The German version of the Nottingham Clavicle Score is a reliable and valid patient-reported outcome measure to evaluate patients with clavicle and acromioclavicular pathologies

PURPOSE: The Nottingham Clavicle Score (NCS) is a patient-reported outcome measure developed to evaluate treatment results of clavicle, acromioclavicular and sternoclavicular joint pathologies. Valid, reliable and user-friendly translations of outcome measure instruments are needed to allow comparisons of international results. The aim of this cross-sectional study was to translate and adapt the NCS into German and evaluate the psychometric properties of the German version. METHODS: The translation and cross-cultural adaptation of the NCS were completed using a ‘translation–back translation” method and the final version was administered to 105 German-speaking patients. The psychometric properties of this version (NCS-G) were evaluated in terms of feasibility, reliability, validity and sensitivity to change. RESULTS: No major differences occurred between the NCS translations into German and back into English, and no content- or linguistic-related difficulties were reported. The Cronbach’s alpha for the NCS-G was 0.885, showing optimal internal consistency. The Intraclass Correlation Coefficient for test–retest reliability was 0.907 (95% CI 0.844–0.945), with a standard error of measurement of 5.59 points and a minimal detectable change of 15.50 points. The NCS-G showed moderate to strong correlation with all other investigated scales (Spearman correlation coefficient: qDASH: ρ = – 0.751; OSS: ρ = 0.728; Imatani Score: ρ = 0.646; CMS: ρ = 0.621; VAS: ρ = – 0.709). Good sensitivity to change was confirmed by an effect size of 1.17 (95% CI 0.89–1.47) and a standardized response mean of 1.23 (95% CI 0.98–1.45). CONCLUSIONS: This study demonstrated that NCS-G is reliable, valid, reproducible and well accepted by patients, showing analogous psychometric properties to the original English version. LEVEL OF EVIDENCE: Level III. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00167-022-07129-6.