Park has made only 20 appearances for United this season

The operation was conducted by renowned knee specialist Dr Richard Steadman in the United States.

"We couldn't get to the bottom if it. It does put an end to his season," said United boss Sir Alex Ferguson.

Park has not played since 31 March and newspaper reports suggested he could be sidelined for a year, but the club have played down those rumours.

Dr Steadman is renowned for his work with a host of sports stars.

Ronaldo, Ruud van Nistelrooy, Michael Owen and Alan Shearer are among those to have visited him, along with England cricketers Michael Vaughan and Simon Jones.