One hundred and twelve patients undergoing total knee arthroplasty were randomized to receive either ATX101 (1000 mg, n=37 or 1500 mg, n=37) or a control treatment (bupivacaine, n=34 or placebo, n=4). The primary outcome of interest was the area under the curve (AUC) of pain intensity measured by the Numerical Rating Scale for Resting Pain (NRS-R) from 30 minutes to 8 days. Secondary outcomes included opioid consumption, functional measures, and adverse events. The results showed that ATX101 significantly reduced opioid consumption by 23% and improved function, with the 1500 mg cohort achieving better range of motion and walking/standing performance. ATX101 also demonstrated reduced opioid use, improved pain control after the first 24 hours, and fewer adverse effects like nausea and constipation. Overall, ATX101 provided a promising alternative to standard opioid management following total knee arthroplasty.