I Have Tried PRP Without Success At 86 I Am

I have tried PRP without success at 86 I am wary of knee replacement surgery but I need some quality of life in my remaining years. We were in the Government Heath Fund but the aged pension could not keep up with the increases. We do have a report of a CT examination of both knees which indicates that I have "advanced bilateral tricompartmental osteoarthropathy with predominant invlovment of both medial compartments" Could you please advise what the probable fees would be to replace both knee joint seperately or together