Trigger finger, medically known as stenosing tenosynovitis, is a medical condition in which a person has trouble straightening, or bending, her finger. In most cases there is a catch or a pop following movement from one finger posture to another, and in severe cases the finger is permanently bent. The condition may affect any finger and, in some cases, affects more than one finger on the same hand. It is more common in women than men and tends to affect people between ages forty and sixty. Treatment may include rest, splinting of the affected finger, pain and swelling relief medication, corticosteroid injection, and surgery.
The direct cause of trigger finger is the inability of the finger tendon to slide smoothly in its sheath. Finger muscles are located in the forearm and wrist and connected to points on the finger with long tendons. These tendons are encased in a sheath that keeps the tendon in its proper place. Either the tendon or the sheath may become inflamed, causing the tendon to rub against the inside of the sheath. There may be a loss of the lubricating fluid that fills the tendon sheath and normally enables the tendon to slide smoothly through it. In severe cases, lumps may develop on the tendon, and these lumps may catch on especially tight parts of the sheath. This resuilts in the characteristic catch-and-pop feeling when a lump passes a tight part of the sheath; in some cases the patient may feel as if her hand bones have fractured.
Like the vaguely similar carpal tunnel syndrome, trigger finger may be caused by diseases such as diabetes. Another common cause is rheumatoid arthritis. Sometimes overuse of the fingers is responsible. Trigger finger may also arise following sleep if the fingers have been inert for a period of time and have stiffened up. In most cases, however, the specific cause of trigger finger is not able to be determined. There appears to be no significant genetic factor beyond diabetes and arthritis propensities.
Mild cases of trigger finger may be treated with over-the-counter or prescription non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen. More severe cases may be treated with corticosteroid injections into the tendon sheath to reduce swelling. Severe cases may be treated with a surgical procedure in which the sheath is sliced open and then closed again, so that it heals together more loosely and there is more room for the tendon to move inside it. Because trigger finger is not a life-threatening condition and does not result in complications other than restricted hand use if untreated, treatment is usually a matter of personal choice. Surgery is usually performed outpatient and the patient is usually able to use their hand fully immediately following surgery, althoug it can take up to six months for the hand to heal fully.