Avascular necrosis (also known as osteonecrosis, ischemic bone necrosis, and aseptic necrosis) is a condition that occurs when a bone's blood supply is disrupted, resulting in cell death and eventual bone collapse. The lack of blood supply causes the bone to become weakened and eventually die. In the early stages, the bone may become painful and swollen, and it may eventually collapse or break due to the weakened state.
The most common cause of avascular necrosis is a traumatic injury, such as a fracture or dislocation, that disrupts the blood supply to the bone. In some cases, the injury may not be severe enough to cause an immediate problem, but the disruption of the blood supply can cause damage over time. Other causes of avascular necrosis include disease, such as lupus, or chemotherapy; medications, such as corticosteroids; and alcohol abuse.
In some cases, the cause of avascular necrosis is unknown. This is known as idiopathic avascular necrosis. It is believed that the condition may be caused by a combination of genetic and environmental factors.
Regardless of the cause, avascular necrosis can be a serious and disabling condition. It can lead to pain, swelling, and limited range of motion in the affected area. In some cases, the condition can even lead to joint replacement surgery. Treatment is typically focused on reducing pain and preserving the joint. This may include medications, physical therapy, and in some cases, surgery.