Proper management of acute postoperative pain (DAPO) is essential for the recovery of orthopedic surgeries. The blockade of the femoral nerve preincisional (BFP) is simple and its effectiveness increases guided by ultrasound and neurostimulation. OBJECTIVE: To evaluate the effectiveness of BFP in patients undergoing orthopedic surgery of the lower limbs under general anesthesia. METHODS: A comparative study was conducted, randomized, two groups, surgeries of the hip, femur and knee, ASA I-II, aged 18 years. Group B (n = 15) received BFP and ultrasound-guided nerve stimulation with 20 ml of bupivacaine 0.5% plus epinephrine 1: 200,000. Group S (n = 15) without blocking. Both groups received intravenous analgesia with ketoprofen 100 mg regimen and dipyrone 1g c / 8 hs and balanced general anesthesia. Postoperative morphine 0.03 mgr / kgr / weight was administered if EVA ≥4