Avascular necrosis as a part of post-COVID syndrome. Case reports

Coronavirus disease 2019 (COVID-19) can manifest with a wide range of extrapulmonary symptoms and have longterm consequences (so-called post-covid syndrome (PCS) or “long COVID-19”). Manifestations of PCS show a wide clinical spectrum and include cardiac, pulmonary, neurological, gastrointestinal, dermatological, mental symptoms, vascular thrombosis and avascular necrosis (AVN) of the bones.We present our own observations of the development of bone’s AVN in 3 patients who underwent COVID-19 with bilateral lung disease, in whom after 4–6 months the first signs of AVN were noted and characterized by a progressive multifocal lesion, which was accompanied by an increase of C-reactive protein concentration.The pathogenetic mechanisms of AVN development in the framework of PCS are discussed. The importance of conservative and surgical methods in the treatment of the disease are considered. Since the development of AVN of various localizations with a long latent period is possible after COVID-19, long-term monitoring of patients is required. Further study of the problem of PCS in general and AVN in particular is required.