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In the process of making a father’s day card, 4 ½ year old Chelsea and her mother wanted to decorate the card with a print of her small hand. In the process, Chelsea’s mother realized that her daughter’s thumb seemed to be trapped in a bent position. Even with a gentle attempt to straighten the thumb it appeared to be stuck. Chelsea didn’t seem to have any pain so her mom wasn’t terribly alarmed but she made an appointment with her daughter’s doctor who diagnosed a trigger thumb and referred them to the pediatric hand surgeon at Rocky Mountain Hospital for Children.

What is a trigger thumb?

A trigger thumb either pops as it moves through its normal motion or becomes “latched” into a bent position.

Are trigger thumbs common?

Although it’s unclear how common this condition is, it is very frequently seen in the pediatric hand surgeon office. Perhaps as many as 2 percent of all hand problems in children are trigger thumbs. In many textbooks it’s called congenital trigger thumb hinting that it might have been present from birth, but in at least 99% of cases it presents later, between the ages of 18 months to 3 years. Very large studies involving thousands of children have shown only rare presentation at birth. It can be bilateral in 25 percent of the cases.

What causes trigger thumbs?

Research has shown no exact cause of trigger thumbs. In addition, there is no evidence showing a relationship between trigger thumbs and serious hereditary or congenital disorders. Normally, on the palm side of the thumb, there is a pulley which is a tunnel-like structure that controls the path of the tendon as the thumb moves up and down. Trigger thumbs are caused by a mismatch between the size of that tunnel and the tendon within it. This mismatch seems to occur during growth spurts of the hand. The tendon can no longer slide easily through the tunnel resulting in a swollen area within the tendon. This swollen area is called Nota’s node. Usually trigger thumbs, even when “latched”, are not painful except when Nota’s node is forced through the tunnel.

What are the symptoms of a trigger thumb?

  • Your child will have a flexed or bent thumb (in the “latched” position).
  • In the early stages your child may be able to completely straighten the thumb although there may be a click or pain with this motion.
  • Often a bump (Nota’s node) can felt at the base of the thumb in your child’s palm.

How are trigger thumbs diagnosed?

Your child’s doctor can diagnose this condition by conducting a thorough medical history and physical exam. Xrays are not needed because the bones are entirely normal.

How are trigger thumbs treated?

Newer research indicates that as many as 50 percent of trigger thumbs will resolve spontaneously by the time your child is 4 years old. Simple observation by the pediatric orthopedic team is recommended for children under the age of 4. In children who are over the age of 4 or for those who have significant pain surgery is recommended by a pediatric hand surgeon.

During surgery the dome of the tunnel is released to allow for more space for the tendon to glide. This is usually done using general anesthesia to limit the fear the child might experience. At the close of the procedure numbing medicine is injected, dissolvable sutures are placed and a protective cast is applied. Your child’s 10 day recovery is usually pain free.

What is the long-term outlook for my child?

Within 2-3 weeks of the surgery your child’s thumb motion will be normal with minimal chance for recurrence.

After her successful trigger thumb release, Chelsea was thrilled to present Dr. Benson with a thank you card decorated with her hand print. (picture)