query_posts and sticky posts problem

Hi folks, I have problem with query_posts command and sticky posts. I am using custom twentyten child theme and in themes index.php I inserted this code
if ( is_home() ) {query_posts($query_string.'&cat=3');}
so only one category is on the front page. So my problem is when I make post sticky nothing happens. Post remains on it’s place.
I tried removing that code and then it was OK. But i need this because I want to show only one category on front page. Does anybody have a solution for my problem? Thanks