L'ingénierie tissulaire est une discipline récente aux enjeux ambitieux et prometteurs : la régénération de tissus ou d'organes lésés voire détruits en mettant à profit des connaissances et compétences dans différents domaines à l'interface de la chimie et de la biologie. Pour répondre à la demande d'alternatives aux techniques chirurgicales actuelles de réparation du ligament antérieur croisé, nous avons décidé d'appliquer l'ingénierie tissulaire à ce tissu en associant matrices en polymères dégradables et cellules souches mésenchymateuses (CSM). Dans un premier temps, nous avons donc travaillé à la synthèse de polymères adaptés à l'application en cherchant à mettre l'accent sur l'obtention de propriétés élastiques. De nouveaux élastomères dégradables obtenus par des approches originales de photoréticulation chimique de poly(lactide) (PLA) et de poly(ε-caprolactone) (PCL) par voie nitrène ou thiol-yne ont notamment été développés avec des résultats prometteurs. En parallèle, des copolymères thermoplastiques multiblocs à base de PLA et poloxamine ou poloxamère nous ont permis de mener une étude plus appliquée. Ces copolymères ont en effet montré, en particulier au cours d'une étude de dégradation in vitro de 7 semaines, des propriétés, notamment thermiques et mécaniques, qui en font d'eux des candidats intéressants pour le conception d'une matrice ligamentaire. C'est pourquoi ils ont été utilisés pour la conception de prototypes de matrices de régénération textiles dont les propriétés mécaniques se sont révélées être très proches de celles du ligament. Après avoir démontré l'excellente cytocompatibilité de ces matrices avec des CSM, nous avons finalement mené des expériences de différenciation in vitro de ces CSM et sommes parvenus à favoriser leur orientation vers un phénotype ligamentocytaire, notamment grâce à un procédé de stimulation mécanique cyclique des cellules ensemencées sur les matrices textiles. / Tissue engineering is a recent discipline with ambitious and promising stakes: the regeneration of wounded or destroyed tissues or organs by taking advantage of knowledge and skills in various fields at the interface of chemistry and biology. In order to meet the need for alternatives to current surgical techniques of anterior cruciate ligament repair, we decided to apply the tissue engineering approach to this tissue by associating degradable polymer scaffolds and mesenchymal stem cells (MSCs). At first we worked on the synthesis of biodegradable polymers suitable for the application and focused on getting elastic properties. New degradable elastomers obtained by chemical photocrosslinking of poly(lactide) (PLA) and poly(ε-caprolactone) (PCL) were developed by following nitrene or thiol-yne strategies and yielded promising results. In parallel, a more in depth and practical study was performed with PLA based thermoplastic multiblock copolymers embedding poloxamer or poloxamine. These copolymers exhibited properties that make them attractive candidates for the design of ligament regeneration scaffolds, and especially their thermal and mechanical properties during a 7 week in vitro degradation test. That is why they were used to design prototypes of textile scaffolds whose mechanical properties were found to be very close to the ligament's ones. After demonstrating the excellent cytocompatibility of these scaffolds with MSCs, we finally carried out in vitro differentiation experiments on these MSCs and managed to induce their orientation towards a ligamentocyte phenotype, particularly through a process of cyclic mechanical stimulation of cells seeded on the textile scaffolds.

Il a été démontré que les reconstructions du ligament croisé antérieur (ACL) ne permettaient pas un contrôle parfait de l’instabilité rotatoire antérolatérale (ALRI). Ce postulat a conduit à la redécouverte du ligament antérolatéral (ALL). Toutefois de nombreuses questions persistent, rendant sa reconstruction chirurgicale approximative.Après avoir établi un protocole de dissection non extensif, les principales caractéristiques anatomiques du ALL ont été définies. Puis, une description histologique du ALL a été réalisé afin de confirmer sa nature ligamentaire.Deuxièmement, grâce à la mise au point et à la validation d’un protocole d’analyse cinématique par système optoélectronique tridimensionnel, nous avons pu étudier le rôle du ALL sur la stabilité du genou. A travers une analyse des variations de sa longueur au cours du mouvement, et des conséquences de sa section, nous avons déterminé son rôle sur le contrôle de la l’ALRI.Troisièmement, une technique de reconstruction physiologique du ALL, modifiée selon nos résultats, a été proposée. Afin de l’évaluer, nous avons analysé les cinématiques du genou après cette reconstruction en les comparant avec celles obtenues après une ténodèse latérale extra-articulaire.Enfin, afin de préciser ses indications de reconstruction, différents outils cliniques (laximétrie, accéléromètre triaxial), et morphologiques (IRM, échographie) ont été analysés afin d’évaluer leurs pertinences dans le diagnostic de rupture du ALL.En conclusion, ce travail donne une vue d’ensemble globale du ALL, de sa description anatomique et histologique, en passant par sa fonction biomécanique, jusqu’à à sa reconstruction chirurgicale / Many clinical studies have shown that anterior cruciate ligament (ACL) anatomical reconstruction do not allow a perfect control of anterolateral rotational instability (ALRI). This clinical postulate led to rediscovery of the anterolateral ligament (ALL). However ALL surgical reconstruction are still approximate, due to a lack of knowledge.Initially, we have studied cadaveric knees, using our own non-extensive and reproducible dissection protocol. With tis approach, we were able to define the anatomical parameters relevant to obtaining an effective ALL reconstruction. Then, we performed an histological study in order to confirm ALL ligamentary structure.In a second part, we have developed and validated a kinematic analysis protocol using a three-dimensional optoelectronic system to study the ALL role on the knee stability. Through an analysis of ALL length variations during motion and ALL section consequences, we determined the ALL capacity on ALRI control.In a third part, we were able to define, regarding our previous results, biomechanical and anatomical imperatives to perform an anatomic ALL reconstruction. In order to evaluate this technique, we analyzed and compared knee kinematics after ALL reconstruction and after lateral extra-articular tenodesis on cadaveric knees.Lastly, various clinical (laximeter, triaxial accelerometer) and morphological (MRI, ultrasound) systems were analyzed to evaluate their relevance in ALL tear diagnosis, in order to improve ALL reconstruction indications.In conclusion, this work gives a global view of ALL, from anatomical description and biomechanical function to surgical reconstruction.

As lesões do ligamento cruzado posterior (LCP) geralmente estão associadas a traumas de alta energia. Ainda existem muitas controvérsias sobre a técnica cirúrgica ideal para o tratamento dessas lesões, no que diz respeito aos métodos de seleção e fixação do enxerto. A técnica onlay, recentemente descrita, permite a fixação direta de um autoenxerto de tendões flexores ao aspecto posterior da tíbia com parafuso esponjoso e arruela dentada plástica, com proteção às estruturas neurovasculares e evitando a chamada \"curva assassina\". O objetivo deste estudo foi realizar uma avaliação biomecânica da técnica onlay, comparando entre si as fixações tibiais unicortical e bicortical de enxertos, imediatamente após o implante (tempo zero). O ensaio biomecânico e a coleta de dados foram realizados no Thompson Laboratory for Regenerative Orthopaedic da Universidade de Missouri (Columbia, Missouri, EUA). Para isso, oito joelhos de espécimes cadavéricos foram distribuídos aleatoriamente em uma das duas técnicas de fixação do LCP (n = 4 joelhos/técnica), que foram realizadas por cirurgiões experientes no procedimento. O teste biomecânico consistiu em uma força com direção posterior aplicada a região proximal da tíbia, em quatro ângulos de flexão do joelho, 10o, 30o, 60o e 90o. O teste foi realizado com uma taxa de deslocamento de 1 mm/s, em uma máquina servo-hidráulica (8821s, Instron, Norwood, MA). As variáveis medidas foram: carga para 5 mm de deslocamento posterior, deslocamento máximo (com carga de 100 N) e rigidez. Para a análise estatística, os dados de cada joelho foram normalizados para o joelho com LCP nativo intacto e depois agrupados nas categorias unicortical ou bicortical, de acordo com a fixação realizada. Dados obtidos, nas variáveis mencionadas, para os grupos joelho intacto, joelho desbridado, unicortical e bicortical, foram comparados por meio da análise de variância simples (one-way ANOVA) para avaliar diferenças estatisticamente significativas (p < 0,05). Quando comparadas aos joelhos com LCP desbridado, as técnicas de fixação unicortical e bicortical apresentaram menor frouxidão a uma carga máxima de 100N. Quando comparados com os joelhos intactos, o grupo unicortical apresentou maior frouxidão em todos os ângulos e o grupo bicortical apresentou maior frouxidão apenas a 90o de flexão (p < 0,001). Na avaliação da força relativa do enxerto, ou seja, a carga necessária para atingir 5 mm de deslocamento na gaveta posterior, as técnicas unicortical e bicortical exigiram menos carga que os joelhos com LCP intacto. O grupo com fixação bicortical, no entanto, foi superior ao unicortical em todos os ângulos (p < 0,001), na avaliação da força relativa. Em relação à rigidez, não houve diferenças significativas entre os grupos unicortical e bicortical e ambos foram superiores aos joelhos desbridados e inferiores aos joelhos com LCP intacto. Com base nos testes biomecânicos de cadáveres, nenhuma das técnicas de reconstrução do LCP foi capaz de reproduzir os resultados do joelho com LCP intacto, mas ambas as técnicas foram superiores aos joelhos com deficiência de LCP. Ao se optar pela técnica onlay de reconstrução do LCP, a técnica de fixação tibial bicortical parece ter vantagens biomecânicas em relação à técnica de fixação unicortical. / Posterior cruciate ligament (PCL) injuries are generally associated with high energy trauma. There are many controversies regarding optimal surgical technique in regard to graft selection and fixation methods. The recently described onlay technique allows for direct fixation of a hamstring autograft to the posterior aspect of the tibia, protecting the neurovascular structures and avoiding the so-called \"killer turn\". The onlay technique requires a cancellous screw and spiked washer to secure the graft to the tibia. The objective of this study was to compare immediate post-implantation biomechanics of unicortical versus bicortical tibial fixation of onlay PCL grafts. Biomechanical testing and data collection were performed at the Thompson Laboratory for Regenerative Orthopedics at the University of Missouri (Columbia-Missouri-USA). For that, eight knees were randomly assigned to one of two onlay PCL techniques (n= 4 knees/technique), performed by surgeons experienced with the procedure. Testing consisted of a posterior-directed force at four knee flexion angles, 10, 30, 60, and 90 degrees, at a displacement rate of 1 mm/s, performed in a servo-hydraulic machine (8821s, Instron, Norwood, MA). Measured variables were: load to 5 mm of posterior displacement, maximum displacement (at 100 N load) and stiffness. For statistical analyses, data for each knee were normalized to the native PCL-intact knee and then grouped into unicortical or bicortical groups accordingly. Data for load to 5 mm (strength), displacement at 100 N, and stiffness were compared among PCL-intact, PCL-deficient, unicortical fixation, and bicortical fixation categories using one-way analysis of variance (ANOVA) to assess for statistically significant (p < 0.05) differences. When compared to PCL-deficient knees, both unicortical and bicortical fixation techniques had less laxity at a maximum load of 100N. When compared with PCL-intact knees, unicortical had more laxity at all angles and bicortical had more laxity only at 90 degrees (p < 0.001). For relative graft strength, namely the load required to reach 5mm of displacement in posterior drawer, unicortical and bicortical techniques required less load to 5 mm of posterior drawer than for PCL-intact knees. Bicortical, however, outperformed unicortical at all angles (p < 0.001) for relative strength. Regarding stiffness of each construct, there were no significant differences between unicortical and bicortical and both were superior to PCL-deficient and inferior to PCL-intact knees. Based on cadaveric biomechanical testing, none of the reconstructed PCL knees was able to replicate the intact native PCL, but both techniques were superior to PCLdeficient knees. The bicortical tibial fixation technique appears to have biomechanical advantages when opting for onlay PCL reconstruction.

INTRODUÇÃO: Anualmente nos E.U. A, estima-se mais de 250.000 mil casos de lesão do ligamento cruzado anterior, o que torna a reconstrução cirúrgica um procedimento comum na pratica da medicina esportiva. Ainda não existe consenso sobre o quanto de atividade promove uma reabilitação adequada sem prejudicar o enxerto ou produzir uma frouxidão anterior anormal, com consequente dano ao menisco e a cartilagem articular. OBJETIVO: Analisar e comparar o efeito de um protocolo de fisioterapia acelerado na estabilidade anterior e evolução clínica dos indivíduos submetidos à reconstrução do ligamento cruzado anterior. MÉTODOS: Foram incluídos 29 indivíduos no estudo que apresentaram ruptura total do LCA confirmada por RM e submetidos à reconstrução ligamentar com Tendão patelar. Aleatoriamente foram alocados em dois grupos com intervalos de reabilitação diferentes: Grupo Acelerado (4 meses) ou Grupo Convencional (6 meses). No pré-operatório, sexto e no quarto mês de pós-operatório um avaliador cego registrou: a lassidão anterior através do KT1000, Força muscular (CYBEX) e a função do joelho acometido através do IKDC (2000) e o Hop Test. RESULTADOS: os grupos foram semelhantes em relação aos dados demográficos. Não foi encontrada diferença estatística na lassidão anterior no quarto mês 0,92mm versus 1,33mm e no sexto mês 0,50mm versus 1,67mm sendo Grupo Convencional versus Grupo Acelerado respectivamente. No quarto mês o Grupo Acelerado apresentou uma melhora significativa (P< 0,001) na evolução clínica do IKDC (2000) 79,50 versus 60,61 do Grupo Convencional, essa diferença não se repetiu no sexto mês. A força muscular e o Hop Test, o Grupo Acelerado apresentou maiores valores, mas não de forma significativa nos dois momentos de avaliação (P> 0.05). CONCLUSÃO: Com base nos resultados obtidos, o protocolo acelerado quando comparado ao Convencional, não se diferiu quanto à estabilidade anterior do joelho e foi suficiente para demonstrar uma melhora significativa precoce na evolução clínica do joelho / BACKGROUND: Each year in the US, it is estimated more than 250 million cases of anterior cruciate ligament injury, which makes surgical reconstruction a common procedure in the practice of sports medicine. There is still no consensus on how much activity to promote adequate rehabilitation without damaging the graft or produce an abnormal anterior laxity, with consequent damage to the meniscus and articular cartilage. PURPOSE: To analyze and compare the effect of an accelerated physiotherapy protocol in the anterior-stability and clinical outcome of patients undergoing reconstruction of the anterior cruciate ligament. METHODS: We included 29 subjects in the study who had total ACL rupture confirmed by MRI and underwent ligament reconstruction with patellar tendon. Patients were randomly allocated in two groups with different rehabilitation intervals: Accelerated Group (4 months) or Conventional Group (6 months). Preoperatively, six and four months postoperatively a blind evaluator recorded: anterior laxity by KT1000, Brawn (CYBEX) and knee function affected by IKDC (2000) and the Hop Test. RESULTS: the groups were similar relative to demographic data. There was no statistical difference in anterior laxity in the fourth month 0,92mm versus 1.33mm and 0.50mm in the sixth month versus 1,67mm being conventional group versus accelerated group respectively. In the fourth month the accelerated group showed a significant improvement (P <0.001) in the clinical evolution of the IKDC (2000) 79.50 versus 60.61 in the conventional group, this difference was not repeated in the sixth month. Muscle strength and the Hop Test, the fast group had higher values, but not significantly in both time points (P> 0.05). CONCLUSION: Based on these results, the Accelerated protocol when compared to conventional, do not differ as the anterior knee stability and was sufficient to establish an early significant improvement in the clinical outcome of the knee

Introdução: A função principal do ligamento anterolateral (LAL) é a restrição secundária da rotação medial da tíbia, alterando o teste Pivot shift. Os estudos evidenciam uma piora da estabilidade rotacional quando há lesão do LAL associada ao ligamento cruzado anterior (LCA), que é melhorada após a reconstrução combinada desses ligamentos, mas quanto às alterações na função muscular, não há esclarecimento na literatura de como esses indivíduos se comportam. Objetivo: Analisar se há diferença na função muscular flexora e extensora do joelho e abdutora do quadril entre os grupos com indicação para reconstrução combinada do LCA e LAL (grupo LCA+LAL) e reconstrução isolada do LCA (grupo LCA), e secundariamente realizar avaliação clínica e da funcionalidade. Métodos: Avaliação por dinamometria isocinética para o objetivo primário utilizando as velocidades angulares 60º/s para o quadril e 60 e 120º/s para o joelho e para o secundário, uso da escala Lysholm e testes funcionais, como o Single Hop Test e Cross Over Hop Test e avaliação clínica da dor, pela escala visual analógica; translação anterior da tíbia, com o artrômetro (KT-1000) e perimetria do joelho e da coxa (fita métrica). Resultados: Nenhuma diferença foi encontrada quanto a função muscular do quadril e joelho no membro acometido ao se comparar os grupos LCA+LAL e LCA. Entretanto, observou-se um menor trabalho total extensor a 60º/s no membro contralateral ao lesionado observada no grupo LCA+LAL em relação ao grupo LCA e na avaliação da diferença entre os membros houve uma maior diferença entre eles no grupo LCA referente a função extensora do joelho (pico de torque, trabalho total e relação agonista/antagonista) a 60º/s, o que também ocorreu a 120º/s para o trabalho total extensor e relação agonista/antagonista do joelho para esse grupo. Quanto as variáveis secundárias, 68,9% do grupo LCA+LAL referiram dor no joelho e 61,9% no grupo LCA e houve um aumento significativo da translação anterior da tíbia no LCA+LAL em relação ao LCA. Conclusão: Não há diferença entre os grupos LCA+LAL e LCA no que se refere a função muscular do quadril e joelho e funcionalidade. O grupo LCA+LAL apresentou uma maior translação anterior da tíbia em relação ao grupo LCA / Introduction: The main function of the anterolateral ligament (ALL) is the secondary restriction of tibial medial rotation, resulting in a change on the Pivot shift test. Studies show a worse rotational stability when there is an ALL lesion associated with an anterior cruciate ligament (ACL) lesion, which is improved after the combined reconstruction of these ligaments. Regarding the alterations on muscle function, there is no understanding in the literature on how these individuals behave. Purpose: To analyze if there is a difference in the muscle function (knee flexor and extensor and hip abductor) between the groups with indication for combined ACL and ALL reconstruction (ACL+ALL group) and isolated ACL reconstruction (ACL group). Secondarily, to do a clinical and functional evaluation. Methods: Isokinetic dynamometry for the primary objective using 60º/s angular velocities for the hip and 60 and 120º/s for the knee. Secondarily, the use of the Lysholm scale and functional tests, such as Single Hop Test and Cross Over Hop Test and clinical evaluation of pain by visual analogue scale; anterior translation of the tibia, with the arthrometer (KT-1000) and perimetry of the knee and thigh (tape measure). Results: No differences were found regarding hip and knee muscle function in the affected limb when the ACL+ALL and ACL groups were compared. However, there was a lower total extensor work at 60º/s in the limb contralateral to the lesion observed in the ACL+ALL group in relation to the ACL group. Evaluating the difference between the members there was a greater difference between them in the ACL group (peak torque, total work and agonist/antagonist ratio) at 60º/s, which also occurred at 120º/s for total extensor work and knee agonist / antagonist relation for this group. Regarding the secondary variables, 68.9% of the ACL+ALL group reported knee pain and 61.9% in the ACL group, and there was a significant increase in anterior tibial translation in the ACL+ALL group in relation to the ACL group. Conclusion: There is no difference between ACL+ALL and ACL groups regarding hip and knee muscle function and functionality. The ACL+ALL group presented a greater anterior translation of the tibia in relation to the ACL group

Cette thèse s’est d’abord voulue pratique. La chirurgie de l’épaule est en pleine expansion avec le vieillissement croissant de la population et la pratique de plus en plus généralisée du sport. L’épaule est une articulation complexe. Paradoxalement les progrès techniques en chirurgie sont sans cesse grandissants et renouvelés tandis que l’on tientpour acquis des données anatomiques démontrées il y a longtemps et rapportées jusqu’à nos jours. Nous avons voulu confronter l’anatomie avec les techniques diagnostiques actuelles et voir si cela pouvait avoir un impact sur les pratiques chirurgicales. Nous avons également voulu voir si certaines complications chirurgicales pouvaient s’expliquer par des données anatomiques. Ce qui a orienté nos recherches sont les principaux problèmes actuels en pathologie de l’épaule c’est-à-dire la coiffe des rotateurs et le syndrome sous-acromial. Les observations lors des nombreuses dissections de l’épaule nous ont conduit à ces réflexions : comment la glène est-elle vascularisée?, pourquoi est-elle si fragile?, que se passe-t- il dans l’espace sous acromial?, quelle est l’utilité du ligament coraco-acromial?, quels sont ses rapports avec lesuprapinatus?, pourquoi l’insertion du supraspinatus est-elle fragile et difficile à reconstituer ?, la qualité osseuse de la tête humérale a-t-elle un impact sur la géographie des fractures, les échecs des ostéosynthèses, les descellements prothétiques?, qu’est ce que la chape delto-trapézoidienne? Autant de questions que nous nous sommes posées endisséquant cette articulation très complexe qui est l’épaule. Par ailleurs, l’anatomie classique peut maintenant secompléter non seulement de l’histologie, mais aussi de techniques radiologiques modernes comme l’IRM l, le microCT, le synchrotron, la reconstruction 3D, la modélisation en éléments finis. / I would like to make a practical thesis. Shoulder surgery is growing and growing as the population is ageing and people is doing more and more sports activities. A lot of technical progress were done but there are still a lot of surgical complications. On the other way some very old anatomical ideas are still alive. I want to see with the actual knowledge, if some surgical complications could be explained by anatomy. Subacromial pathology and bone quality remain the two mainproblems of shoulder surgery and pathology. That’s what had suggested to me this study about the shoulder. I was supposed to analyze glenoid bone first .The aim was to know more about arterial supply of glenoid. That was my firststudy (article 1). Then, I was interested in glenoid bone quality. And the second study had appeared. (article 2). During the shoulder dissection, I was looking for the fascia delto-trapezoidal which I didn’t found as described in books. It was my third study. (article 3). Going on I found the coraco-acromial ligament and I was surprised to see the constant portion under the acromial process. And that gave me the idea for the fourth study. (article 4).As I had discovered the very interesting technique of micro-Ct densitometry, I would like to apply it to the humeral head bone. There was the fifth study. (article 5)But, I want to know more and more about bone quality and I went on with the greater tuberosity and especially the area ofsupraspinatus insertion. The insertion and the sub-chondral bone were analyzed. There’s the last but not least study!(article 6). I was really interested in supraspinatus muscle and tendon and I want to follow the course of the muscle as the zone of conflict. I was the subject of study in life as I went through RMI . The muscle was reconstructed as finite element. Then it was possible to describe the zone of conflict with the supraspinatus. Here’s the seventh article. (article 7)

Resumo: No presente estudo, objetivou-se avaliar a utilização do enxerto alógeno de ligamento patelar (OLO) conservado em glicerina 98% e fixado por meio de parafusos de interferência como substituto do ligamento cruzado cranial (LCCr) em cães. Observou-se a exeqüibilidade e eficácia desta técnica cirúrgica e o comportamento do enxerto e dos parafusos durante o período de 120 dias, baseandose na capacidade dos exames clínicos, radiográficos e artroscópicos, em detectar o possível início e a progressão de alterações degenerativas secundárias na articulação do joelho. Para tanto foram utilizados oito animais da espécie canina pesando entre 17,2 e 26,4Kg. O enxerto utilizado correspondeu ao segmento composto pelo terço intermédio da patela, ligamento patelar e porção cranial da tuberosidade da tíbia, coletado de cadáveres de cães e conservado em glicerina 98%. Os oito cães foram separados em dois grupos, A e B e cada um contendo quatro animais para avaliação artroscópica ("segunda observação") aos 60 e 120 dias do pós-operatório. Todos os cães foram submetidos ao procedimento cirúrgico no joelho direito. Clinicamente, avaliou-se o grau de claudicação, o perímetro muscular da coxa e o movimento de gaveta cranial nos oito cães no pré-operatório e semanalmente, até completarem-se 120 dias. Foi observada diminuição da circunferência da coxa significativa (p<0,05) após o período de dez dias em que os cães permaneceram com a bandagem compressiva, sendo recuperada de forma significativa até 13° semana. As pontuações obtidas na avaliação do movimento de gaveta (extensão e flexão) tornaram-se significativamente diferentes da pré-operatória entre a 5° e 15° semanas (p<0,05). Quatro cães apresentaram ao final do experimento ausência de instabilidade articular como na avaliação pré-operatória e os outros... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this study was to evaluate the use of patelar ligament allograft (BLB) conserved in 98% glycerin and fixated with interferemce screws as a substitute of the cranial cruciate ligament in dogs (CrCL). It was observed the feasibility and efficiency of this surgical technique and the graft and screws conduct along 120 days, basing on clinical, radiographic and arthroscopic capacity in detect the beginning and progress of secondary degenerative stifle joint changes. For this purpose, eight mongrel dogs weighting from 17,2 e 26,4 Kg were used. The graft consisted of the intermediate third of the pattela, patellar ligament and cranial portion of the tibial crest, harvested from dog cadavers and preserved in 98% glycerin.The eight dogs were randomly allocated in two groups, A and B, each one with four dogs for arthroscopic evaluation ("second-look") at 60 and 120 days postoperative. All the dogs were submitted to the surgical procedure in the right knee. Clinically, lameness degree, thigh girth measurement and cranial-drawer test were evaluated in the eight dogs in preoperative, and weekly, until complete 120 days. A significant decrease in thigh girth (p<0,05) observed after ten days period that the dogs were using compressive bandage was recovered until the 13th week. The cranial-drawer test scores (flexion and extension) became significantly different between the 5th and 15th weeks postoperative (p>0,05). Four dogs presented at the final study period with no articular instability just like the preoperative evaluation, and the other four with just a slight craniocaudal instability. In the lameness evaluation, from the 4th week, all the dogs presented mean score for stands with equal... (Complete abstract click electronic access below) / Orientador: João Guilherme Padilha Filho / Coorientador: Julio Carlos Canola / Banca: Cintia Lúcia Maniscalco / Banca: Márcia Rita Fernandes Machado / Banca: Patricia Popak Giordano / Banca: Gisleine Cristina Eimantas / Doutor

Cette thèse traite de la modélisation du remodelage osseux. Nous présentons tout d'abord un modèle général continu tenant compte de la réponse cellulaire à un stimulus mécanique. Ce modèle est appliqué à des géométries 2D et 3D macroscopiques afin de se rapprocher des problématiques réelles, ainsi que sur des géométries mésoscopiques d'os trabécullaires en 2D. Cependant la complexité du remodelage osseux ne permet pas d'avoir une approche unique de modélisation. Ainsi, dans un second temps, le cas particulier du remodelage osseux orthodontique est étudié. Un nouveau modèle spécifique est développé tenant compte de l'influence du ligament parodontal sur le remodelage osseux, et intégrant l'influence du taux d'oxygène qui contrôle les évolutions de densités cellulaires. Des données expérimentales in vitro sont extraites de la littérature et servent de données d'entrées du modèle développé afin d'obtenir l'évolution de la densité osseuse alentours d'une racine dentaire cylindrique en 3D. / This work deals with modelization of bane remodeling. We present first a madel thal accounts for the cellular res panse to a mechanical stimulus in a general case at a continuous scale. This madel is applied to 2D and 3D geometries at macroscopic scale to mimic real cases, as weil as 2D trabecular-type geometries at mesoscopic scale. However, the complexity of bane remodeling does not allow a unique approach. Th us, the thesis work is focused on the particular case of orthodontie bane re mode ling. A new specifie madel is developed accounting for the influence of the periodontal ligament on orthodontie bane remodeling by integrating the oxygen concentration effect controling the evolutions of cellular densities. The cellular experimental data in vitro are extracted from the literature, and serve as input data of the developed madel in arder to ablain the evolution of bane density around the root of a 3D cylindrical tooth.

The current study investigated the distribution of periodontal epithelial cells and nerve fibres within the furcations of rat maxillary molar teeth subjected to hypothermic injury. The upper right first molars of 30 Sprague-Dawley rats were subjected to a single 20 minute application of dry ice in order to produce aseptic necrosis within the periodontal ligament, while the contralateral first molar served as an untreated control. Five animals were each sacrificed via cardiac perfusion after 7, 10, 14, 18, 21 and 28 days respectively and the maxillae were dissected out. After fixation in paraformaldehyde and processing, the tissues were embedded in paraffin wax and cut into 7µm serial coronal sections through the furcation region. Consecutive sections were then stained with H&E, cytokeratin AE1/AE3 and PGP 9.5 immunostains. Light microscopic examination of the H&E stained sections revealed that ankylosis had not developed in all of the experimental teeth, and in some of the observation groups fewer teeth were ankylosed than unaffected. The morphology of the ankylotic areas appeared to change with time, initially consisting of fine bony trabeculae, then progressing to solid bone occupying the entire furcation before becoming less solid again by the latest observation periods. Root resorption was often seen adjacent to areas of ankylosis, but the cementum of the tooth root at the point of ankylotic union was usually intact and free of resorption. Changes within the pulp chambers of the experimental teeth were also noted, with reduction in cellularity and tissue disorganisation initially, then increasing cellularity and formation of a cementum-like material on the chamber walls later. Cytokeratin AE1/AE3 immunostaining successfully identified epithelial cells within the periodontal ligament and their distribution around control teeth was similar to previous reports. Counting of these cells revealed lower numbers around experimental teeth, with the lowest counts around experimental teeth which had developed ankylosis. No change in the epithelial cell counts was detected over time, and these cells did not appear to regenerate after necrosis regardless of whether or not ankylosis developed. Statistical analysis indicated that the probability of ankylosis decreased as the number of epithelial cells increased. The PGP 9.5 immunostain identified periodontal nerve fibres, but the use of this stain was quite technique sensitive. The furcations of the molar teeth were noted to have relatively sparse innervation, with most of the visible nerve fibres being closely associated with blood vessels and located in the outer two-thirds of the ligament. Counting of the nerve fibres revealed fewer fibres around experimental teeth compared to control teeth, especially in the part of the ligament closest to the tooth root. There was no relationship detected between nerve count and time or between nerve and epithelial cell counts. Resorption was found to be more prevalent in experimental teeth, and the probability of resorption in a given tooth decreased as the epithelial cell count increased. The findings of this study suggest that the epithelial cells within the periodontal ligament have a protective function in the prevention of dentoalveolar ankylosis and resorption. Evidence of an intimate interrelationship between periodontal nerve fibre and epithelial cell numbers could not be confirmed. The null hypothesis that epithelial cell rests of Malassez do not provide a protective function against ankylosis and external root resorption was rejected, and the null hypothesis that nerve fibres and epithelial cells are not inter-dependent was retained. / http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1297409 / Thesis (D.Clin.Dent.) -- School of Dentistry, 2007

The human jaw, like all other articulated body parts, exhibits small oscillatory movements during isometric holding tasks. These movements, known as physiological tremor, arise as a consequence of the interaction of various factors. One of these factors is reflex feedback from peripheral receptors. In the human jaw, receptors that innervate the periodontium are able to transduce minute changes in force. This thesis examines the contribution of these periodontal mechanoreceptors (PMRs) to the genesis of physiological tremor of the human jaw. By using frequency domain analysis of time series recorded during isometric biting tasks, the character of physiological jaw tremor can be revealed. Physiological jaw tremor was observed in force recorded from between the teeth as well as from electromyograms recorded from the principal muscles of mastication. These recordings have shown us that jaw physiological tremor consists of a frequency invariant component between 6 and 10Hz. This frequency remains unaltered under various load conditions where the mechanical resonance of the jaw would be expected to vary greatly (Chapter 2). Such findings indicate a ‘neurogenic’ origin for this tremor. A possible candidate for this neurogenic component of physiological tremor in the jaw is the reflex feedback arising from the PMRs. Using local anaesthetisation, it has been shown in this thesis, that by blocking outflow from the PMRs, the amplitude of neurogenic physiological jaw tremor can be reduced dramatically. This procedure caused a dramatic reduction in not only the mechanical recordings of tremor but also in the coupling between masseteric muscles bilaterally (Chapter 3) and between single motor units recorded from within a homonymous muscle (Chapter 4). The obvious mechanism by which periodontal mechanoreceptor anaesthetisation could reduce the amplitude of physiological tremor in the jaw would be by reducing the amplitude of the oscillatory input to the motoneurones driving the tremor. This interpretation remains controversial however as physiological tremor in the jaw can be observed at force levels above which the PMRs are supposedly saturated in their response. In light of this knowledge, the saturating characteristics of these receptors in terms of reflex output were examined. To do this, a novel stimulation paradigm was devised whereby the incisal teeth were mechanically stimulated with identical stimulus waveforms superimposed upon increasing tooth preloads. This necessitated the use of a frequency response method to quantify the reflexes. An optimal frequency for stimulation was identified and used to confirm that the hyperbolic saturating response of PMRs observed previously, translated to a similar phenomenon in masticatory reflexes (Chapter 5). These data reinforced the idea that physiological tremor in the jaw was not just a consequence of rhythmic reflex input from PMRs, as the dynamic reflex response uncoupled from the input as the receptor-mediated reflex response saturated. An alternative hypothesis was then developed that suggested the effect of PMR suppression in physiological tremor was via tonic rather than rhythmic effects on the masseteric motoneurone pool. By utilising a novel contraction strategy to manipulate the mean firing rate of the motor neuron pool at a given level of force production, data contained in Chapter 6 shows that population motor unit firing statistics influence the expression of physiological tremor, and such manipulations mimic, to an extent, the changes in firing statistics and tremor amplitude seen during anaesthetisation of the PMRs. This thesis therefore posits a mechanism whereby periodontal input influences the firing rate of motoneurones in such a way as to promote tremulous activity (Chapter 5). However, as this proposed mechanism did not explain the full extent of tremor suppression seen during PMR anaesthetisation it can therefore only be considered a contributing factor in a multifactor process. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1297555 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2007