Avascular necrosis of the femoral head can be categorized into two types.

The first is traumatic avascular necrosis, which results from the interruption of blood supply to the femoral head.

The second is non-traumatic avascular necrosis, which has various causes. It is commonly associated with excessive alcohol consumption, chronic liver disease, long-term use of steroids, and related conditions such as kidney transplantation, all of which can lead to avascular necrosis of the femoral head.

Statistics show that among patients with non-traumatic avascular necrosis, approximately 14% to 74% have a history of excessive alcohol consumption, indicating that excessive drinking is a significant contributing factor.

The exact pathological mechanism remains unclear. Some suggest that it may be due to the release of pancreatic enzymes causing fat necrosis, followed by calcification. The bone sclerosis observed on X-rays represents the calcified areas resulting from fat necrosis.

Another explanation is that excessive alcohol consumption can lead to transient hyperlipidemia and alter blood coagulability, potentially causing vascular occlusion, hemorrhage, or fat embolism, which in turn leads to ischemic necrosis.