Bone necrosis. The death or necrosis of bone due to the obstruction of its blood supply.
Osteonecrosis is a bone disorder that results from the loss of blood supply to the bones. The lack of blood supply causes the bone to collapse and generally leads to the collapse of articulating joints such as the hip joint. Osteonecrosis is most likely to occur at the ends of long bones such as the femur or in the knee. Osteonecrosis may affect only a single bone, or it may affect multiple bones. Osteonecrosis usually occurs in early adulthood through midlife (20s-40s) but can occur in younger and older individuals. This disorder affects both men and women equally. In the United States alone, osteonecrosis is estimated to affect 10,000 to 20,000 new people each year. There is no indication that osteonecrosis occurs in one ethnic group more frequently than in any other.
The death of a segment of bone usually caused by insufficient blood flow to a region of the skeleton. This is a relatively common disorder and an estimated 10% of total joint replacements are for osteonecrosis. From 5% to 25% of patients receiving prolonged therapy with corticosteroids will develop this condition. Treatment is symptomatic, but in some cases of osteonecrosis of the knee or hip joint prosthetic replacement is required.