Duration of analgesia was the shortest with mepivacaine ( 4.9 2.4 hours ) , longest with bupivacaine ( 14.0 6.2 hours ) , and intermediate with the combination group ( 10.3 4.9 hours ) ( P < 0.001 for mepivacaine vs. combination group ; P = 0.01 for bupivacaine vs. combination group ) .
