title: Small-dose ketamine infusion improves postoperative analgesia and rehabilitation after total knee arthroplasty.
abstract: We designed this study to evaluate the effect of small-dose IV ketamine in combination with continuous femoral nerve block on postoperative pain and rehabilitation after total knee arthroplasty. Continuous femoral nerve block was started with 0.3 mL/kg of 0.75% ropivacaine before surgery and continued in the surgical ward for 48 h with 0.2% ropivacaine at a rate of 0.1 mL . kg(-1) . h(-1). Patients were randomly assigned to receive an initial bolus of 0.5 mg/kg ketamine followed by a continuous infusion of 3 mug . kg(-1) . min(-1) during surgery and 1.5 mug . kg(-1) . min(-1) for 48 h (ketamine group) or an equal volume of saline (control group). Additional postoperative analgesia was provided by patient-controlled IV morphine. Pain scores and morphine consumption were recorded over 48 h. The maximal degree of active knee flexion tolerated was recorded daily until hospital discharge. Follow-up was performed 6 wk and 3 mo after surgery. The ketamine group required significantly less morphine than the control group (45 +/- 20 mg versus 69 +/- 30 mg; P < 0.02). Patients in the ketamine group reached 90 degrees of active knee flexion more rapidly than those in the control group (at 7 [5-11] versus 12 [8-45] days, median [25%-75% interquartile range]; P < 0.03). Outcomes at 6 wk and 3 mo were similar in each group. These results confirm that ketamine is a useful analgesic adjuvant in perioperative multimodal analgesia with a positive impact on early knee mobilization. No patient in either group reported sedation, hallucinations, nightmares, or diplopia, and no differences were noted in the incidence of nausea and vomiting between the two groups.
authors.affiliation: Departments of Anesthesia and INSERM E 332, Hôpital Ambroise Pare, Assistance Publique-Hôpitaux de Paris, 92100 Boulogne, France; Hôpital Raymond Poincaré, Assistance Publique Hôpitaux de Paris, 92428 Garches, France; and the Outcomes Research™ Institute and Departments of Anesthesiology and Pharmacology, University of Louisville, Louisville, Kentucky.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Adam
authors.forename: Marcel
authors.initials: M
authors.lastname: Chauvin
authors.forename: Bertrand
authors.initials: B
authors.lastname: Du Manoir
authors.forename: Mathieu
authors.initials: M
authors.lastname: Langlois
authors.forename: Daniel I
authors.initials: DI
authors.lastname: Sessler
authors.forename: Dominique
authors.initials: D
authors.lastname: Fletcher
mesh_terms: D000368:Aged; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000627:therapeutic use; D000778:Anesthetics, Dissociative / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D019645:Arthroplasty, Replacement, Knee; D004311:Double-Blind Method; D018691:Excitatory Amino Acid Antagonists / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D005267:Femoral Nerve; D006801:Humans; D007649:Ketamine / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D007717:Knee / Q000502:physiology; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000627:therapeutic use; D009407:Nerve Block; D010147:Pain Measurement; D010149:Postoperative Pain / Q000188:drug therapy*; D011182:Postoperative Care; D020250:Postoperative Nausea and Vomiting / Q000453:epidemiology; D012046:Rehabilitation
chemical_list: D000701:Analgesics, Opioid; D000778:Anesthetics, Dissociative; D018691:Excitatory Amino Acid Antagonists; D007649:Ketamine; D009020:Morphine