Polydactyly

Some children are born with extra fingers or toes, a congenital condition also known as polydactyly.

About polydactyly in kids

Polydactyly is a common physical abnormality in the hand that usually only affects one hand. Types of polydactyly include:

• Pre-axial polydactyly, also known as thumb duplication
• Post-axial polydactyly, the most common form, when an extra finger appears on the pinky side of the hand
• Central polydactyly, the rarest form, when the extra finger appears in the center of the hand

Extra fingers vary widely in appearance. The fingers might be joined or webbed, and often the extra finger is smaller or underdeveloped.

Experts in polydactyly

As the only comprehensive pediatric hand and upper extremity program in the state, Children’s Wisconsin provides expert care to kids and teens with a wide range of common and rare conditions affecting the shoulder, arm, elbow, wrist and hand. With our team’s specialized training, vast experience and deep knowledge of the unique challenges of children’s growing bodies, we can ensure the best possible outcomes for a child born with polydactyly. As Wisconsin’s highest-rated pediatric surgery center, our board-certified surgeons use the most advanced techniques and technology. Our child-centered environment and wraparound services are designed to support the whole family and provide comfort during treatment and beyond. If your child has already been diagnosed at another center, we invite you to get a second opinion at Children’s Wisconsin.

What causes polydactyly?

When a baby’s hands are developing in the womb, they start as a mitten shape and then grow into individual fingers. Sometimes an extra division occurs and develops into a partial or whole finger. Like other congenital defects, a baby’s anatomy can spontaneously develop abnormally with no known reason. Sometimes extra fingers and toes can run in families, and other times this condition is associated with genetic syndromes, such as Down syndrome.

Why is polydactyly a concern?

Most of the time, kids with this condition don’t have other health problems. However, most families opt to surgically remove the extra finger for cosmetic reasons as well as to maximize normal functional use of their child’s hand. An extra finger can affect a child’s daily life in multiple ways, from how they grip a pencil as they first learn to write to how well gloves fit their hands. For that reason, it’s usually recommended that the extra finger be removed early in childhood, before a child starts school.

How is polydactyly diagnosed?

Treatment for polydactyly

Treatment depends on the structure of your child’s hand. If your child has an extra pinky finger connected by only skin, the extra pinky can be clipped or tied off in a simple procedure at the doctor’s office. Like a baby’s umbilical cord stump, the extra pinky then falls off after about two weeks. Surgery is the recommended treatment in most cases with fully formed fingers or thumb duplication. This is usually done as an outpatient procedure when a child is ages 1-2. Our highly skilled pediatric hand surgeon will remove the extra finger and then rebuild the primary finger so that it is complete, repairing the bones, tendons and soft tissue in a precise and delicate manner to preserve your child’s movement and function. 

Hand therapy is a critical part of the postsurgical process to promote healing, increase range of motion and maximize functional use of your child’s hand. Our certified hand therapist offers serial casting, custom splinting, paraffin wax treatments, scar massage and more.

Long-term outlook for polydactyly

With proper treatment by a pediatric hand surgeon, most cases of extra fingers can be corrected and heal well. In more complex cases, a child might require more than one surgery to improve their hand’s appearance and/or function. Your child will need to continue to be monitored by a hand/upper extremity expert throughout early childhood to make sure their hand is developing and functioning appropriately.