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What is tarsal coalition?

The bones of the foot found at the top of the arch, the heel, and the ankle are called the tarsal bones. A tarsal coalition is an abnormal connection between two or more of these bones. These coalitions can form across joints in your child’s foot or can occur between bones that don't normally have a joint between them.

About 25 percent of children with tarsal coalition have a rigid flat foot. The chief symptom of tarsal coalition is pain starting in late childhood or early adolescence.

  • Your child may experience rigidity and stiffness in around their ankle, and a decreased range of motion.
  • Treatment can be non-surgical or surgical, depending on its severity.
  • A severe case of tarsal coalition can interfere with the function of the foot and may interfere with a child’s activities. The condition is not life- or limb-threatening.

What are the tarsal bones?

The tarsal bones in the middle and back of the foot — the calcaneus, talus, navicular, and cuboid — together form joints that are extremely important to proper foot function.

When there’s abnormal growth of bone cartilage or fibrous tissue across these joints (tarsal coalition), a child’s range of motion either decreases or ceases entirely, causing pain and rigidity in the area.

The most common coalitions occur either:

  • across a joint between the talus and calcaneus bones (talocalcaneal coalition, also referred to as a TC bar)
  • between the calcaneus and navicular bones (calcaneonavicular coalition, also referred to as a CN bar)

Calcaneonavicular coalitions are more common than talocalcaneal coalitions. Together, these two types account for about 90 percent of all coalitions. There are other more rare types, as well. More than 50 percent of the time, tarsal coalition occurs in both feet. Sometimes both types of coalition are present in the same foot.

What causes a tarsal coalition?

Tarsal coalition can be a genetic error in the dividing of embryonic cells that form the tarsal bones during fetal development can sometimes be triggered by:

  • trauma to the area
  • infection
  • self-fusion of a joint caused by advanced arthritis (rare in children)

What are the symptoms of a tarsal coalition? When do they occur?

Even though most children with tarsal coalitions are born with them, painful symptoms typically set in sometime between the ages of 8 and 16. During late childhood and early adolescence children’s bones change from mostly cartilage to mostly bone (a process known as ossifying). During this period, the hardening (calcifying) tarsal coalition grows more rigid and painful. Sometimes symptoms don't flare up until early adulthood.

While each child may experience symptoms differently, the most common symptoms of a tarsal coalition include:

  • pain, typically on the outside and top of the foot (though some children have no pain)
  • flat feet or a flat foot (though not all children with flat feet have a tarsal coalition)
  • rigidity and stiffness in the affected foot
  • muscle spasms

How common is tarsal coalition?

Experts estimate that about 3 to 5 percent of people have a tarsal coalition. About 50 percent of these individuals have it in both feet.

How serious is tarsal coalition?

The answer to this question depends on the severity of the condition and your child’s level of activity. If sports are central to your child’s life, tarsal coalition could be viewed as a serious problem. If your child has only occasional aches, such as when running in gym class, and sports are not very important to them, the condition probably will not have a profound impact on their life.

A severe case of tarsal coalition can pose functional problems, make walking difficult, and may alter a child’s activity level. While treatment is recommended to improve function and relieve pain, the condition is not life-threatening or limb-threatening.

What if tarsal coalition goes untreated?

Over time, a child, teen, or young adult may experience enough pain that they can’t do the activities they enjoy. Later in life, they may have a very stiff foot (indicating a large coalition). The foot may be so stiff and painful that surgical repair is no longer an option. In such cases, a joint fusion would be the remaining option to alleviate pain.

Who’s at risk for developing tarsal coalition?

Tarsal coalition is a genetically determined condition. If one of a child’s parents has the condition, there is a chance that the child will also have it. If it occurs sporadically (by chance), it means that a genetic mutation took place during a child’s fetal development.

There is no genetic test available yet for tarsal coalition. Many people living with tarsal coalitions have few or no symptoms. Treatment of tarsal coalitions is only for symptomatic ones, therefore, evaluation for tarsal coalition occurs only for those people presenting with symptoms.

How we care for tarsal coalition

As part of the national and international referral Orthopedic Center at Boston Children's Hospital, our Lower Extremity Program offers comprehensive assessment, diagnosis, and treatment of lower limb conditions for children of all ages. Our specialists start with a conservative, non-surgical approach. If a case requires surgery, our surgical team has extensive experience correcting tarsal coalition, as well as other issues of the foot. We provide expert diagnosis, treatment, and care for every severity level of tarsal coalition to ensure our patients can live full, pain-free lives.

Tarsal coalition glossary

Terms to know
  • arthritis: joint inflammation and damage, resulting in pain, swelling, stiffness, and limited movement. Arthritis can occur when a joint’s cushioning cartilage wears away
  • bilateral: both of two sides
  • bone bridge: another term for the coalition that forms between the tarsal bones
  • calcify: harden into bone by the deposit of calcium salts into cartilage; ossify
  • CT scan (computerized tomography scan): the gold standard for the diagnostic imaging of tarsal coalitions; uses a combination of x-rays and computer technology to produce cross-sectional horizontal and vertical images (called "slices") of the body
  • diagnosis, diagnostics: identifying disease or injury through examination, testing, and observation
  • gait: manner of walking
  • Hale Family Center for Families at Boston Children’s Hospital: dedicated to helping families find the information, services, and resources they need to understand their child’s medical condition and take part in their care
  • lower extremities: parts of the body from the hip to the foot — includes hip, thigh, ankle, leg, and foot
  • MRI (magnetic resonance imaging): a diagnostic imaging tool that produces detailed images of organs and structures within the body
  • onset (of signs or symptoms): the first appearance of signs or symptoms
  • orthopedic surgeon, orthopedist: a doctor who specializes in surgical and non-surgical treatment of the skeletal system, spine, and associated muscles, joints, and ligaments
  • orthopedics: the medical specialty concerned with diagnosing, treating, rehabilitating, and preventing disorders and injuries to the spine, skeletal system, and associated muscles, joints, and ligaments
  • ossify: a natural progression as a child grows in which cartilage turns into bone or bony tissue
  • prognosis: outlook for the future
  • resection: a surgical procedure in which an organ or body structure is removed
  • sporadic: by chance
  • tarsal coalition: an inherited condition in which there’s an abnormal connection between two or more of the tarsal bones. These coalitions can form across joints of the foot or can occur between bones that don't normally have a joint between them.
  • x-rays: a diagnostic test that uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film; “standing” x-rays are x-rays taken while the child is standing up, as in diagnosing tarsal coalition

See our extensive Glossary of Orthopedic Terms.

Tarsal Coalition | Diagnosis & Treatments

How is tarsal coalition diagnosed?

The first step to treating your child’s tarsal coalition is to form a timely, complete, and accurate diagnosis. To diagnose your child’s condition, their doctor will conduct a physical exam. During the exam, the doctor will take your child’s complete prenatal, birth, and family medical history. They will also order standing x-rays as the initial imaging tool.

To confirm the diagnosis and give valuable information about the type of coalition, its location, and how the joints have been affected, either of the following diagnostic tests may be performed:

  • Computerized tomography scan (CT or CAT scan): Considered the gold standard for diagnosing tarsal coalitions, a CT scan is a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional horizontal and vertical images (called "slices") of the body. A CT scan shows detailed images of any part of the body — including bones, muscles, fat, and organs.
  • Magnetic resonance imaging (MRI): An MRI is a diagnostic procedure that uses a combination of large magnets, radio frequencies, and a computer to produce detailed images of organs and structures within the body. This test is done to rule out any associated abnormalities of the spinal cord and nerves.

Images will probably be taken of both of your child’s feet, even if only one foot is painful. This is because sometimes the child can have the condition in both feet (bilateral), yet only one foot is painful.

How is tarsal coalition treated?

About 75 percent of children with tarsal coalition never need treatment. And of the 25 percent who do, up to one half don't need surgery.

Your child's physician will determine whether your child needs treatment and what that will be determined by based on:

  • your child's age, overall health, and medical history
  • the extent of the condition
  • your child's tolerance for specific medications, procedures, or therapies
  • expectations for the course of the condition

Non-surgical treatments

The primary goal of conservative, non-surgical treatment is to reduce pain and muscle spasms by further reducing range of motion (immobilization) in the affected joint or joints. Treatments can include:

  • casts or walking boots
  • orthotics — special, custom-made shoe inserts that support affected joints
  • injection of an anesthetic and a steroid, such as cortisone, for temporary pain relief
  • anti-inflammatory medications
  • stretching and physical therapy

Surgical treatments

If your child's pain persists or recurs despite conservative measures, your child's doctor will probably recommend surgery.

  • The type of surgery depends on the type and location of the coalition, whether arthritis is involved, and, if it is, how extensive the arthritis is.
  • If there are no arthritic changes, the union between the bones is usually removed (resected), with fat or muscle placed where the tarsal coalition was so that normal range of motion can occur.
  • In more severe cases, surgery is aimed at limiting the range of motion in the joint that causes pain. In this instance, the surgery involves fusing affected joints to reduce pain.

After surgery, as part of the recovery process, a splint or cast, along with crutches, are used to immobilize the foot and keep the foot from bearing weight. Exercises to restore muscle tone and range of motion are encouraged as early as one to two weeks after surgery. Walking and full strengthening begins about one month after surgery.

Care after surgery

After surgery, your child will probably stay in the hospital overnight, and be given pain medication. They will wear a cast when they go home and will need to limit their weight-bearing activities for about a month. They may use crutches or a walker for a few weeks. At this point, therapy is aimed mostly at regaining range of motion and preventing the bone bridge (coalition) from reforming.

After about a month your child will transition into a walking boot and begin strengthening exercises. Physical therapy will help restore their muscle strength. They'll probably be able to resume full activities, including sports, after three to six months. However, a full recovery can take up to a year.

What is the long-term outlook for my child with tarsal coalition?

Only a small percentage of children with tarsal coalition need treatment for it. And one-third to one-half of those who need treatment can be treated without surgery.

Of those who are treated either non-surgically or surgically, about 75 percent become free from pain and do not have a recurrence of the condition.

There is a risk that the repaired joints or surrounding joints may develop arthritis later in your child’s life.

Tarsal Coalition | Research & Clinical Trials

Research & Innovation

For more than a century, orthopedic surgeons and investigators at Boston Children’s Hospital have played a vital role in advancing the field of musculoskeletal research. We’ve developed breakthrough treatments and major advances for lower limb and hip problems, as well as for scoliosis, polio, tuberculosis and traumas to the hand and upper extremities.

Our pioneering research helps answer the most pressing questions in pediatric orthopedics today—to provide children with the most innovative care available.

In Boston Children’s Hospital's Orthopedic Center, we take great pride in our basic science and clinical research leaders, who are recognized throughout the world for their achievements. Our orthopedic research team includes:

  • full-time basic scientists
  • 28 clinical investigators
  • a team of research coordinators and statisticians

Orthopedic basic science laboratories

Working in Boston Children’s labs are some of the leading musculoskeletal researchers in the nation. Our labs include:

Children speak about what it's like to be a medical research subject

View a video of a day in the life of Boston Children's Clinical and Translational Study Unit, through the eyes of children who are “giving back” to science. 

Boston Children's Hospital Hip Program's unique insight and expertise

Boston Children’s Hospital's  Child and Adult Hip Preservation Program enjoys a special degree of effectiveness—not just because of our long tradition of excellence in pediatric hip care, but also because we follow our patients through adulthood. This gives us a unique perspective, insight and expertise—we can track how the hip works in each age group, how the problems evolve, and how the hip’s function changes over time in adult patients who’ve had treatment in childhood.

Tarsal Coalition | Programs & Services