Paper of the week: Do Extended Oral Postoperative Antibiotics Prevent Early Periprosthetic Joint Infection in Morbidly Obese Patients Undergoing Primary Total Joint Arthroplasty

Carender CN, DeMik DE, Glass NA, Noiseux NO, Brown TS, Bedard NA

The Journal of Arthroplasty 2021 (In Press)
DOI: 10.1016/j.arth.2021.03.018

Summary by: Samuel Clarkson, MD

Morbidly obese patients undergoing primary total joint arthroplasty (TJA) are known to be at an increased risk for postoperative complications including wound complications and periprosthetic joint infection (PJI). While preoperative weight loss is often encouraged, the prevalence of morbid obesity in patients undergoing primary TJA remains high. The use of an extended oral antibiotic regimen following surgery is a proposed risk mitigation strategy, however data to support this are limited. Studies that have examined the use of an extended antibiotic protocol for high-risk patients included a broad range of comorbidities rather than focusing on the morbidly obese population [1,2].

In this study, Carender et al. retrospectively identified 650 primary total hip (THA) and knee (TKA) arthroplasty cases performed at a single institution in patients with a BMI ³ 40 kg/m2. During the study period, surgeons at the authors’ institution began prescribing extended oral antibiotics to high-risk patients following data presented at the 2017 American Association of Hip and Knee Surgeons [3]. The choice of oral antibiotic was at the discretion of the attending surgeon. Overall, 437 patients in the study population received standard perioperative antibiotics, while 177 received extended oral antibiotics.

The outcome measures in the study were (1) wound complications, including dehiscence, persistent drainage, superficial SSI, (2) PJI, defined by MSIS criteria, (3) all-cause reoperation, and (4) all-cause readmission. All outcomes were determined at 90-day follow-up. Across all four outcome measures studied by the authors, there were no differences between the two groups.

The authors acknowledged the limitations of the retrospective nature of this study. First, there was a risk of selection bias. The decision of whether to use an extended oral antibiotic regimen, as well as the decision regarding which antibiotic to use, were both at the discretion of the individual surgeon. However, the authors note that the two groups were statistically similar across an array of patient and surgical factors. Another significant limitation was the short follow-up period of 90 days, however the authors speculated that if extended antibiotics were to make a difference in rates of PJI, it would likely be in early PJI rather than those that develop more than 90 days following surgery.

Despite these limitations, the authors concluded that extended oral antibiotic prophylaxis following primary TJA is not an effective method for reducing wound complications or PJI in a morbidly obese patient population.


  1. Kheir MM, Dilley JE, Ziemba-Davis M, Meneghini RM. Extended Oral Antibiotics Prevent Periprosthetic Joint Infection in High-Risk Cases: 3855 Patients With 1-Year Follow-Up. The Journal of Arthroplasty 2021.
  2. Inabathula A, Dilley JE, Ziemba-Davis M, Warth LC, Azzam KA, Ireland PH, et al. Extended Oral Antibiotic Prophylaxis in High-Risk Patients Substantially Reduces Primary Total Hip and Knee Arthroplasty 90-Day Infection Rate. J Bone Joint Surg Am 2018;100:2103–9.
  3. Avinash Inabathula, Julian Dilley, Mary Ziemba-Davis, Lucian C. Warth, Khalid A. Azzam, Philip H. Ireland, et al. Extended Oral Antibiotic Prophylaxis in High-Risk Patients Substantially Reduces Primary Total Hip and Knee Arthroplasty 90-Day Infection Rate. American Association of Hip and Knee Surgeons (AAHKS) Annual Meeting 2017.

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