Myositis ossificans of the upper arm.

Myositis ossificans is a benign condition resulting from severe muscular contusion manifested by heterotrophic bone formation. The process is common in the anterior thigh but the literature dealing with myositis ossificans in the upper arm is limited. Ten cases of the condition in the upper arm were seen in our practice. All 10 were the result of football injuries and exhibited one or more of the triad of local pain, a hard palpable mass in the muscle, and a flexion contracture of the elbow. Seven of the cases (70%) were asymptomatic or signficantly improved in less than 3 months with conservative nonoperative management. Three patients (30%) underwent surgery because the painful mass persisted. In two (66%) of the surgically managed cases, there was clinical and radiographic evidence of recurrence postoperatively in spite of delaying excision until radiographic parameters of maturation were present.