<p>This study is focused on synthesizing Nitinol by additive manufacturing that can provide desirable mechanical properties for orthopedic implants and adding functionally gradient coating that can enhance both safety and biocompatibility for orthopedic implant applications.</p> <p><br></p> <p>The characteristics of additively manufactured Nitinol, by using the direct energy deposition (DED) technique, were experimentally studied. Because of a unique layer-by-layer manufacturing scheme, the microstructure and associated properties (mechanical and thermo-mechanical properties) of the DED Nitinol is different compared to conventionally produced Nitinol. Both the feasibility of manufacturing defect-free microstructure and the precise control of chemical composition were demonstrated. Effects of chemical compositions and post heat-treatment conditions on the phase transformation temperatures of the DED Nitinol were systematically analyzed and compared with those of conventional Nitinol. More precise control of phase transformation temperature from DED Nitinol was possible due to incoherent precipitate formation during aging heat treatment. In a similar way, the mechanical properties of the DED Nitinol were less sensitive to its chemical compositions and post heat-treatment conditions. The feasibility of the precise control of both mechanical and thermo-mechanical properties of the DED Nitinol was demonstrated which can broaden its applications. </p> <p><br></p> <p>The bulk polycrystalline properties of the NiTi phase were studied via molecular dynamics (MD) simulations. Thermo-mechanical properties that are highly sensitive to chemical composition were not precisely predicted from previous reports and studies. In this study, realistic boundary conditions were applied to calculate bulk polycrystalline properties. Thermally driven phase transitions of NiTi between martensite and austenite are simulated with external stresses in both normal and shear directions. It is shown that phase transformation temperatures are affected by applied external stresses, and realistic values compared to experimental data are correctly predicted only when external stresses in both normal and shear directions are similar to the experimentally observed values of 0.05 – 0.1 GPa. The experimentally observed grain orientation and grain boundary thickness were applied to simulation domains for the prediction of the elastic moduli. The elastic moduli of polycrystalline NiTi structure was calculated as 52 GPa which is close to the experimentally reported value of 20-40 GPa while other studies predicted over 85 GPa. </p> <p><br></p> <p>Lastly, pure titanium gradient layers were coated on the Nitinol surface for orthopedic implant applications to eliminate potentially toxic Ni ion release. Using the DED technique, both the core Nitinol and titanium gradient layers were manufactured with high purity and without microstructural defects. An additional biomedical coating of Hydroxyapatite (HA) was deposited on the outer surface using the cold spray technique. The resultant bonding strength was determined to be 26 MPa which exceeded the requirement of the ISO-13779 standard (15 MPa). The <em>in vitro</em> test of the Ni release rate from the entire gradient Nitinol structure was very low, which was comparable to drinking water.</p>

Thesis (Ph. D.)--University of Alabama at Birmingham, 2008. / Additional advisors: Yogesh K. Vohra, Xu Feng, Jack E. Lemons, Timothy M. Wick. Description based on contents viewed July 8, 2009; title from PDF t.p. Includes bibliographical references.

Orientador: William Dias Belangero / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-19T13:05:04Z (GMT). No. of bitstreams: 1 Sawaia_RogerioNaim_D.pdf: 9806060 bytes, checksum: d75ddfca6472ebb85dbfad46a0daa1a4 (MD5) Previous issue date: 2011 / Resumo: INTRODUÇÃO: O tratamento cirúrgico das fraturas intertrocanterianas do fêmur ainda é motivo de estudo e controvérsias. As vantagens da utilização de técnicas minimamente invasivas para essas fraturas já despontam na literatura. O objetivo deste estudo foi avaliar as complicações da técnica minimamente invasiva que utiliza um implante e um instrumental desenvolvidos especificamente (Sistema Minus) para o tratamento dessas fraturas. CASUÍSTICA E MÉTODO: Foram estudados 172 pacientes com fratura intertrocanteriana do fêmur, tratados com o Sistema Minus, dos quais 52 pacientes foram excluídos do estudo por não terem preenchido os critérios de inclusão. No protocolo inicial foram registrados o gênero, a idade, detalhes operatórios como tempo cirúrgico, tempo de uso da fluoroscopia, qualidade da redução e da fixação da fratura. Como parâmetros clínicos foram incluídos a capacidade de marcha, dor, classificação da fratura segundo os critérios de Tronzo e o risco anestésico segundo a classificação de ASA. Dividimos as complicações em dois grupos. As complicações gerais, subdivididas em infecção e mortalidade e as complicações específicas, subdivididas em migração do implante, a perda da redução e a falta de união. Embora a migração do pino deslizante não seja considerada na literatura como uma complicação do DHS (Hrubna e Skotak, 2010)1, no presente estudo ela foi incluída. Cabendo salientar que foi considerada como migração, a impacção lateral da fratura sem a ocorrência de perda de redução. RESULTADOS: O gênero feminino ocorreu em 93 casos e obteve percentual de 77,5%, foi prevalente em relação ao masculino com 27 casos e 22,5%. A idade variou de 52 a 95 anos, com a média de 80,06 anos e desvio padrão de 7,87 anos. A média de idade do gênero masculino foi de 76,19 anos e desvio padrão de 8,321. O gênero feminino obteve a média de 81,18 anos com desvio padrão de 7,407. O tempo cirúrgico médio foi de 39,35 minutos, variando de 25 a 65 minutos. O tempo médio de radioscopia foi 1min7s, variando de 0,6 a 2 minutos e 3s. A redução foi considerada adequada em 92 casos (76,6%), quando obteve-se o alinhamento do eixo de carga, como valgo em 20 casos (16,6%) e como varo em oito casos (6,6%). O somatório médio do TAD (Tip Apex Distance) na incidência Ântero-posterior (AP) foi de 1,19cm, variando de 0,2 a 2,8cm; e no Perfil (P), de 1,14cm, variando de 0,3 a 2,52cm. Dos pacientes, 112 (93,3%) voltaram a andar e a dor pós-operatória em uma escala de 0 a 10, teve a média de 4,44. Dos 120 pacientes, 11 foram classificados como Tronzo I (9,1%), 24 como Tronzo II (20%), 58 como Tronzo III (48,3%), sete Tronzo III variante (5,8%) e 20 Tronzo IV (16,7%). As fraturas instáveis ocorreram em 85 (70,8%) pacientes, os quais 74 (61,6%) tinham idade superior a 75 anos. Já as fraturas estáveis em 35 (29,1%) pacientes, os quais 17 (14,1%) possuíam idade superior a 75 anos. Em relação ao risco anestésico, oito (6,6%) foram classificados como ASA I, 33 (27,5%) ASA II, 74 (61,6%) ASA III e cinco ASA IV (4,16%). Houve um caso de infecção (0,83%). Ocorreram 13 óbitos (10,8%) dentro do primeiro ano de pós-operatório. Desses, um (0,83%) foi classificado como Asa II, cinco (4,16%) como Asa III e sete (5,83%) Asa IV. Dos 85 pacientes com fraturas instáveis, 36 (30%) apresentaram complicações, como perda de redução em 7(5,88%) e migração do pino deslizante em 29 (24,1%). No grupo das 35 fraturas estáveis, as complicações ocorreram em 4 casos (3,33 %), sendo que a perda de redução ocorreu em um caso (0,83%) e a migração em 3 casos (2,5%). No total, a migração ocorreu em 33 casos (27,6%), sendo que desses, todos evoluíram para consolidação. A perda de redução ocorreu em oito (6,7%) e a falta de união, em um caso (0,83%). CONCLUSÃO: Concluímos que a técnica minimamente invasiva, Sistema Minus, é uma técnica segura, que permite a realização da cirurgia com baixa incidência de complicações, quando comparada aos demais métodos existentes / Abstract: INTRODUCTION: The surgical treatment of intertrochanteric fractures is still controversial, resulting in further studies. Many papers have appeared in reference to the advantages of minimal invasive procedures for these fractures. The aim of this study was to evaluate the complications of a minimal invasive procedure using a specific implant and instruments developed for the treatment of intertrochanteric fractures (Minus System). MATERIAL AND METHOD: One hundred and seventy two patients with intertrochanteric fractures of the femur were studied, and submitted to treatment with the Minus System. Fifty two patients were excluded from the study as they did not fulfil all criteria for inclusion. The initial protocol registered gender, age, operative details such as length of operation, length of fluoroscopy use, quality of reduction and fixation of the fracture. The clinical parameters considered included deambulatory ability, pain, Tronzo fracture classification and anesthesia risk according to ASA classification. Complications were divided into two groups: general complications (infection and mortality rate) and specific complications (implant migration, loss of reduction and non-union). Although the migration of a sliding nail has not been considered in the literature as a DHS complication (Hrubna e Skotak, 2010)1 RESULTS: There were 93 feminine cases (77.5%) prevailing on 27 masculine cases (22.5%). Age span was 52 to 95 years, with an average of 80.06 years (standard deviation of 7.87 years). The average age for men was 76.19 years with a standard deviation of 8.321. The average age for women was 81.18 years with a standard deviation of 7.407. The average operative length of time was 39.35 minutes (25 to 65 minutes). The average time of fluoroscopy was 1min 7sec (0.6 to 2min 3sec). Fracture reduction was considered adequate in 92 cases (76.6%), , in the present study it was taken into account. It is important to mention that migration here is the lateral impaction of the fracture without loss of reduction. when alignment with weight-bearing axis was obtained, valgus in 20 cases (16.6%) and varus in eight cases (6.6%). The average Tip Apex Distance (TAD) on an anteroposterior view was 1.19cm (variation of 0.2 to 2.52 cm) and lateral view was 1.14cm (variaton of 0.3 to 2.52cm). One hundred and twelve patients (93,3%) were able to walk with postoperative pain (average of 4.4 on a pain scale of 0 to 10). The classification of the 120 patients is as follows: 11 patients with Tronzo I (9,1%), 24 cases of Tronzo II (20%), 58 Tronzo III (48.3%), seven Tronzo III variant (5.8%) and 20 Tronzo IV (16.7%). Unstable fractures occured in 85 (70.8%) patients, and 74 (61.6%) were over 75 years of age. There were 35 stable fractures (29.1%), with 17 patients (14.1%) over 75 years of age. As to the anesthesia risk eight (6.6%) were classified as ASA I, 33 (27.5%) ASA II, 74 (61.6%) ASA III and five patients as ASA IV (4.16%). There was one case of infection (0.83%). During the first postoperative year there were 13 deaths (10.8%). Of these, one patient (0.83%) had been classified as ASA II, five (4.16%) as ASA III and seven (5.83%) as ASA IV. There were 36 patients (30%) with complications out of 85 patients with unstable fractures, with loss of reduction in seven (5.88%) and migration of the sliding nail in 29 (24.1%). In the group of 35 stable fractures there were complications in four cases (3.3 %), with loss of reduction in one case (0.83%) and migration in three (2.5%). The total number of migrations was 33 (27.5%), but resulted in union in all patients. The loss in reduction occurred in eight patients (6.7%) and non-union in one case (0.83%). CONCLUSION: The minimal invasive procedure, the Minus System, is a safe procedure, that provides adequate surgery with a low incidence of complications, when compared to other existing techniques / Doutorado / Fisiopatologia Cirúrgica / Doutor em Ciências

Dissertation in partial compliance with requirements for the Masters Degree in Technology: Chiropractic, Durban University of Technology, 2010. / The aim of this study was establish if Leander versus Static traction was useful for the treatment of facet syndrome, a common type of mechanical lower back pain seen by chiropractors. Two groups of fifteen participants were chosen on the basis of the inclusion and exclusion criteria. The first objective was to determine if Static linear traction was effective for the treatment of lumbar facet syndrome in terms of subjective and objective findings. The second objective was to determine if Leander traction was effective for the treatment of lumbar facet syndrome in terms of subjective and objective clinical findings. Lastly the third objective was to compare the subjective and objective clinical findings for both groups. Design: A randomised, two group parallel controlled clinical trial was carried out between the two sample groups. Participants had to have had chronic lower back pain (> 3months). Thirty symptomatic volunteer participants between 25 and 55 were randomly divided into two equal groups – group A (Leander traction) received 5 treatments over a 2 week period. Similarly, group B (Static linear traction) also received 5 treatments over a 2 week period. Algometer readings, Numerical Pain Rating Scale (NRS101), Pain Severity Scale (PSS) and Oswestery Disabilty Index (ODI) were used as v assessment tools. Subjective and objective clinical findings were taken on the first and second visits (i.e. 48 hours) prior to treatment and immediately after treatment. Another set of subjective and objective readings were taken one week after the fifth treatment in order to gauge the long term effects of both treatments. No treatment was given on the sixth visit. Pressure tolerance measurements using an algometer were taken at the end ranges of motion in Kemp’s test and spinal extension. Outcome measures: SPSS version 15 (SPSS Inc., Chicago, Illinois, USA) was used for statistical analysis of data. A p value of <0.05 was considered as statistically significant. The two groups were compared at baseline in terms of demographics variables and location using Pearson’s chi square tests and ttests as appropriate. Intra-group comparisons were made between all time points. A significant time effect indicated successful treatment intervention. Inter-group comparisons were achieved using repeated measures ANOVA tests for each outcome measured separately. A significant time group interaction effect indicated a significant treatment effect. Profile plots were used to assess the trend and direction of the treatment effect. Results: The results of the study showed that Leander traction and Static linear traction were both effective for treating chronic lumbar facet syndrome and no statistically significant difference was found between subjective and objective clinical findings between the two groups.

Dissertation submitted in partial compliance with the requirements for the Master’s Degree in Technology: Chiropractic, Durban University of Technology, 2012. / Lateral epicondylalgia (L.E) is a common diagnosis in elbow pathology. The aetiology is poorly understood but it is generally accepted to be as a result of repetitive microtrauma, affecting the proximal end of the extensor carpi radialis brevis tendon. Elbow bracing and exercise modification are often utilised by sufferers in order to reduce symptoms. In addition, there have been multiple treatment regimes used in practice to treat L.E, but none has stood out as being more effective than another. Thus, the aim of this study was to investigate the relative clinical effectiveness of therapeutic exercises alone and in combination with orthotic bracing, in terms of subjective and objective clinical findings. Methods This stratified, quantitative, prospective clinical trial consisted of two equal groups (n=15) diagnosed with L.E. Group One consisted of a strengthening and stretching programme alone, and Group Two consisted of a combination of the same programme and an orthotic brace. The participants performed the programme daily at home for six weeks, and the brace was worn throughout the day for six weeks. Each participant was assessed before, during and after the programme, in terms of subjective and objective clinical data which was then statistically analysed using SPSS version 18. Repeated measures ANOVA testing was also used to compare the outcomes between the groups over the time points. Results Both groups showed significant statistical improvement in terms of all the outcome measures. The groups also showed a clinically significant improvement for all the outcome measures except pressure pain threshold where Group Two showed clinically significant improvement over Group One. v Conclusion The results show that there was negligible benefit when combining an orthotic brace with therapeutic exercises as opposed to performing the therapeutic exercises alone.

Thesis (MMed (Surgical Sciences. Orthopaedic Surgery))--University of Stellenbosch, 2010. / No abstract available

published_or_final_version / Orthopaedics and Traumatology / Master / Master of Philosophy

published_or_final_version / Orthopaedics and Traumatology / Master / Master of Philosophy

Paralelamente à transição demográfica, a prevalência do trauma em idosos tem aumentado de forma significativa nos últimos anos. O trauma, não raras vezes está associado à seqüelas, incapacidades, deficiências e mesmo à diminuição da capacidade funcional, representando um prejuízo na qualidade de vida das vítimas e suas famílias devido à perda da autonomia e independência, tornando–se uma importante questão social , econômica e de saúde. Deste modo, o presente estudo teve como objetivo geral, avaliar a independência funcional de idosos vítimas de fratura, na admissão hospitalar, alta e um mês após o regresso ao domicílio e verificar suas relações com as variáveis sociais e de saúde. Participaram do estudo 34 idosos com idade média de 75,47 anos, hospitalizados na Unidade de Trauma-Geriatria ou Pronto Socorro do Instituto de Ortopedia e Traumatologia da Faculdade de Medicina da USP, vítimas de fratura. Os dados foram coletados pela pesquisadora por meio de entrevistas para a caracterização biodemográfica e pela aplicação da Medida de Independência Funcional (MIF). A aplicação da MIF se deu em três momentos: até 48 horas após a internação, na alta hospitalar e após um mês do regresso do idoso ao domicílio, desta vez por meio de contato telefônico. Da totalidade, 82,4% dos idosos se declararam brancos, 52,9% eram do sexo feminino, apenas 11,8% referiram prática regular de atividade física. Quanto ao trauma: a fratura de fêmur predominou representando 67,6% das fraturas, sendo 53% fraturas transtrocanterianas e 39% do colo de fêmur. A queda no ambiente doméstico foi o principal mecanismo de trauma. O tempo médio de permanência hospitalar foi de 15,47 dias. A modalidade de tratamento empregada foi essencialmente cirúrgica com destaque para o DHS (parafuso dinâmico de quadril) e as artroplastias parciais e totais de quadril. Quanto à independência funcional: houve um aumento considerável nas médias dos valores da MIF motor e total no momento da alta, comparado à admissão; em contrapartida houve uma diminuição dos valores médios da MIF total um mês após regresso ao domicílio. Observou-se que a incapacidade funcional aumentou com a idade e uma significativa associação entre maiores comprometimentos funcionais e maiores dias de internação. A presença contínua de acompanhante constituiu-se em um fator protetor contra o declínio funcional. O hipotireoidismo, a demência e a depressão foram associados à menores scores da MIF motora. O presente estudo aponta ainda para o fato de que a maioria dos idosos voltou para a comunidade com necessidade de alguma forma de assistência para os cuidados pessoais, mobilidade e locomoção, acentuando assim a importância do papel da família / With the demographic transition, the prevalence of trauma in aged have increased considerably at the ultimate years. The trauma, is often related to , injuries, impairments, deficiencies , and also to the decrease of the functional capacity, representing a damage in the victims’ quality of life and their families due to the loss of the autonomy and independence, becoming an important social, economic and health question. Thus this study had as main objective to evaluate the functional independence of the aged victims of fractures, at admission, discharge and after one month from the regress to home and verify the relation with social and health questions. 34 aged about 75,47 years old took part of the study, they were inpatient of the Trauma- Geriatric or Emergency room of the Orthopedic and Traumatologyc Institute of the University of São Paulo’s Medicine School, all aged were victims of fracture. Data were collected by the researcher by means of and interview intending a biodemographic characterization and by the application of the Functional Independence Measure (FIM). The application of the FIM occurred in three times: until 48 hours after the admission, at the discharge and after one month from the regress to home this time by a telephone contact.82,4% of the aged declared theirselves as Caucasian, 52,9% were female, only 11,8% refered regular practice of physical activity. Related to the trauma: the femur fracture prevailed representing 67,6% of the fractures, 53% were transtrochanteric fractures and 39% were femur neck fractures. The fall at home was the main trauma mechanism. Mean time of hospitalization was 15,47 days. The modality of treatment used was essentially surgical, it was remarkable the use of the DHS (Dynamic Hip Screw) and the total or parcial hip artroplasty. Related to the functional independence: there was a remarkable increase of the motor and total FIM scores at the discharge compared to the admission, on the other hand, there was a decrease of the total FIM one month after the regress to home. It was noticed that the functional impairment increased with the age and also an expressive relation between the functional impairment and a long time of hospitalization. The presence of a companion was a protector factor against the functional impairment. The hipotireoidism, the demencia and the depression were associated to lower scores of motor FIM. This study show us that the majority of the aged returned to the community demanding some modality of assistance for self-care, mobility and locomotion, emphasizing the importance of the family care

"Modeling and Simulation of Oxidative Degradation of UHMWPE is studied in details.UHMWPE is commonly used in knee replacements or total hip replacements."