title: Addition of morphine to intra-articular bupivacaine does not improve analgesia following knee joint replacement.
abstract: OBJECTIVE
  In an effort to further decrease postoperative opioid requirements and improve analgesia in patients undergoing elective knee joint replacement, a study was made of the effectiveness of adding morphine to an intra-articular bupivacaine injection given immediately following surgery.
  
  
  METHODS
  In random, double-blind fashion, 75 patients received a 31-mL intra-articular injection consisting of either 30 mL 0.5% bupivacaine with 1:200,000 epinephrine and 1 mL normal saline (group BUP), 30 mL 0.5% bupivacaine with 1:200,000 epinephrine and 1 mg (1 mL) preservative-free morphine (group BUP-MORPH), or 30 mL normal saline with 1:200,000 epinephrine and 1 mg preservative-free morphine (group MORPH). Postoperative analgesia was supplied by patient controlled analgesia (PCA) with morphine. Patients were assessed at 1, 2, 4, and 24 hours for pain (visual analog and verbal rating scales), morphine utilization, and side effects. Knee range of motion was measured before operation and at hospital discharge.
  
  
  RESULTS
  There was no difference among the three groups in PCA morphine requirements, pain scores by either scale, range of motion, or incidence of side effects, including somnolence, urinary retention, nausea and vomiting, and pruritus.
  
  
  CONCLUSIONS
  The addition of 1 mg morphine to an intra-articular injection of 30 mL 0.5% bupivacaine with 1:200,000 epinephrine given at wound closure does not improve analgesia in patients undergoing elective knee joint replacement.
authors.affiliation: Department of Anesthesiology, London Health Sciences Centre, University of Western Ontario, Canada.
authors.forename: N H
authors.initials: NH
authors.lastname: Badner
authors.forename: R B
authors.initials: RB
authors.lastname: Bourne
authors.forename: C H
authors.initials: CH
authors.lastname: Rorabeck
authors.forename: J A
authors.initials: JA
authors.lastname: Doyle
mesh_terms: D000328:Adult; D000368:Aged; D000701:Analgesics, Opioid / Q000008:administration & dosage*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D002045:Bupivacaine / Q000008:administration & dosage*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007270:Injections, Intra-Articular; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D009020:Morphine / Q000008:administration & dosage*; D010149:Postoperative Pain / Q000188:drug therapy*; D011446:Prospective Studies
chemical_list: D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D009020:Morphine; D002045:Bupivacaine