What is Thumb Hypoplasia and Aplasia?
Thumb hypoplasia means that your child’s thumb is unusually small or underdeveloped. Additionally, the bones and the muscles that move the thumb are involved. This condition is also commonly called hypoplastic thumb.
Thumb aplasia means that your child’s thumb is missing altogether.
What causes a child’s thumb to be underdeveloped or missing?
The cause of this condition is unknown. However, it often happens together with radial longitudinal deficiency. It can also happen in association with the following syndromes:
- Holt-Oram syndrome
- Fanconi syndrome
- VACTERL sequence.
How are Thumb Hypoplasia and Aplasia treated?
The decision about whether or not thumb hypoplasia or aplasia should be treated is not always straightforward. Children adapt and can function with a missing finger. If untreated, children who have no use of a thumb can learn to pinch objects using their long and index fingers. But they may have problems with pinch strength as well as activities that require holding larger objects. Surgery for thumb hypoplasia is designed to help with these functional issues and with appearance.
Thumb reconstruction surgery
This surgery reconstructs the ligaments in the thumb to stabilize the middle joint and improve function and stability by transferring a tendon from another part of the hand. It may also involve an operation to release the tight web space between the thumb and index finger using a skin graft.
Thumb reconstruction can be done when your child is 1 year old or up through when they are school-age.