Syndactyly

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Four photos of children’s hands with webbed skin between fingers From left to right: Webbed skin between fingers or toes is a common feature of syndactyly. Fingers or toes may be joined all the way from the base to the tip or only partway up.

What is syndactyly?

Having fingers or toes that are joined is called syndactyly (sin-DAK-til-ee). In most cases, the are joined side by side only by skin or other soft tissue, which may look webbed. The fingernails or toenails may also be joined.

Sometimes the digits are joined at the bone. There may be other problems with the (fah-LAN-jeez) in the joined digits, such as extra, missing or misshaped bones. The digits may share connections between their muscles, , nerves and blood vessels, too.

It is possible that 2, 3, 4 or all 5 digits on a hand or foot may be joined. The joined section may go only partway from the base of the fingers or toes to the tip (partial or incomplete syndactyly) or all the way from the base to the tip (complete syndactyly).

Many babies with syndactyly have no other differences in their bodies and no health problems. But this condition can happen along with other hand or foot conditions, such as polydactyly (then it’s called polysyndactyly) or with other conditions or other syndromes, such as Apert syndrome.

How common is syndactyly?

This is a fairly common condition. It happens in about 1 in 2,000 to 1 in 3,000 babies. It’s passed down in some families (inherited). Often it happens to only 1 person in a family because of changes in their .

About half of babies born with syndactyly have it on only 1 hand or foot. About half have it on both hands or feet.

What causes syndactyly?

When a baby’s hands and feet begin to form, they are shaped like mittens or paddles. Then the fingers and toes divide. In most babies with syndactyly, the fingers or toes did not divide all the way. In babies with amniotic band syndrome, the fingers or toes may have divided and then joined again as they healed after injury (acrosyndactyly).

Orthopedics and Sports Medicine at Seattle Children's

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What are the symptoms of syndactyly?

Children with syndactyly are born with 2 or more fingers or toes that are joined. The joined digits may look webbed, and they may not move well.

For some children, syndactyly is only 1 feature of a more complex genetic condition or other syndrome. These children will have other signs and symptoms.

How is syndactyly diagnosed?

If your child is born with joined fingers or toes, the doctor will examine your child carefully. During the exam, the doctor will check for other signs to tell whether your child has a more complex condition.

Your child may need an to see whether the phalanges are joined or only the skin and soft tissues are joined. If the doctor thinks your child might have a more complex condition linked with syndactyly, your child may have other tests.

How is syndactyly treated?

Joined toes rarely need treatment because they rarely cause any problems with a child's function. If syndactyly makes your child’s toes grow at an angle that’s not typical, your child may need surgery to divide the toes.

Doctors almost always do surgery to divide joined fingers in early childhood. The goal is to give your child hands that work well and look typical. In rare cases, doctors leave 2 fingers joined. Your child’s doctor may recommend this if the digits work well as a unit but are not likely to work apart because they share nerves, blood vessels and tendons.

Surgery for Syndactyly

Dividing digits

If only 2 digits are joined and they are joined only by skin, the surgery will be simpler. If more digits are joined or the digits are joined at the bone, the surgery will be more complex. In any case, it is often done as .

The basic method for the surgery is to make zigzag cuts (incisions) between the digits to divide them. The zigzag shape gives the surgeon pointed flaps of skin to wrap around each digit. This method helps prevent scars that could restrict growth later.

Near the base of the digits, the surgeon cuts another flap of skin that gets folded over to make a typical web between the digits. The surgeon sews all the flaps in place.

Skin grafts

Most children need skin grafts to cover the digits completely after they are divided. The zigzag method reduces the need for skin grafts. But sometimes the flaps are not big enough. The surgeon takes a small patch of skin, usually from the child’s forearm, to close up the area around the digits.

After surgery

After surgery, your child will need to wear a cast. The doctor will want your child to come back for follow-up visits to make sure they are healing well. At a follow-up visit, we will remove the cast, and an occupational therapist will fit your child with a splint. This helps prevent scarring and shortening of tissue (contractures). Some children who have extensive surgery, cutting through many tissues, may have occupational therapy to help with swelling, scarring and stiffness.

Surgery timing

The timing of surgery varies. Your child’s team will work with you to make a plan based on your child’s needs.

In general, we do surgery earlier for digits joined in a more complex way. This can prevent problems that might happen as your child grows. A digit that is joined to its neighbor may grow at an angle or become twisted because the digits grow at different rates.

In most cases, surgeons divide the thumb from the first finger and the ring finger from the little finger around the age of 6 months. If any of the middle 3 fingers are joined, surgeons usually divide them after the age of 1 year.

If your child has 3 or more joined digits, they will need more than 1 surgery. The surgeon will work on only 1 side of a digit, not both sides, during 1 surgery. This reduces the risk for problems with blood flow to the digit.

Why choose Seattle Children’s for syndactyly treatment?

Seattle Children’s Hand and Upper Extremity Program treats children with syndactyly. Each year we see many babies with this condition in our clinics. Our team is experienced in the range of treatment options for syndactyly. We create a treatment plan custom-made for your child to get the best results for them.

The hand and foot experts you need are here
- Your child’s team includes doctors, surgeons, and nurses from Orthopedics and Sports Medicine as well as Plastic Surgery if needed.
- For many of our patients, treatment means surgery — sometimes highly complex surgery — to divide digits. Our surgeons are experienced at doing this type of surgery in children. We have surgeons with expanded fellowship training in upper extremity surgery and foot and ankle conditions.
- If your child needs occupational therapy after surgery to gain the best use of their hands or feet, we have the largest team of occupational therapists in the Pacific Northwest who specialize in the care of babies, children, teens and young adults.
Care from before birth through young adulthood
- We specialize in caring for kids. This means our experts have the knowledge, training and skills to treat the youngest patients, including babies and young children with joined digits. At Seattle Children’s, your child’s team has special training in the medical, surgical, emotional and social needs of young people.
- If your child is diagnosed with syndactyly before birth based on an , we offer prenatal consultations to talk with you about your baby’s condition.
- Babies and children are still developing. When we evaluate your child’s condition, plan their treatment and provide their care, we carefully consider their growth. We think about how growth may affect your child’s hands and feet over time. We also consider how joined digits — and treatment for them — may affect the rest of their development and health.
- We have the largest group of pediatric radiologists in the Northwest. If your child needs imaging that uses radiation, we use the lowest amount possible (PDF) to make the best image. We have a low-dose radiation X-ray machine, called the EOS. It makes safer full-body images.
Support for you and your family
- We know it can be stressful to have a child with a hand or foot difference and to find the treatment they need. Everyone at Seattle Children’s works to make your experience here as easy as we can on your whole family.
- Your child’s team does more than plan and provide care for your child. We also make sure you and your child understand your child’s condition and treatment options.
- Seattle Children’s supports your family with a range of resources. Our Child Life specialists, Family Resource Center and Guest Services are here to help.
Research to improve care
- Seattle Children’s takes part in the CoULD Registry for congenital upper limb differences. A registry is a place where researchers keep information about people who have a certain condition so they can learn more about it. CoULD connects researchers from children’s hospitals around the country to study treatments and improve life for kids born with arms and hands that aren’t typical.
- Learn more about current orthopedics research at Seattle Children’s.