Adding a glycopeptide to the cement spacer in 2-stage exchange procedures for periprosthetic joint infections reduces the rate of positive cultures during re-implantation and is associated with a lower failure rate due to coagulase-negative staphylococci, according to research results published in Clinical Infectious Diseases.

A multicenter study retrospectively examined 2-stage exchange procedures performed from 2000 to 2015 at 2 academic centers in order to define the role of antibiotics in the cement space with regard to re-implantation cultures and subsequent failure.

Patients in whom no cultures were obtained, patients without data on cement spacers, and patients with culture-negative periprosthetic joint infections were excluded from the study, leaving 344 patients cases to be analyzed.

The rate of positive cultures during re-implantation for cement spacers containing a glycopeptide compared to those containing monotherapy with an aminoglycoside was 9.5% vs 21.7%; respectively (P =.008). The difference was attributed to reductions in coagulase-negative staphylococci, which were 17% in patients receiving glycopeptide treated spacers vs 2% in patients receiving monotherapy (P <.001). In patients with positive cultures at re-implantation the failure rate was greater than 2-fold higher: 40% compared to 15.8% when cultures were negative (P <.001). A gylcopeptide in the cement spacer was associated with a lower failure rate due to coagulase-negative staphylococci: 2.5% with glycopeptide vs 13.3% without (P <.001). This, however, was not the case for the overall failure rate with cement spacers with or without a glycopeptide, which was 18% vs 23%, respectively (P =.3).

The data reported here may suffer from selection bias due to the retrospective nature of the study, which complicates interpretation. Further, variation between the 2 centers and small changes over time to culturing techniques and prophylactic regimens meant the exact influence of these on positive cultures during re-implantation could not be evaluated. In addition, detailed information on factors such as previous surgeries, quality of bone-stock, and antibiotic treatment was not collected and these may have contributed to or served as further risk factors for poor outcomes.

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The investigators concluded that high infection rates during 2-stage exchange procedures both during re-implantation and follow-up require improved treatment strategies. They also stated that routinely adding a glycopeptide to the cement spacer can achieve a reduction in positive cultures, which in turn may also reduce failure rates due to coagulase-negative staphylococci.  

Reference

Wouthuyzen-Bakker M, Kheir MM, Moya I, et al. Failure after two-stage exchange arthroplasty for treatment of periprosthetic joint infection: the role of antibiotics in the cement spacer [published online October 3 2018]. Clin Infect Dis. doi:10.1093/cid/ciy851