Published 11/25/2024
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Cailin Conner
A study presented at the AAOS 2024 Annual Meeting found no association between risk of periprosthetic joint infection (PJI) and extended oral prophylaxis following total joint arthroplasty (TJA).
According to presenting author J. Ryan Martin, MD, of Vanderbilt University Medical Center, “Recently, there has been a shift in the use of extended oral antibiotics (EOA) following primary total joint replacement.” Dr. Martin cited a 2018 study in the Journal of Bone and Joint Surgery that found that the infection risk in total hip arthroplasty (THA) and total knee arthroplasty (TKA) patients categorized as “high-risk” who underwent EOA was comparable to that of low-risk patients without EOA.
The risk of PJI was also notably lower in high-risk patients who underwent EOA than in high-risk patients without EOA. Based on those findings, Dr. Martin said, “In 2020, my institution began utilizing EOA for all patients undergoing primary total joint replacement.”
As Dr. Martin explained to AAOS Now, “We had two primary concerns with this clinical practice change. First, given our low infection risk at our institution, would the use of EOA result in a reduction in PJI in our entire patient population? Furthermore, would we even see the same benefit in risk reduction in high-risk patients? Second, given the potential risks of antibiotic resistance and antibiotic side effects, we wanted to evaluate this as a secondary outcome.”
Utilizing a retrospective study design, the researchers analyzed data on 4,590 patients who underwent primary THA or TKA between 2018 and 2022. Starting in 2020, all patients received a 10-day course of EOA prophylaxis following surgery. The cohort was divided into two groups: those who received EOA (n = 1,774 patients) and those who did not (n = 2,816 patients). Ninety-day and 1-year outcomes, specifically the incidence of PJI, were compared between groups, with additional subgroup analysis conducted on high-risk patients.
The results of the study revealed no significant differences in 90-day or 1-year PJI rates between the EOA and no EOA cohorts (0.96 percent versus 0.82 percent; P = 0.6). Further analysis of THA and TKA subgroups also showed no significant variance in PJI rates. High-risk patients, specifically analyzed in a subgroup, demonstrated no discernable benefit from EOA in terms of postoperative PJI (1.21 percent versus 1.16 percent, P = 0.8).
Additionally, the study found no differences in the incidence of Clostridioides difficile (C. diff) colitis (0.06 percent versus 0.07 percent; P >0.9) or antibiotic resistance among those who developed PJI (58 percent versus 83 percent; P >0.2).
Although no significant differences in antibiotic resistance or the incidence of C. diff colitis were identified, it was observed that most patients who experienced PJI exhibited antibiotic resistance. “While we can only speculate the reasons for this, it is concerning that most bacteria in our area are resistant,” Dr. Martin remarked.
Dr. Martin and his colleagues were “initially surprised” by the results of their study. “One clinical takeaway from this study is that EOA was not associated with a significant reduction in the risk of 90-day PJI in all comers or high-risk patient populations,” he said. “Our results appear to contradict the widespread adoption of EOA for all high-risk patients at institutions where the risk of infection is much lower. Furthermore, given the known risks of antimicrobial resistance, antibiotic stewardship should be considered. It is concerning that 80 percent of infections in our study were with resistant bacteria.”
The study had several limitations. In addition to the integration of EOA, other risk-reduction strategies may have been implemented that impacted the incidence of PJI and were not captured in this study. Moreover, despite the inclusion of 4,576 patients in the study, a larger investigation might have been able to identify smaller differences and consider additional variables. Furthermore, the dataset originated from a single academic institution, so the generalizability of the results is uncertain.
Another limitation lies in the low incidence of infection in high-risk patients. “While clinically we are relieved to see our infection risk was so low in this patient population, it substantially increases the number of patients needed to detect a difference if one were to exist,” Dr. Martin said.
At present, there are conflicting data regarding the benefits of EOA in high-risk TJA patients, with this retrospective study and the Journal of Bone and Joint Surgery study, involving comparable patient cohorts, yielding markedly different results. Therefore, according to Dr. Martin, “A large, prospective, multicenter study is necessary to answer this question. Specifically, are EOA in high-risk patients associated with a significant reduction in PJI?”
Dr. Martin’s coauthors of “Not So Fast: Extended Oral Antibiotic Prophylaxis Does Not Reduce 90-Day Infection Rate following Primary Total Hip and Knee Arthroplasty” are Gregory G. Polkowski, MD, MSc, FAAOS; Jacob D. Schultz, MD; Jacob M. Wilson, MD; Jade B. Flynn, PharmD; Sanar Yokhana, MD; and Stephen M. Engstrom, MD, FAAOS.
Cailin Conner is the former associate editor of AAOS Now.
Reference
- Inabathula A, Dilley JE, Ziemba-Davis M, 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(24):2103-9.