Comparison of Spiral Versus Lateral Plate Fixations in Treatment of Multiple Humeral Fractures: A Finite Element Analysis

Abstract

Open reduction internal fixation technique has been generally accepted for treatment of complex humeral fractures. Traditional proximal humeral locking plate design (PHILOS) have been reported in clinical or biomechanical researches, while presently the spiral plate design has been introduced improved biomechanical behavior over conventional designs. In order to objectively realize the multi-directional biomechanical performances and minimally invasive surgery for humeral plate designs, a current conceptual finite element analysis has been conducted with identical cross-sectional features for humeral plates. The conceptual lateral, and spiral humeral plate models were constructed for virtual reduction and fixation to the multiple fractures of the humerus. Mechanical load cases including axial compression, counterclockwise torsion and anterior bending have been applied for confirming the multi-directional structural stability and implant safety in biomechanical perspective. Results revealed that the lateral humeral plate model showed lower equivalent (von-Mises) stress under counterclockwise torsion, while the spiral humeral plate model performed greater rigidity and lower equivalent (von-Mises) stress under other loading cases. Four models represented similar structural stiffness under bending load. Under the different mechanical load cases, the spiral humeral plate model revealed comparable results with acceptable multi-directional biomechanical behavior. The concept of spiral humeral plate design is worth considering in practical application in clinics. Implant safety and stability should be further investigated by evidences in future mechanical tests and clinical observations.