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The Analgesic Effect of Obturator Nerve Block Added to a Femoral Triangle Block After Total Knee Arthroplasty: A Randomized Controlled Trial
  1. Charlotte Runge, MD*,
  2. Jens Børglum, MD, PhD,
  3. Jan Mick Jensen, MD,
  4. Tina Kobborg, MD*,
  5. Anette Pedersen, MD*,
  6. Jon Sandberg, MD*,
  7. Lone Ramer Mikkelsen, PhD*,
  8. Morten Vase, MD* and
  9. Thomas Fichtner Bendtsen, MD, PhD
  1. From the *Elective Surgery Centre, Silkeborg Regional Hospital, Silkeborg; †Department of Anesthesiology, Zealand University Hospital, Roskilde; and ‡Department of Anesthesiology, Aarhus University Hospital, Aarhus, Denmark
  1. Address correspondence to: Thomas Fichtner Bendtsen, MD, PhD, Department of Anesthesiology, Aarhus University Hospital, Noerrebrogade 44, DK-8000 Aarhus, Denmark (e-mail: tfb{at}


Background and Objectives Total knee arthroplasty (TKA) is associated with severe pain, and effective analgesia is essential for the quality of postoperative care and ambulation. The analgesic effects of adding an obturator nerve block (ONB) to a femoral triangle block (FTB) after TKA have not been tested previously. We hypothesized that combined ONB and FTB will reduce opioid consumption and pain compared with those of a single FTB or local infiltration analgesia (LIA).

Methods Seventy-eight patients were randomized to combined ONB and FTB, single FTB, or LIA after primary unilateral TKA. The primary outcome was morphine consumption during the first 24 postoperative hours. Secondary outcomes included morphine consumption during the first 48 postoperative hours, pain at rest and passive knee flexion, nausea and vomiting, cumulated ambulation score, and Timed Up and Go test.

Results Seventy-five patients were included in the analysis. The total intravenous morphine consumption during the first 24 postoperative hours was 2 mg (interquartile range [IQR], 0–15) in the combined ONB and FTB group, 20 mg (IQR, 10–26) in the FTB group (P = 0.0007), and 17 mg (IQR, 10–36) in the LIA group (P = 0.002). The combined ONB and FTB group displayed reduced pain, nausea, and vomiting compared with the other groups. The ambulation tests showed no statistically significant differences between the groups.

Conclusions Addition of ONB to FTB significantly reduced opioid consumption and pain after TKA compared with a single FTB or LIA, without impaired ambulation.

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  • The authors declare no conflict of interest.

    The study was supported by the A.P. Møller and Chastine Mc-Kinney Møller Foundation.