<b>Correlation Between Quadriceps Muscles Strength and Functional Disability in Patients with Knee Osteoarthritis</b>

Background: Knee osteoarthritis is a common chronic musculoskeletal disorder associated with pain, stiffness, quadriceps weakness, mobility limitation, and reduced functional performance. Quadriceps muscle strength is clinically important for knee stability and activities of daily living, but local evidence regarding its association with functional disability remains limited. Objective: To determine the correlation between bilateral quadriceps muscle strength and functional disability among patients with knee osteoarthritis. Methods: A cross-sectional observational study was conducted among 60 patients with knee osteoarthritis recruited through convenience sampling. Pain intensity was assessed using the Visual Analogue Scale, functional disability was measured using the Western Ontario and McMaster Universities Osteoarthritis Index, and quadriceps muscle strength was assessed through Manual Muscle Testing. Data were analyzed using SPSS version 25. Normality was assessed using Kolmogorov-Smirnov and Shapiro-Wilk tests, and Spearman’s rank-order correlation was used because key variables were not normally distributed. Results: The mean age of participants was 52.90 ± 4.77 years, and the mean body mass index was 29.76 ± 3.60 kg/m². Mean pain during walking was higher than pain at rest. Bilateral quadriceps strength showed strong negative correlations with WOMAC pain (rho = -0.950), WOMAC stiffness (rho = -0.904), WOMAC function (rho = -0.946), and total WOMAC score (rho = -0.946), all with p < 0.001. Conclusion: Lower quadriceps muscle strength was strongly associated with greater pain, stiffness, and functional disability in patients with knee osteoarthritis. Quadriceps strength assessment should be considered an important component of clinical evaluation and rehabilitation planning.