It has been suggested this is merely an organizing hematoma. Other authors think the periosteum has been pushed into the muscle or the osteoblasts escaped the periosteum. Metaplasia of connective tissue cells is also a possibility. Treatment for myositis ossificans is generally conservative. Early surgery is contraindicated.
Excision is an option after decreased activity is evident on bone scan.
Treatment and Prognosis, W.B. Saunders, Co., 1991. Cushner, FD and RM Morwessel, Myositis Ossificans Traumatica, Orthopaedic Review, p. 1319-1326, November, 1992.