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Aim: In this study the accuracy of the 16S DNA polymerase chain reaction (PCR) in revision arthroplasties was compared to that of conventional bacterial culture when correlated to intraoperative histological findings. Furthermore, the influence of antibiotic treatment and different ways of collecting samples was evaluated., Method: In a prospective study we collected samples of tissues, aspiration fluids and swabs during revision arthroplasty surgery and examined them with PCR as well as conventional bacterial culturing methods. Also, we correlated these two methods with the histological findings of intraoperative tissue samples. Two independent examiners evaluated the samples according to the criteria of Mirra et al. Sensitivity, specificity, positive and negative prediction value and the accuracy were calculated for the molecular biological and culture methods. Three groups were defined to evaluate the influence of accompanying antibiotic treatment and the way of collecting the microbiological samples., Results: Nine periprosthetic infections could be detected by PCR as well as by conventional bacterial culturing. Correlated with the 25 positive histological findings this resulted in a sensitivity of 0.36, a specificity of 1.0, a negative prediction value of 0.61, a positive prediction value of 1.0 and an accuracy of 0.68 for both methods. Swabs compared to aspiration fluids and tissues samples showed the highest sensitivity with both methods. No higher sensitivity of PCR compared to conventional bacterial culturing could be observed in patients with accompanying antibiotic treatment., Conclusion: Although PCR is more rapidly available for the diagnosis of periprosthetic infection, a definite advantage of this more expensive method could not be demonstrated in view of the same low sensitivity of PCR and conventional bacterial culturing.

Aim: In this study, the accuracy of antigranulocyte scintigraphy as a diagnostic means prior to revision in infected total knee replacement was compared to that of preoperative joint aspiration and laboratory parameters. The most efficient combination of all diagnostic methods was calculated and thus a diagnostic algorithm recommended. The value of PCR was compared to commonly used techniques of microbiological culturing., Methods: Preoperative diagnostic means for infection of 50 total knee replacements in 45 patients requiring revision surgery, were retrospectively analyzed. Inclusion criteria were the intraoperative microbiological and histological verification of infection. Sensitivity, specificity, negative and positive prediction value of C-reactive protein (CRP) and leukocytes, antigranulocyte scintigraphy with (99m)Tc-labeled antibodies, and preoperative joint aspiration were calculated. Furthermore, the accuracy of the different techniques of culturing was compared to that of the polymerase chain reaction (PCR) based on the intraoperative histological findings. Two blinded examiners evaluated specimens taken intraoperatively according to the criteria of Mirra., Results: We observed a sensitivity of 1.0, a specificity of 0.82, a positive prediction value of 0.83 and a negative prediction value of 1.0 for the antigranulocyte scintigraphy. The sensitivity of preoperative joint aspiration was 0.5, the specificity 1.0, and the positive and negative prediction values were 1.0 and 0.5. Correlated to the intraoperative histological findings the accuracy of PCR and culturing was comparable. The highest accuracy was obtained for blood culture samples., Conclusion: Compared to preoperative joint aspiration the antigranulocyte scintigraphy proved to be more sensitive in the diagnosis an infected knee replacement while having a high specificity. An advantage of PCR compared to the common microbiological culturing techniques was not observed.

Aim: In the case of two-stage infect revision arthroplasties of hip and knee joint, of primary resection arthroplasties and before implantation of arthroplasties after septic arthritis the accuracy of preoperative laboratory parameters and antigranulocyte scintigraphy was analysed. Furthermore, we stained the intraoperatively taken joint synovial samples with hematoxylin-eosin and also with antibodies against human neutrophil elastase in order to investigate if immunohistological examination provides further or different information., Method: In 24 patients with intraoperative verification of infection we calculated sensitivity, specificity, positive and negative predictive values for laboratory tests, antigranulocyte scintigraphy and the most suitable combination of both. The joint synovial samples stained with antibodies against human neutrophil elastase were compared to those stained with hematoxylin-eosin according to the criteria of Mirra., Results: We observed the best results for the combination of C-reactive protein and antigranulocyte scintigraphy with a sensitivity of 1, a specificity of 0.92, a positive predictive value of 0.75 and a negative predictive value of 1. No additional or different information was observed by the immunohistological stained samples., Conclusion: Stage diagnostic using C-reactive protein and antigranulocyte scintigraphy provides accurate information to assess the status of infection before hip and knee replacement after infect revision. Additional immunohistological staining besides the routinely taken hematoxylin-eosin staining of joint synovial samples is not recommended.