Skier’s thumb is a common hand injury involving damage to the soft tissue structures that stabilize the thumb joint. While often associated with falls during winter sports, it occurs in any activity involving forced thumb movement. Untreated Skier’s thumb can lead to long-term instability and weakness, making accurate diagnosis and timely treatment important for a full recovery.
Understanding the Injury Mechanism
Skier’s thumb is an acute injury to the Ulnar Collateral Ligament (UCL) of the thumb’s metacarpophalangeal (MCP) joint. The UCL is a band of tissue on the thumb’s inner side that stabilizes the joint against outward stress, which is necessary for effective grasping and pinching. The injury occurs when the thumb is forcefully pulled away from the hand in hyper-abduction and hyperextension.
The classic scenario involves a skier falling while holding a pole; the pole acts as a fulcrum, violently bending the thumb backward and outward. This sudden, forceful pulling causes the ligament to stretch, partially tear, or completely rupture at its attachment point on the proximal phalanx. Although named for skiing, this mechanism is frequent in other sports like football, rugby, and basketball, or from falling onto an outstretched hand.
Recognizing the Signs and Symptoms
Patients typically experience immediate, localized pain at the base of the thumb, specifically on the side nearest the palm. Following the injury, the area around the MCP joint often becomes noticeably swollen and may display bruising or discoloration. Tenderness is common directly over the damaged ligament.
The most functionally relevant symptom is instability or weakness, particularly when performing grasping or pinching motions. The thumb may feel loose or like it is “giving way,” making simple tasks like gripping a door handle or holding a pen difficult. In complete ruptures, a small, palpable lump may be felt on the inside of the thumb, indicating a specific complication called a Stener lesion.
Confirming the Diagnosis
A medical professional confirms the injury and assesses its severity through a physical examination and imaging studies. The physical exam includes a stability or stress test, where the doctor gently applies an outward force to the thumb to check for excessive movement in the MCP joint. This test is highly informative but must be performed cautiously to avoid worsening a partial tear.
Initial investigation involves a plain X-ray to rule out an avulsion fracture, which occurs when the ligament pulls a small piece of bone away from the phalanx. If a complete tear is suspected or the stability test is inconclusive due to severe pain, advanced imaging like ultrasound or MRI may be used. These scans visualize the ligament, helping determine if the tear is partial or complete and identifying a Stener lesion.
Treatment and Recovery Paths
Treatment is determined by the tear’s severity, classified as Grade I (stretched), Grade II (partial tear), or Grade III (complete rupture). Non-surgical management is the standard path for stable Grade I and II partial tears. This conservative approach typically involves immobilizing the thumb in a cast or specialized splint for four to six weeks.
During immobilization, patients follow a protocol of rest, ice application, and anti-inflammatory medication to manage pain and swelling. After the cast or splint is removed, physical therapy is necessary to regain full range of motion and strength. Full recovery and a return to activities may take up to three months after a partial tear.
Surgical intervention is required for Grade III complete tears or when a Stener lesion is present. A Stener lesion occurs when the torn ligament end becomes displaced and trapped outside a tendon sheath, preventing natural healing. Surgery repairs the torn ligament by reattaching it to the bone, often using sutures or anchors. Following surgery, the thumb is immobilized for four to six weeks. The extensive rehabilitation phase, including physical therapy, leads to a return to full activity typically expected around three to four months post-operation.