Antibiotic Resistance: The Growing Threat to Orthopaedic Surgery

Modern orthopaedic surgery exists because of antibiotics. Every hip replacement, every spinal fusion, every open reduction and internal fixation of a fracture relies on the assumption that we can prevent and treat surgical site infections. Without effective antimicrobials, elective orthopaedic surgery as we know it would become unacceptably dangerous.

Antimicrobial resistance (AMR) is eroding that assumption. The World Health Organisation has declared AMR one of the top ten global public health threats. In orthopaedics specifically, the consequences are already being felt in rising rates of multi-drug resistant periprosthetic joint infections, increasing treatment failures in open fractures, and a shrinking arsenal of effective prophylactic antibiotics.

The Scale of the Problem

Globally, AMR was associated with an estimated 4.95 million deaths in 2019, and that number is projected to reach 10 million per year by 2050 if current trends continue. In orthopaedic surgery specifically:

• Methicillin-resistant Staphylococcus aureus (MRSA) accounts for 10-30% of all periprosthetic joint infections in most western countries
• Multi-drug resistant gram-negative organisms (ESBL-producing E. coli, carbapenem-resistant Klebsiella) are increasingly isolated from orthopaedic wound infections, particularly in polytrauma and open fractures
• Vancomycin-resistant Enterococcus (VRE) has emerged as a significant pathogen in revision arthroplasty, particularly in patients with prolonged hospital stays or prior antibiotic exposure
• Rifampicin-resistant staphylococci are a specific concern because rifampicin is the cornerstone of biofilm-active therapy in prosthetic joint infection

The practical impact is devastating. A patient with a PJI caused by a pan-resistant organism may face multiple revision surgeries, months of intravenous antibiotics with significant toxicity, and in worst-case scenarios, amputation or permanent antibiotic suppression therapy with no realistic prospect of cure.

Why Orthopaedic Surgery Is Particularly Vulnerable

Several features of orthopaedic surgery make it uniquely susceptible to the AMR crisis:

Implants create biofilm sanctuaries. Metallic and polyethylene implant surfaces provide an ideal substrate for bacterial adhesion and biofilm formation. Bacteria within a biofilm are 100-1000 times more resistant to antibiotics than their planktonic counterparts, regardless of their inherent resistance profile. This means even "sensitive" organisms become functionally resistant once they establish a biofilm on an implant.

Prolonged prophylaxis is common. Unlike general surgery where a single dose of prophylactic antibiotics is standard, orthopaedic practice often involves extended prophylaxis (24-48 hours or longer). Each day of antibiotic exposure exerts selective pressure on the patient's microbiome, favouring the emergence of resistant organisms.

High implant volumes. Australia alone performs over 120,000 hip and knee replacements per year. Even a small percentage increase in infection rates translates to thousands of additional complex revision cases.

Open fractures are contaminated by definition. The management of severe open fractures (Gustilo-Anderson grade IIIB and IIIC) relies heavily on empiric broad-spectrum antibiotics. As resistance patterns shift, traditional protocols (cefazolin plus gentamicin) may become inadequate.

What Is Being Done

The response is multi-pronged, spanning basic research, clinical practice, and public health policy:

New antimicrobial surfaces. Researchers are developing implant coatings that actively resist bacterial colonisation. Silver nanoparticle coatings, copper-doped titanium, and antibiotic-eluting hydroxyapatite surfaces are all in various stages of clinical testing. The most promising approach may be "smart" surfaces that release antibiotics only in response to local environmental changes (pH drop, temperature rise) associated with early infection.

Bacteriophage therapy. Phages — viruses that specifically target and kill bacteria — are attracting serious attention as an alternative or adjunct to antibiotics for musculoskeletal infections. A Phase II clinical trial at Yale University is currently evaluating phage therapy for prosthetic joint infections caused by Staphylococcus aureus. Early results have shown successful infection clearance in cases where conventional antibiotics had failed.

Antibiotic stewardship. Australian hospitals have been leaders in implementing antimicrobial stewardship programmes (ASPs), guided by the eTG (electronic Therapeutic Guidelines). In orthopaedics, this means strict adherence to evidence-based prophylaxis protocols, avoiding extended courses, and using narrow-spectrum agents whenever possible.

Local antibiotic delivery. Antibiotic-loaded bone cement (PMMA) has been a mainstay of infection prophylaxis and treatment for decades. Newer approaches include biodegradable antibiotic-eluting beads, collagen sponges impregnated with gentamicin, and even 3D-printed scaffolds that can deliver customised antibiotic combinations directly to the site of infection at concentrations hundreds of times higher than achievable with systemic therapy.

Rapid diagnostics. Next-generation sequencing (NGS) and multiplex PCR panels can now identify the causative organism and its resistance profile within hours rather than the 3-5 days required for traditional culture. This allows earlier targeted therapy and reduces the duration of empiric broad-spectrum treatment.

What Trainees and Surgeons Can Do

Individual surgeon behaviour matters in the fight against AMR:

1. Follow prophylaxis guidelines strictly. In Australia, the eTG recommends cefazolin 2g IV within 60 minutes of skin incision for most clean orthopaedic procedures. Do not add vancomycin "just in case" unless there is a documented MRSA risk factor.

2. Stop antibiotics on time. Post-operative prophylaxis beyond 24 hours has no proven benefit for primary arthroplasty and actively promotes resistance. Be disciplined about stopping.

3. Culture everything. When infection is suspected, obtain adequate tissue samples (minimum 3-5 from different locations) before starting antibiotics. An unidentified organism cannot be treated rationally.

4. Engage with your microbiology and infectious diseases colleagues early. Complex orthopaedic infections require a multidisciplinary approach. The surgeon who operates in isolation from the ID physician is likely to produce worse outcomes.

5. Support research and surveillance. Participate in local and national infection registries. Data drives policy, and policy drives change.

A Sobering Thought

The Australian Commission on Safety and Quality in Health Care has warned that without urgent action, routine procedures like hip replacements could become high-risk operations within a generation. That is not alarmism; it is a projection based on current resistance trends.

For orthopaedic surgeons, AMR is not someone else's problem. It is the most significant long-term threat to the safety and efficacy of everything we do. Every antibiotic prescription we write, every prophylaxis protocol we follow (or deviate from), and every infection we manage contributes to the trajectory of this crisis.

The time to take it seriously is now.