Current issues in case definitions of common musculoskeletal disorders among workers in clinical practice and research

Several reviews and attempts to conduct a meta-analysis of work-related musculoskeletal disorders have illustrated the problem of comparing different studies of work-related musculoskeletal disorders since different case definitions were used. Thus, valid case definitions for general use among researchers are crucial to making scientific advances. Furthermore, valid case definitions are also required to develop and compare different methods for primary (prohibiting the onset of disease), secondary (curing or treatment) and tertiary (alleviating suffering) prevention. There have been several successful expert committees that have proposed case-definition criteria. None concerning neck and upper extremity disorders has gained worldwide acceptance. The Québec Task Force on spinal disorders was successful in developing a simplified classification based mainly on symptoms and signs. To accomplish widespread feasible case-definitions, the involvement and approval of clinicians from different disciplines is necessary. Even if the case definition is to be used in epidemiological research where no detailed clinical diagnosis is planned, there is a need for clinical approval to ensure understanding and relevance of the results. We suggest that the process for a new feasible case-definition system for the neck and upper extremities should start by agreeing on criteria for diagnosing common musculoskeletal disorders in primary care, which should developed by a panel representing the key disciplines. Epidemiological, intervention and health surveillance case definitions may have the clinical diagnosis as a gold standard.