General Assembly, Prevention, Operating Room - Surgical Technique: Proceedings of International Consensus on Orthopedic Infections

Current Strategies in Developing Antibacterial Surfaces for Joint Arthroplasty Implant Applications

Prosthetic joint infections (PJIs) remain a significant challenge, occurring in 1% to 2% of joint arthroplasties and potentially leading to a 20% to 30% mortality rate within 5 years. The primary pathogens responsible for PJIs include Staphylococcus aureus, coagulase-negative staphylococci, and Gram-negative bacteria, typically treated with intravenous antibiotic drugs. However, this conventional approach fails to effectively eradicate biofilms or the microbial burden in affected tissues. As a result, innovative strategies are being explored to enhance the efficacy of infection prevention through the development of antibacterial-coated implants. These coatings are required to demonstrate broad-spectrum antimicrobial activity, minimal local and systemic toxicity, favorable cost-effectiveness, and support for bone healing. In the present review, the analysis of various methodologies for developing antibacterial coatings was performed, emphasizing studies that conducted in vivo tests to advance potential clinical applications. A diversity of techniques employed for the development of coatings incorporating antimicrobial agents highlights promising avenues for reducing infection-related surgical failures.

Bacterial reservoir in deeper skin is a potential source for surgical site and biomaterial-associated infections

BACKGROUND

The origin of surgical site and biomaterial-associated infection is still elusive. Micro-organisms contaminating the wound may come from the air in the operating theatre, the surgical team or the skin of the patient. The skin of patients is disinfected prior to surgery, but bacteria deeper in the skin (e.g. in sweat glands or sebaceous glands) may not be reached.

METHODS

A preliminary cohort study was performed to study the origin of surgical site and biomaterial-associated infection between May 2020 and February 2021. In order to investigate whether cutaneous microbiota colonize the wound when released from the skin upon cutting, aerobic and anaerobic bacteria were isolated, quantified and identified from the skin of 99 patients undergoing trauma surgery, before and after skin disinfection, from knife blades and from the wound directly after the first cut.

RESULTS

Ninety-nine percent of the patients were culture-positive before disinfection with chlorhexidine. Of these, 40% were still culture-positive after disinfection. Of these, 54% had a positive culture of the wound after cutting the skin. Twenty percent of the patients with a negative culture after disinfection had a positive wound culture after cutting the skin. Staphylococcus epidermidis and Cutibacterium acnes were the most commonly cultured bacterial species. In 9% of cases, more than 100 bacterial colonies were cultured from the wound; this may cause biomaterial-associated infection.

CONCLUSION

Bacteria residing in the skin and not eradicated by disinfection may enter the surgical wound upon cutting, resulting in contamination which may cause biomaterial-associated infection.

Postsurgical infection from using a computed tomography-based hip navigation system during total hip arthroplasty

PURPOSE

A computed tomography (CT)-based hip navigation system is a useful tool for achieving precise implant alignment angle. However, it has the disadvantage of prolonged procedure duration. A prolonged procedure duration may increase the incidence of postoperative surgical site infection (SSI) or periprosthetic joint infection (PJI) following primary THA. Studies identifying whether CT-based hip navigation system increases the incidence of SSI and PJI compared to the free-hand technique for total hip arthroplasty (THA) are rare. The study aimed to assess whether the CT-based hip navigation system can cause SSI and PJI compared to the free-hand technique.

METHODS

We investigated 366 patients with osteoarthritis who completed the minimum 2-year follow-up and underwent primary THAs (n = 435), including 70 hips in 62 patients of the non-navigation group and 365 hips in 304 patients of the navigation group. We compared the incidence rate of SSI and PJI between the non-navigation group and navigation group.

RESULTS

Only three patients in the navigation group (0.8%) developed SSI or PJI, while no patient developed SSI or PJI in the non-navigation group. There was no significant difference in the incidence rate of SSI or PJI between the two groups (P = 1.0), although the mean operation time in the navigation group was about 20 min longer.

CONCLUSIONS

CT-based hip navigation system may not be associated with SSI or PJI after primary THA, although it prolongs the operation time.

Evolving concepts in bone infection: redefining "biofilm", "acute vs. chronic osteomyelitis", "the immune proteome" and "local antibiotic therapy"

Osteomyelitis is a devastating disease caused by microbial infection of bone. While the frequency of infection following elective orthopedic surgery is low, rates of reinfection are disturbingly high. Staphylococcus aureus is responsible for the majority of chronic osteomyelitis cases and is often considered to be incurable due to bacterial persistence deep within bone. Unfortunately, there is no consensus on clinical classifications of osteomyelitis and the ensuing treatment algorithm. Given the high patient morbidity, mortality, and economic burden caused by osteomyelitis, it is important to elucidate mechanisms of bone infection to inform novel strategies for prevention and curative treatment. Recent discoveries in this field have identified three distinct reservoirs of bacterial biofilm including: Staphylococcal abscess communities in the local soft tissue and bone marrow, glycocalyx formation on implant hardware and necrotic tissue, and colonization of the osteocyte-lacuno canalicular network (OLCN) of cortical bone. In contrast, S. aureus intracellular persistence in bone cells has not been substantiated in vivo, which challenges this mode of chronic osteomyelitis. There have also been major advances in our understanding of the immune proteome against S. aureus, from clinical studies of serum antibodies and media enriched for newly synthesized antibodies (MENSA), which may provide new opportunities for osteomyelitis diagnosis, prognosis, and vaccine development. Finally, novel therapies such as antimicrobial implant coatings and antibiotic impregnated 3D-printed scaffolds represent promising strategies for preventing and managing this devastating disease. Here, we review these recent advances and highlight translational opportunities towards a cure.