Wang Fengjun, who comes from Sanmenxia in Henan province, is 2.55 meters tall, 29 cm taller than Yao Ming, the former NBA basketball star.
He has been diagnosed with osteonecrosis of the femoral head, which results from an interruption of blood supply, Zhengzhou Evening News reported on Monday.
Wang said he was taller than 2 meters when he was 20. That was when he realized he had gigantism.
Wang will get free treatment in a hospital in Zhengzhou, which will exempt him from the total treatment expense of 500,000 yuan ($81,550). It is expected to take two years for Wang to recover.