Authors: Kim et al.
Journal: BMJ Journals Regional Anesthesia & Pain Medicine
Published: June 2026
Summary:
This randomized controlled trial compared two approaches to adductor canal block for patients undergoing primary total knee arthroplasty. The study compared a single-injection adductor canal block with perineural dexamethasone against a continuous adductor canal catheter infusion.
The concern behind the study is that single-injection adductor canal blocks can wear off after the first 24 hours, potentially leading to rebound pain. Continuous catheters may extend the duration of analgesia, but they are more complex and may have catheter-related issues. The authors wanted to determine whether a continuous catheter would reduce opioid use during the 24- to 48-hour postoperative period.
The study included 94 patients undergoing primary unilateral total knee arthroplasty. The single-injection group received 15 mL of 0.25% bupivacaine with 2 mg perineural dexamethasone. The continuous catheter group received the same initial adductor canal block, followed by a catheter infusion of 0.2% ropivacaine at 8 mL/hour for 50 hours.
Both groups also received a comprehensive multimodal pain regimen, including an iPACK block, periarticular infiltration, oral pain medications, and telemedicine-based pain consultation.
The primary outcome was opioid consumption during the 24- to 48-hour postoperative period. There was no statistically significant difference between the continuous catheter group and the single-injection group. PACU opioid use also did not differ significantly between groups.
The continuous catheter group had catheter-associated buckling in 7% of patients, compared with 0% in the single-injection group. These events were transient. There were no significant differences in patient satisfaction, length of hospital stay, or functional recovery.
Why this matters:
This study suggests that, when a strong multimodal analgesic pathway is already being used, adding a continuous adductor canal catheter may not meaningfully reduce opioid use after total knee arthroplasty compared with a single-injection block using perineural dexamethasone.
Take-home point:
In patients undergoing total knee arthroplasty with multimodal analgesia, a continuous adductor canal catheter did not reduce opioid consumption compared with a single-injection adductor canal block with perineural dexamethasone.
Thank you to Regional Anesthesia & Pain Medicine for publishing this article and allowing us to summarize it.