Osteonecrosis, which is also called avascular necrosis (AVN) or aseptic necrosis, is the death of bone cells due to decreased blood flow. It can lead to pain and collapse of areas of bone. This collapse of bone, in turn, can lead to degenerative arthritis (also called osteoarthritis) of nearby joints, most often the hips and knees. Less often affected spots are the shoulders, hands and feet. Rarely, osteonecrosis can occur in the jaw. This can result in ulcers (sores) of gum tissue, exposed jaw bone and pain.
Doctors suspect osteonecrosis when a person with risk factors for it feels bone pain that is “localized” (limited to a small area). Patients with hip pain due to osteonecrosis often feel pain in the groin. Pain due to hip or knee osteonecrosis is most often worse with weight-bearing or walking.
The next step in diagnosis is to get an X-ray of the painful area. Because these X-rays may look normal in the early stages of disease, your doctor may schedule other imaging studies. These include bone scans or magnetic resonance images (often referred to as MRIs). MRI is excellent at helping detect very early osteonecrosis.