Intraoperative loading of calcium phosphate-coated implants with gentamicin prevents experimental Staphylococcus aureus infection in vivo

Orthopedic device-related infection (ODRI) is a potentially devastating complication arising from the colonization of the device with bacteria, such as Staphylococcus aureus . The aim of this study was to determine if intraoperative loading of a clinically approved calcium phosphate (CaP) coating with gentamicin can protect from ODRI in vivo . First, CaP-coated titanium aluminium niobium (TAN) discs were used to investigate the adsorption and release kinetics of gentamicin in vitro . Gentamicin loading and subsequent release from the coating were both rapid, with maximum loading occurring following one second of immersion, and >95% gentamicin released within 15 min in aqueous solution, respectively. Second, efficacy of the gentamicin-loaded CaP coating for preventing ODRI in vivo was investigated using a CaP-coated unicortical TAN screw implanted into the proximal tibia of skeletally mature female Wistar rats, following inoculation of the implant site with S . aureus . Gentamicin-loading prevented ODRI in 7/8 animals, whereas 9/9 of the non-gentamicin treated animals were infected after 7 days. In conclusion, gentamicin can be rapidly and simply loaded onto, and released from, CaP-based implant coatings, and this is an effective strategy for preventing peri-operative S . aureus -induced ODRI in vivo .