Cross-cultural adaption and measurement properties of the Danish version of the Shoulder Pain and Disability Index

Objective: To cross-culturally adapt the Danish version of the Shoulder Pain and Disability Index and to evaluate its measurement properties in terms of reliability and known-group validity. Design: Test-retest study. Setting: Outpatient Clinic of the Department of Orthopaedic Surgery, Regional Hospital Herning, Denmark. Subjects: Consecutive shoulder patients referred to an outpatient clinic. Methods: The Shoulder Pain and Disability Index was translated from English into Danish according to international guidelines. The questionnaire was posted to patients one to two weeks before their scheduled clinical examination and repeated on the day of the examination. Results: A total of 65 patients with a variety of shoulder diagnoses were included in the study. No significant differences were found in scores between the first and the second questionnaire. The minimal detectable change was estimated to 19.4 points, and the intraclass correlation coefficient was 0.88 (95% confidence interval 0.83 to 0.94). Internal consistency measured by Cronbach's alpha was 0.94. The questionnaire was found to discriminate well between currently working and non-working patients. Conclusion: The Shoulder Pain and Disability Index provides a sensitive and reliable tool to assess pain and disability in Danish-speaking orthopaedic shoulder patients.