title: Effect of adductor-canal-blockade on established, severe post-operative pain after total knee arthroplasty: a randomised study.
abstract: BACKGROUND
  In this proof-of-concept study, we investigated the effect of the predominantly sensory adductor-canal-blockade on established pain in the early post-operative period after total knee arthroplasty (TKA). We hypothesised that the adductor-canal-blockade would reduce pain during flexion of the knee (primary end point) and at rest, as well as reducing morphine consumption and morphine-related side effects (secondary outcomes) compared with placebo.
  
  
  METHODS
  We enrolled patients scheduled for elective TKA into this double-blind, placebo-controlled, randomised study. During general anaesthesia, we placed a catheter in the adductor canal, and after obtaining pre-block pain scores 30 min post-operatively, we injected 30 ml of ropivacaine 0.75% (n = 21) or saline (n = 20) according to randomisation. Clinicaltrials.gov Identifier: NCT01261897.
  
  
  RESULTS
  Forty-two patients were randomised, and 41 were analysed. Mean (standard deviation) pain scores during flexion of the knee at 1 h post-operatively were 58 (22) mm and 67 (29) mm, ropivacaine and placebo group, respectively (P = 0.23) but was significantly reduced in the ropivacaine group when calculated as area under the curve for the interval 1-6 h (P = 0.02). There were no statistically significant differences regarding pain at rest (P = 0.08), morphine consumption (P = 0.06), nor morphine-related side effects, apart from nausea (P = 0.04).
  
  
  CONCLUSIONS
  This proof-of-concept study shows promising results regarding the analgesic efficacy of adductor-canal-blockade in post-operative pain treatment after TKA, with a significant reduction in pain during flexion of the knee in the early post-operative period compared with placebo. However, the study was not sufficiently powered to permit final conclusions.
authors: Department of Anaesthesia, Copenhagen University Hospital, Gentofte, Denmark. pia.jaeger@rh.regionh.dk
authors: P
authors: P
authors: Jaeger
authors: U
authors: U
authors: Grevstad
authors: M H
authors: MH
authors: Henningsen
authors: B
authors: B
authors: Gottschau
authors: O
authors: O
authors: Mathiesen
authors: J B
authors: JB
authors: Dahl
mesh_terms: D000082:Acetaminophen / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016058:Analgesia, Patient-Controlled; D018712:Analgesics, Non-Narcotic / Q000627:therapeutic use; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D000768:Anesthesia, General; D019540:Area Under Curve; D019645:Arthroplasty, Replacement, Knee; D004311:Double-Blind Method; D023381:Endpoint Determination; D005260:Female; D006801:Humans; D007052:Ibuprofen / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009020:Morphine / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D009407:Nerve Block / Q000009:adverse effects*; D010147:Pain Measurement; D010149:Postoperative Pain / Q000188:drug therapy*; D020250:Postoperative Nausea and Vomiting / Q000453:epidemiology; D018401:Sample Size; D016896:Treatment Outcome
chemical_list: D018712:Analgesics, Non-Narcotic; D000701:Analgesics, Opioid; D000082:Acetaminophen; D009020:Morphine; D007052:Ibuprofen