Finite Element Analysis of a New Acetabular Plate in the Combined Posterior Column and Posterior Acetabular Wall Fracture Model

Purpose: Fractures of the posterior column and posterior wall acetabulum are the most common pelvic fractures. In this study, we aimed to test the design of a new acetabular plate that combines the spring plate’s function and the plate’s reconstruction. This design should ease fixation and reduce surgery time, but is biomechanically untested. We analyzed this plate using finite element analysis (FEA). Materials and Methods: This observational study compares seven pelvic models: normal pelvis, posterior wall acetabular fracture, posterior column fracture, these two fractures combined, and the three fracture models fixed with the new acetabular plate. The evaluation was based on the analysis of deformation and stress distribution in each pelvic model under a force of 1,000 N directed at 45° from the sagittal and coronal planes. Results: In the normal pelvis, the greatest deformity was found on the ischial tuberosity (up to 3.91 mm and stress distribution tend to be homogenous. The new acetabular plate normalized the deformity and stress distribution to resemble the normal pelvis with highest stress on the ischial tuberosity and inferior side of the acetabulum. The largest deformation was in the middle of the plate and in the screw. Conclusion: The novel plate can normalize stress and deformity in a fractured pelvis and may provide a solution for combining the posterior column and posterior wall of the acetabulum.