How can aseptic necrosis of bone lead to secondary osteoarthritis?

Aseptic necrosis (also known as osteonecrosis) leads to secondary osteoarthritis primarily through the structural failure of bone tissue near a joint.12

When the blood supply to the cancellous bone of the epiphyses is interrupted, the bone tissue dies. During the subsequent repair process, the body attempts to remove the necrotic bone and replace it with new bone. If this rebuilding process is insufficient or if the bone is subjected to mechanical stress before it has fully healed, the structural integrity of the bone weakens.1

This weakened bone can collapse under the normal mechanical forces exerted across the joint. Once the underlying bone structure collapses, the overlying joint cartilage is damaged or loses its support, leading to the development of secondary osteoarthritis. Because of this risk, early clinical management of aseptic necrosis often focuses on preventing the affected joint from bearing weight to allow the bone to heal without collapsing.12