Skier's Thumb (Thumb UCL Tear)

What it is

The ulnar collateral ligament (UCL) connects the thumb to the hand on the side facing the index finger and lets the thumb act as a stable post when you pinch. It is the most commonly injured thumb ligament. The radial collateral ligament on the other side can also tear, though less often.

What causes it

Falling with a ski pole in your hand, jamming the thumb into the ground, a ball, or another player, or any force that bends the thumb into an extreme position.

Symptoms

• Swelling and bruising at the base of the thumb
• Pain that may settle within a week or two
• Ongoing weakness or pain with pinching, writing, turning a doorknob, or holding a glass

Diagnosis

X-rays check for a fracture, and an examination of the joint's stability shows whether the ligament is torn.

Treatment

Some tears heal in a splint or cast; others need surgical repair. If an old injury has not healed, the ligament can be reconstructed with a tendon graft. If arthritis has developed in the joint, fusing it may be the best option.