For those of you considering ACI be sure to ask your surgeon how experienced he is at doing them. Ask where and how he learned the procedure. If they don't want to answer you, find another surgeon. Get a second opinion if it is suggested to you. It's not a miracle cure. I speak from experience. The surgeon who did it to me presented it to me as if he did it all the time. In fact I was his first patient. His training was some manuals dropped off and a video. The pharma rep, unknown to me was in the OR with him, he was the surgeons mentor. After six months of therapy and still having problems the surgeon reluctantly ordered an MRI which showed the bone patch had come off. Another surgery to remove it and many more after that. After investigating the surgeon admitted he had never done the procedure before....Several years of hell because of this. Not to mention a total knee replacement. And don't let the "only surgeons who have completed the training procedure" thing fool you. Call the company and ask them just exactly what the training is.