Removal of infected cemented hinge knee prostheses using extended femoral and tibial osteotomies: Six cases

SummaryExtended femoral and tibial osteotomies were performed to remove infected cemented hinged knee prostheses in five patients (six knees) with a mean age of 72 years (44–85) and a history of multiple knee surgeries. A tibial osteotomy was used to mobilise the distal quadriceps insertion and to release the tibial extension. The femoral component was extracted by downward traction and its cement mantle was cleared through an anterior osteotomy (n=4) or via the distal approach (n=2). The bone flaps were re-approximated by wire cerclage over articulating acrylic spacers. Mean time to re-implantation of a new knee prosthesis was 11 months (6–24). Revision prostheses with cement fixation restricted to the epiphyseal-metaphyseal region were used. Infection recurred in two cases at 16 and 4 months after the prosthetic re-implantation, and was managed by joint fusion for one and irrigation/lavage for the other, respectively. At last follow-up after a mean of 53 months, the mean Parker score was 4±2, the mean IKS knee score was 66±25 (28–93), and the mean IKS function score was 7±16 (0–40). This technique facilitates the removal of infected cemented components of hinge prostheses and of the cement mantle, most notably in the absence of loosening, without compromising re-implantation of a new knee prosthesis

Extraspinal sciatica revealing late metastatic disease from parotid carcinoma

Sciatica is a clinical symptom usually caused by a disk herniation and less often by other conditions such as tumors, infections, or inflammatory diseases. We report the case of a woman in whom sciatica led to the identification of a large pelvic metastasis from a carcinoma of the parotid gland

Réduire ou ralentir la fibrillation auriculaire : est-ce la bonne question en 2010 ?

RésuméPourquoi et comment traiter la fibrillation atriale ? Cette question a paru simple pendant de nombreuses années : la fibrillation atriale, trouble du rythme cardiaque, doit être traitée par des médicaments anti-arythmiques, tant qu’ils peuvent être efficaces. Les effets secondaires de ces médicaments, comme le bénéfice fréquemment apporté par un simple traitement bradycardisant a amené à discuter il y a une dizaine d’années deux stratégies thérapeutiques, réduire ou ralentir. Mais ce choix largement mis en avant dans les précédentes recommandations thérapeutiques, apparaît aujourd’hui réducteur. En 2010 on peut sans doute proposer deux objectifs thérapeutiques, traiter les symptômes et traiter le risque cardiovasculaire associée à la fibrillation. La gêne symptomatique entraînée par l’arythmie doit être toujours évaluée chez nos patients, volontiers selon la classification récente EHRA. Parallèlement la fibrillation fait partie du continuum cardiovasculaire, et constitue un marqueur de risque supplémentaire : il apparaît certain que le contrôle de ce risque supplémentaire associé à la fibrillation ne dépend pas uniquement du traitement de l’arythmie proprement dite.SummaryWhy and how to treat atrial fibrillation? This question seemed simple for many years: atrial fibrillation, a cardiac arrhythmia, should be treated with antiarrhythmic drugs, as long as they can be effective. Side effects of these drugs, as good benefit often provided by a simple bradycardic treatment led to discuss it some 10 years ago 2 therapeutic strategies: rhythm control or rate control. But this choice widely highlighted in the previous guidelines, now seems simplistic. In 2010 we can probably offer two therapeutic goals, treat symptoms and treat cardiovascular risk associated with atrial fibrillation. The discomfort caused by symptomatic arrhythmia should always be assessed in our patients, as by the recent EHRA classification. Meanwhile fibrillation is part of the cardiovascular continuum, and is a marker of an additional risk: it appears certain that the control of this additional risk does not depend solely on the treatment of the arrhythmia itself

Les effets pro-arythmiques des médicaments

RésuméLes effets pro-arythmiques des médicaments sont fréquents et graves, et sont associés à une surmortalité non négligeable. La polymédication augmente le nombre d’effets indésirables et d’interactions graves voire mortelles. Certains sont facilement évitables. Cependant, au-delà de l’allongement de l’intervalle QT, d’autres mécanismes peuvent avoir un rôle majeur comme les dysfonctions du RyR2, responsable d’arythmie calcium-dépendantes par surcharge calcique intracellulaire, avec apparition de post-dépolarisations tardives, sans modifications de l’intervalle QT. Les bloqueurs des canaux sodiques sont également un problème sérieux de part le risque de démasquer ou d’aggraver une dysfonction du canal sodique chez des patients atteints de syndrome de Brugada asymptomatique ou non. Leur dépistage à un stade précoce du développement des médicaments peut avoir un intérêt majeur.SummaryThe cardiac safety of new and marketed drugs is a major concern for public authorities, patients, physicians as well as pharmaceutical companies. Letal adverse drug reactions are indeed a leading cause of death worldwide and increase at a greater rate than the increase in total hospital admission. The increasing use of polypharmacy in current clinical practice is also associated to a growing number of side effects and interactions leading to fatal adverse events. Measurement of the QT interval is an established, albeit incomplete, approach to assess the proarrhythmic risk of a drug. Ventricular arrhythmia (VA) can be caused by a QT-prolonging drug inducing abnormal repolarization of the action potential (AP) of ventricular cardiomyocytes. Emerging evidence, derived from recent understanding of these mechanisms and of similar mechanisms reported for heart failure (HF), suggest that diastolic Ca2+ leak from the sarcoplasmic reticulum (SR) related to RyR2 dysfunction can induce Ca2+ dependent arrhythmia. In this report, we review mechanisms underlying drug-induced arrhythmogenic effects and Ca2+ dependent arrhythmia, and, for the latter, we discuss some of the issues associated to worsening of cardiac arrhythmias

Belgian shipwrecks: hotspots for marine biodiversity

Hard bottom substrates at sea allow the development of communities that are often rich in terms of species diversity. Non-biogenic structures such as shipwrecks are an integral part of these substrates, even if they have an anthropogenic origin and the species assemblages they harbor could be for that reason qualified as 'exotic'. There are 200 recent shipwrecks on the Belgian Continental Shelf (BCS), which represent a large fraction of the hard substrate available locally; their presence has an additional interest if we know that the major part of the English Channel and Southern Bight of the North Sea consists almost exclusively of soft sediments. Five shipwrecks on the BCS will be studied in order to assess the meio- and macrofaunal diversity using direct observations and scuba sampling techniques. The soft sediments close to shipwrecks will also be studied to serve as model for areas relatively undisturbed by fisheries (untrawled). Added to this, the influence of shipwrecks on local hydrodynamics and sediment transport will favor the colonization by fragile epibenthic species and as a consequence increase habitat complexity. For each site, standard abiotic parameters and current vectors will be measured and modeled. The information will be centralized in a database and disseminated through a web site devoted to the biodiversity of the BCS. The results will be relevant to the management of the BCS; the anthropogenic hard substrates of shipwrecks can serve as a model for what will happen with the installation of offshore windmills. A brochure will increase public awareness of the importance of marine diversity, and increase public support for marine protected areas

Nouvelles méthodes d’intégration pour traiter la plasticité en X-FEM

La méthode d’intégration utilisée classiquement en X-FEM fait dépendre la position des points d’intégration de la position de la fissure, ce qui convient difficilement à l’étude de la propagation d’une fissure dans un milieu plastifié. En effet, des étapes de projection de champs sont alors nécessaires. Afin de s’en affranchir, cette contribution propose deux approches alternatives. La première s’appuie sur les schémas d’intégration standards tandis que la seconde propose de différencier les points d’intégration des points où le comportement est évalué. Les méthodes proposées se limitent aux cas des interfaces

Belgian shipwreck: hotspots for marine biodiversity BEWREMABI: final report

The main aim of the project is to document the fauna found on five shipwrecks in the Belgian part of the North Sea (map). While we have a fairly good understanding of the fauna of soft bottoms of our part of the North Sea, the fauna of these artificial hard substrates is largely unknown. Study of these habitats will allow us to understand species distribution patterns, and allow us to predict which species to expect on other artificial hard substrates, such as sokkels of wind mills. It is a two year research project carried out in the framework of the SPSD-II research action of the Belgian Federal Science Policy Office

Publisher’s Note: “Dispersion calibration for the National Ignition Facility electron–positron–proton spectrometers for intense laser matter interactions” [Rev. Sci. Instrum. 92, 033516 (2021)] (Rev. Sci. Instrum. 92, 059902 (2021)

Electron-positron pairs, produced in intense laser-solid interactions, are diagnosed using magnetic spectrometers with image plates, such as the National Ignition Facility (NIF) Electron Positron Proton Spectrometers (EPPS). Although modeling can help infer the quantitative value, the accuracy of the models needs to be verified to ensure measurement quality. The dispersion of low-energy electrons and positrons may be affected by fringe magnetic fields near the entrance of the EPPS. We have calibrated the EPPS with six electron beams from a Siemens Oncor linear accelerator (linac) ranging in energy from $2.7$--$15.2$ $\mathrm{MeV}$ as they enter the spectrometer. A Geant4 TOPAS Monte-Carlo simulation was set up to match depth dose curves and lateral profiles measured in water at $100$ $\mathrm{cm}$ source-surface distance. An accurate relationship was established between the bending magnet current setting and the energy of the electron beam at the exit window. The simulations and measurements were used to determine the energy distributions of the six electron beams at the EPPS slit. Analysis of the scanned image plates together with the determined energy distribution arriving in the spectrometer provide improved dispersion curves for the EPPS.Comment: Published in Review of Scientific Instruments, 5 pages, 3 figures, This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishin