后交叉韧带作为间接MR影像在前交叉韧带损伤中的诊断价值

Anterior cruciate ligament tears: the significance of posterior cruciate ligament as an indirect MR sign

目的 评价后交叉韧带 (PCL)作为间接MR影像在前交叉韧带 (ACL)损伤中的诊断价值。方法 回顾分析 78例经关节镜证实的膝关节MRI资料 ,其中ACL损伤 3 3例 ,正常 45例。盲法分析MR影像的以下PCL参数 :PCL线、PCL角和PCL指数。结果 阳性PCL线诊断ACL损伤的敏感性和特异性分别是 75 .6%和 97.8% ,PCL角小于 10 9°分别是 66.7%和96.6%。ACL损伤的PCL角为 ( 10 2± 10 .1)° ,正常时PCL角为 ( 116± 9.8)°(P <0 .0 0 1)。ACL损伤时PCL指数为 3 .76± 0 .93 ,正常为 4.95± 0 .63 (P <0 .0 1)。结论 PCL角小于 10 9°和阳性PCL线的高特异性说明可以用其诊断ACL损伤。PCL角度和PCL指数越小 。

Objective To evaluate the significance of MR appearance of posterior cruciate ligament (PCL) as an indirect sign in detecting the tear of anterior cruciate ligament (ACL). Methods MR images of knees in 78 consecutive patients were retrospectively reviewed, among which 33 ACLs were torn and 45 were normal. All the diagnosis of ACL tear was verified by arthroscopy. The following MR signs, including PCL line, PCL angle and PCL index were analyzed blindly. The sensitivity and specificity of each sign were measured to evaluate the diagnostic accuracy. Results The sensitivity and specificity of positive PCL line in detecting the tear of ACL were 75.6% and 97.8%, respectively, and of the PCL angle less than 109° were 66.7% and 96.6%, respectively. The PCL angle in torn ACL was (102±10.1)°, in normal ACL was (116±9.8)°(P<0.001). The PCL index in torn ACL was 3.76±0.93,while in normal ACL was 4.95±0.63 (P<0.01). All of them had significant difference. Conclusion The MR images may help to improve the diagnosis of ACL tear. The high specificity of the presence of PCL angle less than 109° and positive PCL line support the diagnosis of ACL tear. The absence of the above does not exclude the diagnosis completely because of their moderate sensitivity. The smaller of the PCL angle and the PCL index, the more possibility of ACL tears. [