Tarsal coalition is an abnormal connection between two bones at the back of your foot toward the ankle. This connection causes irregular forces on the bone, leading to pain and other problems. What is a tarsal coalition, and what can you do about it if you have it?

Tarsal bones 

tarsal bones

The tarsal bones comprise seven bones in the middle and the back of the ankle. They provide movement up and down and in (inversion) and out (eversion), working harmoniously to provide smooth function. Three of these bones – navicular, calcaneus and cuboid – are ususally involved in tarsal coalition.

What is tarsal coalition? 

A tarsal coalition occurs when two bones grow into each other, connected by bone, cartilage, or fibrous tissue. This connection means that these bones move together and not separately. The common sites of a tarsal coalition are between the talus and calcaneus and the navicular and calcaneus.

We think approximately 5% of the population has tarsal coalition. About 50% of cases affect both feet.

How does tarsal coalition present? 

Generally, tarsal coalitions become problematic in children from 9-16 years. However, in some cases, symptoms do not occur until adulthood.

More commonly, teenagers report increasing aches and pains in the ankle during and after activity. Sometimes, pain may occur after a minor or innocuous injury such as an ankle sprain. In some cases, a foot coalition might lead to repeated ankle sprains despite rehab. Finally, children might present with a sudden flat foot due to excessive muscle spasms in more severe cases.

Diagnosis 

tarsal coalition on X-ray

Your doctor will examine your ankles and feet to see if you have signs consistent with tarsal colation. Generally, we find stiffness in the ankle and subtalar joint as the foot coalition prevents free movement of the bones independently. Sometimes, we see a flat foot that doesn’t correct with rising on toes.

If we suspect a tarsal coalition, we move on to imaging. Firstly, a plain X-ray of the ankle can see the coalition. Then, we use an MRI scan for more sensitive images of the ankle and mid-foot. Often, MRI will pick up the abnormal connection with swelling on either side. Finally, a CT scan will confirm whether the connection is made up of bone or cartilage.

Tarsal coalition treatment 

We only recommend treatment if the foot coalitions are causing symptoms. Generally, we recommend a step-up approach starting with simple remedies and moving to more interventional treatment.

Conservative treatment 

Simple treatment includes rest from high-impact sports for a short period. Sometimes a boot might be needed if the pain is severe.

Generally, we recommend you see a podiatrist to consider shoe insoles. We think that inserts help support and stabilise your ankle and foot, leading to reduced pain. Also, physiotherapy to strengthen the small muscle of the foot and the large calf muscle will help.

We recommend a cortisone injeciton at the coalition site to relieve pain in some cases.

Surgical treatment

We should only consider surgery if non-surgical treatments have failed. The type of surgery we offer depends on several factors, including the site of the foot coalition, the severity of symptoms, and whether you have arthritis.

Resection of the coalition is the most common procedure. We remove the coalition and replace it with muscle or fat from another part of the body. This procedure retains the bones’ normal movement, meaning that foot function is preserved.

In some cases, fusion is needed for larger, more severe coalitions or where arthritis has developed. Often screws and plates are used to keep the bones fused.

More on ultrasound-guided cortisone injection for tarsal coalition 

We reserve cortisone injections for painful or severe cases unresponsive to simple treatment. We recommend performing injections with ultrasound to improve accuracy and effectiveness. Ususally, we target the coalition between the two bones.

Other frequently asked questions on tarsal coalition: 

If left untreated, what happens to the tarsal coalition? 

In some cases, pain is at a level that stops people from playing sport. If pain continues, then arthritis can develop. Thus, it is essential to get the pain under control.

Is tarsal coalition genetic? 

Yes. But not all cases are solely due to genetics. Sometimes, trauma or arthritis can lead to a coalition.

Final word from Sportdoctorlondon about tarsal coalition 

Always suspect a tarsal coalition in a teenager or adult who has persistent pain in the ankle after a minor injury. Early diagnosis means quicker treatment and a faster return to sport.

Other related conditions:

Dr. Masci is a specialist sport doctor in London. 

He specialises in muscle, tendon and joint injuries.

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