I used to be very active (water skiing, hiking, journeyman plumber, handy-man, lover, etc.) Now I sit at my computer play video games, take pain meds (which takes me out of the lover loop), and I wait for knee-replacement surgery. My question is this (I've been looking at alot of websites and am now totally confused). How do I (or more importantly, my doc), know what size of implant to put in my knee? Is there a regular formula docs use to measure to make sure that the knee and the implant work together? As I said, I am a (sitting on my butt), journeyman plumber, and the way things are designed to work is very important to me. I have been retrained for a new job (since after the surgery, climbing ladders and carrying 150 pound pipes is out). Is there a good website that explains knee replacement surgery and especially how the implant size is determined to fit the individual knee? Thanks for your info. Merry Christmas to you all.