Metal hypersensitivity in total knee arthroplasty

Metals used in total knee arthroplasty cause hypersensitivity reactions in some patients. These reactions are known to be immune-mediated and are more likely to affect individuals with pre-existing metal sensitivity, but their mechanism is not fully known. It is difficult to predict pre-operatively whether a patient will be affected and there is no reliable investigation to guide implant choice. There appears to be little value in screening all patients for metal sensitivity before implantation as various studies have shown no significant difference in outcomes or failure rates post TKA in patients with history of metal sensitivity. However, the existing assessment tools are not specific enough to identify subtle problems with potential metal sensitivity association. Symptoms of hypersensitivity reactions following total knee arthroplasty are often non-specific and difficult to differentiate from other acute presentations following total knee arthroplasty, for example infection. Metal hypersensitivity reactions are often a diagnosis of exclusion, and for this reason they are most likely under-diagnosed and under-reported. Management is controversial but periprosthetic hypersensitivity reactions will often ultimately require revision if no other cause is found. Metal debris are a concern in total hip arthroplasty and could represent another cause of metal-related pathology in total knee arthroplasty. Non-metallic materials are currently in development which may represent a preventative solution for metal hypersensitivity reactions in total knee arthroplasty, potentially also addressing additional concerns around the use of metallic implants such as the high density and thermal conductivity of the material in comparison with the replaced tissue

Direct numerical simulation of turbulent flow over a rough surface based on a surface scan

Typical engineering rough surfaces show only limited resemblance to the artificially constructed rough surfaces that have been the basis of most previous fundamental research on turbulent flow over rough walls. In this article flow past an irregular rough surface is investigated, based on a scan of a rough graphite surface that serves as a typical example for an irregular rough surface found in engineering applications. The scanned map of surface height versus lateral coordinates is filtered in Fourier space to remove features on very small scales and to create a smoothly varying periodic representation of the surface. The surface is used as a no-slip boundary in direct numerical simulations of turbulent channel flow. For the resolution of the irregular boundary an iterative embedded boundary method is employed. The effects of the surface filtering on the turbulent flow are investigated by studying a series of surfaces with decreasing level of filtering. Mean flow, Reynolds stress and dispersive stress profiles show good agreement once a sufficiently large number of Fourier modes are retained. However, significant differences are observed if only the largest surface features are resolved. Strongly filtered surfaces give rise to a higher mean-flow velocity and to a higher variation of the streamwise velocity in the roughness layer compared with weakly filtered surfaces. In contrast, for the weakly filtered surfaces the mean flow is reversed over most of the lower part of the roughness sublayer and higher levels of dispersive shear stress are found

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SIGLEAvailable from British Library Document Supply Centre-DSC:m00/11571 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Gemeinsame Betrachtung von Kanalnetz und Klaeranlage zur Minimierung der Gesamtemissionen. Teil: Kanalnetz Abschlussbericht

SIGLEAvailable from TIB Hannover: F97B938 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Validation of a model-based measurement of the minimum insert thickness of knee prostheses A RETRIEVAL STUDY

Imaging- and therapeutic targets in neoplastic and musculoskeletal inflammatory diseas

Does Ion Release Differ Between Hip Resurfacing and Metal-on-metal THA?

Modern metal-on-metal hip resurfacing was introduced as a bone-preserving method of joint reconstruction for young and active patients; however, the large diameter of the bearing surfaces is of concern for potential increased metal ion release. We hypothesized there were no differences in serum concentrations of chromium, cobalt, and molybdenum between patients who had metal-on-metal hip resurfacing (Group A; average head diameter, 48 mm; median followup, 24 months) and patients who had 28-mm metal-on-metal THA (Group B; median followup, 25 months). Serum concentrations also were compared with concentrations in healthy subjects. We identified no differences in ion levels between Groups A and B. A distinction was made according to gender. Women showed a higher chromium release in Group A whereas men had a higher cobalt release in Group B. Values obtained from Group A were higher than those of the control subjects. Our data suggest metal-on-metal bearings for THA should not be rejected because of concern regarding potential increased metal ion release; however, patients with elevated ion levels, even without loosening or toxicity, could be at higher risk and should be followed up periodically

Erneuerbare Energie und Minderung der Emission von Treibhausgasen durch moderne Verfahren der Abwasser- und Schlammbehandlung auf kleinen und mittleren Klaeranlagen Abschlussbericht

In terms of the 'Kreislaufwirtschaftsgesetz' accruing sludge of WWTP has to be minimized. Furthermore should the utilisation of matter and energy be preferred opposite to disposal. In the framework of this project the use of sludge for energy production at small and medium sized WWTP's has been investigated and the reduction of green house gas emission has been evaluated. For significant process steps within the wastewater and sludge treatment resulting potential of green house gas emission as been estimated. As one option in reducing this emission the anaerobe sludge stabilisation implicating use of bio gas can be applied. In this regard the mesophil and thermophil sludge digestion has been compared and evaluated. Emphasis has been put on the investigation with regard to amount of bio gas produced, degradation of organic matter, strain of process water and dewatering. Representative results have been derived from measures over a period of two years of a pilot plant using sludge of small and medium sized WWTP's. The investigation considered two-stage system i.e. mesophil/mesophil as well as thermophil/mesophil operation mode. Furthermore has the change from mesophil to thermophil operation mode been investigated for large WWTP's. For the pilot plant estimation for dimensioning have been developed considering significant aspects present at small and medium sized WWTP's. Finally has the anaerobe sludge stabilisation been economically evaluated allowing conclusions for similar systems in practice. (orig.)SIGLEAvailable from TIB Hannover: F04B1651+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany)DEGerman

Fasting therapy - an expert panel update of the 2002 consensus guidelines

Fasting for medical purpose (fasting therapy) has a long tradition in Europe and is established as a defined therapeutic approach in specialized fasting hospitals or within clinical departments for integrative medicine. In 2002, the first guidelines for fasting therapy were published following an expert consensus conference; here we present a revised update elaborated by an expert panel. Historical aspects and definitions, indications, methods, forms, and accompanying procedures of fasting as well as safety and quality criteria of fasting interventions are described. Fasting has shown beneficial effects in various chronic diseases with highest level of evidence for rheumatic diseases. Preliminary clinical and observational data and recently revealed mechanisms of fasting and caloric restriction indicate beneficial effects of fasting also in other chronic conditions such as metabolic diseases, pain syndromes, hypertension, chronic inflammatory diseases, atopic diseases, and psychosomatic disorders. Fasting can also be applied for preventing diseases in healthy subjects. In order to guarantee successful use of fasting and to ensure adherence of all safety and quality standards it is mandatory that all interventions during fasting are guided/accompanied by physicians/therapists trained and certified in fasting therapy