Effect of Quadriceps Isometric Set on Pain Reduction in Unilateral Knee Osteoarthritis Patients

Abstract

Background: Osteoarthritis is a chronic joint disorder caused by cartilage damage, and its prevalence increases significantly with age. Knee osteoarthritis often results in pain, stiffness, swelling, and limited joint motion that restrict daily activities. The American College of Rheumatology recommends non-pharmacological management, particularly exercise therapy and psychosocial interventions. Physiotherapy has a key role in pain reduction, one of which is through the Quadriceps Isometric Set exercise, a static muscle contraction without changes in muscle length or joint movement. Objectives: This study aimed to determine the between-group difference (ΔVAS ± 95% CI) in pain reduction following a QIS exercise program in patients with unilateral knee osteoarthritis. Methods: A quasi-experimental nonequivalent-control-group design was used. Thirty-two participants aged 40–75 years were divided into an intervention group (QIS exercise) and a control group (no intervention). Pain was measured using the 0–10 Visual Analogue Scale (VAS) before and after six sessions over two weeks. Data were analyzed using paired and independent t-tests. Results: The mean VAS in the intervention group decreased from 6.99 ± 1.67 to 4.00 ± 1.55, while the control group showed no change (4.86 ± 1.39 to 4.86 ± 1.39). The between-group mean difference (ΔVAS) was 2.98 (95% CI 2.2–3.7, p = 0.001). Conclusion: The Quadriceps Isometric Set exercise significantly reduced pain in unilateral knee-OA patients compared with controls.