14 men and 26 women aged 58 to 77 ( median , 70 ) years who had the American Society of Anesthesiologists ( ASA ) grades I to III physical status were randomised to receive ropivacaine ( n = 20 ) or bupivacaine ( n = 20 ) of a concentration of 0.5 % for 3-in-1 block during TKA .