RecruitingPhase 4NCT06784882

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

Sponsor

University of California, San Diego

Enrollment

40 participants

Start Date

Jun 1, 2025

Study Type

INTERVENTIONAL

Conditions

acute postoperative pain Surgery

Summary

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.

Eligibility

Min Age: 18 Years

Inclusion Criteria4

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

Exclusion Criteria10

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

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Interventions

DEVICEcontinuous 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.

DRUGsingle 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.