Trigger thumb in infants and young children occurs because of a size mismatch between the tendon and the tendon sheath that surrounds it. This can cause the thumb to be stuck in a bent position.
Key points
Trigger thumb refers to a thumb that catches or gets stuck in a bent position.
Some children can bend and straighten the thumb, however straightening can cause a clicking sensation caused by the tendon popping in and out of the tendon sheath. This can feel painful.
Trigger thumb is very common in children and, in a small percentage of children, can resolve on its own. However, many children will require surgical treatment.
Diagnosis involves a physical examination.
Introduction
What is a trigger thumb?
The thumb bends and straightens with the help of cords of tissue called tendons. Tendons connect muscle to bone and allow them to move together. Tendons in your thumb help it to bend and straighten. Tendons travel in a tunnel, called the tendon sheath. The entrance to the tunnel (called the A1 pulley) lies at the base of the thumb. If the tendon is too big or the tunnel too small, the tendon can get stuck at the entrance to the tunnel, resulting in a trigger thumb.
Normal thumb
Often a bump, or nodule can be felt where the tendon gets stuck at the entrance to the tendon sheath. Most commonly, the thumb gets stuck in a bent position. Trigger thumb is very common in children and is easily treated.
Trigger thumb
Signs and symptoms
Symptoms of trigger thumb
The most common symptom of trigger thumb is when the thumb is permanently stuck in a bent position. Children are generally unable to give a “thumbs up” when they have a trigger thumb.
Trigger thumb can also present when a child has difficulty straightening their thumb. The thumb may feel stiff but can straighten with help. Manual straightening of the thumb can feel tight and painful, causing swelling or a clicking sound.
Causes, risk factors and prevalence
Causes of trigger thumb
Pediatric trigger thumb occurs by chance, and it is very common in children. In about half of children with trigger thumb, both thumbs are involved.
Diagnosis
Diagnosis of trigger thumb
Trigger thumb is diagnosed by doing a physical exam. A plastic surgeon will complete an assessment to confirm the trigger thumb diagnosis. Your child will not need X-rays unless the diagnosis is a condition other than trigger thumb. The assessment is usually done when your child is as close to 3 years of age as possible.
Treatment
Treatment of trigger thumb
In a small percentage of children with trigger thumb, the condition can resolve on its own. If the trigger thumb has not resolved on its own by the time the child is about 3 years of age, the finger remains in a bent position and the child cannot manually extend the thumb, then surgery is recommended to correct the condition. See the article on
trigger thumb treatment for more information.
At SickKids
At SickKids
The Plastic Surgery Clinic is located on the Main floor, in the Black wing, Room M465 near Shoppers Drug Mart.
Your child will come to the Plastic Surgery Clinic for their appointment. Please check in at the Registration desk on arrival. It is helpful if you read this information before your appointment and come prepared with questions. We look forward to seeing you!
