No Advantage to Rifampin Combination Therapy in PJI

Adding rifampin to antibiotic treatment for staphylococcal prosthetic joint infections (PJI) offers no significant advantage, according to a new study.

While PJI is rare, occurring in 1-2% of primary surgeries and in 2-20% of revision procedures, it does lead to increased morbidity, longer hospitalizations, and higher costs. In recent years, the rising number of prosthetic joint infections in joint replacement has been a cause of concern.

Staphylococcus aureus is the second most frequent cause of prosthetic joint infection after Coagulase-negative staphylococci (12-44% vs. 30-47%).

According to the researchers, “In acute PJI and acute hematogenous spread PJI, debridement and implant retention (DAIR) combined with antimicrobial treatment is an attractive surgical option due to its lesser surgical trauma and hence limited functional impairment, but the results vary greater in the literature.”

Rifampin is typically used in the treatment of tuberculosis, but it also can be used to treat S. aureus, but it must never be used alone because of rapidly developed resistance.

In the study, “Rifampin combination therapy in staphylococcal prosthetic joint infections: a randomized controlled trial,” published August 28, 2020 in the Journal of Orthopaedic Surgery and Research, researchers compared patient outcomes between rifampin combination therapy and standard antimicrobial treatment with cloxacillin or vancomycin. The primary endpoint was no signs of infection after two years of follow-up.

They enrolled 99 patients with prosthetic joint infection after hip and knee arthroplasties in the multicenter randomized controlled trial, but only 48 of them were included in the final analysis. The patients were also treated with debridement and retention of the implant.

Overall, there were no significant differences in remission rate between the rifampin combination group (17 of 23 (74%) and the standard antimicrobial treatment group (18 of 25 (72%), relative risk 1.03, 95% confidence interval 0.73 to 1.45, p = 0.88).

The researchers wrote, “Rifampin is increasingly used in staphylococcal prosthetic joint infections treated with debridement and retention of the prosthesis. This study is the largest randomized controlled study on this subject. No statistical significant advantage by adding rifampin to the antimicrobial medication is shown.”