German translation, cross-cultural adaptation and validation of the Musculoskeletal Health Questionnaire: a cohort study

BACKGROUND: The Musculoskeletal Health Questionnaire (MSK-HQ) was developed to measure the health status of patients with various musculoskeletal conditions across multiple settings including rehabilitation. AIM: Formal translation and cross-cultural adaptation of the MSK-HQ into German (MSK-HQ(G)), to determine test-retest-reliability, standard error of measurement (SEM), smallest detectable change (SDC), construct validity, responsiveness, minimal important change (MIC), and to test for floor or ceiling effects. DESIGN: Cohort study with six weeks follow-up. SETTING: Seven physiotherapy clinics/rehabilitation centres. POPULATION: Patients with a referral for physiotherapy indicating musculoskeletal complaints of the spine or extremities. METHODS: Translation and cross-cultural adaptation were carried out in accordance with guidelines provided by the developers. As reference standards we used pain intensity (0-10 numeric rating scale), quality of life (EQ5D-5L) and disability measures (RMDQ, NDI, WOMAC and SPADI) that were combined using z-scores. RESULTS: On 100 patients (age 44.8 +/- 13.4 years, 66% female) the test-retest-reliability intraclass correlation coefficient was 0.87 (95% CI 0.72; 0.93) and for construct validity correlation with the combined disability measure was r(s)=-0.81 (95% CI -0.88, -0.72), the SEM was 3.4, the SDC (individual) 9.4, and the MIC 8.5. CONCLUSIONS: Overall, the study provides evidence for good reliability and validity for the MSK-HQ(G). Further studies in different settings and diagnostic subgroups should follow to better understand the psychometric properties of this measure in primary care, rehabilitation and specialist care settings. CLINICAL REHABILITATION IMPACT: The results demonstrate that the MSK-HQ(G) has sufficient psychometric properties for use in musculoskeletal research and practice. However, the SDC should be kept in mind when using the tool for individual patients. The MSK-HQ(G) has the advantage of being a single instrument that can measure musculoskeletal health status across different pain sites, reducing the burden from the use of multiple tools.