One hundred patients with knee osteoarthritis undergoing primary total knee arthroplasty were randomized to receive either oral nefopam (40 mg twice daily) alongside celecoxib and pregabalin (n=50) or a placebo alongside the same regimen (n=50). The primary outcome was postoperative consumption of rescue analgesics (oxycodone and morphine). Secondary outcomes included pain scores (VAS) at rest and during motion, knee functional recovery (range of motion and ambulation distance), length of hospital stay, liver function indicators, and complication rates. Outcomes were assessed during hospitalization and within the first 48 hours postoperatively. Overall, the nefopam group showed statistically significant reductions in opioid consumption and pain scores, along with better functional recovery and shorter hospital stays. However, the magnitude of these improvements was not deemed clinically significant. These findings suggest that oral nefopam could provide modest benefits as part of multimodal analgesia for TKA.