Brief communication (Original). Preoperative pregabalin and/or celecoxib for pain management after total knee arthroplasty under intrathecal morphine: a randomized controlled trial

Background: Although spinal anesthesia with intrathecal morphine is considered to be an alternative technique for analgesia after total knee arthroplasty (TKA), it is simple, easy to perform, and economical. Information to improve postoperative outcome of intrathecal morphine for TKA is still limited. Objective: To investigate whether preoperative combination of pregabalin and celecoxib is superior to either drug alone to improve the analgesic efficacy of intrathecal morphine for patients after TKA. Methods: A randomized, placebo-controlled, double-blind trial of pregabalin (150 mg), celecoxib (400 mg), or in combination, administered before TKA. All patients received spinal anesthesia with intrathecal morphine 0.2 mg and patient-controlled analgesic morphine postoperatively. The primary outcome was 24 hours cumulative morphine consumption. Secondary outcomes included time to first dose of morphine, 0-10 Visual Analog Scale (VAS) of pain scores at rest and when moving, VAS anxiety scores, patient satisfaction 0-10 score, postoperative adverse effects, and complications. Results: One hundred patients were randomly assigned into four groups. There were no differences in the 24-h cumulative morphine consumption, time to first dose of morphine and in the results of the 24 hours of VAS pain scores at rest. Compared with the placebo group, pain scores when moving at 2 hours in the pregabalin-celecoxib group was significantly lower (p < 0.05). Significant decrease of anxiety scores were shown in the pregabalincelecoxib group at 2 hours and together with the celecoxib group at 6 hours and 24 hours postoperatively (p < 0.05). Postoperative adverse effects and complications were similar in all groups except for transcutaneous oxygen saturation (SpO ) < 92% in the pregabalin group at the end of surgery. The patient satisfaction at 24 and 48 hours after surgery was similar in all groups. Conclusion: Preoperative pregabalin, celecoxib alone, or as a combination does not improve the analgesic effect of 0.2 mg intrathecal morphine for patients after TKA. Although preoperative pregabalin with celecoxib may statistically decrease patients’ anxiety score for 24 hours postoperatively with comparable adverse effects, no clinical significance is observed