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Tarsal Coalition

What is tarsal coalition?

Tarsal coalition is a type of flatfoot. It occurs when two or more of the tarsal bones, found in the middle and back of the foot, join together. These bones are usually separate.

Tarsal coalition belongs to the category of flatfoot called rigid flatfoot. The feet of children with tarsal coalition look the same as the feet of children with other forms of flatfoot.

Their feet angle outward from the leg and they do not have an arch in the middle. But feet with a tarsal coalition are stiff, not flexible like some other forms of flatfoot.

Rigid flatfeet with tarsal coalition.
Rigid flatfeet with tarsal coalition.

Unlike with other forms of flatfoot, babies are not born with a tarsal coalition. Instead, their feet flatten out as they get older, usually between the ages of 8 and 16.

Common sites for tarsal coalition

Each of the tarsal bones has a name. The most common sites for a tarsal coalition are between the calcaneus and navicular bones and between the talus and calcaneus bones.

About half of cases involve the first set of bones and about half involve the second set. In some cases, both sets of the bones are joined together in the same foot.

Rigid flatfeet with tarsal coalition.
Rigid flatfeet with tarsal coalition with heels lifted.

How do you evaluate tarsal coalition?

First, we examine your child’s foot. We look at her feet as she stands up, and we may ask her to stand on tiptoe or dangle her foot in the air as she sits on an exam table.

When a child has a form of rigid flatfoot, such as a tarsal coalition, we usually cannot see an arch in her foot when she stands on tiptoe or lets her foot hang down.

In other types of flatfoot, the arch appears when children stand on tiptoe or let their feet dangle.

We also check the joints in your child’s feet and ankles. If your child’s ankle does not move much, it could mean that her Achilles tendon is shortened or tight. That may make it more likely she will have pain and disability.

We may take X-rays to see if your child’s calcaneus and navicular bones are joined together. To check the talus and calcaneus bones, we use a CT scan.

Who gets tarsal coalition?

About 1% to 2% of people have tarsal coalition. It is an inherited (genetic) condition; parents with tarsal coalition can pass it on to their children. It is not associated with any other medical problems.

The good news is that only about a quarter of people who have tarsal coalition have problems with it or need treatment. Of those who need treatment, a third to half are helped without surgery.

What is your experience with tarsal coalition?

Dr. Vincent S. Mosca, chief of foot and ankle medicine at Children’s, is a leader in clinical research on foot problems in children and teenagers.

Flatfoot, including tarsal coalition, has been a focus of his work. He has recently worked on surgical procedures for the most complex and severe cases of tarsal coalition, and his procedure is becoming the preferred method to treat the problem.

How do you treat tarsal coalition?

First, we treat all children with tarsal coalition conservatively and our goal is to end the pain. For children with mild cases, this means restricting the activities that cause pain and taking anti-inflammatory medicines.

If your child has more severe pain, she may wear a cast or a rigid boot for about six weeks to hold her foot still (called immobilization).

Some children’s feet will remain free of pain after we remove the cast or boot.

Surgery for tarsal coalition

For pain that comes back or continues after we have tried the immobilization treatment, we offer a full range of surgical options. We choose surgical treatments based on the type, severity and complexity of your child’s tarsal coalition.

In early and mild cases, we may perform an operation to remove the tarsal coalition and put fat or a nearby small muscle in its place.

After this operation, your child will wear a cast for three weeks. She is not allowed to walk on the foot for at least six weeks. We will teach her exercises to help her regain movement in the joints of her feet.

Failed resection.
Failed resection.

Joint preserving surgery

For the most severe and extensive tarsal coalitions, and for children with the flattest foot deformities, we offer a procedure developed at Children’s Hospital called joint preserving surgery.

Our research has shown that the operation for flexible flatfoot (calcaneal lengthening osteotomy) also works to relieve pain and correct the deformity of severe tarsal coalitions.