Anagram, it's interesting, I think, to watch our reactions to others' ideas about our weight or weight loss. For example, I've noticed recently that when I meet someone new who didn't know me when I was heavy, and they comment on how thin I am, I always feel compelled to tell them that I've lost nearly 50 pounds instead of just accepting the compliement and letting it go at that. It always floors me when I do that too, like WHY do I do that?! And if the person who's compliemented me is heavy, then I really want to dig in and tell them I used to weigh more, that I just didn't pop put of the box like this!
The woman you're talking about probably commented because she really does know what it takes to lose weight, knows how challenging it is. I'm sure she wasn't aware of your knee replacements---I think that's the part that would bother me if I were in your shoes. To think that your weight was affecting the way you walk--I would've had to set her straight on that one! Don't let it nag at you--sounds like an overall compliement to me!