@krisluhman and @cobweb this all might be true if doctors had all the answers and they don’t. Just ask one whether they know it all and you’ll most likely receive similar answers. Our bodies are still a mystery in so many ways, healthcare science just keep finding new and amazing facts about our bodies. Try checking out the Institute of Human Anatomy on YouTube to learn more about our amazing bodies. Since knees take a long time to get to the point of needing replacement the wear and tear we put upon them is great. To expect an immediate fix with no pain is unrealistic in my eyes having suffered a back injury in 1988, fusion 1990 and now with OA, PN and chronic pain but I can walk 2 miles daily, exercise 2x a day and keep on moving. I still have a fair amount of pain and still on a narcotic for pain but I have no worries about my back. It will continue to deteriorate as I age and exercise. But if I don’t I’m a blob in pain instead of an active senior.