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

Journal of Orthopaedic Translation, vol. 59, pp. 101132

Abstract

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.

Authors 11

1. Alexander Kopp corresponding
   Affiliation as printed

   Medical Magnesium, GmbH, Philipsstr. 8, Aachen, 52068, Germany

   Meotec GmbH, Philipsstraße 8, Aachen, 52068, Germany

2. Henri Kreiker

   Humboldt-Universität zu Berlin · Freie Universität Berlin · Charité – Universitätsmedizin Berlin

   Affiliation as printed

   Charité - Universitätsmedizin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Department of Oral and Maxillofacial Surgery, Augustenburger Platz 1, Berlin, 13353, Germany

3. Heilwig Fischer
   Affiliation as printed

   Department of Anesthesiology and Intensive Care Medicine, Havelland Kliniken GmbH, Ketziner St. 19, Nauen, 14641, Germany

4. Ana Prates Soares

   Humboldt-Universität zu Berlin · Berlin Institute of Health at Charité - Universitätsmedizin Berlin · Freie Universität Berlin · Charité – Universitätsmedizin Berlin

   Affiliation as printed

   Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Julius Wolff Institute, Augustenburger Platz 1, Berlin, 13353, Germany

   Charité - Universitätsmedizin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Department of Oral and Maxillofacial Surgery, Augustenburger Platz 1, Berlin, 13353, Germany

5. Katharina Schmidt‐Bleek

   Berlin Institute of Health at Charité - Universitätsmedizin Berlin

   Affiliation as printed

   Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Julius Wolff Institute, Augustenburger Platz 1, Berlin, 13353, Germany

6. Georg N. Duda

   Berlin Institute of Health at Charité - Universitätsmedizin Berlin

   Affiliation as printed

   Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Julius Wolff Institute, Augustenburger Platz 1, Berlin, 13353, Germany

7. Henning Hanken

   University Medical Center Hamburg-Eppendorf

   Affiliation as printed

   University Medical Center Hamburg-Eppendorf, Department of Oral and Maxillofacial Surgery, Martinistraße 52, Hamburg, 20246, Germany

8. Nadja Kröger Aachen Institute for Laboratory Animal Science and Experimental Surgery Medical Faculty

   RWTH Aachen University

   Affiliation as printed

   Institute for Laboratory Animal Science and Experimental Surgery, Medical Faculty, RWTH Aachen International University, Pauwelsstraße 30, Aachen, 52074, Germany

9. Max Heiland

   Humboldt-Universität zu Berlin · Freie Universität Berlin · Charité – Universitätsmedizin Berlin

   Affiliation as printed

   Charité - Universitätsmedizin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Department of Oral and Maxillofacial Surgery, Augustenburger Platz 1, Berlin, 13353, Germany

10. Ralf Smeets

    University Medical Center Hamburg-Eppendorf

    Affiliation as printed

    University Medical Center Hamburg-Eppendorf, Department of Oral and Maxillofacial Surgery, Division of "Regenerative Orofacial Medicine", Martinistraße 52, Hamburg, 20246, Germany

    University Medical Center Hamburg-Eppendorf, Department of Oral and Maxillofacial Surgery, Martinistraße 52, Hamburg, 20246, Germany

11. Carsten Rendenbach

    Humboldt-Universität zu Berlin · Freie Universität Berlin · Charité – Universitätsmedizin Berlin

    Affiliation as printed

    Charité - Universitätsmedizin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Department of Oral and Maxillofacial Surgery, Augustenburger Platz 1, Berlin, 13353, Germany