by breaking their necks between the ground and their thumbs and index fingers. Since the motion required put stress on the UCL, over time the UCL would stretch or tear.
A sprain is the stretching or tearing of a ligament and can be graded based on the severity of the damage done. A mild sprain is a mere stretch of the ligament, whereas a moderate sprain is tearing of some of the fibers, a severe sprain is the complete tear or rupture of the ligament. The mechanism causing injury here is forceful abduction (movement away from the rest of the fingers) or hyperextension.
Since a mild sprain (Grade 1) is a stretching of the ligament, the joint remains stable and there is no laxity of the ligament. However there may be mild swelling, pain with movement and tenderness over the area of the UCL on the thumb.
With a moderate sprain (Grade 2), there is some tearing of the ligament and the joint stability is compromised. An unstable joint may move beyond its natural range of motion or there may be abnormal movement during normal range of motion. In other words, the joint may slide side to side a bit when it is being bent within its normal range of flexion. There will be immediate pain, disability, and significant swelling of the thumb or the hand near the MCP joint. Considerable pain with movement of the joint and function of the joint is seriously impacted.
A severe sprain (Grade 3) or complete tear of the UCL may result in deformity, bruising, swelling tenderness and pain with movement. The ligament can tear in the middle or closer to where it attaches to the bones. Sometimes the ligament tears off a piece of bone and is called an avulsion fracture.
Football players may suffer UCL sprains of varying degrees while grabbing an opponent if the thumb gets caught in the jersey. In baseball or softball, the UCL injury may happen if the thumb gets caught on the edge of a base during a head first slide. UCL sprains are common among skiers and happen when the skier falls and lands on his hand while holding his ski pole.
The same concept also applies to hockey players, while gripping their stick during a collision or fall to the ice. Hockey players may end up with gamekeeper’s thumb as the result of a fight, while clutching the jersey of the player he is fighting. This injury can also happen to the Average Joe when falling onto an outstretched hand.
Immediate treatment for a sprained thumb is, of course PRICE (Protection, Rest, Icing, Compression, Elevation), which works for most injuries. I know I’ve talked about rest, ice, compression and elevation, but I don’t want to neglect protection from the usual treatment protocol. In the first 2-3 days after the injury, the thumb should be iced 4-5 times a day for no more than 20 minutes at a time.
For mild sprains with no instability, a few days of rest may allow sufficient healing and if there is any swelling, taping the thumb may help protect it from exacerbating the injury, especially if the athlete must continue to play while healing. Rehabilitation exercises work on range of motion and strengthening of the surrounding muscles. Squeezing a tennis ball, racquetball, foam ball or eve a rolled-up sock is a great way to work on strengthening.
If there is instability of the thumb, but no complete rupture or avulsion fracture, the athlete should be removed from play and the thumb should be immobilized in a splint or cast for up to 6 weeks to align the ligament and allow for proper healing. Surgery may be required for complete ligament tears, avulsion fracture, instability that leads to subluxation or dislocation or a chronic injury that causes functional disability.
Surgery consists of repairing the avulsed or chipped portion of the bone or repairing or replacing the torn ligament. If the sprain was moderate or severe, the thumb should be taped for additional support upon return to sport. Tape is applied in a way that restricts or prevents the thumb from hyperextending.
Current NHLer Matt Smaby of the Anaheim Ducks had surgery to repair a torn ligament in his right thumb suffered during a preseason fight on September 24. Though details aren’t known, I could speculate that a torn UCL is the injury he may have suffered.