Osteochondroma-Related Distal Tibiofibular Synostosis with an Isolated Subtalar Joint Degeneration and Flexor Hallucis Longus Tendon Entrapment

Osteochondroma is the most common benign tumor or tumorlike lesion of bone. The radiographic appearance is often diagnostic, that is, a lesion composed of cortical and medullary bone with a cartilage cap. These lesions may be solitary or multiple, with the latter associated with the syndrome HME. Complications are commonly associated with its exophytic nature and include cosmetic and osseous deformity, fracture, vascular compromise, neurologic sequelae, overlying bursa formation, and malignant transformation. These complications are more common in patients with multiple lesions (HME) rather than solitary osteochondromas [1]. Although related complications are mostly about the exophytic nature of tumor itself, we present a case of distal tibiofibular synostose via an osteochondroma in a HME patient that was complicated with subtalar joint degeneration and flexor hallucis longus tendon entrapment, being the first case in literature.