I'm glad to hear ye old knees are good, I'm tempted to give you a thumbs up, but I guess that wouldn't be a good idea and it would be stupid humour....;-)
Heck , I'll take good knees myself, I'll let you know in 13 years or so. I've whacked my right knee a few times with ski and motorcycle falls in my youth, so it talks to me sometimes if im not respectful of it or lack being active for a while.