New Joint Implant Coating to Prevent Bacterial Infections
- by Jose Joaquín Belmonte Botía
Much too often artificial joints become infected after implantation and revision procedures are common. Antibiotic-enriched bone cement is often positioned within an infected joint after removing the implant and allowed to do its thing for a number of weeks before a new implant is introduced. The problem is that the bone cement is limited in its ability to kill nearby bacteria and using it requires two separate revision surgeries: explantation of the original implant and implantation of bone cement, followed by implantation of the replacement joint.
Now a team at Massachusetts General Hospital has come up with a polymer infused with an antibiotic that works better and longer, and would result in only one surgery in cases of revision. The material they used is polyethylene, the most frequently employed polymer for weight-bearing surfaces on implants. By attaching clusters of the antibiotic to the polyethylene, the investigators were able to maintain the structural integrity of the material. Bone-cement, on the other hand, does not lend itself to being infused with high concentration of antibiotics and so does not work well in too many patient cases.
The Mass General team tested the new material on animals whose joints were purposefully infected with Staphylococcus aureus bacteria, including having formations of bacterial biofilms. The researchers discovered that the new material got rid of the bacterial infection in all the cases, while controls that were treated with the antibiotic-infused bone cement were not able to get rid of their infections.