Elgey, who was the club’s rookie of the year in 2015, suffered the devastating knee injury in the first training session of the year.
The 21-year old made his NRL debut last year and scored six tries in 16 matches. Elgey was expected to play a key role for the Titans this season.
“It’s a devastating blow for Kane and he has naturally taken it hard,” Gold Coast head coach Neil Henry said.
“He showed his immense promise during his rookie season in 2015 and had been training extremely well, always among the leading group, and shown what great strides he had taken in confidence and maturity.
“We all really feel for him, Kane is such a popular and hard-working part of the group.
“But he is young and determined and he will overcome this setback and come back and continue to progress into a quality NRL player.
“Kane emerged quickly last season after being given his chance through injury to Dan Mortimer.
“Ash Taylor succeeded Kane as the Holden Cup player of the year and has the chance to make his mark in 2016.
“We are determined to overcome this and I’ve been very impressed with the group resolve and attitude of the squad during the pre-season.”