股骨颈前倾角CT三维重建测量的临床研究

Three dimensional reconstruction model measuring femoral anteversion angle

目的探讨三维重建模型,在测量"Y"型软骨已闭合髋臼发育不良患者股骨颈前倾角(femoral neck anteversion,FNA)的价值。方法回顾性分析了2013年3月至2015年6月,在我院诊治的34例髋臼发育不良患者的资料。所有患者完成髋关节至腓骨头水平的CT断层扫描。将.dicom格式存储的CT数据导入Mimics 10.01中,采用表面遮盖显示法重建全股骨三维模型。将重建后的股骨数据以.stl格式导入Geomagic 11.0软件中,选取股骨头侧部分,应用最佳拟合球命令,将股骨头拟合成球体,并记录该球心三维坐标值。股骨头中心坐标输入Mimics软件中,股骨调整至半透明状态,在三维视图上,旋转股骨直至股骨头中心位于股骨颈的投影面积中心。在股骨大转子侧作一与股骨头中心重合的另一点,以直线将两点连接,该线即为股骨颈轴线。旋转股骨直至大转子后缘位于股骨后髁连线中点,做股骨后髁的连线,该连线与股骨颈轴线的夹角即为FNA。2位测试者分别对34例(68髋)用此法测量FNA。采用配对t检验,检验水准α取双侧0.05。结果 34例(68髋)完成股骨全长CT扫描,2位测量者应用上述三维重建法分别对该68髋的股FNA完成测量,其中1位测量者测量2次,两次测量相隔1个月。采用配对t检验。第1次测量时,2位测量者所测量FNA结果分别为(27.83±11.69)和(26.18±15.21),差异无统计学意义(P=0.193)。第1次测量后1个月,2位测量者中的1位,再次对68髋的FNA进行测量。结果为(27.38±11.81),与其第1次测量结果(27.83±11.69)进行配对t检验,差异无统计学意义(P=0.392)。结论三维模型上可以精确寻找股骨头中心、股骨颈轴线等测量基准参数,建立了三维测量FNA的一种方法;在三维重建模型上对FNA的精确测量,为全面认识髋臼发育不良患者解剖学畸形提供了条件,为制订手术方案提供了依据。

Objective To explore the value of the three dimensional（ 3 D） reconstruction model measuring femoral neck anteversion（ FNA） in developmental dysplasia of the hip（ DDH） patients with ＂Y＂ closed cartilage. Methods We analyzed 34 DDH patients diagnosed and treated in our hospital from March 2013 to June 2015. All patients had completed CT scans from the coxa joint to the caput fibular. CT data in dicom format were imported into Mimics 10.01. After the reconstruction of the 3 D model of the femur with surface shaded display, we imported the data in stl format into Geomagic 11.0 software, selected the lateral femoral head to synthesize them into a sphere with the application the best fitting ball command, and recorded the 3 D coordinate of its center. We input the center coordinate of the femoral head into Mimics software. We adjusted the femur to be translucent, and then rotated it until the center of the femoral head reached the center of the femoral neck orthographic projection area on the 3 D view. Making a straight line connect the center of the femoral head with another point which covered the center on the femoral greater trochanter side. And the line was the axis of the femoral neck. Rotating the femur until the inferior border of the greater trochanter was located in the middle of the connection point of 2 femoral condyle infra-glenoid margins. The angle formed by the line and the axis of the femoral neck was FNA. Thirty-four patients（ 68 hips） were respectively measured. The results were analyzed by paired t-test with inspection level alpha 0.05 on both sides. Results All of the 34 patients（ 68 hips） completed the femur CT scans, and 2 testers respectively measured the FNA with the application of 3 D reconstruction mentioned before. One patient was measured twice 1 month apart. Paired t test was used for the statistical analysis. For the first time, the FNA measured by the 2 testers were respectively（ 27.83 ± 11.69） and（ 26.18 ± 15.21）, with no statistically significant differences（ P = 0.193）. The FNA measured by 1 tester 1 month later was（ 27.38 ± 11.81）. No statistically significant differences existed compared with the first measurement results（ P = 0.392）. Conclusions The reconstruction model in 3 D can help to accurately find measurement benchmark parameters, such as the center of the femoral head, femoral neck axis etc, establishing a method of 3 D FNA measurement. The precise measurement of FNA facilitates comprehensive understanding of the anatomical deformities in patients with acetabulum hypoplasia, and provides reference for surgical plan design.