NORTH Melbourne forward Nathan Thompson has undergone arthroscopic surgery in a bid to determine the latest problem with his troublesome left knee.
Thompson, 30, missed the Kangaroos' recent clash with Geelong after jarring the knee he had reconstructed at the start of last season in round 10 against the Brisbane Lions.
The club issued a statement on Thursday night revealing the former Hawk had the exploratory surgery on Wednesday evening, with assessment next week to determine exactly how long he'll be out this time around.
Thompson previously said he hoped he was suffering from just "inflammation" following the Gabba match, after playing with soreness for "most weeks" this year.
He returned from the season-ending knee injury he sustained in a practice match in 2007 in round one this year, and kicked 24 goals in the first10 games.
