The management of the occasional trigger finger.

Patients will frequently see their family physician with an “occasional trigger finger,” or a finger or thumb that gets intermittently stuck in a flexed position. By attempting to extend the digit, it will often suddenly pop out to length. In some cases, the trigger finger is painful. Trigger finger usually occurs in the third or fourth digits, but it can occur in the thumb. Excessive gripping, as with a power tool or musical instrument, can increase the risk. Usual age of onset is in the 50s and 60s. Women are at higher risk, as are those with conditions such as rheumatoid arthritis (RA), diabetes, hypothyroidism and gout. It is believed that recurrent tenosynovitis will lead to narrowing of the synovial sheath below the A1 pulley, as noted in Figure 1. In some cases, the tendon enlarges and forms a nodule distal to the pulley. As the finger is flexed, the thickened section of tendon becomes trapped proximal to the narrowing at the level of the pulley. With persistence or manual extension, using the other hand, the nodule pops through the stenotic section of tendon sheath. In severe cases, however, the finger can become stuck in the flexed position, resulting in a flexion contracture. On examination there is often tenderness to palpation in the area of the A1 pulley just proximal to the metacarpal–phalangeal (MCP) joint. There may also be a palpable nodule distal to this area, and this nodule will generally move with finger flexion and extension. The differential diagnosis of trigger finger includes other conditions such as dupuytrens contracture, a thickening of the palmar fascia, which over time pulls the finger into flexion but does not cause triggering. Additionally, abnormalities of the MCP joint such as osteophytes, loose bodies or chronic subluxation can lead to triggering.