i am in the same boat. Had TNR 11 years ago. Still painful. Surgeon says its phantom pain. Yea, right. The other knee i do PRP every year. Yes, its expensive. As i am in my 80's i get the full dose and i can still bike, play golf and garden. I can get on that knee to garden. What PRP does is goes after the arthritis. It also grows hair for women. It works for me. I would rather pay the out of pocket than go thru the 3 month painful rehab that i had with TKR. I wish i had a do over on that knee.