Postoperative duloxetine administration did not significantly modify overall pain trajectories following high tibial osteotomy: An open-label randomized controlled trial

BackgroundDuloxetine is a potent analgesic that reduces pain associated with knee osteoarthritis. This study aimed to evaluate the analgesic effects of regular postoperative duloxetine after high tibial osteotomy (HTO) and its influence on knee function, pain severity, and daily life.MethodsThis open-label randomised controlled trial was designed as a single-centre, parallel-group study. Patients undergoing HTO were randomly allocated to the control and duloxetine groups. Patients allocated to the duloxetine group were administered oral duloxetine for the first 12 weeks postoperatively and were followed up for 6 months following surgery. The primary outcome was pain assessed by the visual analogue scale (VAS), and secondary outcomes included evaluations using the Brief Pain Inventory, the Knee Society Score, and the 2011 Knee Society Score.ResultsA total of 38 patients in the duloxetine group and 37 patients in the control group were analyzed. The duloxetine group demonstrated significantly lower pain VAS scores at rest 6 months postoperatively compared with the control group (0.5 ± 1.0 vs 1.3 ± 2.0, respectively; <i>p</i> = 0.029). There were no significant differences between the groups in the other scores. However, patients in the duloxetine group showed significantly lower consumption of acetaminophen in the third postoperative week (0.0 ± 0.0 vs 0.3 ± 0.8 tablets/day, respectively).ConclusionsDuloxetine demonstrated a modest analgesic benefit following HTO, with reduced pain at rest at 6 months and decreased rescue medication use during the third postoperative week. Routine use after HTO may therefore not be warranted in unselected patients. Due to the open-label design, performance and detection bias cannot be excluded.Trial registrationThe study protocol was registered in the UMIN clinical trial registration before starting recruitments: UMIN000040026 (registration date: June 1, 2020) https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000045630.