Tarsal Coalition

A tarsal coalition occurs when there is a failure of the differentiation of some of the foetal mesenchyme into the distinct tarsal bones. This results in partial fusions or bridges of bone between some bone in the tarsus of the rearfoot. Initially there are usually no symptoms of a tarsal coalition as there is some movement between the bones as the joint between them are still cartilage. As there ossify and the child becomes more active, they tend to  become more rigid and the tarsal coalition becomes symptomatic. The classic signs are a limitation of movement of the joint and the fusion of bone is visible on x-ray. The most common tarsal coalitions are a talocalcaneal coalition and a calcaneonavicular coalition. Sometimes a peroneal spastic flat foot develops as the spasm in the muscles protects the joint from moving. Treatment is usually started with physical therapy for the symptoms and foot orthotic to restrict the movement of the joint. If that is not successful, then a surgical removal of the bridge of bone is often carried out.