Myositis ossificans in hemophilia.

A review of the radiographs of 60 hemophilia patients showed nine (15%) with ectopic new bone formation. Three of these patients had multiple sites of involvement. The high frequency discovered in this series contrasts with the paucity of descriptions to be found in the literature. This process of myositis ossificans affects the lower half of the body and probably represents dysplastic metaplasia developing at the site of an intramuscular hematoma when remote from bone, as well as ossification of hemorrhagic lesions related to the periosteum. In conventional radiographs anatomic localization of bone foci is difficult, but use of computed tomography permits precise identification of the affected muscle. There is negligible disability associated with this condition.