A new combined reduction anatomical plate for the treatment of acetabular anterior column and posterior hemi-transverse fractures: a finite element analysis study

Background: Acetabularanterior column and posterior hemi-transverse fractures pose a significant challenge for orthopaedic surgeons. Traditional treatment methods are associated with high rates of post-operative complications and lengthy surgical procedures. To enhance treatment efficacy, this study developed a novel internal fixation device called the Combined Reduction Anatomical Plate (CRAP) and conducted a finite element analysis to compare its biomechanical properties to those of traditional internal fixation methods. Methods: A standard finite element model of an anterior column and posterior hemi-transverse fracture of the acetabulum was established using finite element software. Subsequently, four different internal fixation devices were applied: CRAP, double-column locking plates (DLP), supra-pectineal quadrilateral anatomical plate (SQAP), and iliositus + anterior column plate (LACP). After determining the boundary conditions and material properties, the model was simulated in three different body positions (standing, sitting, and lying on the affected side) and subjected to vertical downward forces of 200 N, 400 N, and 600 N. Subsequently, the stress distribution and peak values among the four fixation methods were analyzed, and the maximum pelvic displacement and fracture fragment displacement were evaluated. Results: In this study, the CRAP maximum stress on the steel plate and screws was 159.540 N, 160.540 N, 157.050 N, 177.330 N, 64.756 N, and 30.003 N, which was less than that of the SQAP and LACP and greater than that of the DLP. The maximum tangential micromotion of the CRAP was only 0.016 mm, and the maximum displacement of the pelvis was 0.855 mm. The results showed that the new type of plate developed and designed in this study exhibited a relatively uniform stress distribution and high stiffness, providing sufficient strength. However, the four groups showed no obvious difference in tangential fretting. Conclusion: Compared with the other three fixation methods, the newly designed sectional anatomical reduction plate and screws showed a uniform stress distribution, greater rigidity, sufficient strength, and improved mechanical stability. The CRAP can therefore provide sufficient biomechanical stability and help fracture healing.