Heterotopic Ossification after Severe COVID-19 Pneumonia: Radiological Findings in the Current Literature

Abstract

Melissa Fang, Gabrielle Wasilewski, Alexander Kui, Bennett Dwan, Rishabh Choudhari, Anup Jacob Alexander and Emad Allam*

Heterotopic ossification is the aberrant formation of extraskeletal bone in muscle and soft tissues. Its many causes include joint arthroplasty, traumatic or neurologic injury, burns and rare genetic disorders. In non-genetic forms, an inciting event causes inflammatory cell-mediated interactions to convert progenitor cells to osteogenic precursor cells which can form new bone over the span of weeks to months. There is an intriguing association between severe COVID-19 pneumonia and heterotopic ossification. In September 2020, a case series on two Dutch patients documented the development of ectopic bone in the hips, shoulders and elbows after severe COVID-19 pneumonia requiring prolonged mechanical ventilation in the intensive care unit. In the following two months, six more patients presented similarly. More cases have been identified since the original reports. This paper seeks to explore the work published in this interim and provide updates on radiological findings.