JOA - 2026-07-13 - Journal Article
Cefazolin Prophylaxis in Patients Over 120 Kilograms: Comparison of Periprosthetic Joint Infection Following Total Hip Arthroplasty With Two Versus Three Grams Dosing.
Hurka KL, Rumalla KC, Memon R, Sohn MO, Desai RM, Edelstein AI
Topics
Key Takeaway
In THA patients >120 kg, 3g cefazolin prophylaxis did not significantly reduce 90-day PJI compared to 2g (1.6% vs 1.4%; OR 1.16, 95% CI 0.43–3.07), though Bayesian analysis showed 87% probability of benefit with higher dosing.
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Summary
This retrospective cohort study used a national database to compare 90-day PJI rates in primary THA patients >120 kg receiving 2g versus 3g cefazolin prophylaxis between April 2016 and July 2022. Multivariable logistic regression adjusting for age, race, payer status, length of stay, and Elixhauser Comorbidity Index found no significant difference in PJI risk (OR 1.16, 95% CI 0.43–3.07, P=0.77). Bayesian posterior analysis demonstrated 87% probability that 3g dosing reduces PJI, indicating a clinically plausible but statistically unconfirmed benefit.
Key Limitation
The total sample size is not reported, and with a baseline PJI rate of ~1.5%, the study is likely underpowered to detect the small absolute risk differences that would be clinically meaningful in this high-risk population.
Original Abstract
BACKGROUND
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 kilograms, supporting evidence is limited and conflicting. This study compared PJI incidence among patients receiving two versus three grams of prophylactic cefazolin.
METHODS
A retrospective cohort study was conducted using a large national database. Adult patients weighing greater than 120 kilograms 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-day PJI risk. A Bayesian posterior analysis using the same model quantified uncertainty.
RESULTS
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.
CONCLUSION
Among THA patients weighing ≥ 120 kilograms, 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.