To investigate the etiology, pathologic finding, main symptom, and ideal age for operative correction, trigger thumb in children, without any residual symptom and complications.

162 children (199 thumbs), who underwent operative treatment, formed the basis of this study. We investigate the main symptom, trauma history, other medical history, age of operation, relief of symptoms and complications after surgery. Two specimens were examined histolgically.

Only four (2.5%) thumbs demonstrated triggering at birth. All patients had flexion contracture of the interphalangeal joint of the thumb. There were nodules in 50 thumbs (25.3%) and triggering in 38 thumbs (19.2%). The average age at the time of surgery was forty months. All patients, had complete resolution of triggering after surgery and at the time of follow-up examinations, except for one patient who demonstrated a prominent wound scar. In the histological analysis, proliferation of fibroblasts and dense collagen material without inflammation and degeneration were characteristic findings.

Trigger thumb in children is a developmental condition caused by A1 pulley hypertrophy. The main symptom was flexion contracture. Therefore the term, developmental flexion contracture of the thumb, “rather than congenital trigger thumb,” is more appropriate. Surgical intervention is inexpensive, simple, safe and successful in preschool-aged children with persistent symptoms.