Antibiotic Prophylaxis

Foundations & Timing - Prophylaxis Kick‑off

• Definition: Antibiotics given before surgical incision or tissue contamination to prevent infection.
• Goal: Prevent Surgical Site Infections (SSI); vital in orthopaedics (implants, high SSI risk).
• Principles:
  • Timing: Pre-operative administration is key.
    • Intra-operative re-dosing: For prolonged surgeries or major blood loss.
  • Duration: Usually single dose; ≤ 24 hours post-operatively.
• Surgical Wounds & Prophylaxis:
  • Clean: (e.g., arthroplasty) - Prophylaxis needed.
  • Clean-Contaminated: (e.g., recent open fractures) - Prophylaxis needed.

⭐ Administer first prophylactic antibiotic dose within 60 minutes before surgical incision (or within 120 minutes for Vancomycin/fluoroquinolones).

Agents & Regimens - Ortho's Antibiotic Shield

• Standard Prophylaxis: Cefazolin
  • Spectrum: Excellent against Gram-positive cocci (Staphylococcus aureus, S. epidermidis), common surgical site pathogens.
  • Adult Dose: 2g IV administered 30-60 minutes before surgical incision.
  • Weight-based adjustment: If patient weight >120kg, use 3g IV.
  • Intraoperative re-dosing: Every 4 hours (or after 2 half-lives) during prolonged procedures to maintain adequate tissue concentrations.
• Penicillin/Beta-Lactam Allergy:
  • For true IgE-mediated (anaphylactic) reactions:
    • Clindamycin: 600-900mg IV.
    • Vancomycin: 15mg/kg IV (infused over 60-120 min).
  • 📌 Vanco for MRSA/Allergy.
• MRSA Considerations:
  • Screen high-risk patients (e.g., prior MRSA, nursing home, recent hospitalization).
  • If MRSA risk is high or confirmed colonization:
    • Vancomycin: 15mg/kg IV (preferred).
    • Teicoplanin: Alternative (loading dose then maintenance).

⭐ For patients with a true IgE-mediated penicillin allergy, Clindamycin or Vancomycin are common alternative prophylactic antibiotics in orthopaedic surgery.

Procedure‑Specific Protocols - Surgical Safeguards

• Total Joint Arthroplasty (TJA - Hip, Knee), Fracture fixation (ORIF), Spine surgery:
  • Prophylaxis: Cefazolin (or other 1st/2nd gen cephalosporin).
  • Administer within 60 minutes before surgical incision.
• Open Fractures (Gustilo-Anderson classification):
  • Grade I/II: Cefazolin. Duration: 24-48 hours.
  • Grade III: Cefazolin + Aminoglycoside (e.g., Gentamicin). (Extensive contamination: consider Pip-Tazo). Duration: 48-72 hours or until soft tissue coverage.
• Arthroscopy:
  • Generally not routine.
  • Consider for prolonged procedures (>2 hours), or with implants (e.g., ACL reconstruction), or in immunocompromised patients.
• Special Situations:
  • Immunocompromised patients, revision surgeries: May require broader spectrum or tailored prophylaxis.
  • Known MRSA colonization: Vancomycin or Teicoplanin recommended.
• Duration:
  • Typically not exceeding 24 hours post-op for most procedures.
  • Prolonged use ↑ risk of resistance and side effects.

⭐ For uncomplicated primary Total Joint Arthroplasty, antibiotic prophylaxis is typically recommended for no more than 24 hours post-operatively.

High‑Yield Points - ⚡ Biggest Takeaways

• Cefazolin is the drug of choice for most orthopaedic surgical prophylaxis.
• Administer IV antibiotics within 60 minutes before skin incision.
• Use vancomycin or clindamycin for beta-lactam allergy.
• Vancomycin infusion: start 1-2 hours pre-incision (longer infusion).
• Redose antibiotics for surgeries >4 hours or with blood loss >1500 mL.
• Discontinue prophylaxis within 24 hours post-operatively.
• Consider MRSA coverage (vancomycin) for high-risk patients or high institutional MRSA prevalence.