Biomechanical performance evaluation of a modified proximal humerus locking plate for distal humerus shaft fracture using finite element analysis.

The extra-articular distal humerus plate (EADHP) has been widely used for surgical treatment of distal humerus shaft fracture (DHSF). However, the surgical approach, fixation methods, and implant positions of the EADHP remain controversial owing to iatrogenic radial nerve injury and complaints such as skin irritation related to the plate. Anterior plating with a modified (upside-down application) proximal humerus locking plate (PHILOS) has been proposed as an alternative, However, research on its biomechanical performance remain insufficient and were mostly based on retrospective studies. This study quantitatively compared and evaluated the biomechanical performance between posterior plating with the EADHP and anterior plating with a modified PHILOS using finite element analysis (FEA). The FEA simulation results that both the EADHP and PHILOS had adequate biomechanical performance and stability under axial, bending, and varus force load conditions. The PHILOS has a fixed stability comparable to that of the EADHP, and fixation was achieved using only four locking screws within a fixed range of 30 mm just above the olecranon fossa. The results show that the PHILOS could be an option for the fixation of a DHSF when considering the dissection range and complaints (e.g. skin irritation) associated with the EADHP.