Psychometric properties of the German Self-efficacy Expectation Scale (SES-G) in patients undergoing primary total...

To translate and culturally adapt the Self-efficacy Expectation Scale (SES) into German and examine its psychometric properties for total hip arthroplasty (THA) patients.

The English-language SES was translated into German (SES-G). 116 patients completed the SES-G together with the Self-Efficacy for Rehabilitation Outcome Scale-German version (SER-G), Hip Disability and Osteoarthritis Outcome Scale (HOOS), and Hospital for Special Surgery Hip Expectation Survey (HSS-HRES). Structural validity was assessed using an exploratory factor analysis (EFA). Construct validity was examined by testing predefined hypotheses on relationships between the SES-G and total- and subscores of the SER-G, HOOS, HSS-HRES. The SES-G was readministered after two weeks to assess test-retest reliability. To evaluate test-retest reliability 2-way random-effects absolute agreement intraclass correlation coefficients and Bland-Altman analysis were calculated. MacDonald's Omega was used to evaluate internal consistency. Standard error of measurement (SEM) and minimal detectable change (MDC) were explored.

EFA revealed three components explaining 75% of the total variance. For construct validity, 80% of the hypotheses were confirmed. Internal consistency was good (MacDonald's Omega = 0.81), as was test-retest reliability (ICC 0.71). Mean difference between the first and second administrations was -1.6 ± 4.2. The corresponding 95% CI did not contain zero [-2.4, -0.8], indicating systematic bias. Limits of agreement were 6.7 and 9.8. Proportional bias can be ruled out (B = 0.187, p = 0.05). SEM was 3.08, MDC_ind and MDC_group were 5.95 and 0.55, respectively.

The psychometric analysis provides preliminary evidence that the SES-G is a valid and reliable instrument to measure self-efficacy in THA patients.