Biomechanical evaluation of the osseointegration of biologically coated open-cell titanium implants

The aim of this paper is to compare the osseointegration of open-cell titanium implants with or without the application of a biological CaTiO ₃ reaction layer. Cellular implants on the basis of Ti6Al7Nb were precision cast and the brittle a-case was removed by means of a pickling process. Coated and uncoated specimens were then implanted into the distal femural metaphysis of sheep. After six months the sheep were euthanized in order to extract samples from the femural metaphysis. Half of the samples were used for histomorphological investigations and the rest of the samples were prepared for biomechanical testing. Prior to push-out testing the samples were aligned in the loading direction with the help of X-ray analysis. Compared to control samples the level of push-out loads increased by a factor of about 3-4 during the period of exposure to the living organism but no significant difference was measured between coated and uncoated specimens. SEM investigations revealed high amounts of cancellous bone formation inside the implants particularly in the main trabecular direction of the surrounding bone in both cases and mineralized bone adhesion at the pickled surfaces of the implants proving the excellent biocompatibility of both coated and uncoated implants.