Zanetti Elisabetta M, Terzini Mara, Mossa Luca, Bignardi Cristina, Costa Piero, Audenino Alberto L, Vezzoni Aldo
Elisabetta M. Zanetti, Dipartimento di Ingegneria, University of Perugia, Via Duranti 67, 06125, Perugia, Italy, Phone: +39 075 5853704, Fax: +39 075 585 3606, E-mail:
Vet Comp Orthop Traumatol. 2017 Jul 20;30(4):256-264. doi: 10.3415/VCOT-16-05-0065. Epub 2016 Jun 21.
Double pelvic osteotomy (DPO) planning is usually performed by hip palpation, and on radiographic images which give a poor representation of the complex three-dimensional manoeuvre required during surgery. Furthermore, bone strains which play a crucial role cannot be foreseen.
To support surgeons and designers with biomechanical guidelines through a virtual model that would provide bone stress and strain, required moments, and three-dimensional measurements.
A multibody numerical model for kinematic analyses has been coupled to a finite element model for stress/strain analysis on deformable bodies. The model was parametrized by the fixation plate angle, the iliac osteotomy angle, and the plate offset in ventro-dorsal direction. Model outputs were: acetabular ventro-version (VV) and lateralization (L), Norberg (NA) and dorsal acetabular rim (DAR) angles, the percentage of acetabular coverage (PC), the peak bone stress, and moments required to deform the pelvis.
Over 150 combinations of cited parameters and their respective outcome were analysed. Curves reporting NA and PC versus VV were traced for the given patient. The optimal VV range in relation to NA and PC limits was established. The 25° DPO plate results were the most similar to 20° TPO. The output L grew for positive iliac osteotomy inclinations. The 15° DPO plate was critical in relation to DAR, while very large VV could lead to bone failure.
Structural models can be a support to the study and optimization of DPO as they allow for foreseeing geometrical and structural outcomes of surgical choices.
双骨盆截骨术（DPO）规划通常通过触诊髋关节以及借助X光影像来进行，而这些影像难以准确呈现手术中所需的复杂三维操作。此外，起关键作用的骨应变也无法预先得知。
通过一个能提供骨应力和应变、所需力矩以及三维测量结果的虚拟模型，为外科医生和设计人员提供生物力学指导。
将用于运动学分析的多体数值模型与用于可变形体应力/应变分析的有限元模型相结合。该模型通过固定板角度、髂骨截骨角度以及腹背方向的钢板偏移量进行参数化。模型输出结果包括：髋臼前倾角（VV）和外展角（L）、诺伯格角（NA）和髋臼背侧缘角（DAR）、髋臼覆盖百分比（PC）、峰值骨应力以及使骨盆变形所需的力矩。
分析了超过150种上述参数组合及其各自的结果。针对给定患者绘制了NA和PC与VV的关系曲线。确定了与NA和PC限值相关的最佳VV范围。25°DPO钢板的结果与20°TPO最为相似。随着髂骨截骨倾斜角为正值，输出的L值增大。15°DPO钢板与DAR相关时较为关键，而过大的VV可能导致骨破坏。
结构模型可为DPO的研究和优化提供支持，因为它们能够预测手术选择的几何和结构结果。
