Owen Hargreaves will miss the rest of the season following a successful operation on his right knee.

The midfielder will also undergo surgery on his left knee in a few weeks' time under the guidance of knee specialist Richard Steadman in Colorado.

United boss Sir Alex Ferguson told MUTV: "He had the operation on Monday and it went well, although we won’t know the exact details until he gets back. He has to have a further operation on his left knee in a few weeks.

"The reason for us sending him out to America was because Richard is a first-class specialist who deals with these sorts of injuries, and Owen's own preference was to be in Colorado.

"Unfortunately he is out for the season, but we hope this will now be put to bed and we’ll get him back as a fit player for the start of next season."

Hargreaves has endured a frustrating time at United since arriving last summer.

He missed the start of the 2007/08 campaign but he played a prominent role in United's Double charge after Christmas.

However, the 27-year-old's tendonitis flared up again in pre-season and he has made only three appearances this term.