Trigger Finger


What is it?

Stenosing tenosynovitis, commonly known as “trigger finger” or “trigger thumb”, involves the pulleys and tendons in the hand that bend the fingers. The tendons work like long ropes connecting the muscles of the forearm with the bones of the fingers and thumb. In the finger, the pulleys are a series of rings that form tunnels through which the tendons must glide, much like the guides on a fishing rod through which the line must pass. These pulleys hold the tendons close against the bone.The tendons and the tunnel have a slick lining that allows easy gliding of the tendon through the pulleys (see Figures 1 & 2).

As illustrated in Figure 3, trigger finger occurs when the tendon that flexes the finger becomes inflamed or thickened and does not fit easily through the pulley at the base of the finger. Sometimes the tendon will develop a palpable nodule. Because of the increased rubbing of the tendon on the pulley as the tendon moves, one may feel pain, popping or catching in the finger.

What Causes it?

Anything that causes the flexor tendon to swell can result in trigger finger. This has been associated with repetitive activity, as well as with diabetes, rheumatoid arthritis and gout. Local trauma to the palm or base of the finger can also result in trigger finger. Trigger fingers are more common as individuals age. In many cases, the specific cause for triggering cannot be established.

Signs and Symptoms

Trigger finger may start with discomfort felt at the base of the finger or thumb. This area is often tender to local palpation. A nodule may sometimes be found in this area. When the finger begins to trigger or lock, the patient may think the problem is at the middle joint of the finger or the last joint of the thumb, since these are the joints that become stuck.

Treatment

Trigger finger is an entirely treatable condition. The first goal of treatment is to decrease the swelling in the flexor tendon and thus decrease its size and stop it from rubbing on the pulley and catching. This can often be accomplished with a combination of cortisone injections, splinting, and anti-inflammatory medications. Activity modification can often also be helpful. Approximately eighty percent of patients with trigger finger will be permanently cured with one or two cortisone injections over a period of several months. In patients that are not better after two cortisone injections, surgery is usually the best option. The purpose of the surgery is to divide the first pulley and allow more room for the tendon. This surgery is done under regional IV block anesthesia, which involves numbing the hand and wrist. Active motion of the fingers is allowed immediately after surgery. There is generally some tenderness in the palm, which persists for several weeks. Once the tendon has enough space and it is not constricted, the swelling in the tendon generally resolves. Occasionally, hand therapy is required after surgery if the patient has stiffness or tenderness.