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A new hydrogel may help people recovering from knee and hip replacement surgery. Sturti/Getty Images
  • Researchers say they are developing a hydrogen injection that can help treat infections after knee or hip replacement surgery.
  • They hope the treatment can help reduce the need for antibiotics or additional surgery following these procedures.
  • Experts say the potential hydrogel injection is a promising development, but more study is needed.

Infections that occur after a total knee or hip replacement can be dangerous and can require antibiotics and additional surgery to rectify.

In response, researchers from Shanghai Jiao Tong University School of Medicine in China say they have developed a hydrogel treatment that treats infections around prosthetics.

The gel, they say, inhibits bacterial growth and promotes tissue regrowth, potentially eliminating the need for antibiotics or follow-up surgery.

Their findings were published today in the journal APL Bioengineering.

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

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

However, the study researchers noted that problems can develop:

  • Treatment-resistant bacteria caused by the overuse of antibiotics can make eliminating the infection difficult.
  • Tissue removal and transplantation of new tissue can cause persistent damage.
  • It might be challenging to locate tissue donors.
  • There could be toxicity or immune system complications; for example, the immune system could reject the transplanted tissue.

As a solution, the researchers say they developed a black phosphorous-enhanced antibacterial injectable hydrogel that can reestablish biological barriers in soft tissue by depositing collagen fibers and promoting the growth of new blood cells.

They say the antibacterial properties helped suppress persistent the growth of bacteria, including staphylococcus aureus, a common bacterium that causes disease.

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

“Generally, acknowledged rates are between 1 to 2 percent of joint replacement surgery. Still, these numbers can vary considerably related to 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 testing showed that the gel has good stability and low toxicity to cultured cells. It also has a porous structure, can be quickly injected, and has fast self-healing properties.

“My understanding of this statement is that for this gel material when exposed to infrared light, silver ions are released into the 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 would need to be studied in a much broader way 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 infected soft tissue healing.

They hope it proves helpful in clinical settings after they conclude additional studies on the underlying mechanisms of the hydrogel.

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

These types of bacteria are complex and sometimes nearly 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 one example of a medical procedure that relies on antibiotics to fight infections.

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

“Currently, treatment typically consists of surgical tissue debridement and often removal of the prosthesis with subsequent reimplantation once the infection is controlled,” Gibson told Healthline. “Despite aggressive surgical management and focused antibiotics, therapy is frequently unsuccessful. Infectious disease consultation is required to help in selecting the appropriate antibiotics. Treatment can also drag on for weeks or months.”

This study looks at a potentially new approach for bacterial infections that happen after a joint replacement.

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

“This treatment appears novel, but it is in its infancy,” Gibson said. “It needs to be investigated in more real-world situations before being 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 infection with an injectable black phosphorus-enhanced hydrogel. The idea is very intriguing and shows promise.”

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