Finite Element Analysis Study of Prototype of a Novel Intramedullary Injectable Bioresorbable Polymer Fixator versus a Volar Plate for Surgical Treatment of Distal Radius Fractures

Abstract

Complications and shortcomings of volar plating, which is very widely used for surgical treatment of distal radius fractures, are well known. Thus, there is scope for alternative innovative surgical methods. In the present work, we used the finite element analysis method to compare the biomechanical performance of a model of a construct comprising a simulated distal radius fracture considered fixated using a notional intramedullary injectable bioresorbable polymer-bioresorbable balloon osteosynthesis system ("fixator") versus using a commercially-available volar locking plate (VP). The biomechanical parameters determined were longitudinal stiffness and factor of safety under each of the applied loads. For the fixator model, 1) each of the biomechanical parameters was markedly influenced by fracture gap fill ratio (FGFR) (defined as the proportion of the volume of the fracture gap that is considered occupied by the expanded polymer-filled balloon) but not by modulus of elasticity assigned to the polymer; 2) with FGFR = 100%, stiffness was comparable to that of the Ti-6Al-4V alloy VP construct model; and 3) stiffness was within the range of literature values for stiffness of constructs comprising simulated fractures in fresh cadaveric distal radii fixated using metal volar locking plate. These results suggest that the fixator may be an alternative modality to metal volar plating and, as such, deserves further evaluation.

Biochemical Finite Element Analysis of the Locked Kirschner Wire System Versus Volar Plate Fixation of Distal Radius Fracture

“…To validate our FE model, the converged results from the model were compared with the experimental results from the fresh cadaveric study and prior FE of distal radius studies. (8,17)…”

“…Bending and torsional loads of 1 Nm and an axial load of 100 N, under the boundary condition and the material properties used in the convergence test, were applied at the end of the distal radius. (8,13,20) Four FE models, two fracture patterns and two fixation methods, were simulated under three load conditions. To study the load transmission pattern and loosening potential of the fixation, the von Mises stress values, and maximum displacements of the distal radius were recorded.…”

“…(5) The two most common surgical techniques are Kirschner wire (K-wire) and volar locking plate (VP) fixations. (5,6) VP provides stronger fixation that facilitates early motion and early return to work which is still considered more invasive, time-consuming and delays wound healing (5)(6)(7)(8)(9) K-wire fixation is a well-established procedure with many advantages including minimal invasion, rapid application and lower cost of treatment. However, one disadvantage includes the fixation strength, the most concerning drawback, leading to pin loosening or migration.…”