膝关节内侧半月板后根部撕裂的MRI表现

MRI findings of posterior root tear of the medial meniscus

目的评价膝关节内侧半月板后根部撕裂的MRI诊断价值。材料与方法回顾性分析经关节镜证实的70例内侧半月板撕裂患者的MR图像,将其中后根部撕裂35例作为后根部撕裂组,其他类型撕裂35例作为对照组,在MR图像横轴面、冠状面及矢状面上评价后根部撕裂的直接征象及其伴随征象,比较2组后根部撕裂征象的发生比例,计算3个平面直接征象对诊断后根部撕裂的敏感度、特异度。结果横轴面放射状撕裂、冠状面"裂隙征"及矢状面"幽灵征"发生比例后根部撕裂组均明显高于对照组(χ2=58.95,P<0.01;χ2=54.96,P<0.01;χ2=45.13,P<0.01),诊断后根部撕裂的敏感度、特异度分别为91.43%、100%;94.29%、100%;85.71%、94.29%。后根部撕裂组半月板半脱位、后根部附着处骨皮质下骨髓水肿发生比例高于对照组(χ2=11.28,P=0.01;χ2=13.03,P<0.01),2组胫股内侧关节软骨损伤发生比例差异无统计学意义(P=0.12),后根部撕裂组关节软骨损伤程度重于对照组(P<0.01)。结论内侧半月板后根部撕裂具有特征性的MRI表现,MRI是诊断内侧半月板后根部撕裂较好方法。

Objective：To determine the value of MRI for diagnosing the posterior root tear of the medial meniscus. Materials and Methods：MR examinations of 70 patients with the posterior root tear of the medial meniscus conifrmed by knee arthroscopies were retrospectively reviewed, including 35 patients with posterior root tear of the medial meniscal （the posterior root tear group） and other 35 patients with medial meniscus tear without root tear （control group）. The direct signs and the accompanying signs of posterior root tear were analyzed in the coronal, sagittal and axial planes of MRI. The incidences of the signs of posterior root tear were compared between two groups, the sensitivity and speciifcity with the direct signs of three planes in detecting posterior roots tear were calculated. Results：The incidences of a radial tear in the axial plane, the crack sign in the coronal and the ghost meniscus sign in the sagittal plane on the posterior root tear group were signiifcantly higher than that on the control group （χ^2=58.95, P〈0.01.χ^2=54.96, P〈0.01.χ^2=45.13, P〈0.01）. The sensitivity and speciifcity with the direct signs of three planes in detecting posterior roots tear were 91.43%, 100%, 94.29%, 100%, 85.71%, 94.29%, respectively. The incidences of the medial meniscus subluxation and the subcortical marrow edema deep to the meniscal root anchor on the posterior root tear group were higher （χ^2=11.28,P=0.01;χ^2=13.03, P〈0.01）. The incidences of cartilage lesion of medial tibiofemoral joint were no difference between two groups （P=0.12）, the severities of cartilage lesion were higher on the posterior root tear group （P〈0.01）. Conclusions：The ifndings of posterior root tear of the medial meniscal were characteristic, MRI is a relatively good method for detection of posterior meniscus root tears.