The END of Implant Associated Bone Infections?

It is big news when antibiotic-containing microspheres prevented infections in 100% of grossly contaminated wounds. Researchers at The University of Texas Health Science Center at Houston (UTHealth) and collaborators at Rice University and Shriners Hospital for Children-Houston have come up with an application that may wipe-out implant-associated bone infections all together.

The lead investigator is Catherine Ambrose, Ph.D, an associate professor in the Department of Orthopaedic Surgery at the UTHealth Medical School. In this clinical study, the third she has conducted, the researchers found that porous metal implants that were coated with the microspheres prevented infection in 100% of the 11 specimens studied. In the tissue and bone surrounding the implants that were not coated with the antibiotic delivery system, infection occurred at a 64% rate.

Total joint surgeries have a low infection rate—of from 1 to 3%—but when bone infection does set in, it can be devastating for the patient. Terry Clyburn, M.D., professor of orthopaedics and director of Total Joint Services at the UTHealth Medical School, said antibiotic-containing microspheres could serve to prevent these rare but devastating and often hard-to-treat infections.

“When these infections occur, it can be a huge setback for patients, ” Clyburn said. “Sometimes the implant has to be removed entirely to treat a painful infection and they require multiple surgeries. If these microspheres could prevent those infections from happening in the first place, this would be a significant advancement.”

In the Universities’ press release Ambrose was quoted as saying that the microspheres would appear to overcome a number of obstacles health care teams currently face when treating osteomyelitis—bone infection. The microspheres could be administered directly at the surgical site, eliminating the need for systemic antibiotics that impact the entire body. Made of biodegradable polymers, the antibiotics are gradually released over a period of weeks and eventually the microspheres dissolve, allowing time to prevent or treat an infection while reducing the likelihood of additional surgeries. Ambrose noted that, “because the antibiotic delivery system is microscopic in size, it does not appear to interfere with the healing after a total joint replacement.”

The findings, the third in a series of research studies that Ambrose and her collaborators have published in the Journal of Bone and Joint Surgery, demonstrate the potential of antibiotic microspheres. “The first two studies confirmed in animal models that the microspheres were safe and effective in treating bone infection associated with orthopaedic implants.” Ambrose believes that the microspheres may also have applications in the treatment of open fractures in trauma patients.