Comportamiento del polietileno en un simulador de cadera

Se presentan los resultados del comportamiento friccional de cinco diferentes combinaciones de cabezas protésicas femorales y polietileno acetabular, investigadas en un simulador de cadera. Las cabezas femorales de aleaciones de Cr-Co-Mo, Cr-Co-Mo con implantación iónica y de cerámica de zirconia, se articularon con cotilos de polietileno de ultra-alto-peso molecular y se sometieron a tres millones de ciclos de marcha cada uno, utilizando un simulador de cadera de cinco estaciones. El desgaste de los cotilos protésicos, evaluado por mediciones gravimétricas demostró que cuando el espesor de polietileno era de 10,9 mm el desgaste producido por cabezas de Cr-Co-Mo de 28 mm era de 0,14 mm/año y de 0,09 mm/año si la cabeza utilizada era de 28 mm de aleación de Cr-Co- Mo con implantación iónica. Cuando el espesor del acetábulo era de 7 mm el desgaste ocasionado por cabezas de cerámica de zirconia de 28 mm fue de 0,04 mm/año; sin embargo si tenía espesor 10,9 mm y las cabezas de cerámica de zirconia eran de 28 y 32 mm, no aparecía desgaste alguno. Estos resultados indican que el diámetro de la cabeza de cerámica de 28 y 32 mm, parece no tener importancia alguna, pero sí la tiene el que el espesor del acetábulo protésico sea menor de 10 mm.Ultra high molecular weight polyethylene (UHMWPE) metal backed acetabular cups were articulated against Cr-Co-Mo alloy, ion implanted Cr-Co-Mo and zirconia ceramic femoral heads in a five station hip joint simulator, running three tests of three millions walking cycles with each one of the five different head-cup combinations. The wear rate of the acetabular cups was measured gravimetrically. When the thickness of the cup was 10.9 mm, the mean wear rate against 28 mm diameter Cr-Co-Mo femoral heads was 0.14 mm/year, and 0.09 mm/year 'when the cup was articulated against 28 mm ion implanted Cr-Co-Mo femoral heads. When the thickness of the cup was 7 mm the mean wear rate was 0.04 mm/year against 28 mm zirconia heads. The results indicate that significant reduction in the wear of the UHMWPE cup can be achieved when zirconia femoral head is used and that the diameter of the zirconia femoral head, 28 vs 32 mm, seems unimportant as wear factor. A cup thickness below 10 mm may result disadvantageous

Estallido de la cabeza de cerámica en 1 prótesis total de cadera cementada

Se describen las características clínicas y quirúrgicas de 1 caso de estallido de la cabeza de cerámica en 1 artroplastia total de cadera cementada tipo Weller. A los 6 años y 2 meses de su implante requirió nueva intervención quirúrgica para sustituir el componente dañado. Describimos las posibles causas de esta complicación en base a la literatura revisada. El interés del caso estriba en la rareza de su presentación y en la conservación de la prótesis sustituyendo solamente el núcleo cefálico dañado.The clinical and surgical characteristics of one case of breakage of the ceramic head in a Weller cemented hip arthroplasty is described. The patient needed revision surgery six years and two months after the primary arthroplasty in order to replace the demaged component of the implant. The possible reasons of this complication, according to a literature review, are discussed. The interest of this clinical case is the rare of its presentation, its cause and the surgical solution that allow preservation of the prosthesis, doing exclusively the replacement of the damaged part of the implant

An application of a hybrid intelligent system for diagnosing primary headaches

[Abstract] (1) Background: Modern medicine generates a great deal of information that stored in medical databases. Simultaneously, extracting useful knowledge and making scientific decisions for diagnosis and treatment of diseases becomes increasingly necessary. Headache disorders are the most prevalent of all the neurological conditions. Headaches have not only medical but also great socioeconomic significance. The aim of this research is to develop an intelligent system for diagnosing primary headache disorders. (2) Methods: This research applied various mathematical, statistical and artificial intelligence techniques, among which the most important are: Calinski-Harabasz index, Analytical Hierarchy Process, and Weighted Fuzzy C-means Clustering Algorithm. These methods, techniques and methodologies are used to create a hybrid intelligent system for diagnosing primary headache disorders. The proposed intelligent diagnostic system is tested with original real-world data set with different metrics. (3) Results: First at all, nine of 20 attributes – features from International Headache Society (IHS) criteria are selected, and then only five most important attributes from IHS criteria are selected. The calculation result based on the Calinski–Harabasz index value (178) for the optimal number of clusters is three, and they present three classes of headaches: (i) migraine, (ii) tension-type headaches (TTHs), and (iii) other primary headaches (OPHs). The proposed hybrid intelligent system shows the following quality metrics: Accuracy 75%; Precision 67% for migraine, 74% for TTHs, 86% for OPHs, and Average Precision 77%; Recall 86% for migraine, 73% for TTHs, 67% for OPHs, Average Recall 75%; F1 score 75% for migraine, 74% for TTHs, 75% for OPHs, and Average F1 score 75%. (4) Conclusions: The hybrid intelligent system presents qualitative and respectable experimental results. The implementation of existing diagnostics systems and the development of new diagnostics systems in medicine is necessary in order to help physicians make quality diagnosis and decide the best treatments for the patients.Ministerio de Ciencia e Innovación; MINECO-TIN2017-84804-RGobierno del Principado de Asturias; FCGRUPIN-IDI/2018/000226Serbia. Ministry of Education, Science and Technological Development; 451-03-68/2020-14/20015

Design and Optimization of Capacitated Supply Chain Networks Including Quality Measures

This paper presents (1) a novel capacitated model for supply chain network design which considers manufacturing, distribution, and quality costs (named SCND-COQ model) and (2) five combinatorial optimization methods, based on nonlinear optimization, heuristic, and metaheuristic approaches, which are used to solve realistic instances of practical size. The SCND-COQ model is a mixed-integer nonlinear problem which can be used at a strategic planning level to design a supply chain network that maximizes the total profit subject to meeting an overall quality level of the final product at minimum costs. The SCND-COQ model computes the quality-related costs for the whole supply chain network considering the interdependencies among business entities. The effectiveness of the proposed solution approaches is shown using numerical experiments. These methods allow solving more realistic (capacitated) supply chain network design problems including quality-related costs (inspections, rework, opportunity costs, and others) within a reasonable computational time

La prótesis de cadera con recubrimiento de vidrio Primeros resultados con 2 años de evolución

El presente trabajo analiza los primeros resultados clínicos y radiográficos de un estudio con la prótesis de cadera no cementada con recubrimiento «de vidrio» a nivel metafísario (prótesis CRM). La casuística comprende 80 artroplastias totales implantadas desde 1991 a 1994 con un seguimiento mínimo de 2 años. La evolución clínica, valorada según el sistema de Harris modificado, ha sido satisfactoria en el 90% de los enfermos. La observación radiográfica ha mostrado buena fijación y orientación de los componentes femorales en 72 casos. La conclusión de este análisis preliminar permite apreciar que el recubrimiento protésico con cerámica de vidrio supone un mecanismo de seguridad en la fijación primaria y secundaria de la prótesis de cadera.This work analizes the first clinical and radiological results of a cementless hip prosthesis with glass coating at metaphyseal level (CRM prosthesis). A total of 80 arthroplasties implanted since may 1991 to 1994 were studied with a two year follow-up. The clinical assesment was done by the modified Harris score, being satisfactory in 90% of the patients. The radiological study demonstrated good fixation and orientation of the prosthetic compounds in 72 cases. The prosthetic model studied provides a security mechanism both for primary and secondary fixation of the femoral stem and acetabular cup

Fall Detection Analysis Using a Real Fall Dataset

International Conference on Soft Computing Models in Industrial and Environmental Applications (13th. 2018. San Sebastián