Validation of the Dutch version of the Oxford Shoulder Score

Background: The Oxford Shoulder Score (OSS) is an internationally-used patient-based outcome score. Up to now, it was not validated in Dutch. The purpose of this study was to produce a Dutch translation of the OSS and to test this version in terms of reliability and validity. Methods: Translation of the OSS was done according to the guidelines in literature. One hundred and three patients completed the Dutch version of the OSS. Additionally, the Constant-Murley shoulder score, the (Dutch) Simple Shoulder Test (DSST) score, and SF-36 were included into the validation process. Feasibility and patient-burden parameters were also tested. Results: One-hundred and three patients with general shoulder problems age 55 years (min-max: 21-81 +/- 13yrs), sex ratio 2/3 (f/m) completed the Dutch version of the OSS and the SF-36. Internal consistency tested by the Cronbach's alpha (0.921) was high. Intra-class correlation coefficient was R = .981 (95% confidence interval: .961 - .993) and the mean difference between both tests was 2.7 points (0-8). Construct validity was also tested by the Pearson correlation coefficient and showed a significant correlation (P < .01) between the Dutch version of the OSS and the other scores (DSST 0.61; the Constant-Murley score 0.64 and with most of the SF-36 sub-scores, except for 2 psychometric subscales, namely, mental health (0.15 [P = .123]) and general health (0.10 [P = .316]) Conclusion: The instrument proved to be valid by demonstrating significant correlations predicted by standard clinical assessments (DSST and Constant-Murley scores) and a generic patient-based instrument (SF-36). Application and evaluation in clinical trial proved feasible and understandable. Level of evidence: Level IV, Case Series, Diagnosis Study. (C) 2010 Journal of Shoulder and Elbow Surgery Board of Trustees.