Ion Implantation as Surface Treatment for Osseointegration of Musculoskeletal Implants: From the Lab to the Clinic

Abstract

AbstractA key process in a successful treatment of patients with a great variety of musculoskeletal implants requires a fast, reliable and consistent osseointegration. Among the parameters that affect this process, it is widely admitted that implant surface topography, surface energy and composition play an important role.Different surface modification techniques to improve osseointegration have been proposed and tested to date, but most focus on microscale features, and few control surface modifications at nanoscale. On the other hand, ion implantation modifies the outermost surface properties in relation to the nanotopography, chemical and physical characteristics at nanoscale. The meta-stable surface that results from the treatment, affects the adsorption of bio-molecules in the very first stages of the implant placement, and thus the signaling pathway that promotes the differentiation and apposition of osteoblast cells.This study aimed at assessing the performance, in terms of osseointegration levels and speed, of ion implanted titanium made implants. The study included several in vitro and in vivo tests. The latter, comprised different insertion periods and both experimental and commercial implants as comparative surfaces. The final stage of the study included clinical trials in human patients.In each and every case, bone integration improvement of tested materials/implants was achieved for the CO ion implanted samples. Furthermore, contact osteogenesis was observed in the ion implanted samples, unlike the Ti control samples, where only distance osteogenesis occurred, being this potentially one of the reasons for their faster healing and osseointegration process.Finally, the use of ion implantation as a surface modification tool that allows for evaluating the effects of nanotopography and composition changes independently is presented.