Abstract
Introduction
First generation cephalosporins remain the gold standard perioperative antibiotic for total hip and knee arthroplasty (THA, TKA). However, some patients have documented or self-reported allergies to antibiotics, most commonly penicillin, that result in changes to perioperative antibiotic coverage. Furthermore, patients testing positive for methicillin resistant staphylococcus aureus (MRSA) represent another group where an alternative to cefazolin, typically vancomycin, is often chosen for perioperative prophylaxis. The aims of this study were to 1) characterize the antibiotic choices for perioperative prophylaxis at the time of primary TKA and THA, 2) assess the efficacy of a preoperative antibiotic allergy testing program, and 3) determine rates of periprosthetic joint infection (PJI) based on perioperative antibiotic regimen.
Methods
We evaluated all patients undergoing primary TKA or THA at a single academic institution from January 2004-May 2017, yielding a cohort of 29,695 patients. A series of institutional databases were combined to determine which patients underwent antibiotic allergy testing prior to surgery, outcomes from the allergy consultation, perioperative antibiotic management strategy, and survivorship free of infection until final follow-up.
Results
Antibiotic allergy testing was performed in 3,411 patients (11.5%) on the basis of a patient provided history of possible penicillin or cephalosporin allergy. Among those tested, 3,310 patients (97.0%) were cleared by the allergist to use cephalosporins in the perioperative period and 2,883 patients (87.1%) eventually received cefazolin. For the entire cohort, 28,174 patients (94.9%) received an operative antibiotic regimen including cefazolin and 1,521 patients (5.1%) received non-cefazolin antibiotics, most commonly vancomycin or clindamycin.
Survivorship free of PJI was significantly higher among patients receiving cefazolin compared to non-cefazolin antibiotics with the most rapid divergence occurring within 2 months of surgery (p<0.001) (Figure 1). Survivorship free of PJI in the cefazolin compared to the non-cefazolin groups was 99.40% vs 99.34% at 1 month, 99.11% vs 98.55% at 2 months, 98.83% vs 98.22% at 1 year, and 98.15% vs 96.96% at 10 years (Table 1). Notably, the increased PJI rate observed in the non-cefazolin group was not attributable to high preoperative MRSA prevalence as 0 of the 38 PJIs grew MRSA on culture. The number needed to treat with cefazolin to prevent 1 PJI was 164 patients at 1-year and 84 patients at 10-years. Therefore, potentially 6,098 PJIs could be prevented by 1-year and 11,905 by 10-years in a cohort of 1,000,000 primary TKA and THA patients.
Conclusions
This study demonstrates a significantly higher rate of PJI when non-cefazolin antibiotics are used for prophylaxis during primary TKA and THA, which is likely attributable to the superior spectrum of coverage for common PJI organisms compared to vancomycin or clindamycin. This is supported by the increased rate of non-MRSA PJI observed in the non-cefazolin cohort. Furthermore, cefazolin has been shown to act synergistically with vancomycin against MRSA. This work highlights the positive impact of a formal preoperative antibiotic allergy testing program to increase cefazolin usage. Also, surgeons may consider using cefazolin as a dual agent in the case of known MRSA colonization, whenever possible for PJI prophylaxis during TKA and THA.
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