Comparative Finite Element Analysis of Three Acetabular Plate Designs with Different Bridge Geometries.

Abstract

Background: Acetabular fractures are complex injuries of the hip joint. Careful design of fixation plates is crucial for achieving stable osteosynthesis, especially in patients with poor bone quality. Finite element analysis (FEA) is widely used for biomechanical evaluation of orthopedic implants.

Objective: The aim of this study was to perform a comparative finite element analysis of three acetabular plate designs differing in bridge geometry and to identify the configuration with the most favourable biomechanical performance. We hypothesized that a plate with two parallel bridges would provide more favourable stress distribution and a higher safety factor compared to single-bridge and non-parallel-bridge designs.

Methods: A three-dimensional model of the pelvic bone was reconstructed from CT data. Three titanium alloy (Ti-6Al-4V, thickness 2.5 mm) plates with different bridge configurations (single bridge, two parallel bridges, two non-parallel bridges) were virtually implanted using CAD software (KOMPAS-3D, Autodesk Inventor). The FEA model included cortical and cancellous bone with mechanical properties taken from the literature. A load of 250 N applied at 15° to the inner plate surface simulated partial weight-bearing in the early postoperative period. Von Mises equivalent stress, linear displacement, and safety factor were evaluated.

Results: Maximum von Mises equivalent stresses were 207 MPa for the single-bridge plate, 170 MPa for the two-parallel-bridge plate, and 344 MPa for the two-non-parallel-bridge plate. The corresponding minimum safety factors were 1.33, 1.62, and 0.8. The obtained stress values are consistent with findings from similar studies.

Conclusion: The plate with two parallel bridges exhibited the highest safety factor and appears to be the most promising candidate for further experimental evaluation based on the present computational findings. The single-bridge and two-non-parallel-bridge designs require further design modification, particularly in the bridge cross-sections, because of their lower static safety margins. FEA is a useful tool for comparative biomechanical assessment of implant designs.