AAOS 2025 President’s Symposium: Infection is still an unsolved problem in orthopaedics

Infection is one of the most common postoperative complications in the treatment of total joint arthroplasty and fractures. There remains significant room for improvement in infection prevention, with some surgeries still having a greater than 10% infection rate. At the AAOS 2025 Annual Meeting, Past President Paul Tornetta III, MD, MBA, FAAOS, chose this important topic to feature in his President’s Symposium, “Orthopaedic infections: the last frontier.”

The topic of infection is very personal to symposium co-moderator William T. Obremskey, MD, MPH, FAAOS, professor of orthopaedic surgery at Vanderbilt University, who was infected with necrotizing fasciitis in 2009.

“Since then, I spent a lot of time in working with the military, the [Orthopaedic Trauma Association], and international groups trying to develop clinical practice guidelines and determine what is the best evidence to help us,” Dr. Obremskey shared of his work in the field of postoperative infection. “I am frustrated with [research] that says, ‘We cannot decide for or against,’ when as a clinician, you have to make a decision.”

The symposium was designed to do just that: give clinicians the best information available to make decisions for patients. Speakers at the session covered a wide variety of useful topics related to infection prevention, treatment, and what’s next in the field.

The root of the problem
The symposium began with Matthew P. Abdel, MD, FAAOS, the Andrew A. and Mary S. Sugg Professor of Orthopedic Surgery and chair of the surgical and procedural practice at Mayo Clinic in Rochester, Minnesota, who set the stage on periprosthetic joint infection (PJI). He called PJI a “dramatic and disconcerting problem” with a contemporary prevalence estimated to be about 1% to 2%. However, PJI after aseptic revision of total hip or total knee arthroplasty has an infection prevalence of 2% to 7%.

The American Joint Replacement Registry 2024 Annual Report revealed that infection and its associated inflammatory reaction was the number one reason for hip and knee revisions overall, as well as all early hip and knee revisions.

“What unique feature leaves this as the number one unsolved problem?” Dr. Abdel asked. The answer is biofilm, which is refractory to many antimicrobial agents and to the host immune system.

Dr. Abdel detailed many of the currently available treatments for infection in total hip and total knee arthroplasty, calling them archaic and time consuming. Finally, he emphasized the profound economic impact of these infections; hospital costs for PJI of the hip and knee are expected to be about $1.85 billion annually by 2030. Combating this problem will require better work toward prevention and innovation.

Infection prevention
Next, Craig J. Della Valle, MD, FAAOS, the Aaron G. Rosenberg Professor of Orthopaedic Surgery and chief of adult reconstruction at Rush University Medical Center, discussed strategies for PJI prevention. There are multiple strategies for optimizing a patient preoperatively for PJI, according to Dr. Della Valle, including modifying obesity, nutrition, diabetes, and smoking.

“We as orthopaedic surgeons can have more impact on [helping] patients to kick smoking than a primary care provider because we have a carrot they want,” Dr. Della Valle said. “Don’t underestimate your ability to help patients quit.”

Use of appropriate perioperative antibiotics is also important, with cefazolin “strongly preferred,” he advised.

“Most patients with a self-reported allergy to penicillin can safely get cefazolin,” he said, adding that research has shown that not using this treatment increased the risk of PJI.

Strategies for skin preparation have also changed. It is now widely accepted that electric clippers should be used in place of a razor, and that this should be done outside of the OR. Alcohol-based skin prep is generally accepted, but there is more controversy around the use of adhesive skin drapes and chlorhexidine wipes.

Surgeons also must work to decrease bacteria in the wound. “To close and make the assumption that the wound is free of bacteria is wrong,” Dr. Della Valle said. He noted that although there are several methods to decrease bacteria, his preference is diluted betadine lavage.

Treatment options
Antonia F. Chen, MD, MBA, FAAOS, chair and professor at University of Texas Southwestern, walked attendees through some of the current treatment options for PJI. Dr. Chen emphasized that treatment of PJI should always be taken seriously.

Oral antibiotics can be used in patients who cannot tolerate surgery, but Dr. Chen said it is “probably not ideal in most cases.” For patients who are able to undergo surgery, the surgical procedure should be selected based on timing of the infection relative to the original surgery and other factors. She discussed different classifications for PJI staging, including the McPherson classification, the Zimmerli classification, and the ICM Prosthetic Joint Infection definition. The staging of these infections can dictate surgical technique and approach.

“Surgical technique is similar for all procedures in that you want to do extensive debridement,” Dr. Chen said. “In infection, you want to clear out everything necrotic. If you are not spending longer on this than doing anything else, then you are not doing debridement correctly.”

She discussed methods for physical debridement and chemical debridement and walked through details related to debridement, antibiotics, and implant retention (DAIR); double DAIR; two-stage exchange arthroplasty — both articulating and non-articulating; and abbreviated two-stage exchange arthroplasty. Finally, Dr. Chen discussed how to select the appropriate type and duration of antibiotic treatment, addressing gram-positive organisms, gram-negative organisms, and antifungals.

The symposium featured additional presentations related to management of infection in the fracture setting, including prevention strategies and current treatment options. A recording of the full session is available through AAOS Annual Meeting OnDemand. Visit aaos.ondemand.org to get started.

Leah Lawrence is a freelance writer for AAOS Now.