Polydactyly (Extra Toe on Foot)

Polydactyly is one of the most common hereditary limb malformations
featuring additional digits in hands and/or feet.

Causes and Treatment of Polydactyly of the Foot

What Is Polydactyly?

Polydactyly is a congenital variation in the foot that causes an extra toe to grow. It may also occur in the hand, where an extra finger grows. The name derives from the word poly, meaning many, and dactyl, meaning digit.

The location of the extra digit determines its classification:

  • Preaxial polydactyly is toward the first digit
  • Central polydactyly, as the name implies, is in the center
  • Postaxial polydactyly is most common and is duplication of the fifth digit

"Polydactyly may be obvious, with the formation of a completely separate digit, or it may be less obvious, as the digit is merging with another, giving the appearance of a larger than normal toe."

Bottom view of a child's foot with polydactyly "non-merged"
Bottom view of a child's foot with polydactyly "non-merged"
Bottom view of child's foot with polydactyly "merged"
Bottom view of a child's foot with polydactyly "merged"

What Causes Polydactyly?

Your child may develop polydactyly even when no other foot dysfunction is present. It is a genetic condition that may run in the family, but your child’s condition may also be an isolated incident.

Polydactyly may also occur as part of a syndrome, such as Greig cephalopolysyndactyly syndrome, which affects the limbs, head, and face; or Bardet-Biedl syndrome, which impacts multiple systems in the body. Both of these syndromes are rare genetic disorders.

How Is Polydactyly Diagnosed?

X-rays are necessary to see what’s happening under the skin and determine the exact nature of your child’s polydactyl condition. At Pediatric Foot & Ankle, we start by performing a digital x-ray, which helps determine the type of polydactyly your child has and set expectations regarding treatment.

Below is an x-ray of a child’s foot with polydactyly that is merged.

Polydactyly merged xray
X-ray of a child's foot with Polydactyly
X-ray of a child's foot with Polydactyly

How Is Polydactyly Treated?

There are two options to treat polydactyly: conservative and surgical.

As the condition is not painful, the main issue with conservative treatment is finding accommodative shoe gear. There is also the emotional toll of polydactyly, which can be stressful for the parent.

The only real cure for polydactyly is surgical intervention. Dr. Jarman points out that there is “no true consensus on the recommended age of surgical intervention.” He typically recommends removing the extra digit once the child reaches 1 to 2 years of age. By this time, the “bone structure has matured and will allow for a more successful cosmetic outcome.”

Attempting to remove the extra digit too early may result in an incomplete removal of the malformed tissue. This is why presurgical planning must be carefully based off of x-rays and the child’s unique foot structure to ensure the best outcome. With proper planning, though, the long-term outcome is excellent.

Child with Polydactyly top view of foot
Child with Polydactyly side view of foot

What to Expect from Polydactyly Surgery

Removing the extra digit on your child’s foot is an outpatient procedure. Children rarely require an overnight hospital stay following surgery.

Pre- and postsurgical instructions vary according to the type of polydactyly your child experiences (postaxial, preaxial, or central), and whether the removal involves bone or only soft tissue. Always follow Dr. Jarman’s instructions exactly to the best outcome.

Polydactyly extra toe on foot pre-surgical
Polydactyly "extra toe on foot" pre-surgical
Polydactyly extra toe on foot post-surgical
Polydactyly "extra toe on foot" post-surgical

Your child’s feet are designed for life