Cefazolin Prophylaxis in Patients ≥120 Kilograms: Comparison of Periprosthetic Joint Infection Following Total Hip...

High-body weight total hip arthroplasty (THA) patients face elevated risks for postoperative complications such as periprosthetic joint infection (PJI). Although guidelines recommend three grams of cefazolin for patients weighing greater than 120 kg, supporting evidence is limited and conflicting. This study compared PJI incidence among patients receiving two versus three grams of prophylactic cefazolin.

A retrospective cohort study was conducted using a large national database. Adult patients weighing greater than or equal to 120 kg who underwent primary THA between April 2016 and July 2022 and received cefazolin prophylaxis were included. Patients were grouped by dose (two versus three grams). A multivariable logistic regression adjusting for age, race, ethnicity, payer status, lengths of stay, and Elixhauser Comorbidity Index assessed 90-days PJI risk. A Bayesian posterior analysis using the same model quantified uncertainty.

The 90-day PJI rates did not differ significantly (1.4 versus 1.6%; P = 0.17). On multivariable analysis, cefazolin dose was not associated with PJI risk (odds ratio 1.16; 95% confidence interval 0.43 to 3.07; P = 0.77). Bayesian analysis demonstrated an 87% probability that higher dosing reduced PJI risk, suggesting a moderate, but uncertain benefit.

Among THA patients weighing ≥ 120 kg, three grams of cefazolin was not associated with a statistically significant reduction in PJI risk compared to two grams. However, Bayesian analysis suggested a moderate probability that a three-gram dosing may reduce infection risk. These findings do not provide sufficient evidence to recommend changing current guidelines, but highlight ongoing uncertainty and the need for larger studies to define optimal prophylactic dosing in this population.