Experimental Verification of Finite Element Computer Modeling of Distal Radius Locking Bridge Plate for Treatment of Distal Radius Fracture

Abstract

This study aims to produce experimental data on the mechanical properties and modes of failure of a distal radius locking bridge plate in simulated distal radius fracture (DRF), both independently and screwed to synthetic bone, loaded in a similar loading configuration as reported in patients. These data will be used to validate a finite element analysis (FEA) model of the same fracture fixation construct under similar loading conditions in future studies. Two biomechanical in-vitro experiments were performed using composite radius and fused hand Sawbones to represent patient anatomy. The plate is installed by a registered orthopedic surgeon using a surgical guide provided by the manufacturer. After plate installation, a one-centimeter gap is osteotomized in the metaphysis region and replaced with rubber. A static loading test in a cantilever arrangement was performed on this assembly, as well as on an isolated plate, held in a custom-made jig in which the sample was fixed proximally. The isolated plate showed plastic deformation at 46.5 Newtons, and the assembly deformed at between 65 and 90 Newtons. Plastic deformation is measured using strain and force gages. These tests measure data at one sample per second, and the rate of change of this data can be studied as a correspondence to spring constant. These values can be compared to show consistency and are elucidated below. Confidence in these results is verified by mathematical modeling which approximates the isolated plate as a simply supported beam. In the case of this simplified model, the isolated plate would deform at 27 N. This is a ballpark approximation that shows that measurements are on the right order of magnitude. These data collected give evidence that the experimental setup gives repeatable results in multiple iterations, which are usable for finite element analysis to be conducted in the future.M.S., Mechanical Engineering and Mechanics -- Drexel University, 201