Also called: Aseptic necrosis, Avascular necrosis, Ischemic necrosis

Osteonecrosis occurs when your bones lose their blood supply. The bones die and eventually collapse, leading to pain and arthritis. You can have osteonecrosis in one or several bones. It is most common in the upper leg. Other common sites are your upper arm and your knees, shoulders and ankles. The disease can affect men and women of any age, but it usually strikes in your thirties, forties or fifties. Early in the disease you might not have any symptoms. Later, you will probably have joint pain that becomes more severe as the disease gets worse. No one is sure what causes the disease. Risk factors include Long-term steroid treatment Alcohol abuse Joint injuries Having certain diseases, including arthritis and cancer Treatments include medicines, using crutches, limiting activities that put weight on the affected joints, electrical stimulation and surgery.