Preg_replace

Hi i’m having a preg_replace problem.

I have a variable :
$word

This variable comes from a link someting like:
<a href=".$PHPSELF."?word=milk>milk</a>

Now i want to replace all:
<a href=".$PHPSELF."?word=$word>$word</a>

With:
$word

so infact i’m unlinking the word that is the variable can anyone help me with this cause I don’t understand the symbols i can use within the pre_replace function?

Thanks in advance