Thanks, TF! At therapy, I usually have to limit or quit exercises because my RIGHT knee hurts. I hate to grind that one down even further. I feel pretty confident that my left is strong enough now to get me through surgery, so by June is certainly should be ready. It will be so wonderful to have a good set of wheels again, won't it. Bad news--my exercise bike is clunking and making very awful noises. This happened once before when a bearing went bad. It was about 3 weeks to get it fixed. I don't know if I can do without it for that long

.
scaredinCA The short answer to your question about why I waited so long: I was always told to try and hang on until I was 50. A brief rundown on how this all happened: I injured my right knee when I was just 13. At that time, they just took out the entire meniscus, so there has been nothing between my bones (better than nothing between my ears!) since then. I proceeded to be in all kinds of sports in high school and college, plus I really enjoyed running. Maybe not so smart, but when you are a teen, you don't think about the future. I got by, but eventually, the space between the bones narrowed and the cartilage covering the leg bones wore away--thus the grinding we all know so well.
In the mean time, I injured my left knee playing volleyball, had that one cleaned out with orthoscopic surgery a few times. I was having so much pain and not sleeping, so I had both my knees scoped in 2011. It was a chance for the OS to get a good look inside. Seems my ACL ligament in my left was stretched beyond being useful in addition to the bones grinding. He then said anytime I was ready for replacement, so was he. In just a year and a half since then, the left had become so crooked and unstable that we decided to do that one first even though the right one has been bone on bone forever. (I remember when I first injured my left. When the doc saw my Xray, he said, "are you sure it's your left knee that hurts. I would do a replacement on your right knee right now." That was in 1988). I guess that wasn't very brief, was it.
Have a good day to all. I have some therapy later, so I am resting. I will take my bike apart and hope it's just the squirrel inside getting off track.