Accurate and consistent mental interpretation of fluoroscopy to determine the position and orientation of acetabular bone fragments in 3D space is difficult. We propose a computer assisted approach that uses a single fluoroscopic view and quickly reports the pose of an acetabular fragment without any user input or initialization. Intraoperatively, but prior to any osteotomies, two constellations of metallic ball-bearings (BBs) are injected into the wing of a patient’s ilium and lateral superior pubic ramus. One constellation is located on the expected acetabular fragment, and the other is located on the remaining, larger, pelvis fragment. The 3D locations of each BB are reconstructed using three fluoroscopic views and 2D/3D registrations to a preoperative CT scan of the pelvis. The relative pose of the fragment is established by estimating the movement of the two BB constellations using a single fluoroscopic view taken after osteotomy and fragment relocation. BB detection and inter-view correspondences are automatically computed throughout the processing pipeline. The proposed method was evaluated on a multitude of fluoroscopic images collected from six cadaveric surgeries performed bilaterally on three specimens. Mean fragment rotation error was 2.4 1.0 degrees, mean translation error was 2.1 0.6 mm, and mean 3D lateral center edge angle error was 1.0 0.5 degrees. The average runtime of the single-view pose estimation was 0.7 0.2 s. The proposed method demonstrates accuracy similar to other state of the art systems which require optical tracking systems or multiple-view 2D/3D registrations with manual input. The errors reported on fragment poses and lateral center edge angles are within the margins required for accurate intraoperative evaluation of femoral head coverage.

荧光检查在3D空间中准确和一致的心理解释很难确定髋臼骨碎片的位置和方向。我们提出一种计算机辅助方法，该方法使用单个透视图并快速报告髋臼碎片的姿势，而无需任何用户输入或初始化。术中但在进行任何截骨术之前，将两个星座的金属滚珠（BBs）注入患者i骨和外侧耻骨上支的翼中。一个星座位于预期的髋臼碎片上，另一个星座位于其余的较大骨盆碎片上。使用三个透视图和2D / 3D配准对骨盆的术前CT扫描重建每个BB的3D位置。通过使用截骨术和碎片复位后的单个荧光透视图估计两个BB星座的运动，可以确定碎片的相对姿势。BB检测和视图间对应关系是在整个处理管道中自动计算的。对从六个标本进行的尸体外科手术，在三个标本上进行双边检查的大量透视图像上评估了所提出的方法。平均碎片旋转误差为2.4 1.0度，平均平移误差为2.1 0.6毫米，平均3D侧向中心边缘角度误差为1.0 0.5度。单视点姿势估计的平均运行时间为0.7 0.2 s。所提出的方法证明了与其他现有技术水平类似的精度，这些技术要求光学跟踪系统或具有手动输入的多视图2D / 3D配准。