The complex knee surgery has been associated with severe postoperative pain. Different analgesic techniques for postoperative management of this increasingly common surgery, with main purpose of adequately control pain, minimizing adverse effects and seeking early rehabilitation.~Currently, the most used technique is the continuous femoral nerve block, which is able to control postoperative pain well, but has the limitation that also produces motor blockade, decreasing quadriceps strength up to 80%, increasing the number of falls and delaying early mobilization after surgery. On the other hand, the adductor canal nerve block is an alternative as it is considered a purely sensitive block. The nerves that are in this channel are the saphenous adductor nerve, posterior branches of the obturator nerve, medial vast nerve, sometimes the medial cutaneous nerve and anterior branches of the obturator nerve and the vast medial nerve.~With regard to the adductor canal block, current literature supports analgesic effect comparable to femoral nerve block with less motor block than femoral nerve block. However, there is no clarity regarding the ideal concentration and volume of local anesthetics to use. Volumes ranging from 5 to 30 ml have been used in different studies. For example, using 20 mL of local anesthetic in femoral nerve block has produced scattering of anesthetic that has blocked motor branches.~The investigators objective is to determine which volume of levobupivacaine 0.25% is necessary to produce analgesia and sensitive blockade while minimizing motor blockade in adductor canal nerve block in patients undergoing cruciate ligament reconstruction surgery.
To establish adequate volume of levobupivacaine 0.25% in adductor canal nerve block in unilateral cruciate ligament of the knee reconstruction surgery.