Chronic antibiotic suppression may successfully treat periprosthetic joint infections

Geoffrey H. Westrich, MD

The study by Rebecca G. Burr, MD, and colleagues represents a small number of patients. They had 45 patients with 31 TKAs and 14 THAs. When they looked at reoperation, they found THA patients do better than TKA patients, which we have found in our previous research as well. They found that gram-positive infections were less likely than those with a gram-negative infection to require reoperation. I would say that Streptococcus bacteria is a gram-positive organism and patients with Streptococcus infections are more easily treated and tend to do well. Staphylococcus, especially some of the more resistant Staphylococcus bacteria like MRSA, tends to be harder to eradicate and there are studies that show that trying to do a debridement, antibiotic and implant retention (DAIR) with a MRSA infection has about an 80% failure rate over time. So, we have found that the type of bacteria plays a critical role as well as the patient’s immune system. Healthier, well-nourished patients with a robust immune system tend to do better than patients with a poor immune system. In the study from Burr and colleagues, severe antibiotic side effects were rare and infected THA patients did better than infected TKA patients. Those were the results. There were a small number of patients and limited conclusions.

Our article published in the Journal of Arthroplasty in 2020 was a systematic review of seven retrospective studies with 437 patients with periprosthetic joint infections that were treated with a DAIR and then antibiotic suppression. We found that the overall success rate of DAIR with antibiotic suppression was 75% and the overall adverse effects of taking long-term antibiotics was 15.4%, but only 4.3% had to discontinue the antibiotics. So, although some patients may have had problems, it was still a small number of patients who had to stop the antibiotics.

What our study showed was that the evidence is inconclusive. There haven’t been good, prospective randomized studies on the duration of antibiotic suppression following infected hip and knee replacements. As such, it is unclear if we should use suppressive antibiotics for 6 weeks, 3 months, 1 year or longer. In the future, we hope that randomized, prospective studies will answer these questions. The downside of such studies, however, is that randomizing a patient to stopping antibiotic suppression after 6 months may potentially put the patient at risk for recurrence of the joint infection and may result in the patient needing further surgery if the infection recurs. Recurrence of infection would usually not be treated with another DAIR procedure and may require removal of the infected prosthesis, which is a larger surgical procedure with greater risks to the patient. That is the downside of doing these prospective studies, but that is also the right way and best way to know what’s the ideal length of time for antibiotic suppression after a DAIR procedure.

Reference:

Malahias MA, et al. J Arthroplasty. 2020;doi:10.1016/j.arth.2019.11.026.