Aim Cefazolin, a first generation cephalosporin, is the standard of care for perioperative antibiotic prophylaxis in hip and knee arthroplasty patients. Research has shown that prosthetic joint infection (PJI) rates are significantly higher when non-cefazolin antibiotics are used for perioperative TKA and THA prophylaxis. Cefazolin contains an R1 side chain that has not shown cross reactivity with other cephalosporins. Despite these data, the declaration of a cephalosporin allergy causes uncertainty regarding the optimal antibiotic choice in these patients. The purpose of this study was to determine the safety of administering perioperative cefazolin in patients with a cephalosporin allergy undergoing joint arthroplasty. Methods We identified all patients (n=1267) with a documented cephalosporin allergy who underwent total hip or knee arthroplasty at a high volume academic medical center from 2016-2024. We compared patients who received perioperative cefazolin despite the presence of a cephalosporin allergy (n=481) to patients who received alternative antibiotic prophylaxis (n=786). The primary outcome measure was the incidence of IgE mediated allergic reactions within the first 72 hours postoperatively. Secondary outcomes included 90-day complication rates including PJI, C. difficile infection, adverse events and readmission. Results The incidence of allergic reaction in cephalosporin allergic patients who received cefazolin was 0.0% (0/481) compared to 0.51% (4/786) in patients who received alternative antibiotics prophylaxis (p=0.12). There were no significant differences in the incidences of PJI (0.23% vs. 0.30%; p=0.83), C. difficile infection (0.0% vs. 0.0%) or readmission (3.95% vs. 4.34%; p=0.75) within 90 days. There was one adverse event related to cefazolin administration which was urethral irritation and was self-limited. There were three adverse events related to alternative antibiotic prophylaxis including cutaneous manifestations, GI distress and headache in a patient with idiopathic intracranial hypertension. All four allergic reactions in the alternative antibiotic prophylaxis cohort required supportive treatment with IV corticosteroids, fluids and antihistamines. Conclusion In this cohort of hip and knee arthroplasty patients, cefazolin administration in the setting of a cephalosporin allergy resulted in a 0.0% incidence of IgE mediated allergic reactions. These data and the fact that cefazolin's unique R1 side chain is not shared by any other cephalosporins suggests that cefazolin can safely be administered to most patients with a documented cephalosporin allergy.
Precision or Pitfall? Evaluating the Accuracy of ICD-10 Coding for Cemented Total Hip Arthroplasty
Background: The International Statistical Classification of Diseases and Related Health Problems, 10th Revision, Procedure Coding System (ICD-10-PCS) was adopted in the U.S. in 2015. Proponents of the ICD-10-PCS have stated that its granularity allows for a more accurate representation of the types of procedures performed by including laterality, joint designation, and more detailed procedural data. However, other researchers have expressed concern that the increased number of codes adds further complexity that leads to inaccurate and inconsistent coding, rendering registry and research data based on ICD-10-PCS codes invalid and inaccurate. We aimed to determine the accuracy of the ICD-10-PCS for identifying cemented fixation in primary total hip arthroplasty (THA). Methods: We retrospectively reviewed all cemented primary THAs performed at 4 geographically diverse, academic medical centers between October 2015 and October 2020. Cemented fixation was identified from the ICD-10-PCS coding for each procedure. The accuracy of an ICD-10-PCS code relative to the surgical record was determined by postoperative radiograph and chart review, and cross-referencing with institution-level coding published by the American Joint Replacement Registry (AJRR) was also performed. Results: A total of 552 cemented THA cases were identified within the study period, of which 452 (81.9%) were correctly coded as cemented with the ICD-10-PCS. The proportion of cases that were correctly coded was 187 of 260 (72%) at Institution A, 158 of 185 (85%) at Institution B, 35 of 35 (100%) at Institution C, and 72 of 72 (100%) at Institution D. Of the 480 identified cemented THA cases at 3 of the 4 institutions, 403 (84%) were correctly reported as cemented to the AJRR (Institution A, 185 of 260 cases [71%]; Institution B, 185 of 185 [100%]; and Institution C, 33 of 35 [94%]). Lastly, of these 480 identified cemented THA cases, 317 (66%) were both correctly coded with the ICD-10-PCS and correctly reported as cemented to the AJRR. Conclusions: Our findings revealed existing discrepancies within multiple institutional data sets, which may lead to inaccurate reporting by the AJRR and other registries that rely on ICD-10-PCS coding. Caution should be exercised when utilizing ICD-10 procedural data to evaluate specific details from administrative claims databases as these inaccuracies present inherent challenges to data validity and interpretation.