Sumo grand champion Hakuho underwent successful endoscopic surgery on his right knee at a hospital in Tokyo on Thursday, sources close to his Miyagino stable said.

Hakuho, who won last month's Autumn Grand Sumo Tournament with a perfect 15-0 record, was forced to withdraw from an ongoing regional tour due to pain in his right knee. He underwent the procedure to remove a bone chip that was causing the pain.

Stablemaster Miyagino, who is scheduled to see Hakuho on Friday, said he will discuss with the 33-year-old Mongolian whether he can compete at the Kyushu Grand Sumo Tournament next month.

At last month's Autumn meet, Hakuho became the only wrestler to win 1,000 bouts in the sport's top division. But he has struggled with injuries this year, withdrawing from three of the five tournaments held so far.