Surface topography of silicon nitride affects antimicrobial and osseointegrative properties of tibial implants in a murine model

While silicon nitride (Si3 N4 ) is an antimicrobial and osseointegrative orthopaedic biomaterial, the contribution of surface topography to these properties is unknown. Using a methicillin-resistant strain of Staphylococcus aureus (MRSA), this study evaluated Si3 N4 implants in vitro utilizing scanning electron microscopy (SEM) with colony forming unit (CFU) assays, and later in an established in vivo murine tibia model of implant-associated osteomyelitis. In vitro, the "as-fired" Si3 N4 implants displayed significant reductions in adherent bacteria versus machined Si3 N4 (2.6 × 104 vs. 8.7 × 104 CFU, respectively; p