Comparison with the osteoconductivity and bone-bonding ability of the iodine supported titanium, titanium with porous oxide layer and the titanium alloy in the rabbit model.

Abstract

One of the serious postoperative complications associated with joint replacement is bacterial infection. In our recent investigations, iodine supported titanium implants demonstrated antibacterial activity in both invitro and invivo studies. The surfaces of the implants have porous anodic oxide layer with the antiseptic properties of iodine. According to the literature the titanium with porous anodic oxide have good osteoconductivity. But it is not clear whether the properties of iodine influence bone bonding of implants. The aim of this study is to evaluate the influence of the properties of iodine and porous anodic oxide layer in the bone bonding ability of titanium implants. Titanium rods were implanted in intramedullary rabbit femur models, in regard to the cementless hip stem. The implant rods were 5mm in diameter and 25mm in length. Three types of titanium rods were implanted.One was untreated titanium (control group (CL)), another was titanium with oxide layer without iodine (oxide layer group (OL)), and the other was Iodine treated Titanium (iodine group (ID)). The rods were inserted into the distal femur. We assessed the bonding strength by a measuring pull-out test at 4, 8, and 12 weeks after implantation. The bone-implant interfaces were evaluated at 4 weeks after implantation. Pull-out test results of the ID implants were 202, 355, and 344N, and those of the OL implants were 220, 310, 329N at 4, 8, and 12 weeks, significantly higher than those of the CL implants (102, 216, and 227N). But there were no significant difference in ID implants and OL implants. Histological examination revealed that new bone formed on the surface of each types of implants, but significantly more bone made direct contact with the surfaces of the ID implants and OL implants. This research showed that new type of coating, iodine coated titanium has low toxicity and good osteoconductivity.