Autologous osteoblasts enhance osseointegration of porous titanium implants

The goal of this study was to assess the osseointegration of porous titanium implants by means of coating with autologous osteoblasts. Titanium implants (8 x 5 x 4 mm) having drill channels with diameters of 400, 500, and 600 microm were coated with autologous osteoblasts obtained from spongiosa chips. The implants were inserted into the distal femora of 17 adult Chinchilla Bastard rabbits (group I). Uncoated implants were inserted as controls in the contralateral femur (group II). The animals were sacrificed after 5, 11, and 42 days. Intravital fluorochrome labeling and microradiography were used for the assessment of bone ingrowth into the titanium channels. In both groups, no bone tissue was formed in the channels up to day 5. On day 11, group I exhibited significantly more (p<0.05) bone tissue (19.8+/-14.0% vs. 5.8+/-9.1%) with greater bone-implant contact (13.3+/-15.1% vs. 5.7+/-5.3%, p<0.05) at the channel mouths than group II. Bone tissue was formed mainly between day 15 and 30 in group I, in group II between day 25 and 40. Six weeks after implantation, bone tissue filled on an average 68.8+/-15.1% of the mouths of the drill channels in implants in group I, the filling for group II was 49.8+/-18.1% (p<0.05). The average bone-implant contact at the channel mouths after six weeks was 56.5+/-13.5% in group I, 40.2+/-21.9% in group II (p<0.05). 600-microm channels showed at this time point the best osseous integration (p<0.05). Coating with autologous osteoblasts accelerates and enhances the osseointegration of titanium implants and could be a successful biotechnology for future clinical applications.