Adductor Canal Block Versus Femoral Block on Pain and Quadriceps Strength

Study Overview
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Brief Summary
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The purpose of this study is to compare the effects of a femoral nerve block vs. an adductor canal block on pain and quadriceps muscle strength for knee arthroscopy surgery.

Detailed Description
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Patients undergoing arthroscopic knee surgery (ACL and non-ACL surgery) typically receive an ultrasound-guided femoral nerve block or an adductor canal block in the pre-operative phase for post-operative pain control. While an effective method for post-operative analgesia, the femoral nerve block is associated with profound quadriceps weakness for the duration of the nerve block, which can impair ambulation, rehabilitation, and increase the risk of falls. The more distal adductor canal block, however, contains primarily sensory branches of the femoral nerve and has been been purported by small volunteer studies to provide equally effective analgesia with minimal motor block and quadriceps weakness (as compared to femoral nerve block). The investigators will prospectively randomize patients undergoing knee arthroscopy at the UCSF Orthopaedic Institute to receive either a single-shot femoral nerve or adductor canal block pre-operatively after taking baseline measurements of quadriceps strength (quantified by maximum voluntary isometric contraction). The quadriceps muscle strength will be checked 20 minutes after the nerve block to assess strength. All patients will subsequently undergo a general anesthetic. The primary outcome variable will be post-block quadriceps strength as a percentage of baseline from pre-block values. Secondary outcome variables that will also investigated include: VAS pain score in the post anesthesia recovery unit and post-operative day 1, time to onset of sensory block, duration of nerve blockade, block performance time, patient satisfaction score, perioperative opioid use, perioperative analgesic consumption, incidence of paresthesias, number of needle passes, incidence of post-operative nausea, vomiting, constipation, and any other complications.

Official Title
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Effects of Ultrasound-guided Adductor Canal Block Versus Femoral Nerve Block on Pain and Quadriceps Strength After Ambulatory Knee Arthroscopic Surgery

Conditions
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Anterior Cruciate Ligament Tear, Knee Meniscus Tear

Intervention / Treatment
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* Procedure: Femoral Nerve Block
* Procedure: Adductor Canal Nerve Block
* Drug: preoperative Femoral Nerve Block using 20ml of 0.5% ropivacaine
* Drug: Preoperative Adductor canal block with 0.75%% ropivacaine 13.3ml.


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: American Society of Anesthesia I-III classification, Scheduled for arthroscopic knee surgery (meniscal debridement/repair, ACL reconstruction) Exclusion Criteria: Age younger than 18 years Non-English speaking Any contraindication for regional anesthesia, such as allergy to local anesthetics or opioids, -Coagulopaty or severe thrombocytopenia Infection at puncture sites Pre-existing neuropathy in operative limb Need for post-operative nerve function monitoring Dementia Patient refusal High pre-operative opioid requirements

Ages Eligible for Study
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Minimum Age: 18 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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Femoral Block<br>Patients scheduled for knee arthroscopy will have a femoral nerve block done using 0.5% ropivacaine 20ml before surgery. | Procedure: Femoral Nerve Block<br>* Patients having ACL reconstruction, meniscus surgery and knee arthroscopy<br>Drug: preoperative Femoral Nerve Block using 20ml of 0.5% ropivacaine<br> <br> |
| Experimental: Adductor Canal Block<br>Patients scheduled for knee arthroscopy will have an adductor canal block done using 0.75% ropivacaine 13.3ml before surgery. | Procedure: Adductor Canal Nerve Block<br>* Patients having ACL reconstruction, meniscus surgery and knee arthroscopy<br>Drug: Preoperative Adductor canal block with 0.75%% ropivacaine 13.3ml.<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in quadriceps strength related to the nerve block | Quadriceps strength will be tested with a dynamometer before the nerve block and 20 minutes after the nerve block prior to surgery. We are trying to measure the effect of both femoral and adductor canal nerve blocks on quadriceps strength. | Baseline and 20 minutes after the block prior to surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Numerical Pain score from 0-10 | As this is an outpatient surgery, we will collect Numerical Pain Scores from the recovery room medical record after surgery as well as from the patients for the first 24 hours after surgery by contacting them at home the following day. We will evaluate the difference in patient pain scores between the two nerve blocks under study | up to 24 hours | 
| Duration of nerve block | Patients will be contacted after surgery to determine when the nerve block wore off based on their increase in pain | 8 to 24 hours | 
| Opioid Consumption reported at mg of morphine equivalence | Data on the amount of pain medication consumed for the 1st 24 hours after surgery will be collected based on medications that were administered during surgery, in the recovery room and medications that patients took at home after discharge from the recovery room. All pain medications will be converted to morphine equivalence in milligrams and reported that way. The comparison will be the difference in mg morphine equivalence consumption between the two nerve block groups. | 2 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Knee arthroscopy, ACL reconstruction, Femoral block, Adductor Canal Block