Myositis Ossificans: Definition and Treatment
Myositis ossificans is a benign condition of heterotopic bone formation within muscle tissue, typically following trauma, that requires conservative management with rest, ice, compression, and elevation, with surgery reserved only for mature lesions causing significant functional impairment. 1, 2
What is Myositis Ossificans?
Myositis ossificans (also called myosteosis or hematoma ossificans) is characterized by calcification of a hematoma that develops after severe contusion, muscle strain, or repeated microtrauma to soft tissues. 1, 3 This is a benign, self-limiting process—not a malignancy—that displays a characteristic zonal pattern of mineralization with peripherally more mature ossification. 4, 2
Key Clinical Features:
- Most commonly affects the extremities (arms, legs, shoulders, hands), rarely the chest or masticatory muscles 3, 5
- Typically occurs in teenage athletes and young adults in their third decade of life 3
- Rare in children under 10 years of age 3
- 60-75% of cases have a clear post-traumatic onset 3, 6
Diagnostic Approach:
Imaging is essential to differentiate myositis ossificans from malignant sarcoma and to determine lesion maturity before any intervention. 6
- Radiographs first: Should be the initial imaging study to detect the characteristic zonal pattern of calcification and rule out bone tumors 4
- CT imaging: Superior for detecting the zonal pattern of mineralization essential to early diagnosis, particularly when radiographs remain nonspecific or in anatomically complex areas 4
- Ultrasound: May serve as a primary investigation tool for superficial lesions 3
- MRI: Provides better diagnostic assessment for lesion characterization and maturity determination 3, 6
The peripherally mature ossification pattern is pathognomonic and distinguishes myositis ossificans from malignant soft tissue sarcomas, which typically show central mineralization. 4
Treatment Algorithm
Initial Conservative Management (First-Line for ALL Cases):
Apply the RICE protocol immediately upon diagnosis or clinical suspicion: 1
- Rest the affected area completely
- Ice application to minimize inflammation
- Compression to limit hematoma extension
- Elevation when possible
Rehabilitation Phase:
- Initiate gentle, painless range-of-motion exercises only after the acute phase to restore mobility 1
- Use protective padding over the affected area to prevent additional trauma 1
- Avoid aggressive physical therapy or manipulation, which can worsen ossification 6
When to Consider Surgical Excision:
Surgery should be delayed until the lesion is fully mature (typically 6-12 months after onset), as premature intervention inevitably results in recurrence. 6 Consider excision only when: 3, 6
- Significant functional impairment or severe limitation of joint motion persists
- Considerable lesion size causes mechanical problems
- Severe, intractable pain despite conservative measures
- Diagnostic uncertainty remains despite imaging (requires histological confirmation)
Critical pitfall: Operating on immature myositis ossificans leads to recurrence—imaging must confirm lesion maturity before any surgical intervention. 6
Long-Term Management:
Because myositis ossificans is self-limiting with spontaneous resolution in most cases, conservative treatment with radiological follow-up is the preferred approach when imaging shows typical features. 3 Serial imaging monitors lesion maturation and guides timing of any necessary intervention.
Special Populations:
In paraplegic or immobilized patients, myositis ossificans can complicate pressure sore management and wound healing, requiring careful consideration of the ossification in treatment planning. 6