One hundred thirty-one patients with moderate knee osteoarthritis (OA) were randomized to receive bidirectional barbed polydioxanone filament (BBPF) insertion into the vastus medialis obliquus (VMO) (muscle enhancement and support therapy, MEST; n=88) or a sham needle procedure without filament insertion (n=43). The primary outcomes were pain on a 100-mm VAS during weight-bearing and walking. Secondary outcomes included isometric maximal contractile strength of the quadriceps (IMCSQ), Patient Global Impression of Change (PGIC), and Clinical Global Impression of Change (CGIC). Outcomes were assessed at baseline and at 4 and 8 weeks; an additional safety follow-up occurred at 24 weeks. Overall, the results revealed significantly greater pain reductions and strength gains in the MEST group at 4 and 8 weeks, alongside superior PGIC/CGIC ratings. These findings suggest BBPF-based VMO support may be a useful short-term adjunct for symptomatic knee OA.