Polymerase Chain Reaction Detection of Bacterial Infection in Total Knee Arthroplasty

Synovial fluid aspirates from 50 patients with symptoms after total knee arthroplasty were analyzed by means of the polymerase chain reaction for the presence of bacterial deoxyribonucleic acid indicative of infection. Synovial fluid specimens were processed using a rapid bacterial lysis and extraction protocol, subjected to polymerase chain reaction amplification using universal bacterial primers, and polymerase chain reaction products analyzed by deoxyribonucleic acid hybridization methodology. Polymerase chain reaction testing on preoperative aspirates yielded 32 specimens positive for bacterial infection. Standard microbiologic culturing assays performed on the same samples gave 6 positive bacterial infection tests; intraoperative culturing identified 9 additional infected specimens. All culture positive specimens were polymerase chain reaction positive; in contrast, there were no false polymerase chain reaction positives in 21 negative control specimens obtained from aseptic joints. The synovial fluid processing protocol and polymerase chain reaction analysis can be performed with a minimum of time and may provide greater sensitivity than standard diagnostic tests. In view of the high incidence of false negative test results from standard microbiologic assays of synovial fluid specimens, the use of molecular biology based bacterial detection methodology should provide an additional, or alternative, assay to identify infected patient specimens.