What is a Tarsal Coalition?

There is a condition called a tarsal coalition in which two of the bones in the tarsal region (rearfoot) of the foot are abnormally fused together. This tarsal region of the foot includes seven bones known as the tarsal bones, which are located between the leg bones (tibia and fibula) and the bones of the forefoot (metatarsals). A tarsal coalition most commonly affects the bones known as the talus, calcaneus and sometimes the navicular bone. The fusion between these bones can be a fibrous soft tissue where there is a bridge of fibrous tissue that connect the two bones. The fusion could also be osseous where there is a bony bridge fusing the two bones. This fusion between the bones restricts the normal movement and flexibility of the joints that are affected resulting in a range of different symptoms depending on the bones that are involved. A tarsal coalition is often not detected early in children as the foot as the foot is still very flexible, but around the adolescent years the symptoms start to appear. The actual causes of these tarsal coalitions are not fully understood, however it is believed to be a congenital condition, meaning it has been present from birth. In some cases, in adults, the tarsal coalition may also result from trauma or arthritis.

Typically, the common symptoms associated with tarsal coalition are somewhat vague and can include pain in the area that is often initially hard to locate at one joint between the involved bones. That pain will typically worsen with increased activity and get better with rest. There will be a stiffness and limited range of motion in the joint or joints that are affected. The coalition may cause fatigue or muscle cramps in the affected leg or foot. There may be an abnormal gait or walking pattern such as a limp. There may also be an alignment problem such as a flatfoot or high-arched foot deformity may develop. The final diagnosis of tarsal coalition is usually made through a combination of clinical signs and history of the symptoms and then imaging studies such as X-rays or a CT scan. The imaging will show the abnormal bony fusion or fibrous connection between the tarsal bones.

The treatment for tarsal coalition will depend on the severity of symptoms and the impact that they have on daily activities. Non-surgical approaches are usually tried first and will include the avoiding of activities that worsen symptoms or cause pain. Foot orthotic devices can provide support and reduce excessive movement in the affected joints. Stretching and strengthening exercises can help improve joint flexibility of the other joints around the affected areas. If the pain is particularly problematic, then nonsteroidal anti-inflammatory drugs (NSAIDs) may be used to reduce pain and inflammation. If these measures do not provide sufficient relief and it is severe then surgical intervention may be considered. The purpose of the surgery is to separate the fused bones by removing the bridge between them to try and restore normal joint motion.

Craig Payne is a University lecturer, runner, cynic, researcher, skeptic, forum admin, woo basher, clinician, rabble-rouser, blogger and a dad.