An emergency department client is diagnosed with a hip dislocation. The client's family is relieved that the client has not suffered a hip fracture, but the nurse explains that this is still considered to be a medical emergency. What is the rationale for the nurse's statement

A traumatic hip dislocation is a medical emergency and needs to be treated immediately, ideally within 6 hours. That is because the injury stops blood from reaching the top of the femur, depriving the bone of its vital oxygen supply. Unless the dislocated hip is replaced in its socket promptly and normal circulation is restored within the hip joint, the top part of the femur can be permanently damaged. This permanent damage is called avascular necrosis.