Osteonecrosis of bone. Current concepts as to etiology and pathogenesis.

Experimental and some clinical evidence suggest that one or more mechanisms, alone or in combination, induce bone necrosis. These include marrow cell hypertrophy, microembolic phenomena, and lipid-induced osteocyte necrosis. Such events may result in local inflammatory exudates and/or vascular impedence. Either may effect an increase in the hydrostatic pressures in bone with the potential to limit blood flow and magnify the initial insult. Further experimental investigations are necessary to gain knowledge of etiologic mechanisms and a rational means of prophylaxis or treatment.