Simulation of the Effect of Flexible and Rigid Plate Designs on Murine Fracture Healing

Although several histological studies in mice have examined healing of fractures secured with bone plates, no data are available at present on the mechanical response of fractured bone or callus tissue. Here, we simulated the healing response of fractures secured with rigid and flexible bone plate-designs. Using finite element methods, we simulated the maximum principal strain, stress, and strain energy density in the fractured region of mouse femurs under three loading conditions. In the rigid plate-design, the strain energy density increased when compression and bending were loaded and decreased when torsion was loaded. In the flexible plate-design, the strain energy density increased under all loading conditions. Since an increase in the strain energy density indicates an increase in mechanical stimulation, the simulation suggests that the flexible plate design may stimulate bone growth more than the rigid plate design. A favorable bone plate design must be stiff enough to avoid dislocation but flexible enough to provide mechanical stimulation.