There have been suggestions if surgery does not prove successful for the Calgary-born midfielder he will be forced to retire from the game.
However, Ferguson reports the operations have gone well, allowing Hargreaves to begin a long recovery programme that should get him back on the pitch again by August.
"Owen had a second operation last week and it was completely successful," said the United manager.
"It was better than the last one, which was much more difficult.
"This one is completely clear and I am certain he will be ready for the start of next season."
Hargreaves has been restricted to just three appearances this season and has not been on first team duty since the draw at Chelsea in mid-September.