Hydrogel Injection May Help Reduce Infections

After knee and hip replacement surgery, bacteria can adhere to the surface of the artificial joint, causing infection.

Typically, this type of infection is treated with antibiotics and, if necessary, additional surgery to remove infected tissue and graft new tissue.

However, the study researchers noted that problems can develop:

• Treatment-resistant bacteria caused by overuse of antibiotics can make it difficult to clear the infection.
• Tissue removal and transplantation of new tissue can cause lasting damage.
• Locating tissue donors can be difficult.
• There could be toxicity or immune system complications; for example, the immune system could reject the grafted tissue.

As a solution, the researchers say they have developed an antibacterial injectable hydrogel enriched with black phosphorus that can restore biological barriers in soft tissues by depositing collagen fibers and promoting the growth of new blood cells.

They say the antibacterial properties helped suppress the persistent growth of bacteria, including Staphylococcus aureusa common bacteria that causes disease.

“Periprosthetic joint infection after knee or hip replacement surgery is a rare but serious complication of this surgery,” said Dr. Jeffrey Zarineorthopedic surgeon at the Cedars-Sinai Kerlan-Jobe Institute in Los Angeles.

“In general, the recognized rates are between 1 and 2% of joint replacement surgeries. Yet these numbers can vary widely depending on patient comorbidities, such as diabetes, obesity, smoking, and surgical factors, such as complexity and length of surgery,” Zarin told Healthline.

The researchers reported that laboratory tests showed that the gel has good stability and low toxicity to cultured cells. It also has a porous structure, can be injected quickly and has rapid self-healing properties.

“My understanding of this statement is that for this gel material when exposed to infrared light, silver ions are released into local tissues,” Zarin said. “Silver ions have been shown to have antibacterial properties. Therefore, the local release of these ions would potentially have an increased antibacterial effect. This should be studied much more broadly to determine if it is clinically relevant and tested to minimize the risk of toxicity and side effects.

According to the researchers, the new gel provides a safe, minimally invasive and feasible antibacterial strategy for healing infected soft tissue.

They hope it will prove useful in a clinical setting after concluding further studies on the underlying mechanisms of the hydrogel.

Treatment-resistant bacteria occur when bacteria develop the ability to resist drugs intended to kill them, according to the Centers for Disaster Control and Prevention (CDC).

These types of bacteria are complex and sometimes almost impossible to treat.

The CDC estimates that more than 2.8 million treatment-resistant infections occur in the United States each year, with more than 35,000 deaths attributed to them.

Joint replacement is an example of a medical procedure that relies on antibiotics to fight infections.

“Antibiotic-resistant bacteria are becoming a bigger problem in the treatment of infected joint replacements, said Dr. Timothy Gibsonorthopedic surgeon and medical director of MemorialCare Joint Replacement Center at Orange Coast Medical Center in California.

“Currently, treatment typically consists of surgical debridement of tissue and often removal of the prosthesis followed by subsequent reimplantation once the infection is under control,” Gibson told Healthline. “Despite aggressive surgical management and targeted antibiotics, treatment often fails. An infectious disease consultation is needed to help choose the appropriate antibiotics. Treatment can also last for weeks or months.

This study examines a potentially novel approach to bacterial infections that occur after joint replacement surgery.

According to a Press release, the researchers believe that the hydrogel provides a safe and feasible strategy for treating soft tissue infections and that it solves the problems of stubborn infections with a minimally invasive treatment. They hope to continue studying the underlying mechanisms of the hydrogel and testing its safety and efficacy in humans.

“This treatment seems new, but it’s in its infancy,” Gibson said. “It needs to be studied in more real-life situations before it is implemented in a clinical setting. I would not recommend this new treatment at this time. This study proposes an interesting and unique method to treat and potentially control the infection with an injectable hydrogel enriched with black phosphorus. The idea is very intriguing and promising.

“The authors are to be commended for their innovative approach to this difficult problem,” Gibson added. “If further studies show patient benefit and appropriate safety, this could be a very useful tool to use in our treatment of these complex infections.”