Congenital Trigger Thumb

Pediatric or congenital trigger thumb is essentially a stuck tendon and can occur in infants, toddlers, and young children. There is a tunnel at the base of the palm side of the thumb that the flexor tendon passes through. When the tendon gets thick, it cannot pass through the tunnel or does so with a “click” or “pop” that makes the end of the finger appear bent (see Figure 1). This condition gets its name from this bent finger, which looks like it’s cocking a gun.
Figure 1
Congenital trigger thumb presents as a thumb stuck in a bent position due to a thick tendon that either cannot pass through the tunnel at the base of the palm side of the thumb or can only pass through with a “click” or a “pop,” which might cause the child pain. Courtesy of Children’s Hospital Los Angeles

Causes

The cause of trigger thumb in children is not known. Trigger thumb is not seen in newborns, but it does seem to occur in up to 2% of the toddler-aged world population. Of those, nearly a third develop trigger thumb in both thumbs. Trigger thumb is not thought to be associated with a history of trauma. Some children just seem to have the anatomy or genetics to have it, and others don’t.

Signs and Symptoms

Potential signs and symptoms of trigger thumb include:

  • Inability to completely straighten the thumb
  • A “pop” or “click” of the thumb, which may make the child experience pain

Most children are without pain and use their hands normally, only with the thumb bent all the time.

Treatment

A detailed history of the child’s health including medical conditions, how the child is developing, “popping” or “clicking” in the thumb, pain, limited use of the thumb, family history, and prior injuries are important in diagnosing pediatric trigger thumb. In some cases (but not most) x-rays or ultrasound might be helpful.

The evidence suggests that nearly 80% of children will grow out of trigger thumb and not require more than observation. It is unknown if bracing or therapy can help the condition, and it’s unclear if the natural history of most trigger thumbs is to go away on their own.

When symptoms are severe or do not improve, surgery might be needed to make more room for the tendon to pass through the tunnel. Following surgery, soreness around the cut area can last for a week or two.

Recovery is typically fast and successful. The thickness in the tendon may not completely go away for several years, but the tendon will not get stuck, exhibit the “pop” or “click” sounds, cause pain, or remain bent.

Adults can get trigger thumb, too, but it has some different causes and treatments that may include rest, anti-inflammatory medications, and sometimes a steroid injection. The same surgery might help for different reasons. In children, however, there is no inflammation. It is a mechanical block from a thickened tendon, so no injections of steroids are indicated.

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