Biomechanical evaluation of the modified double-plating fixation for the distal radius fracture.

BACKGROUND

Distal radius fracture is among the most common type of skeletal injuries. To conquer the surgical and biomechanical complications of the most-frequent used double-plating operation for this fracture, modified double-plating technique was proposed in this study. The aim of this study was to investigate the biomechanical interactions of double-plating, modified double-plating and traditional single plating fixations coupled with various load conditions using nonlinear finite element analysis.

METHODS

A three-dimensional finite element distal radius fracture model with three fixation methods (double-plating, modified double-plating and single) was generated based on computer tomography data. After model verification and validation, frictional (contact) elements were used to simulate the interface condition between the fixation plates and the bony surface. The rigidity, stress values and displacements at the radius end were observed under axial, bending and torsion load conditions.

FINDINGS

The simulated results showed that the modified double-plating model demonstrated the highest rigidity and the least displacement among the three techniques in bending, but not in axial compression (similar results across the three) and torsion (modified double-plating technique possessed lowest rigidity). The maximum von Mises stress for bone was lower in modified double-plating model as well. These results indicated that modified double-plating technique demonstrated a better structural strength against bending with the least potential of fracture fragments and screw loosening.

INTERPRETATION

Although a lower torsional rigidity, modified double-plating technique was a better choice in distal radius fracture fixation since the bending force, which has the potential to separate the fracture ends, is more detrimental in hindering fracture healing.