A pile foundation reconstruction prosthesis for severe acetabular bone defects : principle, design, and mechanical analysis.

Aims: Severe acetabular bone defects generally refer to Paprosky III defects and pelvic discontinuity. Reconstruction surgery for these is complex, and requires innovative strategies to address implant failure and reconstruct the acetabulum. Traditional reconstruction methods rely on the acetabular inner surface bone stock for prosthetic support, which sometimes proves inadequate for reconstructing severe acetabular bone defects. This study proposes a pile foundation reconstruction prosthesis (PFRP) that stabilizes the acetabular component by means of pile screws anchored in the deep periacetabular bone stock, offering a promising solution for addressing severe acetabular bone defects. Methods: This article elucidates the fundamental principles, design, fabrication, and implantation technique of the PFRP, and verifies its mechanical stability through finite element analysis (FEA) and biomechanical testing, exploring its biomechanical characteristics. Results: Initial FEA of the prosthesis determined that the posterior iliac pile and the pubic pile serve as the primary load-bearing components. Furthermore, a minimum triangular configuration of the posterior iliac pile, pubic pile, and ischial pile is required to stably support the acetabular component. Through fatigue mechanical testing and FEA, the efficacy of the PFRP in reconstructing Paprosky IIIB acetabular defects has been validated. Furthermore, a cluster analysis was performed on a historical cohort of 137 acetabular revision cases, categorizing the bone defects into four distinct types. The effectiveness of the PFRP was validated by applying it to the most severe defect within each category, thereby demonstrating its broad clinical applicability. Conclusion: The PFRP exhibits excellent stability. The three-pile fundamental configuration can stably reconstruct acetabular bone defects of various severities. This represents a promising novel strategy for reconstructing acetabular bone defects.