Westberry David E, Carpenter Ashley M
Motion Analysis Center.
Shriners Hospitals for Children, Greenville, SC.
J Pediatr Orthop. 2019 Nov/Dec;39(10):521-526. doi: 10.1097/BPO.0000000000001046.
Biplanar radiography with 3-dimensional (3D) modeling (EOS) provides a comprehensive assessment of lower limb alignment in an upright weight-bearing position with less radiation than conventional radiography. A study was performed to assess the consistency and reliability of 2 lower extremity 3D biplanar radiograph models created at least 1 year apart in a pediatric population.
All patients who had 2 lower extremity radiographic evaluations with EOS performed at visits a minimum of 1 year apart were reviewed. Digital radiographs, of lower extremities in both frontal and sagittal planes, were acquired simultaneously, using the EOS system. The 3D reconstruction of the images was achieved utilizing the SterEOS software. Pelvic position, femoral and tibial anatomy, and the torsional profile were evaluated and compared using t tests.
In total, 53 patients with a mean age of 11.7 years (range, 6.1 to 18.9 y) met inclusion criteria. When comparing 3D models between visits, minimal differences were noted in proximal femoral anatomy and pelvic alignment (pelvic incidence, sacral slope, sagittal tilt, neck shaft angle). Expected differences in femoral and tibial length corresponded with normal longitudinal growth between visits. Sagittal plane knee position varied widely between examinations. Femoral and/or tibial rotational osteotomies were performed in 37% of extremities between examinations. After femoral derotational osteotomy, a significant difference in femoral anteversion was appreciated when comparing preoperative and postoperative 3D models. However, this difference was less than the expected difference based on the anatomic correction achieved intraoperatively. No differences were noted in tibial torsion measures after tibial derotational osteotomy.
The 3D modeling based on biplanar radiographs provides consistent and reliable measures of pelvic and hip joint anatomy of the lower extremity. Patient positioning may influence the reproducibility of knee alignment. The torsional profile assessment did not accurately reflect changes obtained by derotational osteotomy.
Level III.
双平面X线摄影与三维（3D）建模（EOS）能够在站立负重位对下肢力线进行全面评估，且辐射量低于传统X线摄影。本研究旨在评估在儿科人群中，间隔至少1年创建的两种下肢3D双平面X线摄影模型的一致性和可靠性。
回顾所有至少间隔1年进行两次下肢EOS影像学评估的患者。使用EOS系统同时获取下肢正位和矢状位的数字X线片。利用SterEOS软件对图像进行三维重建。采用t检验评估并比较骨盆位置、股骨和胫骨解剖结构以及扭转情况。
共有53例平均年龄11.7岁（范围6.1至18.9岁）的患者符合纳入标准。在比较两次检查的3D模型时，近端股骨解剖结构和骨盆对线（骨盆倾斜度、骶骨坡度、矢状面倾斜、颈干角）差异极小。两次检查之间，股骨和胫骨长度的预期差异与正常纵向生长情况相符。矢状面膝关节位置在不同检查之间差异很大。两次检查之间，37%的下肢进行了股骨和/或胫骨旋转截骨术。股骨旋转截骨术后，比较术前和术后3D模型时，股骨前倾角有显著差异。然而，该差异小于基于术中解剖学矫正预期的差异。胫骨旋转截骨术后，胫骨扭转测量无差异。
基于双平面X线片的三维建模为下肢骨盆和髋关节解剖结构提供了一致且可靠的测量方法。患者体位可能会影响膝关节对线的可重复性。扭转情况评估未能准确反映旋转截骨术所导致的变化。
三级。
