Osteonecrosis

Osteonecrosis literally means bone death. For bone, death comes when it loses its supply of nutrition or blood supply. Osteonecrosis is a relatively common cause of knee pain in older men and women occurring when a segment of bone loses its blood supply and begins to die.

Three areas of the knee are most commonly affected. The medial femoral condyle (inside part of the upper leg) is most often affected. Osteonecrosis may also occur on the lateral femoral condyle (outside part of the upper leg) and the tibial plateau (top flat portion of the lower leg).