Conditions Treated

Thumb hypoplasia

Thumb hypoplasia means that your child’s thumb is unusually small or underdeveloped. Severity ranges from a thumb that is slightly smaller with normal structures through varying degrees of bone, tendon, ligament, muscle and joint underdevelopment to complete absence of the thumb.

Thumb Hypoplasia.

Drawing by Luke, age 13

What causes an underdeveloped or absent thumb?

The exact cause of the condition remains unknown.

How common is an underdeveloped or absent thumb?

It’s rare, occurring in about 1 out of every 100,000 babies. It can occur by itself or may be associated with other conditions such as radial club hand in which the inner (radial) aspect of the forearm, wrist and hand do not develop properly. It can be associated with medical conditions such as Holt-Oram syndrome and Fanconi’s anaemia.

How is an underdeveloped or absent thumb diagnosed?

Thumb hypoplasia and aplasia are usually detected during your baby’s first newborn examination. X-rays are used to examine how the underlying bones are affected. In addition it is important for your child to be evaluated for other deformities that are sometimes associated with this condition. Other scans and tests may be required in this regard.

How is an underdeveloped or absent thumb treated?

Treatment programs are always individualised to meet the needs of your child. If there are no other pressing medical concerns that need to be addressed, surgery is generally performed when your child is between 6 and 18 months old. There are a variety of different options that can be used:


If your child has a mild case of thumb hypoplasia surgery may not be necessary and physiotherapy with one of our specialist hand therapists is recommended.

Reconstruction of the thumb

This involves an operation to release the tight web space between the thumb and index finger. This may require the use of skin grafts. In addition as part of the procedure the middle thumb joint may need to be stabilised and a tendon transfer may be carried from another part of the hand to improve function and stability.


This procedure is used when your child has a severely underdeveloped thumb or no thumb at all. The operation involves creating a functional thumb by transferring another finger (usually the index) to the thumb position. This operation has an excellent track record and its results are reliable.

Decisions regarding treatment are made very carefully and are always aimed at improving your child’s overall hand function. You will be involved in every decision that is made in the care of your child.

What’s my child’s long-term outlook?

After surgery (or physiotherapy in mild cases), your child’s thumb should function very well. Long-term follow-up is required to ensure that healing is going well and function is optimised. We will organise for your child to see one of our specialist hand therapists who will help reduce scarring, swelling and stiffness and improve strength. We will continue to follow-up your child as they grow to ensure that they are adapting and functioning well.



To book an appointment with Mr Sivakumar or for more information please call 020 7432 8329 or email

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