not-yet-known not-yet-known not-yet-known unknown SARS-COV-2 sever illness and Guillain-Barré syndrome: a dual etiology for heterotopic ossification of the hip. BELKEBIR MRANI Mamoun, (1) SCHUMANN Léa, (1) COLETTE Alain Orthopedics and traumatology unit, CHU UCL Namur Sainte Elisabeth, Namur, Belgium