Thumb Hypoplasia and Aplasia | Diagnosis & Treatments

How is an underdeveloped or absent thumb diagnosed?

  • Thumb hypoplasia and aplasia are usually detected during your baby’s first newborn exam.
  • Seeing this deformity will prompt your child's doctor to look for other deformities that are sometimes associated with this condition.
  • An x-ray can help doctors examine the internal structures of your child’s thumb.
  • Other tests will depend on whether the doctor believes the thumb deformity is associated with another condition.

How is an underdeveloped or absent thumb treated?

Since the thumb is responsible for about half of a person's hand function, children born with underdeveloped thumbs need to be closely evaluated.

While most surgeons recommend an operation to correct the problem in cases where your child's hand's function is impaired, your feelings and attitudes about the procedures will be taken into account.

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.

Here's a general description of treatment options that your child's doctor will discuss with you:

  • Occupational therapy: If your child has a mild case of thumb hypoplasia in which the thumb is slightly shorter or the web space between the thumb and index finger is slightly tighter than normal, surgery may not be necessary and occupational therapy is recommended.
  • Reconstruction of the thumb: This may involve one operation to accomplish the following:
    • release the tight web space between the thumb and index finger using skin grafts
    • stabilize the middle joint through ligament reconstruction
    • improve function and stability by transferring a tendon from another part of the hand.
  • Pollicization: This procedure is used when your child has no thumb or when the hypoplasia is more severe. The operation involves creating a functional thumb by transferring another finger (usually the index) to the thumb position.

What's my child's long-term outlook?

After surgery (or occupational therapy in mild cases), your child's thumb should function very well.