Patient Position: Lateral with the operative side up.

Indications: Anesthesia and immediate postoperative analgesia for major knee surgery, hip arthroplasty, femoral neck fracture surgery, and any surgery performed in the territory of the femoral and lateral cutaneous nerves.

Needle Size and Catheter: 18-gauge, 100-mm insulated Tuohy needle and 20-gauge catheter.

Volume and Infusion Rate: 30 mL 0.5% ropivacaine (anesthesia), 15 to 20 mL ropivacaine 0.2% followed by an infusion of 6 to 8 mL/hour 0.2% ropivacaine (postoperative analgesia).

Anatomic Landmarks: The superior border of the posterior iliac crest and the spinous process of L4-L5.

Approach and Technique: A vertical line is drawn at the level of the superior border of the posterior iliac crest. Next a horizontal line is drawn at the level of the spinous process of L5-L4. The site of introduction of the needle is 5 cm above the spinous processes on the bisiliac line. The needle, with the bevel oriented cephalad, is introduced perpendicular to the skin in the direction of the transverse process. The needle is then walked cephalad off the transverse process until a stimulation of the femoral nerve is elicited. The position of the needle is adjusted to produce a motor response with a current less than 0.5 mA (Fig. 28-1). After negative blood aspiration, local anesthetic solution is slowly injected. The injection is followed by the placement of a catheter introduced 3 to 5 cm beyond the needle tip. The catheter is secured and covered with a transparent dressing.