The defender was taken from the field on a stretcher in his side's 1-0 defeat to Southampton on February 11, after colliding with team-mate Steve Harper.
McShane underwent exploratory surgery on Monday that ruled out a micro-fracture, and is set for another operation in a fortnight.
"The operation was as good as it could be," Bruce told the club's official website.
"He had that on Monday and he'll have a major operation in two weeks' time, but the news is as good as we could have hoped for considering the damage to the ligaments.
"He hasn't got a micro-fracture so the doctor has told me, so it's as good news as we could have had, but he's still going to be out for a long time.
"He won't play again this season and we're hoping that he’ll be back for the start of next season, but until the next operation it’s still a doubt."
