¹Washington University School of Medicine, St. Louis, United States
²University of Angers, Angers, France
³INSERM (L'Institut national de la santé et de la recherche médicale), Paris, France

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Introduction: Knee meniscus disorders represent a significant cause of work absence and work disability, and often result in surgical intervention. Workplace exposures to biomechanical stressors of the knee are a potentially preventable risk factor for the etiology of knee meniscus disorders. To date, no large-scale general population study has assessed knee meniscus disease associated with cumulative workplace exposures over the working lifetime

Methods: Participants in a prospective French general population survey (CONSTANCES) were surveyed between 2012 and 2017. The survey included a history of current and past jobs for each participant, allowing estimation of past and current job exposures using a previously developed job exposure matrix (JEM-Constances). Analyses were restricted to those workers reporting some period of full time work in 1989 or later. For each year of employment between 1989 and 2016, job exposures were assigned using a previously developed Job Exposure Matrix (JEM-Constances) for the duration of exposure to standing, kneeling/squatting, carrying loads > 25 kg, and computer use. Workers in the CONSTANCES study undergoing knee meniscus surgery in this cohort were identified through national health insurance data for the 8 year period 2009–2016. We used Poisson regression models with robust error variance to explore the relationship between work exposures and future meniscus surgery.

Results: 138,440 participants (53.3% women) had a work history available during the study period; most were actively working at the time of the study. The median number of years worked was 22 for men and 20 for women. More men than women had meniscus surgery (1,062 men vs. 541 women). Meniscus surgery was associated with older age, higher BMI, and lower leisure time physical activity. Cumulative years of work in a job above the 75th percentile of population exposures to standing, kneeling/squatting, and carrying loads > 25 kg were associated with statistically significant higher risks of meniscus surgery among men (RR per ten years of exposure 1.06-1.09), while years of computer work were associated with a lower risk of surgery (RR=0.93). Years of standing was associated with higher risk of surgery among women (RR=1.11). Placing a 5 year lag on exposures (not including the last five years of exposure) had minimal effects on the associations.

Conclusion: Our study found that working long hours standing, carrying heavy loads, and kneeling and squatting increased the risk of knee meniscus surgery among men during the working life. Time spent on computers was linked to a lower risk of future meniscus surgery.