Efficacy of 6 Weeks Antibiotics with Prosthetic Joint Infections Save

The NEJM has published the results of a French multicenter study showing that prosthetic joint infections can be successfully managed with 6 weeks of antibiotic therapy; this was noninferior and had better outcomes compared to 12 weeks of antibiotic therapy.

Prosthetic joint infections (PJI) are usually managed with a combination of surgery and antimicrobial therapy. However, the optimal duration of antimicrobial therapy is often debated.

A multicenter, trial of 410 patients, with microbiologically proven PJI, were randomized to treatment with 6 weeks (205 patients) or 12 weeks (205 patients) of antibiotic therapy. This was an open-label, randomized, controlled, noninferiority trial. The primary outcome was persistent infection at 2 years after the completion of antibiotic therapy. Noninferiority (6 weeks vs 12 weeks of therapy) as not greater than 10 percentage points. 

Persistent infection at 2 years:

• 6-week group - 18.1%
• 12-week group - 9.4%
• Thus, the risk difference was 8.7 percentage points (95% confidence interval, 1.8 to 15.6); noninferiority was not shown.

These patients had microbiologically confirmed prosthetic joint infections and were managed with standard surgical procedures. Antibiotic therapy for 6 weeks was not shown to be noninferior to 2 weeks of antibiotic therapy. and resulted in a higher percentage of patients with unfavorable outcomes. 

A 2019 study from Lancet Infectious Disease, looked at risks for PJI amongst 679,010 primary knee replacements done in the UK between 2003 and 2013. After a median of 4.6 years, there were 3659 revision surgeries attributed to PJI.  Below are several selected, significant risk factors:

• Male sex (RR1·8)
• Younger age (RR for age ≥80 years vs <60 years 0·5)
• Elevated body-mass index (BMI; RR for BMI ≥30 kg/m2 vs <25 kg/m2 1·5)
• Inflammatory arthropathy (RR 1·4)
• Connective tissue and rheumatic diseases (RR 1·5)
• COMORBIDITIES: Chronic pulmonary disease (RR 1·2); Diabetes (RR 1·4); Liver disease (RR 2·2); Peripheral vascular disease (RR 1·4)
• Surgery for trauma (RR 1·9)
• Previous septic arthritis (RR 4·9)
• Operation under general anesthesia (RR 1·1)
• Tibial bone graft (RR 2·0)

Identifying modifiable factors and enacting proactive targeted interventions or strategies may help to reduced risk of revision for prosthetic joint infection.