Cross-cultural adaptation and validation of a Norwegian version of the Goodman Satisfaction Score (GSS-NO) for patients with total hip and knee arthroplasty

BACKGROUND AND PURPOSE: Measuring patient satisfaction after total hip (THA) and total knee arthroplasty (TKA) is important. We aimed to cross-culturally adapt and examine the psychometric properties of the self-reported Goodman Satisfaction Score (GSS) in a sample of Norwegian patients following primary THA and TKA.

METHODS: The GSS was translated and adapted into Norwegian (GSS-NO) following standard guidelines. 800 patients from the Norwegian Arthroplasty Register who had undergone surgery 6-11 months prior were invited to complete GSS-NO and questions on sociodemographic factors, pain, and function in a cross-sectional study. We examined validity in relation to internal structure, response processes, and precision using Rasch analysis, relationships between the GSS-NO and pain and function using Pearson's correlation coefficients, and test-retest reliability using linear weighted kappa statistics.

RESULTS: The GSS-NO was adapted with few challenges. 404 patients (49% THA, 51% TKA) returned complete answers. The GSS-NO met all criteria regarding the rating scale functioning. Local independence among items and unidimensionality was supported and there was acceptable goodness-of-fit. The internal consistency was 0.94. We found no systematic differential item functioning by age, sex, work status, education, cohabitation status, or hip or knee surgery. The correlation coefficients between GSS-NO and pain and function outcomes were 0.79 (95% confidence interval [CI] 0.76-0.82) and 0.79 (CI 0.76-0.82), respectively. Test-retest reliability with weighted kappa ranged from 0.43-0.55 for THA and 0.54-0.81 for TKA.

CONCLUSION: The cross-cultural adaptation of GSS-NO proved to be a valid and reliable measure for use in Norwegian-speaking patients following primary THA and TKA.