Improving the Stability of a Hemipelvic Prosthesis Based on Bone Mineral Density Screw Channel and Prosthesis Optimization Design

Abstract

In pelvic reconstruction surgery, the hemipelvic prosthesis can cause significant changes in stress distribution due to its high stiffness, and its solid structure is not suitable for osseointegration. The purpose of this study was to identify a novel bone mineral density screw channel and design the structure of the prosthesis so as to improve the distribution of stress, promote bone growth, and enhance the biomechanical properties of the prosthesis. The mechanical characteristics of bone mineral density screw and traditional screw were compared by finite element analysis method, and redesigned by topology optimization. The direction of the newly proposed screw channel was the posterolateral entrance of the auricular surface, ending at the contralateral sacral cape. Compared to the original group, the maximum stress of the optimized prosthesis was decreased by 24.39%, the maximum stress of the sacrum in the optimized group was decreased by 27.23%, and the average strain energy density of the sacrum in the optimized group was increased by 8.43%. On the surface of screw and connecting plate, the area with micromotion more than 28 μm is reduced by 12.17%. On the screw surface, the area with micromotion more than 28 μm is reduced by 22.9%. The newly determined screw channel and optimized prosthesis design can effectively improve the biomechanical properties of a prosthesis and the microenvironment of osseointegration. This method can provide a reference for the fixation of prostheses in clinical pelvic reconstruction.

Reconstruction with 3D-printed prostheses after type I + II + III internal hemipelvectomy: Finite element analysis and preliminary outcomes

“…A maximal stress of 101.6 MPa was observed when standing in the bipedal posture. With regard to stress of the pelvic ring, a peak stress of 44.1 MPa was observed on the upper endplate of the S1 vertebra, which is consistent with intuition and previous research in distribution and scales ( Iqbal et al, 2017 ; Liu et al, 2019 ; Zhou et al, 2022 ).…”

“…The articular surface area limits the sacroiliac joint being inserted with up to three or four screws. Novel bone mineral density channels have been identified for screw insertion to improve the distribution of stress, promote bone growth, and enhance the biomechanical properties of the prosthesis ( Zhou et al, 2022 ). In our study, the orientation of the screws was more empirical.…”

“…The four models were subjected to bipedal standing (Control, Model 1–3_B), and the femoral neck of the healthy and reconstructed sides was constrained symmetrically. An axial load of 2,000 N was imposed on the center of the artificial acetabulum in Model 3 (Model 3_E) to mimic the most loaded circumstance in one gait cycle ( Bergmann et al, 2001 ; Wang et al, 2022 ; Zhou et al, 2022 ). In terms of boundary conditions, the area of the upper surface of the L4 vertebral body was considered to be fully bonded ( Figure 2 ).…”

Design of 3D-printed prostheses for reconstruction of periacetabular bone tumors using topology optimization

“…In contrast, cortical bone exhibits a Young’s modulus typically below 30 GPa, while the modulus of cancellous bone falls below 2 GPa ( Immel et al, 2021 ; Kang et al, 2021 ; Wu et al, 2021 ). The marked dissimilarity in mechanical attributes between the pelvis and the prostheses can instigate stress shielding, leading to complications such as periprosthetic bone resorption, aseptic loosening of prostheses, and periprosthetic fractures ( Kitamura et al, 2005 ; Arabnejad et al, 2017 ; Wu et al, 2021 ; Zhou et al, 2022 ). Earlier investigations of this topic have demonstrated that adaptations in geometric shapes, materials, or the integration of porous frameworks can mitigate prosthetic rigidity, thus tempering stress shielding ( Glassman et al, 2006 ; Iqbal et al, 2019 ; Vance et al, 2019 ; Zhou et al, 2022 ; Rana et al, 2023 ).…”

“…The marked dissimilarity in mechanical attributes between the pelvis and the prostheses can instigate stress shielding, leading to complications such as periprosthetic bone resorption, aseptic loosening of prostheses, and periprosthetic fractures ( Kitamura et al, 2005 ; Arabnejad et al, 2017 ; Wu et al, 2021 ; Zhou et al, 2022 ). Earlier investigations of this topic have demonstrated that adaptations in geometric shapes, materials, or the integration of porous frameworks can mitigate prosthetic rigidity, thus tempering stress shielding ( Glassman et al, 2006 ; Iqbal et al, 2019 ; Vance et al, 2019 ; Zhou et al, 2022 ; Rana et al, 2023 ). Among these strategies, the incorporation of porous architectures not only bestows a diminished elastic modulus but also fosters biological activity, enhancing the amalgamation of prostheses with host bone and promoting soft tissue adherence ( Chen et al, 2018 ; Lv et al, 2021 ).…”