Periprosthetic joint infections (PJI), caused by pathogens, for which no biofilm-active antibiotics are available, are often referred to as difficult-to-treat (DTT). It is unclear whether DTT PJI has worse outcome due to unavailability of biofilm-active antibiotics. We evaluated the outcome of DTT and non-DTT PJI managed according to a standardized treatment regimen. Patients with hip and knee PJI from 2013 to 2015 were prospectively included and followed-up for ≥2 years. DTT PJI was defined as growth of microorganism(s) resistant to biofilm-active antibiotics. The Kaplan-Meier survival analysis was used to compare the probability of infection-free survival between DTT and non-DTT PJI.Background
Methods
The incidence of hematogenous periprosthetic joint infections (hPJI) is unknown and the cases probably largely underreported. Unrecognized and untreated primary infectious foci may cause continuous bacteremia, further spread of microorganisms and thus treatment failure or relapse of infection. This study aimed at improving knowledge about primary foci and microbiological characteristics of this entity to establish preventive measures and improve diagnostic and therapeutic strategies to counteract hPJI. We retrospectively analysed all consecutive patients with hPJI, who were treated at our institution from January 2010 until December 2016. Diagnosis of PJI was established if 1 of the following criteria applied:(i) macroscopic purulence, (ii) presence of sinus tract, (iii) positive cytology of joint aspirate (>2000 leukocytes/μl or >70% granulocytes), (iv) significant microbial growth in synovial fluid, periprosthetic tissue or sonication culture of retrieved prosthesis components, (v) positive histopathology. PJI was classified as hematogenous if the following criteria were fulfilled additionally: (1) onset of symptoms more than 1 month after arthroplasty AND (2) i) isolation of the same organism in blood cultures OR ii) evidence of a distant infectious focus consistent with the pathogen.Aim
Method
The uncertainty of the biological effects of wear and corrosion from Metal-on-metal (MoM) implants has initiated a debate on their safety and use. Generally, the release of wear particles from MoM hip implants can clinically manifest in aseptic osteolysis. In our study, the effect of MoM-wear particles and particle originated Co and Cr ions on mesenchymal stromal cells (MSCs) was investigated [1]. The lead hypotheses were that (1) dissociated Co and Cr, originated from MoM-wear particles, accumulate in the bone marrow and (2) apparently impair the osteogenic function of local MSCs. This impairment could be one element contributing to the manifestation of periprosthetic osteolyses. The study was approved by the local ethical committee (EA1/194/13); all donors gave written informed consent. Blood (B), Synovial fluid (SF) periprosthetic tissue (PT) and bone marrow (BM) were collected from patients with at least one osteolytic lesion, undergoing a revision of a MoM hip implant. Patients undergoing primary THA served as controls. Metal wear particles were isolated from PT by enzymatic digestion and their size and shape characterized by transmission electron microscopy (TEM). Local and systemic levels of Co and Cr were analyzed by graphite furnace atomic absorption spectroscopy. MoM-MSCs and control-MSCs were isolated from BM for INTRODUCTION
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