To compare the use of ropivacaine versus bupivacaine for 3-in-1 block during total knee arthroplasty (TKA) in terms of efficacy and safety (lack of toxicity).
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. The dosage was 0.5 ml/kg. In addition, a sciatic nerve block (20 ml of prilocaine 1%) was used. The onset of the block, duration of postoperative analgesia, level of motor block, and any side-effects were compared.
The median time to onset of block was significantly shorter in those receiving ropivacaine than bupivacaine (13 vs. 17.5 minutes, p<0.001), but the levels of motor blockade were not significantly different (p=0.355). Complete analgesia was achieved throughout the procedure. There was no significant difference between the ropivacaine and bupivacaine groups in terms of the mean duration of analgesia (398 vs. 367 minutes, p=0.62), the mean VAS scores at all time points, and the mean total morphine consumption. One patient in the ropivacaine group developed a joint haematoma and 2 patients in the bupivacaine group had excessive wound drainage. Both conditions resolved after antibiotic use.
Ropivacaine and bupivacaine showed similar anesthetic and analgesic effects, but the former had a significantly faster onset time.