CT横断面测量指标对髌骨脱位的诊断价值

Diagnostic value of CT cross-sectional measurements for patellar dislocation

目的探讨膝关节横断面CT测量TT-TG间距、髌骨倾斜角和髌骨外偏角对髌骨脱位的诊断价值。方法回顾性分析2013年至2016年北京大学第三医院153例髌骨脱位患者和151例对照组患者的临床资料,CT扫描测量胫骨结节-股骨滑车沟(TT-TG)间距、髌骨倾斜角和髌骨外偏角,比较上述指标的组间差异。采用受试者工作特征(ROC)曲线观察各指标的曲线下面积(AUC),并以约登指数最大点作为诊断界值。结果2组患者的年龄、性别、侧别、身高、体重、Insall指数、股骨宽度和胫骨宽度的差异均无统计学意义,髌骨脱位患者的TT-TG间距、髌骨倾斜角和髌骨外偏角分别为(19.4±4.4)mm、(27.5±8.3)°和(42.8±20.7)°,对照组分别为(12.2±4.1)mm、(11.5±6.4)°和(15.6±16.1)°,2组的差异均有统计学意义(P<0.001)。三个测量指标对髌骨脱位的诊断均有价值,AUC均大于0.85,最佳临界值(O0P)分别为15.9 mm、20.8°和31.1°。结论TT-TG间距、髌骨倾斜角和髌骨外偏角对髌骨脱位均具有较好的诊断价值。

Objective To investigate the diagnostic value of knee cross-sectional CT measurements of tibial tuberosity-trochlear groove(TT-TG)distance,patellar tilt angle,and patellar deviation angle for patellar dislocation.Methods From 2013 to 2016,153 patients with patellar dislocation and 151 controls at Peking University Third Hospital were analyzed retrospectively.TT-TG distance,patellar tilt angle,and patellar deviation angle were measured on axial CT images.The performance of TT-TG distance,patellar tilt angle,and patellar deviation angle in predicting patellar dislocation was assessed by the receiver operating characteristic(ROC)curve analysis.Results No significant difference was found between the two groups in age,sex,knee size,height,weight,Insall-Salvati index,femoral width,or tibial width.The mean TT-TG distance,patellar tilt angle,and patellar deviation angle in the patellar dislocation group were 19.4 mm,27.5°,and 42.8°,respectively,which were significantly greater than those of the control group(12.2 mm,11.5°,and 15.6°,respectively).ROC curve analysis suggested that TT-TG distance,patellar tilt angle,and patellar deviation angle could be efficient to diagnose patellar dislocation.All the three measurements had good value in diagnosing patellar dislocation,with the area under the curve values greater than 0.85,and their optimal cutoff values were 15.9,20.8°,and 31.1°,respectively.Conclusion TT-TG distance,patellar tilt angle,and patellar deviation angle have high value in diagnosing patellar dislocation.