Thesis. 1975. B.S.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering. / Bibliography: leaf 39. / by Eric Hershler Bott. / B.S.

Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Matthew Valentine Thompson. / B.S.

As lesões ligamentares são provavelmente a causa mais comum de claudicação em membros pélvicos e de afecção degenerativa da cartilagem na articulação femoro-tíbio-patelar, vistas em cães. Objetivou-se avaliar a função biomecânica da articulação do joelho em cães, comparando a medida de deslocamento cranial e a rigidez articular da tíbia em relação ao fêmur com o ligamento cruzado cranial íntegro, seccionado e reparado cirurgicamente. Utilizou-se a máquina Kratos 5002, que permite gravar em tempo real os parâmetros força (N) e deslocamento/deformação em mm. O ensaio consitiu em aplicar força de (N) registrando assim a gaveta cranial. Para o joelho íntegro, a média de deslocamento em milímetros encontrada para três repetições foram de 3,39 ; 3,47; 3,53. Para o joelho lesado foram de 12,96; 13,24; 13,34. Para o joelho reparado foram de 4,05; 4,61; 4,42. Este estudo permite-nos concluir que após lesão a translação cranial do joelho lesado é acrescida em quatro vezes e a rigidez articular é diminuída em uma vez e meia. A análise estatística revelou diferença significante entre os dados do grupo íntegro e lesado, tanto para deslocamento quanto para rigidez (p<0,05). Para o joelho reparado a translação cranial não apresenta diferença estatística significante entretanto mostra que a rigidez articular não volta a normalidade. / Ligamentary lesions are probaly the most comum cause of hind limb lamness and the degenerative disease of the knee joint seem in dogs. The biomechanical function of the knee joint in dogs was made, comparing the cranial translation degree and articular stiffness of the tibia in relation to the femur, in normal joints, joints with rupture of cranial crucial ligament and cirurgicaly repared. Mechanical assays was realized by Kratos 5002 machine, and recorded in real time the parameters of force (N) and translation/deformation, in mm. The assay had consisted in to use a force(N) registering the cranial translation. To the normal knee, the deslocation media founded after 3 repetitions was 3,39 ; 3,47; 3,53. To the knee with surgical section was 12,96; 13,24; 13,34. To the repared knee was 4,05; 4,61; 4,42These study allows to conclude that the cranial translation is added in four times and the articular stiffness is reduced one and a half times when statistically compared. The statistical analysis reveled significant diference between groups to the cranial tranlation e articular stiffness (p<0,05). To the repared knee the cranial translation don?t reveled significant diference but the articular stiffiness seens anormal.

O resultado clínico a longo prazo das osteotomias valgizantes da tíbia depende da obtenção do adequado alinhamento do eixo mecânico pelo procedimento cirúrgico. Essa correção do eixo mecânico é obtida pela adição ou subtração de cunhas ósseas. O tamanho das cunhas pode ser planejado pré-operatoriamente ou determinado durante a cirurgia utilizando controle intraoperatório do alinhamento do membro. Modernamente, o controle intraoperatório pode ser realizado com auxílio de equipamentos de navegação cirúrgica computadorizados. Neste estudo, comparamos os valores dos eixos mecânicos e dos tamanhos das cunhas obtidos pelo método de planejamento pré-operatório das osteotomias com cálculo trigonométrico e pelas cirurgias auxiliadas por sistema de navegação intraoperatória. A medida dos eixos mecânicos em imagens radiográficas panorâmicas dos membros inferiores foi realizada por catorze cirurgiões de joelho em treze pacientes. A cirurgia de osteotomia valgizante auxilada por navegação cirúrgica foi realizada pelo mesmo cirurgião nos mesmos treze pacientes, documentando-se o tamanho da cunha de adição medial e os eixos mecânicos do membro inferior. Após as cirurgias, planejamos os tamanhos das cunhas de adição medial, por cálculo trigonométrico, utilizando os dados dos eixos mecânicos medidos nas radiografias. Nós realizamos comparação entre os valores dos eixos mecânicos obtidos nas cirurgias e os valores medidos nas imagens radiográficas e entre os tamanhos das cunhas de adição medial medidos intraoperatoriamente e planejadas nos cálculos trigonométricos. A análise dos dados foi realizada por análise descritiva dos resultados e por gráficos de Bland e Altman. Como resultados, observamos alta correlação entre os valores dos eixos mecânicos medidos nos exames radiográficos e pelo navegador cirúrgico e observamos que os valores planejados para as cunhas de adição são diferentes dos valores medidos durante as cirurgias / The long-term clinical outcome of tibial osteotomy depends on achieving the proper mechanical axis alignment for the surgery. Adding or subtracting bone wedges obtains the mechanical axis correction. The correction size may be planned preoperatively or defined during surgery under limb alignment control. Nowadays, the limb alignment control may be accomplished with the aid of computerized surgical navigation equipment. In this study, we compared the values of the mechanical axes and the wedges sizes obtained by the osteotomies preoperative planning method with trigonometric calculation and those values measured on navigated surgeries. Fourteen knee surgeons performed the measurement of the mechanical axes in panoramic radiographs of the lower limbs of thirteen patients. The same surgeon performed all thirteen surgeries. The wedges sizes and the mechanical axes of the lower limb were measured during surgeries. After surgery, the sizes of the planned addition of medial wedges, for trigonometric calculation, using data from the mechanical axis measured on the radiographs. We carry out comparison between the values of the mechanical axes obtained in the surgeries and the values measured in the radiographs and between the sizes of the wedges and wedge sizes planned in trigonometric calculations. We performed data analyses by descriptive analysis and Bland and Altman. We have observed a high correlation between the values of the mechanical axes measured on radiographs and in navigated surgeries and noticed that the planned values for wedges are different from values measured during surgery

It has been found that magneto-rheological (MR) devices can produce large controllable force/torque while consuming little power. In this research, an MR actuator that can function as a clutch or a brake is developed, in order to be applied to an assistive knee brace. The torque capability and dynamic characteristics of the MR actuator are evaluated. The relationship between the torque output and the applied coil current is given. The response time is also measured. Experimental results show that the MR actuator can provide enough torque for normal activities with sufficiently fast response. IP control and adaptive control are proposed to control the MR actuator. Experiments under these controls are carried out. With anti-windup strategies, both controls achieve good performances. However, adaptive control would be more promising since it can adapt to parameter variations and maintain good performance. An assistive knee brace that contains this MR actuator and a DC motor is developed. In order to study the performances of the knee brace before applied to human body, experiments are conducted for evaluation under a custom-built testing structure. IP-based state control and adaptive control are used to control both the MR actuator and DC motor. Experimental results demonstrate that the MR actuator and DC motor work well together to provide assistance as expected. Compared with that without MR actuator, the evaluation results show that the knee brace with MR actuator is more energy efficient during normal walking, while having better force controllability and safety. / by Chen, Jinzhou. / Adviser: Liao Wei Hsin. / Source: Dissertation Abstracts International, Volume: 73-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 140-151). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

In this research, a novel magnetorheological (MR) fluids based multifunctional actuator for assistive knee braces is designed. To decrease the dimension of the actuation device while enhancing its perfonnances, a motor and MR fluids are integrated into a single device. With MR fluids, the actuator possesses multiple functions as motor, clutch, and brake while meeting the requirement of nonnal human motion as well. In this thesis, design details and operating principle of the actuator are illustrated, and possible configurations of the motor part and clutch/brake part are discussed. Finite element method is utilized to analyze the magnetic circuits, influence of pennanent magnet on MR fluids, and magnetic flux distribution. Different clutch/brake parts with various inner coils are compared and analyzed, followed by a design optimization to improve the output torque. Prototypes of the multifunctional actuator are fabricated and tested, and characteristics of each function are investigated. As the actuator has multiple functions, modeling is developed for different functions, and system identification is carried out to determine the parameters. Adaptive control is utilized to control the actuator for torque and speed tracking. A smart joint using such a multifunctional actuator is designed, and its prototype is fabricated and tested. Power consumptions of knee brace using the smart joint are investigated during normal walking cycle. The results show that the developed actuator and smart joint are promising to be used in assistive knee braces. / Guo, Hongtao. / Source: Dissertation Abstracts International, Volume: 73-03, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 154-158). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Thesis. 1978. M.S.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 66-67. / by Mark L. Tanquary. / M.S.

A hiperextensão dos joelhos pode comprometer o controle postural durante o salto vertical. Desta forma, o objetivo deste estudo foi analisar o deslocamento do Centro de Pressão (CP) e o movimento em membros inferiores durante o salto vertical de sujeitos com joelhos hiperestendidos comparativamente com sujeitos com joelhos alinhados no período de preparo do salto. Dezesseis mulheres foram analisadas durante o salto vertical, através de uma plataforma de força modelo AMTI. Os sujeitos foram enquadrados nos grupos Sujeito-Hiperestendido (n=11) e Sujeito-Alinhados (n=5) de acordo com o alinhamento dos joelhos na avaliação postural tradicional e a análise dos dados cinématicos foram efetuadas. Os sujeitos foram orientados a se posicionar sobre uma plataforma de força e saltar o mais alto possível. A cinemática foi adquirida através de câmera em posição padronizada ao lado direito do sujeito que teve os seguintes pontos anatômicos marcados: 5º metatarso, maléolo lateral, cabeça da fíbula e trocânter maior. A fase de preparo e de impulso, neste estudo chamado de fase de preparo, foi determinada pela curva de velocidade angular do joelho. A aterrissagem foi analisada no 1s, 2s e 3s após aterrissagem. Foram calculados para comparação o CP-AP, o CP-ML e o ângulo e velocidade angular máxima e mínima do tornozelo e joelho. Comparação intergrupos dos intervalos de interesse foi realizada aplicando-se Teste de Mann- Whitney aos dados (p<0.05). Comparação intragrupo, entre os intervalos de interesse foi realizada aplicando-se o teste de Friedman seguido do teste de Wilcoxon (p<0.05). Este estudo revelou que indivíduos com hiperextensão de joelhos apresentam controle postural diferente dos com joelhos alinhados durante a execução do salto vertical. Durante a fase de preparo os indivíduos com joelhos hiperextendidos apresentam maior ângulo de extensão de joelhos e maior deslocamento lateral do COP. Durante a fase de aterrissagem os indivíduos com joelhos hiperextendidos apresentam maior ângulo de extensão e menor ângulo de flexão demandando menor deslocamento lateral do COP do que os indivíduos alinhados / Postural misalignment of knee such as hyperextended knees may compromise postural control during vertical jump. Therefore, the aim of this study was to analyze COP and lower limbs movements during vertical jump comparing individuals with hyperextended and aligned knees. Sixteen young and healthy women were analyzed during their maximal vertical jump using a MTI force plate. Subjects were classified as hyperextended (n=11) or aligned (n=5) knees according to clinical observation of knee angle. Subjects were asked to stand still on the force plate and then jump as high as possible. Kinematic data were acquired using a camera located in standardized position at the right side of the subject. Anatomical landmarks were placed at the right side at: 5º metatarsal, lateral malleolus, head of fibula and greater throcanter. The phase of preparation associated to the phase of propulsion was called in this study the phase of preparation. This phase was established based on the curve of angular velocity of the knee. Landing was analyzed in the first, second and third second immediately after landing. COP-AP, VM-AP, COPML and VM-ML were calculated. Kinematic parameters were maximum and minimum ankle and knee angle and angular velocity. Intergroup comparison was carried using Mann-Whitney Test (p<0.05). Intergroup comparison was carried using Friedman Test followed by Wilcoxon Test (p<0.05). This study revealed that subjects with hyperextended knee present different postural control compared to the subjects with aligned knees while performing a vertical jump. During the phase of preparation subjects with hyperextended knees revealed higher angle of knee extension and lower COP-ML displacement. During the phase of landing subjects with hyperextended knees present higher angle of knee extension and lower angle of knee flexion requiring lower displacement of COP-ML when compared to subjects with aligned knee

INTRODUÇÃO: Estudo prévio do nosso grupo demonstrou que uso de palmilha em cunha medial associada ao estabilizador de tornozelo produz uma melhora clínica na osteoartrite do joelho valgo. No entanto, não existem dados na literatura sobre os efeitos biomecânicos destas órteses. OBJETIVO: Avaliação biomecânica dos pés, de maneira estática e dinâmica na osteoartrite do joelho valgo com a utilização de palmilha em cunha medial associada ao estabilizador de tornozelo. MÉTODO: Um total de 42 pés de 21 mulheres com osteoartrite de joelho bilateral (critérios ACR) e deformidade em valgo > 8 graus, foram avaliadas quanto a dados clínicos e biometria. As pacientes foram avaliadas em esteira ergométrica elétrica com: 1. calçado padrão sem a palmilha (controle), 2. palmilha em cunha medial (com 8 mm de elevação medial no retropé) e 3. com essas palmilhas e estabilizador de tornozelo em neoprene. O sistema FSCAN® versão 3.816, com palmilhas flexíveis e 960 sensores de carga na superfície foi utilizado para obter a força plantar vertical. RESULTADOS: Houve redução no pico de pressão plantar estático (PP) com a utilização da palmilha em cunha (P = 0,001) e com a palmilha e estabilizador (P < 0,001) vs. controle em ambos os lados. Além disso, o uso da palmilha associada ao estabilizador de tornozelo resultou em uma redução mais efetiva neste parâmetro em comparação ao uso somente da palmilha (P = 0,027). A avaliação dinâmica deste parâmetro revelou resultado similar no lado direito, com uma redução mais significativa com o uso da palmilha (P < 0,001) e com palmilha e estabilizador de tornozelo (P < 0,001) em relação ao controle. Não foi observada diferença no lado esquerdo (osteoartrite mais grave). A força vertical máxima estática (FVM) também demonstrou diminuição em ambos os lados com o uso da palmilha (P = 0,001) e palmilha associada ao estabilizador de tornozelo (P < 0,001) em relação ao controle. Além disso, o uso da palmilha associada ao estabilizador de tornozelo resultou em uma redução mais efetiva da força vertical máxima estática em comparação ao uso somente da palmilha (P = 0,041). Da mesma forma, na condição dinâmica, esse parâmetro foi significativamente reduzido com o uso da palmilha associada ao estabilizador de tornozelo em comparação à condição controle (P < 0,001). Também houve redução na FVM entre o uso de palmilha com e sem estabilizador (P = 0,003). A avaliação qualitativa revelou que a órtese altera significativamente a trajetória do vetor de força (P < 0,001). CONCLUSÃO: O uso da palmilha em cunha medial associada ao estabilizador de tornozelo promoveu uma redução no pico de pressão plantar e na força vertical máxima em condições estática e dinâmica, subjacente à melhora clínica na osteoartrite do joelho valgo / INTRODUCTION: We have previously demonstrated a significant clinical improvement in valgus knee osteoarthritis with the use of medial-wedge insole associated with ankle support. There is, however, no data regarding the foot plantar forces underlying this beneficial effect. Objective: Static and dynamic feet plantar biomechanical evaluation of medial-wedge insole associated with ankle support in valgus knee osteoarthritis. METHOD: A total of 42 feet of 21 women with bilateral knee osteoarthritis (ACR criteria), with valgus deformity were evaluated regarding clinical and biometric data. Patients were assessed with: 1. standard shoes without the insoles (control); 2. medial-wedge insole; 3. insoles/neoprene ankle support. The system FSCAN® 3816 version, with flexible soles and 960 load sensors on the surface was used to obtain the foot plantar vertical forces. RESULTS: A decreased peak plantar pressure was observed with insoles (P = 0,001) and insoles/ankle support (P < 0,001) vs. control while standing motionless in both sides. In addition, insoles/ankle support resulted in a more effective reduction in this parameter than solely insoles (P = 0,027). The dynamic evaluation of this parameter revealed a similar finding on the right side with a more significant reduction with use of insoles (P < 0,001) and with insoles/ankle support (P < 0,001) compared to controls. No difference was observed on the left side (more severe OA). The static maximum vertical force was also decreased in both sides with insoles (P = 0,001) and insoles/ankle support (P < 0,001) compared to control. In addition, the later condition provided a more significant reduction in the static maximum vertical force than solely insoles (P = 0,041). Likewise, in the dynamic condition this parameter was significantly reduced with insoles/ankle support compared with control condition (P < 0,001) and solely insoles (P = 0,003). The qualitative evaluation revealed that orthoses significantly changed the center of force shift (P < 0,001). CONCLUSION: We have identified that a reduction in the feet plantar peak and maximum vertical force in valgus knee osteoarthritis in static and dynamic conditions underlies the clinical improvement of medial-wedge insole associated with ankle support

The purpose of this study was to examine the independent effects of anterior knee pain (AKP) on bilateral ground reaction force (GRF) during running, with a focus on GRF applied to the uninvolved leg, which, prior to this study, had never been evaluated. Twelve volunteers completed three data collection sessions, that corresponded to one of three conditions (control, sham, and pain), in a counterbalanced order. For each session, subjects ran for five minutes. For the pain and sham sessions, respectively, hypertonic and isotonic saline were infused into the infrapatellar fat pad of the right leg during the running, while no infusion was involved in the control session. GRF data were collected during the final 30 seconds of running. Functional statistics were used to determine the effects of session and leg (right and left) on vertical and anterior-posterior GRF throughout the stance phase of running. A mixed model ANOVA was used to determine the effect of session and leg on vertical GRF load rate, impulse due to vertical, propulsive, and braking GRFs. A repeated measures ANOVA was used to determine the effect of session and time on subject-perceived pain. Alpha was set to 0.05 for all statistical comparisons. Unexpectedly, no significant session × leg interaction existed for vertical GRF at any time point during stance phase of running. Similarly, the experimental AKP did not affect impulse due to vertical GRF or load rate for the vertical GRF. There was, however, a significant session × leg interaction for anterior-posterior GRF. For the pain session, involved-leg braking GRF was 11% greater than uninvolved-leg braking GRF, during the first 9% of stance phase. There was also a significant between-session difference for involved-leg braking impulse (p = 0.023) and uninvolved-leg propulsive impulse (p = 0.027). The mean involved-leg braking impulses were 11.3 Ns (± 0.6), 13.2 Ns (± 0.6) and 13.2 Ns (± 0.6) for the pain, control, and sham sessions, respectively. Mean uninvolved-leg propulsive impulses were 14.8 Ns (± 1.3), 13.6 Ns (± 1.3), and 13.5 Ns (± 1.3) for the pain, control, and sham sessions, respectively. These differences in anterior-posterior GRF might reflect a compensatory unloading of the involved leg due to AKP.