107 patients undergoing arthroscopic anatomic single-bundle anterior cruciate ligament (ACL) reconstruction were randomized to receive an administration of either magnesium in conjunction with levobupivacaine, or levobupivacaine only to evaluate the effects on clinical outcomes and pain. The results indicated that magnesium, in conjunction with levobupivacaine, provided improvements in Visual Analog Scale (VAS) pain scores, Verbal Rating Scale scores, the amount of postoperative rescue analgesics, total opioid consumption and block onset time. However, it also increased the time to first mobilization compared to the levobupivacaine-only group. Lastly, there were no differences in the side-effects observed between the two groups.