Osteonecrosis is a condition where bone tissue dies due to an interruption of blood supply. It can affect any bone but most commonly affects the hip joint. Symptoms include joint pain and tenderness. Doctors diagnose through x-rays, MRI, CT scans, and bone scans. Treatment depends on the stage of disease and may include medications to improve blood flow, hyperbaric oxygen therapy, electrical stimulation, core decompression surgery, bone grafts, or in severe cases, joint replacement surgery.