In arthroplasty, which antibiotic is commonly used for perioperative prophylaxis?

• A. Vancomycin
• B. Cefazolin
• C. Ciprofloxacin
• D. Gentamicin

Answer: (B)

In preventing prosthetic joint infections, the goal of perioperative antibiotics is to reliably cover the skin flora that most often seed implants, especially Staphylococcus aureus and Staphylococcus epidermidis, with dosing that provides adequate tissue levels during the operation. Cefazolin, a first-generation cephalosporin, fits this purpose well because it has strong activity against these organisms, excellent tissue penetration, a convenient dosing regimen, and a good safety profile. Its pharmacokinetics allow a single preoperative dose to achieve effective prophylaxis during the critical window of incision and implant placement; in longer cases or those with higher body mass, dosing can be adjusted and redosed as needed.

While other antibiotics like vancomycin may be used in specific situations (for example, MRSA risk or penicillin allergy), they are not the routine first-line choice for standard arthroplasty prophylaxis due to considerations such as slower onset, potential infusion reactions, and broader spectrum that is unnecessary for typical skin flora coverage. Ciprofloxacin and gentamicin are not preferred for routine prophylaxis in this setting because they don’t reliably cover the common organisms responsible for prosthetic joint infections and carry higher risks of resistance or toxicity.

Therefore, cefazolin is the best answer for commonly used perioperative prophylaxis in arthroplasty.