Newly Published
Pain Medicine  |   June 2019
Opioid- and Motor-sparing with Proximal, Mid-, and Distal Locations for Adductor Canal Block in Anterior Cruciate Ligament Reconstruction: A Randomized Clinical Trial
Author Notes
  • From the Department of Anesthesiology and Pain Medicine, and the Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada (F.W.A.); the Department of Anesthesia (F.W.A.), the Li Ka Shing Knowledge Institute (F.W.A.), the Department of Anesthesia (J.M., G.A.P., R.M., R.B.) and the Department of Surgery, Division of Orthopedic Surgery, Women’s College Hospital (J.C., J.T., T.D.), the Department of Anesthesia, Toronto Western Hospital (G.A.P.), University of Toronto, Toronto, Ontario, Canada.
  • Submitted for publication December 7, 2018. Accepted for publication April 25, 2019.
    Submitted for publication December 7, 2018. Accepted for publication April 25, 2019.×
  • Correspondence: Address correspondence to Dr. Brull: Women’s College Hospital, Toronto, Ontario M5S 1B2, Canada. richard.brull@wchospital.ca. Information on purchasing reprints may be found at www.anesthesiology.org or on the masthead page at the beginning of this issue. Anesthesiology’s articles are made freely accessible to all readers, for personal use only, 6 months from the cover date of the issue.
Article Information
Pain Medicine / Pain Medicine / Pharmacology / Opioid
Pain Medicine   |   June 2019
Opioid- and Motor-sparing with Proximal, Mid-, and Distal Locations for Adductor Canal Block in Anterior Cruciate Ligament Reconstruction: A Randomized Clinical Trial
Anesthesiology Newly Published on June 19, 2019. doi:10.1097/ALN.0000000000002817
Anesthesiology Newly Published on June 19, 2019. doi:10.1097/ALN.0000000000002817
Abstract

Editor’s Perspective:

What We Already Know about This Topic:

  • Adductor canal nerve block is useful for a range of knee surgeries, although the optimal injection location has not been defined

  • Unfortunately, analgesia achieved using adductor canal block is sometimes accompanied by unwanted motor block

What This Article Tells Us That Is New:

  • Proximal adductor canal injections were associated with lower first 24-h morphine consumption than when injections were more distal

  • Decreases in quadriceps strength were similar whether the injection was made in a proximal, mid-, or distal adductor canal location

Background: The ideal location for single-injection adductor canal block that maximizes analgesia while minimizing quadriceps weakness after painful knee surgery is unclear. This triple-blind trial compares ultrasound-guided adductor canal block injection locations with the femoral artery positioned medial (proximal adductor canal), inferior (mid-adductor canal), and lateral (distal adductor canal) to the sartorius muscle to determine the location that optimizes postoperative analgesia and motor function. The hypothesis was that distal adductor block has (1) a superior opioid-sparing effect and (2) preserved quadriceps strength, compared with proximal and mid-locations for anterior cruciate ligament reconstruction.

Methods: For the study, 108 patients were randomized to proximal, mid-, or distal adductor canal injection locations for adductor canal block. Cumulative 24-h oral morphine equivalent consumption and percentage quadriceps strength decrease (maximum voluntary isometric contraction) at 30 min postinjection were coprimary outcomes. The time to first analgesic request, pain scores, postoperative nausea/vomiting at least once within the first 24 h, and block-related complications at 2 weeks were also evaluated.

Results: All patients completed the study. Contrary to the hypothesis, proximal adductor canal block decreased 24-h morphine consumption to a mean ± SD of 34.3 ± 19.1 mg, (P < 0.0001) compared to 64.0 ± 33.6 and 65.7 ± 22.9 mg for the mid- and distal locations, respectively, with differences [95% CI] of 29.7 mg [17.2, 42.2] and 31.4 mg [21.5, 41.3], respectively, mostly in the postanesthesia care unit. Quadriceps strength was similar, with 16.7%:13.4%:15.3% decreases for proximal:mid:distal adductor canal blocks. The nausea/vomiting risk was also lower with proximal adductor canal block (10 of 34, 29.4%) compared to distal location (23 of 36, 63.9%; P = 0.005). The time to first analgesic request was longer, and postoperative pain was improved up to 6 h for proximal adductor canal block, compared to mid- and distal locations.

Conclusions: : A proximal adductor canal injection location decreases opioid consumption and opioid-related side effects without compromising quadriceps strength compared to mid- and distal locations for adductor canal block in patients undergoing anterior cruciate ligament reconstruction.