[Traumatic myositis ossificans. Posttraumatic non-neoplastic heterotopic ossification]

Myositis ossificans traumatica (MOT) is a nonneoplastic, heterotopic ossification of soft tissues i.e. skeletal muscle, tendons, aponeuroses and fascia. It is often encountered in young male athletes participating in contact sports as a result of a single or repeated contusion. MOT tends to be solitary, localized and well circumscribed with a self-limited growth potential that may culminate in regression. The pathogenesis of MOT is still enigmatic. Recent animal experiments have led to a theory that mesenchymal connective tissue cells, undergo metaplasia induced by trauma and probably osteogenic proteins, to fibroblasts and osteoblasts. These cells deposit and structure osteoid centripetally in the lesion. As the lesion matures, cancellous bone develops into mature, lamellar bone in the periphery of the lesion. In its earlier stages MOT is easily cytologically and radiologically confused with osteogenic sarcoma. The management of MOT is largely conservative and the principles are of considerable value to physicians and physiotherapists engaged in the treatment of sports injuries. This article reviews the various forms of myositis ossificans as well as the pathology, diagnosis and treatment options.