Avascular Necrosis as a Sequela of COVID-19: A Case Series.

Avascular necrosis (AVN) is a degenerative bone condition characterized by cellular death and bone collapse from compromised subchondral blood circulation. AVN begins with vascular interruption, hypertension, intravascular occlusion, or extravascular compression which reduces bone circulation. Although corticosteroids are frequently used to treat acute COVID-19 infections, patients are prone to its side effects, particularly AVN. Furthermore, COVID-19 produces coagulopathies, specifically hypercoagulability, that may contribute to venous thrombosis, which may serve as the impetus of AVN. While the literature discussing COVID-19, AVN, and corticosteroid use is not conclusive, patients being treated with corticosteroids for COVID-19 are at an increased risk for AVN possibly due to the combination of COVID-19 infection and corticosteroid use, or the use of high-dose steroids alone. The purpose of this case series is to elucidate AVN as a long-term sequalae of COVID-19, describe our management of COVID-19 and steroid-induced AVN, and discuss the current literature regarding AVN and COVID-19. Three patients hospitalized for COVID-19 infections were treated with corticosteroids and subsequently developed AVN. All patients, but one, had multiple sites of infarction and were treated with core decompression in the hip where there was no collapse of the subchondral bone. One of these patients had multiple infarcts in bilateral femoral heads, femoral shafts, and knees. This patient had a history of end-stage renal disease, and, therefore, total knee replacement was postponed until medical clearance. Core decompression was performed on the femoral head that showed no collapse to delay osteoarthritis of the hip. Multiple articles in the current literature support the idea that the combination of COVID-19 and corticosteroid use increases the risk of AVN and reduces the onset of COVID-19-related respiratory symptoms. The patient cases discussed in this case series suggest a possible association between COVID-19, corticosteroid use, and AVN.