Posterior facet talocalcaneal non-osseous coalition: an uncommon but easily missed cause of hindfoot pain

Magnetic resonance imaging (MRI) showed the medial posterior facet of the subtalar joint to be abnormally oblique on sagittal plane, and the involved joint space was narrowed and irregular with adjacent marrow oedema (Fig 2). In particular, CT is useful in determining the presence of any small bony bridging and is important for surgical planning; MRI is able to provide information about the degree of marrow oedema that may correlate with level of pain. Potential complications of posterior facet coalition include peroneus muscle spasms, sinus tarsi syndrome, tarsal tunnel compression giving rise to a distended posterior tibial vein, calcaneal stress fracture, and premature osteoarthritis.1 4 Early recognition of non-osseous posterior facet talocalcaneal coalition is important, particularly in young patients, as surgical treatment can reduce complications later in life.