THE PATIENT-REPORTED OXFORD KNEE SCORE IN NON-ENGLISH LANGUAGES: A SYSTEMATIC REVIEW

C. Srikesavan¹, M. Kothadia², M. Shah³, M. Parikh⁴, S. Sabapathy⁵, P. Maheswari⁶

¹University of Oxford, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Oxford, United Kingdom, ²Ashford & St Peters Hospital NHS Foundation Trust, Surrey, United Kingdom, ³Luton MSK and Community Service, United Kingdom, Luton, United Kingdom, ⁴Broad River Rehabilitation, North Carolina, United States, ⁵NHS Gloucestershire, Gloucester, United Kingdom, ⁶Padmashree Institute of Physiotherapy, Bengaluru, India

Background: Clinicians across the world need culturally-relevant and psychometrically-sound patient-reported outcome measures in their language for use in research and clinical settings.The Oxford Knee Score (OKS) is a widely used patient-reported outcome measure of pain and function over the preceding four weeks in people with osteoarthritis of knee or those awaiting knee replacement surgeries. It has 12 knee-specific questions on activities of daily living, with each item scored on Likert scale ranging from 0 to 4.The total score ranges between 0 and 48 with higher scores indicating better function.

Purpose: This study aimed to critically appraise and synthesise the evidence on the translation procedures and measurement properties of non-English versions of the OKS.

Methods: The review protocol was registered on PROSPERO (CRD42018100610). We searched PubMed, MEDLINE, Embase and Google Scholar for studies relating to cross-cultural adaptation and psychometric evaluation of OKS translations. The quality of translation process and psychometric properties were assessed following the guidelines for cross-cultural adaptation of self-report measures and Consensus-based Standards for the Selection of Health Measurement Instruments (COSMIN) quality assessment criteria. We conducted a qualitative synthesis of findings and used GRADE principles to assess the quality of evidence for each measurement property. We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to report the review.

Results: Twenty-one articles with 22 languages published between 2000 and 2022 in English were included. The studies were conducted in 3842 participants (67% women) with knee osteoarthritis or that awaiting knee replacement surgery. The mean age of participants ranged between 52.2 and 78 years. Sample size ranged from 45 to 1200. Twelve language versions followed all the recommended steps of forward translation, synthesis version, backward translation, expert committee review and pilot testing in a small sample of patients. Sixteen language versions did not require any culturally-equivalent modifications. In Japanese and Korean versions, OKS item 5 on the ability to stand up from a chair was slightly modified for cultural-equivalence. Four language versions did not provide any information.
The frequently evaluated measurement properties were internal consistency, reliability, construct validity, and floor and ceiling effects. The Western Ontario and McMaster Universities Index (WOMAC) and Short Form 36 (SF 36) were the common outcome measures that were used to demonstrate construct validity of the OKS. Thirteen language versions reported no floor and ceiling effects and five observed individual-item level effects. Three language versions reported measurement error; four evaluated responsiveness; and six performed factor analysis. The quality of evidence across the different language versions was high for internal consistency and validity, and moderate for reliability.

Conclusions: The majority of non-English versions of OKS followed adequate translation and cross-cultural adaptation procedures, and provided evidence for validity and reliability properties.

Implications: The Oxford Knee Score has been formally adapted in 22 languages and shown to be a reliable and valid measure in many diverse cultures. Further supplementary evaluations are needed to demonstrate measurement error, responsiveness and structural validity.

Funding acknowledgements: This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Keywords:
Oxford Knee Score
Cross-cultural adaptation
Patient-reported outcome measure

Topics:
Musculoskeletal: lower limb
Disability & rehabilitation
Rheumatology

Did this work require ethics approval? No

Reason: This is a systematic review and hence did not need ethics approval.