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To design and test hip joint prosthesis it is essential to know the magnitude and character of forces that may be applied to them in-vivo. For this thesis the hip joint forces of 40 to 60 year old subjects (five male and six female normal subjects and five male hip replacement) were studied. To allow the calculation of hip joint forces data from three-dimensional motion analysis and force plates were applied to a model of the lower limb. The model included the hip, knee and talocrural joints with 3 hip, 8 knee and 8 ankle joint forces, 4 knee ligaments and 47 muscle elements. A double linear optimisation technique (first minimising the maximum muscle stress then minimising the sum of the forces in the force bearing structures) was applied to solve the redundancy problem of force distribution in the muscles. Walking and stair, ramp and camber negotiation were characterised. Ground reaction forces, joint angles, intersegmental forces and moments, joint and ligament forces and muscle forces are presented. Muscle forces predictions were in general agreement with those in the literature, although the model was not capable of correctly distributing forces in the vasti or in the ankle only muscles as patella and talocalcaneonavicular joint equilibria were not included. In general, hip replacement subjects demonstrated lower hip joint forces than normal subjects. The range of maximum resultant hip joint forces for all activities was 3.04 to 11.85 for male normal subjects, 4.18 to 11.50 for female normal subjects, 3.73 to 6.81 and 2.21 to 8.77 for male hip replacement subjects for their natural and replaced sides respectively. The results presented define in three dimensions the hip joint forces in both pelvic and femoral axes systems and thus characterise the probable in-vivo requirements of hip joint prostheses during performance of the activities studied.

Wear is the number one concern with regards to the longevity of THR (total hip replacement). Therefore, reliable in-vitro prediction of wear is necessary. Thus, the laboratory should first validate their hip simulators with known clinical materials. The limiting factor in hip wear simulation has been the joint fluid analog. Using 100% bovine serum as the joint fluid analog, UHMWPE (ultra-high molecular weight polyethylene) wear-rates have been continually underestimated and PTFE (polytetrafluoroethylene) wear has been overestimated. Therefore, this work investigated the effect of protein concentration in bovine serum on the wear of PTFE and UHMWPE in a biaxial hip joint simulator. Validation criteria were developed based on the clinical findings of: ball size effect of increased wear with increased head size, 6% increase in wear for each millimeter of increased head diameter, clinical wear magnitudes, PTFE/UHWMPE wear-rate ratio and debris morphology. Both materials duplicated the clinical criteria using bovine serum with 10mg/ml of protein concentration. As protein concentration went from 0 to 10mg/ml, wear of both materials increased, however with greater than 10mg/ml protein; a) the rate of increase for PTFE was reduced by 80% and b) the wear of UHMWPE reversed, thus, showing that proteins cause wear. Additionally as the volume of fluid was increased, wear increased. This change in wear with protein concentration and volume was due to a protection of protein precipitate. As protein concentration increased protein precipitation increased and wear was decreased due to a protective layer of precipitates. Furthermore, wear protection was dependent on the amount of protein precipitation which was in turn, dependent on the initial concentration, volume of fluid and time. Therefore, wear in-vitro was dependent on the joint fluid analog. This work proved that the laboratory could duplicate clinical findings using bovine serum with 10mg/ml of protein concentration as the joint fluid analog and thus increase confidence in wear evaluation; taking the first steps to showing reliability of in-vitro THR wear studies.

Metal-on-metal hip resurfacing arthroplasty (MoMHRA) is an alternative treatment option to total hip arthroplasty (THA), especially in the young and active. Despite the early successful results, reports of adverse soft-tissue reactions around the MoMHRA have caused increased concern. These reactions have been termed pseudotumours and have been shown to be associated with increased wear. However, their incidence and aetiology is not known. The broad aims of this thesis were to 1) determine the clinical impact of pseudotumour; and 2) identify ways of reducing the risk of pseudotumour. The clinical impact was determined by examining the incidence and prevalence of pseudotumours needing revision and the subsequent outcome following revision. At the Nuffield Orthopaedic Centre, the 10-year survival of the BHR, commonest MoMHRA used, was 87.1% (95%CI: 83.0% to 91.2%) and the 10-year incidence of revisions due to pseudotumour was 7.5% (95%CI: 4.3% to 10.7%). In a prevalence study of two tertiary referral centres, pseudotumour was identified as the most common revision indication. An outcome based, case-control study characterised outcome following revision due to pseudotumour as inferior to that following revision for any other failure mode, and inferior to the outcome of matched primary THAs. The inferior outcome was associated with the extensive tissue damage at revision. Risk factors contributing to development of pseudotumour were found to be both patient and surgeon related. Patient factors significantly increasing risk included female gender and small component size. Case control studies demonstrated two surgical factors that were associated with significantly increased risk; cup malorientation and a reduction in head neck ratio (HNR) at operation particularly in females. Furthermore, evidence based recommendations were provided on optimum cup orientation and screening practice. Surgeons should aim for a radiographic cup inclination/anteversion zone of 45°/20° ± 10°. Patients with mal-positioned cups, those with high HNR prior to surgery, and those that had significant HNR reduction with the MoMHRA should be considered at increased risk of developing a pseudotumour. An ex vivo study demonstrated that the majority of pseudotumours occur due to high prosthesis wear, and result from an exaggerated innate response with an accompanying variable immune response. However a small but significant number of pseudotumours (20%) were observed with low wear and a prominent immune response. Furthermore, the cups oriented within the optimum zone were associated with less wear. Hence, subsequent in vivo research focused on providing evidence-based guidance on how to achieve the target cup orientation and factors to consider in minimising the scatter in cup orientation observed following hip arthroplasty. This great scatter was mostly due to two factors: 1) the variability between surgeons at orientating a component at implantation and 2) the difference in the pelvic position between implantation and radiographic assessment. The angular offset was 5° for inclination and 8° for anteversion because of the different definitions at impaction and X-Ray. Surgeons should need to be aware of these factors. Greater amount of pelvic movement occurs during MoMHRA, in comparison to THA. To achieve the target MoMHRA cup orientation surgeons should implant the cup with an intra-operative inclination/anteversion of 40°/30°. It is concluded that pseudotumour following MoMHRA has a significant clinical impact. In order to minimise it, surgeons should appropriately select patients and optimise surgical technique to achieve optimum cup orientation and try to avoid reducing the native head neck ratio. Appreciation of risk factors for pseudotumour development (female gender, small size component, cup orientation, HNR reduction), would aid detection prior to extensive soft-tissue damage and improve inferior outcome associated with revision.

A longitudinal content analysis of top-chart hip-hop songs’ lyrics produced between 1980 and 2013 was conducted to investigate the degree and progression of the paradoxical juxtaposition, or postmodern hybridity, of oppositional modernist identities in terms of race/ethnicity, gender, sexual orientation, sexuality, and economic lifestyle, in addition to the longitudinal diversification of artist’s race and gender demographics. Demographically, the percentage of non-African-American artists increased as the percentage of African-American artists decreased. Additionally, the percentage of songs featuring either all male or all female artists decreased, while the percentage of collaboration between male and female artists increased over time. Although hybrid oppositional identities related to race/ethnicity and gender did not increase over time, those of sexual orientation, sexuality, and economic lifestyle increased over time. In addition, materialist identities were related to the hybridity of sexual orientation and sexuality, but not to that of gender and race/ethnicity. Overall, the research found increasing postmodern hybridity within the sexualization of hip-hop songs along with intensified materialism.

A dissertation presented in partial compliance with the requirements for the Master's Degree in Technology: Chiropractic, Durban Institute of Technology, 2005. / The paucity of clinical research into the cause of canine hip dysplasia, efficacy and effects of the different treatment protocols available for the management of symptoms, as well as the differing presentations, has led to a continued variation in standardized care for this condition. The aim of this study was to contribute further information on the use of instrument manipulation as an alternative or adjunctive means of managing the symptoms of canine hip dysplasia. Both manual and instrument manipulation have effectively been used in the short-term management of human musculoskeletal pconditions, it was hypothesized that the use of instrument manipulation would benefit the canine patient. The use of human based studies was a guideline, as no previous chiropractic studies have been conducted on the canine subject. / M

Background: Hip fractures are among the most common causes of disability and hospitalisation in the elderly. Currently there are no studies available in South Africa that determine the factors that influence the early post-operative functional outcome in elderly patients with a hip fracture.Aim: To establish the factors influencing the early post-operative functional outcome in elderly patients with a hip fracture. Methodology: A prospective pre-test post-test observational study design was used. Consecutive sampling was used to recruit participants (n=72). Assessments were conducted pre-operatively, at discharge and six weeks post discharge at two public health care hospitals in Johannesburg, South Africa. Pre-operatively the pre-fracture functional mobility of the participants was determined using the New Mobility Score (NMS), the presence of pre-existing co-morbidities was assessed using the Cumulative Illness Rating Scale for Geriatrics (CIRS-G) and the cognitive function was assessed using the Six-Item Cognitive Impairment Test (6CIT). At discharge and at six weeks post discharge the participants post-operative functional level was assessed using the Elderly Mobility Scale (EMS) and the Lower Extremity Functional Scale (LEFS). A multiple regression analysis was used to determine associations. The study was set at p = 0.05 level of significance and 95% confidence interval (CI). Results: Participants were generally independent with pre-fracture mobility at baseline and presented with approximately three pre-existing co-morbidities. The presence of cognitive impairments in the participants decreased during the duration of the study, while the post-operative functional level in this population improved. Pre-fracture functional level was strongly related to and also the strongest predictor of post-operative functional outcome. The presence of co-morbidities and impaired cognitive function were also indirectly related. Conclusion: Pre-fracture functional mobility was found to be the strongest determinant of post-operative functional outcome, followed by cognitive function and the presence of pre-existing co-morbidities. By ensuring that these factors are optimal prior to sustaining a hip fracture, elderly patients are more likely to have better outcomes. For those patients who do sustain a hip fracture, intensive rehabilitation is especially necessary for the patient who presents with poor pre-fracture mobility, impaired cognition and pre-existing medical co-morbidities.

El objeto estudio de esta tesis doctoral se basó en investigar cualitativamente como los breakers (hiphoperos guayacos), redefinen sus prácticas culturales (los significados, valores, subjetividades como anhelos, aspiraciones) en la sociedad actual. Teniendo en cuenta que el arte urbano es un arte eminentemente social, que va en aumento en la ciudad de Guayaquil. Desde esta perspectiva es un fenómeno importante de estudio, en la vida social, no sólo por la diversidad de sus expresiones, sino por los múltiples procesos de significación que se articulan alrededor de su práctica, como los roles que asumen los jóvenes que lo practican, el papel que cumple el Hip Hop como expresión cultural en una sociedad diversa. La forma como construyen valores los jóvenes, sus relaciones con el entorno, con el mundo, sus aspiraciones, la construcción de su imaginación y procesos creativos en su práctica diaria y cotidianeidad. Esta tesis tomó como referencias teóricas los pensamientos de algunos autores, siendo uno de los más importantes: Merton con la Teoría de los grupos de Referencia, Schütz, Bauman, Lipovetsky, para fundamentar el objeto de estudio, e indagar a profundidad aspectos internos de vivencia de los jóvenes que practican hip hop danza desde su cotidianidad. La metodología que se utilizó tuvo un enfoque cualitativo, lo que permitió tener una perspectiva holística del fenómeno en estudio, centrada en el significado de las interacciones de las prácticas culturales de artistas hiphoperos,. La recolección de datos fue también de carácter documental- bibliográfico y de campo, lo que permitió describir, observar, descubrir y relatar el fenómeno en estudio. Los instrumentos utilizados para la recolección de la información fueron: la observación directa y observación participante, las entrevistas a profundidad e historias de vida de jóvenes hihoperos. PALABRAS CLAVES: Prácticas culturales, Hip Hop, artistas urbanos, sociedad actual. / --- The study object of this thesis is based on qualitative research as breakers (lignum vitae hiphoperos) redefine their cultural practices (the meanings, values, subjectivities and desires, aspirations) in today's society. Given that urban art is an eminently social art, which is increasing in the city of Guayaquil. From this perspective it is an important phenomenon of study, in social life, not only for the diversity of its expressions, but by the multiple processes of meaning that articulate about their practice, the roles assumed by the young people who practice it, the role of the Hip Hop as a cultural expression in a diverse society. How young people build values, relationships with the environment, with the world, aspirations, building your imagination and creative processes in their daily practice and daily life. This thesis took as theoretical references the thoughts of some authors, one of the most important it was: theory of reference groups: Merton, Schütz, Bauman, Lipovetsky, to support the object of study, and inquire in depth experience of internal aspects youth hip hop dance practice from their daily lives. The methodology used was a qualitative approach, which allowed having a holistic view of the phenomenon under study, focused on the meaning of the interactions of the cultural practices of hip-hop artists. Data collection was also documentary- character bibliographic and field, allowing describe, observe, discover and report the phenomenon under study. The instruments used for data collection were: direct observation and participant observation, in-depth interviews and life stories of young hiphoperos. KEYWORDS: Cultural practices, Hip Hop, urban artists, actual society / Tesis

The lack of hamstring muscle group flexibility has previously been associated with a higher incidence of hamstring strains among athletes. Several stretching methods have been shown to increase hip joint range of motion (ROM); however, identification of an optimal stretching method has proven difficult. The purpose of this study was to find an optimal method of stretching to improve hip flexion range of motion. Forty-three female college students, ranging in age from 18 to 29 yrs., volunteered to participate in this study. The subjects were randomly assigned to one of three stretching groups: static, contract relax, contract relax agonist contract. The subjects' maximal passive and active hip flexion ROM values were measured using an inclinometer. The subjects were stretched by the same partners at a rate of six days a week for a total of 20 treatments over a 23 day period. The selected stretching techniques produced significant pretest to posttest increases (p<0.02) in both passive and active hip flexion ROM. None of the stretching techniques improved passive or active hip flexion ROM significantly more the contract relax agonist contract technique producing an average increase of 17.6 �� 14.1 deg, and the contract relax technique resulting in an average increase of 12.0 �� 10.8 deg. A significant stretching technique x pretestiposttest interaction was found for the passive ROM values (p<.02). Scheffe' post hoc analysis of simple interaction effects revealed that the static stretching technique improved posttest passive hip flexion ROM significantly more than the PNF contract relax stretching method (p<.05). The results suggest that all three stretching techniques selected for this study are effective in increasing hip flexion range of motion. Static stretching of the hamstring produced the greatest increases in both passive and active hip flexion ROM, but no optimal technique was identified. / Graduation date: 1996

Acetabular labral tears are associated with hip osteoarthritis. A current surgical treatment strategy for a torn labrum, labral resection, has recently shown poor patient outcomes with radiographic signs of osteoarthritis two-years post-operation. Since mechanical factors play a role in the etiology of osteoarthritis, identifying the mechanical role of the labrum may enhance current surgical treatment strategies. In this pilot study, we assessed the relationship between mean cartilage strain, maximum cartilage strain and the three-dimensional cartilage strain distribution in six human cadaver hips with various pathologic conditions of the labrum. We developed a novel technique of mapping cartilage strain using quantitative magnetic resonance imaging (qMRl). qMRl provides a non-invasive means of quantifying the cartilage strain distribution in the hip in three dimensions. Each specimen was assessed first with an intact labrum, then after surgically simulating a longitudinal peripheral labral tear, then after arthroscopically repairing the tear, and after labral resection. We validated the precision of the technique through use of an additional specimen which served as a control. To minimize motion artifact in the high-resolution MR images, we determined that 225 minutes was required for cartilage to reach a steady-state thickness under load. We also determined 16.5 hours was required for cartilage to recover to a steady-state unloaded thickness. The difference in mean and maximum cartilage strain when the labrum was repaired and resected was assessed using a paired t-test. We found that the resected group had an increased mean and maximum cartilage strain of 4% and 6%, respectively and the 3D cartilage strain distribution was elevated throughout the region of interest. When the condition of the intact labrum was compared to the torn labrum, we found no change in mean and maximum cartilage strain, and little obvious change in the 3D pattern of cartilage strain distribution. Based on our findings of increased cartilage strain after labral resection when compared to labral repair, we hypothesize that the labrum’s contribution of additional surface area assists in load distribution, which spares cartilage from excessive loads. We therefore recommend that the longitudinal peripheral torn labrum should not be resected if it is possible to be repaired, because in vivo, labral resection may create an environment with increased articular cartilage strain, which is thought to be associated with cartilage degeneration.