Steadman Philippon Research Institute, Vail, CO 81657, USA.
The Steadman Clinic, Vail, CO 81657, USA.
Medicina (Kaunas). 2022 May 14;58(5):663. doi: 10.3390/medicina58050663.
: Intraoperative fluoroscopy can be used to increase the accuracy of the acetabular component positioning during total hip arthroplasty. However, given the three-dimensional nature of cup positioning, it can be difficult to accurately assess inclination and anteversion angles based on two-dimensional imaging. The purpose of this study is to validate a novel method for calculating the 3D orientation of the acetabular cup from 2D fluoroscopic imaging. : An acetabular cup was implanted into a radio-opaque pelvis model in nine positions sequentially, and the inclination and anteversion angles were collected in each position using two methods: (1) a coordinate measurement machine (CMM) was used to establish a digitalized anatomical coordinate frame based on pelvic landmarks of the cadaveric specimen, and the 3D position of the cup was then expressed with respect to the anatomical planes; (2) AP radiographic images were collected, and a mathematical formula was utilized to calculate the 3D inclination and anteversion based on the 2D images. The results of each method were compared, and interrater and intrarater reliably of the 2D method were calculated. : Interrater reliability was excellent, with an interclass correlation coefficient (ICC) of 0.988 (95% CI 0.975-0.994) for anteversion and 0.997 (95% CI 0.991-0.999) for inclination, as was intrarater reliability, with an ICC of 0.995 (95% CI 0.985-0.998) for anteversion and 0.998 (95% CI 0.994-0.999) for inclination. Intermethod accuracy was excellent with an ICC of 0.986 (95% CI: 0.972-0.993) for anteversion and 0.993 (95% CI: 0.989-0.995) for inclination. The Bland-Altman limit of agreement, which represents the error between the 2D and 3D methods, was found to range between 2 to 5 degrees. : This data validates the proposed methodology to calculate 3D anteversion and inclination angles based on 2D fluoroscopic images to within five degrees. This method can be utilized to improve acetabular component placing intraoperatively and to check component placement postoperatively.
术中透视可用于提高全髋关节置换术中髋臼部件定位的准确性。然而，由于杯的三维定位，基于二维成像很难准确评估倾斜和前倾角。本研究的目的是验证一种从二维透视图像计算髋臼杯三维方向的新方法。
将髋臼杯顺序植入九个位置的放射性透明骨盆模型中，并使用两种方法在每个位置收集倾斜角和前倾角：（1）坐标测量机（CMM）用于基于尸体标本的骨盆标志建立数字化解剖坐标系，然后用解剖平面表示杯的三维位置；（2）采集 AP 射线图像，并利用数学公式根据二维图像计算三维倾斜和前倾角。比较了每种方法的结果，并计算了二维方法的组内和组间可靠性。
组内可靠性和组间可靠性均很好，前倾角的组内相关系数（ICC）为 0.988（95%置信区间 0.975-0.994），倾斜角的 ICC 为 0.997（95%置信区间 0.991-0.999）。组内可靠性和组间可靠性均很好，前倾角的 ICC 为 0.995（95%置信区间 0.985-0.998），倾斜角的 ICC 为 0.998（95%置信区间 0.994-0.999）。两种方法的准确性均很好，前倾角的 ICC 为 0.986（95%置信区间：0.972-0.993），倾斜角的 ICC 为 0.993（95%置信区间：0.989-0.995）。2D 和 3D 方法之间的误差表示为 Bland-Altman 界限，发现范围在 2 到 5 度之间。
该数据验证了基于二维透视图像计算三维前倾角和倾斜角的方法的有效性，误差在 5 度以内。该方法可用于改善术中髋臼部件的放置，并在术后检查部件的放置。
