Pediatric trigger thumb is a relatively common condition in young children, occurring in about three out of every 1,000 children by one year of age. It is a mechanical issue where the thumb’s movement is restricted, often resulting in the digit being stuck in a bent or flexed position. Although it can look alarming, it is a localized issue of the hand.
The Primary Symptom and Pain Level
A primary concern for parents is whether pediatric trigger thumb causes pain. The condition is typically painless, especially when the thumb is fixed in the bent position. The main symptom is mechanical restriction, where the thumb cannot fully straighten on its own, usually becoming noticeable between the ages of one and four.
If pain occurs, it is generally mild discomfort or tenderness located at the base of the thumb. This sensation usually happens when the locked thumb is passively extended against the obstruction. The characteristic clicking or popping sensation is called “triggering,” which occurs when the tendon is momentarily caught and then released. A small lump, called Notta’s nodule, is often palpable at the base of the thumb, moving with the tendon.
How Pediatric Trigger Thumb Develops
The condition results from a size mismatch between the thumb’s flexor tendon and the tunnel it runs through. The flexor pollicis longus (FPL) tendon, which bends the tip of the thumb, travels inside a protective sheath secured by fibrous bands called pulleys. The A1 pulley, located at the base of the thumb, is the most significant of these bands.
In pediatric trigger thumb, the FPL tendon develops a localized thickening, forming the Notta’s nodule. This swollen section is too large to slide smoothly through the tight opening of the A1 pulley. When the child attempts to straighten the thumb, the nodule catches on the pulley, causing the digit to lock in flexion or suddenly pop through the constriction.
Diagnosis and Natural History
Diagnosis is made through a simple clinical examination based on the presence of a locked thumb and a palpable Notta’s nodule. Imaging, such as X-rays, is not required unless a doctor suspects another issue, such as a fracture. The condition is considered developmental, as it rarely manifests at birth and typically appears later in infancy or early childhood.
The natural history of this condition is favorable, as many cases resolve spontaneously without intervention. Studies indicate that 60% to 75% of cases correct themselves over time, though this process can take several years. This high rate of spontaneous resolution supports an initial “wait-and-see” approach for younger children. Parents should still consult a physician to confirm the diagnosis and establish a monitoring schedule.
Treatment Pathways
Management is divided into observation and active intervention. For children younger than two years old, the initial approach is non-surgical observation, relying on the high probability of spontaneous resolution. Passive stretching exercises or splinting may be recommended, but these methods do not consistently increase the rate of resolution.
If the condition has not resolved by around two years of age, surgical intervention is recommended. The operation is a simple, highly effective procedure performed under general anesthesia. It involves a small incision at the base of the thumb to release the A1 pulley. This release widens the tight tunnel, allowing the flexor tendon and its nodule to glide freely.
Surgical release is considered the definitive treatment, boasting a success rate exceeding 95%. During the procedure, care is taken to preserve structures like the radial digital nerve and avoid cutting the oblique pulley to prevent tendon bowstringing. Following the operation, the child typically regains full, unrestricted movement of the thumb.