The development of a vasculature within a tissue-engineered construct is one of the largest hurdles to successful bone regeneration. This thesis investigates methods to increase vasculature of such transplanted constructs, based on in vivo transplant studies and in vitro analysis of cell behaviors. A syngeneic mouse model in immunocompetent mice was developed and analyzed for both osteogenesis and hematopoiesis. This study demonstrates that syngeneic bone marrow stromal cells (BMSCs) are not rejected by the host, provided the strain of mice is sufficiently inbred. Additionally, an effective protocol was developed for the isolation of endothelial cells (ECs) from the bone marrow of mice. Two different sets of materials for this study were analyzed, both collagen based, and the GelfoamTM scaffold was found to possess advantages over synthesized collagen or collagen/hydroxyapatite composites, although only for mouse and not human bone transplantation. In order to gain rapid and integrated vasculature formation within the transplant, attempts were made to increase both (de novo) vasculogenesis and angiogenesis (ingrowth) from the surrounding tissue. For the former, transplant studies were combined with in vitro osteogenic calcification studies. Direct co-culture of the BMSCs and ECs increased osteogenic calcification and was monitored by using both alizarin red S quantification and quantitative polymerase chain reaction. Angiogenesis (as assessed by cell migration) was studied by various motility and chemotaxis assays in vitro, as well as through use of a directed in vivo angiogenesis assay. Growth factors, particularly TGF-β1 and BMP-4, were found to increase cell movement in these systems. In conclusion, we show that although much work remains to be done in order to increase the vasculature in bone transplants, systematic combination of in vivo and in vitro assays can elucidate the nature behind this crucial process in this context.

Thesis (MScPhysio (Interdisciplinary Health Sciences))--Stellenbosch University, 2008. / Introduction In clinical physiotherapy, there is a growing importance for the accuracy and reliability of assessment and outcome measures. The purpose of this study is to develop a valid outcome measure for orthopaedic trauma inpatients. Item generation was done by conducting a systematic review of published functional outcome measures and patients' interview. Item reduction was conducted by using a panel of physiotherapists and patients. Objectives The overall study objectives were: 1) To determine if a functional outcome measurement scale for trauma inpatients exists and has been published; 2) To generate functional items for the construction of a new outcome measurement tool for trauma inpatients; 3) To construct a new outcome measurement tool for trauma inpatients and assess elements of validity and reliability (face and content validity, response to change, internal consistency and floor and ceiling effects) of the new developed outcome measure. Methodology Convenience sampling was applied to collect data from 35 trauma inpatients in trauma wards at Rashid Hospital in Dubai, UAE. 88% of the trauma inpatients were male (total sample n= 100), mean age =34.75, and the standard deviation = 14.46. 21 functional activity items were generated from the collated results of the patient interviews. Internal consistency reliability, responsiveness and floor and ceiling effect were assessed. Data analysis was conducted using Statistica Version 7. Results The final number of functional activity items included in the newly developed Functional Scale outcome measure was 29 activity items relevant for trauma inpatients. A Cronbach's alpha ranged between 0.76 and 0.97. The lowest alpha result was for the 'ADL' activities at follow-up (0.76). The highest alpha result was for 'out of bed' activity at admission and discharge (0.97). The response to change of the Functional Scale for trauma inpatients over time results illustrates that there was a significant difference in the mean scores over three administrations of 'Bed', 'Out of bed' and 'ADL' activity items of Functional Scale for trauma inpatients (p=O.OOOO). In general, there was no significant floor and ceiling effects at admission or discharge for 'bed', 'out of bed' and 'ADL' activities, except there was a floor effect noted at discharge for 'bed' activities and 'ADL' activities, and a ceiling effect noted at admission for 'out of bed activities' only. Discussion and Conclusion The newly developed Functional Scale outcome measurement for trauma inpatients has been shown to be internally consistent and appears to be valid with respect to response to change in this sample of trauma inpatients. The results of this study thus suggest that the Functional Scale for trauma inpatients may be an appropriate tool when the goal is the assessment of change in disability functions in trauma inpatients, although further psychometric testing may be required.

This research project presents a study of the fixation of screws in augmented and non-augmented cancellous bone at a microscopic scale. It is estimated that somewhere close to one million screws are failing each year. Therefore, the aim is to identify the key parameters affecting screw pull-out in order to improve screw fixation in cancellous bone, and hence screw design. The background for this study comes from work by Stryker, comparing screw pull-out from augmented and non-augmented cancellous bone, where a few cases of screw pull-out gave better results without bone augmentation. This is contrary to most evidence and the hypothesis to explain these results is that the screw pull-out from cancellous bone could be strongly affected by the cancellous bone micro architecture. The effect of the influence of the screw’s initial position was first verified with 2D finite element (FE) models of screw pull-out from simplified cancellous bone models. The results showed a force reaction variation up to 28% with small change in position. The hypothesis was then tested with 3D FE models of screw pull-out from more complex cancellous bone models with different volume fractions. Three volume fractions were tested and again the effects were confirmed, but only in models with the lower volume fraction. A variation up to 30% of the force reaction was observed. The 3D simplified cancellous bone models with 5.3% volume fraction were also used to study the influence of augmentation using calcium phosphate cement. A significant improvement of the screw holding power (almost 2 times) as well as an important diminution of the variability of the pull-out force due to the screw initial position was found. Other augmentation geometries were used to model cement. They all showed an increase of the screw pull-out force reaction with an increase of the cement volume. Validation of FE results was achieved by comparing screw pull-out from a cadaver cancellous bone and the FE model constructed from the same bone sample. New studies were then carried out from the cadaver cancellous bone model. The first study examined the screw initial position influence with cancellous and cortical screws and again showed that there is a strong correlation between screw pull-out stiffness and bone volume fraction. The cortical screw showed improved performance over the cancellous screw. Augmentation cases were explored using three bone samples with a range of volume fractions obtained from different sites within the cadaver bone sample. The cancellous screw was tested with 3 types of augmentation and the cortical screw was tested with one augmentation in these 3 samples. The results showed each time a significant improvement of stiffness with augmentation but when compared with the effect of volume variation inside the bone sample, it appeared that the improvement of stiffness from augmentation might not cover the loss in stiffness from a small change in bone structure. Finally, screw design parameters were investigated, as cortical screws seemed to give as good or better stiffness results than cancellous screw. The thread pitch, the thread angle and the core diameter were analysed independently and it appeared that the most important parameter was the thread pitch with an improvement of the stiffness of +46% for cancellous screws with a smaller thread pitch. The two other factors studied (core diameter and thread angle) showed somewhat stiffer results but with a relatively small influence (less than 10%). From this study, the best screw for use in cancellous bone could be a cortical screw (diameter and pitch) with thread angles similar to a cancellous screw.

<p>Doktorska disertacija razmatra primenu savremenih aditivnih proizvodnih tehnologija u postupku preciznog livenja ortopedskih implantata i njihov uticaj na skraćenje vremena i smanjenje tro&scaron;kova izrade topljivih modela. Konvencionalni postupak preciznog livenja ortopedskih implantata zahteva značajno vreme i tro&scaron;kove za izradu kalupa za topljive modele. U disertaciji je razvijena metoda za &bdquo;brzo precizno livenje&ldquo; kojom se elimini&scaron;e potreba za izradom kalupa za topljive modele ortopedskih implantata. Potrebno je utvrditi da li se pomoću predložene metode &bdquo;brzog preciznog livenja&ldquo; koja predstavlja integraciju aditivnih proizvodnih tehnologija i reverznog inženjerstva sa konvencionalnim preciznim livenjem, može dati značajniji doprinos daljem razvoju u oblasti izrade prilagođenih ortopedskih implantata.</p> / <p>The doctoral thesis discusses the application of modern additive manufacturing technologies in investment casting of orthopaedic implants and their impact on time and cost savings in meltable wax models development. The conventional procedure of investment casting of orthopaedic implants demands considerable time and costs when developing moulds for meltable wax models. The thesis shows a method of &ldquo;rapid investment casting&rdquo; developed to avoid the making the moulds for meltable wax models of orthopaedic implants. It is necessary to establish whether the proposed method of &ldquo;rapid investment casting&rdquo;, which integrates additive manufacturing technologies and reverse engineering with conventional investment casting, may give a significant contribution to further development of manufacturing of customized orthopaedic implants</p>

Este estudo teve como objetivos avaliar os possíveis efeitos da utilização do aparelho propulsor mandibular removível (APM), sobre o crescimento da mandíbula e tipos de fibras nos músculos masseter superficial, pterigóideo lateral e digástrico em ratas. Vinte e sete ratas isogênicas (Fisher 344) foram divididas em três grupos randomizados: dois controles e um experimental, que utilizou o APM removível por 40 dias não consecutivos. Foram feitas reações histoquímicas para avaliar a distribuição dos tipos de fibras nos músculos mastigatórios. A mandíbula de cada animal foi dissecada e foram realizadas medições lineares da mesma. Não houve diferença estatisticamente significante entre os grupos quanto ao crescimento mandibular, e apenas masseter superficial anterior teve alterações, com aumento no número de fibras rápidas (tipo IIB). Em ratos, este modelo de APM, não estimulou aumento de crescimento mandibular e, somente o músculo masseter superficial sofreu alterações significativas quanto à distribuição dos tipos de fibras. / The aim of this study was to evaluate the possibles effects of removeble mandibular propulsive appliance (MPA) on mandibular growth and fiber types of superficial masseter, lateral pyterigoid and digastric muscles. Twenty seven isogenics rats (Fisher 344) were divided into three groups: two controls and one experimental that used the MPA during 40 days. Histochemical analyses was used to evaluate fiber type of masticatory muscles. The jaw of each animal was dissected and measurment was done. There was no signifcant difference on mandibular growth between the groups. Only the anterior portion of superficial masseter had an incresead of rapids fibers (IIB type). These results suggest that this MPA on a rat model, is not efficient to produce any alterations on mandibular growth and just on superficial masseter had significant alterations on muscles fibers types.

Es wird vielfach postuliert, dass Erwartungen Bedeutung für den Verlauf und die Ergebnisse einer medizinischen Rehabilitationsmaßnahme haben (vgl. Deck, 1999; Deck, Zimmermann, Kohlmann & Raspe, 1998b; Faller, Vogel & Bosch, 2000; Hafen, Bengel, Jastrebow & Nübling, 2000; Kühn, Pannicke, Mohs & Schneider, 2001). Im ersten Teil der Arbeit wird diese Thematik aus einer gesundheitspsychologischen Perspektive untersucht. Die sozial-kognitive Theorie von Bandura (1997) wird gewählt, in der Erwartungen wie Ergebnis- und Selbstwirksamkeitserwartungen als zentrale Prädiktoren von gesundheitlichen Ergebnissen angesehen werden. Diese Theorie vermag den Einfluss von Erwartungen auf Gesundheitsverhalten und den Gesundheitszustand zu erklären und zugleich auch die Bildung von Erwartungen zu beschreiben. Auch wenn Ergebniserwartungen die Behandlungsergebnisse vorhersagen, können Diskrepanzen zwischen den anfänglichen Erwartungen der Patienten und ihren Behandlungsergebnissen vorliegen. Aus einer Selbstregulationsperspektive wird angenommen, dass unerwartet schlechte Behandlungsergebnisse möglicherweise negative emotionale und motivationale Folgen haben, die sich auf den weiteren Rehabilitationsprozess auswirken. Zur Erklärung dieser Effekte wird im zweiten Teil der Arbeit ein Modell vorgestellt, das die zentralen Konstrukte und Annahmen der sozial-kognitiven Theory von Bandura (1997; Marlatt & Gordon, 1985), der Selbstregulationstheorie von Carver and Scheier (1998) und der kognitiv-transaktionalen Stresstheorie von Lazarus (1991) vereint. Die Daten der zweiten multizentrischen MSK-QMS Studie zur stationären Rehabilitation nach Hüftgelenkersatz bot als Längsschnittstudie die Möglichkeit, die Fragestellungen beider Teile der Arbeit empirisch zu untersuchen. An dieser Studie nahmen 1065 Rehabilitanden nach Hüftgelenkersatz teil. Die Ergebnisse bestätigen, dass positive Ergebniserwartungen und hohe Selbstwirksamkeitserwartungen gute Behandlungsergebnisse bei Patienten einer stationären Rehabilitationsmaßnahme nach Hüftgelenkersatz vorhersagen. Weitere Analysen zeigen, dass die Erwartungen zu Reha-Beginn durch verschiedene direkte und symbolische Erfahrungen sowie Indikatoren des körperlichen und emotionalen Zustandes beeinflusst werden. Darüber hinaus haben Diskrepanzen zwischen anfänglichen Erwartungen und Behandlungsergebnissen (indirekte) emotionale sowie (direkte und indirekte) motivationale Effekte. Die Befunde werden theoretisch eingebettet und theoriegestützt interpretiert. Praktische Konsequenzen werden abgeleitet. / There is a growing body of literature emphasizing that expectations have effects on the process and outcomes of an inpatient rehabilitation (cp. Deck, 1999; Deck, Zimmermann, Kohlmann & Raspe, 1998b; Faller, Vogel & Bosch, 2000; Hafen, Bengel, Jastrebow & Nübling, 2000; Kühn, Pannicke, Mohs & Schneider, 2001). The first part of the present thesis examines this issue from a health psychology perspective. The social-cognitive theory of Bandura (1997) is chosen that postulates expectations such as outcome expectancies and perceived self-efficacy as main predictors of health outcomes. This theory is able to explain how expectations affect health behaviour and health outcomes and how expectations are formed. Even though outcome expectations predict health outcomes, patients may experience discrepancies between their initial expectations and their later health outcomes. From a self-regulation perspective it is assumed that the experience of unexpected worse health outcomes may have negative emotional and motivational consequences that affect the further process of rehabilitation. To describe these effects a model is introduced in the second part of the thesis that includes main constructs and assumptions of the social-cognitive theory of Bandura (1997; Marlatt & Gordon, 1985), the self-regulation theory of Carver and Scheier (1998) and the cognitiv-transactional theory of Lazarus (1991). In both parts of the thesis research questions are derived that are tested in a longitudinal study (MSK-QMS study). The participants are 1065 adult inpatients who had undergone elective total hip replacement surgery. The results confirm that positive outcome expectations and high perceived self-efficacy predicted better health outcomes in inpatients after hip replacement surgery. Further analyses indicate, that patients'' expectations at admission are affected by several direct and symbolic experiences as well as different indicators of physical and emotional states. Moreover, discrepancies between initial outcome expectations and later health outcomes have (indirect) emotional and (direct and indirect) motivational effects. The results are theory based interpreted. Practical consequences are derived.

This thesis describe methods to improve the interfacial stability of an interpenetrating phase composite (IPC) polyvinylurethanecarbonate), and to increase the hydrophobicity of the polymer phase. The current IPCs introduce covalent bonding between the phases via silanizing agents to enhance the interfacial stability. Incorporation of the silanizing agents was also intended to reduce the IPC’s sensitivity to interfacial hydration, thereby enhancing the IPC’s resistance to degradation during aging. Lysine diisocyanate was used to increase the hydrophobic character in the polyvinylurethanecarbonate resin. The polymer resins were infiltrated into porous CPP blocks with 25 volume% interconnected porosity and polymerized to produce the IPCs. After mechanical testing following a aging study it was found that the silanizing agents contributed to stability of the mechanical properties under aqueous conditions. It was concluded that the mechanical properties and stability were comparable to available biodegradable composites, as well as being biocompatible to a preosteoblast model cell line.

This thesis describe methods to improve the interfacial stability of an interpenetrating phase composite (IPC) polyvinylurethanecarbonate), and to increase the hydrophobicity of the polymer phase. The current IPCs introduce covalent bonding between the phases via silanizing agents to enhance the interfacial stability. Incorporation of the silanizing agents was also intended to reduce the IPC’s sensitivity to interfacial hydration, thereby enhancing the IPC’s resistance to degradation during aging. Lysine diisocyanate was used to increase the hydrophobic character in the polyvinylurethanecarbonate resin. The polymer resins were infiltrated into porous CPP blocks with 25 volume% interconnected porosity and polymerized to produce the IPCs. After mechanical testing following a aging study it was found that the silanizing agents contributed to stability of the mechanical properties under aqueous conditions. It was concluded that the mechanical properties and stability were comparable to available biodegradable composites, as well as being biocompatible to a preosteoblast model cell line.

The aim of this thesis was to investigate some methods for quantitative analysis of bone structure, particularly techniques which might ultimately be applied post-operatively following orthopaedic reconstruction operations. Initially it was decided to explore the efficacy of MRI in quantifying the bone structure at high resolution by comparing high resolution MRI against 'gold standards' such as Scanning Electron Microscopy (SEM) and optical histology. This basic study provided a measure of the distortions in the morphological bone parameters derived from MR images due to susceptibility artefacts and partial volume effects. The study of bone architecture was then extended to a model of advanced renal osteodystrophy in a growing rat. For this study, high-resolution micro computed tomography (microCT) was used and as a result of the high resolution images obtained, three new bone morphological parameters were introduced to characterise the bone structure. The desire to study bone architecture post-operatively in hip replacements led to a preliminary study on ex-vivo sheep acetabulae following total hip replacement, to determine the extent that the bone architecture could be investigated around the acetabulum. The motivation for studying the acetabulum was based on the high occurrence of debonding at the bone / prosthesis interface. This study demonstrated the superior nature of 3D MRI over conventional x-ray radiographs in early quantitation of fibrous membranes located between the host bone and the non-metallic implant and/or the bone cement. The presence of such fibrous membranes is strongly indicative of failure of the prosthesis. When using clinical MRI to image post-operative hip replacement, the image quality is severely affected by the presence of the metallic implant. The head of the prosthesis is shaped like a metal sphere and is located in the acetabular cup. This problem was investigated by performing simulations of MR images in the presence of the field perturbation induced by the presence of a metal sphere, with the effects of slice excitation and frequency encoding incorporated into the simulations. The simulations were compared with experimental data obtained by imaging a phantom comprising a stainless steel ball bearing immersed in agarose gel. The simulations were used to predict the effects of changing imaging parameters that influence artefact size and also to show how current metal artefact reduction techniques such as view angle tilting (VAT) work and to identify their limitations. It was shown that 2D SE and VAT imaging techniques should not be used when metallic prosthesis are present due to extreme slice distortion, whereas 3D MRI provided a method that has no slice distortion, although the effects of using a frequency encoding gradient still remain.

Text in Afrikaans / In this quantitative study emphasis is placed on the role of the nurse as a member of the rehabilitation team. Furthermore, the role of the nurse in patient education as well as the importance of effective patient education during the rehabilitation process after hip replacement surgery is emphasised. Various factors that impacted on the rehabilitation process are highlighted. A structured interview schedule was used to interview a group of 20 respondents. All of the respondents participated voluntarily. Orem's Selfcare Theory was used as a theoretical basis for the study. The researcher determined which information respondents regarded as important to attain functional independence during the rehabilitation process. The data gathered would serve as recommendation for a planned information brochure that could in future be given to patients at their first visit to the surgeon before surgery. The brochure could then be used as a basis for patient education in the course of the rehabilitation process. / Advanced Nursing Sciences / M.A. (Verpleegkunde)