Hello Twiggy!
You poor thing. Your knees sound so painful. My pain isn't as severe as yours and mostly in my spine. When my knees act up I take 1000mg Tylenol every 4 hours (doctor recommended). I put my legs up, with a rolled pillow under my knees to keep them bent and put a baby blanket, folded, around my knees to keep the heat in. It does help but it's no cure. It's also hard to get things done sitting in a chair. For my spine, I use a large ice pack for about 20 minutes or so, followed by a long heating pad for 20 minutes or so. I was amazed that it really did help. I even notice that the next day the spine is better. Until I move the wrong way and it all starts in again. My physical therapist always says "Ice, followed by heat". I laughed but she was right.
I hope you find some answers for your pain. It gets so frustrating, doesn't it? Modern medicine can replace the heart with a new one but it still can't relieve the pain of something as old as arthritis.