Researchers from Massachusetts General Hospital have developed an antibiotic-eluting polymer that could be used to treat infections in orthopedic implants, according to a report published in Nature Biomedical Engineering.
Traditionally, treating a prosthetic joint infection involves removing an implant and replacing it with a temporary spacer made from antibiotic-releasing bone cement for at least six weeks. Then, a second surgery is needed to give the patient a new prosthesis.
“Currently, most infections involving total joint replacement prostheses require a two-stage surgery, in which the patient’s daily activities are largely compromised for four to six months,” co-author Orhun Muratoglu said in prepared remarks. “Our finding that polyethylene, the most commonly used weight-bearing surface in total joint surgery, can be made to safely and effectively release antibiotics implies that fully weight-bearing implants made with this material could be used to treat infection in a single procedure, reducing both the inconvenience and the risk of complications for patients.”
Drug-eluting bone cement is limited in its ability to release antibiotics at an effective dose, according to the researchers, and upping the antibiotic content lowers the material’s durability.
The team from MGH designed and developed a polymer that could be incorporated directly into an orthopedic implant.
Based on modeling, the team developed a material with antibiotic clusters that were irregularly shaped, allowing them to release effective doses over time without reducing the material’s durability. The researchers tested implants made from this polymer in animal models of prosthetic joint infection and observed that the drug-eluting polymer successfully eliminated two different models of infection.
In contrast, the team reported that implanting a drug-releasing bone cement spacer was not effective.
“We used two separate infection models because, when patients present with prosthetic joint infection symptoms, it is not clear what proportion of bacteria may be in a biofilm and what are free floating in solution,” Muratoglu said. “The ability of our devices to eradicate all bacteria in the joints in both models strongly suggests they would be successful against both types of periprosthetic infection.”
The team is reportedly working with the FDA to pursue regulatory approval for the material.