A dissertation Master of Science in nursing education / Integrated care pathways (ICP’s), for total knee arthroplasty (TKA) and partial knee arthroplasty (PKA) have been used successfully in the last two decades. ICP’s have been known among other terms as ‘critical care pathways’, ‘algorithms of care’, ‘patient care pathways’, ‘collaborative care pathways’. The main aims of an ICP is that it coordinates the efforts of the members of the multi-disciplinary team through the alignment of the objectives of patient care processes. It improves outcomes of care and patient satisfaction is supported by comprehensive patient information provision both verbally and written. It is generally accepted that ICPs have an impact on the length of stay of patients in hospital, thus further enhancing the feeling of wellbeing of patients but also significantly contributing to the cost of surgery, care and rehabilitation. (Schuur et al, 2011). / MT2017

There is a need for a repeatable method of measuring polyethylene wear in total knee re-placement (TKA). Model-based radiostereometric analysis (MBRSA) is a high accuracy diagnostic tool with the potential to meet this need; however, a number of unknowns must be examined. This research examines optimized patient positioning for MBRSA imaging as well as in vitro validation of a wear measurement technique using a loaded TKA phantom to mimic patient physiology. Imaging along the antero-posterior and medio-lateral axes of the patient achieved op-timal MBRSA accuracy of better than 0.035 mm (in-plane) and 0.12° (in-plane). The de-veloped MBRSA technique underestimated TKA wear on previously-worn polyethylene bearings; however, a number of factors can be corrected to improve this discrepancy. This research provides an overall methodology for measuring TKA wear, but additional experimentation and an improved physiological phantom are needed to obtain accurate wear measurement.

There is a need for a repeatable method of measuring polyethylene wear in total knee re-placement (TKA). Model-based radiostereometric analysis (MBRSA) is a high accuracy diagnostic tool with the potential to meet this need; however, a number of unknowns must be examined. This research examines optimized patient positioning for MBRSA imaging as well as in vitro validation of a wear measurement technique using a loaded TKA phantom to mimic patient physiology. Imaging along the antero-posterior and medio-lateral axes of the patient achieved op-timal MBRSA accuracy of better than 0.035 mm (in-plane) and 0.12° (in-plane). The de-veloped MBRSA technique underestimated TKA wear on previously-worn polyethylene bearings; however, a number of factors can be corrected to improve this discrepancy. This research provides an overall methodology for measuring TKA wear, but additional experimentation and an improved physiological phantom are needed to obtain accurate wear measurement.

No description available.

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.

There is no published research available that evaluates the outcome of TKA in South African public hospitals. Prior to this project, there was no South African published research on the role of physiotherapy in patients post TKA. There are also no clinical practice guidelines in South Africa for rehabilitation post TKA. International guidelines may not be appropriate within a South African public hospital context. One of the issues raised in the literature pertaining to CPG development is that they lack practical detail and clarity of how decisions are made. In the current context, these problems may be compounded due to the lack of published research in the field in South Africa. The report that is presented is an attempt to combat these issues when a CPG for physiotherapy post TKA in a South African public hospital is developed. The aim of this study was to draft a report that could inform a comprehensive physiotherapy intervention (in the form of a clinical practice guideline) for patients undergoing a TKA in a tertiary care public hospital in urban South Africa. This was achieved through a series of four studies. The first study involved translating and establishing reliability of the Oxford Knee Score. The second study was a survey of current physiotherapy practice in the management of patients post TKA in South Africa. The third study was a prospective cohort study to establish the effect of an in-patient treatment protocol for use in the final study. The final study was an observational study to explore the outcome of patients post TKA and identify those who may be at risk for poor outcome. The English and translated versions of the Oxford Knee Score was shown to be reliable in this sample. This provided an outcome measure that can be used in the validation and evaluation phases of CPG development. The survey of current practice highlighted the high rate of staff turnover and the relative inexperience of physiotherapists working with patients post TKA in the public sector. It identifies the junior physiotherapists as potential stakeholders in the CPG. The trial of the in-patient physiotherapy protocol rendered similar findings to other similar studies in that a specific physiotherapy intervention did not have any effect on short term outcomes. It puts forward clear clinical questions to facilitate the development of the CPG, particularly relating to scheduling and delivery of weekend and out-patient therapy. The final study provided a demographic profile of the patients within the study context, who are potential stakeholders in the CPG development process. In addition it revealed that level of education, the presence of a caregiver at home, marital status and lack of previous exposure to physiotherapy form part of the profile of an ‘at risk’ patient. When the contribution that this thesis has made thus far to the CPG development process, is appraised using the AGREE tool, it shows that the thesis has contributed to 11 out of 23 of the criteria on the AGREE tool. It has therefore resulted in a report that informs the development of a clinical practice guideline for the physiotherapy management of patients post total knee arthroplasty in a tertiary care public hospital in Gauteng, South Africa.

No description available.

The conventional treatment for degenerative disc disease (DDD) and disc herniation is spinal fusion, a process consisting of fusing two segments of the spine together. Arthroplasty treatments that preserve the natural motion of the spine are still in the early stages of development. Cervical disc arthroplasty (CDA) involves removal of the existing damaged disc and replacement with an articulating implant. The materials used for implants must possess excellent biocompatibility, strength, and wear resistance properties. Spinal implants in particular should also allow precise post-operative imaging because surgeons rely on imaging tools to check for migration of the implant and nerve impingement post-operatively. The purpose of the current thesis is to investigate the wear behaviour of three different versions of poly-ether-ether-ketone (PEEK), a radiolucent polymer that does not distort MRI images, articulating against themselves. The materials tested include: PEEK OPTIMA (OPT), carbon-fiber reinforced (CFR) PEEK and carbon-nanofiber (CNF) PEEK. A series of wear tests were performed on a pin-on-plate apparatus that imposed reciprocating crossing-path motion to the articulating specimens. The first series of wear tests, “normal conditions tests”, consisted of application of 80 N for 2.0 million cycles (Mc). Continuation of testing was aimed at evaluating the tribological behaviour of the materials under “adverse conditions”. The adverse conditions involved increasing the load every 0.15 Mc until the material showed significant surface damage. The materials were tested in a 12g/L protein concentration alpha calf fraction serum, at 37˚C. The wear of the specimens were evaluated using volumetric wear calculations and microscopy. The lowest wear, at the end of the normal conditions test, occurred with the articulation of CFR PEEK-on-CFR PEEK, and the highest wear, after 2.0 Mc, occurred with CNF PEEK-on-CNF PEEK. The adverse conditions revealed the highest wear value for PEEK OPT. Surface damage was apparent on both the PEEK OPT and CFR PEEK specimens; however, volumetric wear measurements performed on the specimens did not indicate a rise in wear for CFR PEEK, though surface damage was visibly noted. CNF PEEK was not tested to failure, although surface damage was evident as the material neared the end of the adverse conditions test. The PEEK OPT wear values after the normal conditions test are similar to those reported for spine simulator studies on a PEEK OPT-on-PEEK OPT all-polymer lumbar nucleus implant. This tentatively suggests that the normal test conditions represent a clinically realistic range. CFR PEEK shows the most promise for application in cervical disc arthroplasty. The other versions of PEEK possess excellent imaging qualities but had inferior wear resistance compared with CFR PEEK. However, wear volumes found in the present thesis for all three versions of PEEK after the “normal conditions” test were considerably lower than those found for stainless steel (SS) in similar testing. Prestige® STLP, composed of SS, is an FDA approved product that is currently implanted in patients in the United States.

The conventional treatment for degenerative disc disease (DDD) and disc herniation is spinal fusion, a process consisting of fusing two segments of the spine together. Arthroplasty treatments that preserve the natural motion of the spine are still in the early stages of development. Cervical disc arthroplasty (CDA) involves removal of the existing damaged disc and replacement with an articulating implant. The materials used for implants must possess excellent biocompatibility, strength, and wear resistance properties. Spinal implants in particular should also allow precise post-operative imaging because surgeons rely on imaging tools to check for migration of the implant and nerve impingement post-operatively. The purpose of the current thesis is to investigate the wear behaviour of three different versions of poly-ether-ether-ketone (PEEK), a radiolucent polymer that does not distort MRI images, articulating against themselves. The materials tested include: PEEK OPTIMA (OPT), carbon-fiber reinforced (CFR) PEEK and carbon-nanofiber (CNF) PEEK. A series of wear tests were performed on a pin-on-plate apparatus that imposed reciprocating crossing-path motion to the articulating specimens. The first series of wear tests, “normal conditions tests”, consisted of application of 80 N for 2.0 million cycles (Mc). Continuation of testing was aimed at evaluating the tribological behaviour of the materials under “adverse conditions”. The adverse conditions involved increasing the load every 0.15 Mc until the material showed significant surface damage. The materials were tested in a 12g/L protein concentration alpha calf fraction serum, at 37˚C. The wear of the specimens were evaluated using volumetric wear calculations and microscopy. The lowest wear, at the end of the normal conditions test, occurred with the articulation of CFR PEEK-on-CFR PEEK, and the highest wear, after 2.0 Mc, occurred with CNF PEEK-on-CNF PEEK. The adverse conditions revealed the highest wear value for PEEK OPT. Surface damage was apparent on both the PEEK OPT and CFR PEEK specimens; however, volumetric wear measurements performed on the specimens did not indicate a rise in wear for CFR PEEK, though surface damage was visibly noted. CNF PEEK was not tested to failure, although surface damage was evident as the material neared the end of the adverse conditions test. The PEEK OPT wear values after the normal conditions test are similar to those reported for spine simulator studies on a PEEK OPT-on-PEEK OPT all-polymer lumbar nucleus implant. This tentatively suggests that the normal test conditions represent a clinically realistic range. CFR PEEK shows the most promise for application in cervical disc arthroplasty. The other versions of PEEK possess excellent imaging qualities but had inferior wear resistance compared with CFR PEEK. However, wear volumes found in the present thesis for all three versions of PEEK after the “normal conditions” test were considerably lower than those found for stainless steel (SS) in similar testing. Prestige® STLP, composed of SS, is an FDA approved product that is currently implanted in patients in the United States.

Reverse shoulder arthroplasty is a relatively new procedure that is used to treat shoulders with massive rotator cuff tears combined with arthritis, a condition that is not well managed using conventional shoulder arthroplasty. By reversing the ‘ball-and-socket’ anatomy of the shoulder, the constraint of the joint can be increased. Despite the success of this prosthesis in improving pain and function, complication rates remain high and instability is often reported as the most commonly occurring complication. The mechanism of dislocation as well as factors that can be modified to decrease the risk of dislocation are not well understood for reverse shoulder arthroplasty. Therefore, the purpose of this study was to create a platform for examining the stability of reverse shoulder arthroplasty and use this to investigate factors affecting stability, including shoulder orientation (abduction and abduction plane angles), loading direction, glenosphere eccentricity and diameter, and humeral socket constraint. An anatomical shoulder simulator was developed using a synthetic bone model and pneumatically actuated cables to represent the three heads of the deltoid. A displacing force was applied to the humeral head by a material testing machine in an anterior, posterior, superior, or inferior direction. The force required to dislocate the joint was used as a measure of stability and the identified factors and the interactions between factors were examined using a half-fraction factorial design experiment. Increases in glenohumeral abduction or inferior-offset of the glenosphere were found to improve the stability of the prosthesis. Additionally, increased humeral socket depth resulted in greater stability for all loading directions, with the exception of inferior loading. Abduction plane angle and glenosphere diameter had no effect on the stability of reverse shoulder arthroplasty. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2011-12-23 11:42:21.592