The German version of the Oxford Shoulder Score--cross-cultural adaptation and validation

The evaluation of health-related quality of life is an established criterion for the evaluation of therapeutic measurement. Especially in the English language, a great number of different questionnaires have been developed. The original, English-language 12-item Oxford shoulder score (OSS) is a recently developed and validated patient-completed outcome measure specifically designed for the evaluation of patients suffering from shoulder pathology other than instability. Because of the lack of a comparable instrument in German, this questionnaire was translated into German and subsequently tested for validity and reliability in a cross-sectional study.

Translation of the OSS was done according to the guidelines in the literature. One hundred two patients completed the German version of the OSS and the SF-36. Additionally, the Constant shoulder score and the UCLA shoulder score were included into the validation process. The psychometric properties feasibility and patient-burden parameters were also tested.

The patients completed all questionnaires. The mean time required for completing the OSS was 3 min, 25 s; the mean time required for evaluation of the questionnaire was 35 s. The internal consistency tested by the Cronbach's alpha (0.94) was high. The reproducibility tested by two different methods showed no significant difference. The construct validity showed a significant correlation between the OSS and the other scores.

The instrument proved to be valid by demonstrating the same correlations predicted by standard clinical assessments and a generic patient-based instrument. Application and evaluation in clinical trial proved feasible and minimally time consuming. Therefore, the German translation of the Oxford shoulder score is a valid and reliable tool, applicable to outcome studies on shoulder patients.