Abstract
Introduction
Despite the lack of data regarding the diagnostic validity of synovial aspiration in Girdlestone hips a Girdlestone-aspiration is often performed before reimplantation to detect a possible persistence of infection during two staged revision total hip arthroplasty (THA). The aim of this study was to assess the diagnostic performance of the synovial aspiration in Girdlestone hips, without a PMMA-Spacer, for the detection of infection persistence prior to THA reimplantation.
Methods
Seventy four patients undergoing a two staged revision THA surgery between 2006 and 2013 were included in this retrospective cohort study. Both synovial cultures and CRP values were acquired before explantation of the THA and of the Girdlestone hip before reimplantation. An antibiotic holiday of 14 days was observed prior to synovial aspiration.
A PJI was defined according to the following criteria: intraarticular presence of pus or a sinus tract, a periprosthetic membrane indicative of infection in the histological analysis, or a positive microbiological isolation in a minimum of two samples.
Results
The initial synovial aspiration of the THA, before the endoprosthetic explantation, achieved a sensitivity of merely 68% and a specificity of 50% for the detection of periprosthetic joint infection. The determination of CRP-values surpassed both the sensitivity and specificity values achieved by the synovial aspiration with 95% and 91%, respectively.
The synovial aspiration of the Girdlestone hip was only able to produce four positive bacterial cultures. Three of these four positive Girdlestone aspirations were interpreted as legitimate bacterial isolations, while one was classified as a contamination. These four positive bacterial isolations resulted in a sensitivity of 13% and a specificity of 98% for synovial aspiration of the Girdlestone hip. The determination of the CRP-values in Girdlestone hips, prior to THA-reimplantation, achieved a sensitivity of 95% and a specificity of 20%.
Conclusion
Our data shows that the synovial aspiration of a Girdlestone hip is of inferior diagnostic validity and poses the risk of contamination. Therefore, we advise against the synovial aspiration of Girdlestone hips during a two stage THA revision, since this can neither reliably confirm nor exclude a persistence of infection.
