The interface between the metal and the bone is always at risk of infection when patients receive titanium-alloy artificial hip joints,media New Atlas reported. However, a new implant coating process is designed to significantly reduce this risk. The technology was developed by the Fraunhofer Institute for Manufacturing Technology and Advanced Materials in Cooperation with the Faculty of Medicine of the University of Berlin. It is part of the larger AntiSelectInfekt project.
The first step for the researchers was to finely structure the surface of existing titanium hip joints using lasers. Doing so fills the metal surface with micro-holes, each shaped like a small thin-necked bottle — meaning they are wider at the bottom than at the top. Next, a technique called physical vapor deposition is used to coat a thin layer of silver on the metal. Silver with antibacterial properties is applied to the inner wall of each hole, but it is not actually filled. Finally, just before implantation, the titanium hip joint was immersed in an antibiotic solution. This liquid is drawn into the pores.
Once the hip is implanted, antibiotics (tailored to each patient’s specific needs) flow from the pores into the surrounding tissue. This helps prevent any infection immediately after surgery. However, silver releases ions that kill bacteria over the next few weeks, providing protection against infection throughout the healing phase.
In addition, as the surface of the implant becomes more textured and porous, it can better blend with adjacent bones. In fact, bone cells actually grow in pores, helping to fix implants to the bone over time.
Preclinical trials have shown that the coating process is effective in preventing infection. It can also be applied to other types of titanium joints, such as shoulders and knees. Other ways to kill bacteria at such implant sites in recent years have included antibiotic beads and graphene tablets released over time.