Trigger Finger or Trigger Thumb results from constriction of the flexor tendon sheath, which produces swelling of the corresponding tendon. The flexor tendon helps the finger or thumb to bend, and its sheath is the tunnel-like opening that the tendon glides through. Irritation as the tendons slip into the tunnel causes the opening of the tunnel to constrict, or the tendon to thicken in order to facilitate passage through the tunnel. Repetitive trauma or friction may sometimes result in the formation of a tender “nodule” at the base of the affected finger over the metacarpophalangeal joint. While flexion can be attained, extension is usually difficult and painful – producing a “trigger” or flicking motion as the nodule passes through the constricted area.
Stiffness and “catching” may become worse after a period of inactivity, such as in the morning. When it loosens throughout the day, it may feel unstable. In severe cases, the finger may become stuck in a bent position.
Those at Risk
A trigger finger is a common problem that most often affects women – between the ages of 40 and 60. While the cause is unclear, it appears to commonly affect patients with other medical problems such as diabetes and rheumatoid arthritis, as well as those with a history of repeated injury to the area.
Trigger finger or thumb is easy to diagnose and is usually suspected when the symptoms are described. A physical examination of the affected area can usually confirm it without further tests.
In mild cases, resting the affected hand will usually eliminate the problem. Over the counter anti-inflammatory medication such as Tylenol® or Advil® may be recommended for pain. In more severe case, a splint may be used to force the finger or thumb to remain at rest and cortisone treatments may be used. For those non responsive to conservative treatment, surgery may be necessary.