The likelihood of a given bone fracturing atraumatically is difficult to assess.. A number of factors - age, frequency of falling, cushioning by overlying tissues, protective reactions - as well as bone strength determine fracture risk. The interrelationships between these factors make it hard to evaluate the effect of any one variable in a study. The most common method of assessing bone strength is to use the surrogate method of bone mineral content (BMC) or bone mineral density (BMD). The architectural breakdown of the trabeculae, the mineral "mesh" which makes up bone, is a little-studied factor which may help to better predict fracture. In this thesis, the results of quantitative measurements of trabecular architecture, BMD, and strength of femoral heads scavenged from hip replacement surgery will be presented. This is intended to illuminate the relationships between bone strength, bone density, and trabecular architecture. / Thesis / Master of Science (MSc)

Background: Hip fractures are a major health problem in Canada, and two main contributors to hip fracture are weak bone strength and fall. Weak muscles also negatively affect bone strength and increase the likelihood of falling. Advanced imaging techniques, such as magnetic resonance imaging (MRI), offer in vivo measurement of bone strength and muscle area at the proximal femur. However, it is not known if MRI-based measurements of bone and muscle properties are repeatable (i.e. precise). Methods: The femoral neck and shaft of 14 healthy participants were scanned three times, using a 1.5T MRI with repositioning between scans. Boundaries of the femoral neck, shaft and four muscle groups were delineated semi-automatically. Geometrical and strength properties of bone and area of muscle groups were determined based on segmented images. The short-term precision errors (root mean square coefficient of variation; CVrms%) between the repeated measures were calculated accordingly. Results: MRI-based measures of bone geometry and strength and muscle area at the proximal femur demonstrated in vivo precision errors < 7.6%. The average CVrms% for bone measures and muscle area were less than 4% and 2.5% respectively. Higher CVrms% (e.g. average: 4.8%) was obtained for bone strength properties. Conclusion: This is the first study to evaluate the in vivo performance of MRI on application to the proximal femur and surrounding muscles. Results demonstrate that MRI is a promising non-ionizing technique that offers precise measures of bone and muscle at the proximal femur.

Made available in DSpace on 2014-08-13T14:50:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-05-27Bitstream added on 2014-08-13T18:00:58Z : No. of bitstreams: 1 000749636.pdf: 644023 bytes, checksum: 4cc0b5b973664de374d7089a8baa2c9e (MD5) / O trabalho teve por objetivos avaliar cães submetidos à ostectomia unilateral da cabeça femoral, por meio de avaliação clínica padrão e locomovendo-se em plataforma de pressão. A hipótese é que esses animais tenham alterações cinéticas e têmporo-espaciais decorrentes do procedimento cirúrgico, que podem ser detectadas por índice de simetria. Foram utilizados 30 cães divididos em dois grupos equitativos: Grupo 1 - animais hígidos; Grupo 2 – animais submetidos à ostectomia unilateral da cabeça e colo femorais, por meio de acesso craniolateral e sem interposição muscular. A velocidade foi mantida entre 0,9 e 1,1 m/s e a aceleração entre -0,15 e 0,15 m/s2. Foram determinados o Pico de Força Vertical, Impulso Vertical, duração do ciclo de locomoção, duração da fase de apoio, duração da fase de balanço, comprimento do passo e porcentagem de distribuição de peso. O Índice de Simetria (IS) foi calculado entre os membros para cada variável dos grupos 1 e 2. Na sequência, os Índices de Simetrias foram comparados entre Grupos. O resultado funcional (Grupo 2) foi considerado excelente em 10 animais, bom em quatro e razoável em um caso. O membro operado estava encurtado e a medida da circunferência da coxa foi menor comparado ao membro contralateral. A extensão do quadril estava limitada. Ao exame radiográfico foi observado deslocamento proximal do fêmur em todos os membros operados. Diferenças estatisticamente significantes foram observadas para os Índices de Simetria entre G1 e G2 em diversos parâmetros têmporo-espaciais. O Impulso Vertical foi estatisticamente significativo comparando o IS de G1 membro pélvico/membro torácico com G2 membro pélvico operado/membro torácico ipsilateral e membro pélvico operado/membro torácico diagonal. Foi possível concluir que cães com ostectomia unilateral da cabeça e colo femorais apresentam mudanças principalmente nos parâmetros têmporo-espaciais, as quais ... / The aim of this study was to evaluate dogs with unilateral femoral head and neck ostectomy through standard clinical evaluation and using a pressure-sensitive walkway. The hypothesis was that these dogs exhibit changes in kinetic and temporospatial parameters due to the surgical procedure that may detected by Symmetry Index (SI). Thirty dogs divided into two groups were used: G1 had 15 clinically healthy dogs; G2 had 15 dogs that underwent unilateral femoral head and neck ostectomy performed through access craniolateral and without muscle interposition. The velocity was maintained from 0.9-1.1 m/s and acceleration from -0.15 to 0.15 m/s2. Five valid trials were analyzed for each dog. The peak vertical force, vertical impulse, gait cycle time, stance time, swing time, stride length, and the percentage body weight distribution among the four limbs were determined. The Symmetry Index was calculated between limbs for each variable in G1 and G2. After this, Symmetry Indices were compared between Groups. Limb function (G2) was considered excellent in 10 dogs, good in four, and fair in one case. The operated limb was shortened and circumferential measurement of the thigh was lesser compared to contralateral limb. Hip extension was limited. In radiographic examination, displacement of the proximal femur was observed in all operated limbs. Statistical differences were observed for the Symmetry indices between G1 and G2 in several temporospatial parameters. Impulse was statistically different comparing SI of the G1 hind limb/forelimb with G2 operated hind limb/ipsilateral forelimb and G2 operated hind limb/diagonal forelimb. In conclusion, dogs with unilateral femoral head and neck ostectomy have changes mostly in temporospatial parameters that may be detected by SI, despite good functional results

Made available in DSpace on 2015-10-06T13:02:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-05-22. Added 1 bitstream(s) on 2015-10-06T13:19:37Z : No. of bitstreams: 1 000847770.pdf: 603210 bytes, checksum: 9378a25e0f01dd3c1f600007a516b9f2 (MD5) / Introdução: A lesão renal aguda (LRA) ocorre em 23% dos pacientes hospitalizados. É responsável por alta morbimortalidade e, ainda assim, não há um marcador precoce e acurado de diagnóstico. Pacientes idosos estão em risco e frequentemente desenvolvem LRA no pós-operatório de grandes cirurgias ortopédicas. Objetivos: Avaliar o biomarcador NGAL plasmático como preditor precoce de LRA no período pós-operatório de fratura de fêmur em idosos. Método: 57 pacientes idosos submetidos à operação de correção de fratura de fêmur foram estudados prospectivamente após 48 horas do pós-operatório. Amostras de sangue foram coletadas para análise de NGAL logo ao término da cirurgia, no período de 4 e 24 horas depois. Amostras da creatinina foram coletadas na admissão hospitalar, 24 e 48 horas no pós-operatório. Foi analisada a acurácia da molécula de NGAL para diagnóstico de LRA. Resultados: Dezesseis (28%) pacientes desenvolveram LRA e apresentaram valores mais elevados de NGAL no plasma com diferença estatística significativa. A análise da área sob a curva Receiving Operator Characteristic demonstrou em 4 horas valor de 0.799 (0.663 a 0.936, p< 0,001); em 24 horas valor de 0.805(0.665 a 0.946, p<0,001). Conclusão: A molécula de NGAL apresentou uma boa acurácia para predição de LRA quando medido após 4 e 24 horas do período pós-operatório / Introduction: Introduction: Acute kidney injury is common in hospitalized patients undergoing surgical procedures. It is responsible for a high mortality and yet, there is no early and reliable diagnostic marker. Elderly patients are at risk and often undergo orthopedic procedures as surgical repair of femur fractures. Objectives: To evaluate serum NGAL as a predictor of AKI in the postoperative correction of femur fractures in the elderly. Methodology: 56 elderly patients undergoing surgical repair of femoral fracture were studied prospectively for 48 hours postoperatively. Blood samples were collected for analysis of NGAL after surgery, 4 and 24 hours later. Creatinine measurements collected 24 and 48 hours postoperatively. Accuracy of NGAL was analyzed for diagnosis of acute kidney injury. Results: 16 (28.1%) of patients developed AKI and had significantly higher values of serum NGAL. In 4hours the AUROC = 0799 (0663-0936, p <0.001). In 24 hours the AUROC = 0.805 (0665-0946, p <0001). Conclusion: The molecule of NGAL showed good accuracy for prediction of AKI within 24 hours when measured after 04 hours and 24 hours postoperatively

Orientador: William Dias Belangero / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-08T02:22:20Z (GMT). No. of bitstreams: 1 Angelini_AlessandroJanson_D.pdf: 8473233 bytes, checksum: 3996290e908ef6f361b3a4bf25baf1d9 (MD5) Previous issue date: 2006 / Resumo: A partir de resultados de estudos mecânicos com a placa em onda, demonstrando sua maior rigidez em montagens com algum tipo de contato cortical, surge este estudo com o objetivo de analisar o desempenho desse tipo de placa no tratamento das fraturas de traço simples da diáfise do fêmur. Foram incluídos, retrospectivamente, 57 pacientes, consecutivos, tratados com a placa em onda com técnica de osteossíntese biológica, com seguimento mínimo de um ano de pós-operatório. Obteve-se índice de consolidação de 94,74% (54 em 57 pacientes) em tempo médio de 12,88 semanas. Conclui-se que o método pode ser considerado uma alternativa às hastes intramedulares, com índices de consolidação semelhantes / Abstract: Mechanical studies with wave plates, were a higher rigidity was shown in models with cortical contact, suggested a study to analyze the use of wave plate in femoral simple shaft fractures. A consecutive series of 57 patients treated with wave plates and biological internal fixation, and a minimal follow up of 1 year after surgery. Healing occurred in 94,74% (54 of 57 patients) with an average of 12 weeks. In conclusion, this method could be considered an alternative to intramedullary nailing, with similar success rates / Doutorado / Cirurgia / Doutor em Cirurgia

In 220 rabbits (65 mature and 155 immature) the effects of dislocation, persistant dislocation and reduction at varying intervals (immediately, 12, 24 and 48 hours after dislocation) of the left hip were studied by microangiographic, histological and radiographic examination. Dislocation of the left hip was induced manually under anaesthesia by a doraally applied force with the hip held adducted and internally rotated. Reduction was effected by ventral traction with the hip in the same position. The right hip was untouched and used as a control in all cases. In 135 animals, a tracer dye was infused into the abdominal aorta proximal to its bifurcation under standard conditions of temperature and pressure. This infusion was done at 10 minutes, and at 1, 3, 5, and 7 days after dislocation or reduction. The femoral heads were then processed and studied under stereomicroscopy. Histological and radiographic studies were made in the remaining 85 animals at intervals between 3 and 10 weeks after dislocation or reduction. In immature animals, severe dye perfusion defecit was observed in all cases within 10 minutes of dislocation. This was maximal in the antero-medial half of the femoral head. The defecit was increased at 24 hours and persisted until 5 days after dislocation. At the seventh day recovery had commenced. A profound perfusion defecit was also noted within 10 minutes of immediate reduction, however, recovery was observed at 24 hours and was almost complete at 5 - 7 days. The rate of recovery in those animals in which the dislocation was reduced at 12, 24 and 48 hours did not differ from that observed in unreduced animals. In adult animals, significant circulatory disturbance was infrequently observed after dislocation and persistant dislocation. Consequently, the beneficial effects of reduction, if any, were obscured. The epiphyseo-metaphyseal vascular anastomoses across the epiphyseo scar were filled with dye in all mature rabbits and seemed to act as a route of blood supply and drainage in adult animals.. Extensive histological avascular necrosis of the femoral head was observed in the majority of animals, but was significantly more common in immature rabbits. Less extensive and less common avascular necrosis was observed in immature animals after immediate reduction. However, reduction delayed to 12 hours or later was not associated with a lower incidence of bone death. Abnormal radiological findings were common and varied. Specific alteration in density and outline of the femoral head was however infrequently observed, but corelated well with the histological findings. Decreased biodensity was associated with inbalanced bone resorption and hyperaemia, and increased radiodensity with bone death and new bone apposition. It is concluded that traumatic dislocation causes embarassment and sequential changes in the circulation within the femoral head in rabbits. The perfusion defecit is more severe in immature animals as the intra-osseous epiphyseo-metaphyseal vessels minimize this circulatory disturbance in adult animals. Early reduction enhances early and complete recovery of blood supply in immature animals. Varying degrees of avascular necrosis of the femoral head occur in both adult and immature animals with and without reduction, but is more common and extensive in immature animals. Abnormal radiological features within the femoral head are infrequently observed up to ten weeks after dislocation but correlate well with the histological findings when present. / Surgery, Department of / Medicine, Faculty of / Graduate

Bilateral defects made in the lateral subtrochanteric area of the proximal femur in 16 dogs received Biocompatible Osteoconductive Polymer (BOP) fiber (n = 16), autogenous cancellous bone from the proximal femur (n = 4) or proximal humerus (n = 7), or no treatment (n = 5). BOP block was attached extraperiosteally to the proximal humerus in 7 dogs. Surgery sites were evaluated radiographically at 4 week intervals, and histologically 4, 8, 16, and 24 weeks postoperatively. Radiographic signs of bone healing were not observed in defects receiving BOP fiber. Control defects had radiographic signs of progressive bone ingrowth. Histologic evidence of bone formation was observed extending to but not incorporating BOP fibers. No connective tissue or bone ingrowth into BOP blocks was observed. Control defects healed by ingrowth of cancellous bone during the first 12 weeks following surgery and reformation of the lateral cortical wall by week 24. Cancellous grafted defects healed more rapidly and more completely than untreated defects. Although the mean weight of cancellous bone harvested from the proximal femur (0.82 ± 0.22g) was Significantly less (p < 0.05) than that harvested from the proximal humerus (1.38 ± 0.29 g), there was no qualitative difference in bony healing of grafted defects based on histologic and radiographic assessment. The results of this study indicate that BOP is not osteoconductive when used in subtrochanteric femoral defects or when placed extraperiosteally on the proximal humerus of normal dogs. This study also shows that the proximal femur can be safely used to provide moderate amounts of cancellous bone, with reharvesting from the same subtrochanteric donor Site possible after 12 weeks. / Master of Science

Thesis (MMed (Orth))--Stellenbosch University, 2014. / No abstract available

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references. Available also from UMI Company.

Knowledge of anatomy is an elementary step towards the understanding of the human body. First used by Alphonse Bertillon as an identification system, anthropometry refers to the measurements of human individuals. In orthopaedics, comparative analysis is widely used in the understanding of morphological variance due to races, sex and pathological conditions. The characterization of bone and joint geometry has also been a foundation of modern surgical implant design. Traditional anthropometric studies rely on physical measurements by means of osteometric table. Recent advancements of 3-D imaging modalities and image processing techniques have empowered more fine-grained anthropometric characterization. The inspiration for the study is: - the understanding of anatomy originating from the clinical domain have shown to contribute to undesirable inconsistency in the image processing domain. - the difficulty of existing automated anthropometric methodology in handling pathological femur. - the tedious amount of manual and subjective work involved with the increasing amount of high resolution imaging data. The aim of the study is to: - develop a consistent and robust methodology in accurate extraction of anthropometric parameters on the femur. - increase the level of automation on the process of anthropometric parameter extraction. With the bridging of anthropometry and the image processing disciplines, a robust methodology of anthropometric parameter extraction with high level of automation was developed, implemented and tested. A dataset comprised of femoral CT scans of 19 healthy Australian, 10 healthy Japanese, 15 Japanese diagnosed with primary or secondary hip osteoarthritis and 20 adult sheep was utilized for testing. Intra-class correlation and Cronbach's α were extensively employed to evaluate the intra-rater, interrater and repeated scans consistency of the proposed methodology. High correlation values (mean > 0.95) were noted suggesting a high consistency of the methodology. All healthy and osteoarthritis human datasets were processed successfully. With the structural similarity between the sheep and human femur, the robustness was further demonstrated by accurate processing of the sheep dataset without the need of any modification of the underlying methodology. The methodology proposed is highly automated and requires very few user interactions in the parameter extraction stage.