Can short courses of systemic corticosteroids truly cause osteonecrosis?

One of the most feared complications of long-term corticosteroid therapy is osteonecrosis (avascular necrosis, aseptic necrosis). There is, no doubt, a causal role for systemic corticosteroids inducing osteonecrosis with such chronic therapy. The controversy involves whether short-term (<1 month) courses of systemic corticosteroids can truly induce osteonecrosis. This article presents both the biologic basis and statistical support for why such short-term courses of systemic corticosteroids rarely, if ever, truly induce osteonecrosis. Data from two very large populations (renal transplantation and systemic lupus erythematosus) with overall increased risk for osteonecrosis are carefully examined in view of the aforementioned controversy.