Continuous Versus Single Injection Adductor Canal Blocks for Outpatient Total Knee Arthroplasty

A Pilot Randomized Controlled Trial Assessing Pain and Opioid Outcomes Among Patients Undergoing Total Knee Arthroplasty Receiving 5-Day Outpatient Adductor Canal Continuous Versus Single Injection Blocks

This is a single-center pilot study to determine if an adductor canal continuous nerve block is superior to single injection nerve block following total knee arthroplasty. Investigators will randomize participants to either continuous nerve block or single injection nerve block for the adductor canal preoperatively. They will assess differences in pain (measured in numeric rating scale), opioid consumption, and physical therapy milestones from postoperative day 0 to 7.

Study Overview

• Status: Recruiting
• Conditions: Surgery; Acute Postoperative Pain
• Intervention / Treatment: Device: continuous peripheral nerve block with OnQ pump; Drug: single injection nerve block

Detailed Description

Adductor canal blocks are standard care for postoperative analgesia following total knee arthroplasty. Adductor canal blocks involve depositing local anesthetic (ropivacaine) around the saphenous nerve at the location of the adductor canal on the ipsilateral thigh. At UCSD, the standard care is to perform single injection adductor canal blocks for research participants undergoing total knee arthroplasty prior to surgery in the preoperative waiting area.

Participants will be randomized to either: (1) single injection with ropivacaine (0.5%) of the adductor canal block AND a 5-day continuous perineural infusion of ropivacaine (0.2%) (experimental group); versus (2) single injection with ropivacaine (0.5%) of the adductor canal block and no continuous nerve block added.

• Study Type: Interventional
• Enrollment (Estimated): 40
• Phase: Phase 4

Contacts and Locations

• Study Contact: Name: Rodney A Gabriel, MD; Phone Number: 858-663-7747; Email: ragabriel@health.ucsd.edu

Study Locations

• United States
  • California
    • La Jolla, California, United States, 92037
      • Recruiting
      • University of California, San Diego
      • Contact: Rodney Gabriel; Phone Number: 8586637747; Email: ragabriel@health.ucsd.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Adult participants of at least 18 years of age
2. Undergoing a primary, unilateral, total knee arthroplasty
3. Planned single-injection adductor canal nerve block
4. Weight > 50 kg (to minimize the risk of local anesthetic toxicity)

Exclusion Criteria:

1. chronic opioid or tramadol use: daily oxycodone equivalents > 20 mg for > 4 weeks
2. neuro-muscular deficit of the surgical limb
3. moderate pain (NRS > 3) in an anatomic location other than the surgical site
4. planned hospital admission following surgery
5. history of opioid misuse
6. those who lack capacity to complete informed consent
7. inability to contact the investigators during the treatment period, and vice versa (e.g., lack of telephone access)
8. incarceration
9. pregnancy
10. allergy to amide local anesthetics

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Continuous adductor canal block; single injection with ropivacaine (0.5%) of the adductor canal block and a 5-day continuous perineural infusion of ropivacaine (0.2%) (experimental group)	Device: continuous peripheral nerve block with OnQ pump; For continuous nerve blocks, the infusion pump that will be used are OnQ pumps (Avanos, Alpharetta, GA) and pre-filled with ropivacaine 0.2% and provided by UCSD's Investigational Drug Services.
Active Comparator: single injection adductor canal block; single injection with ropivacaine (0.5%) of the adductor canal block and no continuous nerve block added	Drug: single injection nerve block; An adductor canal single injection nerve block will be performed per standard of care. The adductor canal will be identified by ultrasound in the short-axis view. The distal aspect of the femoral triangle (and beginning of the adductor canal) will be identified distal to the mid-thigh in the ipsilateral limb. Using ultrasound guidance, a standard Tuohy block needle will be advanced through a skin wheal of lidocaine until its tip is in the hypoechoic area immediately distal saphenous nerve adjacent to the femoral artery. Twenty milliliters of ropivacaine 0.5% will be injected in divided doses with repeated negative aspiration.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
analgesic effect of 5-day continuous nerve block of the adductor canal relative to a single inection nerve block with ropivacaine.	Numeric Rating Scale (NRS) for pain will be superior daily with continuous adductor canal blocks on postoperative days 1-7 following total ankle arthroplasty as compared with single-injection adductor canal blocks (as measured by the "average" daily NRS within the Brief Pain Inventory)	7 days
opioid consumption of 5-day continuous nerve block of the adductor canal relative to a single inection nerve block with ropivacaine.	Opioid consumption will be superior daily with continuous adductor canal blocks on postoperative days 1-7 following total ankle arthroplasty as compared with single-injection adductor canal blocks (measured in oxycodone equivalents)	7 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
physical and emotional functioning of 5-day continuous nerve blocks relative to a single injection nerve blocks with ropivacaine	The physical and emotional functioning of research participants will be superior daily with continuous adductor canal blocks on postoperative days 1-7 following total ankle arthroplasty as compared with single-injection adductor canal blocks (as measured with the Brief Pain Inventory Interference Subscale)	7 days
improvement in physical therapy milestones of 5-day continuous nerve blocks relative to a single injection nerve blocks with ropivacaine	Knee injury and osteoarthritis outcome score for joint replacement (KOOS JR)	30 days
30-day pain score measured in Numeric Rating Scale	At around 30 days postoperatively, the patients average pain score measured in the numeric rating scale (0-10) will be assessed.	30 days
30-day postoperative opioid consumption	Around 30 days postoperatively, the average opioid consumption will be assessed. This will be based on the average opioid consumption over the preceding week at 30 days.	30 days

Collaborators and Investigators

• Sponsor: University of California, San Diego

Publications and helpful links

General Publications

• Chou R, Gordon DB, de Leon-Casasola OA, Rosenberg JM, Bickler S, Brennan T, Carter T, Cassidy CL, Chittenden EH, Degenhardt E, Griffith S, Manworren R, McCarberg B, Montgomery R, Murphy J, Perkal MF, Suresh S, Sluka K, Strassels S, Thirlby R, Viscusi E, Walco GA, Warner L, Weisman SJ, Wu CL. Management of Postoperative Pain: A Clinical Practice Guideline From the American Pain Society, the American Society of Regional Anesthesia and Pain Medicine, and the American Society of Anesthesiologists' Committee on Regional Anesthesia, Executive Committee, and Administrative Council. J Pain. 2016 Feb;17(2):131-57. doi: 10.1016/j.jpain.2015.12.008.

Study record dates

Study Major Dates

• Study Start (Actual): June 1, 2025
• Primary Completion (Estimated): December 1, 2025
• Study Completion (Estimated): December 1, 2025

Study Registration Dates

• First Submitted: January 11, 2025
• First Submitted That Met QC Criteria: January 15, 2025
• First Posted (Actual): January 20, 2025

Study Record Updates

• Last Update Posted (Actual): June 17, 2025
• Last Update Submitted That Met QC Criteria: June 12, 2025
• Last Verified: June 1, 2025

More Information

Terms related to this study

• Keywords: nerve block; total knee arthroplasty; regional anesthesia
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Postoperative Complications; Pathologic Processes; Pain, Postoperative
• Other Study ID Numbers: 811228

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: Yes