Biomechanical study of embracing and non-embracing rib plates

The study was carried out to explore the biomechanical properties of embracing and non-embracing rib plates. Forty-eight adult cadaver rib specimens were divided randomly into six groups: three fixation model groups were made using embracing plates (two pairs of equals on both sides of the broken end), and the other three groups were fixed with a pre-shaped anatomical plate (three locking screws on each side of the end were equally spaced). The biomechanical properties of these models were analyzed using non-destructive three-point bending tests, non-destructive torsion experiments, and destructive axial compression tests. In this study, the gap of fracture ends was widened in embracing plate group in the non-destructive three-point bending experiment. No change in the fracture ends was detected in the pre-shaped anatomical plate group. The bending stress of the pre-shaped anatomical plate group was significantly enhanced at the 2-12 mm displacement points (p < 0.05). Moreover, there was no significant difference in torque noticed between the two groups in the torsion experiment (p = 0.082). In the destructive axial compression experiment, the load index of the two groups were higher than the normal physiological load, suggesting that both materials could provide sufficient strength for rib fractures. The pre-shaped anatomical plate displayed more reliable attachment in terms of stability, bending, and load. Our results indicated that the embracing plate has the advantage of fretting at the fracture end.