Stenosing tenosynovitis, commonly known as trigger finger or trigger thumb, involves the pulleys and tendons in the hand that bend the fingers (see Diagram 1 and 2). These tendons act like long ropes connecting the forearm muscles with the bones of the fingers and thumb. The pulleys form a tunnel that allows easy gliding of the tendons against the bone.
Trigger finger/thumb occurs when a nodule (knot) or swelling develops on the tendon. The local swelling causes difficulty of the tendon to squeeze through the opening of the tunnel (flexor sheath) which causes pain, popping, or a catching feeling in the finger or thumb (see Diagram 2). When the tendon catches, it produces inflammation and more swelling. This leads to a vicious cycle of triggering, inflammation, and swelling. With advanced disease the finger may become stuck (locked) causing difficulty to straighten or bend the finger.
The causes for this trigger finger/thumb are not always clear. There are associations however to conditions such as rheumatoid arthritis, gout, and diabetes.
Symptoms and Signs
Symptoms may begin with discomfort at the base of the finger or thumb. A knot or thickening may be found in this area. Once the finger begins to trigger or lock, the patient may experience symptoms at the middle knuckle of the finger or the tip knuckle of the thumb.
The goal of treatment in trigger finger/thumb is to eliminate the catching or locking and allow full movement of the finger or thumb without discomfort. Swelling around the flexor tendon and tendon sheath must be reduced to allow smooth gliding of the tendon. The wearing of a splint or taking anti-inflammatory medication by mouth or an injection into the area around the tendon may be recommended to reduce swelling. Treatment may also include changing activities to reduce swelling.
If non-surgical forms of treatment do not improve symptoms, surgery may be recommended. This surgery is performed as an outpatient. The goal of surgery is to open the first pulley so the tendon will glide more freely. Active motion of the finger generally begins immediately after surgery. Normal use of the hand can usually be resumed once comfort permits. Some patients may feel tenderness, discomfort, and swelling about the area of their surgery longer than others. Occasionally, hand therapy is required after surgery to regain better use.