Avascular Necrosis of the Knee

For tissue to remain healthy and function normally, it requires a healthy blood (vascular) supply. Patients can develop a rare condition in their subchondral bone (bone beneath and supporting the joint surface) called avascular (“without blood”) necrosis (“death/dying”), or AVN, where the bone loses blood supply, dies, and then fractures and eventually collapses without proper treatment. AVN usually affects bone just under the joint surface and can lead to collapse of the joint surface and painful arthritis.

There are two types of AVN: traumatic and atraumatic. Traumatic AVN may occur following an injury such as a dislocation, while atraumatic can happen with certain diseases, blood disorders, or taking medication such as corticosteroids. Occasionally, it can develop for no discernible reason.