The relationship between microbiology results in the second of a two-stage exchange procedure using cement spacers and the outcome after revision total joint replacement for infection

Abstract

Patients with infected arthroplasties are normally treated with a two-stage exchange procedure using polymethylmethacrylate bone cement spacers impregnated with antibiotics. However, spacers may act as a foreign body to which micro-organisms may adhere and grow. In this study it was hypothesised that subclinical infection may be diagnosed with sonication of the surface biofilm of the spacer. The aims were to assess the presence of subclinical infection through sonication of the spacer at the time of a second-stage procedure, and to determine the relationship between subclinical infection and the clinical outcome. Of 55 patients studied, 11 (20%) were diagnosed with subclinical infection. At a mean follow-up of 12 months (interquartile range 6 to 18), clinical failure was found in 18 (32.7%) patients. Of the patients previously diagnosed with subclinical infection, 63% (7 of 11) had failed compared with 25% (11 of 44) of those without subclinical infection (odds ratio 5.25, 95% confidence interval 1.29 to 21.4, p = 0.021). Sonication of the biofilm of the surface of the spacer is useful in order to exclude subclinical infection and therefore contributes to improving the outcome after two-stage procedures.

Sonication of Antibiotic Spacers Predicts Failure during Two-stage Revision for Prosthetic Knee and Hip Infections

“…Our results are consistent with those reported by Sorli et al [20] who described antibiotic spacer sonication results for a group of 55 patients who underwent two-stage revision surgery for deep infection of hip, knee, or shoulder hardware. Patients in that study were followed for a mean of only 1 year.…”

“…The process of implant sonication is relatively simple, can be performed in less than 10 minutes at most microbiology laboratories, and procures viable microorganisms for growth on culture media [21]. A couple studies have documented an increased sensitivity in detection of periprosthetic joint infection compared with customary intraoperative periprosthetic tissue cultures [20,21]. Sonication techniques have been shown to increase the culture sensitivities for patients who have received antibiotic treatment during the previous 2 weeks [21].…”

Two stage revision hip arthroplasty in periprosthetic joint infection. Comparison study: with or without the use of a spacer

“…One possible reason for this is that the spacer is a foreign body and thus may encourage colonization by bacteria. In some studies, biofilm has been found on the spacer removed from the hip [13][14][15].…”

Prosthetic Joint Infection

“…One study evaluated 55 patients undergoing a two-stage arthroplasty exchange for primarily hip or knee PJI and found a higher rate of clinical failure at 1 year in those with "subclinical infection" at the time of their second-stage procedure (330). Subclinical infection was defined as either a positive sonicate fluid culture from the spacer or two or more positive tissue specimens at the second-stage procedure.…”