Knee osteoarthritis appears to be linked to a lifetime of stress placed on the knees. The first study to estimate the cumulative effects of various activities on the knees has linked housework – but not recreational sports – to the painful condition.
The authors conclude that physical activity in the form of sports is safe, and does not increase the risk of developing knee arthritis. However, heavy-lifting housework could be partially to blame for the rising prevalence of knee arthritis. With new cases nearly doubling in the past two decades, researchers are eager to pinpoint the causes of knee arthritis.
The study involved a questionnaire asking patients about whether they had been diagnosed with knee arthritis, as well as their occupational and recreational history. While previous studies have examined the impact of manual labor occupations on the risk of knee arthritis, this study placed emphasis on the kneeling, lifting, stair climbing, and squatting actions common with housework.
Both men and women who scored in the highest category of total lifetime knee stress were significantly more likely than others to be diagnosed with knee osteoarthritis. However, estimated force on the knees due to sports activity was not seen as a significant factor. The authors conclude that encouraging physical activity does not create an unnecessarily risk for the knees.
Ratzlaff CR, et al. Is lifelong knee joint force from work, home, and sport related to knee osteoarthritis? International Journal of Rheumatology 2012;v.2012 ( 584193): doi: 10.1155/2012/584193.