The England hooker, 28, went off on a stretcher after tackling Broncos half-back Anthony Milford.
Wane said the operation "went well" but added: "I can't see him playing again this year."
McIlorum has played 220 games for the Warriors, winning two Grand Finals and a Challenge Cup.
Wigan coach Shaun Wane says Michael McIlorum will miss the rest of the year after suffering a broken ankle in the World Club Series defeat by Brisbane.