Biomechanical Evaluation of a New Fixation Type in 3D-Printed Periacetabular Implants using a Finite Element Simulation

Abstract

Pelvic implants require complex geometrical shapes to reconstruct unusual areas of bone defects, as well as a high mechanical strength in order to endure high compressive loads. The electron beam melting (EBM) method is capable of directly fabricating complex metallic structures and shapes based on digital models. Fixation design is important during the 3D printing of pelvic implants, given that the fixation secures the pelvic implants to the remaining bones, while also bearing large amounts of the loads placed on the bone. In this study, a horseshoe-shaped plate fixation with a bridge component between two straight plates is designed to enhance the mechanical stability of pelvic implants. The aim of this study is to investigate the biomechanics of the horseshoe-shaped plate fixation in a 3D-printed pelvic implant using a finite element (FE) simulation. First, computed tomography (CT) scans were acquired from a patient with periacetabular bone tumors. Second, 3D FE implant models were created using the patient’s Digital Imaging and Communications in Medicine (DICOM) data. Third, a FE simulation was conducted and the stress distribution between a conventional straight-type plate model, and the horseshoe-shaped plate model was compared. In both of the models, high-stress regions were observed at the iliac fixation area. In contrast, minimal stress regions were located at the pubic ramus and ischium fixation area. The key finding of this study was that the maximal stress of the horseshoe-shaped plate model (38.6 MPa) was 21% lower than that of the straight-type plate model (48.9 MPa) in the iliac fixation area. The clinical potential for the application of the horseshoe-shaped plate fixation model to the pelvic implant has been demonstrated, although this is a pilot study.

3D-Printed Titanium Custom-Made Prostheses in Reconstruction after Pelvic Tumor Resection: Indications and Results in a Series of 14 Patients at 42 Months of Average Follow-Up

“…The pelvic ring restoration: several authors sustain the importance of restoring the connection between the sacrum-iliac area, the acetabulum and the symphysis [25,26]; other authors sustain a non-anatomical reconstruction [26,27]. Connection to the symphysis could be a more stable fixation at first (Figure 7B), but in the long term, this technique could increase the risk of osteolysis in the symphysis (Figure 7C) (case 3) and prosthesis loosening.…”

Reconstruction of severe acetabular bone defects with porous metal augment in total hip arthroplasty: A finite element analysis study

“…The detailed material properties of different implants are shown in Table 1. 13,14 The pelvic bone material properties were defined according to the relationship among elastic modulus, density and CT values of bone. Grayscale in medical CT imaging was represented by Hounsfield Units (HU), a 4096-value (12-bit) black-to-white scale with a range of −1024 to −3071 HU.…”

Special Issue on “Biomaterials for Bone Tissue Engineering”

“…In silico biomechanical simulations for biomaterials and implants have also been included in this Special Issue. In particular, Park et al [15] studied 3D periacetabular implants using finite element simulations. Different implant models were generated from computed tomographies and medical images.…”