Skier's (Gamekeeper's) Thumb

Skier's thumb is a tear of the ligament on the inner side of your thumb's main knuckle (the joint where the thumb meets the hand). The classic mechanism is exactly what the name suggests: a ski pole strap catches the thumb and yanks it sideways during a fall. The ligament is called the ulnar collateral ligament (UCL): it's what stops your thumb from bending too far away from your other fingers and what gives a strong pinch its stability. Gamekeeper's thumb is the same injury when it happens slowly over time from chronic strain, named after the British game wardens who used to wring rabbits' necks. When the UCL tears all the way through, your thumb feels weak, painful, and unstable when you try to pinch or grip.

There's one specific pattern that always needs surgery: a Stener lesion. That's when the torn end of the ligament has flipped over and gotten stuck on the wrong side of a nearby muscle sheath. In that position the ligament physically can't reach back to its attachment to heal on its own, so surgery is the only way it gets fixed.

• Pain and swelling on the inner side of the thumb's main knuckle (the MCP joint) after a fall or forceful bending
• Weakness of pinch grip, trouble turning a key, opening a jar, or holding a piece of paper between your thumb and index finger
• A feeling of looseness or instability when you pinch or grip
• Bruising along the inner edge of the thumb
• Tenderness right over the ligament when you press on the inner side of the knuckle
• Pain that worsens when the thumb is bent sideways away from the other fingers

A focused physical exam of the thumb checks how stable the ligament is, comparing the injured thumb with the other side. Looseness on that exam points to a complete tear. An X-ray can confirm the diagnosis, and an MRI can identify a Stener lesion before surgery, important because that finding shifts the plan from cast to operating room.

The right treatment depends entirely on how badly the ligament is torn. A partial tear can heal on its own if you hold it still. A complete tear, and especially a Stener lesion, will not, and those need surgery. The exam and imaging sort out which group you are in, and that answer points the way.

If the ligament is torn all the way through, holding it still will not bring the torn ends back together, and a Stener lesion physically blocks the ligament from reaching its attachment to heal. In those cases the next step is surgery, covered in the section below.

Complete UCL tears and any Stener lesion need surgery. The repair stitches the torn ligament back to its attachment point, often anchored with a small bone anchor. Without surgery, a complete tear leaves the thumb chronically weak and unstable, and you lose much of your pinch strength permanently.

External patient-education references and related OSI pages for additional background:

• AAOS OrthoInfo, patient education library
• OSI glossary, orthopedic terminology in plain language