Intravenous Parecoxib and Continuous Femoral Block for Postoperative Analgesia after Total Knee Arthroplasty. A Randomized, DoubleBlind, Prospective Trial

Abstract

Background: Up until now, the optimal strategy for postoperative pain management after total knee arthroplasty (TKA) remains to be elucidated. Objective: The current investigation aimed to examine the analgesic efficacy and the opioid sparing effects of intravenous parecoxib in combination with continuous femoral blockade. Study Design: Randomized, double-blind, prospective trial. Setting: University hospital in the United Kingdom. Methods: In total, 90 patients underwent TKA under subarachnoid anesthesia and received continuous femoral block initially as a bolus with 20 mL of ropivacaine 0.75%. Infusion of 0.2% on 10 mL/h followed. Patients were randomized into 2 groups. Group D and Group P received parecoxib and placebo, respectively at 12 hour time intervals. Visual analog scale (VAS) pain scores were obtained at different time intervals including 4, 8, 12, 24 and 36 hours. The pain scores were measured with patients in a resting position. Morphine could also be administered with a patient controlled analgesia (PCA) pump if the specified analgesia was deemed inadequate (VAS > 5). Results: None of the patients were withdrawn from the study. Parecoxib provided greater relief than placebo following TKA. The VAS pain scores measured at rest were statistically significantly lower in parecoxib-treated patients compared to the placebo group (P = 0.007) at 4 (P = 0.044), 12 (P = 0.001), and 24 hours (P = 0.012), postoperatively. Patients receiving parecoxib consumed less morphine at all time intervals than patients receiving placebo, with borderline statistical significance (P = 0.054). In each time period, all patients receiving continuous femoral block irrespectively of the treatment group, required low morphine doses. Limitations: Current protocol did not answer question as to functional recovery. Conclusion: According to our findings intravenous parecoxib in combination with continuous femoral block provided superior analgesic efficacy and opioid sparing effects in patients undergoing TKA. Key words: Anesthesia, TKA, morphine, opioids, VAS scores, continuous femoral block