The value of MR in diagnosis of posterior root tear of the medial and lateral meniscus / 中华放射学杂志

ABSTRACT

Objective To determine the value of MR in the diagnosis of the medial and lateral meniscal posterior root tears.Methods One hundred and twenty one patients underwent arthroscopy and MR of knee examinations were retrospectively reviewed,and all of them did not have the history of knee surgery before the MR examination.MR images were double-blinded,independently,retrospectively scored by radiology residency (doctor 1) and attending radiologist (doctor 2).The likelihood of the meniscus posterior root tear was scored on basis of arthroscopic findings constituted the gold standard.Sensitivity,specificity and accuracy of MR diagnosis of the lateral and medial meniscus posterior root tear by two physicians were calculated,and the consistency of diagnosis results by two physicians was evaluated using the Kappa statistics.Reasons leading to misdiagnosis or missed diagnosis were discussed.Results Thirty three of the 121 patients were diagnosed with meniscus posterior root tears by arthroscopy,including 14 cases of lateral tears and 19 cases of medial tears.The sensitivity,specificity and accuracy in the diagnosis of posterior lateral meniscus root tears (PLMRT) for doctor 1 were 71.4％ (10/14),82.2％ (88/107) and 81.0％ (98/121),respectively,and for doctor 2 were 71.4％ (10/14),86.0％ (92/107) and 84.3％ (102/121).The sensitivity,specificity and accuracy in the diagnosis of posterior medial meniscus root tears (PMMRT) for doctor 1 were 100.0％ (19/19),88.2％ (90/102) and 90.1％ (109/121),respectively,and for doctor 2 were 100.0％ (19/19),95.1％ (97/102) and 95.9％ (116/121),respectively.The Kappa statistics for PLMRT and PMMRT were 0.67 and 0.81,respectively,demonstrating a good interobserver agreement (P＜0.05).The misdiagnosed cases of the PMMRT were 12 for doctor 1 and 5 for doctor 2.There were 4 cases being commonly misdiagnosed by the two doctors,and there were no any missed cases in this study.For the PLMRT,the misdiagnosed cases were 19 for doctor 1 and 15 for doctor 2.Eleven cases were misdiagnosed and 4 were missed by the two physicians.Conclusion MR is a reliable diagnostic tool for detecting posterior root tears of the medial and lateral meniscus.