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

Abstract

This study aims to evaluate the reconstructive stability for Paprosky III acetabular defects after total hip arthroplasty using three different reconstruction strategies with trabecular metal (TM) augments. The acetabular bone defects examined were located in the ilium, the sciatic ramus and the pubic ramus. Different scenarios of acetabular reconstructions were simulated, including the non-reconstruction model (NRM), the complete reconstruction model (CRM), the two-point reconstruction model (TRM) and the superior edge reconstruction model (SRM). A primary hip replacement model (HRM) was also investigated to compare the initial stability with different reconstruction models. The gait cycle was incorporated in the model to investigate the dynamic variation within the contact mechanics parameters. By comparing the SRM and the TRM, the acetabular cup translation was more pronounced when the superior defect on the acetabulum remained unfixed. Comparison of the acetabular cup displacement and the interface micromotion of both HRM and CRM demonstrated that the prosthetic implant provided good support for the reconstructed acetabulum. With the use of a press-fit cup, the cup displacement was reduced remarkably, while its Von-Mises stress increased significantly. The results show that the CRM was the best reconstruction option. In terms of acetabular defects, future improvements should focus on the reconstructive stability in stress concentration areas, to ensure no significant stress-shielding or other factors contributing to loosening of the prosthesis.

Personalized digital simulation‑assisted acetabular component implantation in revision hip arthroplasty

“…Our group previously used the Mimics software for simulations to assess acetabular prosthesis size, bone defects and acetabular prosthesis coverage in hip dysplasia cases, but in acetabular prosthesis revision, the bone defects resulting from acetabular prosthesis removal need to be considered when reconstructing the simulated surgery owing to the influence of the original acetabular prosthesis ( 39 , 40 ). Therefore, the present research will help to judge the size of the bone defect after prosthesis implantation based on the difference between the ideal acetabular center and the actual acetabular center, to choose whether to add a pad or to solve the problem of limb shortening by replacing the ceramic ball head, which is relatively simple and easy to operate and promote the use of.…”

Extended Fixation for Paprosky Type III Acetabular Defects in Revision Total Hip Arthroplasty with a Minimum Follow‐Up of 2 Years

“…Porous metal augments have provided a promising solution 6,9–13 . The metal augments are made from tantalum or titanium alloy with high porosity and low Young's modulus, which features excellent biocompatibility, improved capacity of osteointegration, and good initial stability for fixation while avoiding stress shielding 13–17 . Jenkins et al .…”

“… 6 , 9 , 10 , 11 , 12 , 13 The metal augments are made from tantalum or titanium alloy with high porosity and low Young's modulus, which features excellent biocompatibility, improved capacity of osteointegration, and good initial stability for fixation while avoiding stress shielding. 13 , 14 , 15 , 16 , 17 Jenkins et al . described three basic techniques of using metal augments, namely “flying buttress,” “dome,” and “footing.” 18 However, this classification does not reflect the mechanical principles of applying augments, especially those extending to the level of the sacroiliac joint, like buttress augments and stacked slope augments.…”

RSA Measurements of Implant Instability in a Paprosky III Pelvic Defect with Discontinuity

“…Although improvements in survivorship have been reported 7,8 , questions remain about consistently achieving initial cup stability and osseointegration in every case, especially in those with significant defects and poor bone quality 1 . In cases where press-fit cannot be achieved, 3-point fixation has been proposed to be a requirement to achieve acetabular component stability 9,10 and the importance of good inferior, ischiopubic, and iliac fixation has been recently raised [11][12][13] .…”