Sherry,
Speaking as someone with two arthritic knees, anything that affects your gait can add to the wear and tear on your knees. When I hurt my first knee, that made me walk funny, which probably didn't do the other knee any good, then I hurt the good knee. OK, maybe I just have bad genes, but I do know when I limp, my knees hurt worse.
I think that thigh atrophy and tight calf muscle would definitely pull things out of their normal position, causing extra wear and tear.