Did you know that polydactyly is one of the most common congenital conditions of the hands and toes? About 1 in every 1,000 babies is born with extra digits. At Cook Children's our orthopedists will discuss options with you and create and individualized plan that you and your child are comfortable with.
Polydactyly is when a baby is born with an extra finger on the hand or an extra toe on the foot. It can be on one or both hands or feet.
Polydactyly usually happens on the pinky finger side of the hand or little toe side of the foot (called "post-axial"). Less often, it happens on the thumb or big toe side ("pre-axial"). Rarely, it can be central or in the middle of the hand or foot. The extra digit is usually smaller than the other fingers or toes.
Polydactyly happens before a baby is born. When a baby's hands and feet are first forming, they're shaped like mittens. Then the fingers or toes form. If an extra finger or toe forms, this causes polydactyly.
Genetics are the most common cause of polydactyly. However, environmental factors may also play a role. This may be due to:
- The mother having diabetes
- Low birth weight
- An upper respiration tract infection in the mother during the first three months of pregnancy
- A history of epilepsy in the mother
Any baby can be born with polydactyly. Post-axial polydactyly can run in families.Most babies who have polydactyly do not have other health problems. But sometimes, it happens as part of a genetic syndrome.
Polydactyly occurs in 1 in 1,000 births in the overall population, but occurs more often in African Americans with 1 in 150 births. It's also more common in boys than girls.
It is most often seen in the right hand and left foot, and typically affects the hands.
Polydactyly may be seen before birth on an ultrasound. Otherwise, doctors diagnose it when the baby is born.
Sometimes doctors do X-rays to see if the extra digit has bones and joints. This helps the surgeon decide what kind of treatment is needed.
Treatment for polydactyly depends on the location of the digit on the hand or foot and how it is formed. An extra pinky or little toe that is connected with a thin stalk can be removed easily, sometimes right in the surgeon's office with a surgical clip or stitch.
Extra thumbs, big toes, or middle fingers or toes that contain bones and/or joints need surgery in the hospital.