A tarsal coalition is a condition characterised by the abnormal fusion of two or more tarsal bones in the back of the foot. This unnatural connection can lead to an inflexible flatfoot, causing intense pain. In more severe cases, it significantly restricts mobility and reduces patients’ quality of life.
Estimates suggest that approximately one percent of the population has a tarsal coalition, with about half of those cases affecting both feet. Diagnosing this condition can be challenging, as many patients show no symptoms.
Although some tarsal coalitions can go undetected due to the lack of noticeable symptoms or malformations, many are diagnosed when the following symptoms are present:
Tarsal coalition frequently begins during prenatal development due to genetic alterations affecting the cells responsible for tarsal bone formation. While the condition originates before birth, its symptoms often appear later in childhood or adolescence.
When babies are born, the percentage of soft, malleable cartilage within their feet is higher. Over time, the cartilage gradually undergoes ossification and hardening as the bones mature. In certain instances, this process leads to the formation of a coalition – an additional connection that could potentially increase the stiffness of the hindfoot as it undergoes mineralisation and solidifies into bone. This typically takes place between the ages of eight and sixteen, depending on which bones are involved, and it leads to uncomfortable symptoms.
Non-surgical treatment options for tarsal coalition include:
When conservative measures are inadequate for relieving pain and improving mobility, surgical intervention may be recommended. Two common surgical treatments for tarsal coalition are detailed below.
Surgery called resection is commonly used to treat tarsal coalition. During this procedure, the abnormal connection is replaced with muscle or fatty tissue from another part of the body. This helps keep the foot moving normally and often reduces symptoms, especially in people without arthritis.
When tarsal coalition causes more severe problems, like arthritis and significant structural changes, joint fusion may be needed. This surgery aims to reduce joint movement and place the bones in a better position. To achieve this, pins, screws, or plates can be used to secure the bones in place.