Ropivacaine and levobupivacaine for bilateral selective ankle block in patients undergoing hallux valgus repair

ANKLE block anesthesia induced with long-lasting local anesthetics is commonly used for hallux valgus operations because it is safe, effective and ensures good surgical anesthesia and long post-operative analgesia (1, 2). For a complete ankle block, the standard anesthetic technique usually requires a local anesthetic volume ranging from 20 to 30 ml (3, 4). For bilateral ankle blocks, the standard technique nevertheless raises concerns about systemic toxicity (5). To avoid systemic toxicity, in patients undergoing hallux valgus repair our group has successfully used a selective bilateral ankle block technique requiring low volumes of local anesthetic injected close to the posterior tibial nerve and the deep and superficial peroneal nerves (2). Moreover, using low volumes of ropivacaine or levobupivacaine at the highest concentrations available allows us to obtain a short anesthesia onset and a prolonged post-operative analgesia; in addition, local anesthetics for block procedures can be injected with low-volume syringes that are sensitive to handle. Even though ropivacaine and levobupivacaine have been amply compared for spinal, epidural and various peripheral blocks (6), the efficacy and clinical profile of local anesthetics also depends on the type of block (5). No clinical trials have compared these two drugs in low volumes for bilateral ankle block. Using a bilateral anesthesia block as a clinical model for comparing drugs has the advantage of minimizing bias in the results from interindividual anatomical differences in the nerve courses (7). In this study, we determined the onset time and success rates for the two local anesthetics, ropivacaine and levobupivacaine, injected in low volumes for selective ankle block anesthesia in outpatients undergoing bilateral surgical repair of hallux valgus. Materials