外踝骨折后三角韧带损伤程度的X线与MRI比较研究

A comparative study of degree of the deltoid ligament injury based on X-ray and MRI after lateral malleolus fracture

目的探讨急性外踝骨折后X线片与MRI评价三角韧带损伤程度的影像学诊断价值。方法总结医院PACS系统中41例急性外踝骨折（排除合并内踝骨折病例）的X线片和MR影像资料，于踝穴位X线片上测量踝内侧间隙（medialclearspace，MCS）宽度，应用MR影像对三角韧带深层（胫距后韧带）及浅层（胫弹簧韧带和胫跟韧带）损伤进行评价分级，统计分析MCS与三角韧带损伤程度的相关性；分别记录以x线片和MRI为参考的全部病例Lauge—Hansen分型。结果MCS与三角韧带损伤等级呈正相关，经ROC曲线分析，判定三角韧带完全断裂（深层和浅层同时）的MCS最适临界值和深层单独完全断裂的MCS最适临界值均为7．85mm；而判断浅层完全断裂的MCS最适临界值是6．48mm；以MRI为金标准，所有病例Lauge—Hansen分型的准确性为58．5％，但预测三角韧带断裂的准确性达82．9％，只是难以区分深层和（或）浅层断裂。结论急性外踝骨折后即使未出现内踝骨折，也常伴有三角韧带损伤，X线片仍是踝关节骨折评价的首选检查技术，而MR检查是明确三角韧带损伤程度的敏感辅助检查技术。

Objective To investigate the value of X-ray and MRI in judging degree of the deltoid ligament injury after lateral malleolus fracture. Methods The data of X-ray and MRI of 41 patients with a- cute lateral malleolus fracture, excluding patients combined with medial malleolus fracture, were retrospec- tively analyzed. The medial clear space （MCS） was measured according to the mortise X-rays. The degree of injury of the superficial deltoid ligament and deep deltoid ligament was graded according to MRIs obtained from PACS （picture archiving and communication system） system. Moreover, the correlation between the width of the MCS and the degree of the deltoid ligament injury were statistically analyzed. The classification results of all patients according to the Lauge-Hansen classification based on X-rays and MRIs were recorded, respectively. Results A positive correlation was found between the width of the MCS and the degree of the deltoid ligament injury, and the optimal critical value of MCS was 7.85 mm for diagnosing complete rupture of the total deltoid ligament or the single rupture of the deep deltoid ligament, while 6.48mm for the com- plete rupture of the superficial deltoid ligament. Based on the MRIs, the accuracy of the results of Lauge- Hansen classification was 58.5%, and the accuracy for predicting the rupture of the deltoid ligament was 82.9%, however the degree of the deltoid ligament injury cannot be distinguished very well. Conclusion The deltoid ligament injury is common in acute lateral malleolus fracture, even though there is no medial malleolus fracture. The X-ray is still the preferred choice for the evaluation of the ankle fracture; however the MRI is helpful in judging the degree of the deltoid ligament injury.