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1
Berg, Svante. "On Total Disc Replacement." Doctoral thesis, Linköpings universitet, Ortopedi och idrottsmedicin, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-54290.
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Low back pain consumes a large part of the community’s resources dedicated to health care and sick leave. Back disorders also negatively affect the individual leading to pain suffering, decreased quality-of-life and disability. Chronic low back pain (CLBP) due to degenerative disc disease (DDD) is today often treated with fusion when conservative treatment has failed and symptoms are severe. This treatment is as successful as arthroplasty is for hip arthritis in restoring the patient’s quality of life and reducing disability. Even so, there are some problems with this treatment, one of these being recurrent CLBP from an adjacent segment (ASD) after primarily successful surgery. This has led to the development of alternative surgical treatments and devices that maintain or restore mobility, in order to reduce the risk for ASD. Of these new devices, the most frequently used are the disc prostheses used in Total Disc Replacement (TDR). This thesis is based on four studies comparing total disc replacement with posterior fusion. The studies are all based on a material of 152 patients with DDD in one or two segments, aged 20-55 years that were randomly treated with either posterior fusion or TDR. The first study concerned clinical outcome and complications. Follow-up was 100% at both one and two years. It revealed that both treatment groups had a clear benefit from treatment and that patients with TDR were better in almost all outcome scores at one-year follow-up. Fusion patients continued to improve during the second year. At two-year follow-up there was a remaining difference in favour of TDR for back pain. 73% in the TDR group and 63% in the fusion group were much better or totally pain-free (n.s.), while twice as many patients in the TDR group were totally pain free (30%) compared to the fusion group (15%). Time of surgery and total time in hospital were shorter in the TDR group. There was no difference in complications and reoperations, except that seventeen of the patients in the fusion group were re-operated for removal of their implants. The second study concerned sex life and sexual function. TDR is performed via an anterior approach, an approach that has been used for a long time for various procedures on the lumbar spine. A frequent complication reported in males when this approach is used is persistent retrograde ejaculation. The TDR group in this material was operated via an extra-peritoneal approach to the retroperitoneal space, and there were no cases of persistent retrograde ejaculation. There was a surprisingly high frequency of men in the fusion group reporting deterioration in ability to have an orgasm postoperatively. Preoperative sex life was severely hampered in the majority of patients in the entire material, but sex life underwent a marked improvement in both treatment groups by the two-year follow-up that correlated with reduction in back pain. The third study was on mobility in the lumbar spinal segments, where X-rays were taken in full extension and flexion prior to surgery and at two-year follow-up. Analysis of the films showed that 78% of the patients in the fusion group reached the surgical goal (non-mobility) and that 89% of the TDR patients maintained mobility. Preoperative disc height was lower than in a normative database in both groups, and remained lower in the fusion group, while it became higher in the TDR group. Mobility in the operated segment increased in the TDR group postoperatively. Mobility at the rest of the lumbar spine increased in both treatment groups. Mobility in adjacent segments was within the norm postoperatively, but slightly larger in the fusion group. In the fourth study the health economics of TDR vs Fusion was analysed. The hospital costs for the procedure were higher for patients in the fusion group compared to the TDR group, and the TDR patients were on sick-leave two months less. In all, these studies showed that the results in the TDR group were as good as in the fusion group. Patients are more likely to be totally pain-free when treated with TDR compared to fusion. Treatment with this new procedure seems justified in selected patients at least in the short-term perspective. Long-term follow-up is underway and results will be published in due course.
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Schrader, Kate. "Knee Surgery: Total Knee Replacement or Partial Knee Replacement." University of Toledo Honors Theses / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=uthonors1305216135.
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Ajemian, Stanley V. "Gait changes following total hip replacement." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq24641.pdf.
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Smyth, Alexandra. "Wear of a total ankle replacement." Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/19367/.
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Ankle arthritis affects 1% of the population and can be a painful debilitating problem. One motion preserving treatment option is total ankle replacement (TAR). These devices are currently under researched and have poor clinical outcomes. Despite significant variation amongst device designs no pre-clinical test standards exist to allow comparison of tribological function. Furthermore, malalignment of TARs is a potential result of surgical technique or failure to correct existing natural varus/valgus deformity. TAR malalignment can result in instability, deformity and is associated with increased wear and higher failure rates. Good alignment is considered instrumental for long term success. The aim of this research was to develop clinically relevant wear test methodologies for both natural gait and adverse conditions. First a parameterised test was undertaken to understand the critical parameters for the Zentih (Corin Group) TAR. A knee simulator was used to vary the combination of rotation and displacement and the change in wear rate was assessed gravimetrically. The effects of malalignment were investigated biomechanically in terms of component lift-off, changing contact area and stress. Adverse conditions were defined based on these results and edge loading observed in retrieved TARs. One coronal malalignment condition and a 3mm translational offset were tested in the wear simulator previously developed. Rotation proved to significantly increase the TAR wear rate while displacement had no significant effect. Implementing coronal malalignment alone resulted in a significant decrease in the wear rate, due to the reduced contact area while edge loading had no significant effect. This outcome may not translate to reduced wear in a complex biological environment, however simulation methods produced clinically comparable surface form. This PhD highlighted the critical parameters for TAR wear simulation, however, TAR failure is bigger than wear alone. Further factors must be considered to develop a truly adverse pre-clinical test protocol.
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Gibson, Clare Naomi. "The effect of personality on recovery from total hip replacement and total knee replacement in patients with osteoarthritis." Thesis, University of Sheffield, 2007. http://etheses.whiterose.ac.uk/6097/.
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Background: Total hip replacement (THR) and total knee replacement (TKR) are increasingly common procedures to treat the pain and disability associated with osteoarthritis. There is a large variability in time to achieve functional milestones following these procedures and of success of surgery measured by pain and functional ability. Factors which affect outcome are poorly understood, but research in health psychology suggests psychological variables may play an important role. Objectives: To explore the relationships between selected psychological variables with pain and function pre-operatively in patients awaiting THR and TKR, on achievement of key functional milestones as an inpatient post-operatively, and of pain and function three-months post-operatively. Design: A correlational study of patients undergoing primary unilateral THR and TKR as a result of osteoarthritis. Subjects: 105 THR, 70 TKR. Psychological Measures: NEO-Five Factor Inventory, Multi-dimensional Health Locus of Control Questionnaire, Coping Strategies Questionnaire. Outcome Measures: Oxford Hip Score, Harris Hip Score, Oxford Knee Score, Knee Society Knee Score, key functional physiotherapy milestones. Results: Hip Study: Catastrophizing was a significant predictor of greater pain and worse function both pre-and post-operatively. Pain control efficacy was predictive of less pain and better function pre- and post-operatively. In addition, conscientiousness was a predictor of worse pre-operative function. Few psychological variables were predictive of physiotherapy outcome measures. Knee Study: Neuroticism was found to be a predictor of worse pain both pre- and post- operatively. Pre-operatively openness to experience was predictive of less pain and better function. Post-operatively, a chance locus of control was predictive of worse functioning. Few psychological variables were predictive of physiotherapy outcome measures. Conclusions: Psychological variables influence pain and function both pre- and post- operatively in THR and TKR. The psychological variables may exert their actions through pain control efficacy. There is scope to develop an intervention targeting negative psychological variables and improve outcome.
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Walter, William Lindsay School of Biomechanics UNSW. "Severe biomechanical conditions in total hip replacement." Awarded by:University of New South Wales. School of Biomechanics, 2006. http://handle.unsw.edu.au/1959.4/25968.
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Hip simulators are designed to reproduce the forces and motion patterns of normal walking. In vivo demands on total hip replacements, however, are varied and often more severe than normal walking conditions. It is these severe conditions that often lead to implant failure. This is clinically based research aimed at understanding some of the more severe conditions in hips and the effect that these have on the performance of the total hip replacement. The polyethylene liner can act as a pump in an acetabular component, forcing fluid and wear particles through the holes to the retroacetabular bone causing osteolysis. Ten patients were studied at revision surgery. Pressures were measured in retroacetabular osteolytic lesions while performing pumping manouvers with the hip. Two laboratory experiments were then designed to study pumping mechanisms in vitro. In patients with contained osteolytic lesions, fluid pressure fluctuations could be measured in the lesion in association with the pumping action. Patients with uncontained osteolytic lesions showed no such pressure fluctuations. In the laboratory we identified 3 distinct mechanisms whereby fluid can be pumped from the hip joint to the retroacetabular bone. These pumping effects could be mitigated by improved implant design. Loading of the femoral head against the edge of the acetabular component produces dramatically increased contact pressures particularly in hard-on-hard bearings. In an analysis of 16 retrieved ceramic-on-ceramic bearings we were able to characterise the mechanism of edge loading based on the pattern of edge loading wear on the bearing surface. Finally in a radiographic study of patients with squeaking ceramic-on-ceramic hips. Squeaking was found to be associated with acetabular component malposition. It seems that edge loading or impingement may be an associated factor in these cases.
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ToyeÌ, Francine M. A. "Assessing the need for total knee replacement." Thesis, Coventry University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400792.
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Warwick, David John. "Deep vein thrombosis after total hip replacement." Thesis, University of Bristol, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283969.
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Torabi, Kachousangi Ehsanollah. "Edge loading effect on total hip replacement." Thesis, University of Warwick, 2016. http://wrap.warwick.ac.uk/90967/.
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The most important hip post-surgery problem is named Edge Loading (EL). This phenomenon significantly increases the contact pressure on the ball and the socket of the hip prosthesis hence decreasing the lifetime of the hip prosthesis drastically. Nowadays millions of patients cannot go under total hip replacement surgery due to the short lifetime of the hip prostheses. This research mainly focuses on finding solution for reducing the effect of this phenomenon. In this research, reasons of EL are investigated and important factors in designing of the prosthesis are studied. Furthermore, a novel hip prosthesis is proposed. The model has been successfully patented with PCT number: PCT/GB2015/052933 and published with International Publication Number: “WO2016/055783Al”. In this study the proposed design is analysed using three methods and the results are compared with the best available hip prosthesis in the market. The key results of the proposed design are outlined below: -Comparison of the features of the proposed design with those of the available hip prosthesis suggests a promising outcome. This is mostly due to eliminating of the EL causes, in the new design. -According to Hertzian Contact Theory, the proposed design reduces contact pressure during EL by 99.7% in comparison with the best available prosthesis in the market. This represents an upper limit. -Finite element method simulation demonstrates up to 63% reduction (lower limit) of contact pressure during EL and also Neck-Rim/Ring impingement by the proposed design in comparison with the best available prosthesis in the market. Although reduction of contact pressure by the novel design is noticeable, aforementioned methods show different results. This is due to the limitation of every method in this study. In this regard the novel design expecting to reduce contact pressure during EL / Microseparation more than 63% but less than 99.7%. The novel design may open a new path for the total hip replacement surgery, and solve the EL problem forever.
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Elliott, Bradley Jay. "Optimization of WSU Total Ankle Replacement Systems." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1341333609.
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Pasko, Kinga Marta. "Ceramic coatings for cervical total disc replacement." Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/19486/.
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Surgical interventions for the treatment of chronic neck pain, which affects 330 million people globally, include fusion and cervical total disc replacement (CTDR). Most of the currently clinically available CTDRs designs include a metal-on-polymer (MoP) bearing. Numerous studies suggest that MoP CTDRs are associated with issues similar to those affecting other MoP joint replacement devices, including excessive wear and wear particle-related inflammation and osteolysis. The aim of this study was to investigate the biotribology of a novel metal-on-metal (MoM) design of cervical total disc replacement device in its pristine form and coated with chromium nitride or silicon nitride, in order to understand the influence of loading conditions upon the tribological performance of the implant, and to investigate biological effects of the wear debris produced by the implants. To achieve this, a series of studies were carried out. Chromium nitride and silicon nitride coatings have been characterised for their mechanical properties, chemical composition and surface finish. Whilst some of the experiments showed minor differences between the mechanical properties and adhesion of the coatings, there was no indication of significant differences between the chromium nitride and silicon nitride coated samples. Functional testing in the six-station spine wear simulator showed that MoM CTDRs produced wear volumes significantly lower than those of the commercially available MoP devices. The wear volumes were reduced further by three-fold, following testing under altered ISO-18192-1:2011 kinematics, whereby, reduced ranges of motions were applied. Whilst the silicon nitride coated CTDRs failed catastrophically early in the test, chromium nitride coated CTDRs produced an eight-fold reduction in wear volumes, when compared to the pristine devices tested under the same conditions. Investigation of potential biological effects of the particles generated in wear testing showed that that high concentrations (5-50µm3 per cell) of CoCrMo particles resulted in significant reduction of cell viability of the L929 fibroblast cells, but not the dural fibroblasts, which were used in this study. No ceramic coating particles, at any concentrations, caused significant reduction of cell viability. In summary, results presented in this thesis showed that whilst the MoM CTDR device exhibited significantly lower wear rates than those of the commercially available MoP devices, the cytotoxic wear particles could potentially lead to adverse biological reactions, particularly in patients with metal hypersensitivity, and lead to devastating consequences similar to those of failed MoM THRs. Currently, the consequences of similar failure, leading to metalosis or pseudotumour formation in the vicinity of the spinal cord are unknown. During the investigation of the ceramic coatings, it was also found that chromium nitride ceramic coating could not only lower wear rates further, but it also has the potential to reduce the cytotoxic potential of the wear particles.
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Poon, Mei-ying Dora. "Gait analysis of normal and total knee replacement subjects /." Hong Kong : University of Hong Kong, 1997. http://sunzi.lib.hku.hk/hkuto/record.jsp?B18539142.
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Timperley, Andrew John. "Early complications relating to the acetabular component after total hip replacement." Thesis, University of Oxford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670193.
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Malik, Khan Aamer. "Validation of computer navigation for total hip replacement." Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/384238.
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Introducción: Está demostrado que incluso los cirujanos de cadera con una elevada experiencia, mal-posicionan los implantes durante la artroplastia total de cadera, pudiendo colocar los implantes fuera de la zona segura en casi un 50% de los casos. Las consecuencias de la mal-posición de implantes serían el impingement, la luxación, el aflojamiento aséptico, el desgaste, la osteolisis y dolor, pudiendo producir unas consecuencias dramáticas en la calidad de vida y funcionalidad de los pacientes. Este tesis describe la validación de un sistema de navegación sin imágenes primero con un fantoma y también clínicamente, para la precisa colocación del implante acetabular y femoral durante la artroplastia total de cadera. La información obtenida mediante esta reconstrucción numérica cambio nuestra técnica tradicional de colocar primero el cótilo hacia un número diana, a preparar primero el fémur y después la cadera con una anteversion combinada adecuada a unos números diana, técnica que validamos al final del estudio.
Materiales y Métodos: Primero, validamos nuestro sistema de navegación mediante un fantoma que diseñamos. Comparamos los resultados de la posición acetabular real del fantoma con las lecturas del sistema de navegación y de las imágenes de Tomografía Computarizada (TC) procesadas del fantoma. Esta información fue procesada mediante dos sistemas computarizadas de reconstrucción 3D de cadera independientes (HipNav® and Orthosoft®). Una vez la fiabilidad del sistema fue verificado, realizamos estudios clínicos sobre diferentes cohortes de pacientes sometidos a artroplastia total de cadera no-cementada con navegación. Comparamos la precisión del cirujano para colocación de implantes a la del sistema de navegación. Estos resultados fueron validados mediante TC postoperatorio.
Resultados: El fantoma confirmó que el Sistema de Navegación sin imágenes Navitrack, tenía una precisión de 1° y un sesgo de 0.02° para la inclinación y una precisión de 1.3° con un sesgo de 0° para medidas de anteversion. Clínicamente, la precisión del sistema de navegación del acetábulo fue de 4.4° con un sesgo de 0.03° para la inclinación y 4.1° con un sesgo de 0.73° para la anteversion. La precisión de los cirujanos con mucha experiencia fue de 11.5° para la inclinación y 12.3° para la anteversion, mientras que los cirujanos con menos experiencia tenían una precisión de 13.1° para la inclinación y 13.9° para la anteversion del cótilo. Para la versión del implante femoral, al comparar los valores del navegador a los TC postoperatorios, su precisión era de 4.8° con un sesgo de 0.2°. Al comparar las estimas del cirujano al navegador, su precisión fue de 16.8° con un sesgo de 0.2°. Confirmamos que el navegador tiene una precisión con error de < 5° y sesgo de < 1° para la colocación de implantes y siempre fue superior a los cirujanos. La anteversion combinada medida mediante TC postoperatorio fue de 37.6° ± 7° (rango 19°–50°). La anteversion combinada con navegación estaba dentro del rango deseado de 25° a 50° en 96% de caderas.
Conclusiones: Demostramos que el cirujano solo mediante su experiencia y intuición no puede colocar los implantes de una prótesis de cadera en la posición deseada. La artroplastia de cadera mediante la navegación es clínicamente precisa para la colocación del implante femoral y acetabular con un error de menos de 5°. La versión final del implante femoral no-cementado es muchísimo más variable de lo que se pensaba. Usando una herramienta precisa, previamente validada, para obtener información numérica intraoperatoria, llevamos a cabo una novedosa técnica de anteversion combinada para la reconstrucción de la artroplastia de cadera. Estudios a largo plazo que validen el coste efectividad y supervivencia de implantes con esta tecnología determinaran el papel de la navegación en nuestras cirugías de cadera de día a día.INTRODUCTION Even vastly experienced high-volume hip surgeons have been shown to be inaccurate with implant positioning during total hip replacement. Surgeons position the acetabular implants inclination and version, and femoral implants version out of the safe zone in almost 50% of cases. Consequences of implant mal-position are impingement, dislocation, aseptic loosening, wear, osteolysis and pain. These have dramatic effects on the patients’ functional outcome and quality of life. This thesis outlines the validation of an imageless navigation system with a phantom model, and posteriorly clinically, for accurate acetabular and femoral implant positioning during total hip replacement. The information obtained with this numerical reconstruction shifted our traditional surgical technique of placing the acetabulum first towards target numbers, to a femur first combined anteversion technique, which is validated at the end of the study. MATERIALS AND METHODS First, we validated our navigation system with a phantom model which we designed. We compared the readings of the imageless navigation system, and processed Computer Tomography (CT) scanned images of the phantom, with the true values of the phantom models acetabulum. This data was processed using two independent computer based hip reconstruction systems (HipNav® and Orthosoft®). Once robustness of the system was confirmed, clinical studies were undertaken in different cohorts of patients undergoing non-cemented total hip replacement with computer navigation between 2004 and 2009. The surgeon’s accuracy for implant positioning was compared to that of the navigation system. These results were validated by postoperative CT-scans (gold standard for postoperative implant position validation). RESULTS The phantom model confirmed that the Navitack Imageless Computer Navigation System had a precision of 1° and a bias of 0.02° for inclination and a precision of 1.3° and a bias of 0° for anteversion measurements. Clinically, the accuracy of the navigation system for the acetabulum was a precision of 4.4° with a bias of 0.03° for inclination and 4.1° with a bias of 0.73° for anteversion. The experienced surgeons’ precision was 11.5° for inclination and 12.3° for anteversion, whereas the less experienced surgeons’ precision was 13.1° for inclination and 13.9° for anteversion. For the femur implants version, on comparing the navigation systems values to postoperative CT-scans, its precision was 4.8° and bias was 0.2°. On comparing surgeon’s estimates to navigation, their precision was 16.8° with a bias of 0.2°. The distribution of femoral stem version had a wide variability (far from the assumed 15°) from complete retroversion to high anteversion. We confirmed that computer navigation had a precision of less than 5 degrees and bias of less than 1 degree for hip implant positioning, and was always better than that of surgeons. Combined anteversion by postoperative computed tomography scan was 37.6° ± 7° (range, 19°–50°). The combined anteversion with computer navigation was within the safe zone of 25° to 50° in 45 of 47 (96%) hips. CONCLUSIONS We demonstrated that the surgeon, through experience and intuition alone, cannot place implants within the desired positions. Hip replacement using computer navigation is clinically accurate to within 5° for acetabular and femoral implant positioning. There is far greater variability in femoral version of non-cemented implants than previously estimated. Using an accurate validated tool for numerical intraoperative information, we undertook a novel hip reconstruction method described as the combined anteversion technique. We believe it will reduce the risk for impingement and its complications. Long-term studies that validate improved implant survival and cost effectiveness with this expensive technology will help determine its future role in our day-to-day hip surgery
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Crawford, Ross William. "Focal femoral osteolysis in cemented total hip replacement." Thesis, University of Oxford, 2000. http://ora.ox.ac.uk/objects/uuid:67914dbd-6405-41a3-b4d6-6baeb8bbf0bf.
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As implant survival extends into the second and third decades focal osteolysis around cemented femoral components in total hip replacement is emerging as an important failure mechanism. Whilst the problem of focal osteolysis is well recognised, there are many aspects of its development which are poorly understood. The broad aim of this thesis is to try to provide some insights into how, why and where focal osteolysis develops around the cemented femoral component. There are broadly two sections to this thesis, chapters 2-5 present clinical and geometrical studies and chapters 6-10 a series of experimental studies. The aim of the first section was to establish what is observed in clinical practice, the aim of the second to try to explain these findings. A mid-term clinical study showed that focal osteolysis is more common with rough than polished stems that differed in no aspect other than their surface finish. Further studies established that focal osteolysis is probably always associated with defects in the cement mantle. These defects occur anteriorly at the mid-stem of the prosthesis and posteriorly at the component tip. The distribution of focal osteolysis and its strong association with cement mantle defects suggests the importance of the stemcement interface as a pathway for fluid and debris to reach the distal femur. However, at 15-25 years, osteolysis rarely develops with the polished Exeter stem even in the presence of confirmed defects in the cement mantle, suggesting that the stem seals the stem-cement interface against fluid and debris. In an attempt to explain the clinical findings a series of bench top experiments were undertaken. These studies showed that the behaviour of fluid and dye at the stemcement interface was significantly influenced by component surface finish. Bonded and debonded stem-cement interfaces of rough stems provided an incomplete barrier to fluid movement along this interface. In contrast, polished stems both bonded and debonded were able to provide a seal at the stem-cement interface. The seal at this interface was improved with component subsidence in the presence of rotational stability. It is believed that this thesis provides a rationale explanation for why focal osteolysis rarely develops around the Exeter stem in clinical practice. It also explains how, where, and why osteolysis develops around certain designs of cemented femoral components used in total hip replacement.
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Cook, Juliette Emma. "Fretting wear of total hip replacement femoral stems." Thesis, University of Exeter, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263286.
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Loughenbury, Faye Alexandra. "Minimising leg length inequality after total hip replacement." Thesis, University of Leeds, 2018. http://etheses.whiterose.ac.uk/21329/.
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The total hip replacement is one of the most effective medical interventions undertaken, with high reported rates of pain relief and patient satisfaction 1,2. Leg length inequality (LLI) following total hip replacement was first recognised by Charnley when the operation was popularised but has only recently increased in prominence in the literature. The definition of an unacceptable value of LLI is controversial and is complicated not only by the lack of agreement of significance but also by the fact that for any given magnitude of LLI, only a proportion will be symptomatic. This thesis begins by exploring the opinions of British Hip Society (BHS) members to generate an expert opinion on acceptable values. Findings were in broad agreement with the literature, with 6784% of respondents stating they believed that LLI of less than 10mm would always be within the bounds of acceptable practice. A second survey of BHS members regarding methods of minimising LLI intra-operatively identified that 77% of surgeons use the Shuck technique during every total hip replacement, and that 11% use a commercial device. Chapter four evaluated five commonly used intra-operative tests and concluded that when used in combination these tests could produce acceptable values of LLI. Most reliance was placed on the Shuck technique during decision making. Results from this work identified scope for development of a novel device to be used as an adjunct to the Shuck test as an indirect measurement of leg length. A device was designed and manufactured and preliminary results from in vivo studies show a narrow range of both distraction distance and force applied during the Shuck test. These results indicate that the device could be developed further to standardise the Shuck test and use it as an adjunct to train junior surgeons how to assess leg length, minimising the requirement for subjective and invasive methods.
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Gul, Rizwan Mahmood 1967. "Improved UHMWPE for use in total joint replacement." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10226.
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Woolhead, Gillian Mary. "Patients' experience of osteoarthritis and total knee replacement." Thesis, University of Bristol, 2002. http://hdl.handle.net/1983/5fb81a12-786d-48ed-9cbe-9c2246d5ff5f.
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Soderholm, Kevin Jeffrey. "Drug Treatment Comparison for Total Knee Replacement Surgery." Thesis, North Dakota State University, 2015. https://hdl.handle.net/10365/27686.
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In this study, we aim to better understand how spinal block, anticoagulant, and antifibrinolytic drug treatments are associated with hospital costs, lengths of stay, prevalence of early readmissions, and prevalence of blood transfusions for total knee replacement patients. Analysis of variance, multiple comparison testing, ordinary least squares regression, and logistic regression were used to identify which combinations of these drug treatments were associated with higher or lower health outcomes. The combination of Lidocaine and Ropivacaine was the spinal block treatment associated with the highest mean hospital cost, length of stay, highest proportion of early readmissions, and required blood transfusions. The combination of Warfarin and Enoxaparin was the anticoagulant treatment associated with the highest mean hospital cost, length of stay, and highest proportion of early readmissions. Patients who received Tranexamic Acid had a significantly shorter length of stay, smaller likelihood of a blood transfusion, and no significant difference in hospital cost.
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Muller, Scott D. "The femoral cement mantle in total hip arthroplasty." Thesis, University of Newcastle Upon Tyne, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273507.
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Fu, Chun-him Henry, and 傅俊謙. "Outcomes of total knee replacement in young Chinese patients." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B48333840.
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Introduction:
This study aimed to assess the outcomes and implant survivorship in Chinese patients aged 55 years or younger.
Methods:
We reviewed our local joint replacement registry on a total of 102 knees from 68 Chinese patients aged 55 years or below at the time of surgery. All patients were operated on from January 2000 to July 2007. The mean followup was 8.3 years (range, 5 ? 12.5 years). We included patients with osteoarthritis (70 knees), rheumatoid arthritis (24 knees), hemophilia (4 knees), psoriatic arthropathy (1 knee), post?traumatic (1 knee) and tuberculosis (2 knees). All implants were cemented. 53 were posterior cruciate ligament (PCL) sacrificing, 47 were posterior stabilized implants and 1 was constrained implant. The preoperative and latest Knee Society Knee Scores, Knee Society Functional Score, knee range of motion and lower limb mechanical alignment on long film measurement were obtained. The postoperative occurrence of radiolucent lines, complications, revision operation and deaths were noted. Each knee was analyzed separately.
Results:
Mean Knee Society Knee Score improved from 41 (range: 13?79, SD 12.9) to 88 (range: 30?100, SD 13.3)(p <0.0001), while the mean Knee Society Functional Score improved from 41 (range: 0?80, SD 19.2) to 69 (range 0?100, SD 26.5 ) (p<0.0001). 70% achieved a postoperative coronal mechanical axis of within 3 from neutral alignment. Implant survivorship was 97% at 5 years and 85% at 10 years. 11 knees from 9 patients had complications requiring revision surgery. Aseptic loosening occurred in 10 knees of 8 patients. Among those with aseptic loosening, 3 knees from different patients had coexisting osteolysis. Heterotopic ossification occurred in 1 knee. There were no cases of infection.
Rheumatoid arthritis patients when compared with osteoarthritis patients had a more valgus preoperative lower limb alignment (p<0.001), a lower mean preoperative KSFS (30 and 45 respectively, p=0.004) and a lower mean postoperative KSFS (53 and 74 respectively, p=0.006). There were no significant differences in mean improvement of KSFS, KSKS, radiological outcomes and implant survival.
There were no statistically significant differences in clinical outcomes, radiological outcomes and implant survival between PCL sacrificing and PCL substituting implants.
There were no statistically significant differences between the postoperatively neutrally aligned group and the outlying group in terms of clinical outcomes, radiological outcomes and implant survival.
Conclusion:
Total knee arthroplasty provides good clinical and functional outcomes in young Chinese comparable to those of international standards. Careful patient selection is crucial to avoid complications.published_or_final_version
Orthopaedics and Traumatology
Master
Master of Medical Sciences
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Fisher, Emily Kay. "SYSTEMATIC REVIEW OF OUTCOMES OF TOTAL JOINT REPLACEMENT CLASS PARTICIPATION." Kent State University Honors College / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ksuhonors1367924351.
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Ollivere, Benjamin. "Osteolysis in total joint replacement : are patient factors important?" Thesis, University of East Anglia, 2010. https://ueaeprints.uea.ac.uk/36323/.
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Kipping, Michael. "Wear and degradation of UHMWPE total hip replacement components." Thesis, University of Nottingham, 2009. http://eprints.nottingham.ac.uk/14468/.
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Long term (>2 years) failure of UHMWPE components in-vivo is predominantly caused by wear of the UHMWPE component. The surface properties of UHMWPE greatly influence the adhesive and abrasive mechanisms of wear that occur in the hip. However, there is not a clear understanding of how in-vivo wear mechanisms influence surface mechanical properties of UHMWPE. In addition, previous researchers have reported wear rates for Charnley UHMWPE acetabular components that vary considerably between patients. It is conceivable that these variations in wear are a result of variations in the surface mechanical properties of UHMWPE. This study used a combination of instrumented indentation testing and Ff-IR imaging to assess the depth dependent micromechanical and chemical properties of 32 retrieved UHMWPE acetabular components. Significant variations in the mechanical and chemical properties of samples taken from worn and unworn regions of retrieved UHMWPE acetabular components were found. In unworn regions, these variations were principally caused by post-irradiation ageing. However, in worn regions, the variation in properties was primarily caused by the wear process.
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Naylor, Jason Richard. "Biomechanical evaluation of CAdisc-L total disc replacement implant." Thesis, University of Nottingham, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.587835.
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Degenerative disc disease (DDD) is a natural degenerative process that affects the intervertebral discs of the spine and is a major cause of lower back pain. After failure of conservative measures DDD may be treated surgically by fusion or Total Disc Replacement (TOR). Fusion results in loss of motion at the operated level, causing increased motion at adjacent levels. This is thought to accelerate further degenerative changes. The intention of TOR is to replace the disc and maintain normal motion in the spine. CAdisc-L is a novel TOR implant; it preserves motion by deforming under load rather than articulating like existing devices. The objective of the study was to ascertain the effect of implantation of CAdisc-L on sagittal biomechanics. Spine specimens were tested before and after implantation to asses implant stiffness, range of motion and stability. Additionally the position and migration of the Instantaneous Axis of Rotation (IAR) of the specimens was recorded. Finally, the ultimate failure load of implanted specimens in compression was evaluated. Monosegmental cadaveric spine specimens were used for the study. Loads and moments were applied by a uni-axial test machine and movement of the specimen was captured using reflective markers and a motion tracking camera. Implantation resulted in a reduction in compressive stiffness, but an increase in overall disc height which maintained the intervertebral space in compression up to 4.4kN. A reduction in flexural stiffness was seen after implantation as well as a reduction in neutral zone. Tracking of the IAR of the specimen indicated that it migrated by a similar range to intact specimens both horizontally and vertically. The position of the IAR was displaced posteriorly my 5.2mm at 6° of flexion compared to intact specimens. Ultimate failure loads were not found to be affected significantly.
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Poon, Mei-ying Dora, and 潘美英. "Gait analysis of normal and total knee replacement subjects." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B31214563.
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Wilson, Julie Kay. "A comparative study of rehabilitation on total knee replacement." Virtual Press, 1995. http://liblink.bsu.edu/uhtbin/catkey/1014843.
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The purpose of this study was to determine the effectiveness of the Augmented Soft Tissue Mobilization (A.S.T.M.) Rehabilitation Technique on total knee replacement patients. The specific measurements assessed were stride length (SL), stride frequency (SF), walking velocity, support time (ST), total time (TT), static and walking range of motion (ROM) of the hip, knee, and ankle, ground reaction forces (GRF), and torques. Fourteen subjects (Female = 7, Male = 7) completed the study. Subjects were randomly assigned to two experimental groups, the Traditional Therapy treatment or the A.S.T.M. treatment. There were five testing sessions: pre operation, 8 weeks, 12 weeks, 16 weeks, and 24 weeks post operation. On the 12 week test, the subject had completed their assigned of treatment protocol. Static ROM was derived from gonimetric measurements before each testing session. Stride length, stride frequency, velocity, time, and walking ROM were derived from accelerometer data. Statistical analysis using ANOVA revealed a significant change in all static ROM, SL, and ST. The data indicated that both groups of the Total Knee Replacement patients did improve their functional status from their status prior to surgery. In addition, the data indicated that the Augmented Soft Tissue Mobilization program and the Traditional Therapy program are equally acceptable rehabilitation techniques.School of Physical Education
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Fogarty, Declan James. "Postoperative analgesia following spinal anaesthesia for total hip replacement." Thesis, Queen's University Belfast, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261938.
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Auger, Daniel D. "Tribology of 'cushion bearings' used for total joint replacement." Thesis, University of Leeds, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417538.
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Zant, Nikolaus Peter. "Fatigue integrity of reconstructed acetabula in total hip replacement." Thesis, University of Portsmouth, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438851.
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Foley, Elizabeth Louise. "Tibial rotation in patients after total knee joint replacement." Thesis, University of Strathclyde, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248949.
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Fong, Yin Ki Kiki. "Characterisation of polyetheretherketone for use in total knee replacement." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/412400/.
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A polymer-based total knee replacement (TKR) system that utilises an injection moulded polyetheretherketone (PEEK) femoral component has been proposed. The current project was designed to characterise the material at the coupon level by acknowledging the issues related to the processing route as well as the in-service conditions of the proposed component. Surface characterisation (wide angle X-ray scattering (WAXS), nanoindentation, atomic force microscopy (AFM) and photographic image processing) showed that heterogeneity was introduced to the material as a result of differential cooling that occurred during injection moulding. The crystallinity level and the nanoindentation hardness were highest at the core of the sample and lowest at the surface. These were visible as variation in shading on the cross-section of the sample. Although these findings supported the presence of an amorphous surface layer, the lack of abrupt change in properties from surface to bulk meant that its thickness could only be estimated (318m to 545m) and could not be more accurately gauged. Nonetheless, the findings showed that the mechanical properties of the amorphous surface layer were lower than that of the bulk. While this could possibly be deleterious by promoting uid ingress in-service, it could also potentially be beneficial as it might provide a crack-shielding effect to the proposed TKR femoral component. Mechanical characterisation showed that the static response of the material was rate sensitive at the coupon level, but not at the nano-scale. This could be related to the difference in global and local responses, but also attributed to the difference in the mode of testing. The design and the execution of a multi parameter fatigue test programme has successfully demonstrated how the effects of test parameters on the material could be studied in a strategic manner. Failure limits were identied, where samples failed (predominantly due to cyclic softening) as opposed to running out. The fatigue life of the material was shortened by (i) increasing the stress level, (ii) increasing the frequency, (iii) suppressing cooling, and (iv) using a sinusoidal waveform instead of a waveform taken from TKR knee contact force data from the OrthoLoad database. These suggest that testing at 5Hz using a sinusoidal waveform in an ambient environment would be a suffciently effcient and robust test method for the proposed TKR femoral component, and the developed method may be used to identify appropriate characterisation methods for other novel implants.
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Okoro, Tosan. "Optimising patient function following elective total hip replacement surgery." Thesis, Bangor University, 2013. https://research.bangor.ac.uk/portal/en/theses/optimising-patient-function-following-elective-total-hip-replacement-surgery(11a74fb6-a659-42c1-9333-dbc5e42c3a89).html.
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Symptomatic hip osteoarthritis is associated with poor general health status and surgical intervention (total hip replacement; THR) is the most effective treatment for end stage disease. This procedure generally resolves pain, but function usually remains substantially sub-optimal. This protracted disability has detrimental economic, social and health consequences. 'Standard rehabilitation' (SR), (i.e. low intensity exercise, not involving progressive resistance training (PRT)), typically permits patients to regain basic levels of function but fails to resolve the significant muscle wasting and subsequent strength deficits associated with the condition. Supervised PRT following THR produces good results in terms of muscle strength and function. However, delivery of this type of program is expensive due to the high costs associated with supervision, facility provision, and transport of patients. A home-based program featuring relatively high intensity PRT but not requiring a high degree of supervision, would potentially overcome these problems. Before commencing this study, evidence was lacking regarding whether home-based PRT regimes with weekly supervision in the early postoperative period were effective in restoring muscle mass and physical function in THR patients.
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Isaac, Graham Hugh. "The tribology of bearings used in total hip replacement." Thesis, University of Leeds, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.713498.
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This thesis focusses on the dominant theme at my research activity, the triboiogy of bearings for use in Total Hip Replacement. This theme covers the majority of my research projects and hence publications to date. Restricting the research that is covered has the benefit of focusing the summary into a narrative which formed part of the worldwide research effort in this area. It does however mean that some of the more esoteric projects, such as the work on baby's dummies, were not included. . For those interested in this field or merely curious, the reference (6) has been included in the list of citations attached to this document.
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Jiang, Wei. "Wear measurement of polyethylene components in total knee replacement." Thesis, University of Leeds, 2014. http://etheses.whiterose.ac.uk/7910/.
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The total knee replacement (TKR) was designed to provide final-stage treatment for patients to replace the damaged biological tissues and help the patient to carry out daily normal activities. Determination of wear of the polyethylene knee inserts has been an important subject in improving the longevity of TKR. Accurate wear measurement methodologies are essential to differentiate between the performance of different materials and designs because the geometry changes can be small and can consist of both wear and creep. The aim of this study was to develop a coordinate based threedimensional volumetric determination methodology using CMM and Micro-CT measurement techniques. The validation of the methodology was carried out using a FE model and computational volume removal test. Afterwards, the volumetric determination method was used to calculate the volume loss from computational and experimental tests of volume removal and creep deformation. Finally, the methodology was applied to evaluate both simulator and retrieval specimens. The studies indicated the presented volumetric determination methodology was not dependent on pre-wear data, CAD model or original design drawings and can be used for both simulator and retrieval analysis at relevant levels of wear and creep. It can also be applied to the biotribological study of other polyethylene components, since wear and damage can be assessed visually and volumetrically. The comparison between CMM and Micro-CT methods suggested that the CMM has higher accuracy and better repeatability. Whilst the methods developed in this thesis were suitable for laboratory and computational wear determination, they are not suitable for all specimens in retrieval study due to the greater amount of wear and damage on the surface.
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Zhang, Yin, and 張銀. "Validation of the new knee society knee scoring system for outcome assessment after total knew arthroplasty." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/193564.
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Introduction:
This retrospective comparative study was to define the validity and reliability of a translated, culturally adapted Chinese version questionnaire of the New Knee Society Knee Scoring System (NKSS).
This study is aim to investigate the validity and reliability of the translated Chinese version of the NKSS and assess its feasibility of measuring the scale on Chinese patients by performing its cross-cultural adaptation for patients after Total Knee Arthroplasty (TKA) in Hong Kong.
Methods:
A total of 104 knees from 64 Chinese patients performed TKA were included in the study using the translated, culturally adapted Chinese version of the NKSS. All Patients were operated on from October 2010 to May 2013 at Queen Mary Hospital. Patients who participated in this study have been clinically screened and established a set of including criteria. The outpatients were evaluated by completing the five questionnaires containing the NKSS, the Knee Society Clinical Rating System (KSS), Medial Outcomes Study 36+Item Short Form (SF-36), Bristol Knee Score and Oxford Knee Score.
Reliability was evaluated using the Split-half reliability, Chronbach's α coefficient and inter-item correlation. To assess validity, all patients filled in the same NKSS questionnaire, and previously validated Chinese version of the SF-36, Bristol Knee Score and Oxford Knee Score. The validity was determined with Content Validity and Contract Validity.
Results:
The NKSS showed ideal split-half reliability as evidenced by the high correlation coefficient (R>0.7, P<0.05). Chronbach's α coefficient for five major domains demographics, objective knee score, expectations, satisfaction and function was high (α>0.7. P<0.05). Also, the inter-item correlation was also excellent for all domains. For validity, the NKSS was found to have excellent correlation with Bristol Knee Score and Oxford Knee Score, good correlation with KSS and SF 36
Discussion:
The NKSS as a validated approach is adapted to the diverse health-related quality of lives and activities of contemporary patients with TKA. Orthopaedics surgeons are allowed to appreciate differences in the priorities of individual patients and the interplay among function, expectation, symptoms, and satisfaction after TKA using this assessment instrument.
Conclusion:
The results of this study show that the NKSS as a functional status questionnaire has been translated into Chinese without missing any psychometric properties of the original version. This culturally and linguistics adapted Chinese version of the NKSS outcome assessment has satisfactory internal consistency and good validity. It is an adequate and helpful instrument for the evaluation of Chinese speaking patients after TKA in clinical studies.published_or_final_version
Medical Sciences
Master
Master of Medical Sciences
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Sandell, Claire-Louise. "A study of self-reported surgical site infection post total hip or total knee replacement." Thesis, University of Portsmouth, 2012. https://researchportal.port.ac.uk/portal/en/theses/a-study-of-selfreported-surgical-site-infection-post-total-hip-or-total-knee-replacement(ff96dda8-7c00-4e3a-8de2-ade5c54bfd02).html.
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Background: Currently there is little published evidence exploring the experience of post discharge surgical patients who have developed infection following hip and knes joint surgery. This mixed methods syudy used both quantitative (Phase One) and qualitative (Phase Two)methodologies to explore the experience of patients with self-reported surgical site infection Methods: Phase One - Used a researcher developed postal questionnaire to identify the incidence of self-reported surgical site infection at six weeks post surgery as well as investigating the patients' experience of diagnosis, treatment and outcome following surgical site infection. Phase Two - Recruited from Phase One, twenty three patients were recruited from Phase One and invited to participate in one to one unstructured, audio taped qualitative interviews. Guided by Husserlian phenomenological approach to data collection and analysis informed by Colaizzi's method of data analysis, nine patients shared their lived experience of developing an infection post surgery. Findings: Phase One - A total of 523 patients were identified at one NHS trust and after exclusions questionnaires and stamped addressed envelopes were posted 505 patients six weeks following either total hip or total knee replacement surgery. A reponse rate 88.5% led to a final analysis of 447 questionnaires to reveal that 23 (or 5.1%)patients developed a surgical site infection, 7 in total hip replacement and 16 in total knee replacement patients. Ten infections were identified prior to discharge and 13 post discharge. Only 6 of the 23 patients were first seen by a hospital practitioner after suspecting a surgical site infection. 4 patients sought review by their general practitioner, who then referred them on to a hospital pratitioner. The remaining 13 patients utilised a combination of different management pathways. In Phase Two analysis of the nine verbatim transcriptions revealed 5 main themes of (1) Vulnerability, (2) Perception of infection, (3) Significant event, (4) Yo yoing and (5) Pendulum of care. Dicussion: Comparisons between current surveillance methods and those utilised in the study identified that current surveillance methos are likely to under represent the total number of self-reported surgical site inf
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Neander, Gustaf. "Displaced femoral neck fractures : studies on osteosynthesis and total hip arthroplasty /." Stockholm, 2000. http://diss.kib.ki.se/2000/91-628-4167-X/.
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Taylor, Cindy. "The role of hope on outcomes following total knee replacement." Thesis, University of Leicester, 2011. http://hdl.handle.net/2381/9901.
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Total hip and knee replacement are increasingly common elective surgical procedures in the UK, performed primarily for the relief of osteoarthritis in the majority of cases. Research has shown that individual psychological variables play a part in determining outcomes following these procedures. The literature review systematically examined the role played by patient expectations in outcomes following total hip and knee replacement. In addition, it examined the way in which both expectations and outcomes were conceptualised and measured in the literature. Finally, it sought to determine the theoretical underpinnings of expectations research. With the exception of one study, results showed that expectations do influence outcome. Weaknesses were identified in respect to the inconsistent approach used to measure both outcomes and expectations. A lack of theoretical underpinning of expectations was noted. Expectations may have implications for informing surgical selection and prognosis. Suggestions for future research in this area were made. The empirical study examined the role that hope might play in determining outcomes following primary total knee replacement for osteoarthritis. Much previous research in this area has been conducted from a deficit model of health. In contrast, hope is a positive psychological construct, which identifies and builds on individuals’ strengths. Pre-operative hope did not, as expected, directly influence outcome after surgery. It was found however, to be a significant unique predictor of pre-operative psychological morbidity and physical function, accounting for 9% and 10% of variance respectively. Both depression and function have been shown to influence outcome in this population. It could be argued that the pre-operative period is when the impact of osteoarthritis is most significant. Hope may be an important factor in delivering effective condition management at this time. Suggestions for future research and possible interventions based on these findings were advanced.
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Agarwal, Yash. "Finite element modelling for stability of a total knee replacement." Thesis, University of Surrey, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.594269.
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The use of, and interest in, total knee replacements (TKR) has been growing over the last few decades. Loosening and migration of tibial components have been identified as one of the primary causes of failure in the proximal tibia. Clinical studies show the use of metal implants as one of the primary methods for the treatment of knee joints and associated bone defects. Alignment and fixation techniques play an important role in achieving high success rates. Defective bone stock requires the use of augments to stabilise the tibial plate. In these cases, current clinical practice is to use an extended implant stem to ensure stability. The problem with this is that it reduces the potential for future knee revision In this research Finite Element Analysis (FEA) has been used to undertake virtual in-vivo assessment of various configurations of augmented and non-augmented TKR that can be used for the treatment of tibial defects. These configurations are based on a standard tibial insert, namely a fIxed bearing revision tibial tray. This has provided insight and information that can be used to improve surgical decision making when dealing with defective bone stock. The 3D FE models of a non-defect TKR with a fixed bearing tibial insert showed a stable construct with stresses lying within an allowable threshold. The use of a stem extension generally showed a reduction in stress levels in the cancellous bone contributing to an increase in stress shielding and thus it is recommended that these are not used unless there is some other overriding clinical requirement. Further, the analysis demonstrated that, contrary to some clinical opinion, wedge augmentation (rather than block augmentation) may provide a better approach to treat the defect. This was largely due to improved cement stress distribution caused by a mechanism termed "reverse-shear". The use of a cement augment was found to provide a more favourable stress distribution in the cancellous bone. However, metal augments have been recommended as the cement augment was shown to operate too close to its fatigue endurance limits. Future work should focus on further enhancements of the bio-fidelity of the FE model particularly in the material distribution. The idealisation of the cancellous bone as a uniform isotropic material can be improved to provide a spatially varying distribution of material properties, reflecting the natural variation in bone density. Another aspect to further enhance this work would be to extend the applied loads to reflect other lower body movements and to consider the effect of friction at the condyles on the anterior-posterior load applied.
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Otoum, Nesreen. "Medical image processing : applications in ophthalmology and total hip replacement." Thesis, Loughborough University, 2013. https://dspace.lboro.ac.uk/2134/11848.
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Medical imaging tools technologically supported by the recent advances in the areas of computer vision can provide systems that aid medical professionals to carry out their expert diagnostics and investigations more effectively and efficiently. Two medical application domains that can benefit by such tools are ophthalmology and Total Hip Replacement (THR). Although a literature review conducted within the research context of this thesis revealed a number of existing solutions these are either very much limited by their application scope, robustness or scope of the extensiveness of the functionality made available. Therefore this thesis focuses on initially investigating a number of requirements defined by leading experts in the respective specialisms and providing practical solutions, well supported by the theoretical advances of computer vision and pattern recognition. This thesis provides three novel algorithms/systems for use within image analysis in the areas of Ophthalmology and THR. The first approach uses Contourlet Transform to analyse and quantify corneal neovascularization. Experimental results are provided to prove that the proposed approach provides improved robustness in the presence of noise, non-uniform illumination and reflections, common problems that exist in captured corneal images. The second approach uses a colour based segmentation approach to segment, measure and analyse corneal ulcers using the HVS colour space. Literature review conducted within the research context of this thesis revealed that there is no such system available for analysis and measurement of corneal ulcers. Finally the thesis provides a robust approach towards detecting and analysing possible dislocations and misalignments in THR X-ray images. The algorithm uses localised histogram equalisation to enhance the quality of X-ray images first prior to using Hough Transforms and filtered back projections to locate and recognise key points of the THR x-ray images. These key points are then used to measure the possible presence of dislocations and misalignments. The thesis further highlights possible extensions and improvements to the proposed algorithms and systems.
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Hansen, David John S. M. Massachusetts Institute of Technology. "Developing a total replacement cost index for suburban office projects." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/37441.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Architecture, 2006.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (leaves 78-79).
Understanding the components of replacement costs for office developments, and how these components combine to create total development costs is essential for success in office real estate development. Surprisingly, the term "replacement cost" does not enjoy a standard definition in the industry. This study explores the components of total replacement cost, and ultimately creates a market-level index industry professionals can utilize when creating or reviewing office development budgets.
by David John Hansen.
S.M.
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Techamahamaneerat, S. "Psychological factors and experience of patients undergoing total hip replacement." Thesis, Liverpool John Moores University, 2016. http://researchonline.ljmu.ac.uk/4572/.
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This study aimed to comprehensively explore the relationship between psychological factors and pain, function and quality of life. A mixed method approach comprising two longitudinal and one cross-sectional elements, was conducted, with results being triangulated to give a multi-perspective view of the relationships. In the longitudinal elements, the questionnaire used in the quantitative phase was developed from validated tools, with cognitive interviews incorporating a think-aloud technique, used to validate the questionnaire package. Diary and interview schedules for the qualitative phase were developed from the existing literatures in this field. Additionally, a cross-sectional review of the pre-operative education programme in five centres was examined through participant observation. One-hundred and five patients scheduled for initial assessment were recruited into the quantitative phase. Of these, thirty-nine were successfully recruited to the quantitative phase and sixteen were followed up at six months post-operative. Twelve of the participants in the quantitative phase also participated in the qualitative phase, with five being successfully followed up at six months post-operative. Results indicated that pain, function and quality of life were highly associated with self-efficacy, pain catastrophising, functional expectations, pre-operative depression, post-operative anxiety and post-operative negative affect. The qualitative element identified five themes: physical symptoms; management and awareness; support; well-being; and cognitive aspects of the self-regulatory model. Evaluation of the content of the education programme identified that all information provided to the patients was in line with the guidelines. Triangulation of the mixed methods identified the congruence of major relationships between pain, function and quality of life with self-efficacy and expectations in the longitudinal elements. Self-efficacy and expectations should be considered throughout the hip surgery journey. Interventions, such as use of a reflective diary and talking to former patients who have undergone hip replacement, will enhance self-efficacy and adjustment of expectations, thus promoting better pain control, functional recovery and helping to tackle negative emotions.
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Ascani, Daniele. "Individualised modelling for preoperative planning of total knee replacement surgery." Thesis, University of Sheffield, 2016. http://etheses.whiterose.ac.uk/16044/.
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Total knee replacement (TKR) surgery is routinely prescribed for patients with severe knee osteoarthritis to alleviate the pain and restore the kinematics. Although this procedure was proven to be successful in reducing the joint pain, the number of failures and the low patients’ satisfaction suggest that while the number of reoperations is small, the surgery frequently fail to restore the function in full. The main cause are surgical techniques which inadequately address the problem of balancing the knee soft tissues. The preoperative planning technique allows to manufacture subject-specific cutting guides that improves the placement of the prosthesis, however the knee soft tissue is ignored. The objective of this dissertation was to create an optimized preplanning procedure to compute the soft tissue balance along with the placement of the prosthesis to ensure mechanical stability. The dissertation comprises the development of CT based static and quasi-static knee models able to estimate the postoperative length of the collateral lateral ligaments using a dataset of seven TKR patients; In addition, a subject-specific dynamic musculoskeletal model of the lower limb was created using in vivo knee contact forces to perform the same analysis during walking. The models were evaluated by their ability to predict the postoperative elongation using a threshold based on the 10 % of the preoperative length, through which the model detected whether an elongation was acceptable. The results showed that the subject-specific static model is the best solution to be included in the optimized, subject-specific, preoperative planning framework; full order musculoskeletal model allowed to estimate the postoperative length of the ligaments during walking, and at least in principle while performing any other activity. Unlike the current methodology used in clinic this optimized preoperative planning framework might help the surgeon to understand how the position of the TKR affects the knee soft tissue.
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Dopico, Gonzalez Carolina. "Probabilistic finite element analysis of the uncemented total hip replacement." Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/68694/.
Full textAbstract:
There are many interacting factors aecting the performance of a total hip replacement (THR), such as prosthesis design and material properties, applied loads, surgical approach, femur size and quality, interface conditions etc. All these factors are subject to variation and therefore uncertainties have to be taken into account when designing and analysing the performance of these systems. To address this problem, probabilistic design methods have been developed. A computational probabilistic tool to analyse the performance of an uncemented THR has been developed. Monte Carlo Simulation (MCS) was applied to various models with increasing complexity. In the pilot models, MCS was applied to a simplied nite element model (FE) of an uncemented total hip replacement (UTHR). The implant and bone stiness, load magnitude and geometry, and implant version angle were included as random variables and a reliable strain based performance indicator was adopted. The sensitivity results highlighted the bone stiness, implant version and load magnitude as the most sensitive parameters. The FE model was developed further to include the main muscle forces, and to consider fully bonded and frictional interface conditions. Three proximal femurs and two implants (one with a short and another with a long stem) were analysed. Dierent boundary conditions were compared, and convergence was improved when the distal portion of the implant was constrained and a frictional interface was employed. This was particularly true when looking at the maximum nodal micromotion. The micromotion results compared well with previous studies, conrming the reliability and accuracy of the probabilistic nite element model (PFEM). Results were often in uenced by the bone, suggesting that variability in bone features should be included in any probabilistic analysis of the implanted construct. This study achieved the aim of developing a probabilistic nite element tool for the analysis of nite element models of uncemented hip replacements and forms a good basis for probabilistic models of constructs subject to implant position related variability.
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Stratton-Powell, Ashley Alexander. "On the failure of total ankle replacement : a retrieval analysis." Thesis, University of Leeds, 2018. http://etheses.whiterose.ac.uk/20588/.
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Total ankle replacement (TAR) has been under development for 40 years but is not considered as successful as other lower limb total joint replacements (TJR). The failure rate of TAR is more than double that of total hip replacement at 10 years, yet the failure mechanisms remain largely unknown. The research in this thesis aimed to identify the wear modes and possible origins of failure for a cohort of failed TARs using a retrieval analysis approach. Explants, medical imaging and periprosthetic tissue samples were retrieved for 44 participants following revision TAR surgery. Five TAR brands were retrieved, all of which were uncemented, three-component, mobile-bearing designs. Each resource was investigated using established and novel retrieval analysis methods including, but not limited to: photogrammetry, microscopy, non-contacting 3D surface profilometry, computed tomography and wear particle isolation. Ballooning osteolysis was highly prevalent. Component alignment was within alignment variations considered acceptable in the published literature, yet high rates of edge-loading (70.5%) and impingement (57%) were evident. Fixation and bearing surface wear affected 98% of tibial components. The volumetric wear rate for eight bearing inserts was 2.5 times higher than the greatest wear rate reported by in-vitro simulation studies. Hydroxyapatite wear particles were micron-sized with a high aspect ratio (AR = 3.7). Flake-like micron-sized cobalt chromium alloy and large titanium wear particles (>10 μm) were also isolated and characterised. The total wear particle population for TAR was generally larger and more elongated than the wear particle characteristics identified for other TJRs. Edge-loading, bearing insert subluxation and impingement contributed to wear modes 2, 3 and 4, which indicate device dysfunction and should be minimised by design. Mobile-bearing constraint, cortical window surgical approach and the rapid accrual of wear particles may be important contributors to the failure of TAR.
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Washington, Angela. "Management of Postoperative Pain in the Total Joint Replacement Patient." ScholarWorks, 2018. https://scholarworks.waldenu.edu/dissertations/5594.
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Managing postoperative pain continues to be a challenging public health problem. The organization under study was experiencing a prolonged length of hospital stay (LOS) in the post-total knee and hip replacement surgery population that was causing system-wide patient flow issues. The purpose of this quality improvement project was to educate patients through an established education class on pain expectations, strategies on managing pain, discharge planning, and physical therapy expectations with a goal of reducing pain and LOS. The health belief model was used as a guide to incorporate new content into the educational program that addressed patient knowledge on pain, concerns, fears, and misconceptions related to surgery. New content was added to the class on strategies to improve postoperative pain to help the organizational need to meet 2- to 3-day LOS. The project compared differences in pain levels and LOS in participants who completed the preoperative education and those who did not. The project methodology was a retrospective nonexperimental pretest and posttest design, and a quantitative analysis was used to compare pain levels measured by visual analog scale in documented charts during hospital stay. LOS was measured from data collected from chart review. The findings revealed lower pain levels during the hospital stay of those who completed the educational program. The patients who did not attend the class had an average mean LOS of 5 days as compared to 3 days LOS for those who attended the preoperative class. The project impacts social change on an organizational level by demonstrating that patients undergoing joint replacement surgery benefit from the revised educational plan, which results in early mobility, better pain control, and decreased LOS.
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Molloy, Martin-Patrick. "The biomechanics of the knee of total knee replacement golfers." Thesis, Ulster University, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.625503.
Full textAbstract:
Total knee arthroplasty (TKA) - the replacement of the articulating surfaces of the knee joint - is an increasingly used intervention for osteoarthritis. Younger, more active patients are undergoing TKA due to the clinical success of the implants. Surgeons must make recommendations on the suitability of post-surgery sporting activities; a balance must be struck between the health-promoting nature of the activity and the risk involved to the implant. Golf has been identified as a sport with a large number of participants that is recommended by the majority of knee surgeons. Despite golf being considered a low risk activity, there is limited scientific evidence that the loading applied to the knee-joint may be larger than assumed. Thus, the main aim of this thesis was to provide objective biomechanical data to contribute to our scientific knowledge base and to provide meaningful clinical data to enable medical practitioners to make informed decisions regarding the appropriateness of golf as an activity for post -TKA individuals. Three studies are presented in this thesis. The first investigated the suitability of a standard six-degrees-of-freedom (6DoF) marker model and tested the performance of an alternative model that included an 'optimised', modified cluster design placed on a site of low soft tissue artefact. Whilst statistically significant differences were identified between knee angles derived from each cluster design, the magnitude of the differences were small. Thus, both of the marker models were considered to provide knee-angle measurements that would be considered equivalent in a clinical setting.
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Yoshida, Yuri. "Gait patterns one year after unilateral total knee arthroplasty." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 76 p, 2006. http://proquest.umi.com/pqdweb?did=1292460001&sid=4&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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