Biomechanical Evaluation of PEEK and PLA Composite Femoral Implants for Stress Shielding Reduction: A Finite Element Simulation Study

Background: Total hip arthroplasty (THA) is a widely adopted surgical intervention for restoring mobility and reducing pain in patients with severe hip joint conditions, such as osteoporosis. However, traditional titanium implants often lead to stress shielding and subsequent bone resorption due to the mismatch in stiffness between the implant and bone. Objectives: This study computationally investigates the biomechanical performance of femoral implants made from composite materials, specifically polyether-ether-ketone (PEEK) and polylactic acid (PLA) reinforced with hydroxyapatite (HA), compared to conventional titanium stems. Methods: Using finite element (FE) modeling, physiological loading during walking was simulated, and the strain energy density (SED) was analyzed to assess stress distribution and the potential for stress shielding across different Gruen zones. Results: The results indicate that both the PEEK and PLA composites exhibited more physiological load transfer, particularly in Gruen zones 1 and 7, reducing stress shielding and supporting bone preservation. Conclusions: These findings suggest that PEEK and PLA composites may offer improved implant stability and bone integration. Despite highlighting the promise of biomimetic materials in orthopedics, this study is limited to computational analysis and requires experimental validation. It emphasizes the need for further investigation using patient-specific geometries and a variety of loading scenarios to confirm these benefits and optimize femoral implant design.