College of Engineering, Peking University, Beijing 100871, China; Beijing 3D Printing Orthopedic Application Engineering Technology Research Center, Beijing 102200, China.
Musculoskeletal Tumor Center, People's Hospital, Peking University, Xizhimen Nan 11#, Xicheng District, Beijing 100044, China.
Clin Biomech (Bristol). 2020 Apr;74:87-95. doi: 10.1016/j.clinbiomech.2020.02.014. Epub 2020 Feb 28.
Reconstructing pelvic type II + III defect caused by bone tumors is challenging. The purpose of this study was to explore the in vitro biomechanical properties of a reconstructed pelvis after periacetabular resection using three-dimensional (3D) printed sacroiliac joint (SIJ) fixed modular hemipelvic endoprosthesis.
Type II/II + III pelvic resection was simulated on an artificial pelvic model. The bilateral acetabulum and pubis were constrained, and the pelvis was maintained in a human physiological standing position. A vertically continuous linear load was applied on the upper face of S1 until obvious unloading or fixed failure occurred. A noncontact optical 3D strain measuring system was used to measure the strains and displacements at the selected area.
The strain at the points of interest did not obviously differ between the intact and reconstructed pelvis models. The difference in the displacement on the reconstructed side was 0.237 mm, and that on the contralateral side was 0.245 mm. The maximum differences in the displacement at the acetabulum were 0.209 mm (vertical) and 0.324 mm (horizontal). A crack at the superior rim of the contralateral acetabulum occurred, and failure loading of 7.126 kN.
The prosthesis in this study showed satisfactory mechanical properties and structural stability. According to the mechanical evaluations, the 3D printed sacroiliac-stabilized hemipelvic endoprosthesis can be used to reconstruct a stable acetabular structure, and there was little influence on the mechanical properties of the surrounding bone structures. The prosthesis design is reasonable, and the mechanical distribution on the reconstructed side was similar to that on the contralateral side.
重建由骨肿瘤引起的骨盆 II 型+III 型缺损具有挑战性。本研究旨在探索使用三维（3D）打印的骶髂关节（SIJ）固定模块式半骨盆假体重建髋臼切除后的骨盆体外生物力学特性。
在人工骨盆模型上模拟 II 型/II 型+III 型骨盆切除术。双侧髋臼和耻骨被约束，骨盆保持在人体生理站立位。在 S1 的上表面施加垂直连续线性载荷，直到明显卸载或固定失效。使用非接触式光学 3D 应变测量系统测量所选区域的应变和位移。
感兴趣点的应变在完整骨盆模型和重建骨盆模型之间没有明显差异。重建侧的位移差异为 0.237mm，对侧的位移差异为 0.245mm。髋臼处的最大位移差异分别为 0.209mm（垂直）和 0.324mm（水平）。对侧髋臼上缘出现裂缝，失效载荷为 7.126kN。
本研究中的假体具有满意的机械性能和结构稳定性。根据力学评价，3D 打印的骶髂稳定半骨盆假体可用于重建稳定的髋臼结构，对周围骨结构的力学性能影响较小。假体设计合理，重建侧的力学分布与对侧相似。
