Association of frequent knee bending activity with focal knee lesions detected with 3T magnetic resonance imaging: data from the osteoarthritis initiative.

OBJECTIVE: To evaluate the association of baseline frequent knee bending activities with the prevalence and progression of cartilage and meniscal abnormalities over 3 years and to assess the effect of frequent knee bending on the different knee compartments with 3T magnetic resonance imaging (MRI).
METHODS: We studied 115 subjects without radiographic knee osteoarthritis (OA) but with risk factors for OA from the Osteoarthritis Initiative database. The inclusion criteria at baseline were age 45-55 years, body mass index of 19-27 kg/m(2) , Western Ontario and McMaster Universities Osteoarthritis Index pain score of 0, and Kellgren/Lawrence grade <2. Knee bending activities (kneeling, squatting, stair climbing, and weight lifting) were assessed by questionnaire at the baseline clinic visit. Cartilage and meniscal abnormalities were graded using the Whole-Organ MRI Score. Logistic regression was used to determine the association of frequent knee bending with cartilage and meniscal abnormalities.
RESULTS: Frequent knee bending activities were associated with an increased risk of prevalent cartilage lesions (odds ratio [OR] 3.63, 95% confidence interval [95% CI] 1.39-9.52), in particular in the patellofemoral compartment (OR 3.09, 95% CI 1.22-7.79). The increase in risk was higher in subjects involved in ≥2 knee bending activities. At 3-year followup, individuals reporting frequent knee bending were more likely to show progression of cartilage damage (OR 4.12, 95% CI 1.27-13.36) and meniscal abnormalities (OR 4.34, 95% CI 1.16-16.32).
CONCLUSION: Frequent knee bending activities were associated with a higher prevalence of knee cartilage lesions (particularly in the patellofemoral compartment) and with an increased risk of progression of cartilage and meniscal lesions in asymptomatic middle-aged subjects.