Link to post not working correctly

Hey all,

I am generating links for a group of pages that have the same name as Categories using this method –

if(is_page(69) || is_array($cat) && in_array(38, $cat)){
    $categories =  get_categories('child_of=38');
    $otherService1 = get_permalink(155);
    echo '<li><h2 class="staffList_bcg_active">Individuals</h2><ul>';
    if(!empty($categories)){
        foreach ($categories as $cat) {
            $post_id = $wpdb->get_var('SELECT post_name FROM wp_posts WHERE post_title="'.$cat->cat_name.'"');
            $allLinks = '<li><a href="http://www.dynedrewett.com/'.$post_id.'">'.$cat->cat_name.'</a></li>';
            echo $allLinks;
        }
    }
    echo '</ul></li>';
    echo '<li><h2 class="staffList_bcg_normal"><a href="'.$otherService1.'">Businesses</a></h2></li>';
}

While the list dispalys correctly and the mojority of the posts work, there is one that will not link correctly. It should create the link if ‘http://www.dynedrewett.com/disputes’, but it does not and instead creats ‘http://www.dynedrewett.com/297-revision-3’, with 297 being the Post_ID and revision 3 being the latest revision. I cannot think of what chould be causing this, so any help is appricated.

Thanks.