Reliability and validity of the Persian knee Self-Efficacy Scale in patients with knee injuries: a cross-sectional validation study.

Abstract

The Knee Self-Efficacy Scale (K-SES) is widely used to assess patients' confidence after knee injury, but no validated Persian version exists, limiting its use in Persian-speaking populations. This study aimed to translate, adapt, and evaluate the psychometric properties of the Persian-language versions of the K-SES (K-SES-Persian). One hundred and six Persian patients with knee injuries were recruited from orthopedic and physiotherapy centers. Construct validity was examined using confirmatory factor analysis and Pearson correlations. Reliability was assessed by Cronbach's alpha and intraclass correlation coefficients (ICC). Convergent validity was tested with the Oxford Knee Score (OKS) and Knee outcome survey activities for daily living (KOS-ADL). Test-retest reliability was assessed in 53 patients after 7-8 days. The K-SES-Persian showed excellent internal consistency for total score (α = 0.965). An excellent internal consistency (α = 0.953) was shown for present score and good internal consistency (α = 0.898) for the future score. The factor loading for each item was greater than 0.70. The K-SES-Persian showed significant correlations with the OKS (r = 0.37, 95% CI: 0.19-0.53, p < 0.001) and the KOS-ADL (r = 0.33, 95% CI: 0.15-0.49, p = 0.001). A significant but weak correlation was found between the OKS and KOS-ADL (r = 0.219 p = 0.024), indicating limited consistency between the comparator measures used for evaluating the convergent validity of the K-SES-Persian. No floor or ceiling effects were observed. The K-SES-Persian was successfully adapted and demonstrated sound psychometric properties, including construct validity, internal consistency, and test-retest reliability, with internal consistency varying across subscales, supporting its use among Persian-speaking patients with knee injuries.