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

Not Applicable

Completed

Brief Summary: 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: 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.

Recruitment & Eligibility

Inclusion Criteria

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

Arm && Interventions

Group	Intervention	Description
Ultrasound	Ultrasound	Femoral catheters inserted using ultrasound only
Ultrasound + Nerve Stimulation	Ultrasound + Nerve Stimulation	Femoral catheters inserted using ultrasound with nerve stimulation

Primary Outcome Measures

Name	Time	Method
Mean numeric pain score (NRS)	24 hours post-block insertion	Pain score assessed 24 hours post-block insertion using numeric pain scale from 0-10

Secondary Outcome Measures

Name	Time	Method
Sensation over the skin of the thigh to determine sensory block using 3 point grading scale	30 min post-block insertion	Sensory block evaluation examined the sensation over the skin of the thigh
Quadriceps muscle strength to determine motor block using 3 point grading scale	30 min post-block insertion	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°
Time to perform the block	At the time of block procedure	Time required to perform the block procedure
Total hydromorphone used (oral and intravenous PCA)	48 hours post-block	Total amount of hydromorphone consumed within 48 hours post-block

Locations (1): Sunnybrook Health Sciences Centre
🇨🇦
Toronto, Ontario, Canada

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