When the tip of the thumb is stuck in a flexed position, it’s called a trigger thumb. In this study researchers from Japan try to find out if children are born with this condition or if it develops as they get older.
The study was done over a four-year period. Over 1,100 babies (boys and girls) were examined during the first two weeks after birth. No one had a locked thumb. Parents were told what to look for and to report any signs of flexion deformity or trigger thumb. The parents agreed to check their children for up to one year.
The authors report two children developed trigger thumb in the first year. Three more children reported a trigger thumb at 15, 21, and 30 months after birth. The incidence of trigger thumb was 3.3 cases per 1,000 live births for this group.
The results of this study suggest that trigger thumb is not congenital. It develops as the child grows. Trigger thumb is likely present at an early age but parents don’t recognize or report it.
A delay in diagnosis often means surgery is needed to release the thumb. It’s possible that screening for trigger thumb and early treatment could solve the problem without surgery.