ACE2 and COVID-19: In direct mechanisms, SARS-CoV-2 directly targets ACE2 expressed cells in the musculoskeletal system.109 Studies on ACE2 expression of the musculoskeletal system indicated skeletal muscle, synovium, and cortical bone as a potential site of direct SARS-CoV-2 infection.109 The indirect mechanism of COVID-19–induced musculoskeletal manifestations is caused by overactivated immune responses and COVID-19–induced cytokine storm.