给关羽刮骨疗毒的不是华佗，因为华佗死于建安十三年(公元208年)，而关羽被毒箭所伤是在建安二十四年(公元219年)，也就是华佗去世后的十一年。根据三国志记载，医曰：“矢镞有毒，毒入于骨，当破臂作创，刮骨去毒，然后此患乃除耳。”
It was not Hua Tuo who scraped Guan Yu’s bones to cure poison, because Hua Tuo died in the 13th year of Jian’an (208 AD), and Guan Yu was injured by a poisonous arrow in the 24th year of Jian’an (219 AD), that is, Hua Tuo Eleven years after his death. According to the records of the Three Kingdoms, the doctor said: “Arrowheads are poisonous, and the poison enters the bone. When the arm is broken, the bone is scraped to remove the poison, and then the disease is removed.”
So there is indeed a case of bone scraping to treat poison, but there is no specific record of which doctor it is.
所以确实有刮骨疗毒这件事，但是并没有具体记载是哪一位医生。