Meniscus body position in the normal knee and its change over 4 years

used logistic regression models to evaluate if the presence of JSN or worsening of JSN (JSN progression), as dichotomous outcomes, were associated with BML volumewhile controlling for sex, body mass index, and age. We also used classification and regression trees (CART) to assess whether baseline BML volume or BML volume change was more influential in predicting JSN progression. To confirm the primary results we used data from the clinical trial (n 1⁄4 103) and performed logistic regression models to examine the association between manually measured BML size change (classified as BML regression, no change, or BML progression) and the outcome of cartilage thickness derived from manual cartilage segmentation (stratified into tertiles). Results: Among 362 knees with BML and JSN data, 240 (66%) had JSN at baseline including 25 knees with severe JSN (grade 3) that were excluded from analyses of JSN progression. Larger baseline BML volume was associated with the presence of baseline JSN (odds ratio [OR] 1⁄4 1.5; 95% confidence interval [CI]1⁄4 1.2 1.8) and JSN progression in the same TF compartment (OR 1⁄4 1.3; 95% CI 1⁄4 1.1 1.5). There was a trend that BML regression and BML progression may be associated with greater odds of JSN progression relative to knees with no or minimal changes in BML volume (Table). Sensitivity analyses, excluding knees with more severe lateral JSN, revealed that BML regression in the medial TF compartment was associated with greater odds of medial JSN progression (Table). In CART analyses baseline BML volume was the variable best able to discriminate between those who did and did not have JSN progression. Finally, confirmatory analyses demonstrated that knees with BML regression (OR 1⁄4 2.7; 95% CI 1⁄4 1.0 7.1) or BML progression (OR 1⁄4 2.0; 95% CI 1⁄4 0.9 4.6) had greater odds of cartilage thickness loss. Conclusions: Baseline BML size is an important assessment in knee OA but a reduction of BML size, as measured on traditional MRI, may not be associated with reduced odds of structural changes.