My sister rode her stationery bike every day for a long time before her knee surgery, and I think she had a lot less pain after surgery than I did. She was also able to get back on the bike and pedal all the way around a lot sooner than I could post-surgery. Since the bike is one of the main exercises after the surgery, I think it makes a lot of sense to build up the muscles above and below your knee by using the bike before surgery.
My best friend who is extremely overweight found it very helpful to work on her upper body strength before surgery, because having strong arms made it a lot easier for her to move in and out of the bed, onto the massage table, etc., after the surgery.
I personally didn't do much before the surgery, but wish I had done both of these things--the bike and upper body!
Best of luck to you,
Sue