Complex tarsal coalition includes extensive talocalcaneal coalition, double or triple coalition, coalition with severe hindfoot deformities, or coalition with a ball-and-socket ankle deformity. Careful preoperative physical examination including diagnostic injection is important in treatment planning. Both radiographic examination and computed tomographic scan that involve not only the foot but also the ankle are necessary to analyze the location and size of the coalitions, determining the presence of arthritis in the involved or adjacent joints, and if there are any deformities including a ball-and-socket ankle, which is frequently associated with complex tarsal coalitions.
