Comparison of bacterial results from conventional cultures of the periprosthetic membrane and the synovial or pseudocapsule during hip revision arthroplasty.

INTRODUCTION

Bacterial identification is essential to diagnose and treat a revision for prosthetic loosening of an infected hip. The purpose of this study was to determine whether conventional cultures from the periprosthetic membrane are superior to synovial/pseudocapsule samples in the diagnosis of infection in hip revision arthroplasty.

MATERIALS AND METHODS

We performed a prospective study including all hip revisions from October 2009 to October of 2011. Once the implants were removed and prior to the administration of the antibiotic prophylaxis, six periprosthetic samples from different sites were sent to the laboratory for culturing: two periprosthetic fluid samples, two solid material (synovial/pseudocapsule) samples and two swabs. Once the six samples were taken, antibiotic prophylaxis was administered and just as the implant was removed, two more solid samples of the periprosthetic membrane were obtained.

RESULTS

Of a total of 86 hip revision surgeries, 22 were considered septic revisions postoperatively, of which 16 resulted in positive cultures. Of these 16 revisions, 14 obtained the same microbiologic diagnostic when considering either the synovial/pseudocapsule culture results or the solid membrane sample.

CONCLUSIONS

We conclude that the membrane sample for a conventional culture is not superior to the synovial/pseudocapsule sample in detecting microorganisms.