Trigger Finger

Occasionally, parents will bring an infant or young child to the office complaining that their son or daughter cannot straighten out their finger. The thumb is the involved finger most of the time. The parents may go on to say that they can straighten the finger out but they feel a small pop when they do.

Trigger finger is a condition which is associated mostly with adults, but occasionally a child may be born with this condition. Often it is not noticed for some time by the parents. The thumb is the finger most likely involved in children.

The thumb or finger may occasionally lock in a flexed position. Often the digit can be straightened with help, but sometimes it remains flexed for a period of time. The thumb flexes at the IP joint, while the other fingers flex at the PIP joint.

In order to bend, each finger has a flexor tendon running along the palmar surface of the digit. When a flexor muscle in the forearm contracts, the tendon pulls on the tip of the finger, pulling it down. In order to keep the tendons sliding close to the bones of the finger, the tendon passes through several soft tissue tunnels, which are anchored to the bones, called pulleys. The pulleys are located at specific places along the digit and each has its own name. The pulley that caused triggering is the A1 pulley.

Triggering occurs when the pulley becomes inflamed or is congenitally thickened. When this happens, the tendon cannot slide easily thru the constricted pulley. The tendon becomes thickened itself, forming a nodule adjacent to the pulley. The pop one might feel undoing a trigger finger is the nodule passing thru the constricted pulley.

When seen in infants the trigger is observed for a time. Occasionally, the problem will correct spontaneously and no other treatment is needed. If the triggering persists, then treatment is indicated to prevent joint contracture. If the effected joint is flexed for too long then it will become stiff and not move well even if the triggering is resolved.

The treatment of trigger finger in children involves a small surgical procedure to open the pulley, allowing the tendon to slide freely thru it. In adults, a trigger finger can be treated initially with an injection if an anti-inflammatory medicine into the pulley. The medicine will increase the cross-sectional area of the pulley and decrease inflammation in the pulley which is sometimes all you need to do. If this fails, then surgical release is indicted.

To release a trigger thumb a small incision is made in the skin crease at the base of the thumb. Care must be taken to avoid damaging small sensory nerves to the thumb which pass near the incision site. The bandage from the surgery is left on for ten days to allow the skin to heal. There is a very small chance that the triggering can recur in the future.