Tarsal coalition is a congenital condition in which there is an abnormal connection (coalition) between the bones of the hindfoot (the tarsal bones). It occurs when the bones fail to separate from each other during early development.
Since the bones in early childhood are primarily made of cartilage, coalitions are soft early on and are often unnoticed. As the cartilage gradually turns into bone, coalitions become stiffer and are more prone to injury with activity. It is therefore typical that children will not have a noticeable problem until late childhood or adolescence. Tarsal coalitions can cause activity-related foot pain, stiffness, or recurrent ankle sprains. Some children never have symptoms and do not require treatment.
The two most common types of tarsal coalition are located between the:
- Calcaneus and navicular bones
- Calcaneus and talus bones, although any bones in the hindfoot can have a coalition
About fifty percent of children with tarsal coalitions have them in both feet. It sometimes runs in families. Initial treatment is aimed at reducing symptoms. Simply decreasing sports activities for a couple weeks can sometimes help, although this isn’t always necessary if symptoms are mild. Over-the-counter anti-inflammatory medication (such as ibuprofen or naproxen) and icing can also reduce symptoms. If initial treatment is unsuccessful, customs shoe inserts or a trial of walking cast immobilization can sometimes help.
Surgical treatment is often indicated if conservative treatment fails and symptoms persist. The exact surgical procedure needed depends on the type and severity of the tarsal coalition. The expected outcomes and risks of complications from surgery are variable, and depend on the type of surgery needed.