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

Phase 4

Not yet recruiting

• Conditions: Acute Postoperative Pain; Surgery
• Interventions: Device: continuous peripheral nerve block with OnQ pump; Drug: single injection nerve block

• Registration Number: NCT06784882
• Lead Sponsor: University of California, San Diego

Brief 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.

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 Timeline

• Status Verified: 2025-01
• Study First Submitted: 2025-01-11
• Study First Submitted QC: 2025-01-15
• Last Update Submitted: 2025-01-15
• Study First Posted: 2025-01-20
• Last Update Posted: 2025-01-20
• Study Start: 2025-02-01
• Primary Completion: 2025-12-01
• Study Completion: 2025-12-01

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 40

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 & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Continuous adductor canal block	continuous peripheral nerve block with OnQ pump	single injection with ropivacaine (0.5%) of the adductor canal block and a 5-day continuous perineural infusion of ropivacaine (0.2%) (experimental group)
single injection adductor canal block	single injection nerve block	single injection with ropivacaine (0.5%) of the adductor canal block and no continuous nerve block added

Primary Outcome Measures

Name	Time	Method
analgesic effect of 5-day continuous nerve block of the adductor canal relative to a single inection nerve block with ropivacaine.	7 days	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)
opioid consumption of 5-day continuous nerve block of the adductor canal relative to a single inection nerve block with ropivacaine.	7 days	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)

Secondary Outcome Measures

Name	Time	Method
physical and emotional functioning of 5-day continuous nerve blocks relative to a single injection nerve blocks with ropivacaine	7 days	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)
improvement in physical therapy milestones of 5-day continuous nerve blocks relative to a single injection nerve blocks with ropivacaine	30 days	Knee injury and osteoarthritis outcome score for joint replacement (KOOS JR)
30-day pain score measured in Numeric Rating Scale	30 days	At around 30 days postoperatively, the patients average pain score measured in the numeric rating scale (0-10) will be assessed.
30-day postoperative opioid consumption	30 days	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.