Myositis ossificans of the thigh following manipulation of the knee. A case report.

Myositis ossificans of the thigh produced severe limitation of knee motion in a 22-year-old man after passive manipulation of a knee on three separate occasions. Motion improved after excision of the bony mass and postoperative radiation to prevent recurrence. Caution is advised in passive manipulation of the knee, because repeated attempts can result in forced extension of the quadriceps muscle, periosteal damage, partial muscle tears, and interstitial hemorrhage.