The type of solution surgeons use to disinfect a patient’s skin before surgery affects the risk of surgical site infection, new research from an international trial jointly led by McMaster University and the University of Maryland School of Medicine shows.

Researchers of the PREPARE trial, which enrolled nearly 8,500 participants at 25 hospitals in Canada and the United States, found the use of iodine povacrylex in alcohol to disinfect a patient’s skin could prevent surgical site infection in thousands of patients undergoing surgery for a closed fracture each year.

The findings, published on Feb. 1, 2024 in The New England Journal of Medicine, are could lead many hospitals to consider a policy change to use of iodine povacrylex in alcohol for fracture surgeries.

“This trial represents a highly successful collaboration between McMaster University, the University of Maryland School of Medicine, and 25 trauma centers across Canada and the United States,” says Sheila Sprague, co-principal investigator of the trial and an associate professor in the department of Surgery at McMaster.

“This multi-centre approach allowed us to quickly and efficiently address an important clinical research question that will lead to the prevention of thousands of infections each year.”

“Importantly, our collaborations will continue to grow to address other unanswered questions in orthopaedic trauma surgery.”

The trial included 6,785 patients undergoing surgery to treat a closed lower extremity or pelvic fracture and 1,700 patients undergoing surgery to treat an open fracture. Closed fractures occur when the bone is broken, but the skin is intact.

Open fractures have an exceptionally high risk of infection due to the open wound and bone being exposed to environmental bacteria for hours before surgery.

Researchers compared the two most commonly used antiseptic products in the U.S. and Canada. Patients with closed fractures randomized to receive 0.7 per cent iodine povacrylex in 74 per cent isopropyl alcohol for skin antisepsis experienced fewer post-operative surgical site infections than those randomized to receive two per cent chlorhexidine gluconate in 70 per cent isopropyl alcohol.

In patients with open fractures, the risk of infection was similar between the two different antiseptic skin preparation solutions.

“Although some guidelines favour antisepsis with chlorhexidine gluconate over an iodophor, all recommendations have recognized a lack of consensus with respect to the most effective agent,” says Gerard Slobogean, co-principal investigator of the trial and an orthopaedic trauma surgeon at the University of Maryland’s R Adams Cowley Shock Trauma Center.

“Our results suggest that the use of iodine povacrylex in alcohol as preoperative skin antisepsis could prevent surgical-site infection in thousands of patients with closed fractures each year.”

The authors say, to their knowledge, this randomized controlled trial is substantially larger than prior trials, which allowed them to detect important differences in infection. While the trial only included fracture surgery patients, they say that the findings might also be relevant to other surgical disciplines.

This research was supported by the PREP-IT Investigators, which includes a network of over 200 physicians, allied health-care professionals, trauma patients, and clinical researchers. This trial was funded by the Patient-Centered Outcomes Research Institute and the Canadian Institutes of Health Research (Foundation Grant).