Correlation between body mass index and chondral lesions in isolated medial meniscus tears

BACKGROUND: Chondral lesions of the knee are commonly found during arthroscopic partial meniscectomy. The literature advises against arthroscopic medial meniscectomy in the presence of advanced chondral derangement because of unfavorable outcome. Recent studies have shown an association between obesity and chondropathy in patients with meniscal tears. The aim of this study was to assess whether body mass index (BMI) correlates with the severity of chondral lesions in patients with isolated medial meniscus tears (i.e. without ligamentous or lateral meniscal injury). MATERIALS AND METHODS: 837 knee arthroscopies were performed in a regional referral center of arthroscopic surgery between January 2011 and December 2012. Of these 168 (109 males, 59 females) patients with no axial knee deformity and no radiological signs of osteoarthritis who have had arthroscopic debridement for isolated torn medial meniscus were included in the study. The correlation between different demographic factors and the level of chondral damage reported at surgery was evaluated. The mean age of patient was 50 years (range 13-82 years) and an average BMI was 28.2 kg/m(2) (range17.5-42.5 kg/m(2)). RESULTS: Overall, regression analysis showed both age and BMI to be linearly correlated to chondral score (r = 0.53, P < 0.04); however, there were no advanced chondral lesions found in patients younger than 40 years of age and all severe lesions were at age 50 years or more. Therefore, further analysis was performed for age subgroups: patients were grouped as younger than 40, between the age of 40 and 50 (middle age) and older than 50 years. The BMI was linearly correlated to the severity of chondral score exclusively in the middle aged group (i.e. 40-50 years old). There was no correlation between activity level and chondral damage. Women had worse chondral lesions than men in all age groups. CONCLUSION: Higher BMI in middle aged patients with isolated medial meniscus tears and unremarkable radiographs may predict more advanced chondral lesions at arthroscopy.