Materazzi has knee surgery

Inter Milan defender Marco Materazzi has undergone right knee surgery and will be out for about a month.

Inter said Friday that the arthroscopic operation was intended to fix Materazzi's meniscus.

The recipient of Zinedine Zidane's head butt in the 2006 World Cup final, Materazzi has played 41 times for Italy but his last appearance came at the 2008 European Championship.

On Wednesday, Inter lost defender Christian Chivu to a collision that resulted in skull surgery.