Postacute sequelae of SARS-CoV-2 infection. Osteonecrosis must not be overlooked.

Recovery from COVID-19 is not always uneventful, especially in critically ill hospitalized patients. Persistent symptoms including fatigue/ weakness, shortness of breath, anxiety, and depression have been described at one-year follow-up. Furthermore, symptoms from the musculoskeletal system like joint pain or stiffness are underreported in studies with long-term follow-up of up to one year. Infection with SARS-CoV-2 itself has been associated with endothelial damage, and together with high-dose corticosteroid treatment, it is predisposed to the dissemination of microthrombi and the development of femoral head osteonecrosis (FHOn), as it has been shown during the previous (2003-2004) coronavirus outbreaks. A resurgence of FHOn cases is anticipated but this is not reflected in the existing studies with long-term follow-up. Prompt diagnosis is critical for early treatment and possibly for the hip joint preservation. Patients with COVID-19 treated with corticosteroids should be screened for avascular necrosis early after discharge from the hospital. Every healthcare worker involved in the management of these patients should maintain a high level of suspicion and should be alert when patients report symptoms such as vague aches at the buttocks, hip area, adductors, and/or above the knee. Studies are needed to identify risk factors for FHOn including disease severity, type of steroid, cumulative dose, and duration of treatment.