Cefazolin versus Cefmetazole for Surgical Antibiotic Prophylaxis in Total Hip Arthroplasty: Impact on Postoperative Infection Rates.

INTRODUCTION: Total hip arthroplasty (THA) is a well-established procedure for advanced hip osteoarthritis, however surgical site infection (SSI) and periprosthetic joint infection (PJI) remain serious postoperative complications. Despite being the recommended first-line prophylactic antibiotic, cefazolin (CEZ) shortages in Japan in 2019 highlighted the need for alternatives. No study has compared first-generation (CEZ) and second-generation (cefmetazole [CMZ]) cephems for surgical prophylaxis in primary THA. This study examined clinical impact of CEZ versus CMZ prophylaxis on the incidence of SSI/PJI after primary THA. METHODS: This retrospective single-institution study included consecutive patients who underwent primary THA for osteoarthritis between January 2013 and December 2025. CMZ was used from 2013 to 2021 and the CEZ from 2022 to 2025. Incidence rates of SSI/PJI were compared between the groups, and odds ratios (OR) and risk differences (RD) were calculated, including subgroup analyses by sex, age, BMI, and Charlson Comorbidity Index (CCI). RESULTS: Of the 1,204 primary THAs analyzed, 715 received CMZ and 489 received CEZ. Acute and late SSI/PJI combined occurred in nine hips (1.3%) in the CMZ group and three hips (0.6%) in the CEZ group, with no statistically significant difference. Both OR and RD indicated that none of the examined patient were significantly associated with increased SSI/PJI incidence in the CMZ group compared to the CEZ group. CONCLUSION: No significant difference existed in postoperative infection rates between first- and second-generation cephems prophylaxis in primary THA. Given that supply constraints and other issues may affect CEZ availability, CMZ may be considered as an alternative.