Validation of the Chinese (Mandarin) Version of the Oxford Knee Score in Patients with Knee Osteoarthritis.

backgroundWith the increasing number of patients with knee osteoarthritis undergoing TKAs in China, there is a clear need for a valid, short, joint-specific patient-reported outcome measure such as the Oxford Knee Score (OKS). QUESTIONS/PURPOSES: To test the translated and cross-culturally adapted Chinese (Mandarin) version of the Oxford Knee Score (OKS-CV) and its (1) reliability, (2) construct validity, (3) dimensionality, and (4) responsiveness.

methodsThree native Chinese bilingual translators (a professional English translator, an experienced orthopaedic surgeon, an advanced-practice nursing specialist) translated the English-language OKS into Mandarin Chinese. A consensus panel created a synthesis of those efforts, which then was back-translated by two bilingual nonmedical, professional English-language translators. The OKS-CV was developed according to the guidelines of copyright holders. Between March 2013 and March 2015, 253 patients underwent TKAs. Among them, 114 Mandarin-speaking patients with knee osteoarthritis underwent primary unilateral TKA (age, 67 ± 7 years; range, 55-84 years; female, 80%; preoperatively 54% had moderate to severe knee osteoarthritis), completed the preoperative questionnaires, and were followed up, with a mean postoperative followup of 2.7 years (SD, 0.5 years). Eligibility criteria were (1) patients with knee osteoarthritis who were scheduled to have a primary unilateral TKA, (2) patients who were fluent in Mandarin, and (3) consent to participate. The exclusion criteria were: (1) lack of understanding of Mandarin, and (2) inability to comprehend the questionnaires owing to cognitive impairment. To evaluate test-retest reliability, another group of 35 Mandarin-speaking outpatients with knee osteoarthritis (age, 61 ± 10 years; range, 44-84 years; female, 77%) was recruited to complete the OKS-CV twice at a 1-week interval. Reliability was tested using Cronbach's alpha and intraclass correlation coefficient (ICC). Construct validity was evaluated using Spearman's rank correlation coefficient to quantify the correlations between the OKS-CV and the WOMAC, Short Form-8 Health Survey (SF-8

resultsThe internal consistency (Cronbach's alpha = 0.89) and test-retest reliability (ICC = 0.93; 95% CI, 0.87-0.97) proved good. Convergent construct validity was supported by moderate to strong correlations between the OKS-CV and the WOMAC (r = -0.80, p < 0.001), the SF-8

conclusionsThe OKS-CV showed good acceptability and psychometric properties for the intended population. Future studies are needed to evaluate the mental state of patients with knee osteoarthritis. CLINICAL RELEVANCE: The OKS-CV appears to be a reliable, valid, and responsive instrument for Chinese patients with knee osteoarthritis. Based on these results we believe the OKS-CV can be used as a valuable tool for the assessment of patient-reported outcomes in Chinese patients with knee osteoarthritis before and after TKA.