Expanded Gram-Negative Antimicrobial Prophylaxis Reduces Surgical Site Infections in Hip Arthroplasty

Area of Science:

• Orthopedic Surgery
• Infectious Disease
• Pharmacology

Background:

• First-generation cephalosporins are standard antibiotic prophylaxis for implants.
• Gram-negative bacilli increasingly cause surgical site infections (SSIs), particularly in hip procedures (30%) compared to knee procedures (10%).
• Expanded Gram-Negative Antimicrobial Prophylaxis (EGNAP) was implemented for hip arthroplasty to combat resistant pathogens.

Purpose of the Study:

• To evaluate the impact of EGNAP on SSI rates in primary total hip arthroplasty patients.
• To assess the efficacy of an adjusted antibiotic protocol in reducing gram-negative bacterial infections post-hip surgery.

Main Methods:

• A case-control study involving 10,084 patients undergoing hip or knee arthroplasty.
• Hip arthroplasty patients received cefazolin alone (pre-July 2012) or cefazolin plus EGNAP (gentamicin or aztreonam) (post-July 2012).
• Knee arthroplasty patients served as a control group, not receiving EGNAP.

Main Results:

• The SSI rate in hip arthroplasty patients decreased from 1.19% to 0.55% after implementing EGNAP (P = .05).
• No significant difference in SSI rates was observed in knee arthroplasty patients (1.08% vs 1.02%, P = .999).
• The addition of EGNAP was associated with a statistically significant reduction in SSIs for hip procedures.

Conclusions:

• The addition of EGNAP to standard prophylaxis is a safe and effective strategy for reducing SSIs in hip arthroplasty.
• This enhanced prophylactic regimen addresses the challenge of increasing gram-negative bacterial infections in orthopedic surgery.
• EGNAP demonstrates a clear benefit in preventing surgical site infections following total hip replacement.