Effect of eccentric exercise combined with multimodal intervention on knee pain, physical function, and psychological outcome in people with knee osteoarthritis: A randomized controlled trial

Background Knee osteoarthritis (KOA) is a leading cause of pain and impaired quality of life. Although multimodal rehabilitation is recommended, additional benefit of eccentric strengthening within such programs remains unclear. Objective To evaluate whether adding eccentric exercise to multimodal intervention improves pain, physical function, and psychological outcome in KOA. Methods This trial included 120 KOA participants, randomly allocated to experimental group (eccentric exercise plus multimodal intervention; n = 60) or control group (multimodal intervention alone; n = 60). Both groups received supervised treatment for 6 weeks. Outcomes were assessed at baseline, post-intervention (week-6), and follow-up (week-30). Domains included pain (Numeric Pain Rating Scale [NPRS] and pressure pain threshold [PPT]), physical function (muscle strength, Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC], range of motion [ROM], and Six-Minute Walk Test [6MWT]), and psychological status (Patient Health Questionnaire-9 [PHQ-9]). Results Both groups improved over time, with greater improvements in the experimental group. At week 6, between-group differences favored the experimental group for NPRS (MD −0.570, 95% CI −1.003 to −0.136), PPT (0.225 kg/cm 2 , 0.131 to 0.319), WOMAC pain (−1.145, −1.929 to −0.361), function (−2.646, −4.708 to −0.584), 6MWT (19.347 m, 14.743 to 23.951), and PHQ-9 (−1.136, −1.877 to −0.394). At week 30, these benefits were sustained or increased, with additional improvement in knee-flexion ROM (3.139°, 1.128 to 5.150); although knee-extension ROM did not differ. No serious adverse events occurred. Conclusion Integrating eccentric strengthening into multimodal rehabilitation yields superior, sustained improvements in pain, physical function, and psychological outcome in KOA.