Cross-Cultural Adaptation and Validation for Central Aspects of Pain in the Knee Questionnaire: Based on Chinese Patients Undergoing Total Knee Arthroplasty for Knee Osteoarthritis

Background: This study aimed to develop a simplified Chinese version of the Central Aspects of Pain in the Knee (CAP-Knee-CV) questionnaire and to evaluate its psychometric properties in patients with knee osteoarthritis (KOA). Methods: The CAP-Knee-CV was developed using a standardized forward-backward translation procedure, followed by expert panel review to ensure cultural and linguistic equivalence. A total of 120 patients with KOA scheduled for total knee arthroplasty (TKA) were recruited from a tertiary orthopedic center in Xi'an, China. Among them, 50 participants were randomly selected to complete the questionnaire again after one week. Reliability and validity were assessed through exploratory factor analysis, internal consistency, test-retest reliability, and correlation analyses with established clinical measures. Results: The CAP-Knee-CV consisted of 8 items loading on two factors, accounting for 66.1% of the total variance. Internal consistency was good (Cronbach's α = 0.843), and test-retest reliability was excellent (intraclass correlation coefficient = 0.957). The CAP-Knee-CV showed significant correlations with the Central Sensitization Inventory (r = 0.610), pain intensity while walking (r = 0.697), the Western Ontario and McMaster Universities Osteoarthritis Index (r = 0.530), and the 5-level EQ-5D (r = 0.510). Conclusion: The CAP-Knee-CV was successfully translated and cross-culturally adapted into simplified Chinese. It demonstrated satisfactory reliability, validity, and feasibility, making it a promising tool for assessing central sensitization in Chinese-speaking patients with KOA undergoing TKA.