Steroid-associated osteonecrosis: Epidemiology, pathophysiology, animal model, prevention, and potential treatments (an overview)

Xie, Xin-Hui; Wang, Xin-Luan; Yang, Hui-Lin; Zhao, De-Wei; Qin, Ling

Osteonecrosis (ON) is a disabling clinical disease characterised by death of the osteocytes and the bone marrow, followed by resorption of the necrotic tissues and formation of new but weaker osseous tissue which leads to a progressive destruction of bone architecture, subchondral fracture, and collapse of joints, mostly occurring at the femoral head, and finally loss of joint function [1e3] . Alexander Munro first reported this medical condition in 1738 and Cruveilhier firstly attributed this disorder to an aberration of circulation in the femoral head in the mid 1800s [4] . Similar terms to ON include avascular necrosis (AVN), ischemic necrosis, subchondral AVN, aseptic necrosis of bone, or osteochondritis dissecans. AVN or ischemic necrosis is used to describe their vascular aetiology, while aseptic necrosis is used to indicate that the infection does not play an important role in ON occurrence and its development. ON occurs mostly in large weight-bearing joints, such as the hip (Fig. 1 ) that may subsequently develop to joint collapse and end up with joint replacement surgery.