trigger thumb (snapping thumb)
What are the symptoms of trigger thumb?
Many patients feel soreness at the base of the thumb.
The most common symptom is a (more or less) painful clicking or snapping when the affected thumb is extended from a flexed position.
The symptoms are usually more pronounce in the morning.
The narrowing of the tendon sheet refers to mechanical impingement of flexor tendon of the thumb at the level of the A1-pulley. (Look at the arrow in the figure)
In medicine it is called: "stenosing tendosynvoitis"
More often than is observed on the finger the thumb locks at the end joint in an extended or flexed position
What causes trigger thumb?
Trigger thumb is often caused by repetitive and forceful use of the thumb. A high risk to get a trigger thumb is by doing unfamiliar work with a hand-held tool. (or sport like tennis or golf). But there is also a hereditary cause of trigger finger and trigger thumb.
In some Patient it seems that there is an unknown rheumatic disease with coexistence of trigger finger, de Quervain's disease, carpal tunnel syndrome and epikondylitis.
Is a recovery from trigger thumb with operation possible?
Yes! Many trigger thumbs in adults can be successfully treated without an operation! The non operative treatment follows the same principles as in the trigger finger:
Avoiding repetitive gripping
Warm hand bath
Anti inflammatory medication
Be patient! The time it takes to recover from a trigger thumb varies considerably. It depends on the severity of the narrowing of the tendon sheath.
What is done during surgery?
It is made a small incision at the base of the thumb. The figure shows the skin incision.
Under the skin the fatty tissue is seen. (Yellow)
A small scalpel is used to divide the first annular ligament of the thumb. The red arrow in the figure pointed to the divided pulley.
The last image shows the skin suture
Is a particular risk in the operation of a trigger thumb?
In principal: There are the same complications possible during a release of trigger finger (open division of A1-pulley) and the same operation on the thumb.
In both operations digital nerve injury is a rare, but a serious complication. It happens more likely during an operation on the thumb. Scar tenderness at the base of the thumb is during manual work more disturbing then it is in a finger.