Oxford Knee Score: cross-cultural adaptation and validation of the Turkish version in patients with osteoarthritis of the knee

Abstract

Objective: The Oxford Knee Score (OKS) is a valid, short, self-administered, and site- specific outcome measure specifically developed for patients with knee arthroplasty. This study aimed to crossculturally adapt and validate the OKS to be used in Turkish-speaking patients with osteoarthritis of the knee.
Methods: The OKS was translated and culturally adapted according to the guidelines in the literature. Ninety-one patients (mean age: 55.89±7.85 years) with knee osteoarthritis participated in the study. Patients completed the Turkish version of the Oxford Knee Score (OKS-TR), Short-Form 36 Health Survey (SF-36), and Western Ontario and McMaster Universities Index (WOMAC) questionnaires. Internal consistency was tested using Cronbach’s α coefficient. Patients completed the OKS-TR questionnaire twice in 7 days to determine the reproducibility. Correlation between the total results of both tests was determined by Spearman’s correlation coefficient and intraclass correlation coefficients (ICC). Validity was assessed by calculating Spearman’s correlation coefficient between the OKS, WOMAC, and SF-36 scores. Floor and ceiling effects were analyzed.
Results: Internal consistency was high (Cronbach’s α: 0.90). The reproducibility tested by 2 different methods showed no significant difference (p>0.05). The construct validity analyses showed a significant correlation between the OKS and the other scores (p<0.05). There was no floor or ceiling effect in total OKS score.
Conclusion: The OKS-TR is a reliable and valid measure for the self-assessment of pain and function in Turkish-speaking patients with osteoarthritis of the knee.

Keywords

• Clinical assessment; functional status; knee osteoarthritis; Oxford Knee Score; questionnaires.