Avascular Necrosis?

Good morning all. I try to stay in an up-beat mood, but it's hard to do today. I was diagnosed with avascular necrosis of the left hip bone and joint about four years ago. In AVN, the blood supply to the area just diminishes and dies out leaving the bone to die. It caused me quite a bit of pain in my left leg and the orthopedic surgeon said that it was not quite bad enough for a hip replacement and that I would know when it was time as the bone would begin to chip. I went about on crutches for several months. Then miraculously, the pain went away for about two and a half years. I even was able to walk a couple of miles a day on the school track. However, in the last three weeks the pain has returned to my lower leg, between the knee and ankle. Yesterday and today it is really giving me a fit and I am living on pain killers. My appointment with the doc is not until next Wednesday and I know that a hip replacement will be in the works. Has anyone had any experience with this problem? My doctor has offered no suggestions except wait till it get's so bad that a replacement is necessary. I'm curious as to why, if the problem is in the hip, all the pain is in the lower leg, and what caused the problem in the fist place.
Well, I don't mean to bore anyone with this, I just thought maybe someone else had some suggestions. I feel better just talking about it.