Medically Reviewed by Dr Wang Lushun What's Avascular Necrosis (AVN)? Avascular necrosis, also called osteonecrosis, happens if the blood provide to bone cells is disrupted, resulting in the death of bone tissue. It generally targets the hip joint, notably the femoral head–the upper “ball” portion of the femur (thigh bone) https://www.theorthopaedicandpainpractice.com/what-is-avascular-necrosis-of-the-hip/?_gl=1*xbbxlb*_up*MQ..&gclid=Cj0KCQjwkt6aBhDKARIsAAyeLJ2krYJSOuy5mZksrNqH-VDjQwW1ScD49yD8BUWysDG6u6bJPCSbXVUaAuCPEALw_wcB