What is Tarsal coalition?

Tarsal coalition is a condition that occurs when one or more joints in the foot or tarsus fails to form properly during development. This is often an inherited disorder. Although any joint in the foot may be affected, the most common sites are the calcaneo-navicular joint and the talo-calcaneal joint.

Instead of forming the usual synovial joint, the joint is replaced by fibrous tissue, cartilage or bone. This decreases the flexibility of the foot in motion, and causes undue stress to the foot.

What are the symptoms?

The typical presentation is a child or adolescent between the ages of 8 and 16 years of age, who complains of pain in his foot. It can be bilateral in more than 50% of cases. The patient often has flatfeet, which is quite rigid and painful. Although the tarsal coalition is present at birth, symptoms do not appear till later because that is the time the coalition starts to transform from fibrous tissue or cartilage to bone.

What does your doctor do about it?

Your doctor will order X-rays to confirm the diagnosis. The views taken include AP, lateral, oblique and axial views to visualize the calcaneo-navicular joint and the talo-calcaneal joint. Often, CT scan or MRI may be needed if the X-rays appearance is uncertain.

Treatment is conservative initially. It should be remembered that 75% of people with tarsal coalition do not have symptoms, and the purpose of conservative treatment is to convert these 25% of people with symptoms to aymptomatic ones. Arch supports or walking casts for 6 weeks often relieve the symptoms.

In patients where the symptoms are not relieved by conservative means, and impair function, surgery to excise the coalition is often successful. It is not possible to create a synovial joint, but by placing a muscle or fat in the space after excision, recurrence is prevented, and symptoms are usually relieved.