Long-term evaluation of plasma electrolytic oxidation (PEO) surface-modified WE43MEO magnesium alloy screws and plates reveals safe and controlled degradation in a 18-month minipig model

Background Magnesium-based implants are increasingly investigated as bioabsorbable materials for temporary osteosynthesis applications due to their favorable biocompatibility and bone-like elastic modulus. However, controlling the degradation rate remains a critical barrier to clinical translation, as rapid corrosion can compromise mechanical integrity and lead to adverse effects, such as gas formation. Methods PEO-modified WE43MEO (WE43-PEO) and non-modified WE43MEO screws and plates were implanted in the humerus and femur of Göttinger minipigs in a non-fracture model and assessed after 18 months. Explants were analyzed using micro-computed tomography and non-decalcified histology with histomorphometric quantification of residual implant structure and peri-implant bone response. Results No significant differences in cortical implant volume were observed. However, PEO modified implants were surrounded by significantly higher volumes of lamellar bone, suggesting reduced remodeling and improved bone integration. Non-modified WE43MEO implants underwent complete degradation, while PEO modified implants showed partial resorption with preserved structure, indicating effective degradation control. Both implant types remained integrated without long-term complications. Conclusion PEO surface modification of WE43 magnesium implants supports predictable, biocompatible long-term degradation and promotes favorable bone quality without late complications, underscoring the potential of surface-engineered magnesium fixation devices for load-bearing applications. The translational potential of this article PEO-modified WE43MEO osteosynthesis systems may offer clinically relevant, bioabsorbable fixation with controlled degradation and improved long-term bone integration, potentially reducing implant-related complications and the need for secondary removal procedures in orthopaedic and craniomaxillofacial surgery.