Bone ongrowth and mechanical fixation of implants in cortical and cancellous bone

Abstract Background What is the right surface for an implant to achieve biological fixation? Surface technologies can play important roles in encouraging interactions between the implant surface and the host bone to achieve osseointegration. Pre-clinical animal models provide important insight into in-vivo performance related to bone ongrowth and implant fixation. Methods A large animal model was used to compared the in vivo response of HA and plasma sprayed titanium coatings in a well reported adult ovine model to evaluate bone ongrowth in terms of mechanical properties in cortical sites, histology and histomorphometry in cortical and cancellous sites at 4 and 12 weeks. Results Titanium plasma sprayed surfaces outperformed the HA coated samples in push-out testing in cortical sites while both surfaces supported new bone ongrowth and remodeling in cortical and cancellous sites. Conclusions While both HA and Ti plasma provided an osteoconductive surface for bone ongrowth, the Ti plasma provided a more robust bone-implant interface that ideally would be required for load transfer and implant stability in the longer term.