A Comparison of US and Evoked Motor Response-guided Placement of Continuous Femoral Nerve Block Following TKA

Study Overview
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Brief Summary
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The purpose of this study is to determine which technique for catheter placement in continuous femoral nerve block (FNB) is most successful - guidance with (1) ultrasound or (2) nerve stimulation and ultrasound. Sensory and motor assessment scores will be obtained post-FNB. Patient controlled analgesia and opiate consumption is also recorded along with pain scores for the first 48 hour post-FNB.

Detailed Description
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Continuous femoral nerve block (cFNB) is a widely used regional anesthetic technique for many lower limb operations, such as total knee arthroplasty (TKA), anterior cruciate ligament repair, tibial osteotomy and patellar surgery. It provides superior pain relief, faster ambulation, shorter hospital stays and less risk of side effects in comparison to patient controlled analgesia (PCA), local anesthetic wound infiltration, or single shot femoral nerve block (FNB). Stimulating catheters were introduced in 1999 to provide an objective end point to guide continuous nerve block catheter position by maintaining the desired evoked muscle response with nerve stimulation (NS). The main advantages of stimulating catheters are faster onset of sensory and motor block and reduction of local anesthetic drugs consumption. In recent years the precise insertion of continuous catheters has improved especially with the introduction of ultrasound (US)-guided imaging to regional anesthesia practice and advances in scanning techniques. That led to a call to reduce cost by switching to non-stimulating catheters. However, most studies comparing both catheters lacked anesthetic technique standardization and adequate sample size. In this prospective randomized controlled trial, we compared postoperative analgesic efficacy and opioids consumption in patients having cFNB insertion using US alone and that of US combined with NS.

Official Title
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Comparison of Continuous Femoral Nerve Block Using Ultrasound Versus Ultrasound and Nerve Stimulation Using Stimulating Catheter in Patients Undergoing Total Knee Arthroplasty: A Prospective Randomized Controlled Trial

Conditions
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Anesthesia, Pain, Nerve Pain, Knee Arthroplasty, Nerve Block

Intervention / Treatment
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* Device: Ultrasound
* Device: Ultrasound + Nerve Stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: American Society of Anesthesiologists physical status I to III patients Aged 18-75 scheduled for unilateral TKA Exclusion Criteria: History of significant psychiatric problems BMI > 40 kg/m^2 Prior surgery in the inguinal region Neurological disease with sensory or motor deficit Diabetic neuropathy Contraindication to any study medications Daily opioid consumption >10 mg PO morphine (or equivalent) for 2 weeks prior to surgery

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Ultrasound<br>Femoral catheters inserted using ultrasound only | Device: Ultrasound<br>* Femoral catheter inserted using ultrasound only<br>|
| Active Comparator: Ultrasound + Nerve Stimulation<br>Femoral catheters inserted using ultrasound with nerve stimulation | Device: Ultrasound + Nerve Stimulation<br>* Femoral catheter inserted using ultrasound and nerve stimulation<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean numeric pain score (NRS) | Pain score assessed 24 hours post-block insertion using numeric pain scale from 0-10 | 24 hours post-block insertion | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time to perform the block | Time required to perform the block procedure | At the time of block procedure | 
| Sensation over the skin of the thigh to determine sensory block using 3 point grading scale | Sensory block evaluation examined the sensation over the skin of the thigh | 30 min post-block insertion | 
| Quadriceps muscle strength to determine motor block using 3 point grading scale | Motor block evaluation examined quadriceps muscle strength by grading the ability or inability to extend the leg of the limb to be operated on against gravity after the hip is passively flexed at 45° | 30 min post-block insertion | 
| Total hydromorphone used (oral and intravenous PCA) | Total amount of hydromorphone consumed within 24 hours post-block | 24 hours post-block | 
| Total hydromorphone used (oral and intravenous PCA) | Total amount of hydromorphone consumed within 48 hours post-block | 48 hours post-block |