Posttraumatic Heterotopic Ossification Clinical Presentation

Updated: Feb 04, 2021
  • Author: Auri Bruno-Petrina, MD, PhD; Chief Editor: Stephen Kishner, MD, MHA  more...
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The earliest sign of heterotopic ossification (HO) often is decreased joint ROM. Other findings include swelling, erythema, heat, pain with ROM testing, and contracture formation, but the condition may be occult. Fever also may be present. Patients with HO can experience pain, increased spasticity, vascular and nerve compression, and lymphedema.



In heterotopic ossification (HO), ectopic bone usually forms around major joints (eg, elbows, shoulders, hips, knees) following brain injury, as well as over long-bone fractures. The proximal interphalangeal joints of the hand, wrist, and spine also may be affected. Local pain and a palpable mass may be noted in the periarticular region, usually presenting 1-3 months after the injury, but the onset of HO also has been reported at 1-7 months following severe brain injury. [5]

HO can mimic thrombophlebitis, with pain, swelling, erythema, and induration of the affected area. If HO affects a joint, a decrease in ROM often is observed. Major, long-term disability from untreated HO can include limited ROM or even joint ankylosis.

In patients with a history of fractures, spasticity, and low-level responsiveness, the detection of restricted motion should suggest HO. Excessive bone formation may result in significant disability by severely limiting the ROM of a joint.

Complete elbow ankylosis without severe injury of the CNS has been described.



Patients with brain injuries are at greater risk for developing heterotopic ossification (HO) if they have significant spasticity or increased muscle tone in the involved extremity, unconsciousness lasting longer than 2 weeks, long-bone or associated fractures, and decreased ROM. Therefore, the risk of development of HO in a patient with brain injury increases as the severity of injury, length of immobilization, and duration of coma increase.

In patients with fibrodysplasia ossificans progressiva (FOP) (often misdiagnosed as cancer), any soft-tissue trauma (eg, biopsies, surgical procedures, intramuscular injections, mandibular blocks for dental procedures) and viral illnesses are likely to induce episodes of rapidly progressive HO, with a resultant permanent loss of motion in the affected area.