• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 75
  • 42
  • 6
  • 5
  • 5
  • 4
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 165
  • 28
  • 24
  • 24
  • 22
  • 22
  • 22
  • 21
  • 18
  • 18
  • 17
  • 16
  • 15
  • 15
  • 14
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Correntes russa e aussie na recuperação do músculo tibial cranial após neurorrafia látero-terminal em ratos / Russian and aussie current on the recovery of cranial tibial muscle after endo-to-side neurorrhaphy in rats

Simionato, Luis Henrique [UNESP] 03 March 2017 (has links)
Submitted by LUIS HENRIQUE SIMIONATO null (ssimionato@terra.com.br) on 2017-04-10T19:23:25Z No. of bitstreams: 1 Tese Final Luis H Simionato.pdf: 3223169 bytes, checksum: 04fabe07df60f36e93b175e558c5209c (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-04-17T18:14:33Z (GMT) No. of bitstreams: 1 simionato_lh_dr_bot.pdf: 3223169 bytes, checksum: 04fabe07df60f36e93b175e558c5209c (MD5) / Made available in DSpace on 2017-04-17T18:14:33Z (GMT). No. of bitstreams: 1 simionato_lh_dr_bot.pdf: 3223169 bytes, checksum: 04fabe07df60f36e93b175e558c5209c (MD5) Previous issue date: 2017-03-03 / Introdução: Lesões de nervos periféricos podem levar uma perda funcional elevada ao paciente. Devido a este fator, muitas pesquisas buscam propor técnicas para melhorar a funcionalidade de um músculo reinervado. A neurorrafia látero-terminal (NLT), sem lesão no nervo doador, trouxe grande contribuição, pois a partir desta descoberta, qualquer nervo pode ser utilizado como nervo doador sem prejuízos para este ou para as estruturas por ele inervadas. Entretanto, após uma neurorrafia, o tempo para a regeneração axonal determinará atrofia das fibras musculares. Assim, a estimulação elétrica preveniria este fator negativo. Objetivo: Esta pesquisa teve como objetivo estudar a eficiência da estimulação elétrica na regeneração do músculo tibial cranial após secção e neurorrafia látero-terminal do coto distal do nervo fibular comum à face lateral do nervo tibial. Métodos: Foram utilizados 120 ratos Wistar machos (Rattus norvergicus), eletroestimulados com corrente russa e aussie, após neurorrafia látero-terminal em dois períodos diferentes: 45 e 90 dias, distribuidos em 11 grupos: Grupo Controle Inicial (GCI); Grupo Neurorrafia Látero-Terminal (GNLT45 e GNLT 90) ; Grupo Neurorrafia Látero-Terminal com Estimulação Aussie (GEA45 e GEA90) ; Grupo Neurorrafia Látero-Terminal Estimulação Russa (GER45 e GER90); Grupo Desnervado (GD45 e GD90) ; Grupo Controle Final (GCF45 e GCF90).Foram realizadas análises morfométricas dos tecidos musculares e funcionais dos ratos de todos os 11 grupos, comparando a resposta da regeneração trófica do tecido muscular. Resultados e Discussão: Os resultados referentes às médias dos valores da área das fibras do MTC dos grupos eletroestimulados GEA45 (2202,64µm2), GER45 (2198,91µm2), GEA90 (2759,94µm2) e GER90 (2777,28µm2), sempre foram maiores que os dos grupos controle cirúrgico GNLT45 (1778,27µm2) e GNLT 90 (1904,67µm2); repetindo a mesma relação de resultado em relação ao do diâmetro menor, GEA45(44,14µm), GER45(43,71µm), GEA90(51,06µm) e GER90 (51,31µm), maiores do que dos grupos controle cirúrgico GNLT45 (30,43µm) e GNLT 90 (142,38µm). Em relação à densidade de tecido conjuntivo, os resultados encontrados foram: GEA45 (7,92%), GER45 (8,84%), GEA90 (9,66%) e GER90 (7,00%). Os resultados referentes ao Teste de Força de Contração Máxima nos grupos eletroestimulados GEA45, GER45, GEA90 e GER90 apresentaram resultados superiores ao grupo que somente realizou a neurorrafia. A avaliação da intensidade da pegada entre os grupos com períodos de diferentes tempos de eletroestimulação, 45 e 90 dias, demonstrou uma influência positiva no período maior e o grupo 90, com média de 21,94 de intensidade de pressão da pegada. Conclusão: Após a comparação entre os grupos com períodos de eletroestimulção diferentes 45 e 90 dias, entre grupos de mesmo período de eletroestimulação não houve diferença significativa, mas entre os grupos com períodos diferentes, 45 e 90 dias, ocorreu uma influência positiva no período maior, o que permitiu constatar que existe uma relação direta na melhora das características morfológicas e funcionais do tecido muscular pós NLT com o aumento do período de eletroestimulação. / Introduction: Peripheral nerve injury can lead to a high functional loss to the patient. Due to this factor, many researches seek to propose techniques to improve the functionality of a reinnervated muscle. The End-to-Side Neurorrhaphy (ESN), without injury to the donor nerve, brought great contribution, since from this discovery, any nerve can be used as donor nerve without damages to themselves or to the structures innervated by it. However, after a neurorrhaphy, the time for axonal regeneration will determine atrophy of the muscle fibers. Electrical stimulation would prevent this negative factor. Purpose: This research aimed to study the efficiency of electrical stimulation in the regeneration of the cranial tibial muscle after section and end-to-side neurorrhaphy of the distal stump of the peroneal nerve to the lateral aspect of the tibial nerve. Methods: A total of 120 male Wistar rats (Rattus norvergicus) were used, electrostimulated with Russian and Aussie current, after End-to-Side Neurorrhaphy in two different periods, 45 and 90 days, divided into 11 groups: Initial Control Group (ICG); End-to-Side Neurorrhaphy Group (EESNG45 and EESNG90); End-to-Side Neurorrhaphy with Aussie Stimulation Group (ASG45 and ASG90); End-to-Side Neurorrhaphy with Russian Stimulation (RSG45 and RSG90); Unnerved Group (UG45 and UG90); Final Control Group (FCG45 and FCG90). Morphometric analyzes of the muscular and functional tissues of the rats of all 11 groups were performed, comparing the trophic regeneration response of muscle tissue. Results and Discussion: The results of the mean values of the cranial tibial muscle fiber area of the electrostimulated groups, ASG45 (2202.64μm2), RSG45 (2198.91μm2), ASG90 (2759.94μm2) and RSG90 (2777.28μm2) were always higher than the surgical control group EESNG45 (1778.27 μm2) and EESNG90 (1904.67 μm2), repeating the same result ratio with respect to the smaller diameter, ASG45 (44.14μm), RSG45 (43.71μm), ASG90 (51.06μm) and RSG90 (51.31μm), higher than the EESNG45 surgical control groups (30.43μm) and EESNG90 (142.38μm). In relation to the density of connective tissue the results were: ASG45 (7.92%), RSG45 (8.84%), ASG90 (9.665%) and RSG90 (7.00%). The results for the Maximum Contraction Strength Test the ASG45, RSG45, ASG90 and RSG90 electro-stimulated groups presented higher results than the group that only performed neurorrhaphy. The evaluation of the intensity of the footprint between the groups with different periods of electrostimulation times, 45 and 90 days, had a positive influence in the longer period, group 90, with a mean of 21.94 of pressure intensity of the footprint. Conclusion: The comparison between groups with different periods of electrostimulation, 45 and 90 days, showed that was no significant difference between groups of the same electrostimulation period, but between the groups with different periods, 45 and 90 days, a positive influence occurred in the longer period, thus confirming that is a direct relationship in the improvement of the morphological and functional characteristics of muscle tissue after ESN with the increase of the electrostimulation period.
72

Estudos moleculares em famílias com defeitos de membros / Molecular studies in families with limb defects

Renata Soares Thiele de Aguiar 25 April 2011 (has links)
No presente trabalho foram desenvolvidos estudos genético-moleculares em três famílias com três síndromes distintas de defeitos dos membros. A ectrodactilia ou SHFM (split-hand/split-foot malformation) é uma malformação congênita da extremidade dos membros caracterizada por fenda mediana profunda das mãos e/ou pés devido à ausência dos raios centrais. A hemimelia tibial é um defeito caracterizado por hipoplasia, aplasia ou agenesia de tíbia, em que a fíbula permanece intacta. A síndrome da hemimelia tibial associada à ectrodactilia é uma condição rara de herança dominante. Em uma publicação do nosso grupo foi mapeado um novo loco (SHFLD3 OMIM #612576) de hemimelia tibial associada à ectrodactilia (Lezirovitz e col. 2008. Am J Hum Genet 123:625-31) na região 17q13.1-17p13.3 em uma família com nove indivíduos afetados por essa síndrome. Nesse estudo foram sequenciados seis genes localizados na região candidata, mas nenhuma mutação patogênica foi encontrada. Em pesquisa colaborativa com grupo no exterior identificou-se uma duplicação de cerca de 114 Kb nessa região cromossômica. Ela estava presente em todos os indivíduos afetados e por meio de PCR de longo alcance e seqüenciamento foi possível identificar os pontos de quebra da duplicação. Os resultados indicaram que essa é a provável causa da síndrome na família. A agenesia/hipoplasia fibular é um defeito que ocorre ao longo do desenvolvimento e extensão da fíbula. Ela é encontrada isolada ou associada com outros sinais clínicos como malformações em membros superiores, como a ectrodactilia, e defeitos na ulna e fêmur. Em uma família em que segrega uma nova síndrome, uma forma de agenesia ou hipoplasia fibular associada à ectrodactilia de aparente herança autossômica dominante (Santos e col. 2008. Am J Med Genet A. 146A: 3126-31) foram realizados estudos de mapeamento por meio de marcadores de microssatélites e sequenciamento dos genes nas regiões candidatas. Após a exclusão de ligação com algumas regiões já conhecidas associadas a defeitos de membros, foram sequenciados alguns genes candidatos selecionados a partir da literatura sobre defeitos de membros (SHH, ZRS, WNT7a, WNT10b, GREM1). Dado que mutações não foram identificadas nesses genes, foi realizada a varredura genômica com o kit Affymetrix GeneChip® Human Mapping 50K Array. Foi observado que em quatro cromossomos (5, 6, 10 e 11) não foi possível a exclusão completa de ligação. Nesses cromossomos foram utilizados marcadores de microssatélites próximos às regiões que apresentaram lod score sugestivo de ligação. As análises dos cromossomos 6 e 10 não confirmaram evidências de ligação. No cromossomo 5 e no cromossomo 11 não foi possível a exclusão completa de ligação. A terceira família é composta por três indivíduos afetados por um quadro variável de defeitos de membros, entre eles, polissindactilia, sindactilia, camptodactilia e defeitos ungueais. O heredograma sugere um padrão de herança do defeito compatível com herança autossômica dominante e penetrância completa. Realizaram-se estudos preliminares de ligação com microssatélites próximos as regiões cromossômicas já conhecidas associadas a malformações de membros. Na região candidata 17p13.1-17p13.3 não foi possível a exclusão completa de ligação, já que os lod scores chegaram a mostrar valores positivos e sugestivos. Também foram sequenciados alguns genes candidatos (SHH, ZRS, WNT7a, WNT10b, GREM1). Dado que mutações não foram identificadas, foi realizada a varredura genômica com o kit Affymetrix GeneChip® Human Mapping 50K Array. A análise dos SNPs dos cromossomos 19, 20 e 21 permitiu a exclusão completa de ligação com esses cromossomos. Já em relação aos demais cromossomos, não se pode excluir completamente a ligação, já que vários deles apresentaram lod scores muito próximos do lod máximo possível calculado para a família. A dificuldade decorre do fato da família ser pequena e possuir somente duas gerações com indivíduos afetados. As regiões mais interessantes para aprofundar a investigação seriam as do cromossomo 17, pois houve sugestão de ligação também na análise de microssatélites. O gene YWHAE no cromossomo 17 foi sequenciado por se mostrar um bom candidato. No entanto, nenhuma mutação foi encontrada. / Here we report our genetic and molecular studies performed on three different families affected by three different syndromes with limb defects. Ectrodactyly or SHFM (Split Hand/Foot Malformation) is a congenital limb malformation characterized by median cleft of hands or feet (absence of the central rays). Tibial Hemimelia is a malformation characterized by tibial hypoplasia, aplasia or agenesis without fibular involvement. Ectrodactyly associated with tibial hemimelia is a rare autosomal dominant condition. In a previous publication of our team, we reported the mapping of a novel locus (SHFLD3 OMIM #612576) for ectrodactyly associated with tibial hemimelia (Lezirovitz e col. 2008. Am J Hum Genet 123:625-31) to chromosome region 17q13.1-17p13.3 in a large family with nine affected individuals. Six genes in the candidate region were sequenced, but no pathogenic mutation was found. In a collaborative study with another Center, a 114 Kb duplication, detected in all affected individuals, was found in this same region. Duplication breakpoints were identified after long range PCR and sequencing. Our results indicated indicating that this is the causative mutation in the family. Fibular agenesis/hypoplasia is a fibular developmental defect, occurring either as an isolated defect or associated with other clinical signs, such as hand ectrodactyly, ulnar and femoral defects. Mapping studies with microsatellite markers were performed on a family with some affected individuals presenting fibular agenesis or fibular hypoplasia associated with ectrodactyly, a novel defect that segregates with a possible autosomal dominant mode of inheritance (Santos e col. 2008. Am J Med Genet A. 146A:3126-31). Linkage with markers mapped to some well known chromosome regions related with limb malformations was excluded. Some candidates genes possibly related to limb malformations were selected from the literature for sequencing (SHH, ZRS, WNT7a, WNT10b, GREM1). Since no mutation was found, we proceeded to genomic scanning with Affymetrix GeneChip Human Mapping 50k Array. Linkage with markers from four chromosomes (5, 6, 10 and 11) could not be completely excluded. Microsatellite markers were used to confirm linkage to regions presenting the higher lod scores and markers on chromosomes 6 and 10 did not confirm linkage. Analyses with markers on chromosomes 5 and 11 (in which there are no good candidate genes reported in the literature) were inconclusive and linkage could not be completely ruled out. There are three affected individuals in the third family here reported, each one of them presenting with a different set of distal limb defects (such as syndactyly, polysyndactyly, camptodactyly, or nail malformation); the defect is transmitted with an autosomal dominant mode and complete penetrance. Linkage studies with microsatellite markers close to well-known limb malformation related regions were performed. Linkage with region 17p13.1-17p.13.3 could not be ruled out since some of the lod scores were positive and suggestive. Some candidates genes have been selected for sequencing (SHH, ZRS, WNT7a, WNT10b, GREM1). Since no mutation was found, genomic scanning was performed with the Afflymetrix GeneChip Human Mapping 50k Array. SNP analysis of chromosomes 19, 20 and 21 allowed us to rule out linkage completely. However, linkage could not be excluded for some regions on other chromosomes, since their lod scores were close to the maximum possible score estimated for this small-sized family. The most interesting regions are located in chromosome 17, in which the gene YWHAE, which seemed to be a good candidate, was sequenced, but no mutation was found.
73

Comparação de protocolos de eletroestimulação do nervo tibial para tratamento da bexiga hiperativa: ensaio clínico randomizado cego / Comparison of protocols tibial nerve electrostimulation for treatment of overactive bladder: a randomized blinded clinical trial

Munick Linhares Pierre 12 May 2015 (has links)
INTRODUÇÃO: No tratamento da síndrome bexiga hiperativa (SBH) a eletroestimulação do nervo tibial é uma terapêutica conservadora, eficaz, de baixo custo, de boa aderência pelas pacientes e com resultados satisfatórios. Não há consenso na literatura quanto à periodicidade e ao número de pontos para aplicação da técnica. OBJETIVO: Comparar a eficácia de protocolos de eletroestimulação do nervo tibial para tratamento fisioterapêutico da SBH não neurogênica. MÉTODOS: ensaio clínico randomizado cego com 138 mulheres portadoras da SBH há seis meses ou mais, randomizadas em cinco grupos: eletrodos posicionados em uma perna com sessões de uma ou duas vezes por semana, eletrodos posicionados em duas pernas com sessões de uma ou duas vezes por semana e um grupo controle. Foram utilizados os instrumentos: King\'s Health Questionnaire (KHQ), International Consultation on Incontinence Questionnarie - Short Form, Overactive Bladder Questionnaire (OAB-V8), Diário Miccional e uma Ficha de Avaliação Contínua. RESULTADOS: A média de idade foi de 61(±9), sendo que 91% estavam na menopausa. Na frequência urinária o protocolo de duas sessões foi melhor do que o de uma vez por semana (p=0,026). Para o sintoma de urgência e incontinência uma vez por semana teve melhor resultado (p=0,046 e p=0,0001, respectivamente). No sintoma de noctúria a aplicação nas duas pernas foi mais eficaz (p=0,005). Em relação a qualidade de vida, apenas o domínio \'limitações físicas\' do KHQ apresentou diferença significativa (p=0,0411). Conclusão: É importante identificar o sintoma mais frequente da SBH para individualizar a conduta fisioterapêutica. A forma de aplicação dos eletrodos e a frequência do tratamento devem ser modificadas de acordo com as necessidades de cada paciente / BACKGROUND: In the treatment of overactive bladder (OAB) electrical stimulation of the tibial nerve is a conservative therapeutically effective, low cost, good adherence of the patients with satisfactory results. There is no consensus in the literature regarding the periodicity and the number of points for the technical implementation. PURPOSE: To compare the efficacy of electrical stimulation of the tibial nerve protocols to physical therapy for neurogenic OAB not. METHODS: blind randomized clinical trial in 138 women suffering from OAB six months or more randomized into five groups: electrodes positioned on one leg sessions with one or two times per week, electrodes positioned on both legs sessions once or twice per week and a control group. The instruments used were: King\'s Health Questionnaire (KHQ), International Consultation on Incontinence Questionnaire - Short Form, Overactive Bladder Questionnaire (OAB-V8), Voiding Diary and a Continuous Assessment Form. RESULTS: The mean age was 61 ( ± 9), and 91% were in the menopause. In the urination two protocol sessions was better than the once a week (p = 0.026). For the symptom of urgency and incontinence once a week had better result (p = 0.046 and p = 0.0001, respectively). In the application nocturia symptom in both legs was more effective (p = 0.005). In relation to quality of life, only the domain \'physical limitations\' KHQ showed a significant difference (p = 0.0411). Conclusion: It is important to identify the most common symptom of OAB to individualize the practice of physical therapy. The form of application of the electrodes and the frequency of treatment should be modified according to the needs of each patient
74

Estudo biomecânico de tração (ex-vivo) em osteotomia da tuberosidade tibial de cães estabilizada com placa fixa por \"garfo\" ou parafuso / Biomechanical study of traction (ex-vivo) on the tibial tuberosity osteotomy in dogs stabilized with plates fixed by \"fork\" or screws

Kelly Cristiane Ito 09 November 2012 (has links)
Avanço da tuberosidade tibial (ATT) é uma das técnicas para tratamento da ruptura do ligamento cruzado em cães desenvolvida por Montavon, Damur e Tepic (2002). O sucesso da técnica em reduzir ou eliminar as forças de deslocamento cranial da tíbia em joelhos com ruptura do ligamento cruzado cranial tem sido documentado em estudos experimentais e clínicos. No período pós-operatório a técnica, a falha do implante é relatada em 1 a 5% dos membros pélvicos operados. Este número foi atribuído a erro de técnica ou desenho inicial do implante que foi considerado insuficiente. Com objetivo de comparar a resistência biomecânica entre duas diferentes placas de ATT e minimizar a incidência de falhas de implante, foram realizados ensaios biomecânicos em 10 pares de membros pélvicos de cadáveres cães, no membro pélvico direito placa fixa por garfo e no membro pélvico esquerdo placa fixa por parafusos. Os ensaios foram realizados utilizando-se máquina universal de ensaios mecânicos Kratos® modelo 5002, dotada de célula de carga de 3000N com uma velocidade de ensaio de 20 mm/min. O parâmetro força e os gráficos gerados foram gravados por meio de sistema de aquisição analógica TRACOMP-W95 (TRCV61285). A média da carga máxima até a falha foi de 128,70 Kg/F (mínimo 104,55 Kg/F e máximo 151,80 Kg/F) e de 141,99 Kg/F (mínimo 111,60 Kg/F e máximo 169,65 Kg/F) no grupo utilizando \"garfo\" e parafusos respectivamente. O desvio padrão dos grupos \"garfo\" e parafuso foi baixo, 12,99 e 17,21 respectivamente. Foi encontrada diferença significativa (p = 0,0309) entre as médias dos grupos. / Tibial tuberosity advancement (TTA) is one of the techniques for treatment of cruciate ligament rupture in dogs developed by Montavon, Damur and Tepic (2002). The success of the technique in reducing or eliminating the forces of cranial tibial displacement in knees with ruptured cranial cruciate ligament as been documented in experimental and clinical studies. In the post-operative technique, implant failure is reported in 1-5% of hindlimbs operated. This number was attributed to technical error or the initial design of the implant that was considered insufficient. To compare the biomechanical strength between two different plates ATT and minimize the incidence of implant failures, biomechanical tests were performed on 10 pairs of hindlimbs cadaver dogs, the right hindlimb fixed plate and a fork in the left pelvic limbplate fixed by screws. As says were performed using a universal mechanical testing Kratos ® model 5002, equipped with a load cell of 3000N with a test speed of 20 mm / min. The strength parameter and graphs generated were recorded via analog acquisition system TRACOMP-W95 (TRCV61285). The mean load to failure was 128.70 kg/F (minimum 104.55 Kg and maximum 151.80 Kg/F) and 141.99 Kg/F (minimum 111.60 Kg/F and maximum 169.65 Kg/F) in the group using \"fork\" and screws respectively. The standard deviation of the groups \"fork\" and bolt was low, 12.99 and 17.21 respectively. Significant difference (p = 0.0309) between the means of the groups.
75

Einfluss der intraindividuellen Slopedifferenz auf die femorale Rotation bei Patienten mit lateraler Patellainstabilität / The influence of intra-individual tibial slope asymmetry on femoral rotation in patients with lateral patellar instability

Gehle, Annika Karola 06 October 2020 (has links)
No description available.
76

Oxford Rig Simulation for Analysis of the Effect of Posterior Tibial Slope Changes and Variable Ligament Stiffness on Knee Biomechanics

Geers, Katherine 27 October 2022 (has links)
No description available.
77

Developing Models to Study Relationships between Tibial Acceleration Measures and Lower Extremity Musculoskeletal Disorder Symptoms Experienced by Distribution Center Workers

Dutt, Mohini 09 June 2016 (has links)
No description available.
78

The development and evaluation of a management plan for musculoskeletal injuries in British army recruits : a series of exploratory trials on medial tibial stress syndrome

Sharma, Jagannath January 2013 (has links)
This thesis is the culmination of a series of studies designed to improve the management of musculoskeletal (MSK) injury in an infantry training centre (ITC Catterick, UK). The overall aim of this thesis is to develop and evaluate a management strategy for MSK injury during Combat Infantryman’s Courses (CIC) training. Included is an epidemiological study of MSK injuries in the British Army (Study1), a risk factor model for MTSS (Study 2) and two randomised controlled trials (RCTs) in which the effects of prevention (Study 3) and rehabilitation interventions (Study 4) were examined. The aim of Study 1 was to quantify incidence, type and impact of the MSK injuries during military CIC training (26 weeks). Over a two year period (April 2006 -March 2008), 6608 British infantry CIC trainees completed an informed consent form to take part in this study. A prospective epidemiological study was conducted. Data for the injuries were reported according to: onset, anatomical location, diagnosis and regiment-specific incidence, week and months, impact and occupational outcome. It was clearly demonstrated that MSK injuries are a substantial burden to the British Army. Injury rate was 48.65% and overuse injury was significantly higher than acute and recurrence. Most overuse injuries occurred in the lower limb (82.34%) and were more frequent (p <0.01) in the first phase of training (Weeks 0-13). One third of the recruits (33%) were discharged prior to completion of training. A further 15% (n=991) were removed from training for further rehabilitation. Rehabilitation time ranged from 21 to 168 days and 12% of total training time was lost due to injury (equivalent to 155,403 days of training). Owing to its high severity index, medial tibial stress syndrome (MTSS) is argued to be the most impactful of these injuries despite only being second most frequent. Implications for practice and research (Study 1): MSK injuries are a significant burden to the British Army and strategies to improve prevention and treatment need to be explored. An initial focus on MTSS is warranted. In order to develop interventions for Studies 3 and 4 it is necessary to identify those risk factors for developing MTSS. The aim of Study 2 was to determine prospectively whether gait biomechanics and/or lifestyle factors can identify those at risk of developing MTSS. Again, British Infantry male recruits (n = 468) were selected for the study. Based on a review of the literature of known risk factors for MSK injury, plantar pressure variables, lifestyle factors comprising smoking habits and aerobic fitness as measured by a 1.5 mile timed-run were collected on the first day of training. A logistic regression model for membership of the MTSS and non-MTSS groups showed that an imbalance in foot pressure (heel rotation = pressure on the medial heel minus pressure on the lateral heel) was the primary risk factor for MTSS. Low aerobic fitness and smoking habit were also important, but were additive risk factors for MTSS. The logistic regression model combining all three risk factors was capable of predicting 96.9% of the non-injured group and 67.5% of the MTSS group with an overall accuracy of 87.7%. Implications for practice and research (Study 2): Foot pronation, as measure by heel rotation, is a primary risk factor for MTSS. Previous studies have shown that gait retraining can change risk factors for injury. The aim of Study 3 was to examine the effectiveness of gait retraining on reducing risk factors associated with MTSS and on reducing the incidence of MTSS during the subsequent 26 week training period. British Infantry recruits (n = 450) volunteered for the study and baseline plantar pressure variables were recorded on the first day of training. Based on the findings of Study 2, those with abnormal foot pronation at baseline (n = 134, age 20.1 ± 2.03 years; height 167 ±1.4 cm; body mass 67 ± 2.4 kg) were randomly allocated to an intervention (n = 83) or control group (n = 83). The intervention group undertook a gait retraining program which included targeted exercises three times a week and biofeedback on risk factors once per week. Both groups continued with the CIC training concurrently. Injury diagnoses over the 26 week training regimen were made by physicians who were blinded to the study. Post-measures of plantar pressure were recorded at 26 weeks. There was a significant reduction in the pronation (p <0.001) and overall difference survival function between MTSS and non-MTSS (Log rank test X2 = 6.12, p = 0.013). The absolute risk reduction was 60% in the intervention group. Implications for practice and research (Study 3): Gait retraining can reduce risk factors and incidence of MTSS injury. Based on such positive findings for the prevention of MTSS in Study 3, it was hypothesised that gait retraining may also have potential for the rehabilitation of MTSS. The aim of Study 4 was to examine the effectiveness of a gait retraining on plantar pressure variables, pain intensity and time spent in rehabilitation due to MTSS. Recruits diagnosed with MTSS but not responding to current treatment were eligible for this study (n = 66, age 20.85 ± 2.03 years; height 167 ±1.4 cm; body mass 67 ± 2.4 kg). The participants were randomly allocated to an intervention (n = 32) or control group (n = 34). In order to overcome the debilitating pain suffered by MTSS patients during exercise, the intervention group received a corticosteroid injection prior to the gait retraining programme. The control group continued with the current rehabilitation programme. There were significant improvements in terms of time to reach peak heel rotation (p<0.001), pain intensity (p<0.001) and positive occupational outcome in the intervention group (p<0.019). Implications for practice and research (Study 4): A combined corticosteroid-exercise intervention is beneficial in normalising plantar pressure, reducing rehabilitation times, pain intensity and occupational outcome of MTSS.
79

Kinematics and fixation of total knee arthroplasties : a clinical, radiographic, scintimetric, and roentgen stereophotogrammetric evaluation

Nilsson, Kjell G. January 1992 (has links)
Aseptic loosening of the tibial component is an important cause of failure after total knee arthroplasty. Bone destruction often claimed to be caused by the cement makes the revision difficult. In order to treat younger patients, uncemented fixation has been introduced, but the etiology to loosening is multifactorial and only partly known. Early detection of implant migration facilitates research in this field but is difficult using conventional techniques. In this study modified versions of roentgen stereophotogrammetric analysis (RSA) were developed to obtain accurate and standardized evaluations facilitating comparison between prosthetic designs. The method was used to record the efficacy of cemented and uncemented fixation of different designs of the tibial component, to determine the accuracy of scintimetry in the detection of early aseptic loosening, and to analyse the in vivo kinematics of knee arthroplasties with different design and stability between the joint surfaces. Forty-three arthroplasties with comparatively high inherent stability of the joint surfaces were randomized to cemented or uncemented fixation of the tibial component. In all groups micromovements were rather large, but with no differences between the cemented and uncemented components. The preoperative diagnosis (arthrosis OA, n=25; rheumatoid arthritis RA, n=18) did not influence the magnitude of micromotion. 20 arthroplasties with the same design as above but equipped with an intramedullary stem, were randomized to cemented or uncemented fixation in patients with RA. Cement improved the fixation. Uncemented stemmed components displayed micromovements seemingly larger than unstemmed ones. 34 arthroplasties with an unconstrained design of the joint area and fixed to the tibia with four pegs were randomized to cemented or uncemented fixation in patients with OA. When used uncemented 4 screws were added. Compared with previously investigated designs small micromotions were recorded, and especially in the cemented cases. Uncemented components with thin polyethylene inserts displayed larger initial micromotions. The preoperative deformity influenced the direction of the micromotion. 33 knees were followed prospectively with RSA and scintimetry to evaluate any correlation between these methods. Low activity under the tibial component at 2 years implied prosthetic stability, whereas high activity indicated instability or high bone remodelling caused by the preoperative malalignment. The in vivo kinematics in three different designs of knee arthroplasties were analyzed during active flexion and extension without weight-bearing. Each type of prosthesis displayed design-specific abnormalities when compared with a normal material. Pronounced posterior tibial translations were recorded during flexion regardless whether the posterior cruciate ligament had been sacrificed or not. Data from the kinematic and the fixation studies suggest that movements restricted by the design of the joint area are transmitted to the bony interface with design-specific micromotions as the result. Analysis of knee joint kinematics during extension and weight-bearing revealed small alterations compared with non-weight-bearing. Evaluation of the three-dimensional movements in terms of helical axis rotations and translations confirmed the constrained or unconstrained in vivo behaviour of the designs under study. This analysis also facilitated the interpretation of the kinematic behaviour of the prosthetic knees and may be of value in the evaluation of new designs. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1992, härtill 7 uppsatser.</p> / digitalisering@umu
80

Effect of malalignment on knee joint contact mechanics

Reisse, Franziska January 2014 (has links)
Osteoarthritis (OA) is a debilitating joint disease that leads to significant pain, loss of mobility and quality of life. Knee malalignment results in increased joint pressure, which is a primary cause for OA progression. High Tibial Osteotomy (HTO) is a surgical procedure to correct malalignment and redistribute load in the knee joint, reduce peak pressure and delay OA progression. However, clinical outcomes have been unpredictable. Therefore, the aim of this study was to determine the relationship between malalignment and knee contact mechanics. A 3D computational model was created from magnetic resonance images of a cadaveric knee joint. A ligament tuning process was conducted to determine material properties. Finite element analyses were conducted, simulating end of weight acceptance during walking. Different wedge geometries were virtually removed to simulate malalignments from 14° valgus to 16° varus. Contact mechanics were sensitive to soft tissue material properties. In-vitro experiments were compared with computational modelling of the same specimen. Percent full-scale errors for contact force and pressure were less than 8%, demonstrating a unique subject-specific model validation. The native alignment of the cadaveric knee (1° varus) had medial and lateral compartment peak pressures of 4.28 MPa and 2.42 MPa, respectively. The medial:lateral force ratio was 70%:30%. Minimum contact stress did not occur at a Mechanical Axis Deviation (MAD) of zero millimetres nor at the Fujisawa Point, which are common targets for HTO correction. Results showed very strong correlations (r >0.94) between MAD and joint contact loading. This study is the first to demonstrate the relationship between stress (normal, shear, contact pressure) and MAD in a subject-specific model. This is a prerequisite for the development of a tool that could help surgeons make informed decisions on the degree of realignment required to minimise peak joint loading, thereby delaying OA progression.

Page generated in 0.0429 seconds