Two replacements at once is scarey,at least for me. I manufactured hip and knee replacement parts way back in the 70's. We worked with the Drs. and Engineers in producing the right size for the individual receiving the transplant. The materials used back then were titanium and chrome colbolt. Ceramic came along later and I understand it is best.

Like you my knees are to the point of replacing,just waiting it out I hate surgery. Good Luck and prayers for the Misses.