Currently, the most common approach for the management of a chronic PJI is a Two-Stage Replacement; because of success rates exceeding 90% when using an antibiotic impregnated cement spacer. Reliable information regarding the etiologic microorganism and its sensitivities is essential to select the antimicrobial therapy that should be used locally in the bone cement spacer during the first stage surgery as well as to select the appropriate microbiological systemic agent. Diagnostic algorithms focus to the importance of joint aspiration cultures although in the modern literature, preoperative joint aspiration has a broad range of values of sensitivity and the proportion of “dry-aspirations” is not well assessed. This low sensitivity of aspiration fluid samples in chronic-PJI is partly attributable to the fact that the majority of the microorganisms in these infections grow in biofilms attached to the implant. We have developed this biopsy technique in an effort to improve the identification rates of the causative organism. A sample is harvested through a 4 mm bone trephine and the target is the bone-prosthesis gap. We have compared the results of preoperative PIB with the results of cultures from intra-operative tissue collected during the first stage surgery. In both cases a prolonged culture protocol (10 days) in enrichment media was used. On the basis of this relation, sensitivity, specificity, positive and negative predictive values and accuracy were calculated.Aims
Materials and methods
