Résumé : Purpose: Effectiveness of sufentanil sublingual tablet system (SSTS) compared to oral oxycodone in the management of postoperative pain after total knee arthroplasty (TKA) within an enhanced recovery after surgery (ERAS) protocol. Methods: This pragmatic, parallel, open label, randomized controlled, trial enrolled 72 adult patients scheduled for TKA under spinal anesthesia following ERAS pathway. In addition to multimodal analgesia, patients received SSTS 15 mcg (SSTS group) or oral oxycodone extended release 10 mg twice daily and oral oxycodone immediate-release 5 mg up to four times daily on demand (Oxy group) to control pain during 48 h postoperatively. The primary endpoint was pain measured using a numeric rating scale at 24 h postoperatively. Time to first mobilization, side effects and patient satisfaction were also recorded. Results: Median pain score at 24 h at rest was 3 [2–4] for Oxy group vs 2 [1.75–3] for SSTS group (p = 0.272) whereas median pain score on movement was 4 [3–6] vs 3 [2–5] respectively (p = 0.059). No difference in time to first mobilization was found between the two groups. The method of pain control was judged good/excellent for 83.9% of patients in the SSTS group compared with 52.9% in the Oxy group (p = 0.007). The incidence of nausea was 33% in SSTS group and 9% in Oxy group (p = 0.181). Conclusions: In complement to ERAS multimodal analgesia, sublingual sufentanil 15 mcg tablet system did not show clinically significant pain improvement compared to oral oxycodone after total knee arthroplasty. Trial registration: Clinical Trials: NCT04448457; retrospectively registered on June 24, 2020. https://clinicaltrials.gov/ct2/show/NCT04448457?cond=sublingual+sufentanil&cntry=BE&draw=2&rank=3.