Factors associated with meniscal body extrusion on knee MRI in overweight and obese women

SummaryObjectiveTo determine factors associated with higher degree of meniscal body extrusion in overweight and obese women at high risk of knee osteoarthritis (OA).DesignWe used baseline data of the PRevention of knee Osteoarthritis in Overweight Females (PROOF) study, Netherlands, comprising overweight or obese women aged 50-60 years, free of clinical knee OA. All subjects completed a questionnaire on knee complaints and physical activity, underwent physical examination, radiography, and 1.5 T magnetic resonance imaging (MRI) of both knees. Using the mid-coronal MRI slice, one blinded observer measured tibial plateau width and meniscal body extrusion of both menisci in both knees. The association between baseline factors and meniscal extrusion, were analyzed with a random effects regression model. In addition, we used a fixed effect regression model for evaluation of knee-specific factors.ResultsMean age of the included women (n = 395) was 55.7 years and mean body mass index (BMI) 32.4 kg/m2. Of all knees, 23% had an absolute medial meniscus body extrusion ≥3.0 mm and 4% had lateral meniscus body extrusion ≥3.0 mm. In the multivariable model, the medial meniscus extrusion was increased by 0.44 mm (95% confidence interval [CI] 0.11, 0.77) when a medial meniscus tear was present, by 0.20 mm per 5 kg/m2 (95% CI 0.05, 0.35) increase in BMI and by 0.25 in the presence of mild knee symptoms (95% CI 0.05 to 0.44). Kellgren-Lawrence (KL) grade ≥1 and tibia width were associated with increased both medial and lateral extrusion.ConclusionIn women, ipsilateral meniscus tear and high BMI are factors associated with medial meniscus body extrusion.