trigger finger

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Trigger Finger

 

Definition

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).

Description

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.

Diagnosis

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.

Treatment

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 may take up to four weeks. Sometimes physical therapy of the hand is required after surgery to regain good use.

Alternative treatment

Treatment should begin when a person starts having difficulty moving the fingers. If started early, non-invasive 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.

Prognosis

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.

Prevention

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.

Resources

Periodicals

"Ask the Mayo Physician." Health Oasis Mayo Clinic May 4, 2000.
Phillips, D. F. "New Paradigms Sought to Explain Occupational and Environmental Disease." JAMA January 6, 1999.
Stroud, R. "Minimally Invasive Surgical Techniques of the Hand and Upper Extremities." Orthopedic Technology Review September2000: 18.

Organizations

American Society for Surgery of the Hand. 6300 N. River Rd., Suite 600, Rosemont, IL 60018. 〈http://www.hand-surg.org〉.

Other

Jameson DC, CCSP, Timothy J. "Explanation,Treatment,and Prevention of Trigger Finger."GuitarBase Articles. 〈http://www.gbase.com/articles/med/med4.html〉.

Key terms

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.

trig·ger fin·ger

a condition in which the movement of the finger is arrested for a moment in flexion or extension and then continues with a jerk; results from localized swelling of the tendon that interferes with its gliding through the pulleys in the palm of the hand.

trigger finger

a phenomenon in which the movement of a finger is halted momentarily in flexion or extension and then continues with a jerk. Also called jerk finger.
enlarge picture
Trigger finger, locked position
A digit with a focal fusiform swelling—due to oedema and/or inflammation—of the flexor tendon or tendon sheath which causes a painful lock-snap sensation, leaving the digit in flexion or extension. Trigger finger is most common in women in their sixth decade, and is associated with de Quervain’s disease, carpal tunnel syndrome, tenosynovitis, rheumatoid arthritis, and connective tissue disease
Trigger finger in children Idiopathic, linked to chromosome defects, secondary to fractures, tendinous or ligamentous lesions

trigger finger

Tenosynovitis Rheumatology A digit in which the flexor tendon passes through a fibro-osseous tunnel, in which there is a fusiform swelling–congenital, edema or tenosynovitis of the tendon or tendon sheath causing a painful lock-snap sensation, leaving the finger or thumb in flexion or extension; TF is most common in ♀ in the 6th decade, and associated with de Quervain's disease, carpal tunnel syndrome, rheumatoid arthritis, and collagen vascular disease; TFs in children may be idiopathic or linked to chromosome defects; trigger/locked fingers may be caused by various fractures, tendinous or ligamentous lesions

trig·ger fin·ger

(trig'ĕr fing'gĕr)
Condition by which the finger flexors contract but are unable to reextend due to a nodule within the tendon sheath or sheath constriction.

trigger finger

An effect of a localized swelling in the tendon that bends a finger. The flexor tendon runs partially in a fibrous sheath and although the swelling can easily slip out of the end of the sheath, when the finger is bent, it cannot easily slip back in again. As a result, the finger remains bent until straightened passively, often with an audible click. Treatment is by opening the sheath surgically.

trigger finger

a condition in which the finger can be actively bent but cannot be straightened without help; usually due to tenosynovitis of the flexor tendon sheath resulting in thickening or nodules which prevent free gliding. Seen particularly in gripping sports such as climbing. Treatment is by local corticosteroid injection or surgical release.