Objective: To compare the biomechanical performance of titanium alloy (Titanium-Aluminum-Vanadium Alloy, Ti-6Al-4V), magnesium alloy (Magnesium-Yttrium-Rare Earth-Zirconium, MgYREZr), and polylactide (PLA) cortical screws in the fixation of Fulkerson tibial tubercle osteotomy (TTO) using finite element analysis (FEA).
Materials and
Methods: A three-dimensional tibial model was created from computed tomography data of a 20-year-old male patient and simulated with a standardized Fulkerson osteotomy fixed using two bicortical screws. The screws were modeled using three different biomaterials. FEA simulations were performed under two loading conditions: 390 N (physiological gait) and 1654 N (worst-case scenario). Stress distribution (von Mises) and displacement were recorded for the osteotomy construct and screws.

Results: Under 390 N loading, Ti-6Al-4V screws demonstrated the highest mechanical resistance (max. stress: 123,830 MPa; displacement: 0.084 mm), followed by MgYREZr (95,172 MPa; 0.098 mm) and PLA (81,939 MPa; 0.219 mm). Under 1654 N loading, Ti-6Al-4V screws again showed superior performance (669,880 MPa; 0.333 mm), whereas MgYREZr (745,470 MPa; 0.407 mm) and PLA (339,720 MPa; 0.882 mm) showed increased stress and deformation, with PLA screws exhibiting the least mechanical stability.

Conclusion: Titanium screws demonstrated the highest mechanical reliability across both loading conditions, supporting their continued use in TTO, particularly in high-demand clinical scenarios. Although biodegradable materials, such as MgYREZr and PLA, offer theoretical advantages by eliminating the need for implant removal, their biomechanical performance remains inferior to titanium screws.