1,333 research outputs found

    Estimation of sex from scapulae measurements in a Western Australian population

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    Identifying the sex of unknown individual remains is the first task an anthropologist undertakes towards creating a biological profile. Most bones within the human skeleton have been analysed and determined to be sexually dimorphic. As such, forensic anthropometric standards have been developed in order to aid investigators in the estimation of sex of an individual. The issue investigators have is the lack of population-specific standards available across geographically diverse populations. Similarly, there is a lack of population-specific knowledge pertaining to bones not usually examined in an investigation. This review analyses and critiques the knowledge associated to the estimation of sex using the scapula. It was determined that the scapula is a highly dimorphic bone with many populations having developed population-specific standards in order to aid investigators. In turn, the literature has determined that the use of Computer Tomographic (CT) scans in lieu of physical specimens is a reliable and accurate substitute for populations relying primarily on the use of digital skeletal depositories to store data. In conjunction, it has been determined that despite the scapula exhibiting small bilateral variations within an individual, pertaining to the estimation of sex the differences are negligible. As such, either the left or right scapulae can be analysed in order to derive forensic anthropometric standards. Specifically, this review will analyse the data pertaining to the estimation of sex in a Western Australian population, and the gaps in the knowledge regarding the scapula will be discussed

    Computer modelling of the development of the trabecular architecture in the human pelvis

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    The influence of mechanical loading upon bone growth and remodelling has been widely studied. It has been suggested that functional bone growth is evident within the human adult pelvis, where the internal trabecular structure is purported to align to the principal strain trajectories induced during bipedal locomotion. Ontogenetic studies of the juvenile pelvis have observed that trabecular bone growth becomes progressively ordered from  an initial randomised patterning. This has lead to theories linking the gradual structural optimisation of  trabecular bone to the mechanical forces associated with the development of juvenile locomotion. However, recent studies have observed partially optimised trabecular structures within the human fetal and neonatal  pelvis, in contrast to previous observations. The possible genetic and mechanical factors which cause the in utero formation of these trabecular structures, which are usually associated with a weight bearing function,  remains unknown. Therefore, this thesis aimed to investigate the influence of the mechanical strains associated with juvenile movements, upon the growth of pelvic trabecular bone.Biomechanical analyses were performed on digitised models of juvenile pelvic specimens belonging to the  Scheuer collection. Digitised models of a prenatal, 1 year, 8 year and 19 year old pelvis were constructed  through processing mircocomputed tomography scan data. A geometric morphometric reconstruction technique was devised which enabled the creation of hemi-pelvic models from originally disarticulated bone specimens. This reconstruction technique was validated through a close morphological comparison between a  reconstructed hemi-pelvis, and its originally articulated CT data. The muscular and joint forces associated with  in utero movements and bipedal locomotion, were computed through musculoskeletal simulations. A prenatal  musculoskeletal model was constructed to replicate the in utero mechanical environment, and simulated  interactions between the fetal leg and the womb wall. The forces associated with bipedal locomotion were  evaluated through analysis of a pre-defined subject-specific musculoskeletal model. An attempt was made to  validate the modelling technique of altering generic musculoskeletal models to create subject-specific  representations. However, comparisons between computed and experimentally recorded muscle activities  proved inclusive, although this was attributed to uncertainties in the accuracy of the experimental data. A series of finite element analyses computed the strain distributions associated with the predicted musculoskeletal  loading. A range of load regimes were applied to each juvenile pelves, and were based upon the computed  musculoskeletal forces and the maximum isometric force capabilities of the pelvic muscles. However, despite  the differences between the applied load regimes, the predicted von Mises and compressive strain distributions  displayed similarities for all the ages analysed. All the predicted distributions were characterised  by high strains within the inferior ilium, which correlated to a region of high trabecular organisation. The high  strain magnitudes then travelled superiorly in either a gradual or rapid dissipation, both of which did not  produce a distribution which correlated to the pelvic trabecular histomorphometry. Therefore, no strain  distribution was predicted with divergence of the inferior strains to the anterior and posterior regions of the ilium,  as observed with the trabecular trajectories within the pelvis.As the predicted von Mises and compressive strain distributions failed to match the complete iliac trabecular  histomorphometry, it was suggested that the in utero formation of partially optimised trabecular growth is  possibly due to generic factors. This thesis provided initial investigations into the musculoskeletal and  mechanical loading of the juvenile pelvis, although future work is required to develop the applied modelling  techniques to fully determine the influence of the mechanical strains

    Coronectomy of deeply impacted lower third molar : incidence of outcomes and complications after one year follow-up

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    Objectives: The purpose of present study was to assess the surgical management of impacted third molar with proximity to the inferior alveolar nerve and complications associated with coronectomy in a series of patients undergoing third molar surgery. Material and Methods: The position of the mandibular canal in relation to the mandibular third molar region and mandibular foramen in the front part of the mandible (i.e., third molar in close proximity to the inferior alveolar nerve [IAN] or not) was identified on panoramic radiographs of patients scheduled for third molar extraction. Results: Close proximity to the IAN was observed in 64 patients (35 females, 29 males) with an impacted mandibular third molar. Coronectomy was performed in these patients. The most common complication was tooth migration away from the mandibular canal (n = 14), followed by root exposure (n = 5). Re-operation to remove the root was performed in cases with periapical infection and root exposure. Conclusions: The results indicate that coronectomy can be considered a reasonable and safe treatment alternative for patients who demonstrate elevated risk for injury to the inferior alveolar nerve with removal of the third molars. Coronectomy did not increase the incidence of damage to the inferior alveolar nerve and would be safer than complete extraction in situations in which the root of the mandibular third molar overlaps or is in close proximity to the mandibular canal

    Geometric morphometric analysis on the pelvic bone by race, sex, and age

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    Geometric Morphometric technique is one of the wide techniques has been used by anthropologists in the identification of biological specimens such as bones. The pelvic bone has played a significant role in the human system such as locomotor behavior and baby carrier for females during pregnancy period. By analysing the geometric morphometric method on pelvic bone, the identification of bone such as race, sex, and age, may be determined. Using PACS database, 58 bones were selected randomly to assess sex, age, and race. After that these random image were cleaned and cut using Meshmixer software. Using Institute for Data Analysis and Visualization (IDAV), the landmark of the pelvic bone was selected and ready to analyse by MorphoJ software. There were three statistical analysis that were done which were procrutes ANOVA, principles component analysis (PCA), and canonical variate analysis (CVA). Based on these three statistical analysis, it is found that there is a cluster was shown which is age group of 10 whom from age 1 to 10 years old, 51 to 60 years old and 61 to 70 years old. These cluster were obviously shown compared to other group such as sex and age because of physiology and locomotor changes. There is interference were shown in the other group such as sex, race and other group of age. The interference of group causing the difficulty to analyse the graph

    Clinical observation of diminished bone quality and quantity through longitudinal HR-pQCT-derived remodeling and mechanoregulation.

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    High resolution peripheral quantitative computed tomography (HR-pQCT) provides methods for quantifying volumetric bone mineral density and microarchitecture necessary for early diagnosis of bone disease. When combined with a longitudinal imaging protocol and finite element analysis, HR-pQCT can be used to assess bone formation and resorption (i.e., remodeling) and the relationship between this remodeling and mechanical loading (i.e., mechanoregulation) at the tissue level. Herein, 25 patients with a contralateral distal radius fracture were imaged with HR-pQCT at baseline and 9-12 months follow-up: 16 patients were prescribed vitamin D3 with/without calcium supplement based on a blood biomarker measures of bone metabolism and dual-energy X-ray absorptiometry image-based measures of normative bone quantity which indicated diminishing (n = 9) or poor (n = 7) bone quantity and 9 were not. To evaluate the sensitivity of this imaging protocol to microstructural changes, HR-pQCT images were registered for quantification of bone remodeling and image-based micro-finite element analysis was then used to predict local bone strains and derive rules for mechanoregulation. Remodeling volume fractions were predicted by both average values of trabecular and cortical thickness and bone mineral density (R2 > 0.8), whereas mechanoregulation was affected by dominance of the arm and group classification (p < 0.05). Overall, longitudinal, extended HR-pQCT analysis enabled the identification of changes in bone quantity and quality too subtle for traditional measures

    Focal osteoporosis defects play a key role in hip fracture

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    BACKGROUND\textbf{BACKGROUND}: Hip fractures are mainly caused by accidental falls and trips, which magnify forces in well-defined areas of the proximal femur. Unfortunately, the same areas are at risk of rapid bone loss with ageing, since they are relatively stress-shielded during walking and sitting. Focal osteoporosis in those areas may contribute to fracture, and targeted 3D measurements might enhance hip fracture prediction. In the FEMCO case-control clinical study, Cortical Bone Mapping (CBM) was applied to clinical computed tomography (CT) scans to define 3D cortical and trabecular bone defects in patients with acute hip fracture compared to controls. Direct measurements of trabecular bone volume were then made in biopsies of target regions removed at operation. METHODS\textbf{METHODS}: The sample consisted of CT scans from 313 female and 40 male volunteers (158 with proximal femoral fracture, 145 age-matched controls and 50 fallers without hip fracture). Detailed Cortical Bone Maps (c.5580 measurement points on the unfractured hip) were created before registering each hip to an average femur shape to facilitate statistical parametric mapping (SPM). Areas where cortical and trabecular bone differed from controls were visualised in 3D for location, magnitude and statistical significance. Measures from the novel regions created by the SPM process were then tested for their ability to classify fracture versus control by comparison with traditional CT measures of areal Bone Mineral Density (aBMD). In women we used the surgical classification of fracture location ('femoral neck' or 'trochanteric') to discover whether focal osteoporosis was specific to fracture type. To explore whether the focal areas were osteoporotic by histological criteria, we used micro CT to measure trabecular bone parameters in targeted biopsies taken from the femoral heads of 14 cases. RESULTS\textbf{RESULTS}: Hip fracture patients had distinct patterns of focal osteoporosis that determined fracture type, and CBM measures classified fracture type better than aBMD parameters. CBM measures however improved only minimally on aBMD for predicting any hip fracture and depended on the inclusion of trabecular bone measures alongside cortical regions. Focal osteoporosis was confirmed on biopsy as reduced sub-cortical trabecular bone volume. CONCLUSION\textbf{CONCLUSION}: Using 3D imaging methods and targeted bone biopsy, we discovered focal osteoporosis affecting trabecular and cortical bone of the proximal femur, among men and women with hip fracture.Arthritis Research UK (grant no. ARC17822) and Cambridge National Institute for Health Research (NIHR) Biomedical Research Centre

    Body Mass Estimation from the Human Skeleton

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    The established methods for estimating average body mass from the skeleton are of two types: biomechanical and morphometric. Neither technique currently addresses the extremes of body mass (e.g. emaciation or obesity). The goal of this research is to explore several different biomechanical methods, using data collected from high resolution computed tomographic scans and macroscopic analysis of 150 known modern individuals from the William M. Bass Donated Skeleton Collection at the University of Tennessee, Knoxville. This research will review the biomechanics of human gait and the biomechanical accommodations that occur with increased obesity and load bearing. The analysis will include cross-sectional geometry of the human femur at five locations along the diaphysis, bone mineral density scans of the proximal femur and a macroscopic evaluation of degenerative changes of the articulations of the spine, hip, knee and foot. The best single indicator of body mass for both males and females is the cross-sectional area of the proximal femur and BMD. By using pathologies combined, an accuracy rate of 87% for predicting obesity was achieved using a classification tree with sexes pooled. Furthermore, severe obesity has such a profound effect on the human skeleton as to leave a suite of traits affecting the load bearing elements of the lower limb and vertebral column

    Development of assessment in hip arthroplasty review

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    AbstractThis thesis describes the development of criteria in hip arthroplasty review. The insertion of a hip replacement brings relief from pain and improved function but the artificial joint does not last indefinitely. Periodic review provides the opportunity to assess the state of the joint in order to identify a failing hip arthroplasty.A literature search was conducted on the subject of failing hip arthroplasty and the findings are summarised. There was a lack of standardisation of methodology but an emphasis on the need for review because of the commonly asymptomatic nature of a failing hip arthroplasty.The review process has traditionally been completed by medical members of the orthopaedic team but there has been a recent change to include non-medical health professionals in this work. A lack of formalised educational programmes has led to innovative ways of achieving the required competency, and one such method is described for the development of a skill in interpretation of x-ray images of hip replacements.Radiographic assessment is an important component of hip arthroplasty review and includes the measurement of osteolytic lesions, a phenomenon caused by the wear particles produced from the articulating surfaces of the artificial joint. A simple, clinical tool was developed to measure these irregularly shaped lesions and the testing of the tool is described.Finally, a clinical study was conducted to explore the association between changes on a patient reported outcome measure and x-ray changes over the same period of time. The patients had all received a hip replacement approximately seven years earlier (mid-term) and so were at a stage when signs of deterioration of the hip joint were likely to appear. This thesis makes a contribution to the scientific base of arthroplasty review. It demonstrates a training model for non-medical health professions to acquire the skills needed to conduct the review. It employs basic research to develop a simple and reliable tool for use in the clinical situation. It shows that, for patients reviewed at mid-term, it is essential to include an x-ray as well as a joint-specific patient reported outcome measure. This information is important for future service planning and development of practitioners, and is of benefit to patients through adding to the evidence about the criteria for arthroplasty review

    In vivo morphometric and mechanical characterization of trabecular bone from high resolution magnetic resonance imaging

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    La osteoporosis es una enfermedad ósea que se manifiesta con una menor densidad ósea y el deterioro de la arquitectura del hueso esponjoso. Ambos factores aumentan la fragilidad ósea y el riesgo de sufrir fracturas óseas, especialmente en mujeres, donde existe una alta prevalencia. El diagnóstico actual de la osteoporosis se basa en la cuantificación de la densidad mineral ósea (DMO) mediante la técnica de absorciometría dual de rayos X (DXA). Sin embargo, la DMO no puede considerarse de manera aislada para la evaluación del riesgo de fractura o los efectos terapéuticos. Existen otros factores, tales como la disposición microestructural de las trabéculas y sus características que es necesario tener en cuenta para determinar la calidad del hueso y evaluar de manera más directa el riesgo de fractura. Los avances técnicos de las modalidades de imagen médica, como la tomografía computarizada multidetector (MDCT), la tomografía computarizada periférica cuantitativa (HR-pQCT) y la resonancia magnética (RM) han permitido la adquisición in vivo con resoluciones espaciales elevadas. La estructura del hueso trabecular puede observarse con un buen detalle empleando estas técnicas. En particular, el uso de los equipos de RM de 3 Teslas (T) ha permitido la adquisición con resoluciones espaciales muy altas. Además, el buen contraste entre hueso y médula que proporcionan las imágenes de RM, así como la utilización de radiaciones no ionizantes sitúan a la RM como una técnica muy adecuada para la caracterización in vivo de hueso trabecular en la enfermedad de la osteoporosis. En la presente tesis se proponen nuevos desarrollos metodológicos para la caracterización morfométrica y mecánica del hueso trabecular en tres dimensiones (3D) y se aplican a adquisiciones de RM de 3T con alta resolución espacial. El análisis morfométrico está compuesto por diferentes algoritmos diseñados para cuantificar la morfología, la complejidad, la topología y los parámetros de anisotropía del tejido trabecular. En cuanto a la caracterización mecánica, se desarrollaron nuevos métodos que permiten la simulación automatizada de la estructura del hueso trabecular en condiciones de compresión y el cálculo del módulo de elasticidad. La metodología desarrollada se ha aplicado a una población de sujetos sanos con el fin de obtener los valores de normalidad del hueso esponjoso. Los algoritmos se han aplicado también a una población de pacientes con osteoporosis con el fin de cuantificar las variaciones de los parámetros en la enfermedad y evaluar las diferencias con los resultados obtenidos en un grupo de sujetos sanos con edad similar.Los desarrollos metodológicos propuestos y las aplicaciones clínicas proporcionan resultados satisfactorios, presentando los parámetros una alta sensibilidad a variaciones de la estructura trabecular principalmente influenciadas por el sexo y el estado de enfermedad. Por otra parte, los métodos presentan elevada reproducibilidad y precisión en la cuantificación de los valores morfométricos y mecánicos. Estos resultados refuerzan el uso de los parámetros presentados como posibles biomarcadores de imagen en la enfermedad de la osteoporosis.Alberich Bayarri, Á. (2010). In vivo morphometric and mechanical characterization of trabecular bone from high resolution magnetic resonance imaging [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/8981Palanci

    Pelvic kinematics as confounding factor for cam hip impingement

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    The purpose of this thesis was to explore a range of biomechanical factors linked to the development of symptoms and potentially early onset hip OA in people with cam hip impingement. This was achieved through shape analysis on 3D bone models (segmented from medical images), and motion analysis performed during walking and squatting. Following ethical approval, kinematic and morphological variables were obtained from 19 pre-operative hip impingement patients and 18 healthy controls, and these were compared between groups. Patients demonstrated reduced neck-shaft-angles (-6.0°, p<.01) and increased anterior pelvic tilt during gait (+3.2°, p=.04) which are thought to predispose to impingement by decreasing the proximity between the cam and acetabular rim and making abutment more likely. The transverse pelvic plane is used to measure pelvic tilt during motion analysis, it is therefore interesting that the angle between the transverse and anterior pelvic plane is increased (+4.6°, p=.03) in patients, emphasising that the interplay between shape and function is a priority for further research. Avoidance of hip extension (-5.9°, p<.01) was also observed, which could be a compensatory mechanism to prevent further damages to the hip. Furthermore, large cams are thought to act as a mechanical constraint and limit rotation movement allowed within the acetabulum, as demonstrated by reduced peak hip internal rotation (during squat, -8.5°, p=.03). Controls were regrouped based on morphology to allow comparison between asymptomatic (CAM-; n=11) and symptomatic (CAM+, n=16) cams. Symptomatic cams have an increased width (+41.4°, p<.01), and start more superiorly (-29.4°, p<.01). Increased sagittal pelvic mobility (e.g. during a squat; -11.2° for CAM+, p<.01) is thought to be protective against hip impingement symptoms, as during high flexion angles the pelvic tilts backwards reducing the risk of abutment. These findings highlight the need to establish thresholds taking confounding factors into account.Open Acces
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