Inflammation and the pathophysiology of work-related musculoskeletal disorders.

Work-related musculoskeletal disorders (MSDs) have accounted for a significant proportion of work injuries and workers' compensation claims in industrialized nations since the late 1980s. Despite epidemiological evidence for the role of repetition and force in the onset and progression of work-related MSDs, complete understanding of these important occupational health problems requires further elucidation of pathophysiological mechanisms of the tissue response, particularly in the early stage of these disorders. Results from several clinical and experimental studies indicate that tissue microtraumas occur as a consequence of performing repetitive and/or forceful tasks, and that this mechanical tissue injury leads to local and perhaps even systemic inflammation, followed by fibrotic and structural tissue changes. Here we review work linking inflammation and the development of work-related MSDs. We also propose a conceptual framework suggesting the potential roles that inflammation may play in these disorders, and how inflammation may contribute to pain, motor dysfunction, and to puzzling psychological symptoms that are often characteristic of patients with work-related MSDs.