Posttraumatic Heterotopic Ossification Differential Diagnoses

Updated: Feb 04, 2021
  • Author: Auri Bruno-Petrina, MD, PhD; Chief Editor: Stephen Kishner, MD, MHA  more...
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Diagnostic Considerations

The differential diagnosis for heterotopic ossification (HO) in patients with soft-tissue swelling or loss of ROM includes thrombophlebitis, cellulites, septic arthritis, hematoma, fracture, or local trauma. The presence of fever due to HO may mimic deep venous thrombosis in presentation or osteomyelitis from hematogenous or contiguous spread.

FOP, a rare, genetic, autosomal dominant disease characterized by episodes of permanent HO of soft tissues, occurs worldwide without race, ethnic, or geographic predilection. No effective treatment is available, and soft-tissue trauma (eg, biopsies, surgical procedures, intramuscular injections, mandibular blocks for dental procedures), as well as viral illnesses, are likely to induce episodes of rapidly progressive HO, with a resultant permanent loss of motion in the affected area. Accurate diagnoses can be made based on the clinical findings of tumorlike swellings on the head, neck, back, or shoulders and characteristic short great toes with hallux valguslike malformations and missing interphalangeal joints.

For the nonfunctional shoulder, 70 º of abduction and 45 º of external rotation are usually sufficient to allow access to the axilla for washing and sufficient ROM for dressing. HO, typically inferomedial, does not interfere with ROM; restriction of shoulder motion is more likely attributable to other soft-tissue tightness. If present at the shoulder, HO is likely to be present at other joints, such as the elbow, hips, or knees; in these locations, HO usually causes a considerable number of clinical problems.