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Heterotopic Ossification


Pronounced: Het-toro-toe-pik Oss-if-a-kay-shun


Heterotopic ossification (HO) is the growth of bone in places where it’s not supposed to be. It can happen anywhere in the body. The hip, knees, shoulders, and elbows are the most common places. Growths can be small or large.


The cause of HO is unknown. There may be a genetic link. HO can also happen because of trauma.

Risk Factors

Your chances of HO are higher if you have:

  • Traumatic brain injury or stroke
  • Recent spinal cord injury—mainly within the past 1-4 months
  • Hip surgery or other joint surgery
  • Burns
  • Long period of immobility
  • Joint infection
  • Fractures
  • Some tendon injuries


Symptoms depend on how serious HO is. It also depends on where there is bone growth. HO may cause:

  • Decreased range of motion
  • Swelling or redness to joint(s)
  • Pain
  • Fever


The doctor will ask about your symptoms and health history. You may also have:

  • A physical exam
  • Blood and urine tests
  • Tests on fluids from your skin or cysts
  • Imaging tests:

You may be referred to a specialist.

X-ray of Pelvic Repair
repiared pelvis x-ray

HO may not show up on x-ray until later stages.

Copyright © Nucleus Medical Media, Inc.


The level of care needed depends on how serious HO is. Care may involve:

Physical Therapy

Therapy is an important part of your care plan. Range of motion exercises will help to move around better. It can also keep the HO from getting worse. This may include stretching and strength training.


Your doctor may advise:

  • Non-steroidal antiinflammatory drugs (NSAIDs) to reduce swelling and pain
  • Bisphosphonates to prevent the bone loss

Radiation Therapy

Radiation therapy may help prevent abnormal bone growth, mainly after hip surgery.


Surgery may be used to remove the abnormal bone. This will help improve range of motion. Radiation therapy and medicines are mainly used after surgery to prevent recurrence.


There’s no way to prevent HO because the cause isn’t known. If you’re at high risk for HO, talk to your doctor.


Ortho Info—American Academy of Orthopaedic Surgeons

United Spinal Association


Canadian Orthopaedic Association

When it Hurts to Move—Canadian Orthopaedic Foundation


Back DL, Smith JD, Dalziel RE, Young DA, Shimmin A. Incidence of heterotopic ossification after hip resurfacing. ANZ J Surg. 2007;77(8):642-647.

Heterotopic ossification. Craig Hospital website. Available at: Updated January 2015. Accessed June 21, 2018.

Pape HC, Marsh S, Morley JR,  Krettek C, Giannoudis PV. Current concepts in the development of heterotopic ossification. J Bone Joint Surg Br. 2004;86(6):783-787.

Spinal cord injury—InfoSheet #12. Spinal Cord Injury Information Network website. Available at: Accessed June 21, 2018.

Zychowicz ME. Pathophysiology of heterotopic ossification. Orthop Nurs. 2013;32(3):173-177.

Last reviewed May 2018 by EBSCO Medical Review Board Marcie L. Sidman, MD  Last Updated: 6/21/2018