Adductor Canal Block Versus Femoral Block on Pain and Quadriceps Strength

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

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.

Study Overview

• Status: Completed
• Conditions: Anterior Cruciate Ligament Tear; Knee Meniscus Tear
• Intervention / Treatment: Procedure: Femoral Nerve Block; Drug: preoperative Femoral Nerve Block using 20ml of 0.5% ropivacaine; Procedure: Adductor Canal Nerve Block; Drug: Preoperative Adductor canal block with 0.75%% ropivacaine 13.3ml.

Detailed Description

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, duration of nerve blockade, and perioperative opioid consumption.

• Study Type: Interventional
• Enrollment (Actual): 132
• Phase: Phase 4

Contacts and Locations

Study Locations

• United States
  • California
    • San Francisco, California, United States, 94158
      • UCSF Orthopedic Trauma Service

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

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

What is the study measuring?

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. The dynamometer measures the strength of the quadriceps muscles in the seated position while pushing against the device. 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. The highest pain score for the 24-hour post-op period was collected for each participant. The median is reported for all participants. A pain score of 10 represents the worst pain.	worse pain in first 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

Collaborators and Investigators

• Sponsor: University of California, San Francisco
• Investigators: Principal Investigator: Pedram Aleshi, MD, University of California, San Francisco

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2016
• Primary Completion (Actual): March 20, 2022
• Study Completion (Actual): March 20, 2022

Study Registration Dates

• First Submitted: November 16, 2021
• First Submitted That Met QC Criteria: January 12, 2022
• First Posted (Actual): January 13, 2022

Study Record Updates

• Last Update Posted (Estimated): September 30, 2025
• Last Update Submitted That Met QC Criteria: September 16, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: ACL reconstruction; Adductor Canal Block; Knee arthroscopy; Femoral block
• Additional Relevant MeSH Terms: Wounds and Injuries; Leg Injuries; Knee Injuries; Anterior Cruciate Ligament Injuries; Organic Chemicals; Anilides; Amides; Aniline Compounds; Amines; Ropivacaine
• Other Study ID Numbers: 14-13071

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: IPD will be shared only if required for the publication of data.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No