Trigger finger, also called spring finger, is most common in older people but also occurs in infants. It usually turns out that the child can not stretch on the thumb. Occasionally the thumb will lock. This is because the bend tendon to the outer end of the thumb has thickened and hooks itself into the tendon.
The thickening disappears by itself in almost half of the children with trigger fingers and it is therefore possible to wait with surgery until the child is at least one year old. Even if the child has not been able to stretch the thumb in the outer joint for a year, the ability to stretch the thumb will always be normal after the procedure.