This blog explains all about the condition Trigger thumb, what it is and how it is managed.
What is trigger thumb?
Trigger Thumb is a condition seen in young children where the thumb gets stuck in a flexed (bent) position (see picture 1a and b) This occurs because the tendon that bends the thumb gets stuck in the tunnel it usually glides freely within. 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 (see red circle in pictures) Usually the thumb is able to be straightened to start with (hence the name trigger) but can become stuck . It occurs in both thumbs in about 30% of patients.
Picture 1a and 1b – clinical photograph of left trigger thumb in a 3 year old
What is the cause of trigger thumb?
We don’t know, but after screening thousands of newborn babies for the presence of a trigger thumb, we know it is not present at birth, but appears in the first 2 years of life. It is most likely a developmental problem where there is a mismatch between the size of the tendon and the tunnel it glides in.
What is the natural history of trigger thumb?
In infants younger than 9 months old, trigger thumb will resolve spontaneously in about 30% (1/3) of cases. So, in children presenting before this age, it is worth waiting to see if it does come straight on its own. Hand function is not specifically affected at this age. In thumbs that don’t resolve and stay flexed, then the joint can get start to get stiff and hence permanently stuck, which then may cause 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 next to the lump (see picture 3), the tight tunnel that the tendon glides in is carefully released. Care is needed to avoid the tiny nerves that supply the sensation to the tip of the thumb and also the blood vessels. We use dissolvable stitches and a non-sticky dressing with a crepe bandage that stays on for about 10 days. It is important to keep the dressing dry till review.
Picture 3 – preoperative picture
What is the aftercare?
At the follow up appointment, the wound will have healed and the scar is covered with a normal sticking plaster for a further week.
Picture 3 – At follow up appointment – thumb straight with no triggering.
Nev Davies and Richard Dodds are expert specialist Children’s Orthopaedic Consultants who have extensive knowledge of all orthopaedic conditions affecting children and young adults. They also have thriving adult knee practices treating all types of knee problems in patients of all ages, from ligament injuries through to arthritis.
They are the 2 consultants that make up the Reading Children’s Orthopaedic Unit. www.readingchildrensorthopaedicunit.co.uk
If you would like to meet them in clinic for an appointment about any orthopaedic problem, injury or niggle please contact their secretaries below.
If you are a GP, physiotherapist or sports therapist and would like us to come and talk to you about anything related to childrens’ orthopaedics or adult knee surgery for CPD, then please get in touch.
Nev Davies : Debbie Rollason on 07305 097 137 or e mail : firstname.lastname@example.org
Richard Dodds : Anne Gray on 08450941344 or e mail : email@example.com
They consult at all the main private hospitals in Reading as well in clinics in Henley-upon-Thames.