I need to have both my knees replaced. My doctor wants to do them separately. Some people have told me they've had them done at the same time and others say don't. I would also like to know what my recovery time would be if i were to have the least invasive knee replacement surgery. I am a very active 77 year old and in good health, with the exception of my knees. Don't want to be down for long. Thanks for your help. SB