With the current trend toward ambulatory joint replacements, it is important to identify the approach to postoperative analgesia which best balances comfort and mobility. Adductor canal blocks provide analgesia after unicondylar knee replacement and can be performed with either an infusion catheter [adductor canal block catheter (ACB-C)] or as a single-shot injection [adductor canal block single-shot injection (ACB-SS)]. We conducted a retrospective analysis comparing the perceived quality of analgesia achieved by the 2 techniques, hypothesizing that patients receiving ACB-Cs would have less opioid consumption and lower pain scores than those who received ACB-SSs. After Institutional Review Board approval, we identified patients who underwent unicondylar knee arthroplasty between August and December 2015. Patients designated American Society of Anesthesiologists physical status 1 to 3 were included. Those discharged home on postoperative day (POD) 0 or provided an alternative nerve block were excluded. The primary outcome was opioid consumption over POD 1. Morning and afternoon pain scores were also evaluated. Of the 125 patients identified, there were 17 exclusions. Of those remaining, 69 received an ACB-C and 38 received an ACB-SS. The median amount of opioid use was lower in the ACB-C group than in the ACB-SS group [12 mg (8, 16) vs. 26 mg (20, 31.5), P<0.0001]. Patients treated with ACB-Cs had lower pain scores in the morning [0 (0, 1) vs. 3.5 (0, 5), P<0.0001] and afternoon [0 (0, 0) vs. 4 (0, 5), P<0.0001] on POD 1. Our data suggest an association between adductor canal catheters and both lower opioid consumption and pain scores. A prospective randomized trial is required to confirm this finding and help determine the optimal intervention.
Icahn School of Medicine at Mount Sinai, Mount Sinai St. Luke’s and West Hospitals, New York, NY
The authors declare that they have nothing to disclose.
For reprint requests, or additional information and guidance on the techniques described in the article, please contact Jonathan A. Paul, DO, at or by mail at Department of Anesthesiology, Icahn School of Medicine at Mount Sinai, Mount Sinai St. Luke’s and West Hospitals, Suite 5C-03, 1000 10th Avenue, New York, NY 10019. You may inquire whether the author(s) will agree to phone conferences and/or visits regarding these techniques.