Tarsal coalition is a congenital anomaly in which an abnormal connection is formed between bones in the foot. This connection may consist of a fibrous, cartilaginous, or osseous bridge that disrupts the normal motion between tarsal bones and may lead to a painful rigid flat foot. Over time, the loss of foot motion may also result in arthritis.
The 2 most common sites for tarsal coalition include the calcaneonavicular joint and the middle facet of the talocalcaneal joint. The estimated prevalence of tarsal coalition is 1% in the United States; however, the prevalence may be underestimated, as >75% of those with tarsal coalition have no symptoms. Those affected often become symptomatic between the ages of 9 and 13 years, when ossification of the coalition is most likely to occur. A history of recurrent ankle sprain and difficultly walking are common complaints.1,2
Radiographic evaluation is the first step in diagnosing tarsal coalition. Anteroposterior, lateral, 45-degree oblique, and axial views of the foot are recommended. Computed tomography scan best details the size, location, and orientation of the coalition and should be performed in anyone suspected of having tarsal coalition. Magnetic resonance imaging is also helpful in identifying fibrous or cartilaginous coalitions as well as other potential causes of ankle pain.
Conservative treatment is recommended initially, including nonsteroidal anti-inflammatory drugs, arch supports, and immobilization. Surgical treatment is considered when pain is persistent and conservative measures have failed.1,2
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor-in-chief of the Journal of Orthopedics for Physician Assistants (JOPA).
- Vincent KA. Tarsal coalition and painful flatfoot. J Am Assoc Orthop Surg. 1998;6(5):274-281.
- Carli A, Leblanc E, Amitai A, Hamdy RC. The evaluation and treatment of pediatric tarsal coalitions: a critical analysis review. JBJS Reviews. 2014;2(8):e2