临床前沿|如何获得更精准的髋关节假斜位片

来源：304关节学术

翻译：任宁涛

整理：骨科在线

一项发表于Hip Int杂志的一项研究显示，在临床中获得的髋关节假斜位片质量可能不一致，标准化能帮助得到更精确的图像。恰当的假斜位片应在髋关节中心之间的距离约为前后（AP）片上相同距离的0.5倍。

正位片上股骨头中心距离与假斜位片上股骨头中心距离之间的几何关系。

股骨头之间的距离，（a）假斜位，（b）正位，通过这些距离之间的比率计算旋转程度。

射线照相足印和假斜位标准体位。受试者先站在第一组足印上进行AP位照相，然后旋转至第二组脚印进行假斜位照相。

作者设计一种髋关节假斜位片的成像方法，在前后3个月各采用现存成像方法和新的成像方法进行髋关节假斜位片检查，并采用Student t检验和方差分析确定两组骨盆旋转的均值和方差。通过C臂获得10个骨盆的正位和旋转图像，验证骨盆旋转的计算方法，测定各假斜位图像髋关节中心距离合AP图像髋关节中心距离的比值（WP/W）。采用组内相关系数（ICC）检验WP/W与骨盆旋转的关系。

不同骨盆旋转程度WP/W比值（虚线95%CI），尸体研究发现65度斜位时WP/W=0.47。

标准化方法实施后骨盆旋转的准确度和精确度出现显著差异的统计盒型图。

研究对象人口统计学情况

结果显示平均WP/W为0.47 (95% CI, 0.45-0.49)。现存方法组（47.6°；95%CI，45.6-49.5°）和新方法组（60.0°；95%CI，58.7-61.3°）的平均骨盆旋转度有显著性差异（p<0.0001）。此外，与新方法组（SD=5.7，p=0.0035）相比，现存方法组（SD=7.9°）的测量值分布更广。

原文摘要：

Assessing precision and accuracy of false-profile hip radiographs

Purpose: The purpose of this study was to assess the accuracy and precision of pelvic rotation in existing false-profile (FP) radiographs and to devise a method to improve accuracy and precision of FP radiographs.

Methods: An imaging protocol was developed to obtain FP radiographs. Pelvic rotation was calculated using the described method for FP images obtained in the 3 months prior to and after implementation of this protocol. Student's t-test and variance ratio tests were used to determine differences in mean and variance of pelvic rotation between the 2 cohorts. Pelvic rotation calculation methodology was validated by using fluoroscopic C-arm to obtain AP and rotated images of 10 osteologic pelvises. The ratio of the distance between hip centres of each rotated image and AP image (WP/W) was determined. Intraclass coefficient correlation (ICC) was used to verify the relationship between WP/W and pelvic rotation.

Results: Mean WP/W was 0.47 (95% CI, 0.45-0.49). There were significant differences in mean pelvic rotation of the pre-protocol group (47.6°; 95% CI, 45.6-49.5°) and the post-protocol group (60.0°; 95% CI, 58.7-61.3°, p < 0.0001). Additionally, there was a significantly wider distribution of measurements in the pre-protocol group (SD = 7.9°) compared to the post-protocol group (SD = 5.7°, p = 0.0035).

Conclusions: The quality of FP radiographs obtained in the clinical setting may be inconsistent. Standardising FP imaging produces more accurate images. Appropriate FP radiographs should have a distance between hip centres that is approximately 0.5 times the same distance found on an anteroposterior (AP) radiograph.

文献出处：

Ryan T Li , Mithun Neral , Heath Gould , Emily Hu , Raymond W Liu , Michael J Salata . Assessing precision and accuracy of false-profile hip radiographs. Hip Int. 2019 Sep 23:1120700019877848. doi: 10.1177/1120700019877848.