Musculoskeletal CT Appearances

Heterotopic Ossification CT Findings

• Amorphous calcification
  • Starts as a soft tissue mass
  • Poorly defined without clear trabecular formation
• Immature ossification
  • Trabecular formation with poorly defined margins
• Mature ossification
  • Cancellous bone interior with a cortical outline

Other Information About Heterotopic Ossification

Etiology:

• Trauma
• Bone replacement surgery (particularly hip replacement)
• In rare instances may be genetic

Epidemiology:

• Twice more common in males
• Males typically present in 3rd and 4th decades of life while females typically present after age 65

Presentation:

• Swelling
• Joint pain
• Joint warm to touch
• Decreased range of motion

Prognosis:

• Pain can be managed with medication and physical therapy
• More serious cases may require surgery, after which prognosis is generally good