Rome - AC Milan midfielder Gennaro Gattuso underwent surgery in Antwerp, Belgium, to repair a damaged knee tendon, the club's web site reported on Monday.

Orthopaedic surgeon Marc Martens operated on Gattuso's right knee to rebuild a damaged cruciate ligament.

"The operation was successful. Recovery time is expected to be about six months," Milan said.

The 30-year-old world champion twisted his joint during a league match against Catania on December 7 and will be out for the rest of the season. (dpa)