What is the recommended timing and dosage of preoperative antibiotics for foot and ankle surgeries where a tourniquet is applied?

Preoperative Antibiotic Administration for Foot and Ankle Surgeries with Tourniquet Application

For foot and ankle surgeries with tourniquet application, preoperative antibiotics should be administered within 60 minutes before incision and completed before tourniquet inflation to ensure adequate tissue concentrations throughout the procedure. 1

Timing of Administration

• Antibiotic prophylaxis should be started within 30-60 minutes before surgical incision to ensure adequate serum and tissue concentrations during the period of potential contamination 1
• The antibiotic infusion must be completed before tourniquet inflation to allow adequate distribution to the surgical site 1
• When using vancomycin, infusion should be started early enough to be completed at least 30 minutes before the procedure due to its longer administration time 1

Recommended Antibiotics and Dosages

• For standard foot and ankle surgeries with implantation of foreign material:

  • First choice: Cefazolin 2g IV slow infusion 1
  • For procedures lasting >4 hours: Additional dose of 1g cefazolin 1, 2
  • For patients with beta-lactam allergy: Clindamycin 900 mg IV slow infusion or vancomycin 30 mg/kg (infused over 120 minutes) 1

• For closed fractures requiring intrafocal osteosynthesis:

  • Cefazolin 2g slow IV with reinjection of 1g if duration >4 hours 1, 2
  • Alternative options include cefamandole 1.5g IV or cefuroxime 1.5g IV with reinjection if duration >2 hours 1

Duration of Prophylaxis

• Antibiotic prophylaxis should generally be limited to the operative period 1
• For most foot and ankle procedures, a single preoperative dose is sufficient 1
• In some cases, prophylaxis may be extended up to 24 hours maximum, but never beyond 1
• The presence of surgical drains does not justify extending antibiotic prophylaxis 1

Special Considerations with Tourniquets

• Recent research shows that administering cefuroxime 15-45 minutes prior to tourniquet inflation results in sufficient concentrations in bone and tissue throughout a 90-minute tourniquet application 3, 4
• For longer procedures with tourniquet times exceeding 90 minutes, consider administering a second dose of antibiotics at the time of tourniquet release to maintain adequate postoperative concentrations 3
• Tourniquet-induced tissue ischemia typically resolves within 2.5 hours after release 3

Efficacy and Risk Factors

• Single-dose antibiotic prophylaxis significantly reduces the incidence of superficial and deep wound infections in orthopedic procedures 1
• Host factors (such as ASA score) and duration of surgery appear to play a larger role in surgical site infection risk than the precise timing of antibiotic administration within the recommended window 5
• For routine elective foot and ankle surgeries without risk factors, the absolute benefit of prophylactic antibiotics may be small 6

Common Pitfalls to Avoid

• Administering antibiotics after tourniquet inflation, which prevents adequate distribution to the surgical site 1
• Extending prophylaxis beyond 24 hours, which increases the risk of antibiotic resistance without providing additional benefit 1
• Failing to adjust dosing for patients with renal impairment 2
• Not considering a second dose for procedures that exceed two half-lives of the chosen antibiotic 1, 2

Remember that antibiotic prophylaxis is just one component of infection prevention. Proper aseptic technique, meticulous surgical approach, and appropriate management of patient risk factors are equally important in preventing surgical site infections 1.