Air mattress! Up and down! Wow. I just got up and down from the floor last night (am out of town and did rehab ex on the ground) and tough to get up, and I was not even trying to be graceful!!! My second knee is 3 months now, it's going great. Not so much with long term stamina yet but day to day activities are good, swelling slight in certain areas, and, no pain meds. Rehab is also going well. I might try and get outside on a real bike over the holiday to see how that feels. I found whenever I got frustrated like you are now, suddenly poof! I had a nice improvement, and I wish that for you!!!