We often see tarsal coalition when a child or teenager develops a stiff, painful flatfoot, has repeated ankle sprains, or suddenly has difficulty with sports. A coalition is an abnormal connection between two bones in the foot. It may be made of bone, cartilage, or fibrous tissue. Some people have a coalition without symptoms, while others develop pain and stiffness as the bones mature. The important question is not simply whether a coalition appears on an X-ray or CT scan. We want to know whether it is causing the symptoms, restricting motion, and changing how the rest of the foot works.
Anatomy
The bones in the back and middle of the foot normally move in relation to one another. A coalition creates an abnormal bridge between them and restricts that movement.
The two locations we see most often are a calcaneonavicular coalition, between the heel bone and navicular, and a talocalcaneal coalition, between the talus and heel bone.
When motion becomes restricted, the foot may compensate by becoming flatter and the heel may tilt outward. Some patients develop muscle spasm around the outside of the ankle, and the foot can become particularly stiff when walking on uneven ground.
Symptoms
Patients may describe pain in the foot or ankle, stiffness, tired legs, or difficulty with walking, running, or sports. Repeated ankle sprains can also be a clue.
We pay close attention to whether the foot is truly flexible. A patient may look like they simply have flat feet, but the lack of normal hindfoot motion can point toward a coalition. Some people have no symptoms at all and discover the coalition incidentally on imaging.
What happens at the first visit
We start by watching how you stand and walk rather than looking only at the scan.
We examine the height of the arch, the position of the heel, and the amount of motion through the ankle and hindfoot. We also look at what happens when you stand on your toes. With a flexible flatfoot, the arch may reappear; with a coalition, restricted motion may prevent the foot from correcting normally.
We then put the examination together with the symptoms. A coalition on an imaging study does not automatically explain someone’s pain.
Imaging
X-rays are usually the starting point. A calcaneonavicular coalition can produce an “anteater nose” appearance on an oblique X-ray, while a talocalcaneal coalition may produce a “C-sign” on a lateral X-ray.
X-rays do not show every coalition clearly, particularly when the connection is fibrous or cartilaginous. CT can define the size, location, and bony anatomy of a coalition. MRI can help identify a fibrous or cartilaginous coalition and show changes in the surrounding soft tissues.
We use the imaging to answer a specific clinical question. We do not treat the scan by itself.
Similar Diagnoses
A stiff or painful flatfoot can have several causes. Depending on the examination, we may also consider flexible flatfoot, posterior tibial tendon problems, sinus tarsi syndrome, subtalar arthritis, or other causes of a spastic flatfoot.
The examination matters because these conditions can look similar from the outside but require different treatment.
When we consider surgery
We consider surgery when the coalition is clearly contributing to persistent symptoms and appropriate nonsurgical treatment has not provided enough improvement. The decision also depends on the location and size of the coalition, the condition of the surrounding joints, and whether the foot has developed a significant deformity.
When the surrounding joints are healthy and the foot is otherwise appropriate for preservation, the coalition may be resected, meaning the abnormal bridge is removed. Tissue can then be placed between the bones to reduce the chance of the connection reforming.
If there is significant malalignment or flatfoot deformity, correcting the alignment may also be necessary. If the coalition is extensive or there is advanced arthritis, fusion of the affected joint may be considered instead.
Surgery
Coalition resection is more than simply removing an abnormal piece of bone. The abnormal connection is removed, and tissue may be placed between the bones to help prevent them from reconnecting. The specific technique depends on the location of the coalition.
The other important part of surgical planning is evaluating the overall alignment of the foot. When a significant deformity is present, addressing the alignment may be necessary in addition to treating the coalition itself.
Recovery
Recovery depends on the procedure performed and the condition of the foot before surgery. The source material describes an initial period of casting or boot immobilization with restricted or no weight bearing, followed by gradual physical therapy to restore motion and strength.
The early goal is healing. After that, the focus becomes restoring motion, strength, balance, and confidence in the foot. Recovery can take longer when additional realignment or fusion is required.
An asymptomatic coalition may simply be observed. A symptomatic coalition that continues to restrict motion can contribute to chronic pain, progressive flatfoot mechanics, arthritis, and reduced mobility.
That does not mean every coalition will inevitably worsen. It means that persistent symptoms and mechanical changes deserve evaluation rather than being dismissed as “just flat feet.”
Outcomes
A good outcome is not simply a better-looking X-ray. The goal is a foot that is less painful, functions better, and allows the patient to return to the activities that matter to them.
For some patients, that may mean returning to sports. For others, it may simply mean walking, standing, or participating in daily activities without persistent pain and stiffness.
The treatment plan should match the patient’s symptoms, the amount of motion available, the foot’s alignment, and the condition of the surrounding joints.
When you should see a doctor
Arrange an evaluation for persistent or worsening foot pain, increasing stiffness, repeated ankle sprains, or difficulty with normal activities.
After an injury, severe pain, inability to bear weight, an obvious deformity, or signs of infection such as significant redness, swelling, or fever require prompt medical attention.
The content on this page has been authored, edited, or approved by the doctors below, and was last reviewed for accuracy on September 15, 2026.
