Bone, Joint and Muscle Conditions

Tarsal Coalition

What is tarsal coalition?

Tarsal coalition is a type of flatfoot. It occurs when 2 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.

About 1% to 2% of people have tarsal coalition. 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.

  • Tarsal coalition 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. 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.

    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.

Tarsal Coalition at Seattle Children’s

Tarsal coalition is treated by the experts in our Foot and Ankle Deformities Program.

Dr. Vincent S. Mosca, chief of foot and ankle medicine at Seattle 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 recently has worked on surgical procedures for the most complex and severe cases of tarsal coalition. His procedure is becoming the preferred method to treat the problem.

  • Many of our pediatric orthopedic surgeons have expanded fellowship training in areas such as foot and ankle conditions, sports medicine, tumors, upper extremity surgery, limb deformity, neuromuscular diseases, skeletal dysplasia and spine problems. To restore or improve your child’s health, function and quality of life, we often use nonsurgical methods (like medicines, physical therapy and braces), recommending surgery only when we believe it will give your child the best results.

    We have the largest group of board-certified pediatric radiologists in the Northwest. Our radiologists have special expertise using ultrasound to look for bone and joint changes so we can work with your child to help prevent future problems. If your child needs imaging that uses radiation, we use the lowest amount possible to produce the best image. We also have a 3D low-dose radiation X-ray machine, called the EOS, for safer full-body 3D images.

Symptoms of Tarsal Coalition

Children with tarsal coalition may have foot pain. Usually, you cannot see an arch in their foot or feet when they stand up.

Diagnosing Tarsal Coalition

First, the doctor examines your child’s foot. The doctor will look at their feet as they stand up, or may ask your child to stand on tiptoe or dangle their foot in the air as they sit on an exam table.

When children have a form of rigid flatfoot, such as a tarsal coalition, the arch is usually not visible when they stand on tiptoe or let their foot hang down. In other types of flatfoot, the arch appears when children stand on tiptoe or let their feet dangle.

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

The doctor may order 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 (computed tomography) scan.

Nonsurgical Treatment for Tarsal Coalition

We treat all children with tarsal coalition conservatively. Our goal is to end their pain.

For children with mild cases, this means cutting back on the activities that cause pain and taking anti-inflammatory medicines.

If your child has more severe pain, they may wear a cast or a rigid boot for about 6 weeks to hold their foot still. This is called immobilization treatment. 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 recommend 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. Then the doctor puts fat or a small, nearby muscle in the place of the tarsal coalition.

    After this operation, your child will wear a cast for 3 weeks. They are not allowed to walk on the foot for at least 6 weeks. We teach your child exercises to help them regain movement in the joints of their feet.

  • For children with the most severe and widespread tarsal coalitions and those with the flattest feet, joint-preserving surgery may help. We developed this procedure at Seattle Children’s.

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

Contact Us

If you have questions about tarsal coalition treatment, call our Orthopedics and Sports Medicine Department at 206-987-2109. If you would like an appointment, ask your child’s primary care provider for a referral.

Providers, see how to refer a patient.