A torn ulnar collateral ligament (UCL) is a serious injury that can require surgery and several months of rehabilitation. The UCL is a key ligament in the thumb, responsible for stabilizing the joint and allowing for normal motion. A tear in this ligament can cause pain, weakness, and instability in the thumb. While some people may be able to return to normal activities after conservative treatment, others may require surgery to repair the damage. If you have suffered a torn UCL thumb, it is important to seek medical attention as soon as possible. Your doctor will likely recommend a course of conservative treatment, such as rest, ice, and splinting, before considering surgery. If your symptoms do not improve with conservative treatment, or if the tear is large, you may require surgery to repair the damage. Surgery typically involves reattaching the ligament to the bone or replacing it with a tendon graft. After surgery, you will need to undergo rehabilitation to restore strength and range of motion in your thumb. While a torn UCL thumb can be a serious injury, most people who undergo treatment recover well and are able to return to their normal activities. With proper medical care and rehabilitation, you can expect a good outcome following a torn UCL thumb.