An intramedullary nail is a trauma treatment device used for fracture fixation of long bones. These devices are subject to failure, including lag screw cut-out and failure at the lag screw insertion hole from high stress concentrations in that region. Clinical developments for such devices are frequently based on a trial and error method, which often results in failure before improvement. However, the finite element method can be used for the development of trauma treatment devices, and their interaction with bone, by providing a large data set at a relatively low cost. Also, parameters can be changed to assess the relative benefits of one device to another. A novel finite element model has been developed that can be used for the analysis of intramedullary nails inserted into long bones. A commercially available finite element package, ANSYS, has been used to implement the modelling strategy. The finite element modelling technique has been applied to fractures of the proximal femur, but the model is generic, and can be developed to deal with any form of intramedullary device where contact between the bone and implant is important. The finite element strategy can be used in pre-clinical trials to test a new device, or for the design optimisation of existing devices. The finite element model consists of the device surrounded by a thin layer of bone, which forms a 'base' model component that is re-usable. This 'base' component can be mathematically connected to any long bone model, forming an integrated implant and bone construct. The construct can be used to assess which device is best suited to a particular fracture, for example. Contact elements have been used to allow stresses to develop as contact is achieved within the implant and bone construct. Pre-assignment of contact points is not required. Verification of the finite element model is achieved by comparison to available data from experiments carried out on constructs of bone and device that use intramedullary femoral nails. In this thesis the finite element model has been applied to two areas of proximal femoral nailing. The finite element model is used to analyse the distal end of a Gamma nail, and shows that analyses that do not consider contact may not lead to accurate predictions of stresses. The model has been developed for using configurations with one and two distal locking screws. The most distal locking screw is more critical under axial loading, and the more proximal screw is more important for bending loads. The use of 'softer' screws distributes the load more evenly between them. The finite element model has been used to investigate the mechanical environment of a fracture callus for a femoral neck fracture, and a subtrochanteric fracture. The use of one and two lag screws, fracture gap size and material properties of the nail have been investigated for a stiffening callus. Results show that the use of two lag screws for a neck fracture provides a more rigid support at the early stages of fracture healing, and minimises stress-shielding once the callus has healed. For subtrochanteric fractures there is a critical point at which the fracture callus is able to carry any load. A Titanium nail significantly reduces the peak stress at the lag screw insertion hole, and titanium lag screws share the load more evenly between them. Each two-lag-screw configuration used transfers a similar load into the fracture callus. A configuration using a larger lag screw above a smaller has a significantly higher stress at the upper lag screw insertion hole. Critically, the load shared between two lag screws changes as the fracture callus stiffens and an assessment should be made at different stages of fracture healing to optimise the use of a device.

The function of skeletal adaptation to mechanical load is to adjust the amount and distribution of bone tissue (geometry); such that stresses experienced within the bone are kept within certain physiological limits and fractures are prevented. Genetic, environmental or hormonal factors may cause heterogeneity in this adaptive response, altering geometry and consequently fragility. The purpose of this thesis was to explore the skeletal response to load in vivo, by evaluating stress at the hip under three different conditions: FRACTURE (Study 1), DIABETES (Study 2) and ESTROGEN deficiency (STUDY 3). We studied women 25 years of age or older who participated in the Canadian Multicentre Osteoporosis Study and had available Hip Structure Analysis (HSA) data from baseline dual energy x-ray absorptiometry (DXA) scans. Women were categorized according to fracture status (fracture or no fracture), diabetes status (diabetes or no diabetes) and estrogen use (current users or never users). We computed stress (megapascals=MPa) at the infero-medial margin of the femoral neck in a one-legged iii stance using a 2-D engineering beam analysis. We used linear regression to determine associations between femoral neck stress and each categorical variable. Study 1 (n=2168) demonstrated higher stresses in postmenopausal women with fractures compared to women without fractures (10.57 ± 2.19 vs. 10.30 ± 2.03 MPa; p=0.0031). Study 2 (n=3665) demonstrated higher stresses in women with Type 2 Diabetes Mellitus compared to non-diabetic women (10.98 ± 2.33 vs. 10.57 ± 2.20 MPa; p=0.0194). Study 3 (n=2447) demonstrated higher stresses in postmenopausal women not on estrogen than in premenopausal women (10.66 ± 2.14 vs. 10.09 ± 2.01 MPa; p<0.0001), but no differences in stresses between postmenopausal women on estrogen and premenopausal women (10.16 ± 2.00 vs. 10.09 ± 2.01 MPa; p=0.6102). Since stress is an indicator of underlying geometry, and geometry should be adapted to prevalent loads, higher stress indicates weaker geometry and suggests an impaired modeling response in these three conditions. Compromised modeling has important clinical implications in terms of treatment selection, as individuals with reduced load sensitivity may respond best to metabolic agents that would improve modeling responses to load stimuli.

The function of skeletal adaptation to mechanical load is to adjust the amount and distribution of bone tissue (geometry); such that stresses experienced within the bone are kept within certain physiological limits and fractures are prevented. Genetic, environmental or hormonal factors may cause heterogeneity in this adaptive response, altering geometry and consequently fragility. The purpose of this thesis was to explore the skeletal response to load in vivo, by evaluating stress at the hip under three different conditions: FRACTURE (Study 1), DIABETES (Study 2) and ESTROGEN deficiency (STUDY 3). We studied women 25 years of age or older who participated in the Canadian Multicentre Osteoporosis Study and had available Hip Structure Analysis (HSA) data from baseline dual energy x-ray absorptiometry (DXA) scans. Women were categorized according to fracture status (fracture or no fracture), diabetes status (diabetes or no diabetes) and estrogen use (current users or never users). We computed stress (megapascals=MPa) at the infero-medial margin of the femoral neck in a one-legged iii stance using a 2-D engineering beam analysis. We used linear regression to determine associations between femoral neck stress and each categorical variable. Study 1 (n=2168) demonstrated higher stresses in postmenopausal women with fractures compared to women without fractures (10.57 ± 2.19 vs. 10.30 ± 2.03 MPa; p=0.0031). Study 2 (n=3665) demonstrated higher stresses in women with Type 2 Diabetes Mellitus compared to non-diabetic women (10.98 ± 2.33 vs. 10.57 ± 2.20 MPa; p=0.0194). Study 3 (n=2447) demonstrated higher stresses in postmenopausal women not on estrogen than in premenopausal women (10.66 ± 2.14 vs. 10.09 ± 2.01 MPa; p<0.0001), but no differences in stresses between postmenopausal women on estrogen and premenopausal women (10.16 ± 2.00 vs. 10.09 ± 2.01 MPa; p=0.6102). Since stress is an indicator of underlying geometry, and geometry should be adapted to prevalent loads, higher stress indicates weaker geometry and suggests an impaired modeling response in these three conditions. Compromised modeling has important clinical implications in terms of treatment selection, as individuals with reduced load sensitivity may respond best to metabolic agents that would improve modeling responses to load stimuli.

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde. Programa de Pós-graduação em Saúde Pública / Made available in DSpace on 2012-10-23T03:06:15Z (GMT). No. of bitstreams: 1 245044.pdf: 467222 bytes, checksum: 03fe9301dbf435cc1d60f711c9cea9c2 (MD5) / Introdução: Pesquisas têm demonstrado uma forte associação entre quedas, fraturas e demência. O presente estudo tem como objetivo avaliar as funções cognitivas de uma população de idosos internados por fratura proximal do fêmur decorrente de queda. Metodologia: Foi realizado um estudo de caso-controle não-pareado, com 151 casos e 206 controles em idosos com 60 anos ou mais, na cidade de Porto Alegre (RS). Foram utilizadas as escalas Clinical Dementia Rating (CDR) e Avaliação das Atividades da Vida Diária - Índice de Katz. Resultados: A idade avançada, o sexo feminino, as doenças do sistema osteomuscular, a pontuação total na CDR de 0,5, dois e três foram fatores de risco para quedas seguidas de fratura proximal do fêmur. Os indivíduos com CDR total de dois e três apresentaram 4,33 vezes mais chances de cair e fraturar o fêmur, comparados aos sujeitos sem déficit cognitivo. Considerações finais: Os estágios moderados e graves da demência impõem mais risco para quedas e fraturas graves em idosos. Introduction: Researches have shown a strong relationship between falls, fractures and dementia. The present study intent to avaliate the cognitive functions in an old population hospitalized in an orthopedic public hospital located in Porto Alegre to treat proximal femural fractures associated to fall. Methodology: To develop an unpareated case-control including 151 cases and 206 controls, in aged patients over 60 years. In an attempt to investigate cognitive deficit the Clinical Dementia Rating (CDR) and the Evaluation of the Activities of Daily Life had been used, the Katz index. Results: It was identified risk factors for falls associated to proximal femural fractures the advanced age, the female patients, the osteomuscular diseases, the total CDR score above 0,5, two and three. The individuals with a total CDR score two or three presented 4,33 times more chance to fracture their femur during a fall in comparation to a normal patients. Final Considerations: The moderate and severe cases of dementia present a serious risk for fall followed by fractures.

Made available in DSpace on 2014-06-11T19:35:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-04-22Bitstream added on 2014-06-13T18:46:42Z : No. of bitstreams: 1 avila_mag_dr_botfm.pdf: 578730 bytes, checksum: 87ba56e152682f55a7de09d714857502 (MD5) / Quedas em idosos devem ser consideradas evento sentinela na vida dos mesmos e, como consequência, têm-se as fraturas de fêmur proximal, evento que influi diretamente na vida do binômio idoso-cuidador familiar. Têm etiologia multicausal e podem ser atribuídas a fatores extrínsecos (ambiente, tipo de moradia, renda mensal e fatores culturais) e intrínsecos (faixa etária mais elevada, redução da função dos sistemas que compõem o controle postural, doenças, transtornos cognitivos e comportamentais, incapacidade em manter ou para recuperar o equilíbrio e não realização de atividades de fortalecimento muscular). Analisar a produção científica acerca da influência do cuidador sobre a recuperação da independência funcional de idosos em pós-operatório de cirurgia de fêmur proximal. Estudar a relação entre equilíbrio e independência funcional e a relação entre os incentivos (movimentação, autocuidado e lazer) e a independência funcional desses idosos. Estudar a relação entre conhecimento sobre a prevenção de quedas e o emprego do mesmo no cotidiano. Utilizou-se de pesquisa integrativa da literatura para alcançar o primeiro objetivo e, no segundo, de pesquisa epidemiológica transversal analítica, realizada de novembro de 2011 a outubro 2012. Considerando que a influência do cuidador na recuperação da independência funcional de idosos é desconhecida, utilizou-se uma prevalência de 50%. Como no ano de 2010 foram realizadas 1.526 cirurgias ortopédicas, correção para a população finita aplicada ao tamanho amostral encontrou um mínimo de 90 sujeitos. Foram incluídos no estudo idosos (≥ 60 anos) submetidos à cirurgia para correção de fratura de fêmur proximal, em decorrência de queda de baixa energia e recebida autorização médica de deambular há pelo menos um mês, assim como seus cuidadores informais. Os idosos eram 67,4% do sexo feminino,... / Falls in elderly people should be considered sentinel events in their lives. Consequences include proximal femoral fractures, events that directly influence the lives of the elderly and their family caregivers. Their causes are multiple and can be attributed to extrinsic (environment, housing type, monthly income and cultural factors) and intrinsic (more advanced age range, functional reduction in postural control systems, illnesses, cognitive and behavioral disorders, incapacity to maintain or recover balance and non-accomplishment of muscle strengthening activities) factors. To investigate scientific production about the caregivers’ influence on the recovery of functional independence in elderly people after a proximal femoral surgery. To study the relation between balance and functional independence and the relation between incentives (movement, self-care and leisure) and these elderly people’s functional independence. To study the relation between knowledge on falls prevention and its use in daily life. An integrative literature review was used to reach the first objective. To achieve the second, an analytic cross-sectional epidemiological research was carried out between November 2011 and October 2012. As the caregivers’ influence on the recovery of elderly people’s functional independence is unknown, the prevalence rate was set at 50%. Considering that 1,526 orthopedic surgeries were accomplished in 2010, a correction for the finite population applied to the sample size resulted in a minimum of 90 subjects. Inclusion criteria were: elderly people (≥ 60 years) Submitted to proximal femoral fracture surgery, due to low-energy falls, who had received medical authorization to walk at least one month earlier, as well as their informal caregivers. Among the elderly patients, 67.3% were female, 46.1% aged≥ 80 years and 57.3% submitted to osteosynthesis. The ...(Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:35:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-08-26Bitstream added on 2014-06-13T18:46:43Z : No. of bitstreams: 1 000734574.pdf: 1421299 bytes, checksum: d57cbab065709a779a78d1479aa2310a (MD5) / Trata-se de pesquisa na abordagem qualitativa conduzida na cidade de Londrina, Paraná, Brasil, para compreender a experiência do idoso pós-cirúrgico com fratura de fêmur e, propor um modelo teórico que a representasse. A saturação teórica se configurou mediante a análise da nona entrevista do tipo não diretiva. Estas foram audiogravadas, transcritas na íntegra e analisadas segundo os passos da Teoria Fundamentada nos Dados, de julho a novembro de 2011. Emergiram quatro subprocessos: surpreendendo-se com a fratura; movendo-se entre a segurança e a insegurança na hospitalização; deparando-se com a iniquidade da rede de atenção do idoso dependente e ao cuidador familiar; superando no domicílio a perda da independência apoiado na família, na religiosidade e na reminiscência. Do realinhamento dos componentes desses subprocessos originou a categoria central e modelo teórico, denominado - entre a segurança e a insegurança no restabelecimento da independência funcional do idoso, após fratura de fêmur: família, religiosidade e reminiscência como apoios para a superação. Ao analisar o modelo teórico à luz do Interacionismo Simbólico verificou-se a suscetibilidade desse idoso à queda seguida de fratura, associada a invisibilidade mental desses eventos, enquanto não se materializaram. Pode-se levantar, também, os símbolos que indicaram a vulnerabilidade desse idoso no processo de reabilitação, perpassando desde o atendimento pré-hospitalar, hospitalar e domiciliar. Esses símbolos foram: morosidade de serviços de urgência e emergência em diagnosticar a fratura, mediante a demanda de usuários que perpassavam a capacidade de atendimento desses serviços e o despreparo de profissionais na avaliação clínica, agravada pela precarização de serviços de apoio radiodiagnósticos; espera por avaliações que dependiam da disponibilidade de outros profissionais e da realização... / This is a qualitative approach in research conducted in the city of Londrina, Paraná, Brazil, to understand the experience of the elderly with post-surgical hip fracture, and proposes a theoretical model that represents it. The theoretical saturation was configured by analyzing the ninth non-directive interview type. They were audio taped, transcribed and analyzed according to the steps of the Grounded Theory, from July through November, 2011.From this analysis, four sub processes emerged: surprising himself with the fracture; moving between security and insecurity in hospitalization; encountering the iniquity of the network of care for dependent elderly and family caregivers; overcoming at home the loss of independence supported by the family, religiosity and reminiscence. Realignment of these sub-components originated the central category and theoretical model, called - between security and insecurity in restoring functional independence of the elderly after hip fracture: family, religion and reminiscence as support to overcome. By analyzing the theoretical model in the light of Symbolic Interactionism the susceptibility of the elderly fall followed by fractures was verified associated with mental invisibility of these events, while not materialized. Symbols that indicated the vulnerability of this elderly in the rehabilitation process, passing from the pre-hospital care, hospital and home can also be mentioned. They were: slow service and emergency in diagnosing the fracture upon user demand aspects that exceed the service capacity evaluation, exacerbated by precariousness of radiology support services; waiting for assessments that depended on the availability of other professionals and other examinations, as well as vacancies, concomitantly, in the Surgical Center and ICU and inputs to perform the procedure safely, impaired communication with the health care team in the ICU, lack of patience and respect for the body of the elderly ...

Made available in DSpace on 2015-06-17T19:34:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-02-26. Added 1 bitstream(s) on 2015-06-18T12:48:59Z : No. of bitstreams: 1 000834610.pdf: 293273 bytes, checksum: f51e9e2ae4c1980ea4f071c64c0122ff (MD5) / Em programas de melhoramento de frangos de corte, as aves são selecionadas principalmente para características de desempenho e carcaça, acarretando em mudanças no tamanho, forma e função dos órgãos, o que implica em alterações fisiológicas importantes durante o desenvolvimento das aves. A seleção intensa dos frangos de corte resultou em problemas locomotores, diminuição da resistência óssea dos animais e aumento da mortalidade. Com isso, técnicas de biologia molecular podem ser utilizadas na seleção assistida por marcadores com o intuito de identificar genes candidatos para auxiliar no processo de seleção de características relacionadas às desordens ósseas. Os objetivos do presente trabalho foram estimar os parâmetros genéticos para características relacionadas à integridade óssea do fêmur e peso aos 42 dias de idade e estudar as associações dos genes RUNX2 (Runt-related transcription factor 2) e TNFSF11 (Tumor necrosis fator (ligand) superfamily, member 11) com características de importância econômica em frangos de corte no intuito de fornecer suporte para o programa de melhoramento genético de aves e direcionar o processo de seleção visando a redução dos problemas relacionadas às desordens ósseas. Estimativas de parâmetros genéticos, fenotípicos e ambientais foram obtidas para características associadas à integridade óssea do fêmur e peso aos 42 dias de idade (P42) pelo método de máxima verossimilhança restrita utilizando modelo animal multicaracterística, com efeito fixo de grupo (sexo e incubação) e os efeitos aleatórios genéticos aditivos e residuais. Análises de associações genéticas entre o SNP g.57.397A>G (RUNX2) e SNP g.14.614A>G (TNFSF11) com características de desempenho, composição de carcaça, órgãos e integridade óssea do fêmur foram realizadas com o propósito de avaliar os efeitos desses polimorfismos sobre esse grupo de características, por ... / In the broiler breeding programs, the broilers are selected primarily for performance and carcass traits, resulting in changes in the size, shape and function of organs which implies important physiological changes during the development of the broilers. Intense selection of broilers resulted in locomotors problems, decreased bone strength of animals and increased mortality. Thus, molecular screening techniques began to be used in order to identify candidate genes to assist in the selection of related traits to bone disorders. The objective of this study was estimate genetic parameters for traits related to femoral integrity bone and weight at 42 days and association study of RUNX2 (Runt-related transcription factor 2) and TNFSF11 (Tumor necrosis factor (ligand) superfamily, member 11) genes with economical traits in broilers in order to provide support for the broiler breeding program and direct the selection process to reduce problems related to bone disorders. Estimates of genetic parameters were obtained for traits associated with the femur bone integrity and weight at 42 days of age by the restricted maximum likelihood method using multi-trait animal model with the fixed group effect (sex and incubation), and the random effects and additives residuals. The investigation of polymorphisms in association RUNX2 genes and TNFSF11 and the association study of polymorphisms found and their respective SNPs (Nucleotide single polymorphism) of RUNX2 genes (SNP g.57.397A>G) and TNFSF11 (SNP g.14.614A> g) with the performance, carcass composition, parts and femoral bone integrity in order to evaluate the effects of these polymorphisms about this group of traits to maximum likelihood method. We used the TT reference population database with about 1,500 broilers belonging to Embrapa Swine and Poultry Breeding Program in Concordia/SC, Brazil. Heritability coefficients estimated for weight at 42 days of age (W42) and the related traits to ...

Doctorat en kinésithérapie et réadaptation / info:eu-repo/semantics/nonPublished

We introduce a new way to accurately segment the 3D femur from pelvic CT scans. The femur is a difficult target for segmentation due to its proximity to the acetabulum, irregular shape and the varying thickness of its hardened outer shell. Atypical bone morphologies, such as the ones present in hips suffering from Femoral Acetabular Impingements (FAIs) can also provide additional challenges to segmentation. We overcome these difficulties by (a) dividing the femur into the femur head and body regions (b) analysis of the femur-head and neighbouring acetabulum’s composition (c) segmentations with two levels of detail – rough and fine contours. Segmentations of the CT volume are performed iteratively, on a slice-by-slice basis and contours are extracted using the morphological snake algorithm. Our methodology was designed to require little initialization from the user and to deftly handle the large variation in femur shapes, most notably from deformations attributed to cam-type FAIs. Our efforts are to provide physicians with a new tool that creates patient-specific and high-quality 3D femur models while requiring much less time and effort. We tested our methodology on a database of 20 CT volumes acquired at the Ottawa General Hospital during a study into FAIs. We selected 6 CT scans from the database, for a total of 12 femurs, considering wide inter-patient variations. Of the 6 patients, 4 had unilateral cam-type FAIs, 1 had a bilateral cam-type FAI and the last was from a control group. The femurs segmented with our method achieved an average volume overlap error of 2.71 ± 0.44% and an average symmetric surface distance of 0.28 ± 0.04 mm compared against the same, manually segmented femurs. These results are better than all comparable literature and accurate enough to be used to in the creation of patient-specific 3D models.

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