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1
Negus, Charles Hugh. "Three dimensional dynamic hypoelastic remodeling in the proximal femur /". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2005. http://wwwlib.umi.com/cr/ucsd/fullcit?p3208622.
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Kuliwaba, Julia Suzanne. "Gene expression, bone remodelling, and microdamage in the human proximal femur: a molecular histomorphometric analysis of osteoarthritic bone". Title page, contents and summary only, 2003. http://web4.library.adelaide.edu.au/theses/09PH/09phk956.pdf.
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Ryan, Timothy Michael. "The structure and function of trabecular bone in the femoral head of strepsirhine primates". Access restricted to users with UT Austin EID Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3023558.
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Li, Bixia. "Mechanotransduction in bone passive and load-induced fluid transport in rat femora /". Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=2017.
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Thesis (M.S.)--West Virginia University, 2001.Title from document title page. Document formatted into pages; contains vii, 78 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 63-69).
5
Newman, Kyle D. "3D Modeling and Finite Element Analysis of Femur After Removing Surgical Screws". OpenSIUC, 2016. https://opensiuc.lib.siu.edu/theses/2025.
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Often bone fractures are joined by inserting metal plates and screws to hold the fragmented bone under compression. However, after the fractured bone is healed removing the screws leaves holes in the bone which takes months to fill up and heal completely. The goal of this research is to investigate those voids specifically in a finite element model of a femur. The holes were found to experience high stress that can easily lead to crack propagations during everyday activities. Finite element models of femurs were modeled after two common fracture fixation systems, specifically just after the plates, rods and screws are removed. To observe the stress levels bones are likely to experience, common mechanical tests that are relevant to or associated with common daily activities were performed. While the 3-point bending tests did not yield significant results, the compression and torsion tests produced high stress areas near the screw holes. In certain cases, the von Mises’ stress reached 3.66 x 106 N/mm2. Our finite element modeling seeks to establish groundwork for future explorations on the holes created by fracture fixation hardware. In the future, this work will lead to redesigning of fixation systems with reduced stress concentration around the holes. Therefore, the initiation of new cracks around these holes will be limited during everyday activity.
6
Brown, Christopher U. "Time-dependent circumferential deformation of cortical bone subjected to internal radial loading". Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=1861.
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Thesis (Ph. D.)--West Virginia University, 2001.Title from document title page. Document formatted into pages; contains xv. 191 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 166-183).
7
Westfall, Carola Hammer 1953. "Bone mineral content of femur, lumbar vertebrae, and radius in eumenorrheic female athletes". Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276757.
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This study compared bone mineral index (BMI, gm/cm²) of the femur, spine, and radius, measured by photon absorptiometry in various groups of eumenorrheic female athletes. The sample included body builders (11), swimmers (13), runners (5 collegiate, 11 recreational), and inactive controls (18) averaging 25 years of age, ranging from 17 to 38 years. Lumbar vertebral BMI for body builders (1.40 gm/cm²) was significantly (p ≤ 0.05) greater than controls (1.25 gm/cm²). The body builders' femoral neck BMI (1.09 gm/cm²) was significantly greater than swimmers (0.97 gm/cm², recreational runners and controls (0.95 gm/cm²). Years of exercise history and calcium consumption were not significant predictors of BMI. Correlation coefficients between fat-free body and all BMI sites were significant and more closely related to bone mineral than other variables (weight, height, weight/height²). Correlation coefficients for proximal and distal radius BMI and femoral and spine BMI were significant, the distal radius having higher association.
8
Kennedy, Eric Allen. "Lateral and Posterior Dynamic Bending of the Mid-Shaft Femur: Fracture Risk Curves for the Adult Population". Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/32216.
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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
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Gleeson, Garrett Thomas. "DEVELOPMENT OF A SUBJECT SPECIFIC FINITE ELEMENT MODEL USED TO PREDICT THE EFFECTS OF A SINGLE LEG EXTENSION EXERCISE". DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/397.
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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.
10
Findikoglu, Gulin. "An Experimental Study Of Mechanical Properties Of Non Enzymatically Glycated Bovine Femur Cortical Bone". Phd thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614536/index.pdf.
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The aim of this study is to investigate the deterioration in mechanical integrity of the collagen network in bovine bone with aging, which are related to fracture toughness. Age-related changes in collagen molecular structures formed by non-enzymatic glycation were examined and indentation fracture technique was used as a method for measuring the microstructural toughness of cortical bone. Microcrack propagation characteristics of bone for fragility were also studied.
Young and old group of bovine cortical bone specimens were grouped into 2 as ribosylated and non-ribosylated which were rested in solutions for four weeks. Series of indentations were made on bone specimen groups for each of five masses 10g, 25g, 50g, 100g and 200g for 10 sec to detect the effect of applied indentation load. The applied load was increased to 300g, 500g, 1000g and 2000g for 10 sec to be able to make microcracks. Series of indentations were made on bone specimen groups for each of five durations 5sec, 10sec, 20sec, 30sec for 100g to study the effect of indentation duration. Specimens were examined in the wet and dry state while studying the factors effecting microhardness measurement.
Microhardness values measured by 10g of load for 10sec were indifferent between the ribosylated and non-ribosylated groups in the young and old bovine bone pointing that this load is not indicative of the structural collagen changes. Loads of 25g, 50g, 100g and 200g for 10 sec were able to differ ribosylated bone from non-ribosylated bone for the young and old bovine bones. Degree of microhardness increased with increased incubation period. Microhardness of dry specimens being either ribosylated or non-ribosylated were found to be statistically higher than wet specimens in young and old bone except for 10g for 10sec.
It has been shown that the calculated fracture toughness measured by the indentation method is a function of indentation load. Additionally, effect of indentation size might have resulted in a higher toughness measurement for higher indent loads with longer cracks even if the toughness is not actually higher.Methods using indentation technique has difficulty in relating the resistance to crack growth to the Mode I fracture toughness definition.Indentation fracture toughness allows sampling only one point on the Rcurve methods and was not considered as successful for assessing materials with rising R
curve. Toughness is ranked incorrectly among riboslated and non-ribosylated bovine bone by this technique. Presence of extrinsic toughening mechanisms including crack bridging due to uncracked ligaments and collagen fibers were directly observed by scanning electron microscope. Ribosylated bone was found to have lower number of collagen bridging compared ton on-ribosylated bovine bone.As a summary, indentation fracture method by Vickers indentation in bone is a method for measuring the fracture toughness.
11
ABU, HAMDAN NATALIE. "SCLEROSTIN IMMUNOREACTIVITY INCREASES WITHIN THE CORTICAL BONE OSTEOCYTES IN THE FEMUR OF AGING MICE". Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/612463.
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Sclerostin, a secreted glycoprotein, is known to down-regulate osteocyte differentiation
from osteoblasts and acts as a negative modulator of bone formation. It is well established that
serum sclerostin levels increase with age but the relationship between changes of cellular
expression of sclerostin with age is not well known. Immunohistochemical staining and confocal
microscopic analysis of sclerostin immunoreactivity (sclerostin-IR) in the femurs of 4, 9, and 24
month old adult C3H/HeJ male mice was performed. Detectable levels of sclerostin-IR were
found in cortical bone osteocytes of the femur in all age groups using an antibody directed
against sclerostin. Phalloidin and DAPI were used to mark all osteocytes in cortical bone to
detect osteocyte/ sclerostin-IR colocalization. Sclerostin-negative and sclerostin-positive
expressing osteocytes were detected in close proximity throughout the cortical bone. Only a
subset of osteocytes expressed sclerostin and this ratio of sclerostin positive osteocytes increased
with age, from 38.5 ± 1.6% to 43 ± 3.6% to 49 ± 2.3% in young, middle-aged, and old mice,
respectively. Understanding the potential mechanisms that drive these age-related changes may
influence the therapeutic potential of age-related diseases like osteoporosis.
12
Lai, Wang-to Derek. "Prediction of pathological fracture risk due to metastatic bone defect using finite element method". Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B37060831.
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Simpson, David John. "A finite element strategy applied to intramedullary nailing of the proximal femur". Thesis, Brunel University, 2005. http://bura.brunel.ac.uk/handle/2438/7894.
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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.
14
Nakashima, Hiroatsu, Hirohisa Katagiri, Mitsuru Takahashi i Hideshi Sugiura. "Survival and Ambulatory Function after Endoprosthetic Replacement for Metastatic Bone Tumor of the Proximal Femur". Nagoya University School of Medicine, 2010. http://hdl.handle.net/2237/12905.
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Stülpner, Martin. "Various continuum bone remodelling algorithms applied to the proximal femur in two and three dimensions". Master's thesis, University of Cape Town, 1995. http://hdl.handle.net/11427/21342.
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This study investigates the behaviour of bone when it is subjected to mechanical loading. This is important in fields such as orthopaedics and implant design. Various models of bone remodelling are discussed, and a strain energy based as well as a strain remodelling based algorithm are applied in two and three dimensions. Properties such as dependence on initial conditions, development of physiologically realistic solutions and existence of long-term steady states are investigated. The strain based model has some advantages in that it is defined in terms of physiologically meaningful and measurable parameters and that it develops a long-term steady state solutions different from the case where the bone either resorbs completely or reaches cortical density.
16
Kasturiarachi, Courtney M. "An Introductory Analysis of Wolff's Law: The Genetic Influence on Bone Morphology". Kent State University Honors College / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ksuhonors1587931597177472.
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Henderson, Keyanna Brielle. "Understanding the Effects of Long-Duration Spaceflight on Fracture Risk in the Human Femur Using Finite Element Analysis". DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2255.
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Long-duration spaceflight has been shown to have significant, lasting effects on the bone strength of astronauts and to contribute to age-related complications later in life. The microgravity environment of space causes a decrease in daily mechanical loading, which signals a state of disuse to bone cells. This affects the bone remodeling process, which is responsible for maintaining bone mass, causing an increase in damage and a decrease in density. This leads to bone fragility and decreases overall strength, posing a risk for fracture. However, there is little information pertaining to the timeline of bone loss and subsequent fracture risk.
This study used finite element analysis to model the human femur, the bone most adversely affected by spaceflight, and to simulate the environments of Earth preflight, a six-month mission on the International Space Station, and one year on Earth postflight. Changes in the properties of cortical and trabecular bone in the femoral neck were measured from the simulations, and used to provide evidence for high fracture risk and to predict when it is most prominent.
It was found that a risk for fracture is extremely evident in the femoral neck in both cortical and trabecular bone. Cortical bone in the inferior neck exhibited high magnitudes of damage, while the superior neck suffered the greatest increases in damage that proceeded to increase upon return to Earth. The density of trabecular bone decreased the most significantly and was not fully recovered in the following year. While it is still unclear exactly when these changes cause the greatest risk for fracture, it is possible that they will add to and advance the onset of medical complications such as osteoporosis. Additionally, the results of this study support the claim that the current countermeasure of inflight exercise is insufficient in sustaining bone mass and preserving skeletal health. The effects of long-duration spaceflight on bone health should continue to be investigated especially if future missions are to last as long as one to three years.
18
Ben, Souda Karima. "Finite element formulation of the bone adaptation process following arthroplasty and application to the distal femur". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ29890.pdf.
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Ben, Souda Karima. "Finite element formulation of the bone adaptation process following arthroplasty and application to the distal femur". Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41982.
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This thesis presents the formulation of a general finite element program for the computation of the bone adaptation process after total joint arthroplasty. This program is applied to study this phenomenon in the distal femur resurfaced with a prosthetic component whose fixation is achieved by bone ingrowth. The motivation for this formulation and application stems from the fact that evidence of adverse bone adaptation after total joint arthroplasty is being increasingly reported in the literature.The stability of the bone adaptation model is investigated in terms of the exponents of some of its constitutive equations. These exponents are determined based on previous experimental studies and based on the constraint of the stability criterion. The iterative procedure that models the bone adaptation process is evaluated by comparing the computed results with analytical solutions for the density in a beam. The finite element model of the resurfaced bone takes into account the frictional properties of the contact between bone and the prosthetic component. The general contact formulation is evaluated by comparing the computed results with analytical solutions for the contact pressures in test situations for which these solutions are available.
The application of the general program to the resurfaced distal femur clarifies the role of the model variables in terms of their influence on the computed bone adaptation. The computed results compare favourably with the available clinical observations of bone adaptation in the distal femur following total knee arthroplasty. Furthermore, the present application allows the investigation of the possible beneficial effects of some of the prosthesis design parameters.
20
Glatt, Vaida. "Influence of the mechanical environment upon the healing of segmental bone defects in the rat femur". Thesis, University of Warwick, 2009. http://wrap.warwick.ac.uk/34649/.
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Loss of large segments of bone creates critical size defects (CSDs). These fail to heal spontaneously and present major clinical challenges to orthopaedic surgeons. The research described in this thesis is based upon the hypothesis that the healing of CSDs is responsive to the ambient mechanical environment, and can be accelerated by mechanical modulation. This hypothesis was tested in rat, femoral CSDs treated with recombinant, human, bone morphogenetic protein-2. For this study I designed novel external fixators allowing experimental control over the local mechanical environment. These were characterised by extensive mechanical testing prior to evaluation in the rat model. Low stiffness fixators induced callus formation 9 days after surgery, whereas rigid fixation delayed it until 2 weeks. All defects were radiologically bridged after 3 weeks. Rats were euthanised after 8 weeks and the defects evaluated by a battery of imaging, mechanical and histological tests. All confirmed the superiority of the lowest stiffness fixators. Based upon these data, I hypothesised that healing would be improved by imposing low stiffness for the first two weeks of healing, followed by high stiffness for the remaining six weeks. The experimental data confirm that this regimen dramatically accelerated callus formation and maturation, and induced faster remodelling of endosteal and periosteal callus. This was associated with higher failure strength, fewer trabeculae, decreased callus size and thicker and more uniform distribution of new cortical bone. Histologically it was not possible to detect cartilage within the defects prior to the appearance of bone, suggesting that healing either does not occur through endochondral ossification, or that this process is very rapid. These data confirm that the healing of CSDs is highly responsive to the ambient mechanical environment, allowing the rate and quality of healing to be manipulated. This information will help develop more efficient ways to heal CSD clinically.
21
Javid, Samad. "Optimized Evaluation of Bone Tissue Material Properties by Inverse Finite Element Analysis and Femur Fracture Testing". Diss., North Dakota State University, 2015. https://hdl.handle.net/10365/27598.
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The main objective of this research is to characterize bone inhomogeneous elastic, yield, and post-yield behaviors, using a computational-experimental approach. The current study uses the force-displacement results of one hundred four cadaveric femora that were previously tested to fracture in a fall on the hip loading configuration. Recorded force-displacement data are used to determine stiffness, yield force, and femoral strength values. Finite element (FE) models of the femora are developed from the quantitative computed tomography scans captured before the fracture tests. A power law, or a sigmoid function, is used to determine the elastic modulus from the ash densities for each case modeled. The models are used for FE simulations that mimic the experiments. Inverse finite element analysis is employed to identify the unknown coefficients in the bone density-elasticity relationships. Optimization algorithms are used to minimize the error function between the experimental and FE estimated results in a large subset of female femora. The results of the obtained relationships show a good agreement with the experimental data. This contributes to a coefficient of determination of 70%, which is higher than those of previously proposed density-elasticity relationships on the same set of femora. The parts of the bones with the densities up to 0.5 g/cm3, play an important role in the deformation of the neck and the head of the femur. While power law and sigmoid function show similar correlation in the prediction of stiffness, distribution of stresses and strains are notably different, showing different response in the yield and post-yield behavior.
To simulate the material damage, a power density-yield strain relationship is used as the failure criterion in FE models, assuming a ductile and a brittle material behavior for the bone. The unknown coefficients in the density-yield strain relationship are identified for the ductile and brittle material models. The ductile material model shows a more realistic post-yield behavior
iv
than the brittle model, but it is computationally expensive and may face convergence issues due to nonlinearities. The brittle material model, on the other hand, estimates the bone strength fairly and, due to its simplicity, it seems more applicable for clinical use.Army Research Office, National Institutes of Health (NIH) (grant AR027065Z-30S1), the Grainger Foundation (Grainger Innovation Fund), Opus CT Imaging Resource of Mayo Clinic (NIH construction grant RR018898)
National Institute of Health (NIH grant AR027065Z-3051, NIH construction grant RR018898)
Grainger Foundation (Grainger Innovation Fund)
22
Lai, Wang-to Derek, i 黎弘道. "Prediction of pathological fracture risk due to metastatic bone defectusing finite element method". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B37060831.
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Monro, Philip Peter. "The growth of the chick femur in ova and its growth and repair in vitro and on the chorioallantoic membrane". Thesis, University of Southampton, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.276515.
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Copploe, Joseph V. II. "In Vivo Strains in the Femur of the Nine-Banded Armadillo (Dasypus novemcinctus)". Youngstown State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1403533523.
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Taylor, Mark. "Finite element analysis of cancellous bone stresses within an implanted proximal femur and their relationship to implant migration". Thesis, Queen Mary, University of London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438300.
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Staals, Eric Lodewijk <1976>. "The use of expandable megaprostheses for reconstruction of the distal femur in pediatric patients after bone tumor resection". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amsdottorato.unibo.it/9193/1/Tesi%20Finale%20Staals%202020pp.pdf.
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Expandable prostheses are becoming increasingly popular in the reconstruction of children with bone sarcomas of the lower limb. Since the introduction of effective chemotherapy in the treatment of these pathologies, in the 70s, there has been need for new limb salvage techniques. In children, limb salvage of the lower limbs is particularly challenging, not in the last place, because of the loss of growth potential. Therefore, expandable prostheses have been developed. However, the first experiences with these implants were not very successful. High complication rates and unpredictable outcomes raised major concerns on this innovative type of reconstruction. The rarity of the indication is one of the main reasons why there has been a relatively slow learning curve and implant development regarding this type of prosthesis. This PhD thesis, gives an overview of the introduction, the development, the current standards, and the future perspectives of expandable prostheses for the reconstruction of the distal femur in children.
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Thompson, M. L., S. R. Chartier, S. A. Mitchell i P. W. Mantyh. "Preventing painful age-related bone fractures: Anti-sclerostin therapy builds cortical bone and increases the proliferation of osteogenic cells in the periosteum of the geriatric mouse femur". SAGE PUBLICATIONS INC, 2016. http://hdl.handle.net/10150/622356.
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Age-related bone fractures are usually painful and have highly negative effects on a geriatric patient's functional status, quality of life, and survival. Currently, there are few analgesic therapies that fully control bone fracture pain in the elderly without significant unwanted side effects. However, another way of controlling age-related fracture pain would be to preemptively administer an osteo-anabolic agent to geriatric patients with high risk of fracture, so as to build new cortical bone and prevent the fracture from occurring. A major question, however, is whether an osteo-anabolic agent can stimulate the proliferation of osteogenic cells and build significant amounts of new cortical bone in light of the decreased number and responsiveness of osteogenic cells in aging bone. To explore this question, geriatric and young mice, 20 and 4 months old, respectively, received either vehicle or a monoclonal antibody that sequesters sclerostin (anti-sclerostin) for 28 days. From days 21 to 28, animals also received sustained administration of the thymidine analog, bromodeoxyuridine (BrdU), which labels the DNA of dividing cells. Animals were then euthanized at day 28 and the femurs were examined for cortical bone formation, bone mineral density, and newly borne BrdU+ cells in the periosteum which is a tissue that is pivotally involved in the formation of new cortical bone. In both the geriatric and young mice, anti-sclerostin induced a significant increase in the thickness of the cortical bone, bone mineral density, and the proliferation of newly borne BrdU+ cells in the periosteum. These results suggest that even in geriatric animals, anti-sclerostin therapy can build new cortical bone and increase the proliferation of osteogenic cells and thus reduce the likelihood of painful age-related bone fractures.
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Rice, Michael Blair. "Effects of type-I collagen fractional composition and pyridinium crosslink content on cortical bone strength in the human femur". Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=1840.
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Thesis (M.S.)--West Virginia University, 2001.Title from document title page. Document formatted into pages; contains viii, 88 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 81-88).
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Rabelo, Luis Raimundo Serra. "Estudo comparativo de materiais de preenchimento osseo sobre o processo de regeneração ossea guiada em defeitos perimplantares : analise histologica e histometrica em femur de coelhos". [s.n.], 2001. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289437.
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Orientador: Jose Ricardo de Albergaria-BarbosaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: O objetivo deste trabalho foi realizar um estudo comparativo de diferentes materiais preenchimentos ósseos sobre o processo de regeneração óssea guiada em defeitos perimplantares do tipo fenestração, realizados em fêmur de coelhos. Defeitos circulares de 2,6mm de diâmetro foram confeccionados na face medial do fêmur, de forma a expor a superfície do implante. Foram colocados 40 implantes de titânio de 6mm de comprimento por 2,6mm de diâmetro, bilateralmente, em fêmur de coelhos. Os defeitos foram preenchidos, de acordo com o grupo estudado, com: vidro bioativo, matriz óssea liofilizada de origem humana, osso autógeno e preenchimento por coágulo, que serviu como controle do experimento. Todos os defeitos, após preenchimento, foram protegidos por membrana de celulose. Os animais foram sacrificados após períodos de 3 e 6 semanas, quando blocos ósseos contendo os implantes, foram descalcificados e processados para posterior análise histológica em microscopia óptica comum e análise histométrica. Os dados histométricos revelaram melhores resultados de formação óssea no período de 3 semanas para os grupos Osso autógeno e Osso liofilizado (37,8% e 37,1%, respectivamente), e não apresentaram diferenças estatísticas significantes entre si. No período de 6 semanas o grupo Osso autógeno apresentou os maiores resultados de formação óssea (64,1%)
Abstract: The purpose of this study was compare the bone healing after different bone grafting materiais in bone tissue regeneration around implants in rabbit' s femur. Forty 6 x 2.6mm titanium implants were placed, bilaterally, in the femur of twenty New Zealand rabbits. Circular defects (2.6mm in diameter) were created at mesial of each femur, in order to expose implant threads. Defects were filled with human demineralized freeze-dried bone (Dembone), rabbit bone-chips autografts (autogenous bone) , bioactive glass granules (Perioglas) and control group filled with blood clot (control). Ali defects were protected with cellulose membranes. Rabitts were sacrificed 3 and 6 weeks after graft placement, the specimens were cut into block sections on a low speed bur and submited to histologic and histometric analysis. Among the graft materiais, autogenous bone and human demineralized freeze-dried bone provided the greatest amount of bone formation (37,8% and 37,1%, respectively) after 3 weeks of healing, with no statistically signifcant difference between them. After 6 weeks, autogenous bone provided the densest and greatest amount bone formation (64,1 %). Between 3 and 6 weeks, the greatest amount of bone formation was provided by autogenous bone grafts, and the control group showed a lesser quantity of bone formation as compared to the grafted groups
Doutorado
Cirurgia
Doutor em Clínica Odontológica
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Hryce, Trevor J. "Modeling the Long Term Effects of Alendronate on Bone Mass Preservation of the Femur with Articular Surface and Total Hip Replacements". DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/277.
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Calculating femoral bone density changes after hip arthroplasty is of interest to researchers and clinicians for predicting the longevity of the prosthetic implant and the surrounding bone. Recently clinicians have been administering bisphosphonate drugs in an attempt to reduce the bone resorption due to stress shielding caused by these implants. Current strain-adaptive computational models with bisphosphonate treatment don’t predict the long term effects or look at treatment with hip resurfacing implants. The main goal of this study was to create and validate a computer model of the human femur incorporating a bone remodeling algorithm based on biological remodeling processes and bisphosphonate drug treatment. A secondary objective was to then create various bisphosphonate drug treatment scenarios and evaluate differences in bone density, damage, and activation frequency. Experimental studies were used to validate the model and the effects of bisphosphonates. A finite element model created from a CT scan of a cadaveric femur, a bone remodeling algorithm, and a bisphosphonate algorithm were incorporated into the model with loading conditions representative of walking and stair climbing. The model was allowed to evolve from an initial state of homogenous density to a steady state form with a density similar to that of the femur. Reduced loading representative of decreased muscle forces were applied to the steady state form to simulate preoperative conditions of a patient with hip osteoarthritis. Both a femoral hip resurfacing component and an uncemented, tapered stem were then integrated in the computer model representative of a postoperative state. Bisphosphonate treatment was applied to both the preoperative and postoperative states in several scenarios after untreated simulations. Bone loss was predicted over a six year postoperative period for both implants and varying treatments. Femoral bone loss in bisphosphonate treatment scenarios matched results seen clinically. Bone volume fraction (BVF) showed little change between one year preoperative to one year postoperative Alendronate treatment and one year postoperative Alendronate treatment for a specific implant type. Both treatment scenarios increase the BVF over no treatment. Pretreating with Alendronate appears to help against femoral neck fracture. This study successfully created a three-dimensional finite element model able to simulate long term effects of the remodeling process in bone with Alendronate treatment. The results show an importance of treatment timing for both types of implants especially when potentially requiring a revision surgery.
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Yadav, Priti. "Multiscale Modelling of Proximal Femur Growth : Importance of Geometry and Influence of Load". Doctoral thesis, KTH, Strukturmekanik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-209149.
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Longitudinal growth of long bone occurs at growth plates by a process called endochondral ossification. Endochondral ossification is affected by both biological and mechanical factors. This thesis focuses on the mechanical modulation of femoral bone growth occurring at the proximal growth plate, using mechanobiological theories reported in the literature. Finite element analysis was used to simulate bone growth. The first study analyzed the effect of subject-specific growth plate geometry over simplified growth plate geometry in numerical prediction of bone growth tendency. Subject-specific femur finite element model was constructed from magnetic resonance images of one able- bodied child. Gait kinematics and kinetics were acquired from motion analysis and analyzed further in musculoskeletal modelling to determine muscle and joint contact forces. These were used to determine loading on the femur in finite element analysis. The growth rate was computed based on a mechanobiological theory proposed by Carter and Wong, and a growth model in the principal stress direction was introduced. Our findings support the use of subject- specific geometry and of the principal stress growth direction in prediction of bone growth. The second study aimed to illustrate how different muscle groups’ activation during gait affects proximal femoral growth tendency in able-bodied children. Subject-specific femur models were used. Gait kinematics and kinetics were acquired for 3 able-bodied children, and muscle and joint contact forces were determined, similar to the first study. The contribution of different muscle groups to hip contact force was also determined. Finite element analysis was performed to compute the specific growth rate and growth direction due to individual muscle groups. The simulated growth model indicated that gait loading tends to reduce neck shaft angle and femoral anteversion during growth. The muscle groups that contributes most and least to growth rate were hip abductors and hip adductors, respectively. All muscle groups’ activation tended to reduce the neck shaft and femoral anteversion angles, except hip extensors and adductors which showed a tendency to increase the femoral anteversion. The third study’s aim was to understand the influence of different physical activities on proximal femoral growth tendency. Hip contact force orientation was varied to represent reported forces from a number of physical activities. The findings of this study showed that all studied physical activities tend to reduce the neck shaft angle and anteversion, which corresponds to the femur’s natural course during normal growth. The aim of the fourth study was to study the hypothesis that loading in the absence of physical activity, i.e. static loading, can have an adverse effect on bone growth. A subject-specific model was used and growth plate was modeled as a poroelastic material in finite element analysis. Prendergast’s indicators for bone growth was used to analyse the bone growth behavior. The results showed that tendency of bone growth rate decreases over a long duration of static loading. The study also showed that static sitting is less detrimental than static standing for predicted cartilage-to-bone differentiation likelihood, due to the lower magnitude of hip contact force. The prediction of growth using finite element analysis on experimental gait data and person- specific femur geometry, based on mechanobiological theories of bone growth, offers a biomechanical foundation for better understanding and prediction of bone growth-related deformity problems in growing children. It can ultimately help in treatment planning or physical activity guidelines in children at risk at developing a femur or hip deformity.QC 20170616
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Grant, Caroline Ann. "Design of a hip screw for injection of bone cement". Thesis, Queensland University of Technology, 2006. https://eprints.qut.edu.au/16266/1/Caroline_Grant_Thesis.pdf.
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Fracture to the neck of femur is frequently stabilised with a hip screw system, however the host bone is often weak or osteoporotic. This causes premature failure of the system, commonly by cut-out of the lag screw through the head of the femur. While augmentation of the fixation with bone cement improves the holding power and decreases failure rate, current methods of administering the cement are messy and inaccurate. This project proposes a lag screw design which allows for direct injection of the cement, via the lag screw itself, after the screw has been inserted and correctly positioned in the femur. A method is also suggested to reduce the risk of cement leakage into the joint space when the guide wire has punctured the head of the femur.
The design uses a system of holes in the threaded section of a cannulated screw to allow delivery of cement to the desired area; the modified screw was also tested with and without the tip of the screw closed. These design and implantation techniques were compared to the standard design lag screw both with and without bone cement augmentation by traditional methods.
Initial testing in a synthetic bone analogue looked promising. The modified screw with closed end performed better in push out tests than the standard screw alone and comparably with the standard screw with cement augmentation. A second phase of testing with the synthetic material was then conducted to more closely represent physiological loading conditions. In this case again the closed ended modified screw with cement augmentation outperformed the original screw and was comparable with the augmented original screw.
However, during this phase of testing problems were observed with the synthetic testing material and it was decided to conduct further testing in paired porcine cadaveric femurs. Several further problems occurred in this phase of testing, including the bending of the test screws.
It was concluded that the modified screw showed potential in being a more accurate and consistent method of cement augmentation, however neither the synthetic bone analogue or the porcine material was an adequate model of an osteoporotic human femur. If a suitable testing material could be found, continued study of this prototype may prove beneficial.
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Grant, Caroline Ann. "Design of a hip screw for injection of bone cement". Queensland University of Technology, 2006. http://eprints.qut.edu.au/16266/.
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Fracture to the neck of femur is frequently stabilised with a hip screw system, however the host bone is often weak or osteoporotic. This causes premature failure of the system, commonly by cut-out of the lag screw through the head of the femur. While augmentation of the fixation with bone cement improves the holding power and decreases failure rate, current methods of administering the cement are messy and inaccurate. This project proposes a lag screw design which allows for direct injection of the cement, via the lag screw itself, after the screw has been inserted and correctly positioned in the femur. A method is also suggested to reduce the risk of cement leakage into the joint space when the guide wire has punctured the head of the femur. The design uses a system of holes in the threaded section of a cannulated screw to allow delivery of cement to the desired area; the modified screw was also tested with and without the tip of the screw closed. These design and implantation techniques were compared to the standard design lag screw both with and without bone cement augmentation by traditional methods. Initial testing in a synthetic bone analogue looked promising. The modified screw with closed end performed better in push out tests than the standard screw alone and comparably with the standard screw with cement augmentation. A second phase of testing with the synthetic material was then conducted to more closely represent physiological loading conditions. In this case again the closed ended modified screw with cement augmentation outperformed the original screw and was comparable with the augmented original screw. However, during this phase of testing problems were observed with the synthetic testing material and it was decided to conduct further testing in paired porcine cadaveric femurs. Several further problems occurred in this phase of testing, including the bending of the test screws. It was concluded that the modified screw showed potential in being a more accurate and consistent method of cement augmentation, however neither the synthetic bone analogue or the porcine material was an adequate model of an osteoporotic human femur. If a suitable testing material could be found, continued study of this prototype may prove beneficial.
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Schleifenbaum, Stefan, Michael Schmidt, Robert Möbius, Thomas Wolfskämpf, Christian Schröder, Ronny Grunert, Niels Hammer i Torsten Prietzel. "Load and failure behavior of human muscle samples in the context of proximal femur replacement". Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-204698.
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Background: To ensure adequate function after orthopedic tumor reconstruction, it is important to reattach the remaining soft tissue to the implant. This study aimed at obtaining mechanical properties of textile muscle-implant and muscle-bone connections in a preliminary test. Methods: Two groups of soft-tissue attachment were mechanically tested and compared: Native bone-muscle samples obtained from human femora and muscles attached to a prosthetic implant by means of Trevira® attachment tubes. Additionally, muscle samples were tested with muscle fibers aligned parallel and perpendicular to the tension load. A uniaxial load was exerted upon all samples. Results: Failure loads of 26.7 ± 8.8 N were observed for the native bone-muscle group and of 18.1 ± 9.9 N for the Trevira® group. Elongations of 94.8 ± 36.2 % were observed for the native bone-muscle group and 79.3 ± 51.8 % for the Trevira® group. The location of failure was mainly observed in the central area of the muscle fibers. Muscle fibers with parallel fiber orientation (47.6 ± 11.5 N) yielded higher tensile strength than those with perpendicular fiber orientation (14.8 ± 4.1 N). Conclusions: Our experiments showed that higher forces were transmitted in the origin and insertion areas than in areas of flat soft tissue reconstruction using attachment tubes. The data indicate that the tested material allows reattaching muscles, but without reinforcing the insertion site. Therefore, attachment tubes with region-dependent
and potentially anisotropic material behavior might be advantageous to optimize muscle-bone load transmission after surgery, which may allow lower complication rates and shorter physical recovery.
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Mao, Liangyan. "Assessment of Bone Regeneration in a Rat Femur Defect Model Following Recombinant Human Bone Morphogenetic Protein 2 Delivery from Keratin Hydrogels with Tunable Rates of Degradation: Micro-CT Analysis and Histology". Miami University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=miami148068386349526.
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Chartier, Stephane R., Stefanie AT Mitchell, Lisa A. Majuta i Patrick W. Mantyh. "Immunohistochemical localization of nerve growth factor, tropomyosin receptor kinase A, and p75 in the bone and articular cartilage of the mouse femur". SAGE PUBLICATIONS INC, 2017. http://hdl.handle.net/10150/626456.
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Sequestration of nerve growth factor (NGF) significantly attenuates skeletal pain in both animals and humans. However, relatively little is known about the specific cell types that express NGF or its cognate receptors tropomyosin receptor kinase A (TrkA) and p75 in the intact bone and articular cartilage. In the present study, antibodies raised against NGF, TrkA, and p75 (also known as CD271) were used to explore the expression of these antigens in the non-decalcified young mouse femur. In general, all three antigens displayed a remarkably restricted expression in bone and cartilage with less than 2% of all DAPI+ cells in the femur displaying expression of any one of the three antigens. Robust NGF immunoreactivity was found in mostly CD-31- blood vessel-associated cells, a small subset of CD-31+ endothelial cells, an unidentified group of cells located at the subchondral bone/articular cartilage interface, and a few isolated, single cells in the bone marrow. In contrast, p75 and TrkA were almost exclusively expressed by nerve fibers located nearby NGF+ blood vessels. The only non-neuronal expression of either p75 or TrkA in the femur was the expression of p75 by a subset of cells located in the deep and middle zone of the articular cartilage. Understanding the factors that tightly regulate the basal level of expression in normal bone and how the expression of NGF, TrkA, and p75 change in injury, disease, and aging may provide insights into novel therapies that can reduce skeletal pain and improve skeletal health.
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Hanebeck, Jan. "Postoperative Knochendichteänderungen am Femur nach Implantation der zementfreien Zweymüller-Hüftendoprothese unter Berücksichtigung klinischer und röntgenologischer Parameter". Doctoral thesis, Humboldt-Universität zu Berlin, Medizinische Fakultät - Universitätsklinikum Charité, 2001. http://dx.doi.org/10.18452/14612.
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Bei der Rekonstruktion des durch Krankheit oder Trauma geschädigten Hüftgelenkes hat sich der Ersatz des Gelenkes durch eine totale Endoprothese heute allgemein durchgesetzt. Dabei hat unter Beachtung einer differenzierten Indikationsstellung sowohl die zementierte als auch die zementfreie Technik ihre Anwendungsberechtigung. Das Problem der dauerhaften Verankerung der zementfreien Hüftendoprothese ist jedoch trotz ständiger Weiterentwicklung von Operationstechnik, Implantatdesign und Werkstoffen bis heute nicht abschließend gelöst. Die häufigste Versagensursache ist dabei die aseptische Schaftlockerung, die mit Veränderungen des knöchernen Lagers einhergeht. Mit der Osteodensitometrie existiert eine Technik, die eine schnelle, nichtinvasive und quantitative Beurteilung der Knochenmasse erlaubt. In der vorliegenden Querschnittsstudie wurden 95 Zweymüller-Schaftimplantate zwei, vier bzw. sechs Jahre nach Implantation untersucht. Dabei wurden die Ergebnisse der klinischen Untersuchung und der konventionellen a.p. Röntgenaufnahme den mit Hilfe der DEXA-Technik ermittelten Knochendichteänderungen am Femur gegenübergestellt. Der Vergleich von Knochendichteänderungen in einzelnen Femurabschnitten in Abhängigkeit von der Implantationsdauer läßt Rückschlüsse auf das Schaftdesign zu.When hip function is several impaired by disease or trauma, total hip replacement is preferred treatment of choice today. The consideration of a differentiated position of indication justifies both - the application of the cemented as well as the cement free technique. But despite of constant further development of operation techniques, design of implantation and the used materials is the problem of a permanent embodiment of the non-cemented hip prosthesis till today not finally solved. The aseptic relaxation of the stem is the most frequent reason for failure. This is accompanied by changes of the osseous bed. With the osteodensitometry exists a technique that makes a fast, non-invasive and quantitative assessment of the bone mass possible. In this present cross-section study 95 Zweymüller-stem-implants were examined two, four and six years after the implantation. The results of the clinical examination and the results of the conventional X-ray picture were compared with the changes of the thigh femur bone density that were ascertained by the DEXA-technique. The comparison of changes of the bone density in single femur sections in dependence on the duration of the implantation allows one to draw conclusions from the design of the stem.
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Iori, Gianluca [Verfasser], Kay [Akademischer Betreuer] Raum, Kay [Gutachter] Raum, Claudia [Gutachter] Fleck i Richard [Gutachter] Weinkamer. "Development of cortical bone biomarkers for the prediction of femur strength / Gianluca Iori ; Gutachter: Kay Raum, Claudia Fleck, Richard Weinkamer ; Betreuer: Kay Raum". Berlin : Technische Universität Berlin, 2019. http://d-nb.info/1201410959/34.
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Cussler, Eleanor Christine. "Weight moved in one year of strength training and femur trochanter bone density change in 140 post-menopausal women: A dose-response relationship". Thesis, The University of Arizona, 2000. http://hdl.handle.net/10150/278755.
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Osteoporosis or very low bone mineral density (BMD) has been shown to increase the risk of hip fracture in postmenopausal women. Exercise, particularly strength training, may increase BMD in older women and thus help prevent osteoporosis and hip fracture. Change in femur trochanter BMD was examined in 140 postmenopausal women enrolled in the Bone Estrogen Strength Training (BEST) Study who performed a one-year progressive resistance training program. A significant 0.012 ± 0.024 g/cm² increase in femur trochanter BMD was found from baseline to 1 year for the entire group. In multiple linear regression, the increase was positively and linearly related to the total weight moved (p < .015) even after adjustment for age, baseline trochanter BMD, HRT status, change in body weight, cohort, and fitness center. Among individual exercises, the squats showed the strongest while the back extension exhibited the weakest association with change in BMD.
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Malosso, Tatiana Gaion. "Análise de um modelo do processo de instalação de osteopenia em ossos corticais de ratas ovariectomizadas". Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/82/82131/tde-27012005-143338/.
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A osteoporose é um enfraquecimento progressivo dos ossos, que ficam cada vez mais sujeitos a fraturas. Embora possa acometer ambos os sexos, ela é mais freqüente nas mulheres após a menopausa devido à diminuição dos hormônios femininos, os estrógenos. É uma doença que avança lentamente, sem sintomas, geralmente sem ser percebida até que aconteça uma fratura. Uma vez instalada a osteoporose, tem que se evitar maior perda óssea para prevenir fraturas. O objetivo deste trabalho é analisar o quadro de instalação de osteopenia em ossos corticais de ratas ovariectomizadas. Foi utilizado um modelo de osteopenia em 29 ratas Wistar ovarectomizadas com massa corpórea de 250 gramas. Os animais foram divididos em 6 grupos experimentais e eutanaziados em períodos diferentes: o primeiro grupo foi eutanaziado 30 dias após a cirurgia, que corresponde ao tempo de início da osteopenia, e a partir daí, os demais grupos foram eutanaziados numa seqüência de 15 dias até o 105º dia. A avaliação do quadro de instalação foi realizada através de medidas antropométricas e de propriedades mecânicas dos fêmures (ensaio de flexão de três pontos). Cada um dos itens obtidos foram comparados utilizando-se o programa GraphPad InStat 3. O teste t-Student foi aplicado para checar a variação do peso corporal com p < 0,05. Aplicaram-se os testes ANOVA e Student-Newmam-Keuls com coeficiente de variação também menor que 5% para os demais itens analisados. Observou-se um aumento significativo no comprimento dos fêmures durante o primeiro mês de experimento, assim como na carga máxima aplicada. Os resultados obtidos neste estudo sugerem que a ovariectomia é um fator que não causa grandes alterações mecânicas e geométricas na região cortical dos fêmures de ratas no período analisadoOsteoporosis is a progressive weakness of bones, which are more and more subjects to fractures. Although it happens to men and women, it is more frequent in postmenopausal women due to a decrease of female hormones. It is a disease without symptoms and it is usually noticed only after a fracture. Once the osteoporosis is installed, a bigger bone loss must be avoided in order to prevent a fracture. This study aims to analyze the osteopenia installation process in cortical bones of ovariectomized rats. An osteopenia model was used in 29 ovariectomized Wistar female rats with body weight of 250 g. Animals were divided in 6 experimental groups, the first group was sacrificed 30 days after the surgery and, the other groups, every 15 days on until the 105th day. The evaluation of installation process was made through anthropometrics and mechanical proprieties of femur (three-point bending test). Program GraphPad InStat 3 was used in order to compare the observed items. T-student test was used to check the body weight variation with p < 0,05 and tests ANOVA and Student-Newmam-Keuls were applied to the other items (p < 0,05). A significant increase in femur length and in maximum bending load were obtained. The found results in this research suggest that ovariectomy is a factor that does not cause significant mechanical and geometric alterations on cortical region of femurs in female rats during the analyzed period
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Townsend, Katy Louise. "The Use of Radiographs, Dual-energy X-ray Absorptiometry, Quantitative Computed Tomography and Micro-computed Tomography to Determine Local Cancellous Bone Quality in the Canine Proximal Femur". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1336769521.
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Mendonça, Sandra Maria Holanda de. "Avaliação funcional dos pacientes portadores de sarcomas osseos submetidos ao tratamento cirurgico utilizando a endoprotese total ou parcial, na substituição da extremidade distal do femur". [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/312080.
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Orientadores: Silvia Regina Brandalise, Alejandro Enzo CassoneDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
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Resumo: Introdução: O Osteossarcoma e o Sarcoma de Ewing são as principais neoplasias malignas primárias ósseas, que acometem indivíduos menores de 15 anos de idade. A cirurgia com preservação do membro faz parte do tratamento atual. O objetivo do estudo foi comparar retrospectivamente, os resultados funcionais dos pacientes submetidos à ressecção do fêmur distal e reconstrução com endoprótese não convencional parcial ou total do joelho. Material e Método: Foram analisados 26 pacientes portadores de sarcomas ósseos da extremidade distal do fêmur, admitidos no Centro Infantil Boldrini, no período de janeiro de 1990 a dezembro de 2003. Vinte e quatro pacientes eram portadores de Osteossarcoma e 2 de Sarcoma de Ewing. Quinze pacientes foram reconstruídos com endoprótese total de joelho e 11 com endoprótese parcial de joelho. Foram considerados as variáveis idade, gênero, tipo de reconstrução do membro, dor, aceitação emocional, estabilidade, movimento, deformidade, força e atividade funcional. O sistema de avaliação foi o proposto por Enneking (1987) e preconizado pela Musculoskeletal Tumor Society. Para a comparação das médias entre cada critério e, também, entre os escores finais, utilizou-se o teste de Wilcoxon, com erro alfa de 5%. Resultados: A idade variou de 5 a 21 anos, mediana=11,9 anos. A predominância foi no sexo feminino (61,5%). Na avaliação funcional, a comparação entre as médias de cada critério, foi encontrada diferença estatisticamente significativa somente relacionada ao critério estabilidade (p=0,0037). Nos demais critérios avaliados, não foi observado diferença estatisticamente significativa: movimento (p=0,7546), dor (p=0,4848), deformidade (p=0,8695), força (p=1,0000), atividade funcional (p=0,9127) e aceitação emocional (p=0,5866). Conclusão: O escore final da avaliação funcional global não apresentou diferença estatisticamente significativa (p=0,6027). O tipo de reconstrução com endoprótese distal do fêmur não interferiu nos resultados funcionais dos pacientes
Abstract: Introduction: Osteosarcoma and Ewing¿s Sarcoma are the two most common malignant primary bone neoplasms in individuals under the age of 15 years. Limb sparing surgery is a recent method of treatment. The purpose of the study is to compare functional results of patients who underwent distal femur resection and reconstruction with a hemi or total knee endoprosthesis. Methods: Were reviewed 26 patients with bone sarcomas of the distal femur admitted at Boldrini¿s Children Center between January 1990 and December 2003. Twenty-four patients presented an Osteosarcoma and the other two ones an Ewing¿s sarcoma. Fifteen patients were submitted to a total endoprosthesis and eleven to a partial one. Variables as age, sex, type of reconstruction, pain, emotional acceptance, stability, movement, deformity, strength and functional activities were studied. The evaluation system has been proposed by Enneking (1987) and preconized by The Musculoskeletal Tumor Society. For the statistical analysis among criteria and final scores the Wilcoxon test was used, with an alpha error of 5%. Results: The age ranged from 5 to 21 years, mean 11.9 years; 61.5% were female. The only statistically significant difference found in this study was related to stability (p=0.0037). No statistical significance was found on any other criteria like movement (p=0.7546), pain (p=0.4848), deformity (p=0.8695), strength (p=1.0000), functional activities (p=0.9127) and emotional acceptance (p=0.5866). Conclusion: The final score between both types of endoprosthesis did not present a statistically significant difference (p=0.6027). The type of implant for limb reconstruction did not affect the patient¿s functional results
Mestrado
Saude da Criança e do Adolescente
Mestre em Saude da Criança e do Adolescente
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Whitmarsh, Tristan. "3D reconstruction of the proximal femur and lumbar vertebrae from dual-energy x-ray absorptiometry for osteoporotic risk assessment". Doctoral thesis, Universitat Pompeu Fabra, 2012. http://hdl.handle.net/10803/94492.
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In this thesis a method was developed to reconstruct both the 3D shape and the BMD distribution of bone structures from Dual-energy X-ray Absorptiometry (DXA) images. The method incorporates a statistical model built from a large dataset of Quantitative Computed Tomography (QCT) scans together with a 3D-2D intensity based registration process.
The method was evaluated for its ability to reconstruct the proximal femur from a single DXA image. The resulting parameters of the reconstructions were subsequently evaluated for their hip fracture discrimination ability. The reconstruction method was finally extended to the reconstruction of the lumbar vertebrae from anteroposterior and lateral DXA, thereby incorporating a multi-object and multi-view approach.
These techniques can potentially improve the fracture risk estimation accuracy over current clinical practice.En esta tesis se desarrolló un método para reconstruir tanto la forma 3D de estructuras óseas como la distribución de la DMO a partir de una sola imagen de DXA. El método incorpora un modelo estadístico construido a partir de una gran base de datos de QCT junto con una técnica de registro 3D-2D basada en intensidades. Se ha evaluado la capacidad del método para reconstruir la parte proximal del fémur a partir de una imagen DXA. Los parámetros resultantes de las reconstrucciones fueron evaluados posteriormente por su capacidad en discriminar una fractura de cadera. Por fin, se extendió el método a la reconstrucción de las vértebras lumbares a partir de DXA anteroposterior y lateral incorporando así un enfoque multi-objeto y multi-vista. Estos técnicas pueden potencialmente mejorar la precisión en la estimación del riesgo de fractura respecto a la estimación que ofrece la práctica clínica actual.
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Wölfer, Jan. "The morphology of the scapula and femur of sciuromorph rodents in light of scaling, lifestyle, homoplasy, and macroevolutionary modelling". Doctoral thesis, Humboldt-Universität zu Berlin, 2020. http://dx.doi.org/10.18452/21639.
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Der Bewegungsapparat der Sciuromorpha, einer monophyletische Gruppe von ca. 300 Arten, wurde verwendet um den Effekt der Lebensweise und der Körpermasse auf die Scapula- und Femurmorphologie zu untersuchen. Diese Nagetierklade weist eine breite Vielfalt an Lebensweisen (arboreal, fossoriell, aerial) als auch Körpermassen (drei Größenordnungen umfassend) auf. Die fossorielle Lebensweise hat sich höchstwahrscheinlich dreimal unabhängig von einem arborealen Vorfahren entwickelt.
Mehr als die Hälfte der rezenten Arten wurden untersucht. Die Scapulae wurden fotografiert, während Computertomographie (CT) und Oberflächenlaserscans für die Femora verwendet wurden. Es wurden funktionsrelevante Merkmale analysiert, wie die effektive Länge der Skelettelemente, die Muskeleigenschaften soweit aus der Geometrie der Knochen ableitbar, sowie die Robustheit. Die CT-Scans wurden verwendet, um die Querschnitts- und Trabekeleigenschaften des Femurs zu analysieren. Die Gestalt wurde mittels geometrischer Morphometrie untersucht. Phylogenetic comparative methods wurden unter anderem verwendet, um den Einfluss der Phylogenie zu beurteilen als auch, ob sich die unabhängige Aneignung einer fossoriellen Lebensweise in der Evolution homoplastischer Morphologien widerspiegelt.
Die Phylogenie spielte bei der Merkmalsevolution eine vernachlässigbare Rolle. Das Auftreten signifikanter Merkmalsunterschiede zwischen den Lebensweisen sowie allometrischer Anpassungen aufgrund Veränderungen in der Körpermasse hingen von dem jeweiligen Merkmal ab. Bei einigen Merkmalen unterschied sich der Einfluss der Körpermasse signifikant zwischen den einzelnen Lebensweisen, was aber nicht die Regel zu sein scheint. Die Evolution homoplastischer Morphologien war sehr unwahrscheinlich bei den fossoriellen Gruppen. Diese Ergebnisse deuten auf eine komplexe, aber adaptive Evolutionsgeschichte dieser Skelettelemente bei den Sciuromorpha hin.The vertebrate locomotor apparatus of Sciuromorpha, a monophyletic group of ca. 300 species, was used to investigate the effect of lifestyle and body mass on the scapular and femoral morphology. This rodent clade displays a broad diversity of lifestyles (arboreal, fossorial, aerial) and body masses spanning three orders of magnitude. The fossorial lifestyle evolved most probably three times independently from an arboreal ancestor. More than half of the extant species were included. Scapulae were photographed and computed tomography (CT) and surface laser scans were acquired for the femora. Functionally relevant traits were analysed, e.g., the effective length of the skeletal element, the properties of attaching muscles as inferred from the geometry of the bones, and robustness properties. The CT scans were used to analyse the cross-sectional and trabecular properties of the femur. Bone shape was investigated using geometric morphometrics. Phylogenetic comparative methods were utilized, e.g., to assess phylogenetic inertia and whether the independent acquisition of a fossorial lifestyle is reflected in the evolution of homoplastic morphologies. Phylogenetic inertia played a neglectable role in the trait evolution. Significant differences among lifestyles as well as allometric scaling adjustments depended on the trait under consideration. For some traits, scaling differed significantly among lifestyles, although this did not appear to be the rule. Morphological homoplasy was unlikely among the fossorial groups. The results suggest a complex, but adaptive evolutionary history of these skeletal elements in Sciuromorpha.
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Salbego, Fabiano Zanini. "Enxerto ou implante homólogo na correção de defeito ósseo segmentar femoral em cães associado a inoculação da fração de células mononucleares da medula óssea". Universidade Federal de Santa Maria, 2010. http://repositorio.ufsm.br/handle/1/4041.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorBone defects due to trauma, postoperative and mutilating surgery complications, associated to removal of neoplasia, are part of the routine of hospitals and veterinary clinics. Bone grafts, within all their variants, represent the main viable alternative in the structural correction of great bone losses. Currently, the search for alternatives to correct these problems and the great potential of cellular therapy, have led numerous researchers to ingress into this line of study. The present work aimed to evaluate the influence of the hydration of bone implants conserved in glycerin 98% over their biomechanical resistance; the viability of a bone marrow harvesting protocol, for application in the clinical surgical routine; and the effect of intralesional application of bone marrow mononuclear cell fraction, over the consolidation of graft-host interface of dogs submitted to segmental bone grafting, with bone implants conserved in glycerin 98%. This research was developed in two phases. The first, ex-vivo, in which 108 bone fragments conserved in glycerin 98% were separated in six different groups, according to hydration period, and later were submitted to axial load test for biomechanical resistance evaluation. The second phase, in-vivo, in which 20 mongrel dogs, with mean weight of 13kg, were divided in four different groups according to the type of graft employed and with or without application of bone marrow mononuclear cell fraction. All animals were submitted to a bone marrow harvesting protocol, obtaining a final volume of 5ml kg-1 of body weight. The collected bone marrow was analyzed by means of myelogram and later submitted to isolation of the mononuclear cell fraction by a technique already affirmed in the literature. A diaphyseal femoral bone defect was created and repaired with the same removed segment (groups I and III) or with a bone segment conserved in glycerin 98% (groups II and IV). The bone marrow mononuclear cell fraction, after isolation, was injected via intralesional route in dogs of the treated groups (I and II), whereas the control group (III and IV) received an injection of the same volume, however, of 0.9% sodium chloride solution. The bone consolidation progress of the graft-host interfaces was followed by serial radiographic exams up to 90 days after surgical intervention, whereas the presence of mononuclear cells was followed up to seven days after implantation, by detection of Qtracker-665 nanocrystal fluorescence, used as cell marker. According to the results obtained, it can be concluded that: hydration of bone implant conserved in glycerin 98% does not produce statistically significant alterations in the biomechanical resistance of cortical bone for the different evaluated times. However, the bone mineral density has a close relationship with this property; bone marrow harvesting protocol with reduced volume of 5ml kg-1 of body weight, obtained from different long bones, proved to be adequate for isolation of mononuclear cell fraction and for obtaining a cell button with adequate number of cells and high viability, essential for the success of its therapeutic application; the consolidation of proximal and distal graft-host interfaces at 90 days after surgery no showed clinical and radiographic difference in the groups control and treated with bone marrow mononuclear cell fraction. Nevertheless, it cannot be confirmed that the cellular therapy used in this study is not an effective bone healing adjuvant, as it is believed that the restriction of load deposition on the focus of the fracture, achieved by reduced postoperative exercise, has influenced directly on the result of the consolidation.
As falhas ósseas decorrentes de trauma, complicações pós-operatórias e cirurgias mutilantes, associadas à remoção de neoplasias, fazem parte da rotina dos hospitais e clínicas veterinárias. Os enxertos ósseos, dentre todas as suas variantes, representam a principal alternativa viável na correção estrutural de grandes perdas ósseas. Na atualidade, a busca por alternativas para corrigir estes problemas e o grande potencial da terapia celular, tem levado inúmeros pesquisadores a ingressar nesta linha de estudo. No presente trabalho, buscou-se avaliar a influência da hidratação de implantes ósseos conservados em glicerina 98% sobre a resistência biomecânica dos mesmos; a viabilidade de um protocolo de colheita de medula óssea, para aplicação na rotina clínico-cirúrgica; e o efeito da aplicação intralesional da fração de células mononucleares da medula óssea, sobre a consolidação da interface enxerto-hospedeiro de cães submetidos à enxertia óssea segmentar, com implantes ósseos conservados em glicerina 98%. Esta pesquisa foi desenvolvida em duas fases. A primeira, ex-vivo, onde 108 fragmentos ósseos conservados em glicerina 98% foram separados em seis diferentes grupos, de acordo com o período de hidratação, sendo posteriormente submetidos a teste de compressão axial para avaliação de sua resistência biomecânica. A segunda fase, in-vivo, onde 20 cães sem raça definida e peso médio de 13kg, foram separados em quatro diferentes grupos de acordo com o tipo de enxerto empregado e com a aplicação ou não da fração de células mononucleares da medula óssea. Todos os animais foram submetidos a um protocolo de colheita de medula óssea, obtendo-se um volume final de 5ml kg-1 de peso corporal. A medula óssea colhida foi analisada por meio de mielograma e posteriormente submetida ao isolamento da fração de células mononucleares por técnica já consagrada na literatura. Um defeito ósseo femoral diafisário foi criado e reparado com o próprio segmento removido (grupos I e III) ou com um segmento ósseo conservado em glicerina 98% (grupos II e IV). A fração de células mononucleares da medula óssea, após isolamento, foi injetada por via intralesional nos cães dos grupos tratados (I e II), enquanto os grupos controle (III e IV) receberam a injeção do mesmo volume, porém, de solução de cloreto de sódio a 0,9%. A progressão da consolidação óssea das interfaces enxerto-hospedeiro foi acompanhada por exames radiográficos seriados até os 90 dias após a intervenção cirúrgica, enquanto a presença das células mononucleares, até os primeiros sete dias após a implantação, foi acompanhada pela detecção da fluorescência do nanocristal Qtracker-665, utilizado como marcador celular. De acordo com os resultado obtidos, pode-se concluir que: a hidratação do implante ósseo conservado em glicerina 98%, não produz alteração estatisticamente significativa na resistência biomecânica do osso cortical para os diferentes tempos avaliados. Contudo, a densidade mineral óssea possui estreita relação com esta propriedade; O protocolo de colheita de medula óssea em volume reduzido a 5ml kg-1 de peso corporal, obtidos de diferentes ossos longos, demonstrou-se adequado para isolamento da fração de células mononucleares e obtenção de um botão celular com adequado número de células e alta viabilidade, essenciais ao sucesso de sua aplicação terapêutica; a consolidação das interfaces enxerto-hospedeiro proximal e distal aos 90 dias após a cirurgia não apresentou diferença clínica e radiográfica entre os grupos controle e tratados com a fração de células mononucleares da medula óssea. Porém, não se pode afirmar que a terapia celular empregada neste estudo, não seja bom adjuvante da cicatrização óssea, pois se acredita, que a restrição na deposição de carga no foco de fratura, proveniente do reduzido exercício pós-operatório, tenha influenciado diretamente no resultado da consolidação.
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Kalová, Miroslava. "Deformačně napěťová analýza proximálního femuru s dříkem endoprotézy a zlomeninou". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230299.
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This work is focused on a solving of problems regarding a total hip replacement with a fractured femur. The fracture is located in the distal end of the total joint replacement stem and the fracture is spreading in the proximal direction on the boundary of the bone and cement. A proximal part of femur is reinforced by fixing tape. There is also briefly described how computer models were carried out. Furthermore a stress - strain analysis of solved system has been performed in this work. The solution was realized using the finite element method in computational program ANSYS Workbench. Different variants with change of a fracture range and number of fixing tapes were considered during the solving. Stress - strain analysis shows that due a application of fourth fixing tape occurs lowering of main stresses values in the femur in fracture region. Simultaneously occurs a reduction of Equivalent stress values on a distal part of stem.
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Santos, Tatiane Souza dos [UNESP]. "Efeito de fitases de origem bacteriana no desempenho e qualidade óssea de frangos de corte". Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/140152.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Este estudo objetivou avaliar o efeito de três fitases comerciais derivadas da Escherichia coli, em dietas com níveis reduzidos de fósforo disponível, sobre o desempenho, fosfatase alcalina e ácida no soro, cálcio e fósforo no plasma e nos parâmetros ósseos (densitometria óssea, resistência óssea e cinzas) de frangos de corte aos 35 dias de idade. Dois mil e cem pintos machos de um dia de idade da linhagem Cobb®500 foram alojados em 70 boxes em delineamento experimental inteiramente casualizado em esquema fatorial, criados até 35 dias de idade dividido em fase inicial (I) e fase de crescimento (C). Nos tratamentos Controle positivo*(CP*) e Controle negativo*(CN*) foi praticada a valorização nutricional da fitase preconizada pelos fabricantes (0,12% Pd) em relação aos tratamentos Controle positivo (CP) e Controle negativo (CN). O esquema fatorial foi 2x4+2: dois níveis de fósforo disponível (Pd) (CP* - 0,33% (I) e 0,28% (C)) e (CN* - 0,23% (I) e 0,18% (C)) × fitases (A, B, C, ausente) + CP (0,45 (I) e 0,40% (C) Pd, sem fitase) e CN (redução de 0,10% de Pd: 0,35 (I) e 0,30% (C) Pd, sem fitase) totalizando 10 tratamentos com sete repetições. A ausência de fitase na dieta CN* promoveu os piores resultados para desempenho e qualidade óssea, além de elevar o nível de fosfatase alcalina e cálcio no sangue como resposta ao baixo nível de fósforo disponível na dieta. A inclusão de fitases nas dietas CP* melhorou o desempenho, com maior disponibilidade de minerais para o desenvolvimento ósseo. Desta forma, a densidade óssea da tíbia e do fêmur aumentaram, proporcionando ossos mais resistentes e com maior porcentagem de cinzas. Recomenda-se, quando da utilização das fitases para frangos de corte, utilizar apenas a valorização nutricional da enzima (-0,12% Pd), sem redução adicional de fósforo disponível nas dietas.
This study aimed to evaluate the effect of three commercial phytases derived from Escherichia coli, in diets with reduced levels of available phosphorus, on performance, alkaline and acid phosphtases in serum, calcium and phosphorus in plasma and bone parameters (bone density, bone strength and ash) of broilers at 35 d old. Two thousand one hundred male Cobb®500 broilers were housed in 70 pens in a completely randomized design in factorial arrangement, reared to 35 d old divided into starter phase (I) and the grower phase (G). In treatments positive control* (PC*) and negative control*(NC*) was practiced nutritional value of phytase recommended by the manufacturer (0.12% aP) in relation to positive control (PC) and negative control (NC) treatments. The factorial design was 2x4+2: two levels of available phosphorus (aP) (PC* - 0.33% (S) and 0.28 % (G)) and (NC* - 0.23% (S) and 0.18% (G)) × phytases (A, B, C, without) + PC (0.45 (S) and 0.40% (G) aP without phytase) and NC (decrease of 0.10 of aP: 0.35 (S) and 0.30% (G) aP without phytase) for a total 10 treatments with seven replicates. The absence of phytase in the diet NC* promoted the worst results for performance and bone quality, and increased the level of alkaline phosphatase and calcium in the blood in response to low levels of available phosphorus in diet. The inclusion of phytase in diets PC* improve the performance and increased availability of minerals for bone development. Thus, increased the bone density of the tibia and femur, bone strenght and bone ash. It is concluded that the inclusion phytase in diets PC* was sufficient to ensure good performance and bone quality. It is recommended, while the use of phytases for broiler use only the nutritional value of phytase (-0.12% aP) without additional reduction of available phosphorus in the diets.
FAPESP: 2014/27175-8
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Santos, Tatiane Souza dos. "Efeito de fitases de origem bacteriana no desempenho e qualidade óssea de frangos de corte". Botucatu, 2016. http://hdl.handle.net/11449/140152.
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Orientador: José Roberto SartoriResumo: Este estudo objetivou avaliar o efeito de três fitases comerciais derivadas da Escherichia coli, em dietas com níveis reduzidos de fósforo disponível, sobre o desempenho, fosfatase alcalina e ácida no soro, cálcio e fósforo no plasma e nos parâmetros ósseos (densitometria óssea, resistência óssea e cinzas) de frangos de corte aos 35 dias de idade. Dois mil e cem pintos machos de um dia de idade da linhagem Cobb®500 foram alojados em 70 boxes em delineamento experimental inteiramente casualizado em esquema fatorial, criados até 35 dias de idade dividido em fase inicial (I) e fase de crescimento (C). Nos tratamentos Controle positivo*(CP*) e Controle negativo*(CN*) foi praticada a valorização nutricional da fitase preconizada pelos fabricantes (0,12% Pd) em relação aos tratamentos Controle positivo (CP) e Controle negativo (CN). O esquema fatorial foi 2x4+2: dois níveis de fósforo disponível (Pd) (CP* - 0,33% (I) e 0,28% (C)) e (CN* - 0,23% (I) e 0,18% (C)) × fitases (A, B, C, ausente) + CP (0,45 (I) e 0,40% (C) Pd, sem fitase) e CN (redução de 0,10% de Pd: 0,35 (I) e 0,30% (C) Pd, sem fitase) totalizando 10 tratamentos com sete repetições. A ausência de fitase na dieta CN* promoveu os piores resultados para desempenho e qualidade óssea, além de elevar o nível de fosfatase alcalina e cálcio no sangue como resposta ao baixo nível de fósforo disponível na dieta. A inclusão de fitases nas dietas CP* melhorou o desempenho, com maior disponibilidade de minerais para o desenvolviment... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: This study aimed to evaluate the effect of three commercial phytases derived from Escherichia coli, in diets with reduced levels of available phosphorus, on performance, alkaline and acid phosphtases in serum, calcium and phosphorus in plasma and bone parameters (bone density, bone strength and ash) of broilers at 35 d old. Two thousand one hundred male Cobb®500 broilers were housed in 70 pens in a completely randomized design in factorial arrangement, reared to 35 d old divided into starter phase (I) and the grower phase (G). In treatments positive control* (PC*) and negative control*(NC*) was practiced nutritional value of phytase recommended by the manufacturer (0.12% aP) in relation to positive control (PC) and negative control (NC) treatments. The factorial design was 2x4+2: two levels of available phosphorus (aP) (PC* - 0.33% (S) and 0.28 % (G)) and (NC* - 0.23% (S) and 0.18% (G)) × phytases (A, B, C, without) + PC (0.45 (S) and 0.40% (G) aP without phytase) and NC (decrease of 0.10 of aP: 0.35 (S) and 0.30% (G) aP without phytase) for a total 10 treatments with seven replicates. The absence of phytase in the diet NC* promoted the worst results for performance and bone quality, and increased the level of alkaline phosphatase and calcium in the blood in response to low levels of available phosphorus in diet. The inclusion of phytase in diets PC* improve the performance and increased availability of minerals for bone development. Thus, increased the bone density of the ti... (Complete abstract click electronic access below)
Mestre
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Grande, García Eduardo [Verfasser], Ernst [Akademischer Betreuer] Rank i Rainer H. H. [Akademischer Betreuer] Burgkart. "Double Experimental Procedure for Model-Specific Finite Element Analysis of the Human Femur and Trabecular Bone / Eduardo Grande García. Gutachter: Ernst Rank ; Rainer H. H. Burgkart. Betreuer: Ernst Rank". München : Universitätsbibliothek der TU München, 2013. http://d-nb.info/1034420739/34.
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Le, Corroller Thomas. "Altérations de la structure osseuse de l'extrémité proximale du fémur : Analyse en imagerie médicale, étude biomécanique, et application à la prédiction du risque fracturaire". Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4010.
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La fracture ostéoporotique du col fémoral et la coxarthrose constituent aujourd'hui deux enjeux majeurs de santé publique chez les sujets âgés. L'ostéoporose est définie par une diminution de la masse osseuse et une altération de la structure osseuse. La coxarthrose d'autre part associe la perte progressive du cartilage d'encroûtement articulaire, une sclérose osseuse sous-chondrale, des géodes sous-chondrales, et des ostéophytes marginaux. Bien qu'une masse osseuse élevée semble prédisposer à l'arthrose, les relations métaboliques et biomécaniques entre ostéoporose et coxarthrose sont complexes. L'évaluation de l'architecture osseuse de l'extrémité proximale du fémur est un des enjeux majeurs de recherche actuels visant à la caractérisation des modifications du tissu osseux liées au vieillissement. Notre travail de thèse s'est inscrit dans un projet pluridisciplinaire de recherche sur les altérations de la structure osseuse de l'extrémité proximale du fémur, reposant sur une analyse en imagerie médicale et une étude biomécanique de cette région anatomique fondamentaleFracture of the proximal femur and hip osteoarthritis are nowadays a major public health problem in elderly persons. The current definition of osteoporosis is a low bone mass associated with microarchitecture deterioration. On the other hand, osteoarthritis corresponds to progressive articular cartilage loss, subchondral bone sclerosis, subchondral bone cysts, and marginal osteophytes. Although a higher bone mass may increase the risk of osteoarthritis, osteoporosis and hip osteoarthritis present a complex metabolic and biomechanical relationship. The proximal femur architectural evaluation and characterization of age-related osseous alterations are currently one of the main challenges in bone and mineral research. Our work was based on a multidisciplinary project which aimed at evaluating the age-related structural deterioration of the proximal femur using medical imaging and biomechanical testing in this crucial anatomical region