Anatomical Risk Factors Of Medial Meniscus Posterior Root Tear

Objectives: The aim of this study was to investigate the effect of anatomical parameters of the medial femoral condyle and tibial plateau on the risk of medial meniscus posterior root tear.Methods: Patients who underwent knee MRI examination in our hospital due to knee pain from January 2016 to January 2020 were selected.Finally,52 patients diagnosed with medial meniscus posterior root tear（observation group）and 40 patients without bone were selected.and patients with abnormal soft tissue anatomy（control group）.The knee joint anatomical parameters of the two groups of patients were measured on the MRI examination images,the medial tibial plateau angle（Medial Tibial Slope,MTS）,the medial tibial plateau depth（Medial Tibial Plateau Depth,MTPD）,the medial femoral condyle anteroposterior diameter（Medial Femoral diameter）were measured.Condyle Length,MFCL),Medial Tibial Plateau Length（MTPL）,Medial Femoral Condyle Width（MFCW）,Medial Tibial Plateau Width（MTPW）.The ratio of the transverse diameter of the medial femoral condyle to the medial tibial plateau（MFCW/MTPW）and the anterior-posterior diameter ratio of the medial femoral condyle to the medial tibial plateau（MFCL/MTPL）were calculated.The differences in anatomical parameters between the two groups were compared,and receiver operating characteristic（ROC）curve analysis was performed to calculate the critical value for the diagnosis of medial meniscus posterior root tear,and to evaluate the diagnostic performance of each anatomical parameter.Results: There were significant differences in MTS,MTPD,MFCW,MFCL,MFCW/MTPW,MFCL/MTPL between the observation group and the control group（p<0.05）.Patients in the medial meniscal posterior root tear group had greater MTS（6.6± 2.1）,MFCW/MTPW（0.87 ± 0.06）,MFCL/MTPL（1.32 ± 0.10）,and smaller MTPD compared with patients in the control group（1.6±0.7）.Among all the risk factors affecting medial posterior root tear,the area under the curve of MFCW/MTPW was the largest AUC: 0.81（95%CI: 0.72-0.89）,when the cut-off value was 0.85,the diagnosis of medial posterior root tear was The sensitivity of fission was 57.69% and the specificity was 97.50%.The area under the curve（AUC）of MFCL/MTPL was 0.71,the best cut-off value was 1.29,the sensitivity was 61.54%,and the specificity was 95.00%.The area under the curve of MTS was 0.78,the best cut-off value was 5.4,the sensitivity was 78.85%,and the specificity was 65.00%.The area under the curve of MTPD was 0.79,the best cut-off value was 2.1,the sensitivity was 82.69%,and the specificity was 62.50%.Conclusion: MTPD is less than 2.1;MTS is greater than 5.4;MFCW/MTPW is greater than 0.85;MFCL/MTPL is greater than 1.29,which are important risk factors for the occurrence of medial meniscus posterior root tear;Measurement of these anatomical parameters in coronal and sagittal views of knee MRI has high sensitivity and detection rate for the diagnosis of medial meniscus posterior root tears.In addition,it is helpful for clinicians to identify individuals who are prone to damage to the posterior root of the medial meniscus,and carry out targeted preventive education.