成人症状性外侧盘状半月板损伤对前交叉韧带形态及信号影响的MRI影像学研究

MRI studies on the effects of symptomatic discoid lateral meniscus injury on the morphology and signal of the anterior cruciate ligament in adults

目的报告成人症状性外侧盘状半月板损伤患者前交叉韧带(anterior cruciate ligment,ACL)形态、走形及信号变化特征。方法 2009年5月至2012年5月,经关节镜及MRI证实的成人外侧盘状半月板合并症状性损伤的36膝(外侧盘状半月板损伤组)和经MRI证实的成人外侧盘状半月板无损伤的36膝(对照组)被纳入本研究。应用GE Healthcare Centricity RIS/PACKS系统在MRI冠状面和矢状面上分别测量两组病例ACL长度、下止点宽度及体部宽度,所得数据进行对比研究。以ACL单束或双束纤维走行方向改变、连续性中断、轮廓不清、变细或增粗等MRI影像特征作为ACL形态异常评判标准,以T_2WI系列图像ACL异常高信号作为信号异常评判标准,统计两组病例ACL异常形态及异常信号的发生率并进行比较。结果外侧盘状半月板损伤组冠状面ACL体部宽度(4.89±1.02)mm明显小于无损伤组(5.77±1.13)mm(P=0.004);冠状面ACL长度(19.33±1.49)mm、下止点(7.11±1.19)mm及矢状面ACL长度(33.55±2.76)mm、下止点宽度(15.68±1.40)mm、体部宽度(9.78±1.07)mm与无损伤组比较,差异均无统计学意义(P>0.05)。外侧盘状半月板损伤组ACL正常走行及形态所占比例30.6%明显低于无损伤组77.8%(P=0.000);外侧盘状半月板损伤组在冠状面及矢状面的ACL异常走行及形态发生率分别为52.8%和41.7%,分别与无损伤组冠状面13.9%和矢状面11.1%比较,均明显增高(P<0.05)。外侧盘状半月板损伤组ACL异常信号发生率33.3%也高于对照组11.1%(P=0.023)。结论与无症状、无损伤的成人外侧盘状半月板相比,成人症状性外侧盘状半月板损伤可以导致ACL形态、走行异常和信号改变,其发生可能与外侧盘状半月板损伤、移位并挤压前交叉韧带有关。

Objective To report the morphologic, orientation and signal characteristics of the anterior cruciate ligament （ ACL ） in adults with symptomatic discoid lateral meniscus （ DLM ） injury. Methods From May 2009 to May 2012, 36 knees （ the DLM injury group ） in adults with symptomatic DLM injury confirmed by the arthroscopy and Magnetic Resonance Imaging （ MRI ） examination, and 36 knees （ the control group ） in adults without DLM injury confirmed by the MRI examination were included in this study. General Electric （ GE ） Healthcare Centricity Radiology Information System （ RIS ） / Picture Achiving and Communication System （ PACS ） was used to measure the length, tibial attachment width and body width of the ACL on coronal and sagittal MR images in both groups, and the data were compared. The following MRI characteristics such as orientation changes, discontinuousness, indistinction, diminution and enlargement of single-bundle or double-bundle ACL were taken as the evaluation criteria for abnormal morphology. The abnormally high signal on T2WI of the ACL was taken as the evaluation criterion for abnormal signal. And then the incidences of abnormal morphology and abnormal signal of the ACL were calculated in both groups, and the differences were compared between them. Results The body width of the ACL on coronal images in the DLM injuries group （ 4.89±1.02 ） mm was significantly smaller than that in the controlgroup （ 5.77±1.13 ） mm （P=0.004 ）. The length and tibial attachment width of the ACL on coronal images were （ 19.33± 1.49 ） mm and （ 7.11 ±1.19 ） mm respectively, and the length, tibial attachment width and body width of the ACL on sagittal images were （ 33.55±2.76 ） mm, （ 15.68±1.40 ） mm and （ 9.78±1.07 ） mm respectively, with no statistically significant differences when compared with those in the control group （ P〉0.05 ）. The incidence of normal orientation and morphology of the ACL in the DLM injury group was 30.6%, which was significantly lower than 77.8% in the control group （ P=0.000 ）. The incidences of abnormal orientation and morphology of the ACL on coronal and sagittal images were 52.8% and 41.7% in the DLM injuries group, which were significantly increased when compared with 13.9% and 11.1% in the control group （ P〈0.05 ）. The incidence of abnormal signal of the ACL in the DLM injuries group was 33.3%, which was also higher than 11.1% in the control group （ P=0.023 ）. Conclusions Compared with the adults with intact DLM, the adults with symptomatic DLM injuries could have abnormal morphology, abnormal orientation and signal changes of the ACL, which seems to be related to the extrusion of the ACL caused by DLM injuries and displacement.