Finite element analysis of the stability of combined plate internal fixation in posterior wall fractures of acetabulum.

Objective: This study aims to explore the mechanical stability of combined plate internal fixation in posterior wall fractures of the acetabulum. Methods: The fracture and internal fixation models were established in this study and they were divided into four kinds of internal fixation models, finite element analysis was performed. The four groups were 2 mini-plates and 1 reconstruction plate fixation (A), Reconstruction plate internal fixation group (B), 2 screws internal fixation group (C) and mini-plates internal fixation group (D). The displacement of each node was measured and evaluated. Results: There was no distortion in the geometric shape of the finite element model. The results of stress showed that it was less in the anterior pelvic ring and distributed uniform in labrum acetabulare; the stress was bigger in the upper and middle of sacroiliac joint and sciatic notch in sitting position. Conclusions: Combined plate internal fixation for posterior wall fractures of acetabular were stable and reliable, it is better than the other three methods.