Background Undiagnosed low-grade prosthetic joint infections (PJI) are recognized as an important reason for early failure of presumably aseptic revisions. Preoperatively administered antimicrobial prophylaxis reduces the incidence of PJI but it may reduce the sensitivity of microbiologic periprosthetic tissue cultures and consequently increase the incidence of undiagnosed septic prosthetic joint failures, which can lead to catastrophic serial revisions. Questions/purposes We wished to determine whether administration of preoperative antibiotics decreases the likelihood of diagnosing PJI in patients undergoing revision hip or knee arthroplasty in whom infection is suspected. Methods We prospectively enrolled and evaluated 40 patients (29 with THAs and 11 with TKAs) who met the following inclusion criteria: older than 18 years, with suspected PJI of unknown cause, undergoing surgical revision. After arthrotomy, three tissue samples were obtained for microbiologic analysis and diagnosis, and antimicrobial prophylaxis (cefazolin 2 g intravenously) then was administered. Later during the procedure, but before débridement and irrigation, the second set of three tissue samples was obtained from the same surgical area and was cultured. Tissue concentration of prophylactic antibiotic was verified with the second set of samples. A positive culture result was defined as one or more positive cultures (growth on agar at or before 14 days). We then compared the yield on the microbiologic cultures obtained before administration of antibiotics with the yield on the cultures obtained after antibiotics were administered. An a Each author certifies that he or she, or a member of his or her immediate family, has no funding or commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research 1 editors and board members are on file with the publication and can be viewed on request. Clinical Orthopaedics and Related Research 1 neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDA approval status, of any drug or device before clinical use. Each author certifies that his or her institution approved the human protocol for this investigation, and that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained. This work was performed at the Valdoltra Orthopaedic Hospital, Ankaran, Slovenia. priori analysis was performed; with the numbers available, we had 98% power to detect a difference in diagnostic sensitivity of 33%. Results With the numbers available, we found no difference in the likelihood that an infection would be diagnosed between the samples obtained before and after administration of antimicrobial prophylaxis...

A simple, fast, and cost-effective LC-MS/MS method for quantification of rifampicin in human plasma was developed and fully validated. The plasma samples containing rifampicin and isotopically labelled internal standard rifampicin D8, were cleaned up using a Captiva ND Lipids filtration plate. Chromatographic separation was achieved on an 1290 Infinity liquid chromatograph coupled to 6460 Triple Quadrupole operated in positive mode on a core-shell Kinetex C18 column (50 × 2.1 mm, 2.6 μm) by gradient elution using 0.1% formic acid in water and acetonitrile as a mobile phase. The proposed method is the fastest method published by now, both in terms of sample preparation (approximately one minute per sample) and chromatographic analysis (total run time 2.4 min). Another key benefit is the outstanding sensitivity and wide analytical range (5-40000 μg/L) with good linearity, accuracy, and precision. The method showed almost complete recovery (92%) and absence of any significant matrix effect as demonstrated by uniform responses from QC samples prepared in blood plasma from 6 volunteers (RSD <5%). The proposed method was successfully applied to rifampicin quantification in 340 patients’ plasma samples, thus demonstrating its suitability for both therapeutic drug monitoring and pharmacokinetic analysis.

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Background After elective tibial osteotomy patients are considered at high risk of venous thromboembolism (VTE) due to prolonged immobilisation. Routine pharmacological thromboprophylaxis for these patients is widely adopted in clinical practice despite a lack of evidence. There is no consistent agreement on the optimal agent or the duration of prophylaxis. While the newer oral anticoagulants seem to offer significant benefits compared to low molecular weight heparins (LMWH), there is still uncertainty about their safety profile, mainly bleeding rates and surgical wound complications. Purpose The aim of our study was to estimate the effect of rivaroxaban on surgical wound complications compared to the commonly used LMWH dalteparin sodium in patients after elective tibial osteotomy. Materials and methods We conducted a blinded prospective observational study between January 2012 and July 2012. Consecutive adult patients were included after elective tibial osteotomy. Patients with CLCR < 30 ml/min, liver disease Child class B or C or abnormal coagulation profile were excluded. All patients received a routine perioperative prophylactic antibiotic (1 g cefazolin IV after the induction of anaesthesia) and postoperative analgesia (15 mg piritramide IV every 6 h and paracetamol 1 g IV every 8 h). None of them had concomitant treatment. Thromboprophylaxis with was assigned to each patient included. The method of thromboprophylaxis was determined by the anaesthesiologist’s preference and consisted of either dalteparin 5000 IU SC. or rivaroxaban 10 mg p.o., beginning within 6–8 h after the surgery and continued every 24 h until full mobilisation. We monitored prolonged wound secretion and wound healing delay more than 14 days after the surgery. Results 30 patients were included in the study; 8 female and 22 male, average age 38.2 years (18–55). 22 (74%) patients were given dalteparin, to (27%) rivaroxaban. The incidence of prolonged wound secretion and wound healing delay was 4.5% (1 patient) in the dalteparin group, while 25% (2 patients) in rivaroxaban group, but the difference was not significant (p = 0.099). Conclusions Data suggest that the use of rivaroxaban for thromboprophylaxis in tibial osteotomy could be connected to higher incidence of prolonged wound discharge and wound healing compared to dalteparin. The difference was not statistically significant, maybe because of too small a number of patients included in the study. Additional studies are required to clarify the potential effect of rivaroxaban on surgical wound complications after elective tibial osteotomy. No conflict of interest.

Spondylodiscitis with/without neurologic impairment is a serious infection, predominantly occurring in high-risk patients. Campylobacter fetus caused spondylodiscitis is very rare. Evidence-based therapeutic concepts for lumbar spondylodiscitis are lacking. A 64-year-old high-risk woman underwent decompression with instrumented lumbar fusion. Six months after index surgery, she developed pyelonephritis, which deteriorated to sepsis and presentation of cauda equina syndrome. She underwent urgent revision with decompression, debridement, and instrumentation removal, and received long-term antibiotics. Culture grew Campylobacter fetus, previously not reported as a cause of spondylodiscitis after elective instrumented lumbar fusion. Emergent debridement and removal of instrumentation, with 2 months of targeted intravenous antibiotics followed by 6 weeks of oral antibiotics led to complete spondylodiscitis resolution. Prompt diagnostics and targeted antibiotic treatment are paramount when dealing with spinal infections, particularly in patients with rare causative pathogens like Campylobacter fetus. Concomitant neurological complications may require emergent surgical management in the case of cauda equina syndrome.