Liaw Chen-Kun, Wu Tai-Yin, Hou Sheng-Mou, Yang Rong-Sen, Shih Kao-Shang, Fuh Chiou-Shann
Department of Orthopaedics, Shin Kong Wu Ho-Su Memorial Hospital and Health System , Taipei , Taiwan.
Comput Aided Surg. 2013;18(5-6):195-200. doi: 10.3109/10929088.2013.779749. Epub 2013 Mar 25.
Previous work by our group to address the problem of acetabular positioning based on 2D methods resulted in the development of a measurement method with better precision--Liaw's version. This method may help the early diagnosis of acetabular loosening. In the present study, we hypothesized that our computerized ellipse method could improve the precision of measuring acetabular version.
We developed our Elliversion software to measure acetabular version. Using total hip replacement (THR) Simulator, 96 radiographs were synthesized with random femoral inclination and 5° to 52° version, half with the femoral head included and half without. These synthetic radiographs and 28 real radiographs were measured with both Elliversion and the trigonometric method twice by one of the authors with a one-week interval between measurements. We then calculated the difference in the repeated measurements. Student's t-test was used for statistical analysis of the measuring error and inter-measurement difference.
In the precision study, for synthetic radiographs including the femoral head, the ellipse method was significantly better than the trigonometric method (p < 0.01). For synthetic radiographs without the femoral head, there was no significant difference between the ellipse method and the trigonometric method (p = 0.19). As for the repeated measurements, for synthetic radiographs including the femoral head, the ellipse method was significantly better than the trigonometric method (p = 0.001), whereas for synthetic radiographs without the femoral head, there was no significant difference between the two methods (p = 0.17). For real radiographs, there was no significant difference between the two measuring methods (p = 0.12). However, if we excluded the four poor-quality radiographs, there was a significant difference between the two measuring methods (p = 0.04).
We developed a computerized ellipse method for measuring acetabular version on synthetic radiographs and good-quality real radiographs. This method is characterized by its superior precision as compared to the trigonometric method. With the 2D standardized method (Liaw's version), improving the precision of measurement will help earlier diagnosis of acetabular loosening.
我们团队之前致力于解决基于二维方法的髋臼定位问题，由此开发出一种精度更高的测量方法——廖氏版本。该方法可能有助于髋臼松动的早期诊断。在本研究中，我们假设我们的计算机化椭圆法能够提高测量髋臼前倾角的精度。
我们开发了Elliversion软件来测量髋臼前倾角。使用全髋关节置换（THR）模拟器，合成了96张具有随机股骨倾斜度和5°至52°前倾角的X线片，其中一半包含股骨头，一半不包含。这些合成X线片和28张真实X线片由一位作者使用Elliversion和三角测量法各测量两次，测量间隔为一周。然后我们计算重复测量的差值。采用学生t检验对测量误差和测量间差异进行统计分析。
在精度研究中，对于包含股骨头的合成X线片，椭圆法明显优于三角测量法（p < 0.01）。对于不包含股骨头的合成X线片，椭圆法和三角测量法之间无显著差异（p = 0.19）。至于重复测量，对于包含股骨头的合成X线片，椭圆法明显优于三角测量法（p = 0.001），而对于不包含股骨头的合成X线片，两种方法之间无显著差异（p = 0.17）。对于真实X线片，两种测量方法之间无显著差异（p = 0.12）。然而，如果我们排除四张质量较差的X线片，两种测量方法之间存在显著差异（p = 0.04）。
我们开发了一种计算机化椭圆法，用于在合成X线片和高质量真实X线片上测量髋臼前倾角。该方法的特点是与三角测量法相比具有更高的精度。采用二维标准化方法（廖氏版本），提高测量精度将有助于更早地诊断髋臼松动。
