Design of a carbon fibre rim for a fuel efficient competition vehicle

Motivated by the persistently pursued weight reductions in a vehicle projected for a fuel efficiency competition, this thesis deals with designing new and lighter rims for the vehicle. The aim of the thesis is to design the rims with a carbon-fibre reinforced polymer, a lightweight composite material. A profound study on this kind of material is also presented, since it could be useful for lighten, subsequently, other parts of the vehicle. The thesis is based on a review of literature to acquire a theoretical framework. The design process and its validation is supported by finite element analyses. The preliminary design starts with a closed V profile, which appears to be a viable and adequate option for the application. The rim is divided into three parts, the contour and two sidewalls. By modelling and simulating the rim, the profile of each part is optimized and information about the stress´s state is acquired. Therefore the layered structure for the different parts are defined by taking the optimum proportions of the fibre's orientations into account. The parts are then simulated making use of a layered element which in the end validates the design. The reserve factors found are 1,67 for the contour and around 1,5 for the sidewalls, which indicates the good adjustment of the design between safety and performance. On the other hand, an estimation for the weight reduction is calculated, which achieves values around 17% on the better cases. With further work on the manufacturing process the design can in the end offer a reasonable saving of weight.Outgoin

Fisiopatología de las transposiciones tendinosas

Las transposiciones tendinosas constituyen la base fundamental para la restauración de una función perdida en el miembro paralizado. Los buenos resultados de estas transposiciones requieren no sólo una técnica meticulosa, sino también un conocimiento del comportamiento de los tejidos involucrados en todo el proceso. Los factores que inciden en el resultado de una transposición tendinosa son: a) mecánicos (potencia muscular, trayecto tendinoso y fijación terminal): b) biológicos(irrigación de la transposición, nuevos planos de deslizamiento y cicatrices); c) individuales (edad, dolor y sensibilidad en mano, estado articular previo, antigüedad del proceso y reeducación), y d) técnicos (cirugía precisa y tensión apropiada de la transposición). En este trabajo se analizan los elementos fundamentales constituyentes de una transposición tendinosa: el músculo motor, el tendón transferido y su nuevo trayecto, la fijación del tendón y el estado de las articulacione

Tratamiento quirúrgico percutáneo del hallux valgus mediante osteotomías múltiples

Objetivo: Se presenta la experiencia del tratamiento del hallux valgus mediante la realización de osteotomía distal del primer metatarsiano y osteotomía de la falange con liberación del abductor por técnicas percutáneas. Material y método: Desde junio de 1996 hasta junio de 1997 han sido intervenidos 64 pacientes, la mayor parte mujeres con hallux valgus de grado moderado con un ángulo intermetatarsiano medio de 14.5° y un ángulo del complejo articular proximal (PASA) de 17,7° de media. Resultados: Los resultados obtenidos desde el punto de vista radiológico pusieron de manifiesto una corrección media de 5° del ángulo intermetatarsal y se obtiene un valor medio del PASA de 8,2°. La consolidación de las osteotomías se consiguió en el 100% de los pies sin retardos de consolidación significativos, salvo en un caso que precisó más de tres meses. Por lo que se refiere a las complicaciones, al no utilizar ningún medio de fijación, el desplazamiento de las osteotomías fue muy frecuente, pero sólo en un 8% de la serie tuvieron repercusión clínica. El acortamiento del primer metarsiano fue la norma alcanzando como media 0,7 cm, lo que se intentó compensar con un descenso de la cabeza del primer metatarsiano; la metatarsalgia por trasferencia en esta serie ocurrió en el 25% de los casos. No se presentaron alteraciones neurológicas, infección ni síndromes flebíticos postquiriírgicos. Conclusión: Parece que la técnica de Reverdin-Isham, por vía percutánea, es un buen método para el tratamiento del hallux valgus. ya que proporciona unos resultados clínicos muy aceptables, sin presentar complicaciones importantes; en el momento actual hay que asociar con mucha más frecuencia la realineación metatarsal a la cirugía del hallux valgus para evitar las metatarsalgias por trasferencia

“Web impingement” of the ankle: a case report

This case report presents two patients with persisting anterior ankle impingement pain after an ankle distortion. A web-like intra-articular fibrous band was discovered and resected. The patients presented were, after a 1-year follow-up, pain fre

Minimally invasive management of dorsiflexion contracture at the metatarsophalangeal joint and plantarflexion contracture at the proximal interphalangeal joint of the fifth toe

Several surgical options have been described to manage persistent dorsiflexion contracture at the metatarsophalangeal joint and plantarflexion contracture at the proximal interphalangeal joint of the fifth toe. We describe a minimally invasive technique for the management of this deformity. We perform a plantar closing wedge osteotomy of the 5th toe at the base of its proximal phalanx associated with a lateral condylectomy of the head of the proximal phalanx and at the base of the middle phalanx. Lastly, a complete tenotomy of the deep and superficial flexor tendons and of the tendon of the extensor digitorum longus is undertaken. Correction of cock-up fifth toe deformity is achieved using a minimally invasive approach

Updating of the anatomy of the extensor mechanism of the knee using a three-dimensional viewing technique

The knee extensor mechanism is a complex structure formed by the quadriceps muscle and tendon, the patella, the patellar tendon and the ligaments that surround and help stabilize the knee. Through using a three-dimensional viewing technique on images of the knee extensor apparatus, we aimed to didactically show the structures that compose this bone-muscle-ligament complex. Anatomical dissection of the knee with emphasis on the structures of its extensor mechanism was performed, followed by taking photographs using a camera and lenses suitable for simulating human vision, through a technique for constructing three-dimensional images. Then, with the aid of appropriate software, pairs of images of the same structure from different angles simulating human vision were overlain with the addition of polarizing layer, thereby completing the construction of an anaglyphic image. The main structures of the knee extensor mechanism could be observed with a three-dimensional effect. Among the main benefits relating to this technique, we can highlight that in addition to teaching and studying musculoskeletal anatomy, it has potential use in training for surgical procedures and production of images for diagnostic tests.O mecanismo extensor do joelho é uma estrutura complexa formada pelo músculo e tendão quadricipital, a patela, o tendão patelar e os ligamentos que os circundam e auxiliam na estabilização do joelho. Através do uso de técnica de visualização tridimensional de imagens do aparelho extensor do joelho pretendemos mostrar de forma didática as estruturas que compõem este complexo ósteo-músculo-ligamentar. Dissecção anatômica do joelho com ênfase nas estruturas do seu mecanismo extensor foi realizada seguida de fotografias com câmera e lentes adequadas para simulação da visão humana através de técnica de construção de imagem tridimensional. Em seguida, com a ajuda de software apropriado, as duas imagens da mesma estrutura de diferentes ângulos simulando a visão humana são sobrepostas com adição de camada polarizante, concluindo a construção da imagem anaglífica. As principais estruturas do mecanismo extensor do joelho podem ser observadas com efeito tridimensional. Dentre os principais benefícios relacionados a esta técnica, destacamos, além do ensino e estudo da anatomia musculoesquelética, o potencial uso em treinamento de procedimentos cirúrgicos e a realização de imagens em exames diagnósticos.Universidade Federal de São Paulo (UNIFESP) Departamento de Ortopedia e Traumatologia Centro de Traumatologia do EsporteInstituto CohenSanta Casa de Misericórdia de São Paulo Faculdade de Ciências MédicasFaculdade de Medicina de São José do Rio PretoUniversidade de BarcelonaUNIFESP Departamento de Ortopedia e TraumatologiaCentro de Traumatologia do EsporteUNIFESP, Depto. de Ortopedia e Traumatologia Centro de Traumatologia do EsporteUNIFESP, Depto. de Ortopedia e TraumatologiaSciEL

Anatomy of the ankle ligaments: a pictorial essay

Understanding the anatomy of the ankle ligaments is important for correct diagnosis and treatment. Ankle ligament injury is the most frequent cause of acute ankle pain. Chronic ankle pain often finds its cause in laxity of one of the ankle ligaments. In this pictorial essay, the ligaments around the ankle are grouped, depending on their anatomic orientation, and each of the ankle ligaments is discussed in detail

Patología del quinto radio. Parte III: Quintus Varus

Se comentan las características de la deformidad y su clasificación en función de la radiología. En relación al tratamiento quirúrgico, en los casos leves se propone una exostectomía asociada a un cerclaje fibroso. En los casos severos es necesario añadir a estos gestos quirúrgicos una osteotomía correctora. Los autores proponen una osteotomía basal tipo chevron, la cual tiene como ventaja la obtención de una amplia superficie de contacto así como la posibilidad de ascender el metatarsiano

Anatomy of the ankle ligaments: a pictorial essay

Understanding the anatomy of the ankle ligaments is important for correct diagnosis and treatment. Ankle ligament injury is the most frequent cause of acute ankle pain. Chronic ankle pain often finds its cause in laxity of one of the ankle ligaments. In this pictorial essay, the ligaments around the ankle are grouped, depending on their anatomic orientation, and each of the ankle ligaments is discussed in detail

The course of the superficial peroneal nerve in relation to the ankle position: anatomical study with ankle arthroscopic implications

Despite the fact that the superficial peroneal nerve is the only nerve in the human body that can be made visible; iatrogenic damage to this nerve is the most frequently reported complication in anterior ankle arthroscopy. One of the methods to visualize the nerve is combined ankle plantar flexion and inversion. In the majority of cases, the superficial peroneal nerve can be made visible. The portals for anterior ankle arthroscopy are however created with the ankle in the neutral or slightly dorsiflexed position and not in combined plantar flexion and inversion. The purpose of this study was to undertake an anatomical study to the course of the superficial peroneal nerve in different positions of the foot and ankle. We hypothesize that the anatomical localization of the superficial peroneal nerve changes with different foot and ankle positions. In ten fresh frozen ankle specimens, a window, only affecting the skin, was made at the level of the anterolateral portal for anterior ankle arthroscopy in order to directly visualize the superficial peroneal nerve, or if divided, its terminal branches. Nerve movement was assessed from combined 10° plantar flexion and inversion to 5° dorsiflexion, standardized by the Telos stress device. Also for the 4th toe flexion, flexion of all the toes and for skin tensioning possible nerve movement was determined. The mean superficial peroneal nerve movement was 2.4 mm to the lateral side when the ankle was moved from 10° plantar flexion and inversion to the neutral ankle position and 3.6 mm to the lateral side from 10° plantar flexion and inversion to 5° dorsiflexion. Both displacements were significant (P < 0.01). The nerve consistently moves lateral when the ankle is manoeuvred from combined plantar flexion and inversion to the neutral or dorsiflexed position. If visible, it is therefore advised to create the anterolateral portal medial from the preoperative marking, in order to prevent iatrogenic damage to the superficial peroneal nerve