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Doctoral Thesis
DOI
https://doi.org/10.11606/T.17.2020.tde-08022021-144411
Document
Author
Full name
Anderson Freitas
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
Ribeirão Preto, 2020
Supervisor
Committee
Shimano, Antonio Carlos (President)
Cliquet Junior, Alberto
Guimarães, João Antonio Matheus
Herrero, Carlos Fernando Pereira da Silva
Title in Portuguese
Análise mecânica do reforço femoral proximal com polimetilmetacrilato em forma de X (análise in vitro)
Keywords in Portuguese
Ensaio mecânico
Fratura do colo femoral
Método dos elementos finitos
Osteoporose
Polimetilmetacrilato
Abstract in Portuguese
A osteoporose é considerada um problema de saúde pública com diversas consequências negativas, sendo a principal delas a ocorrência de fratura por trauma de baixa energia do extremo proximal do fêmur. São crescentes as investigações que buscam tratamentos para reduzir a incidência desta fratura, a qual possui um alto índice de morbidade e mortalidade, ocorrida na osteoporose. O objetivo deste estudo foi investigar a influência de um método de reforço do extremo proximal do fêmur (EPF) utilizando polimetilmetacrilato (PMMA) em forma de X, em ossos sintéticos, utilizando ensaios mecânicos e o método dos elementos finitos. Foram utilizados quinze ossos sintéticos da marca SawboneTM divididos em três grupos experimentais (n=5), sendo: grupo controle (DP), que não foram submetidos a nenhum tipo de reforço, grupo perfurado sem reforço (DSX), que foram submetidos a técnica de perfuração em X mas não foram preenchidos com PMMA e o grupo reforço em X (DX), que foram submetidos a uma técnica de reforço com PMMA. Exclusivamente no grupo DX, o volume de (PMMA) e a temperatura, durante o processo de preenchimento do X, foram avaliados. No ensaio mecânico, sob as mesmas condições, simulando queda sobre o trocanter, dos três grupos, observou-se: força máxima, deslocamento, rigidez e energia absorvida. Já no método do elemento finito, foram avaliadas as tensões máxima e mínima principal observadas nas regiões dos extremos proximais dos fêmures dos diferentes grupos experimentais. A média de volume e da temperatura alcançadas durante o preenchimento do grupo DX foi de 9,8 ml e 42,54 °C. Os resultados no ensaio mecânico obtidos para todos os modelos sintéticos dos 3 grupos experimentais, foram: as médias das forças máximas: (5562,0 ± 464,8) N, (4798,0 ± 121,2) N e (7132,0 ± 206,9) N, as médias dos deslocamentos: (13,6 ± 1,45) mm, (11,1 ± 0,5) mm e (13,2 ± 0,69) mm, as médias das rigidez: (673 ± 64,34) N/mm, (636 ± 8,7) N/mm e (738 ± 17,13) N/mm e as médias das energias absortivas de (36203 ± 3819) N.mm, (27617 ± 3011) N.mm e (44762 ± 3219) N.mm, todos respectivamente para os grupos DP, DSX e DX. Valores estes que demonstraram significância estatística com uso do teste ANOVA One-way (5%) para os parâmetros de força máxima, rigidez e energia absortiva entre os grupos. Nas simulações utilizando o método do elemento finito, as tensões máximas principais foram de: 24,82 kPa; 27,26 kPa; 18,03 kPa, e as tensões mínimas principais foram de: -61,54 kPa; -68,89 kPa; -42,66 kPa. Com os resultados das propriedades mecânicas e das análises das tensões, pelo método dos elementos finitos, verificou-se importantes vantagens na utilização do reforço do EPF em X, com o PMMA, no aumento da resistência mecânica estrutural, em modelos sintéticos de fêmures com caracteristicas osteoporóticas.
Title in English
Mechanical analysis of proximal femoral reinforcement with X-shaped polymethylmethacrylate (in vitro analysis)
Keywords in English
Femoral neck fracture
Finite element method
Mechanical test
Osteoporosis
Polymethylmethacrylate
Abstract in English
Osteoporosis is considered a public health issue with several negative consequences, among which the most significant is the occurrence of low energy trauma to the proximal femoral extremity. There is an increasing number of studies looking for treatments to reduce this fracture as a high rate of morbidity and mortality occurred on osteoporosis. The objective of this study was to investigate the influence of a method for strengthening the femoral proximal extremity (FPE) using X-shaped polymethylmethacrylate (PMMA) in synthetic bones through mechanical tests and the Method Element Finite. Fifteen SawboneTM synthetic bones were used, divided into three experimental groups (n=5), as follows: the control group (DP), who were not submitted to any type of reinforcement, the perforated group without reinforcement (DSX), who were submitted to an X-shaped perforation technique but were not filled with PMMA and the X-shaped reinforcement group (DX), who were submitted to a PMMA reinforcement technique. Exclusively in the DX group, the volume of (PMMA) and the temperature during the filling process of X were evaluated. In mechanical tests under the same conditions, simulating a fall on the trochanter, of the three groups, it was observed: maximum load, displacement, stiffness and absorptive energy. In the Method Element Finite, the maximum and minimum principal tensions observed in the regions of the proximal ends of the femurs of the different experimental groups were evaluated. The average volume and temperature reached when filling the DX group was 9.8 ml and 42.54 °. The mechanical tests results obtained for all synthetic models of the 3 experimental groups, were: the average maximum loads: (5562.0 ± 464.8) N, (4798.0 ± 121.2) N and (7132.0 ± 206.9) N, displacement averages: (13.6 ± 1.45) mm, (11.1 ± 0.5) mm and (13.2 ± 0.69) mm, mean stiffness: (673 ± 64.34) N/mm, (636 ± 8.7) N/mm and (738 ± 17.13) N/mm and the mean absorptive energy of (36203 ± 3819) N.mm, (27617 ± 3011) N.mm and (44762 ± 3219) N.mm, all respectively for the DP, DSX and DX groups. Values that demonstrated statistical significance with the use of the One-way ANOVA test (5%) for the parameters of maximum load, stiffness and absorptive energy between groups. In simulations using the Method Element Finite, the main maximum stresses were: 24.82 kPa; 27.26 kPa; 18.03 kPa, and the main minimum stresses were: -61.54 kPa; -68.89 kPa; -42.66 kPa. With the results of the mechanical properties and the simulations using the Finite Element Method, important advantages were verified, the use of the X reinforcement, with the PMMA, in the increase of the structural mechanical resistance in the proximal extremity of synthetic femurs with osteoporosis properties.
 
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2021-03-24
 
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