Age exerts differential effects on MRI misclassification for medial and lateral meniscal tears.

Abstract

The influence of age on magnetic resonance imaging (MRI) misclassification patterns remains incompletely defined. The purpose of this study was to evaluate the association between patient age and MRI diagnostic performance by meniscus compartment, with a focus on error subtype. A retrospective diagnostic accuracy study was performed on 218 patients with intact anterior cruciate ligaments (ACLs) who underwent arthroscopic meniscal surgery between 2020 and 2024 with available preoperative MRI. The primary outcomes were compartment-specific MRI diagnostic errors, including false-positive and false-negative findings, as well as sensitivity and specificity. Univariable logistic regression modelled the association between age (per 10-year increase) and MRI misclassification outcomes, reported as odds ratios (ORs) with 95% confidence intervals (CIs). A total of 218 knees were analysed for both medial and lateral menisci (mean age 46.4 ± 16.3 years; 50.5% male). MRI for detection of lateral meniscal tears demonstrated sensitivity of 0.44 (95% CI, 0.34-0.54) and specificity of 0.57 (95% CI, 0.49-0.66). MRI for detection of medial meniscal tears demonstrated higher sensitivity (0.75; 95% CI, 0.68-0.81) but lower specificity (0.27; 95% CI, 0.17-0.40). With increasing age, sensitivity of MRI for lateral tears declined while specificity increased; sensitivity for medial tears increased while specificity remained low. Each 10-year increase in age was associated with higher odds of lateral false negatives (OR 1.32; 95% CI, 0.99-1.80), although this did not reach statistical significance, and significantly lower odds of medial false negatives (OR 0.48; 95% CI, 0.36-0.62). Receiver operating characteristic analysis showed moderate discrimination for age (area under the curve 0.62-0.80), with thresholds near 46 years. Increasing age was associated with fewer missed medial meniscal tears but more missed lateral tears, with fewer false-positive lateral MRI findings. These patterns may reflect degenerative medial signal changes and lower prevalence of traumatic lateral tears in older patients. Incorporating age with clinical findings may improve compartment-specific MRI interpretation. Level III.