Thumb Sprains
A thumb sprain, or skier’s thumb, is a common injury that occurs after falling onto or impacting the thumb. If the thumb is forced backwards or to the side, a ligament sprain or tear can occur. A sprain is an injury to a ligament – a soft tissue structure that connects two bones to one another around a joint. Sprains can vary in severity from partial tears of the ligament to complete tears. The most common site of injury in the thumb is the ulnar collateral ligament (UCL) of the metacarpal-phalangeal joint. Injuries to the other side of the thumb, the radial collateral ligament (RCL) can also occur, but are much less frequent.
Some complete tears require surgery to repair. A "Stener lesion" is a situation when the torn ulnar collateral ligament gets folded backwards after tearing. A band of tissue called the adductor aponeurosis blocks the ligament from healing back to the bone. In surgery, the adductor aponeurosis is divided, and the torn ligament is sutured back to the bone.
Cause
Tears of the thumb UCL ligament occur when the thumb is jammed or forcibly bent away from the hand during a fall. A common cause is falling onto the hand while holding onto a ski pole – hence the term “skier’s thumb”. Alternatively, the ligament can slowly stretch out and wear out over time. This is referred to as a “gamekeepers’ thumb”.
Symptoms
Swelling and bruising along the inside of the thumb are commonly seen following an injury. The thumb UCL acts as stabilizing band of tissue during pinching, holding a pen, opening doors or jars, or grasping a cup. When the thumb UCL is torn, pain and weakness are often felt during these activities.
Diagnosis
X-rays are useful to evaluate for fractures or to see if a fragment of bone tore off with the ligament. Examination of the thumb is important to compare the stability (or laxity) of your injured thumb to your other side. This can often determine the severity of the injury, as a thumb with a torn ligament may be unstable. MRI can be obtained, but is not usually necessary.
Non-surgical treatment
Incomplete tears associated with a stable joint can oftentimes be treated successfully in a splint
Typically a “thumb spica splint” is worn full time for 4 weeks, then motion is started
Ligament healing usually takes 6-8 weeks
Surgical treatment
Complete tears may need to be treated surgically to restore stability to the joint
A thumb with a torn ulnar collateral ligament will be painful, weak and is at risk for developing arthritis
A tear that recently occurred can usually be treated by repairing the ligament back to the bone with sutures
After surgery, a splint is worn full time for ~4 weeks. After this, therapy is initiated to restore motion and strength. Typical ligament healing takes 6-8 weeks.
Tear of the thumb UCL results in the joint "booking open" during pinching. Image from AO Foundation
A suture anchor is placed into the proximal phalanx. The attached sutures allow for the torn ligament to be stitched back down to the the bone. Image from AO Foundation
Chronic tears may require creating a new ligament from a tendon graft
If arthritis is present, a fusion of the joint may be the best option
Dr. Schreiber is a board certified orthopedic surgeon specializing in hand, wrist, and elbow conditions. Dr. Schreiber practices at the Raleigh Orthopaedic Clinic in Raleigh, North Carolina.