Trigger Thumb - Children's Hospital Boston

300 Longwood Avenue
Boston, MA 02115
(617) 355-6000

My Child Has:

Trigger Thumb

Programs that treat this condition

Hand and Upper Extremity Program

Hand Clinic

What is a trigger thumb?

Trigger thumb refers to a thumb that clicks, catches, or locks as the tip of the thumb moves from a flexed (bent) to extended (straight) position. At times, the thumb may become "locked" in a flexed position.

What causes a trigger thumb?

Trigger thumbs are caused by a size mismatch between the flexor tendon of the thumb and the A1 pulley, a fibrous band under which the tendon normally glides. When the A1 pulley is too tight to allow for easy tendon gliding, the tendon can become swollen and inflamed, ultimately leading to triggering or inability to fully extend the thumb. Trigger thumbs occur sporadically and are not associated with other hereditary or congenital disorders.

How common are trigger thumbs?

The exact incidence of this condition is unknown. It is estimated that trigger thumbs comprise approximately 2% of all hand problems in growing children. While often referred to as "congenital" trigger thumbs, multiple studies of newborns indicate that this problem does not appear at birth. In approximately 30% of patients, there is bilateral involvement.

What are the symptoms of a trigger thumb?

Patients with trigger thumbs typically present with a flexed, or bent, thumb. Early on, the thumb can be extended, though often this is accompanied by pain, swelling, or a noticeable click. In the later stages, the thumb will remain in a flexed position. Often a palpable nodule, or bump, is felt at the base of the thumb in the palm.

How are trigger thumbs diagnosed?

Trigger thumbs are diagnosed by the treating physician after a thorough medical history and careful physical examination. X-rays are not used to make the diagnosis.

How are trigger thumbs treated?

Trigger thumbs may spontaneously resolve in a small percentage of patients, but the chances of this decrease with increasing age. For this reason, surgery is recommended for trigger thumbs in patients over the age of 1 year. Surgery involves releasing the A1 pulley overlying the flexor tendon. Patients are typically in a bulky soft bandage for 1 week. The risk of recurrent triggering following surgery is very small.



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