A common treatment for long bone fractures, namely lag screw and plate fixation, still has relatively high failure rates, especially in case of oblique fracture. The best practice for lag screw fixation condition, i.e. angle, is controversial. Therefore, the aim of this study was to biomechanically evaluate the effect of screw angle conditions on the stability of fixation to determine the optimal condition using finite element (FE) analysis. The FE models of simplified long bone fracture fixation with various screw angle conditions between 0° to 60° were created for analyzing and comparing their fixation performance. The analyses were performed under lag screw fixation condition and various load conditions (compression, torsion, and bending loads). The screw which installed perpendicularly to the longitudinal axis of bone provided the best performance in terms of generating the highest interfragmentary compression and performed the best stability while loads applied
