The amount of disability that results from<unk>  depends on what part of the bone is affected, how large an area is involved, and how effectively the bone rebuilds itself. The process of bone rebuilding takes place after an injury as well as during normal growth. Normally, bone continuously breaks down and rebuilds—old bone is resorbed and replaced with new bone. The process keeps the skeleton strong and helps it to maintain a balance of minerals. In the course of<unk> , however, the healing process is usually ineffective and the bone tissues break down faster than the body can repair them. If left untreated, the disease progresses, the bone collapses, and the joint surface breaks down, leading to pain and arthritis.
Avascular necrosis
Legg–Calvé–Perthes disease
Acral necrosis
Osteopetrosis
Dysbaric osteonecrosis
Rheumatoid arthritis
Osteoradionecrosis
Sickle cell disease