The goal of this study using the biomechanical test was to evaluate the mechanical stability of the bone-plate fixation system according to changes of the fracture gap sizes and widths.

For mechanical test, four types with different fracture models simulating the clinical situations were constructed depending on the gap size (FGS, mm) and the gap width (FGW, %) at the fracture site: 0 mm/0%, 1 mm/100%, 4 mm/100%, 4 mm/50%. For analyzing the effects of fracture gap on the biomechanical stability of the bone-plate fixation system, 4-point bending test was performed under all same conditions.

It was found that the fracture gap sizes of 1 and 4 mm decreased mechanical stiffness by about 50~60% or more. Furthermore, even without fracture gap size, 50% or more fracture gap width considerably decreased mechanical stiffness and suggested the possibility of plate damage through strain results.

Our findings suggested that at least 50% contact of the fracture faces in a fracture surgery would be maintained to increase the mechanical stability of the bone-plate fixation system.