Pathophysiology of Osteonecrosis

Osteonecrosis is a common disorder in which a segment of bone loses its blood supply and undergoes significant and at times very disabling and deforming changes. The causes of osteonecrosis are many but are principally associated with bone injury, thrombosis or embolism, external pressure on a vascular wall, or increased venous pressure. There are two types of osteonecrotic entities: medullary osteonecrosis affecting only the medullary cavity and trabecular bone and corticocancellous osteonecrosis affecting an adjacent joint. The purpose of this presentation is to describe the pathophysiology of these two entities, their causation and their effect on the patient.