Comparison of 3 Techniques for Ultrasound-guided Femoral Nerve Catheter Insertion

Comparison Between Ultrasound Guided Femoral Nerve Block Versus Ultrasound Guided Femoral Nerve Block With the Use of Peripheral Nerve Stimulation for Patients Undergoing Total Knee Replacement.

This is a randomized study which will compare three femoral nerve catheter insertion techniques. Subjects will be randomized into one of thee groups, Group 1: ultrasound guided femoral nerve catheter using a stimulation needle and stimulating catheter, .Group 2: ultrasound guided femoral nerve catheter using a stimulation needle, but non-stimulating catheter, or Group 3: ultrasound guided femoral nerve block without stimulation.

This is a randomized study which will compare three femoral nerve catheter insertion techniques. Subjects will be randomized into one of thee groups, Group 1: ultrasound guided femoral nerve catheter using a stimulation needle and stimulating catheter, .Group 2: ultrasound guided femoral nerve catheter using a stimulation needle, but non-stimulating catheter, or Group 3: ultrasound guided femoral nerve block without stimulation.

• Pain Scores after surgery with be measured using the VAS (Visual Analogue Scale). Subjects will be asked to rate their pain on a scale of 1-10.
• Block Performance time is the time from starting the block (after prepping and draping) until catheter is placed.
• Opioid requirements will be measured as the total amount of opioids (converted to morphine sulfate equivalents) used both during surgery, and during the first 48 hours after surgery.
• Block failure rate will be calculated as the rate of cases that requires repeating the block after surgery.

Inclusion Criteria:

• 18 to 80 years old at time of surgery.
• Male or female patients undergoing total knee replacement under either general or neuraxial anesthesia (spinal or epidural). Intraoperative, patients will receive spinal anesthetics with 15 mg bupivacaine and 25mcg of fentanyl intrathecally.

Exclusion Criteria:

• Current or recent drug abuse (within past 6 months).
• Pregnancy.
• Patient refuses regional analgesia.