The effects of different levels of fluoride in drinking water on different parameters of femurs and incisors of female rats were studied. Rats and their offspring, before and after weaning, were used for the study. Mother rats received 0, 1 and 5 ppm fluoride in drinking water. After weaning, the offspring were given the following treatments: 0-0, 0-1, 0-5, 1-0, 1-1, 1-5, 5-0, 5-1 and 5-5; the first number indicating fluoride level of mother's water during mating, pregnancy and lactation and the second number indicating the fluoride level of water given to the offspring. Femurs and top and bottom incisors were collected from mother rats, 21 day old pups and 300g. body weight pups. Femurs were analysed for ash, calcium, phosphorus and fluoride content and breaking strength. Only fluoride analyses were done on incisors. Fluoride ion electrodes (Orion models 94-09 and 96-09) were used for fluoride analysis. Mother rats that received 1 and 5 ppm of fluoride showed on increase in fluoride content of teeth. There was no increase in the fluoride content of weanling rat teeth suggesting that there was no maternal transfer of fluoride to the offspring. A significant increase in fluoride content of femur and teeth of all the groups of 300g. offspring, that received 1 and 5 ppm of fluoride, was observed as compared to the control group (0-0). No significant differences in other femur parameters of 300 g. offspring were observed. Significant differences in fluoride content of femurs and incisors of 300g. rat offspring were found due to pre and post-weaning fluoride treatments. Combined pre and post-weaning fluoride administration resulted in higher fluoride content of femurs and incisors. At the levels used in this study, pre-weaning fluoride administration alone does not appear to affect the fluoride content of bone and teeth of the rat offspring, but fluoride, when given ofter weaning does contribute to the increased fluoride content of bone and teeth.

The study presented attempts to prove the concept that mechanical changes in the structure of a bone can be predicted for a specific exercise by a subject specific model created from CT data, MRI data, EMG data, and a physiologic FE model. Previous work generated a subject specific FE model of a femur via CT and MRI data as well as created a set of subject specific biomechanical muscle forces that are required to perform a single leg extension exercise. The FE model and muscle forces were implemented into a single leg extension FE code (ABAQUS) along with a specialized bone remodeling UMAT. The UMAT updated the mechanical properties of the femur via a damage-repair bone remodeling algorithm. The single leg extension FE code was verified by applying walking loads to the femur and allowing the system to equilibrate. The results were used to apply the appropriate walking loads to the final FE simulation for the single leg extension exercise. The final FE simulation included applying the single leg extension loads over a one year period and plotting the change in porosity at various regions of the femoral neck. Although only two regions were found to generate valid results, the data seemed counterintuitive to Wolff’s Law which states that bone adaptation is promoted when the material is stressed. The model was successful in creating a subject specific model that is capable of predicting changes in the mechanical properties of bone. However, in order to generate valid FE model results, further understanding of the bone remodeling process and application via a FE model is required.

found that most of these factors are directly or indirectly linked to subjects’ BMI (body mass index). Thus, from a statistical perspective, BMI could be an overall indicator of the probability of femur fracture from a sideways fall. Using a biomechanics approach coupled with statistical data we investigate this relationship with a large cohort of postmenopausal women aged 50-79 from WHI-OS (Women’s Health Initiative Observational Cohort). The cohort is divided into six sub-cohorts by BMI where each fall-related factor is examined and compared with each other. Significant differences are discovered among cohorts in terms of femur size, aBMD (areal bone mineral density), peak fall force based on kinematics, and maximum von Mises stresses induced in the proximal femur. Through a probabilistic margin of safety approach which has been recently applied to orthopedic application, we found the margin of safety predicted probability to be decreasing faster with increasing BMI and better v fitted with medical record of the identical cohort compared to that found using a deterministic risk factor approach. To promote the application in other situations, tumor damaged femur bones are examined and tested for possible stress concentration effect in terms of probability of failure. The influence of tumor lesion turned out to be size and location sensitive. The superior side of the femoral neck has the highest stress concentration effect from tumor lesion where a 4mm diameter lesion could result in a 1.7 times greater maximum von Mises stress and 2.95 times greater probability of failure.

The purpose of this study was to develop injury risk functions for dynamic bending of the human femur in the lateral-to-medial and posterior-to-anterior loading directions. A total of 45 experiments were performed on human cadaver femurs using a dynamic three-point drop test setup. All 45 tests resulted in mid-shaft femur fractures with comminuted wedge and oblique fractures as the most common fracture patterns. The reaction loads were used to develop the injury criteria given that they represent the inertially compensated bending strength of the femur that is more appropriate for dummy load cell application. In the lateral-to-medial bending tests the peak reaction bending moments were 352 ± 83 Nm. In the posterior-to-anterior bending tests the peak reaction bending moments were 348 ± 96 Nm. Regression analysis was used to identify significant parameters, and parametric survival analysis was used to estimate risk functions. Femur cross-sectional area, area moment of inertia (I), maximum distance to the neutral axis (c), I/c, occupant gender, and occupant mass are shown to be significant predictors of fracture tolerance, while no significant difference is shown for loading direction, bone mineral density, leg aspect and age. Risk functions are presented for femur cross-sectional area, I/c, and a combined occupant gender and mass. The risk function that utilizes the most highly correlated (R2 = 0.77) and significant (p = 0.0001) variable, cross-sectional area, predicts a 50 percent risk of femur fracture of 240 Nm, 395 Nm, and 562 Nm for equivalent cross-sectional area of the 5th percentile female, 50th percentile male, and 95th percentile male respectively. / Master of Science

Tez (Tıpta Uzmanlık) - Süleyman Demirel Üniversitesi, Tıp Fakültesi, Genel Cerrahi Anabilim Dalı, 2002.

Orientador: Maurício Etchebehere / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-20T07:16:01Z (GMT). No. of bitstreams: 1 Mouraria_GuilhermeGrisi_M.pdf: 1020067 bytes, checksum: 911879a0f520b1816324bfcb8b9f71d7 (MD5) Previous issue date: 2012 / Resumo: O carcinoma de mama é a neoplasia mais frequente no mundo desenvolvido e a segunda mais frequente no Brasil. O diagnóstico tardio da doença é associado frequentemente com a presença de metástases ósseas. No esqueleto apendicular, o fêmur é o local mais acometido. As lesões femorais muitas vezes levam a fratura. Fatores prognósticos na mortalidade de pacientes com metástase óssea oriundas de neoplasias em geral estão relatados na literatura. Entretanto, não há relato específico de fatores prognósticos nas pacientes com metástases de neoplasia de mama no fêmur submetidas a tratamento cirúrgico. A determinação dos fatores prognósticos em portadores de metástase óssea auxilia na decisão terapêutica para cada paciente. O objetivo do estudo foi determinar os fatores clínicos e ortopédicos relacionados à mortalidade nesta coorte de pacientes. O estudo retrospectivo incluiu quarenta e um pacientes submetidos a tratamento cirúrgico da metástase femoral. Foram analisadas as seguintes variáveis: número e local das metástases ósseas e viscerais, presença de fratura patológica no fêmur, técnica cirúrgica empregada e exames laboratoriais (hematócrito, hemoglobina, ureia e creatinina). Tais fatores foram correlacionados com a mortalidade utilizando-se o método de COX de regressão logística multivariada e também a construção de curvas de mortalidade de Kaplan Meier testada pelo método de log-rank. O tempo de seguimento médio foi de 37 meses. Houve alta prevalência de múltiplas metástases associadas a fraturas patológicas no momento do ato cirúrgico. A mortalidade foi elevada e precoce. A localização subtrocantérica e distal, a presença de fratura, presença de anemia e alteração na função renal associaram-se a maior mortalidade. O tipo de implante, o número de metástase óssea e a presença de metástase em outros órgãos não influenciaram na mortalidade. Conclui-se que as lesões metastáticas no fêmur devem ser tratadas cirurgicamente o mais rapidamente possível, independentemente do implante utilizado, para evitar a fratura / Abstract: Breast carcinoma is a common malignancy in the developed world and in Brazil. Late diagnosis of the disease is frequently associated with bone metastasis. In the appendicular skeleton, the femur is most commonly affected. The lesions often lead to femoral fractures. Prognostic factors of mortality in patients with bone metastases originating from cancers in general have been reported. However, there is no specific report of prognostic factors in relation to breast cancer metastasis in the femur surgically treated. The determination of prognostic factors in patients with bone metastasis can assist in therapeutic decisions for each patient. The aim of this study was to determine clinical and orthopedic factors related to mortality in patients with breast cancer and metastases to the femur underwent surgical treatment. This was a retrospective cohort study and included 41 patients undergoing surgical treatment of femoral metastases. We analyzed the following variables: number and location of bone metastases, visceral metastases, presence of pathological fracture, fixation method, and laboratory tests. These factors were correlated with mortality using Cox multivariate logistic regression and Kaplan-Meier curves. The average follow-up was 37 months. There was a high prevalence of multiple metastases associated with pathological fractures at the time of surgery. Mortality was high and early. Subtrochanteric location, the presence of fractures, anemia, and alterations in renal function were associated with higher mortality. The fixation method (synthesis or prosthesis / endoprosthesis), the number of bone metastases, and the presence of metastasis in other organs did not affect mortality.Breast cancer with metastasis to the femur is an advanced disease with early mortality. Clinical and orthopedic factors should be considered as soon as possible when lesions occur, regardless of the type of implant used / Mestrado / Fisiopatologia Cirúrgica / Mestre em Ciências

No description available.

The aim of the Diploma Thesis is to propose the methodology of a 3D model creation of a femoral part of a knee joint replacement. As the knee joint is the most loaded joint of the human body, the function, description and biomechanics relation is described in first part of the Thesis. The second part is focused on degenerative damage of knee joints that leads to the implantation of standard knee joint replacements. The third part deals with the construction of standard knee joint replacements and their surgery implantation. The last part of the Thesis describes the creation of an individual knee joint replacement, especially the femoral part.

published_or_final_version / abstract / Orthopaedics and Traumatology / Master / Master of Philosophy

Accurate and automatic segmentation techniques that do not require any explicit prior model have been of high interest in the medical community. We propose a fully-automatic method for segmenting the femur from 3D Computed Tomography scans, based on the graph-cut segmentation framework and the bone boundary enhancement filter analyzing second-order local structures. The presented algorithm is evaluated in large-scale experiments, conducted on 197 CT volumes, and compared to other three automatic bone segmentation methods. Out of the four tested approaches, the proposed algorithm achieved most accurate results and segmented the femur correctly in 81% of the cases.