Responsiveness, Reliability, and Validity of Arabic Version of Oxford Knee Score for Total Knee Arthroplasty

Background: The Oxford Knee Score (OKS) is a reliable, valid, and sensitive assessment tool for individuals undergoing a total knee arthroplasty (TKA). The published psychometric assessment of the Arabic version of the OKS (OKS-Ar) is limited to male patients and has not been assessed for responsiveness following TKA. The aim of this study was to assess the reliability, validity, and responsiveness of the OKS-Ar in an inclusive population of patients undergoing TKA.

Methods: One hundred Arabic-speaking patients awaiting TKA were assessed with the OKS-Ar, the Arabic version of the Knee injury and Osteoarthritis Outcome Score (KOOS-Ar), and a visual analogue scale for pain (VAS-P) in order to assess the correlation between the OKS-Ar and the KOOS-Ar and VAS-P and determine the construct validity. Repeat assessments were completed 7 to 10 days after the first assessment and 6 months after TKA.

Results: Questionnaires were completed by 80 female and 20 male participants with a mean age of 62 ± 8 years. The test and retest median scores showed no significant difference from one another, with a strong Spearman correlation between the 2 measurements (rs = 0.94). Bland-Altman limits of agreement showed no significant bias. The Cronbach alpha was 0.85 indicating high internal consistency. There was no floor or ceiling effect before TKA, and the post-TKA ceiling effect was only 2%. The OKS-Ar pain component correlated strongly with the KOOS-Ar pain subscale (rs = 0.73). The OKS-Ar effect size was 3.09, which was larger than that of all of the KOOS subscales at 6 months after TKA.

Conclusions: To our knowledge, this is the first study to assess reliability, validity, and responsiveness of the OKS-Ar after TKA. The validity and reliability results are similar to those found for both the original English-language OKS and the OKS translated into other languages. We believe that this is also the first study to assess OKS-Ar responsiveness after TKA and to show a large effect size. We found that the OKS-Ar is a feasible, valid, reliable, and sensitive measurement tool to assess pain and function in TKA-treated individuals whose main language is Arabic.