what i do to avoid this is use the two options at the top.
every time i sign in, i look at the "Show new replies to your posts." page, and answer appropriately.
then i check the "Show unread topics since your last visit." page. I would suggest clearing this list and starting over, but its your choice if you want to sift through 10 pages of crap. (or maybe not, i don't know. >_<)
and thats how i avoid bumping old shit.