In the diagnosis of prosthetic joint infection (PJI), many biomarkers have shown a sound performance in terms of accuracy, sensitivity and specificity. In this study we aimed to test the frequently used serum biomarkers C-reactive Protein (CRP), Fibrinogen, Leukocytes, Interleukin-6 (IL-6), Interferon alpha (IF-alpha) and Procalcitonin (PCT) regarding these qualities. Following that, the optimal multi-biomarker combination was calculated to further improve the diagnostic performance. 124 knee or hip revision arthroplasty procedures were prospectively investigated focusing on preoperative serum blood levels of CRP, Fibrinogen, Leukocytes, IL-6, IF-alpha and PCT. The presence of PJI was determined by a blinded researcher. Logistic regression with lasso-regularization was used for the biomarkers and all their ratios. Following cross-validation on a training sample set to get optimal performance estimates, we performed the final model on a test set (25% of all samples).Aim
Method
This study was performed to investigate the concentration of silver ions release up to a time of 9 weeks as well as the antimicrobial activity of silver sulfate and Nano-silver mixed bone cement on Candida albicans, in expectation of a new way of therapy in manner of a time limited application – a silverions releasing bone cement spacer. Two different kinds of silver products were used and mixed with polymethylmetacrylate (PMMA, De Puy) bone cement:
Nano-silver with a particle size of 5–50 nm and active surface of 4 m2/ g. (Nanonet Styria, Austria) Silver sulfate in a finely powdered form (Fisher, GB) Concentrations of 0.1%, 0.5%, 1% and 5% of the Nano-silver and the silver-salt by weight were mixed with the dry powder portion of the cement. To test the silver-ions release from the silver-containing bone cement two models of elution, a static model and a dynamic model were created. To test the antifungal effectiveness of the various concentrations of Ag-PMMA the bone cement samples were tested by agar diffusion assay. With respect to minimal inhibition concentration (MIC) the sample containing 0.5 % silver sulfate showed required concentration at the dynamic elution model but none of the nano-silver samples did. In static elution model we measured the maximum concentration of 466.5 µg/l at the 0.5 % silver sulfate sample which is much below the toxic concentration. Agar diffusion assay showed no zone of inhibition from Nano-silver samples. In contrast, silver sulfate containing samples showed a zone of inhibition exactly growing, depending on the samples silver sulfate concentration. According to results, silver sulfate addition to PMMA might be another approach in treatment of candida associated periprosthetic joint infection.
