Development of a dosing-adjustment tool for fluoroquinolones in osteoarticular infections: The Fluo-pop study.

Fluoroquinolones efficacy depend on both the drug exposure and the level of drug resistance of the bacteria responsible for the infection. Specifically for the Staphylococcus species, which is the microorganism mainly involved in osteoarticular infections (OAI), in-vitro data reported that an AUC/MIC ratio above 115 h maximizes drug efficacy. However, data on OAI patients are lacking and a simple approach to access AUCs is still a clinical issue. We conducted a prospective, single-center study in 30 OAI patients hospitalized in the Rennes University Hospital to model ofloxacin pharmacokinetics and to define a limited sampling strategy (LSS) suitable for ofloxacin and levofloxacin treatments. Modeling was conducted with the Monolix software. The final model was externally validated using levofloxacin data. Monte-Carlo simulations were used to evaluate the probability of target attainment (PTA) of different dosing regimens. Two hundred and ninety-seven (297) ofloxacin concentrations were available for the pharmacokinetic modeling. Ofloxacin pharmacokinetics was best described using a bicompartmental model with a first order elimination, and a transit compartment model absorption. CKD-EPI and sex explained half of ofloxacin pharmacokinetic variability. For LSS, the 0, 1 h and 3 h sampling scheme resulted in the best approach both for BID and TID dosages (R2 adjusted = 91.1% and 95.0%, outliers = 4.8% and 5.0%, respectively). PTA allows choosing the best drug and dosage according to various hypotheses. A simple 3-sample protocol (pre-dose, 1 h after intake and 3 h after intake) to estimate ofloxacin and levofloxacin AUC allows optimal drug dosage for the treatment of osteoarticular infections.

Does performing outpatient total hip arthroplasty contribute to early complications and readmissions? Retrospective case-control study of 50 patients.

INTRODUCTION: Advances in anesthesia and surgical practices have allowed total hip arthroplasty to be performed as an outpatient procedure. The aim of this study was to demonstrate its feasibility in a selected population compared to a group of inpatients by analyzing the cumulative length of hospital stay, complications and readmissions. PATIENTS AND METHODS: This was a retrospective, single-surgeon study of continuous adult patients between October 2016 and May 2018 who underwent primary total hip arthroplasty (THA) and were eligible to undergo this procedure either as an inpatient or outpatient based on their health and comprehension level. Two groups of patients were set up. The outpatient group was given a preoperative treatment education session. The same anesthesia protocol and surgical technique was used in both groups. RESULTS: Fifty outpatients were compared to 77 inpatients. In the outpatient group, the patients were significantly younger, had a greater walking distance and were predominantly male. The two groups were comparable in terms of functional and medical criteria. The mean cumulative hospital stay was 1.2days in the outpatient group with one discharge failure because of nausea and vomiting, versus 5.1days in the inpatient group (p<0.0001). There were three complications in each group (p=1.00). There were three readmissions in the outpatient group and four in the inpatient group (p=1.00) that were of similar length (p=0.86). There was no difference in the mean number of additional office visits over this period between the two groups. CONCLUSION: Outpatient THA procedures can be done reliably and safely in France in a carefully selected population without increasing the complication rate or readmission rate. Expanding this practice requires implementing specific anesthesia and surgery protocols, along with close perioperative monitoring to help manage risk. LEVEL OF EVIDENCE: IV (retrospective cohort study).

Ultrasound in Total Hip Replacement: Value of Anterior Acetabular Cup Visibility and Contact With the Iliopsoas Tendon.

OBJECTIVES: To assess visibility of the acetabular cup in total hip replacement and to determine the value of direct and indirect signs of iliopsoas impingement syndrome with ultrasound. METHODS: Ultrasound examinations were performed by a single operator in 17 patients with iliopsoas impingement syndrome and 48 control patients. Cup visibility, contact between the cup and psoas tendon, and the presence of indirect signs of iliopsoas impingement syndrome were investigated in all patients. When the acetabular cup was visible, its size and position in relation to the psoas tendon were recorded. RESULTS: Anterior cup visibility (P = .03), contact with the psoas tendon (P < .001), psoas tendinopathy (P = .02), and iliopsoas bursitis (P < .001) were significantly associated with iliopsoas impingement syndrome, the latter reported with specificity of 100%. In the sagittal plane at the level of the psoas tendon, a maximum sagittal length of greater than 5 mm and a posteroanterior cup shift of 3 mm or greater yielded respective sensitivities of 82% and 59% and specificities of 81% and 100%. CONCLUSIONS: When iliopsoas impingement syndrome is clinically suspected, the presence of iliopsoas bursitis or a posteroanterior cup shift of greater than 3 mm under the psoas tendon serve to confirm the diagnosis. In the absence of these conditions, a therapeutic test may be necessary because of the incomplete, albeit high, specificity of other signs.

Use of MALDI-TOF mass spectrometry after liquid enrichment (BD Bactec™) for rapid diagnosis of bone and joint infections.

Advantages of MALDI-TOF MS (MS) were evaluated for diagnosis of bone and joint infections after enrichment of synovial fluid (SF) or crushed osteoarticular samples (CSs). MS was performed after enrichment of SF or crushed osteoarticular samples CS (n = 108) in both aerobic and anaerobic vials. Extraction was performed on 113 vials (SF: n = 47; CS: n = 66), using the Sepsityper® kit prior identification by MS. The performances of MS, score and reproducibility results on bacterial colonies from blood agar and on pellets after enrichment in vials, were compared. MS analysis of the vial resulted in correct identification of bacteria at a species and genus level (80.5% and 92% of cases, respectively). The reproducibility was superior for aerobic Gram-positive bacteria (Staphylococci and Gram-positive bacilli: 100% colonies), as compared to aerobic Gram-negative bacilli (89.7%), anaerobes (83.3%) and Streptococcus/Enterococcus (58.8%). MS performance was significantly better for staphylococci than for streptococci on all identification parameters. For polymicrobial cultures, identification (score>1.5) of two species by MS was acceptable in 92.8% of cases. Use of MS on enrichment pellets of bone samples is an accurate, rapid and robust method for bacterial identification of clinical isolates from osteoarticular infections, except for streptococci, whose identification to species level remains difficult.

Is tibial cut navigation alone sufficient in medial unicompartmental knee arthroplasty? Continuous series of fifty nine procedures.

PURPOSE: Our purpose was to assess medial unicompartmental knee arthroplasty with navigation alone for the tibial cut and limb alignment. We hypothesised that this technique could be used routinely in practice. METHODS: Outcome measures were tibial cut orientation and residual varus. Six-month post-operative radiographs of 59 knees were assessed. RESULTS: Tibial cut orientation was within 2° of planned in 70.2 and 76.3 % of knees in the coronal and sagittal planes, respectively (49.1 % in both), within 4° in 91.2 and 91.5 %, respectively (82.5 % in both). All coronal-plane errors were in varus. Excessive planed tibial slope was at risk of excessive varus of the tibial cut. The hip-knee-ankle angle was ≤179° in 81.4 % and the mechanical axis through Kennedy Zone 2 in 59.3 % of knees. Risk factors for inadequate varus were pre-operative hip-knee-ankle angle >176° and strictly articular varus. CONCLUSIONS: Our results are not as good as previously reported with this technique, but taking into account the factors of failure identified, we could enhance the results.

Aspergillus arthritis and organ transplantation.

We report a case of a kidney and pancreas transplanted patient, hospitalized for septic hip arthritis. The whole diagnostic work-up including synovial and bone biopsies remained negative. After inefficient empirical anti-bacterial antibiotic treatment, femoral head resection was performed and tissue analysis revealed Aspergillus fumigatus hyphae. Treatment with voriconazole along with hip replacement led to complete recovery. However, drug interaction between immunosuppressive and anti-fungal drugs was complicated by cellular acute graft rejection. Aspergillus fumigatus arthritis is an uncommon and serious infection that should be evoked especially in the case of resistance to anti-microbial antibiotics and/or an atypical clinical picture.