After Ethics committee approval, 75 patients American Society of Anesthesiologists score (ASA) I-III were randomized at the end of surgery into 3 groups of 25 patients each who underwent femoral nerve block: group A with 20 ml ropivacaine 0,5% and 20 ml lidocaine 1%; group B with 20 ml ropivacaine 0,5%, 20 ml lidocaine 1% and 4 mg dexamethasone; group C with 20 ml ropivacaine 0,5%, 20 ml lidocaine 1% and 8 mg dexamethasone.