In vitro antibacterial and In vivo osteogenesis of 3D-printed magnesium peroxide–doped calcium phosphate silicate scaffolds for revision total knee arthroplasty

Revision total knee arthroplasty (RTKA) often encounters tibial bone defects and high infection risk, especially from methicillin-resistant Staphylococcus aureus (MRSA). Current strategies rely on bone grafts with antibiotics, but prolonged use promotes resistance. Here, we developed a 3D-printed magnesium peroxide (MgO₂)–doped calcium phosphate silicate (CSP) scaffold to address both structural and antibacterial demands. The MgO₂–CSP scaffold exhibited cancellous bone-like strength (∼7.95 MPa) and an interconnected macroporous structure conducive to cell migration and healing. In vitro, the 14 wt% MgO₂ scaffold (B14M) inhibited 80.4 % of Gram-negative bacteria and 74.6 % of MRSA via Mg²⁺ and H₂O₂ release, while both B0M (no MgO₂) and B14M promoted BMSC proliferation and osteogenic differentiation. In vivo, the B14M scaffold markedly enhanced bone regeneration in rat tibial defects, achieving a BV/TV of ∼73.09 % versus ∼29.84 % for B0M at 8 weeks. These findings highlight MgO₂–CSP scaffolds as a promising strategy to promote osteogenesis while combating MRSA-associated infections in RTKA.