Biomechanical Analysis of the Fixation System for T-Shaped Acetabular Fracture

This study aims to evaluate the biomechanical mechanism of fixation systems in the most frequent T-shaped acetabular fracture using finite element method. The treatment of acetabular fractures was based on extensive clinical experience. Three commonly accepted rigid fixation methods (double column reconstruction plates (P × 2), anterior column plate combined with posterior column screws (P + PS), and anterior column plate combined with quadrilateral area screws (P + QS)) were chosen for evaluation. On the basis of the finite element model, the biomechanics of these fixation systems were assessed through effective stiffness levels, stress distributions, force transfers, and displacements along the fracture lines. All three fixation systems can be used to obtain effective functional outcomes. The third fixation system (P + QS) was the optimal method for T-shaped acetabular fracture. This fixation system may reduce many of the risks and limitations associated with other fixation systems

The Influence of Pelvic Ramus Fracture on the Stability of Fixed Pelvic Complex Fracture

This study aims to evaluate the biomechanical mechanism of pelvic ring injury for the stability of pelvis using the finite element (FE) method. Complex pelvic fracture (i.e., anterior column with posterior hemitransverse lesion) combined with pelvic ramus fracture was used to evaluate the biomechanics stability of the pelvis. Three FE fracture models (i.e., Dynamic Anterior Plate-Screw System for Quadrilateral Area (DAPSQ) for complex pelvic fracture with intact pubic ramus, DAPSQ for complex pelvic fracture with pubic ramus fracture, and DAPSQ for complex pelvic fracture with fixed pubic ramus fracture) were established to explore the biomechanics stability of the pelvis. The pubic ramus fracture leads to an unsymmetrical situation and an unstable situation of the pelvis. The fixed pubic ramus fracture did well in reducing the stress levels of the pelvic bone and fixation system, as well as displacement difference in the pubic symphysis, and it could change the unstable situation back to a certain extent. The pelvic ring integrity was the prerequisite of the pelvic stability and should be in a stable condition when the complex fracture is treated

Comparative study on the dynamic response of an out-of-plane gradient bionic sandwich circular plate under two types of impact loading

Out-of-face gradient sandwich structures have been widely studied for their excellent impact resistance. One uniform and two out-of-plane gradient cores are proposed based on the bionic structure of Royal Water Lily, and the midspan deflection of the back panel and the energy absorption of the out-of-plane gradient sandwich structures under various blast loads are studied. Two frequently adopted methods of explosive loading are applied to the sandwich panels, and the responses are contrasted for the loads applied as a time-dependent pressure history versus imposition of the initial velocity. The effect of the fluid–structure interaction is considered in the blast impulsion, and the dynamic responses of the sandwich structures with different out-of-plane density arrangements are analyzed under two loading approaches. Results show that the energy absorption of the core layer under the prescribed velocity approach is approximately 3–5 times that of the applied pressure approach, while the back panel deflections of different out-of-plane gradient sandwiches are similar. There are significant differences in the deformation mechanisms of structures under these two types of impact loads. Under the same type of impact load, the core compression process of the out-of-plane positive gradient sandwich panel is decoupled from the whole tensile bending deformation process of the structure, whereas the core compression process of the out-of-plane negative gradient sandwich panel is strongly coupled with the whole tensile bending deformation process of the structure. The related research will lay the foundation for an in-depth understanding of the theoretical study of the impact of out-of-face gradient sandwich structures

Biomechanical analysis of the fixation systems for anterior column and posterior hemi-transverse acetabular fractures

Objective: The aim of this study was to evaluate the biomechanical properties of common fixation systems for complex acetabular fractures. Methods: A finite element (FE) pelvic model with anterior column and posterior hemi-transverse acetabular fractures was created. Three common fixation systems were used to fix the posterior wall acetabular fractures: 1. Anterior column plate combined with posterior column screws (group I), 2. Anterior column plate combined with quadrilateral area screws (group II) and 3. Double-column plates (group III). And 600 N, representing the body weight, was loaded on the upper surface of the sacrum to simulate the double-limb stance. The amounts of total and relative displacements were compared between the groups. Results: The total amount of displacement was 2.76 mm in group II, 2.81 mm in group III, and 2.83 mm in group I. The amount of relative displacement was 0.0078 mm in group II, 0.0093 mm in group III and 0.014 mm in group I. Conclusion: Our results suggested that all fixation systems enhance biomechanical stability significantly. Anterior column plate combined with quadrilateral area screws has quite comparable results to double column plates, they were superior to anterior column plate combined with posterior screws. Keywords: Acetabular, Anterior column and posterior hemi-transverse, Finite element analysis, Fixation system, Fractur