With 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).
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.
Three 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
The 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
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.
The 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.