Good for you. I also did extensive PT prior to my TKRs and followed through in recovery, literally starting the same day as the surgery with a very short, PT-assisted walk in the hospital.

I'm a 69 y/o male and was bone-on-bone in both knees. The TKRs are the best thing to happen to me physically and psychologically. I was a marathoner, and even though those days are gone, I attend spin classes 2x week and row 2x week - all for cardio, and the peace of mind a great workout brings.