Complex primary total hip arthroplasty

SummaryAlthough total hip arthroplasty is now a classic procedure that is well controlled by orthopedic surgeons, some cases remain complex. Difficulties may be due to co-morbidities: obesity, skin problems, muscular problems, a history of neurological disease or associated morphological bone deformities. Obese patients must be informed of their specific risks and a surgical approach must be used that obtains maximum exposure. Healing of incisions is not a particular problem, but adhesions must be assessed. Neurological diseases may require tenotomy and the use of implants that limit instability. Specific techniques or implants are necessary to respect hip biomechanics (offset, neck-shaft angle) in case of a large lever arm or coxa vara. In case of arthrodesis, before THA can be performed, the risk of infection must be specifically evaluated if the etiology is infection, and the strength of the gluteal muscles must be determined. Congenital hip dysplasia presents three problems: the position and coverage of the cup, placement of a specific or custom made femoral stem, with an osteotomy if necessary, and finally lowering the femoral head into the cup by freeing the soft tissues or a shortening osteotomy. Acetabular dysplasia should not be underestimated in the presence of significant bone defect (BD), and reconstruction with a bone graft can be proposed. Sequelae from acetabular fractures presents a problem of associated BD. Internal fixation hardware is rarely an obstacle but the surgical approach should take this into account. Treatment of acetabular protrusio should restore a normal center of rotation, and prevent recurrent progressive protrusion. The use of bone grafts and reinforcement rings are indispensible. Femoral deformities may be congenital or secondary to trauma or osteotomy. They must be evaluated to restore hip biomechanics that are as close to normal as possible. Fixation of implants should restore anteversion, length and the lever arm. Most problems that can make THA a difficult procedure may be anticipated with proper understanding of the case and thorough preoperative planning

Is there something of the MCT in orientationally disordered crystals ?

Molecular Dynamics simulations have been performed on the orientationally disordered crystal chloroadamantane: a model system where dynamics are almost completely controlled by rotations. A critical temperature T_c = 225 K as predicted by the Mode Coupling Theory can be clearly determined both in the alpha and beta dynamical regimes. This investigation also shows the existence of a second remarkable dynamical crossover at the temperature T_x > T_c consistent with a previous NMR and MD study [1]. This allows us to confirm clearly the existence of a 'landscape-influenced' regime occurring in the temperature range [T_c-T_x] as recently proposed [2,3].Comment: 4 pages, 5 figures, REVTEX

Avances en el manejo eficiente del olivar surbonaerense

Cinco años de vinculación entre la Cámara de Productores Olivícolas “Sur Oliva”, con sede en la cabecera del partido surbonaerense de Coronel Dorrego, el Programa Nacional de Reconversión Productiva (Cambio Rural) dependiente de la Chacra Experimental Integrada Barrow del Instituto Nacional de Tecnología Agropecuaria y las asignaturas Propiedades Edáficas y Fertilidad (módulo Física de Suelo), Fruticultura, Utilización de Residuos Orgánicos, Zoología Agrícola y Patología Vegetal del Departamento de Agronomía de la Universidad Nacional del Sur han consolidado un grupo de trabajo interdisciplinario y una vía de comunicación con el medio productivo. Se comenzó con la detección de problemáticas que originaron distintas líneas de investigación con la participación de estudiantes y graduados y el apoyo de organismos provinciales (Comisión de Investigaciones Científicas) y municipales. Luego surgieron actividades de asistencia técnica a productores y se instalaron parcelas experimentales en una de las fincas, las cuales generan conocimientos y experiencias, que también enriquecen la labor docente con la incorporación curricular de nuevos contenidos. La difusión de resultados y conclusiones se canaliza a través de revistas, jornadas y reuniones científicas, y mediante el contacto directo con integrantes del sistema productivo. También se publicó material en la revista “AgroUNS”, órgano de difusión del Departamento de Agronomía

A Giant Crater on 90 Antiope?

Mutual event observations between the two components of 90 Antiope were carried out in 2007-2008. The pole position was refined to lambda0 = 199.5+/-0.5 eg and beta0 = 39.8+/-5 deg in J2000 ecliptic coordinates, leaving intact the physical solution for the components, assimilated to two perfect Roche ellipsoids, and derived after the 2005 mutual event season (Descamps et al., 2007). Furthermore, a large-scale geological depression, located on one of the components, was introduced to better match the observed lightcurves. This vast geological feature of about 68 km in diameter, which could be postulated as a bowl-shaped impact crater, is indeed responsible of the photometric asymmetries seen on the "shoulders" of the lightcurves. The bulk density was then recomputed to 1.28+/-0.04 gcm-3 to take into account this large-scale non-convexity. This giant crater could be the aftermath of a tremendous collision of a 100-km sized proto-Antiope with another Themis family member. This statement is supported by the fact that Antiope is sufficiently porous (~50%) to survive such an impact without being wholly destroyed. This violent shock would have then imparted enough angular momentum for fissioning of proto-Antiope into two equisized bodies. We calculated that the impactor must have a diameter greater than ~17 km, for an impact velocity ranging between 1 and 4 km/s. With such a projectile, this event has a substantial 50% probability to have occurred over the age of the Themis family.Comment: 30 pages, 3 Tables, 8 Figures. Accepted for publication in Icaru

New European guidelines for the management of dyslipidaemia in cardiovascular prevention

The new guidelines from the European Atherosclerosis Society and the European Society of Cardiology include a number of updated items. In this paper, we summarize 4 of these changes that we consider to be the most pertinent. Firstly, cardiovascular risk is now stratified according to 4 (previously 2) categories: "very high risk" (patients with cardiovascular disease, patients with diabetes > 40 years old who have at least one other risk factor, patients with kidney failure, or patients in primary prevention with a SCORE value > or = 10%); "high risk" (patients in primary prevention with a SCORE value > or = 5% and or = 1% and < 5%); and "low risk" (primary prevention with SCORE < 1%). The SCORE value for patients in primary prevention is estimated using the SCORE table (calibrated for Belgium). Risk in this table may now be corrected according to HDL cholesterol level. Secondly, the therapeutic targets for each category are now more stringent: LDL cholesterol < 70 mg/dl (or reduced by at least 50%) if the risk is "very high"; < 100 mg/dl if the risk is "high"; and < 115 mg/dl if the risk is "moderate". Thirdly, for patients at "high" or "very high" risk, particularly in patients with combined dyslipidaemia, two further therapeutic targets should be considered: non-HDL cholesterol and apolipoprotein B levels. Fourthly, the follow-up of efficacy (lipid profile) and tolerance (hepatic and muscular enzymes) is described in more details so as to harmonize case management in clinical practice.Peer reviewe

Validation of an educational booklet targeted to patients candidate for total knee arthroplasty

SummaryBackgroundKnee osteoarthritis is a highly prevalent condition and the leading reason for total knee arthroplasty (TKA). No consensus exists about the optimal content of preoperative patient information and, to the best of our knowledge, no validated information document is available. Our objective here was to obtain validation by healthcare professionals and patients of an educational booklet for patients awaiting TKA.Materials and methodsThe booklet was developed and validated in six phases: systematic literature review, drafting of the first version, critical revision by a panel of experts, modification of the booklet, validation by a multidisciplinary panel of experts, and validation by two groups of patients, one composed of patients awaiting TKA and the other of patients in the immediate post-TKA period. We assessed the impact of the booklet based on knowledge and belief scores before and 2 days after receiving the booklet.ResultsCritical revision of the first draft led to changes to meet the concerns voiced by the experts. Knowledge improved only in the patient group given the booklet preoperatively (from 6/10 to 9/10, P=0.005). The booklet did not modify beliefs in either patient group.DiscussionWe used a rigorous methodology to develop and validate the contents of an educational booklet. Receiving this document before TKA resulted in improved patient knowledge but had no impact on beliefs.Level of evidenceLevel IV