Knee osteoarthritis (OA) is a major cause of pain and disability in women, becoming a major health problem in mid to later life. A better understanding of factors contributing to deleterious structural knee changes may be important for preventing OA. In men, occupations associated with frequent knee bending have been shown to be associated with damage to knee cartilage. This has not been examined in women. The aim of this study was to examine the effect of occupational specific knee activities on tibial and patella cartilage morphology among healthy females.
96 females aged 26-62 years with no history of knee injury or symptoms were recruited as part of a study of community-based study of lifestyle factors on knee health. Occupational activity data examining the frequency of tasks such as heavy lifting, knee bending, stair climbing, walking and standing were obtained by questionnaire. Tibial and patella cartilage volumes and defects were measured from magnetic resonance imaging using validated methods.
Heavy lifting/bending/squatting, knee bending, stair climbing and walking were all associated with an increased risk of patella, but not tibial, cartilage defects (odds ratio 1.8-2.9; p<or=0.05) after adjustment for potential confounders, including knee alignment and radiographic joint space narrowing. There was a trend towards knee bending being associated with a reduction in patella cartilage volume (p=0.07).
Our results demonstrate that asymptomatic adult females with occupations requiring frequent knee bending have patella, but not tibial cartilage damage. These findings suggest that vocational tasks requiring knee bending are detrimental to the structure of cartilage in females and may be an area to consider in the prevention of knee OA.