Syndactyly

Some children are born with fused or webbed fingers or toes , a congenital condition also known as syndactyly.

About syndactyly in kids

This common hand abnormality affects 1 in 2,000-3,000 children   and is twice as likely to occur in boys than in girls. Syndactyly can be complete, when the fingers are fused along the full finger length, or incomplete, when the fingers are fused only partially. Cases are also classified as:

• Simple syndactyly – when the fingers are connected by only skin and soft tissue, which is the most common situation
• Complex syndactyly – a rare condition in which the finger bones are also fused together 

This condition usually affects the three middle fingers (index, middle and ring finger), though it can also affect the thumb and pinky. Kids may have fused fingers on one or both hands.

Experts in syndactyly

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 syndactyly. 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 syndactyly?

When a baby’s hands are developing in the womb, they start as a mitten shape and then develop into individual fingers around weeks 6-8. When this normal division fails to occur, it causes a baby’s fingers to grow in a webbed-like manner. Like other congenital defects, a baby’s hand anatomy can spontaneously develop abnormally with no known reason. In as many as 40% of cases , fused fingers and/or toes run in families. Syndactyly is also sometimes associated with genetic syndromes, such as Apert, Poland and Carpenter syndromes.

Why is syndactyly a concern?

Most of the time, kids with this condition don’t have other health problems. However, most families opt to surgically separate the fingers for cosmetic reasons as well as to maximize normal functional use of their child’s hand. If left untreated, syndactyl can affect a child’s hand function and dexterity and lead to worse hand deformities as a child grows. Fused fingers 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 fused fingers be corrected early in childhood, when kids are working on critical fine and gross motor skills.

How is syndactyly diagnosed?

The doctor might spot a baby’s hand abnormality on a prenatal ultrasound, but often, this condition is discovered at birth. To determine the best course of treatment, our hand/upper extremity specialists will evaluate your child’s hand structure and possibly take an x-ray. At Children’s Wisconsin, we use imaging procedures that ensure your child is exposed to the smallest amount of radiation possible.  

Your child’s doctor might also recommend genetic testing to see if the syndactyly is related to a syndrome that could cause other problems.

Treatment for syndactyly

Treatment depends on the structure of your child’s hand. Surgery is the recommended treatment in most cases. Our highly skilled pediatric hand surgeon will separate the fingers and, if necessary, rebuild both fingers so that they are complete, repairing the bones, tendons and soft tissue in a precise and delicate manner to preserve your child’s movement and function in the future. The surgeon might need to take some skin from another part of the body (such as the elbow or wrist crease) to cover the newly separated fingers.

With cases involving the middle fingers, this procedure is usually done when a child is between ages 1-2. With cases involving the thumb or pinky, where those shorter fingers are fused to a longer finger, surgery is usually done before age 1 to allow for more normal hand growth and development. Complex syndactyly is usually corrected before age 1 as well.

After surgery, your child will need to wear a cast for 3-4 weeks (typically) to immobilize and protect their hand while it heals. Some children may see a hand therapist after surgery

Long-term outlook for syndactyly

With proper treatment by a pediatric orthopedic surgeon, most cases of fused fingers can be corrected and heal well. Sometimes scar tissue develops between the fingers, creating what’s known as “web creep.” In that situation and in other 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.