Trigger Finger and RA

Trigger finger (also called stenosing tenosynovitis or stenosing tendovaginitis) is a painful condition in which a finger or thumb becomes “locked” in place after it has been flexed. There may be clicking, popping, or a catching sensation in the affected finger, which becomes difficult to straighten without assistance. Some patients may experience stiffness and reduced motion without the characteristic catching or locking.

Stenosing tendovaginitis (i.e., narrowing inflammation of the tendon sheath) can affect any of 23 extrinsic tendons that power the wrist and hand. However, trigger finger most commonly affects the little finger, ring finger, or thumb. Additional symptoms include a bump or lump (nodule) at the base of a finger near the palm, tenderness, or lingering soreness at the base of a finger or thumb.

What causes trigger finger?

Trigger finger is caused by inflammation and/or hypertrophy (enlargement) of the tendon sheath. This inflammation narrows the space in the tendon sheath, which acts like a tunnel through which the tendon glides, and progressively restricts the motion of the flexor tendon passing through the wrist or hand.

A tendon is the strong tissue that attaches muscle to bone and helps us move parts of our body. When a muscle in the forearm contracts and pulls on the tendon attached to a finger, it causes that finger to bend (flex). A tendon which travels through a narrowed sheath may be able to move in one direction but be unable to slide back into its original, neutral position. This causes the finger to remain in a flexed position.

Who gets trigger finger?

Although anyone can develop trigger finger, it occurs more frequently in women than men (4:1 ratio), especially in women over the age of 40, and in people diagnosed with diabetes, rheumatoid arthritis, hypothyroidism, amyloidosis, or carpal tunnel syndrome. More than 65% of patients with rheumatoid arthritis will develop some form of tenosynovitis of the hand or wrist (Skirven, 2011).

Research shows increased risk of developing problems with tendons in the hand and wrist in people who perform highly repetitive and forceful jobs. For example, musicians, such as piano players and guitarists, exert significant stress on multiple tendons in the wrist and fingers. They are prone to developing tendonitis, especially if they dramatically increase their practice time (Amadio, 1990), and are at risk for developing trigger finger.

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Trigger Finger: A Complication of RA and Diabetes