A loose, weak thumb after a crash may mean a torn ligament
Insight from a hand surgeon and a hand therapist on thumb ligament tears
Your thumb can get forced away from your hand in a crash, hurting a ligament at its main knuckle. This band is the ulnar collateral ligament. It keeps your thumb steady when you pinch your keys, hold a cup or open a package. A partial tear may heal in a cast or splint. Surgery may be needed for a full tear, or when the ligament tears away with a chip of bone. What matters most is whether the joint stays stable. [1]
Explain what you can't pinch or grip
Tell your hand doctor exactly which tasks hurt or feel weak. Ask if the ligament is partly or fully torn. Find out whether the joint felt loose during the exam. An X ray can check for a tiny piece of bone still attached to the ligament. Other scans may be used if the diagnosis isn’t clear. Don’t keep bending your thumb sideways to test it yourself. [1]
Wear the splint the way you were told
Find out if the splint has to stay on while you sleep, wash and go about your day. Hold off on gripping and pushing against resistance until you’re cleared. If you need surgery, ask how the repair changes the timeline for keeping the thumb still and for therapy. A hand therapist can help bring back motion and pinch without straining the ligament as it heals. Let the therapist know which tasks matter most to you at home and at work. [1]
Go back if the thumb still feels unsteady
Contact the hand team if your thumb still feels loose or the splint damages your skin. Do the same if your pinch isn’t getting stronger as expected. Get checked urgently if the thumb turns pale or cold, goes numb for the first time, or swells and hurts badly. Waiting too long for care can leave the thumb with lasting looseness. [1]
Ask the hand team
- Is the joint stable? Is there a piece of bone involved?
- Is a splint enough, or do you advise surgery to repair it?
- When can I safely pinch, grip and drive?
Track two pinch tasks
Pick two pinching tasks you can’t manage right now and write them down. Check them over time to see how you’re healing. [1]
Sources and further reading
This guide offers general education from hand surgery and hand therapy. If your thumb feels unstable after an injury, have it checked soon. Stick with the splint and exercise plan you were given.
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