The influence of design factors on the mechanical properties of biodegradable composite plates: A finite element analysis

OBJECTIVES: This study aims to investigate the influence of implant design factors on mechanical behavior and to identify lower-profile biocomposite plate configurations with mechanical responses approaching those of a titanium reference construct under selected loading conditions. MATERIALS AND METHODS: In this computational finite element study, three-dimensional implant models were developed, and material properties of polyamide-6/nano-hydroxyapatite and titanium alloy (Ti6Al4V) were assigned. Seven composite plate types were modeled: flat (thicknesses 8, 9, and 10 mm), bellied, curved, enhanced, and hybrid plate. All constructs were mounted on a cylindrical synthetic femoral diaphyseal surrogate and fixed with six screws. Finite element analysis was conducted using ANSYS Mechanical 2022 R2 under axial compression (800 N), distraction (300 N), and torsion (10 Nm). Mechanical responses including maximum deformation, von Mises stress, and strain distribution in bone, plate, and screws were evaluated. Results were evaluated descriptively and comparatively across implant configurations and loading conditions. RESULTS: The titanium construct generally demonstrated the lowest deformation under torsional loading and the lowest plate strain response, whereas selected composite geometries approached or exceeded titanium-like deformation performance under specific loading modes. The hybrid plate showed the lowest deformation under compression, while the thick flat plate provided the lowest deformation among composites under distraction and torsion. The bellied design showed lower torsion-induced deformation and lower plate stress than most other lower-profile composite configurations. The enhanced plate exhibited the lowest plate strain among the composite models under compression and distraction but may pose challenges for soft tissue coverage due to its complex geometry. CONCLUSION: Optimizing plate geometry can substantially modify the mechanical behavior of biodegradable composite constructs. Hybrid and enhanced designs demonstrated load-mode specific mechanical responses that may inform future biodegradable plate optimization, particularly with further material refinement and experimental validation.