Associations of rumination and worry with pain and functional limitation in knee osteoarthritis

Pain and functional limitation in knee osteoarthritis are not always proportional to radiographic severity. This cross-sectional study examined whether worry and rumination were associated with pain and functional impairment after accounting for Kellgren–Lawrence (K–L) severity. We included 156 consecutive patients with K–L grade 1 to 4 knee osteoarthritis recruited from an orthopedics outpatient clinic between February and April 2026. In bilateral cases, the predominantly symptomatic knee was used for K–L grading and scale-based symptom assessment. Pain intensity was assessed with the Visual Analog Scale (VAS), and symptom burden and functional limitation were evaluated using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Worry and rumination were measured with the Penn State Worry Questionnaire and Ruminative Thought Style Questionnaire, respectively. Associations were examined using Spearman correlations and multivariable linear regression for total WOMAC and VAS scores, adjusted for age, sex, body mass index, K–L grade, worry, and rumination. VAS, WOMAC stiffness, physical function, and total scores differed significantly across K–L grades, whereas WOMAC pain did not; worry and rumination did not differ across radiographic severity groups. After false discovery rate correction, rumination showed the strongest correlations with WOMAC and VAS outcomes. In multivariable analyses, K–L grade and rumination were independently associated with total WOMAC (adjusted R 2 = 0.379; K–L: B = 7.066, β = 0.374, 95% confidence interval [CI]: 4.164–9.969, P < .001; rumination: B = 0.372, β = 0.566, 95% CI: 0.255–0.489, P < .001) and VAS (adjusted R 2 = 0.220; K–L: B = 0.793, β = 0.354, 95% CI: 0.407–1.179, P < .001; rumination: B = 0.036, β = 0.463, 95% CI: 0.021–0.052, P < .001). In patients with knee osteoarthritis, symptom severity appears to reflect both structural disease burden and cognitive-emotional factors. Rumination was independently associated with pain and functional limitation beyond radiographic severity, supporting a biopsychosocial approach to clinical assessment.