Do you feel both images are similar? Well if you look carefully, the arrow marked femoral head also knows as ball of hip joint is smooth, spherical and well contoured in image 1, whereas in image 2, the outline of femoral head or the ball is irregular, not so well contoured with loss of its sphericity. This is what is knows as Avascular Necrosis of Femoral head. Nowadays its a very common scenario in my OPD where even young fellas visit me with hip pain and when i get the xray done, this is what I see. AVN (Avascular Necrosis ) term has become quite well known. It has different grades and each grade has different line of management. The biggest challenge is early diagnosis of this condition. Stay tuned for more updates on this.