What is polydactyly?

Polydactyly is an abnormality characterised by the development of extra digits in the hands and feet at birth. The condition is common in South Africa and affects approximately 1 in 500 births. Polydactyly is often hereditary, particularly along the maternal side, but can be linked to other genetic defects in rare cases.

Polydactyly can be divided into three major types, including ulna polydactyly, centralpolydactyly and radial polydactyly, which is dealt with under Thumb Duplications on this website.

Ulna or postaxial polydactyly in the most common form of polydactyly and is characterised by an extra finger on the side of the little finger. The extra finger may be a simple nubbin without any bones attached to the little finger or a fully formed digit. Central polydactyly, meanwhile, is much rarer and occurs when there is an extra middle or index finger formed on the hand.

In cases where the polydactyly can seriously affect the use of the hands, and even in some cosmetic cases, surgery is required to help improve the appearance and function of hands with polydactyly.

How is polydactyly treated?

When polydactyly occurs in the form of a nubbin, Dr Carter can surgically remove the extra finger with a simple elliptical incision. This is a day procedure and only takes 15 minutes. Dr Carter does not remove nubbins by tying sutures around them to restrict blood flow until they fall off because this can leave an unsightly residual piece of nubbin on the little finger, which often becomes irritating when a child starts to write.

When fully formed digits need to be removed surgically, Dr Carter will perform collateral ligament reconstruction to ensure that the child has full use of their affected fingers. Surgery for polydactyly is done when children are around a year old. This ensures they have a better chance of adapting to their reconstructed fingers.