Trigger finger is the popular name of stenosing tenosynovitis, a painful condition in which a finger or thumb locks when it is bent (flexed) or straightened (extended).
Tendons are tough, fibrous cords that connect muscles to bones. Tendons must slide easily through their protective coverings (tendon sheaths). The finger and thumb bones have tendons that are responsible for bending and straightening the fingers. Problems start when a tendon sheath narrows (stenosis) and the outer covering of the tendon becomes inflamed (tenosynovitis). The tendon swells because of the constriction, sometimes forming a nodule, and is no longer able to move smoothly through its sheath. As a result, a finger may lock in an upward position as the person tries to straighten it. The condition usually happens in the ring and middle fingers and is more common in women, typically over age 30. In infants and small children, the condition generally occurs in the thumb.
Causes and symptoms
Trigger finger is often an overuse injury because of repetitive or frequent movement of the fingers. Trigger finger may happen because a person performs the same manipulation over and over on a job, from squeezing and gripping during a weekend of heavy pruning and gardening, or from such hobbies as playing a musical instrument or crocheting. Trigger finger may also result from trauma or accident. The symptoms of trigger finger are pain in the fingers and "popping" sensations. Sometimes the finger may lock down into the palm or lock out straight. Symptoms are usually worse in the morning and improve during the day.
The diagnosis of trigger finger and thumb is obvious on physical examination. Often there is a click that can be felt as the nodule passes through the sheath. Most cases are uncomplicated although X rays are often taken to rule out other injuries or disease such as arthritis.
Initial treatment for mild or infrequent symptoms of trigger finger include rest, avoiding or modifying those activities that caused the inflammation, and the use of a nonsteroidal anti-inflammatory drug (NSAID) such as ibuprofen. This may relieve the swelling and inflammation that resulted in the constriction of the sheath and the restriction of the tendon. Injection of a steroid medication (cortisone) into the tendon sheath is the next option to treat trigger finger. Depending on the severity, there may be one more injection a week later. Two-thirds of patients improve after one injection. Some physicians will splint the finger in extension after the injection.
In severe cases that do not respond to injections and the finger or thumb remains in a locked position, surgery may be required to relieve the symptoms. A local anesthetic is used for the surgical procedure performed on an outpatient basis. An incision is made by a surgeon in the palm of the hand at the base of the affected finger or thumb to relieve the constriction of the tendon. Recovery
Treatment should begin when a person starts having difficulty moving the fingers. If started early, noninvasive measures have a good chance for success. Alternative treatments include acupuncture to facilitate healing and microcirculation, pulsed ultrasound, and myofascial release work for the affected area.
At least half of cases can be cured non-surgically. The key to successful treatment is early intervention. A mistake people make is trying to work through the pain. Diabetics have a higher incidence of the condition and are sometimes left with a disability.
Taking frequent breaks from a repetitive activity will do much to prevent the condition. Depending on the intensity, that may mean a 10 minute break every hour from the repetitive activity. The break should be spent stretching the hands and arms and generally moving around.
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American Society for Surgery of the Hand. 6300 N. River Rd., Suite 600, Rosemont, IL 60018. <http://www.hand-surg.org>.
Jameson DC, CCSP, Timothy J. "Explanation, Treatment, and Prevention of Trigger Finger."GuitarBase Articles. <http://www.gbase.com/articles/med/med4.html>.
Microcirculation—The passage of blood in the smallest blood vessels of the body, such as the capillaries in the hand and fingers.
Myofascial—The fibrous tissue that encloses and separates layers of muscles.
Nodule—A swelling or knob that may form on a tendon and make it difficult to slide smoothly through its sheath.
Stenosis—Narrowing of a passageway or opening in the body. In trigger finger it is the tendon sheath that narrows.
Synovial tendon sheath—Where the tendons cross joints, they are sheathed in thin membranes known as synovium, which provide lubrication to decrease friction.
Tendon sheath—A membrane covering a tendon.
Tenosynovitis—Inflammation of a tendon and its enveloping sheath, usually resulting from overuse injury.