Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

Helium identification with LHCb

The identification of helium nuclei at LHCb is achieved using a method based on measurements of ionisation losses in the silicon sensors and timing measurements in the Outer Tracker drift tubes. The background from photon conversions is reduced using the RICH detectors and an isolation requirement. The method is developed using pp collision data at √(s) = 13 TeV recorded by the LHCb experiment in the years 2016 to 2018, corresponding to an integrated luminosity of 5.5 fb-1. A total of around 105 helium and antihelium candidates are identified with negligible background contamination. The helium identification efficiency is estimated to be approximately 50% with a corresponding background rejection rate of up to O(10^12). These results demonstrate the feasibility of a rich programme of measurements of QCD and astrophysics interest involving light nuclei

Curvature-bias corrections using a pseudomass method

Momentum measurements for very high momentum charged particles, such as muons from electroweak vector boson decays, are particularly susceptible to charge-dependent curvature biases that arise from misalignments of tracking detectors. Low momentum charged particles used in alignment procedures have limited sensitivity to coherent displacements of such detectors, and therefore are unable to fully constrain these misalignments to the precision necessary for studies of electroweak physics. Additional approaches are therefore required to understand and correct for these effects. In this paper the curvature biases present at the LHCb detector are studied using the pseudomass method in proton-proton collision data recorded at centre of mass energy √(s)=13 TeV during 2016, 2017 and 2018. The biases are determined using Z→μ + μ - decays in intervals defined by the data-taking period, magnet polarity and muon direction. Correcting for these biases, which are typically at the 10-4 GeV-1 level, improves the Z→μ + μ - mass resolution by roughly 18% and eliminates several pathological trends in the kinematic-dependence of the mean dimuon invariant mass

Usefulness of color Doppler in the diagnosis of ventricular septal rupture after myocardial infarction

Ten consecutive patients with ventricular septal rupture complicating acute myocardial infarction were studied by means of Doppler echocardiography (including two-dimensional, conventional and color Doppler techniques) and bedside right heart catheterization using a Swan-Ganz catheter. One patient died before an operation could be performed. Seven critically ill patients underwent emergency cardiac surgery without preoperative cardiac catheterization, while in two patients it was also possible to undertake coronary angiography before surgery. Two-dimensional echocardiography diagnosed post-infarction ventricular septal rupture in 6 out of 10 patients. Color Doppler revealed the presence and the location of septal rupture in all 10 patients. The color Doppler diagnosis was confirmed either by surgery or necropsy. The estimates of pulmonary artery pressure, obtained by color Doppler-guided continuous wave Doppler beam, were very close to those measured by simultaneous right heart catheterization. In 3 patients, patch leakage occurred 3 days, 15 days and 1 year after the operation. Two-dimensional echocardiography revealed the patch leakage in only one of 3 patients while its location was visualized by color Doppler in all 3 patients. In one patient the color Doppler diagnosis was confirmed at necropsy. In the remaining 2 patients, a small left-to-right shunt was demonstrated by radionuclide studies. Color Doppler echocardiography is a highly sensitive and rapid technique in the diagnosis of postinfarction ventricular septal rupture. In critically ill patients it offers relevant information and may obviate the need for any invasive preoperate investigation