Habilitation-Thesis--Cologne. / Includes bibliographical references (p. 45-48) and index.

Thesis (M.S.)--University of Toledo, 2005. / Includes bibliographical references (leaves 44-46). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

Thesis (M.S.)--University of Toledo, 2005. / Includes bibliographical references (leaves 44-46).

Made available in DSpace on 2014-06-11T19:23:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-10-06Bitstream added on 2014-06-13T19:50:51Z : No. of bitstreams: 1 barros_lp_me_jabo.pdf: 894125 bytes, checksum: 291c2da790713462f8653ad7c1ce412f (MD5) / No presente trabalho comparou-se, experimentalmente, duas técnicas: a estabilização coxofemoral com pino em cavilha ou “toggle pin” e a colocefalectomia. Foram utilizados 16 cães, machos ou fêmeas, distribuidos em dois grupos: o de Pino (GP) e o Colocefalectomia (GC), os quais foram separados em 4 subgrupos: animais com peso superior e, inferior ou igual a 15 kg. Avaliou-se o tempo de cirurgia, o grau de atrofia muscular, a deambulação e a dor, além de presença ou não de alterações radiograficas da articulação. O tempo cirúrgico, devido a maior complexidade da técnica do pino, foi menor no GC. A técnica do GP foi melhor quanto à recuperação do membro, apresentando menor atrofia muscular / On the present assay was compared experimentally between two techniques: hip joint stabilization with toggle pin and hip joint stabilization with head of the femur. Were used 16 dogs, female or male, distributed in 2 groups: the pin group (GP) and head of the femur group (GC), the groups were distributed in 4 subgroups: by weight equal, more or less than 15kg. Evaluating the time of surgery, and the notch of muscle atrophy, wander around the pain and also with the presence or not of alterations on the joint radiograph. The time of surgery is longer in the technique of pin than on the group GC, because the technique of pin had more complexity. So the technical of the group GP was better on the recovery member, which presented less muscle atrophy

Synovial joints, like the hip joint, has unique characteristics. In order to study these characteristics by making use of mathematical techniques, it is necessary to develop a model simulating the dynamic forces and joint movements during joint operation. Once this is available, the effect of the synovial fluid lubricant properties can be added by describing its behaviour as a component of the hip joint simulation model. This was the ultimate aim of this research effort. With this work a model based on fundamental principles, like the equations of mass and motion, was developed and validated experimentally with a hip joint simulator. It is also shown that the effect of the lubricant properties can be studied by adding the relevant rheological equations. These fluid properties can have a significant effect on the joint under typical joint operations like dynamic loading and movement. To develop a model with relative complexity, certain simplifying assumptions have to be made. In this study, the fluid was assumed to have no boundary interactions with the articulating surfaces. It is known that complex rheological interaction exists in these systems. Although certain assumptions were made during development, model results are promising and a firm basis was established for subsequent research. In future, the model needs to be extended to simulate the continuous, multi-cycle operation of a human joint, with accurate geometrical descriptions of articulating surfaces and known components of synovial joints like articular cartilage. The model could then contain lubrication mechanisms known to prevail in synovial joints, with accurate rheological models of synovial fluid which will play an increasing role under typical joint operations. / Dissertation (MEng (Chemical Engineering))--University of Pretoria, 2007. / Chemical Engineering / unrestricted

No description available.

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

Femoro-Acetabular Impingement (FAI) is a hip joint disease which affects and impairs the range of hip motion during performing activities of daily living, jogging, walking, or climbing stairs due to the bony abnormalities of the joint. Ballet dancers and athletes (e.g. gymnasts and hockey players) put their hips at the risk of FAI by extremely moving the hip mainly by excessively rotating the joint. In this research, we introduce a visualization system which helps surgeons to analyze the range of hip motions as well as to have a better communication with patients. These goals are achieved by presenting three dimensional (3D) visualizations of motion envelope by examining the maximum possible rotation of the digital hip bones. Our computer simulation system estimates, analyzes and visualizes the maximum hip range of motion (ROM) for the constructed 3D bone models that are extracted from Magnetic Resonance Images (MRI) after segmenting the bones. These tasks are accomplished by first calculating Hip Joint Center (HJC) which is center of rotation of femoral head on the 3D segmented MRI models followed by simulating hip motions with examining impingement between the femur and the acetabulum using our collision detection system. In our collision detection system, surfaces of femoral head and acetabulum bones are sampled in the spherical coordinates based on rasterization and interpolation. Then, the distance between the femoral head and acetabulum are computed to prevent impingement between them. The maximum motion degree of femur bone within depression of acetabulum in every direction during the digital simulation shows the ROMs of the inputted MRI of the hip joint. Six primary plane motions (flexion/extension, abduction/adduction and internal/external rotation) as well as various combinations of these motions (maximum rotation of the hip between every two rotational movements) and successive movements (maximum rotational movement of the hip per another rotational movement) are simulated and analyzed along with 3D visualization of estimated range of these motions. Generally, the ROM differs by some factors such as age, gender, ethnicity, and geographic location. For instance, newborns up to age two have considerably greater motion in hip flexion and hip abduction than adults. Our system by 3D visualization of motion envelope will provide a platform to understand quicker and better the effect of bony morphology of the hip joint on the possible ROM. We also examine the long-standing question about moving center of rotation related to ROM. We found out the ROM becomes bigger especially when the center moves outward to the direction of acetabulum axis. This thesis does not consider the effect of muscle and other surrounding connective tissue on the hip ROM since they can be altered significantly by physical training to show the potential of maximum ROM. For example a ballerina has a bigger ROM leading a bigger motion envelope compared with non-dancers. Hence we visualize the range of joint motions and their envelopes that are obtained from the osseous anatomy of the hip joint. The osseous anatomy of the joint is the most fundamental and permanent factor of ROM which indicates the maximum motion that the joint can achieve if the muscle and other connective tissues are perfectly trained.

No description available.

No description available.