[A biomechanical study on different fixation of cortical bone plate allograft]

To explore the biomechanical difference between the different fixations of cortical bone plate allograft.

Twenty-seven cadaveric femurs were harvested and were made into the simulated fracture models, which were equally divided into Groups A, B and C. In Group A, the models were fixed with 2 bone plate allografts (110 mm x 10 mm x 3 mm); in Group B, the models were fixed with 2 struts (110 mm x 10 mm x 3 mm) and 5 bone screws; in Group C, the models were fixed with 1 strut (110 mm X 10 mm x 3 mm) and 5 bone screws. The biomechanical tests for the three-piont bending, torsion, and compression were performed. The parameters studied included the values of the displacements in the three-piont bending tests and the compression tests, and the maximum loads during the bending, the compression, and the torsion.

As for all the stiffness parameters tested, Group A showed the greatest displacements among the three groups (P<0.05), except the compressive stiffness parameter, which was similar to that in Group B. The maximum loads of the three-point bending, the torsion, and the compression in Group A were 1.65+/-0.34 kN, 554.3+/-49.34 N, and 7.78 +/-0.82 Nm, respectively; in Group B, they were 1. 12+/-0.37 kN, 428.00+/-37.40 N, and 3.39+/-0.22 Nm, respectively; in Group C, they were 0.71+/-0.46 kN, 218.67+/-36.53 N, and 1.74+/-0.12 Nm, respectively. Group A had a significantly greater strength than the other 2 groups (P< 0.05).

The strength of the cortical bone plate allograft is related to its different fixations. The two cortical bone plate allografts have a greater strength and stiffness than the struts fixed with the bone screws, which can meet the clinical requirement.