Femoral neck fractures, comprising 8–10% of all bodily fractures in the elderly, often necessitate alternatives to extensive surgical interventions. Despite limited research, external fixators are considered promising. This study evaluates the design and durability of a novel modular axial fixator (MAF) for stable and unstable proximal femoral fractures, using numerical method-based engineering analysis. Employing patient-specific CT scan data, three-dimensional (3D) solid modeling, and finite element analysis (FEA), the MAF-bone fixation is examined in eight simulation scenarios under static loading conditions. FEA results show a peak femur head displacement of 7.429 mm in FEA 001, with Schanz screw no. 2 reaching the maximum equivalent stress at 431.060 MPa in FEA-006. Notably, the 7.429-mm displacement improves stability compared to previous studies, yet interfragmentary movement surpasses the 100–200 μm reference range for primary fracture healing, posing challenges to direct healing despite enhanced stability. This study validates the durability of the innovative MAF for femoral neck fractures through engineering simulations. It contributes to understanding MAF durability issues, with implications for improving medical implant design in the industry. Simulation results offer opportunities for optimizing structure and production, enhancing the MAF's design, and ultimately benefiting medical implant manufacturing.