@rosiegirl I am really sorry to hear of the problems you having with your knee. I was in a lot of pain for about four weeks and around then it started improving and I was great at the six-week mark.
For you to have this much pain still really does not sound right. Have you sought a second opinion? I think I would do that if I had that much pain, preferably one from a really top ortho at an excellent medical center. I have no idea if having sciatica could contribute to your pain or now, that is not a problem I have had.
As @colleenyoung mentioned, I am a huge advocate of water exercise, and also the recumbent bike. When I was talking to my ortho I asked him about the best exercises and coincidentally these are two of the exercises he considers best also. I continue to do both of those but now I also do other exercises in the gym at my health club.
I really hope you find a top doctor to get a second opinion from. You should not have to deal with this much pain for so long.
JK