I had my right knee replaced two years ago. It is now my good knee. The important thing is doing the post-op exercises and getting the physical therapy. My knee is still getting stronger. I run about two gears higher on the hills on my commute than a year ago. Still working and riding to work at 66. My other knee has moderate arthritis that flares up if I don't ride about 3-4 times a week. If I ride, it feels pretty good.