title: Adductor canal block versus femoral nerve block for total knee arthroplasty: a prospective, randomized, controlled trial.
abstract: BACKGROUND
  This prospective double-blinded, randomized controlled trial compared adductor canal block (ACB) with femoral nerve block (FNB) in patients undergoing total knee arthroplasty. The authors hypothesized that ACB, compared with FNB, would exhibit less quadriceps weakness and demonstrate noninferior pain score and opioid consumption at 6 to 8 h postanesthesia.
  
  
  METHODS
  Patients received an ACB or FNB as a component of a multimodal analgesic. Quadriceps strength, pain score, and opioid consumption were assessed on both legs preoperatively and at 6 to 8, 24, and 48 h postanesthesia administration. In a joint hypothesis test, noninferiority was first evaluated on the primary outcomes of strength, pain score, and opioid consumption at 6 to 8 h; superiority on each outcome at 6 to 8 h was then assessed only if noninferiority was established.
  
  
  RESULTS
  Forty-six patients received ACB; 47 patients received FNB. At 6 to 8 h postanesthesia, ACB patients had significantly higher median dynamometer readings versus FNB patients (median [interquartile range], 6.1 kgf [3.5, 10.9] (ACB) vs. 0 kgf [0.0, 3.9] (FNB); P < 0.0001), but was not inferior to FNB with regard to Numeric Rating Scale pain scores (1.0 [0.0, 3.5] ACB vs. 0.0 [0.0, 1.0] FNB; P = 0.019), or to opioid consumption (32.2 [22.4, 47.5] ACB vs. 26.6 [19.6, 49.0]; P = 0.0115). At 24 and 48 h postanesthesia, there was no significant statistical difference in dynamometer results, pain scores, or opioid use between the two groups.
  
  
  CONCLUSIONS
  At 6 to 8 h postanesthesia, the ACB, compared with the FNB, exhibited early relative sparing of quadriceps strength and was not inferior in both providing analgesia or opioid intake.
authors.affiliation: From the Department of Anesthesiology, Hospital for Special Surgery, New York, New York (D.H.K., Y.L., E.A.G., R.L.K., D.B.M., A.K.G., and J.T.Y.); Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University, Baltimore, Maryland (A.M.); Department of Anesthesiology, Weill-Cornell Medical Center, New York, New York (M.L.P.); and Department of Epidemiology and Biostatistics Core, Hospital for Special Surgery, New York, New York (Y.-y.L. and Y.M.).
authors.forename: David H
authors.initials: DH
authors.lastname: Kim
authors.forename: Yi
authors.initials: Y
authors.lastname: Lin
authors.forename: Enrique A
authors.initials: EA
authors.lastname: Goytizolo
authors.forename: Richard L
authors.initials: RL
authors.lastname: Kahn
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Maalouf
authors.forename: Asha
authors.initials: A
authors.lastname: Manohar
authors.forename: Minda L
authors.initials: ML
authors.lastname: Patt
authors.forename: Amanda K
authors.initials: AK
authors.lastname: Goon
authors.forename: Yuo-Yu
authors.initials: YY
authors.lastname: Lee
authors.forename: Yan
authors.initials: Y
authors.lastname: Ma
authors.forename: Jacques T
authors.initials: JT
authors.lastname: Yadeau
mesh_terms: D000368:Aged; D016058:Analgesia, Patient-Controlled / Q000379:methods; D000701:Analgesics, Opioid / Q000627:therapeutic use; D000779:Anesthetics, Local / Q000008:administration & dosage*; D019645:Arthroplasty, Replacement, Knee; D002045:Bupivacaine / Q000008:administration & dosage; D004311:Double-Blind Method; D005260:Female; D005267:Femoral Nerve / Q000187:drug effects*; D006801:Humans; D004091:Hydromorphone / Q000627:therapeutic use; D008297:Male; D018908:Muscle Weakness / Q000139:chemically induced; D009407:Nerve Block / Q000379:methods*; D010098:Oxycodone / Q000627:therapeutic use; D010147:Pain Measurement / Q000379:methods; D010149:Postoperative Pain / Q000188:drug therapy*; D011183:Postoperative Complications / Q000139:chemically induced*; D011446:Prospective Studies; D052097:Quadriceps Muscle / Q000187:drug effects; D016896:Treatment Outcome
chemical_list: D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D010098:Oxycodone; D004091:Hydromorphone; D002045:Bupivacaine