Arsenal defender Per Mertesacker has undergone surgery on his ankle injury and will be out "long term", according to manager Arsene Wenger.

Mertesacker: Needs surgery

Mertesacker suffered ligament damage during Saturday's 2-1 victory at Sunderland and could be sidelined for the rest of the season.

"Unfortunately he has had surgery and we have lost him for a while," Wenger told the club's official website, www.arsenal.com.

"How long I don't know. He had reconstruction of his ligaments, so it will be long term."