This causes progressive secondary arthritis and may lead to the collapse from the bone. This can be brought on by abnormal microcirculation and causes cell death (necrosis). Standing up and sitting down down: Increasing from a seated posture or lowering into a chair is often complicated for individuals with hip pain, https://www.theorthopaedicandpainpractice.com/what-is-avascular-necrosis-of-the-hip/?_gl=1*xbbxlb*_up*MQ..&gclid=Cj0KCQjwkt6aBhDKARIsAAyeLJ2krYJSOuy5mZksrNqH-VDjQwW1ScD49yD8BUWysDG6u6bJPCSbXVUaAuCPEALw_wcB