# Heterotopic Ossification After COVID-19: A Case Report and Review of Literature

## TL;DR

A 31-year-old woman developed non-traumatic bone growth in her hips and knees after a long hospitalization for severe COVID-19.

## Contribution

This case highlights heterotopic ossification as a rare but possible complication of prolonged immobilization in severe COVID-19 patients.

## Key findings

- The patient developed HO in the vastus medialis and hips without trauma.
- Alkaline phosphatase levels spiked but returned to near-normal after treatment with indomethacin and etidronate.
- The patient regained some mobility but had persistent joint limitations.

## Abstract

We report a 31-year-old woman hospitalized for approximately two months for coronavirus disease 2019 (COVID-19) pneumonia. Under sedation, she received physiotherapy to prevent joint contractures. When weaning from the mechanical ventilator began, she complained of pain and limited range of motion in her bilateral hip and knee joints. Radiography and computed tomography revealed non-traumatic heterotopic ossification (HO) in the bilateral vastus medialis and hips. Range-of-motion exercises were discontinued, and treatment with indomethacin and etidronate disodium was started. Alkaline phosphatase, an index of disease activity, peaked 15-fold higher than the normal range but decreased to near-normal levels four months after treatment. She could walk with a T-cane after rehabilitation, although her range of motion remained limited. If a COVID-19 patient has joint pain and is immobilized for a long time, HO should be considered accordingly.