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To assess the prevalence of upper extremity work-related musculoskeletal disorders (WMSDs) among surgical device mechanics compared to a control group, a total of 70 employees were included and assigned to three occupational groups (grinders, packers, and control). Personal factors, work exposure, manual skill, and complaints were assessed by two self-administered questionnaires and an industry test. WMSDs were diagnosed in a standardised clinical examination. The two-one-sided t-tests (TOST) procedure was used to test the clinical equivalence of the respective grinding and packaging groups vs. the control group in terms of the Disabilities of the Arm, Shoulder and Hand (DASH) score. Thirty-nine study participants (56%) experienced at least one WMSD at the elbow, forearm, and/or wrist, mainly with signs of epicondylitis and nerve entrapment at the medial elbow. The risk of grinders developing upper extremity WMSD was about 2.5-times higher and packers had an 8.6-fold higher risk of a clinically relevant DASH > 29 compared to the control group. However, these differences were not statistically significant. The groups were also proven to be clinically equivalent in terms of DASH score. Surgical device mechanics do not seem to have worse DASH values or be at higher risk of upper limb WMSDs compared to a control group. This is the first study to analyse and compare different workplaces in this industry that are also common in other industries.

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A wide range of endpoints and methods of analysis can be observed in occupational health studies in the context of work-related musculoskeletal disorders (WMSDs). Comparison of study results is therefore difficult. We investigated the association between different clinical endpoints and the presence of upper extremity WMSDs in a healthy working population. Furthermore, the influence of socio-demographic, work-related, and individual predictors on different endpoints was examined. Two self-administered questionnaires were distributed to 70 workers and employees. In addition, a standardized physical examination and an industry test were performed in this cross-sectional study. Correlations between WMSDs and clinical endpoints were analyzed with the Spearman method and prediction ellipses. Multiple regression models were used to study the strength of associations with a pre-defined set of potential influencing factors. The prevalence of WMSDs was 56% (39/70). Disabilities of Arm, Shoulder, and Hand (DASH) score/pain under strain showed the strongest correlations with WMSDs. When analyzing the correlation between WMSDs and pre-selected predictors, none of the predictors could be identified as a risk factor. The DASH score remains a close candidate for best surrogate endpoint for WMSDs detection. Standardized analysis methods could improve the methodological quality of future occupational health studies.

BackgroundTo investigate the association between different clinical endpoints and the presence of upper extremity work-related musculoskeletal disorders (WMSDs) in a healthy working population. Furthermore, the influence of socio-demographic, work-related and individual predictors on different endpoints was examined.MethodsTwo self-completion questionnaires were administered to 70 workers and employees. In addition, a standardized physical examination and an industry test were performed in this cross-sectional study. Correlations between WMSDs and clinical endpoints were analysed with the Spearman method. Depending on the type of dependent endpoint, linear or logistic multivariate regression models were used to study the strength of associations with a pre-defined set of potential influencing factors.ResultsThe prevalence of WMSDs was 56% (39/70). Correlations between WMSDs and the DASH score / pain under strain (VAS) were by far the strongest ones. Independent predictors could not be identified as risk factors for WMSDs, but there was some correlation between these factors.ConclusionsThe DASH score, used in the primary analysis of the study data, remains a close candidate for best surrogate endpoint for WMSD detection. The VAS has to be examined for this role in further research. Our analysis should help to improve the methodological quality of future occupational health studies through improved standards.Trial registrationThis study was registered at ClinicalTrials.org with the identifier NCT03014128, on January 9, 2017.