Myositis ossificans of the elbow is a severe and relatively common complication of elbow trauma, accounting for approximately 3% of elbow fractures and dislocations.

bubble_chart Pathogenesis

After severe injuries such as elbow fractures and dislocations, the periosteum is stripped or ruptured, a hematoma forms, or the local area is subjected to passive stretching or surgical stimulation, leading to hematoma formation. These factors can trigger an ossification process primarily driven by hematoma calcification. After the hematoma is absorbed, the ossification gradually progresses beneath the periosteum. Currently, the mechanism is not entirely clear but can be summarized into two theories: the periosteal osteogenesis theory and the fibrous tissue transformation osteogenesis theory.

The occurrence of myositis ossificans is associated with the following factors:

1. Repeated forceful passive movements.

2. Timing of treatment—early treatment can achieve good reduction, reduce hematoma formation, and facilitate soft tissue repair.

3. Age—children have a lower chance of developing myositis ossificans compared to young adults.

bubble_chart Diagnosis

There is a clear history of trauma; repeated passive flexion and extension of the joint after injury; persistent joint swelling and pain accompanied by localized temperature increase; gradual reduction in joint range of motion; no specific findings on X-ray in the early stage, with cloud-like ossification masses appearing around the joint after 3–4 weeks. In the advanced stage, the ossification area shrinks, density increases, and boundaries become clear. Generally, there is a tendency for enlargement within 3–6 weeks after injury, stabilizing after 6–8 weeks.

1. General Treatment: After the diagnosis of myositis ossificans is confirmed, the elbow joint should be properly protected. Whether active joint exercise should be performed depends on the specific condition. If there is local swelling, tenderness, increased temperature, or aggravated pain during movement, excessive activity should be avoided. If the above symptoms are not obvious, exercise should be performed within tolerable pain levels to maintain a certain degree of joint mobility and function.

2. Radiation Therapy: Some believe that radiation therapy can influence the inflammatory response process and prevent the occurrence of myositis ossificans. It is administered twice a week for four weeks (one course), with each session delivering 200R.

3. Surgical Treatment: Surgery should only be considered when myositis ossificans affects the flexion and extension function of the elbow joint and is in a quiescent state—i.e., when the heterotopic ossification is densely sclerotic with clear boundaries. The goal of resection is to ensure no residual muscle or bone tissue related to the ossified mass remains, to prevent recurrence. During resection, the ossified mass should be removed along with a thin layer of normal muscle, and hemostasis must be thorough. Postoperatively, the elbow should be immobilized with a gypsum cast for 1–3 weeks.