Wayne,
My knee has needed replacing for over 3 decades and it's finally to the point that it cannot be ignored. High school football injury started it. Dirt bike pile up, running hair scrambles screwed it. Partial frag grenade ingredients in it as well.
I am now "out 23 1/2 degrees" and it has been bone-on-bone for longer than I can remember. Believe me: It needs replacin'.
Thanks, Capt. Chris