The Dutch Version of the Oxford Knee Score – Activity and Participation Questionnaire: A Validation Study

Abstract

Background: Patients undergoing total knee arthroplasty (TKA) tend to be younger and tend to receive TKA at an earlier stage compared to 20 years ago. The Oxford Knee Score – Activity and Participation (OKS-APQ) questionnaire evaluates higher levels of activity and participation, reflecting activity patterns of younger or more active people. The purpose of this study was to translate a Dutch-language version of the OKS-APQ questionnaire, and to validate it in pre- an postoperative TKA patients. Methods: We evaluated the Dutch translation of the OKS-APQ for reliability and validity. Internal consistency, test-retest reliability, factor analysis, construct validity and, floor and ceiling effects were evaluated using quality criteria. The OKS-APQ, the Oxford Knee Score (OKS), the Short Form-36 (SF-36), a Visual Analogue Scale (VAS) for pain and the Forgotten Joint Score (FJS) were assessed in 131 patients, and the OKS-APQ was administered twice in 50 patients after an interval of minimal 2 weeks.Results: Internal consistency (Cronbach α‘s from 0.81 to 0.95) and test-retest reliability (Intraclass Correlation Coefficients (ICCs) from 0.63 – 0.88) were satisfactory to good. The standard Error of Measurements (SEMs) ranged from 8.5 – 12.2 and the Smallest Detectable Changes in individuals (SDCind) ranged from 23.5 – 34.0 (on a scale from 0 to 100). Confirmatory factor analyses (CFA) indices indicated a satisfactory fit of a 1-factor model (Comparative Fit Index (CFI): 0.97, Tucker-Lewis Index (TLI): 0.96, Root Mean Square Error of Approximation (RMSEA): 0.1, Standardized Root Mean Square Residual (SRMSR): 0.03). Construct validity was supported as >75% of the hypotheses were confirmed and floor effects were observed in preoperative patients. Conclusions: The Dutch translation of the OKS-APQ showed good reliability and validity in the Dutch population, and can be used alongside the OKS in clinical research and clinical practice to discriminate among levels of activity and participation in postoperative patients.