Diagnostic Efficiency of MRI in Child and Adolescent Lateral Discoid Meniscus

Objective: In the field of diagnosing the adult discoid lateral meniscus (DLM), MRI has undergone extensive research. However, the use of MRI for diagnosing DLM in children and adolescents remains controversial. This study aimed to explore the diagnostic efficiency of MRI for DLM in children and adolescents and to determine the diagnostic value of these indicators. Methods: This retrospective study included children (aged between 4 and 11 years) and adolescents (aged between 12 and 17 years) from September 1, 2019 to January 1, 2023, who were diagnosed with lateral meniscus (LM) or DLM injury through arthroscopic surgery. All patients underwent a 3 T MRI examination before surgery. The MRI indicators included the LM width (LMW), ratio of the LMW to the tibia (RMT), percent coverage of the meniscus (PCM), tibial width (TW), height of the medial tibial spine (HMTS), height of the lateral tibial spine (HLTS), tibial eminence width (TEW), lateral slope angle of the medial tibial eminence (LSAMTE), lateral slope angle of the lateral tibial eminence (LSALTE), and presence of three "bow tie signs." A diagnostic efficacy analysis of all indicators was conducted to determine characteristic MRI diagnostic indicators and analyze their diagnostic value. Pearson's correlation analysis was conducted to evaluate the correlation between diagnostic indicators and baseline information. Results: This study included 90 patients (26 with LM injuries and 64 with DLM injuries). The average age was 12.81 +/- 4.34 years, height was 151.24 +/- 23.82 cm, weight was 48.20 +/- 21.82 kg, and BMI was 19.69 +/- 4.22 kg/m(2). A total of 10 MRI indicators were included and evaluated for their diagnostic value. The comparison between the DLM and LM groups revealed significant differences in LMW, TW, RMT, PCM, LSAMTE, and "bow tie signs" (p < 0.05). In the diagnostic efficacy analysis, LMW had a sensitivity of 85.94%, specificity of 76%, and accuracy of 83.13%; RMT had a sensitivity of 95.31%, specificity of 76%, and accuracy of 89.89%; PCM had a sensitivity of 75.28%, specificity of 60%, and accuracy of 75.28%; LSAMTE had a sensitivity of 72.92%, specificity of 84%, and accuracy of 72.92%; and "bow tie signs" had a sensitivity of 80.95%, specificity of 81.25%, and accuracy of 81.11%. Conclusion: The MRI diagnosis of DLM in children and adolescents can be based on LMW, RMT, PCM, LSAMTE, and "bow-tie signs," with these indicators demonstrating good diagnostic efficacy.