<unk>  usually affects people between 30 and 50 years of age; about 10,000 to 20,000 people develop<unk>  of the head of the femur in the US each year.
Avascular necrosis
Legg–Calvé–Perthes disease
Acral necrosis
Osteopetrosis
Dysbaric osteonecrosis
Rheumatoid arthritis
Osteoradionecrosis
Sickle cell disease