Tissue reaction to bone-anchored percutaneous implants in rabbits.

It has been demonstrated that direct attachment to bony skeletal tissues favors the longevity of percutaneous devices (PDs). This study is focused on improvement of the success rates by using a two-stage implantation technique. For this purpose, cylindrical-shaped PDs were inserted into the tibia of rabbits. The enossal part of the implants was made of Ti6Al4V and was coated with a layer hydroxyapatite (HA). The percutaneous part was made of dense HA. In a first surgical session, the enossal part of the implants was inserted. In a second implantation session, about 3 months later, the percutaneous part was fixed into the enossal part. The implants were left in situ for 5 months after the second session. Clinical and histological investigations were performed. The results confirmed the previous finding--that bone anchoring is effective in the maintenance of a permanent percutaneous passage. On the other hand, it could not be proven that a two-stage implantation procedure improves the success rate of one-stage bone-anchored PDs.