Abstract

Introduction: Kneeling work leads to an additional risk of developing knee osteoarthritis (OA). Previous studies have primarily been based on radiography, but radiography is limited by its inability to visualize articular cartilage, in which the earliest signs of OA occur. The objective of this explorative study, based on available data, was to examine the prevalence of magnetic resonance imaging (MRI)-detected knee cartilage lesions in male floor layers exposed to kneeling work, as compared to non-exposed male graphic designers. Methods: MRI of the knees was conducted in 92 floor layers and 49 graphic designers, with a mean age of 55.6 years (42-70 years). MRI-detected cartilage lesions were graded according to a nine-point lesion scale using a modified Whole Organ Resonance Score (WORMS) system. Severe knee cartilage lesions were defined as a maximal lesion score ≥ 3 in 1) the medial tibiofemoral posterior area, the most strained area during kneeling and 2) the total knee. Presence of lesions was compared in floor layers and graphic designers after adjusting for age, BMI, seniority, knee injuries, and sports activity in logistic regression analyses for correlated data, and investigated as a risk factor for self-reported knee complaints in ordinary logistic regression analyses. Results: The prevalence of MRI-detected knee cartilage lesions did not differ between the two occupations in the tibiofemoral medial posterior area of the knee (p ≥ 0.50), or in the total knee (p ≥ 0.29). For the two study groups combined, age showed a five-fold increase in the odds of cartilage lesions per 10 years' difference in age, and presence of cartilage lesions was associated with a 2.5-fold increase in the odds of self-reported knee complaints. Conclusions: In contrast to our expectations, MRI-detectable knee cartilage lesions were not more prevalent among workers with knee-demanding work. This calls for further research that can clarify the mechanisms that causes knee OA in occupations with knee-demanding work.

Authors and Affiliations