CT在四肢长骨骨不连诊断中的应用价值

Computed tomography for diagnosis of long bone nonunion of extremities

目的评估CT扫描在诊断四肢长骨骨不连中的价值。方法2003年2月至2007年5月间收集四肢长骨骨不连及疑似骨不连患者118例，对其中X线片难以做出明确诊断的33例进行CT扫描。诊断骨折是否愈合的金标准为术中观察（114例接受手术治疗）和连续6个月的随访观察（4例经CT证实骨折已愈合），由资深医生分组对CT结果进行双盲评估，CT诊断骨不连的灵敏度及特异性采用受试者工作特征曲线（ROC）评估。结果CT扫描诊断骨不连具有较高的灵敏度（100％），总的准确率为83．3％。在33例X线不能明确诊断为骨不连的患者中，CT诊断骨不连29例，骨愈合4例；而经手术或随访证实骨不连27例，皮质部分连接2例，骨愈合4例，导致其特异性相对较低（66．7％）。不同专家对CT评估结果的相关系数为0．91（P〈0．001），具有很好的重复性和一致性。结论对于X线片无法做出明确诊断的四肢长骨骨不连患者，CT扫描具有较高的准确性。

Objective To evaluate the diagnostic accuracy of CT （computed tomography） in detecting long bone nonunion of extremities. Methods We collected the clinical data of 118 patients with long bone nonunion or equivocal long bone nonunion of extremities who had been admitted to our department from February 2003 to May 2007. Of them, 33 patients with equivocal findings on plain radiographs underwent CT scanning. Union or nonunion was determined according to either intraoperative findings （in 114 patients who had been operatively treated） or clinical observation of more than 6 months （in 4 patients who had been diagnosed as union by CT）. Their CT scans and plain radiographs were assessed by experienced orthopedists in double blind manner. The sensitivity and specificity of CT scan were evaluated by the receiver operating characteristic curve. Results CT scans displayed very good diagnostic accuracy. The sensitivity of CT scans for detecting nonunion was 100%, and its overall accuracy was 83.3%. The specificity of CT scans for detecting nonunion was 66.7%, for 2 patients who had been diagnosed as nonunion by CT were found in surgery to have a partial union, Intraobserver agreement was high （interclass correlation coefficient = 0.91 ） . Conclusion CT scans have a very good diagnostic accuracy, when a plain radiograph can not determine union or nonunion of a long bone fracture of extremity.