Trigger Fingers in Children

Ninety percent of pediatric trigger digits are trigger thumbs. It is a rare condition affecting less than 0.05% of children. In children trigger thumbs do not trigger but remain locked in a flexed position. Palpation of a Notta’s node on the flexor pollicis longus tendon in the area of the thumb A-1 pulley is an important clinical sign differentiating a trigger thumb from other more severe clasped thumb anomalies. Controversy remains concerning the congenital versus acquired nature of pediatric trigger thumbs and the rate of spontaneous resolution. Most patients who present with a trigger thumb are older than 6 months of age.

The reported rate of spontaneous resolution of pediatric trigger thumbs has varied between 0% and 49%. There are multiple conflicting reports in which some documented a marked rate of spontaneous resolution, with other investigators noting that nearly all trigger thumbs persisted. The rate of successful conservative treatment is increased with splinting of the MCP joint in some studies.

Pediatric trigger thumbs respond predictably to a simple A-1 pulley release. A thumb with normal range of motion can be expected immediately after the procedure. McAdams et al ²⁷ investigated the long-term results of pediatric A-1 pulley release at an average of 15 years after surgery. There was no recurrence of triggering. Five of 21 patients had an average of 15° reduced interphalangeal joint motion and 4 of 21 patients showed MCP joint hyperextension; however, no patient complained of functional limitation. The most common concern was scar appearance, which was associated with a longitudinal instead of a transverse incision in the skin crease.

A delay in surgical intervention does not have adverse consequences. Multiple studies have documented good outcomes even in patients for whom surgical release was delayed up to 4 years after the onset of symptoms. Although the existing literature is far from conclusive, a trial of splint therapy is appropriate before performing an A-1 pulley release for pediatric trigger thumb.

Pediatric trigger finger is about one tenth as common as trigger thumb. ²⁸ Some patients present with a fixed flexion deformity. Similar to adult trigger digits, however, snapping and triggering is often the chief complaint. Cardon et al ²⁸ reported a high incidence of flexor tendon abnormalities in these children. In their series of 33 trigger fingers in 18 patients, 8 patients had continued triggering after A-1 pulley release. Documented abnormalities included a more proximal than normal decussation of the FDS, a slip of FDS that inserted into the FDP tendon, nodules in the tendon, and a stenotic A-3 pulley. These patients were treated with USSR, with 2 patients also having an A-3 pulley release. No patient had recurrence of triggering.