Serial Ultrasonography for Early Detection and Follow-up of Heterotopic Ossification in Stroke

Heterotopic ossification (HO) is a common complication in patients with neurologic deficits. Once developed, limited range of motion may occur and interfere with rehabilitation programs. Early diagnosis is crucial but difficult because radiographs may be negative, and similar clinical symptoms could appear in deep venous thrombosis, cellulitis, and osteomyelitis. A three-phase bone scan can detect the disease early, but it has high radiation and low specificity. Magnetic resonance imaging (MRI) may also assist in diagnosis, but is costly and has some contraindications. Ultrasonography has been used in HO detection and is safe, economical, easily accessible, and involves no radiation exposure. However, a few studies have described its use in HO, especially in serial follow-ups. We report a case with HO clinical symptoms, but the MRI results created a necrotizing fasciitis suspicion. Serial ultrasonography images implied the formation of HO rather than necrotizing fasciitis. Ultrasonography images serve as a good initial screening tool for HO and are useful for following up such dynamic disease processes.