Immunologic factors in the pathogenesis of osteonecrosis.

Osteonecrosis is a disease in which death of cellular elements of bone occurs as a result of diminished arterial blood supply. The pathogenetic mechanisms of osteonecrosis remain unresolved. Extravascular pressure and subsequent tamponade of the arterial vessels or an intravascular thrombosis have been suggested. Immunologic factors may also play an important role. In autoimmune disorders, small vessel vasculitis or other disease-associated features, as well as antiphospholipid antibodies, have been involved in the development of osteonecrosis.