Information for Families – Trigger Thumb
What is trigger thumb?
Trigger Thumb is a condition seen in young children where the thumb gets stuck in a bent position (flexed) see picture. This occurs because the tendon that bends the thumb gets stuck in the tunnel it usually glides freely in. If you feel carefully at the base of the thumb you can feel the rucked up tendon as a nodule (it’s the size of a pea) Usually the thumb is able to be straightened to start with but can become fixed. It occurs in both thumbs in about 30% of patients.
What is the cause?
We don’t know, but after screening thousands of newborn babies we know it is not present at birth but appears in the first 2 years of life.
What is the natural history?
In infants younger than 9 months old, trigger thumb will resolve spontaneously in about 30% (1/3) of cases. In thumbs that don’t resolve and stay flexed, then the joint can get very stiff and also stuck, causing functional problems later in life.
What is the treatment?
We always watch and wait for a few months to see if the triggering resolves by itself. If after 3 months the thumb is still triggering or stuck down, then surgery is the next step. This is done as a day case under a general anaesthetic.
What is involved with the operation?
Through a small horizontal skin crease incision over the lump, the tight tunnel that the tendon glides in is released. Care is needed to avoid the tiny nerves that supply the sensation to the tip of the thumb. We use dissolvable stitches and a non-sticky dressing with a crepe bandage that stays on for 2 weeks. The nursing staff will give you instructions regarding dressing care, and your follow up appointment.