Trigger Thumb

What is trigger thumb?

Trigger thumb means your child’s thumb pops, clicks or catches when they try to straighten it. Their thumb may lock in a bent position. If the thumb locks, your child can pull it straight using their other hand. (Or you can pull it straight for them.) But they can’t straighten the locked thumb using their thumb muscles.

  • How does trigger thumb happen?

    The muscle that bends the tip of the thumb is called flexor pollicis longus (FLEX-er PAHL-i-sis LONG-us). This muscle starts in your child’s forearm. Near the wrist, the muscle turns into tendon. The tendon runs along the palm side of your child’s thumb and connects to the bone in the tip of the thumb.

    When your child moves their thumb, this tendon should glide smoothly inside a wrapping called a tendon sheath. Near the base of the thumb, a tough band (ligament) crosses the tendon and tendon sheath, acting like a pulley. Doctors call this the A1 pulley.

    Trigger thumb occurs when the tendon swells, forming a bump (nodule) near the A1 pulley. The nodule gets stuck at the pulley, so the tendon cannot glide inside the sheath. You may be able to feel this bump on your child’s palm at the base of their thumb.

  • Trigger thumb in children

    In children, trigger thumb usually happens between the ages of 1 and 3 years old. It’s not thought to be due to injury or other medical problems.

    Most children with trigger thumb have it in only 1 hand. About one-third of children have it in both hands. Triggering can happen in fingers, too. This is a different and more complex problem.

Trigger Thumb at Seattle Children’s

Trigger thumb is among the most common conditions treated by the experts in our Hand and Upper Extremity Program. Each year we see many children with this condition in our clinics.

Our team has a lot of experience treating trigger thumb. For many children, treatment begins with stretching and splinting. This may be enough to cure the problem. If it’s not, we perform surgery to release the A1 pulley. Our surgeons are experienced at performing this type of surgery in children.

We have the largest group of board-certified pediatric radiologists in the Northwest. Our radiologists have special expertise using ultrasound to look for bone and joint changes so we can work with your child to help prevent future problems. If your child needs imaging that uses radiation, we use the lowest amount possible to produce the best image. We also have a 3D low-dose radiation X-ray machine, called the EOS, for safer full-body 3D images.

Symptoms of Trigger Thumb

If your child has trigger thumb, they will have 1 or both of these symptoms:

  • Popping, clicking or catching when they move their thumb
  • Thumb locked in a bent position

Your child may also have these symptoms:

  • Pain and swelling in their thumb, usually near the base
  • Bump on the palm side of their thumb, near the base

Diagnosing Trigger Thumb

Doctors can diagnose trigger thumb by asking about your child’s symptoms and doing a physical exam.

If your child seems to have trigger thumb, the doctor will check to make sure they do not have some other problem, like a fractured bone or a joint that’s out of place (dislocated).

The doctor will also check for signs of broader health conditions that may affect the hands, like cerebral palsy or arthrogryposis. Most children with trigger thumb do not have any other condition.

Treatment Options for Trigger Thumb

Trigger thumb may get better on its own. Some children with trigger thumb need treatment so their thumb can move freely.

  • Stretching and splinting

    If the doctor believes stretching and splinting will be enough to cure your child’s trigger thumb, they will start with these options.

    They will teach you stretches and massage to do at home. This can help free the bump (nodule) from the tough band (ligament, A1 pulley) where it sticks.

    Your child may also need to wear a thumb splint to stretch their thumb and hold it straight. Because this prevents the thumb from moving, it may keep the A1 pulley from bothering the tendon. The swelling may decrease, and the tendon may glide the way it should.

  • Surgery

    If stretching and splinting aren’t enough, your child will need a day surgery called trigger thumb release or A1 pulley release.

    The surgeon makes a small cut (incision) on your child’s palm in the crease of skin at the base of the thumb. Then the surgeon cuts through the A1 pulley. This takes pressure off the tendon and allows it to glide smoothly. (The surgeon doesn’t cut into the tendon or remove the nodule.)

  • After surgery

    After surgery, your child will need a bandage for 1 to 2 weeks to protect their thumb while it heals. Trigger thumb rarely comes back, and children rarely need any other treatment for it. You can expect your child to regain typical use of their thumb.

Contact Us

Contact Orthopedics and Sports Medicine at 206-987-2109 for an appointment, a second opinion or more information.

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