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

• Effective antibacterial efficacy against MRSA, achieved through sustained magnesium and hydrogen peroxide release. • Biocompatible and stable scaffold with optimized porosity and mechanics designed for effective bone defect repair. • Enhanced bone regeneration and osteointegration in vivo confirmed by micro-CT, histology, and immunohistochemical markers. 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 (MgO 2 )–doped calcium phosphate silicate (CSP) scaffold to address both structural and antibacterial demands. The MgO 2 –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% MgO 2 scaffold (B14M) inhibited 80.4 % of Gram-negative bacteria and 74.6 % of MRSA via Mg 2+ and H 2 O 2 release, while both B0M (no MgO 2 ) 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 MgO 2 –CSP scaffolds as a promising strategy to promote osteogenesis while combating MRSA-associated infections in RTKA.