Bone response to implant surface morphology

This study was designed to measure implant osseointegration using different surface treatments. Bilateral distal intramedullary implantation of titanium cylinders 25 mm x 5 mm was performed in 60 rabbits. The 3 surfaces tested were fiber mesh, mean pore size 400 microns; grit-blasted, mean surface roughness 6 microns; and acid-etched, mean surface roughness 18 microns. Scanning electron microscopy was used to measure the percentage of the surface of each implant in contact with bone at 2, 6, and 12 weeks postimplantation. Mechanical pull-out testing of the bone-implant interface was performed at 12 weeks. Overall, acid-etched surfaces demonstrated greater mean osseointegration than fiber mesh surfaces. All 3 surfaces demonstrated similar interface strengths. Acid etching has potential as a means of enhancing bony apposition in cementless fixation.