Hi, @jamessaxo. Running without pain at 83 is incredible! I salute you. How much running do you do? My right knee is already a TKR. I had that installed … oh, 20-25 years ago, when my ortho doc slapped my X-ray on his lightbox and said, "You see, Ray: bone-on-bone." My TKR doesn't give me any trouble; never has. My left knee's overload of arthritis is largely the result of the insane amount of running I used to do. I was training for another ultra marathon when I said, "Stop being stupid, Ray. Get another hobby. How about readinng? Or chess?" 🙂 All my best to you, @jamessaxo! –Ray (@ray666)