Using preg_replace to replace title in anchor links

I am trying to use some regular expressions to change out the titles in some links.

I have these links:

<a class="postlink" href=""></a>

That I want to change to:

<a class="postlink" href="">ESPN: The Worldwide Leader In Sports</a>

I have the function created to grab the url title block, but I can’t figure out how to replace the url with the title.

Any suggestions?

$link = '<a class="postlink" href=""></a>';
$newTitle = 'ESPN: The Worldwide Leader In Sports';
$newLink = preg_replace('#(<a.*?>)[^>]*(</a>)#s', '${1}'.$newTitle.'${2}', $link);

Trying to use Regular Expressions for this would be very very unreliable.

$doc = new DOMDocument;
$doc->loadHTML( $html );

$xp = new DOMXPath( $doc );
foreach ( $xp->query( '//a[@class="postlink"]' ) as $link ) {
  // Get title here and stuff...
  $text = "SuperLink: " . $link->textContent;

  $link->removeChild( $link->firstChild );
  $link->appendChild( new DOMText( $text ) );

echo $doc->saveHTML();