While hiking in October, 2015, I suffered a medial meniscus tear in my left knee.  Over time it worsened, and I had arthroscopic surgery in January, 2016.  I had a quick recovery and am again running a couple times a week.  I still get an occasional stabbing pain in the knee while running, but then I slow down and change my stride a little bit and after a minute or two the pain is gone and I resume my normal running.  This happens in BOTH knees, and was occurring for many years before the tear, so it's not necessarily related to the tear.   Since I know I have less of my meniscus in my left knee, I was wondering if prolotherapy would be able to increase the cartilage there, or whether the fact that it was cut away surgically means that the amount lost is too great to be significantly changed by prolotherapy.  Do you have any experience with the effect of prolotherapy on joints where the cartilage had been surgically trimmed  back to remove the torn portions?