Episode 9: Heterotopic ossification (HO)

featured guest Bridget Ripa

Notes by Alexis Lancaster

What is it?

  • The formation of bone inside soft tissue structures, where it’s not supposed to be
  • It is extra-articular, so it occurs outside of the joint capsule


What is involved? How does it happen?

  • Exact pathophysiology is unknown
  • Usually comes from a period of immobilization or traumatic injury to that bone or to the affected area of the body



  • Swelling, redness, warm to the touch
  • Similar to a DVT presentation
  • Presents similarly to an infection within that area, such as thrombophlebitis, osteomyelitis, cellulitis, sepsis, septic arthritis
  • Can present as a fracture, trauma, bruise, hematoma


Special tests

  • XRay (gold standard)
  • Bone scan


Treatment examples

  • As the PT you can’t change the bone formation once it occurs
  • Maintain ROM of the joint/area
  • Maintain strength
  • Prophylaxis is important: before HO occurs, you want to make sure you are paying attention to maintaining ROM with positioning, splinting/bracing early on to avoid HO development


On the NPTE

  • Might be integrated into a question
  • “During an initial evaluation of a patient s/p MVA with a complete lesion at C7, the PT notes redness, swelling, and warmth at the posterior knee joint. Which of the following conditions would most likely be present?
    • Dependent on answers if HO is an answer, you can go with that
    • Could be DVT, as well
    • Consider answers that are available on the test!