Impact of Foot Posture Abnormalities on the Prevalence of Early Knee Osteoarthritis in Young Adults: A Cross-Sectional Study

Abstract

Background: Early-onset knee osteoarthritis (OA) is increasingly being reported among young adults, challenging the conventional view of OA as a disease of aging. Biomechanical factors, particularly foot posture abnormalities such as excessive pronation or supination, may contribute to altered lower limb mechanics, abnormal load distribution, and accelerated cartilage degeneration. Understanding the role of these modifiable risk factors in early disease development is essential for designing preventive strategies. Objective: To investigate the association between foot posture abnormalities and the prevalence of early knee osteoarthritis in young adults aged 18–40 years. Methods: A cross-sectional study was conducted on 180 participants recruited from physiotherapy and orthopedic clinics in Peshawar. Foot posture was assessed using the Foot Posture Index (FPI-6), and early knee OA was identified based on American College of Rheumatology (ACR) clinical criteria and Kellgren–Lawrence (K–L) grading (0–2). Pain intensity was measured using the Visual Analogue Scale (VAS), and function was evaluated with the Knee Injury and Osteoarthritis Outcome Score (KOOS). Statistical analyses included chi-square tests, t-tests, ANOVA, and logistic regression, with significance set at p < 0.05. Results: The mean age of participants was 29.4 ± 5.6 years, and the mean BMI was 26.1 ± 3.9 kg/m². Early knee OA was more prevalent among participants with pronated feet (50%) and supinated feet (39%) than those with neutral posture (22%) (p < 0.001). Individuals with pronated feet reported significantly higher pain scores (VAS: 5.1 ± 1.9) and poorer functional outcomes (KOOS: 68.4 ± 11.5) compared to those with neutral feet (VAS: 2.8 ± 1.4; KOOS: 82.6 ± 9.8). Logistic regression analysis identified abnormal foot posture (OR = 2.71, 95% CI: 1.45–5.06, p = 0.002) and elevated BMI (OR = 1.89, 95% CI: 1.02–3.52, p = 0.041) as independent predictors of early knee OA. Conclusion: Foot posture abnormalities — particularly excessive pronation — are significantly associated with early knee osteoarthritis in young adults. Along with elevated BMI, these findings underscore the importance of early screening for biomechanical risk factors and the implementation of targeted preventive interventions, including orthotic support, gait retraining, strengthening programs, and weight management, to reduce the long-term burden of OA