In 1 month , 3 months and 6 months postoperatively , the proportion of normal BUT increased respectively in both groups ( simple resection group :8 / 16 , 9/16 , 10/16 ; resection and fixation group :8 / 17 , 10/17 , 11/17 ) compared with that before operation ( simple resection group :3 / 16 ; resection and fixation group :4 / 17 ) .