Abstract / Summary
Transdermal nonsteroidal anti-inflammatory drugs (NSAIDs) are increasingly used for knee osteoarthritis (OA), but evidence in patients with moderate to severe disease remains limited. This study aimed to evaluate the efficacy and short-term safety of S-flurbiprofen plaster compared with placebo in patients with moderate to severe knee OA. In this randomized, double-blind, placebo-controlled trial, patients with Kellgren-Lawrence grade III–IV knee OA were assigned (1:1) to receive S-flurbiprofen plaster (40 mg) or placebo once daily for 2 weeks. The primary outcome was change in pain severity measured by the Visual Analog Scale (VAS). Secondary outcomes included the Knee injury and Osteoarthritis Outcome Score (KOOS), rescue medication use, and adverse events. Assessments were conducted at baseline, 1, 2, and 4 weeks. Of the 58 patients included in the analysis, 29 were assigned to each group. Baseline demographic and clinical characteristics were comparable between the two groups. For VAS, a significant group-by-time interaction was observed ( p = 0.028). However, no statistically significant between-group differences were observed at any individual follow-up time point. For KOOS, neither the group-by-time interaction nor the between-group differences at individual follow-up time points were statistically significant. Rescue medication use was comparable between groups, and no serious gastrointestinal or cardiovascular adverse events occurred. S-flurbiprofen plaster did not demonstrate statistically significant superiority over placebo for pain or knee function during the treatment period. Further studies are warranted to clarify long-term effectiveness and safety. Thai Clinical Trials Registry, TCTR20241110007, registered on 10 Nov 2024. (https//www.thaiclinicaltrials.org/)