function getTrunc($n, $l) {
    if (!isset($n{$l}) { return $n; }
    $n = explode(' ', substr($n, 0, $l));
    if (count($n)>1) { unset($n[count($n)-1]); }
    return implode(' ', $n).'...';
}

your checking the size before its exploded, getTrunc(12345,2) will return 12345 instead of 12