Under aseptic technique, all the patients will receive US-guided femoral, obturator and sciatic nerve blocks using a single puncture point. All blocks will be performed by an expert anesthetist. The femoral nerve will be blocked lateral to the femoral artery. The obturator nerve will be blocked after it exits the obturator canal (deep to pectineus muscle). While the sciatic nerve will be blocked deep (posterior) to the inferior border of quadratus femoris muscle. The motor block of the femoral, obturator and sciatic nerves and sensory block of the lateral femoral cutaneous nerve (LFCN) will be assessed before shifting the patient to the operating room.