Microbiological culture of intraoperative periprosthetic tissue samples (IPTS) is one of the main criteria in diagnosing prosthetic joint infections (PJI) as stated by different guidelines. The current techniques are labor-intensive, prone for contamination and show low sensitivity. The aim of this study was to evaluate the added value of beadmill processing of IPTS and culturing in blood culture bottles (BCBs) over the conventional method of standard agar and broth alone. We conducted a single-center prospective study from May 2017 to January 2018 at the GZA Hospitals, a secondary care hospital (1012 beds) in Antwerp, Belgium. IPTS from patients undergoing revision arthroplasty were consecutively processed. Each IPTS was aseptically divided in two equal parts: one was processed by direct inoculation on agar and in broths (non-homogenized method); the other was transferred in a sterile vial with saline solution and glass beads (EOLabs), homogenized using a mechanic cell disruptor for 30s (Disruptor genie, Scientific Industries), 2mL of the suspension was inoculated in (an)aerobic BCBs, agar plates and broths (homogenized method). Agar plates were incubated for 4d; broths and BCBs in BacT/Alert (bioMerieux) for 14d. Micro-organisms were identified using MALDI-TOF MS (Bruker). Sensitivity (Se) and specificity (Sp) were calculated against the IDSA definition of PJI for different culture sets: non-homogenized and agar/broth; homogenized processing and agar/broth, agar/broth/BCB, agar/BCB. Ethics committee approved the study.Aim
Method
Highly cross-linked polyethylene (XLPE) has been introduced in total hip arthroplasty in an effort to reduce polyethylene wear and the associated periprohetic osteolysis. Cross-linking is a procedure in which irradiation and subsequent heating stabilize the internal structure of PE. Most of the conventional PE’s used, are gamma irradiated in air or an inert environment with a dose level of no more than 25 to 50 kGy. By irradiating PE at a higher dose, optimally around 95–100 kGy, a definite reduction in wear rate has been achieved. History already provided us some mixed in vivo results regarding altered PE. Therefore, present time surgeons are cautious when it comes down to using a new PE. Some short follow up in vivo studies already suggested reduced wear rates with XLPE in comparison to conventional PE. Our aim was to demonstrate these reduced wear rates in a 2-dimensional head penetration model using the DICOMeasure™ computerized edge detection method (GreyStone, France) and to perform a clinical comparison of both groups using the Harris Hip Score and SF-36 questionnaire. Sixty hips with a Trilogy XLPE liner (Zimmer Co.) were age and BMI matched with a control group of twenty conventional Trilogy PE liners (Zimmer Co.). No differences in clinical performance were seen, but a statistically significant reduction of 67% in steady state wear rate was observed in the XLPE group. It is clear that, due to the reduction and stabilization of free radicals in polyethylene, a reduction in annual wear can be achieved.