Titania nanotube morphologies for osseointegration via models of in vitro osseointegrative potential and in vivo intramedullary fixation

As total joint replacements increase annually, new strategies to attain solid bone-implant fixation are needed to increase implant survivorship. This study evaluated two morphologies of titania nanotubes (TiNT) in in vitro experiments and an in vivo rodent model of intramedullary fixation, to simulate joint arthroplasty conditions. TiNT surfaces were prepared via an electrochemical etching process, resulting in two different TiNT morphologies, an aligned structure with nanotubes in parallel and a trabecular bone-like structure. in vitro data showed bone marrow cell differentiation into osteoblasts as well as osteoblastic phenotypic behavior through 21 days. In vivo, both TiNT morphologies generated greater bone formation and bone-implant contact than control at 12 weeks, as indicated by mu CT analyses and histology, respectively. TiNT groups also exhibited greater strength of fixation compared to controls, when subjected to wire pull-out testing. TiNT may be a promising surface modification for promoting osseointegration.