A new technique may prevent infection, one of the main causes of medical implant failure, researchers suggest.

Infection is one of the main causes of implant failure, resulting in prolonged pain and medical expense. “The biggest benefit of this work is to keep the infection from ever starting,” notes study author, Eric Wickstrom, professor of biochemistry and molecular biology at Jefferson Medical College (JMC).

Active antibiotics can be connected to the titanium surface, ready to kill any bacteria that try to attach themselves to the implant device, results indicate. “Our technique puts a bed of antibiotic nails on the surface of the implant, Wickstrom suggests. The first time a bacterium lands on those nails, it dies.”

Infection Risk Extends Beyond Post-Op Period

Currently, when an orthopedic device is implanted, physicians may apply an antibiotic-loaded adhesive to the site to prevent infection. “The hope is that the drugs in the glue will protect the implant and strengthen its attachment to the bone, but that doesn’t always work,” explains study co-author Noreen Hickok, associate professor of orthopedic surgery at JMC.

Infections due to contamination during surgery are infrequent, Hickok notes. However, bacteria can spread to the implants later from other infections anywhere in the body, causing significant pain.

When infection occurs, physicians replace the implant and administer an aggressive round of antibiotics. The procedure can cost tens of thousands of dollars.

Improved Implants May Work Better, Last Longer

“When an infected implant is taken out, it’s usually covered with a slimy layer of bacteria," Hickok explains. "We’re moving from just having a bacteria-killing surface to having one that prevents infection while promoting better bone-implant interactions. The idea is to have the implant last for many more years and avoid infection.”

The technique developed for titanium can also be used for plastic devices such as bladder catheters and pacemakers, researchers suggest. “Every implant you can think of is a magnet for bacteria,” according to Wickstrom.

Promising Results

The new study provides a critical first step toward rendering all medical implants bacteria-resistant.

Researchers focused on fastening the antibiotic vancomycin to titanium powder in the study. They used microscopy to confirm the vancomycin had attached to the titanium, and then added bacteria to the powder to see if the antibiotic would kill it.

Vancomycin killed the initial bacteria and continued to aggressively curtail subsequent re-infections, the team reports.

The study authors reported their results in the September 23, 2005, issue of the journal Chemistry and Biology.