Ultrasound Guided Femoral Nerve Block – The ultrasound (US)-guided technique of the femoral nerve block allows the practitioner to monitor the spread of local anesthetic and needle placement and make appropriate adjustments to accomplish the desired disposition of the local anesthetic. US also may reduce the risk of femoral artery puncture. Although nerve stimulation is not required for success, motor response observed during nerve stimulation often provides contributory safety information should the needle-nerve relationship be missed by US alone.