Memoria para optar al Título Profesional de Médico Veterinario / El óxido nítrico ( NO), producido en grandes cantidades por los ˙ condrocitos y células inflamatorias en una articulación dañada puede generar activación de enzimas degradativas de la matriz del cartílago, disminución en la síntesis de sus biomoléculas y apoptosis de condrocitos. Parte del ˙NO producido se transforma en nitrito, el cual se puede medir por la reacción de Griess. El objetivo de este estudio fue comparar el promedio de nitrito en líquido sinovial y suero sanguíneo entre grupos de equinos Fina Sangre de Carrera con cuadros articulares inflamatorios agudos y crónicos con reagudización, para establecer si la menor cantidad de cartílago articular en el caso de los cuadros crónicos se traduce en una menor concentración de nitrito tanto en LS como en suero sanguíneo. Se tomaron muestras de líquido sinovial y suero sanguíneo de equinos que cursaran con un cuadro inflamatorio agudo de la articulación carpal (n=10), principalmente fractura en chip o sinovitis diagnosticadas clínica y/o radiológicamente al momento de la toma de muestra, se incluyen equinos con diagnóstico de cuadro crónico al momento de la toma de muestra (n=15), desde la misma articulación. Además se obtuvo muestras de suero sanguíneo desde equinos normales para usarlos como control (n=10). En todas las muestras se determinó la concentración de nitrito por reacción de Griess y además se midió la concentración de proteínas como indicador del estado del animal por el método colorimétrico de Lowry et al. No se encontraron diferencias significativas en la concentración de proteínas en LS entre los grupos agudos (26,1 ± 6,2 mg/mL) y crónicos con reagudización (25,2 ± 8,1 mg/mL). Tampoco se encontraron diferencias significativas en la concentración de nitrito tanto en el LS Created with novaPDF Printer (www.novaPDF.com). Please register to remove this message. 4 entre los grupos agudo (95,1 ± 41,4 μmol/L) y crónico con reagudización (75,8 ± 21,2 μmol/L) como en el suero con valores de 471,4 ± 115,4 μmol/L para los cuadros agudos en comparación con los cuadros crónicos con reagudización (427,9 ± 101,9 μmol/L) y con los cuadros normales (455,9 ± 91,1 μmol/L). Se encontraron diferencias significativas (p<0,05) en los valores de proteínas séricas entre los grupos agudo y normal, pero a favor del grupo normal, obteniendo el grupo agudo un promedio de 56,5 ± 11,2 mg/mL, los normales 67,0 ± 3,1 mg/mL, y finalmente el grupo de los crónicos reagudizados con 60,7 ± 7,5 mg/mL. La concentración de nitrito en el líquido sinovial en los grupos agudo y crónico reagudizado no muestra diferencia significativa, lo que podría deberse a que ambos grupos están cursando un cuadro inflamatorio, que genera infiltración con células que también producen ˙NO. La ausencia de diferencia en la concentración de nitrito en el suero sanguíneo entre los grupos agudo, crónico reagudizado y normal, sugiriere que la concentración de nitrito en el suero sanguíneo no es un buen reflejo de la producción de ˙NO a nivel articular.

Esta pesquisa teve como objetivo estudar as alterações da cartilagem articular dos côndilos femural de ratos, provocadas pela variação da amplitude de movimento e da frequência, utilizando-se uma máquina de movimentação de flexo-extensão contínua passiva. Foram utilizados 24 ratos machos Wistar, divididos em quatro grupos: G1 (exercitados com 80 ciclos/minuto em grande amplitude), G2 (exercitados com 80 ciclos/minuto em pequena amplitude), G3 (exercitados com 40 ciclos/minuto em grande amplitude) e G4 (exercitados com 40 ciclos/minuto em pequena amplitude). Os animais pertencentes aos quatro grupos realizaram exercícios de flexo-extensão contínuas, diariamente, por 1 hora, através de um equipamento que atende aos princípios do mecanismo biela-manivela, o qual produz movimentos contínuos de flexo-extensão com grande e pequena amplitude, em frequência de 80 e 40 ciclos por minuto. Após 15 dias os animais foram sacrificados e de cada um a cartilagem articular do côndilo lateral do joelho direito foi retirada, incluída, cortada, corada com hematoxilina-eosina e analisada em fotomicroscópio. Pela análise histológica observou-se aumento do número de células na área da cartilagem articular definida para o estudo, nos quatro grupos exercitados, quando comparados ao respectivo controle. Os animais exercitados à velocidade de 80 ciclos por minuto e grande amplitude apresentaram um aumento no número de células quando comparados aos animais exercitados à velocidade de 40 ciclos por minuto em grande e pequena amplitude. O mesmo ocorreu com os animais exercitados com velocidade de 80 ciclos por minuto e pequena amplitude, comparados aos animais exercitados com velocidade de 40 ciclos por minuto e pequena amplitude. Quanto à análise das medidas de espessura foi encontrado aumento em todos os grupos em relação ao respectivo controle. Os animais exercitados à velocidade de 80 ciclos por minuto e grande amplitude apresentaram um aumento da medida de espessura quando comparados aos animais exercitados à velocidade de 40 ciclos por minuto e pequena amplitude, o mesmo ocorrendo com os animais exercitados com velocidade de 40 ciclos por minuto e pequena amplitude. Os dados demonstram que os exercícios de flexo-extensão contínua passiva estimulam aumento do número de células e aumento da espessura, não podendo ser atribuída como processo de lesão e, sim, como aumento de atividade metabólica e fator de proteção e adaptação. / This research had as objective to study the alterations of the articular cartilage of the knee of mices provoked by the variation of the movement width and of the frequency, using a machine of movement of passive continuous flexo-extension. 24 Wistar male mices were used, divided in four groups: G1 (exercised with 80 cycles/minute in great width), G2 (exercised with 80 cycles/minute in small width), G3 (exercised with 40 cycles/minute in great width) and G4 (exercised with 40 cycles/minute in small width). The animals belonging to the four groups accomplished flexo-extension exercises daily for 1 hour, through a equipment that assists to the principles of the \"rod-cranck\" mechanism, which produces continuous movements of flexo-extension with great width and small width in frequency of 80 and 40 cycles per minute. After 15 days the animals were sacrificed, the articular cartilage was collected, included, cut, colored with hematoxiline-eosine and analyzed in a photomicroscope. For the histologic analysis an increase of the number of cells was observed in every area of the articular cartilage in the 4 exercised groups when compared to the respective control, that the exercised animals at the speed of 80 cycles/minute and great width presented an increase in the number of cells when compared the exercised animals at the speed of 40 cycles/minute in great and small width, the same thing happening with the animals exercised with speed of 80 cycies/minute and small width, when compared to the exercised animals of 40 cycles/minute and small width. As the analysis of the measures of thickness it was found an increase in all the groups in relation to the respective control. The exercised animals at the speed of 80 cycles/minute and great width presented an increase of the measure of thickness when compared the exercised animals the speed of 40 cycles/minute and small width, the same happening with the animals exercised with speed of 40 cycles/minute and small width. The data demonstrate that the exercises of passive continuous flexo-extension stimulate an increase of the number of cells and increase of the thickness, not allowing us to attribute it as a Iesion process, but as an increase of metabolic activity as a protection and adaptation factor.

INTRODUÇÃO e OBJETIVO: A osteoartrite (OA) embora frequente tem patogênese incerta em humanos. Descrevemos modelo experimental original de OA em cães, analisando em dois tempos diferentes as consequências da Ruptura Espontânea do Ligamento Cruzado Cranial (RLCCr). MÉTODOS: Vinte animais machos com menos de 5 anos ( 20 a 45 Kg) com RLCCr submetidos à artrotomia para estabilização articular tiveram fragmentos articulares removidos para análise. O grupo RLCCr < 20 (10 animais) foi operado antes dos vinte dias e o grupo > 20 (10 animais) após 20 dias do início da lesão. Sete animais com OA pré-existente (OA) que morreram por quaisquer motivos e 7 animais normais (NC) provenientes do C.C.Z., serviram de grupos controles. Os animais foram avaliados clinica e radiologicamente. Foi colhido líquido sinovial dos animais operados e de outros 20 cães controles submetidos às cirurgias por diferentes causas. Para estudo morfológico, os fragmentos de cartilagens foram corados com H&E e Picrossirius. A gravidade do escore histológico da OA foi quantificada através da coloração com Safranina O. Analisou-se citocinas próinflamatórias (IL-6, TNF-alfa) e a quimiocina CCL2/MCP-1 nos líquidos sinoviais. RESULTADOS: Todos os cães tinham o teste de movimento da gaveta e exame de compressão da mesa tibial positivos. Achados radiográficos correlacionaram-se com maior tempo de RLCCr. Cartilagem articular de animais normais (NC) exibiram superfície preservada, disposição ordenada dos condrócitos e integridade da rede de colágeno. Exames histológicos em animais do grupo RLCCr < 20 mostraram irregularidades na superfície articular, diminuição no número de condrócitos e remodelamento de fibras de colágeno. No grupo > 20, observou-se osteófitos e irregularidades evidentes nas superfícies articulares. A gravidade do escore de acometimento histológico traduziu-se por intensa diminuição celular na superfície articular, com presença de clusters de condrócitos na região intermediária da cartilagem e total desorganização da rede de fibras de colágeno. A quimiocina CCL2/MCP-1 esteve aumentada no grupo com menos de 20 dias de lesão, enquanto a IL-6 foi mais expressiva nos animais operados tardiamente. CONCLUSÃO: O modelo experimental espontâneo de OA canino, estudado em dois tempos, é um instrumento original e útil para estudo da patogênese da osteoartrite, além de ter o mérito de preservar a integridade física dos animais de laboratório / INTRODUCTION and OBJECTIVE: Osteoarthritis (OA) is a frequent and severe rheumatic disease of unknown pathogenesis. We described an original experimental model of OA, analyzing the consequences of spontaneous cranial cruciate ligament rupture (RLCCr), occurred at two different times. METHOD: Twenty male animals, younger than 5 years old (20 to 45kg) with RLCCr were submitted to arthrotomy for articular stability and had cartilage fragments removed for analysis. The Group RLCCR < 20 (10 animals) was operated before 20 days and Group RLCCR > 20 (10 animals) after 20 days of beginning of lesion. Seven animals with pre-existent OA which died without any reason, and 7 normal animals (NC) from Service of Zoonosis Control were the control groups. The animals were submitted to clinical and radiological evaluations. Synovial fluid were collected from operated dogs and from another 20 control animals, submitted for surgical procedures for any reason. For the morphological study, the cartilage fragments were stained with H&E and Picrossirus. The score for OA severity was quantified using Safranin-O staining. Inflammatory cytokines (IL-6 and TNF alfa) and chemiokine CCL2/MCP-1 were measured in sinovial fluid. RESULTS: At physical examination, all the dogs had positive drawer and the tibial plateau compression tests. Knee Radiographic data showed that narrowing of joint space, osteophytes and erosions were more prominent in Group RLCCr> 20 animals. Articular cartilage of normal animals (NC) revealed preserved cartilage surface, organized disposition of chondrocytes and integrity of collagen net. Histological exams done in animals from Group RLLCr > 20 showed irregularities on articular surface, reduction of the number of chondrocytes and collagen fibers remodeling. Animals from Group RLCCR > 20 exhibited deep fibrillations, presence of chondrocytes clusters at intermediate area of cartilage, osteophytes and and total disorganization of the collagen fibers net. Chemiokine CCL2/MCP-1 was found overexpressed in dogs operated less than 20 days, while IL-6 was increased in late surgical group. CONCLUSION: The spontaneous model of canine RLCCr, studied at two distinct times, is an original and useful tool to understand pathogenesis of OA. Furthermore, the procedure preserves the animal integrity, becoming an Ethical laboratorial procedure

Objetivo: Determinar la asociación entre el tiempo de uso de Smartphone y los rangos de movimiento cervical. Metodología: Estudio transversal analítico en estudiantes universitarios de ambos sexos de una universidad de Lima Metropolitana durante el año 2017. Se excluyeron a personas que reportaron tener disfunciones cervicales o usar collarín. Se utilizó un cuestionario con preguntas sobre datos demográficos, posesión de Smartphone, tiempo de uso total y por actividades. Se midieron rangos de los 6 movimientos del cuello (flexión, extensión, inclinaciones y rotaciones a ambos lados) mediante el uso de un goniómetro universal. Resultados: Se analizaron a 233 encuestados (72,1% mujeres) con una mediana de uso de Smartphone de 332 minutos al día. Los promedios para los rangos de movimiento de cuello fueron: Flexión 48,6°±11,0; extensión 45,3°±11,5; rotación derecha 67,6°±11,1 e izquierda 68,6°±9,5; y lateralización derecha 29,1°±8,3 e izquierda 26,5°±8,4. En el análisis de regresión no se encontró asociación entre el tiempo total de uso de Smartphone y rangos de movimiento de cuello (p>0,05). Se encontró asociación entre el tiempo de uso del Smartphone para aplicaciones de chat y el movimiento de flexión (β=-0,010; p=0,035) y el movimiento de lateralización derecha (β=-0,008; p=0,020); y el movimiento de rotación derecha y juegos (β=-0,041; p=0,026). Conclusiones: No hubo asociación entre el tiempo total de uso de Smartphone y los rangos de movimiento cervical. El movimiento de flexión con las actividades de chat (p=0,035), rotación derecha con juegos (p=0,026) y lateralización izquierda con aplicaciones de chat (p=0,020) si demostraron asociación. / Objective: To determine the association between smartphone usage time and cervical ranges of motion (cROM). Methods: An observational analytical cross-sectional study on university students of both genders, located at a university in Lima during the year 2017. We used a questionnaire to gather demographic data, cell phone possession, total time of smartphone usage and by smartphone activities (calls, sms message, chat applications, social network applications, internet browsing and games), presence of neck dysfunction, and the use of a collar. Cervical ROM (flexion, extension, lateralization and rotation of both sides) was measured with a universal goniometer after the questionnaire. Results: 233 students (72.1% females) were analyzed with an average smartphone use of 332 minutes per day. The average range of motion was 48,6°±11,0 for flexion; 45,3°±11,5 for extension; 67,6°±11,1 for right rotation; 68,6°±9,5 for left rotation; 29,1°±8,3 for right lateralization and 26,5°±8,4 for left lateralization. Regression analysis shows negative association with cervical flexion and chat applications (β=-0.010 p=0.035), right lateralization with chat applications (β=-0.008, p=0.020) and right rotation with games (β=-0.041, p=0.026). No correlation was found between total usage of smartphone and cervical range of motion. Conclusions: There was no correlation between smartphone usage time and cervical ranges of motion (cROM). Activities like chat applications had a negative influence in flexion (p=0,035) and left lateralization (p=0,020); while games had the same effect in right rotation (p=0,026). / Tesis

Made available in DSpace on 2019-03-30T00:22:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-06-30 / In this work is presented a development of a hybrid solution (software and hardware) integrating the computer and the Kinect sensor. The proposed solution, here called GoNet v2, is an instrument for the dynamic and automatic evaluation of biomechanical rehabilitation processes. Experimental tests for the evaluation of the range of motion of patients, especially for elbow flexion, elbow extension, shoulder abduction, shoulder flexion, radial deviation and ulnar deviation, are presented and discussed. We also presented the exergamers for rehabilitation tests, based on Kabat diagonal and squatting. Ten healthy individuals were evaluated using GoNet v2 and the universal goniometer and twelve professionals were submitted to an evaluation of the instrument, answering a survey. The intraclass correlation coefficient (ICC) was used to analyze the reproducibility, and for the analysis of accuracy the errors were compared in the worst cases in the mean and compared to the maximum amplitude of each movement. Regarding intra-examiner and inter-examiner reproducibility, high ICC values were found for the range of flexion / extension of the shoulder, abduction of the shoulder and ulnar deviation, thus showing its optimum precision. When evaluated by specialists, the comparison between goniometry and GoNet v2, the proposed instrument showed significant results when the amplitudes of flexion / extension of shoulder (3.61%) and elbow (3.17%) and abduction (2.11%) of the shoulder were observed. Based on the results found, GoNet v2 proved to have high reproducibility, except for radial deviation. Regarding accuracy, we found relevant results in measurements of abduction of the shoulder and flexion / extension of the elbow and shoulder. Keywords: Arthrometry; Biomechanical rehabilitation; Exergames; Kinect sensor; Dynamic evaluation; Goniometry. / Neste trabalho é apresentado o desenvolvimento de uma solução hibrida (software e hardware) integrando o computador e o sensor Kinect. A solução proposta, aqui chamado GoNet v2, é um instrumento para a avaliação dinâmica e automática de processos de reabilitação biomecânicas. Testes experimentais para a avaliação da amplitude de movimento de pacientes, especialmente para flexão do cotovelo, extensão do cotovelo, abdução de ombro, flexão de ombro, desvio radial e desvio ulnar, são apresentados e discutidos. Foram apresentados também os testes dos exergames para reabilitação, baseados na diagonal de Kabat e no agachamento. Dez indivíduos saudáveis foram avaliados utilizando o GoNet v2 e o goniômetro universal e doze profissionais foram submetidos a uma avaliação do instrumento através do preenchimento de um questionário O coeficiente de correlação intraclasse (CCI) foi utilizado para analisar a reprodutibilidade, e para a análise da exatidão foram comparados os erros nos piores casos na média e comparada a amplitude máxima de cada movimento. Quanto à reprodutibilidade intraexaminadores e interexaminadores, altos valores de CCI foram encontrados para a amplitude de movimento de flexo / extensão de ombro, abdução de ombro e desvio ulnar, mostrando assim sua ótima precisão. Quando avaliados por especialistas, a comparação entre a goniometria e o GoNet v2, o instrumento proposto mostrou resultados significativos quando observados as amplitudes de flexo/extensão de ombro(3.61%) e cotovelo (3,17%) e abdução de ombro (2,11%). Com base nos resultados encontrados, GoNet v2 provou ter alta reprodutibilidade, exceto para desvio radial. Em relação à exatidão foram encontrados resultados relevantes nas medições de abdução de ombro e flexo/extensão do cotovelo e ombro. Palavras-chave: : Artrometria Articular; Reabilitação Mecânica; Exergames; Sensor Kinect; Avaliação Dinâmica; Goniometria; GoNet v2

Articular cartilage is a mechanically important soft tissue whose organisation at the micro- and nanoscale is critical for healthy joint function and where degeneration is associated with widespread disorders such as osteoarthritis. The tissue possesses a complex, graded and depth-dependent structure and at the nanoscale, cartilage mechanical functionality is dependent on the collagen and hydrated proteoglycans that form the extracellular matrix. The structure and in situ dynamic response of the collagen fibrils at the nanoscale, however, remain unclear. Here we utilise small angle X-ray diffraction to measure the depth-wise structure of the fibrillar architecture whilst performing time-resolved measurements during compression of bovine and human cartilage explants. We demonstrate the existence of a depth-dependent fibrillar pre-strain as determined by the D-periodicity, estimated at approximately 1-2%, due to osmotic swelling pressure from the proteoglycans. Furthermore, we reveal a rapid reduction and recovery of this pre-strain during stress relaxation, approximately 60 seconds after onset of peak load. Selective proteoglycan removal disrupts both collagen fibril pre-strain and transient responses during stress relaxation. Additionally, we show that IL-1β induced tissue inflammation also results in a reduction in fibrillar pre-strain and altered fibrillar mechanics. Cyclic loading induces a dynamic reduction and recovery in the D-period that is present regardless of loading rate or treatment, along with changes in diffraction peak intensities and widths. These findings suggest that the fibrils respond to loading via intra- and inter-fibrillar disordering alongside a transient response that is mediated by changes in hydration. These are the first studies to highlight previously unknown transient and cyclic responses to loading at the fibrillar level, and are likely to transform our understanding of the role of collagen fibril nano-mechanics in cartilage and other hydrated soft tissues. These methods can now be used to better understand cartilage in aging and other muscoskeletal diseases.

Cheung Wing-hoi. / "December 1999." / Thesis (Ph.D.)--Chinese University of Hong Kong, 1999. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

The articular cartilage has a limited capacity to regenerate. Cartilage lesions often result in degeneration, leading to osteoarthritis. Current treatments are mostly palliative and reparative, and fail to restore cartilage function in the long term due to the replacement of hyaline cartilage with fibrocartilage. Although a stem-cell based approach towards regenerating the articular cartilage is attractive, cartilage generated from human mesenchymal stem cells (hMSCs) often lack the function, organization and stability of the native cartilage. Thus, there is a need to develop effective methods to engineer physiologic cartilage tissues from hMSCs in vitro and assess their outcomes in vivo. This dissertation focused on three coordinated aims: establish a simple in vivo model for studying the maturation of osteochondral tissues by showing that subcutaneous implantation in a mouse recapitulates native endochondral ossification (Aim 1), (ii) develop a robust method for engineering physiologic cartilage discs from self-assembling hMSCs (Aim 2), and (iii) improve the organization and stability of cartilage discs by implementing spatiotemporal control during induction in vitro (Aim 3). First, the usefulness of subcutaneous implantation in mice for studying the development and maintenance of osteochondral tissues in vivo was determined. By studying juvenile bovine osteochondral tissues, similarities in the profiles of endochondral ossification between the native and ectopic processes were observed. Next, the effects of extracellular matrix (ECM) coating and culture regimen on cartilage formation from self-assembling hMSCs were investigated. Membrane ECM coating and seeding density were important determinants of cartilage disc formation. Cartilage discs were functional and stratified, resembling the native articular cartilage. Comparing cartilage discs and pellets, compositional and organizational differences were identified in vitro and in vivo. Prolonged chondrogenic induction in vitro did not prevent, but expedited endochondral ossification of the discs in vivo. Finally, spatiotemporal regulation during induction of self-assembling hMSCs promoted the formation of functional, organized and stable hyaline cartilage discs. Selective induction regimens in dual compartment culture enabled the maintenance of hyaline cartilage and potentiated deep zone mineralization. Cartilage grown under spatiotemporal regulation retained zonal organization without loss of cartilage markers expression in vivo. Instead, cartilage discs grown under isotropic induction underwent extensive endochondral ossification. Together, the methods established in this dissertation for investigating cartilage maturation in vivo and directing hMSCs towards generating physiologic cartilage in vitro form a basis for guiding the development of new treatment modalities for osteochondral defects.

There are limited treatment options available today to slow down progression of osteoarthritis in its early stages and most interventions, such as highly invasive partial and total joint replacement surgeries, are performed only at the late stages of the disease. Understanding the mechanism of early articular cartilage stress-mediated wear and failure can aid in the design of new treatment options that are introduced at earlier stages of the disease, presenting the potential to slow down osteoarthritis progression and thus significantly improve patient outcomes. This dissertation aims to provide a basic science understanding of wear propagation and repair of articular cartilage in the absence of traumatic events under the normal reciprocal sliding motion of the articular layers at physiologic load magnitudes. In this dissertation there are three main thrusts: (1) characterize cartilage delamination wear under normal sliding (2) define a chemical environment that promotes cartilage explant homeostasis to enable long-term wear-and-repair studies (3) investigate a practical treatment modality capable of stopping or slowing down structural degeneration of articular cartilage in OA. We hypothesize that the mode of cartilage damage is delamination wear that progresses by fatigue failure of the extracellular matrix (ECM) under physiologic sliding, even when cartilage layers are subject to physiologic load magnitudes and contact stresses and even when the friction coefficient μ remains low (H1a). Based on prior literature findings regarding the role of synovial fluid (SF) boundary lubricants on the reduction of friction and wear, we also test the hypothesis (H1b) that SF delays the onset of cartilage delamination when compared to physiological buffered saline (PBS). We then test a third hypothesis (H1c) that loading cartilage against cartilage delays the onset of delamination wear compared to testing glass on cartilage, since contacting porous cartilage layers exhibit a much smaller solid-on-solid contact area fraction than impermeable glass contacting porous cartilage. Next, we hypothesize that the homeostatic dysregulation previously observed in cultured immature cartilage explants results from the presence of non-physiologic levels of important metabolic mediators in the culture medium. To this end, we hypothesize that: (H2a) immature bovine cartilage explants cultured in native synovial fluid will maintain homeostasis as characterized by maintenance of their mechanical properties and ECM contents at initial (post- explantation) levels, and (H2b) explants cultured in a physiologic-based medium, consisting of physiologic levels of key metabolic mediators, will maintain a similar homeostasis over long- term culture. Finally, a laser treatment strategy is explored that has the capability to reform collagen crosslinks, replacing those lost during OA progression. This novel therapy acts without injuring the cells and without any chemical additive or thermal ablation. The laser treatment protocol used in this application can specifically target the subsurface region, located 200 μm of the articular surface. By strengthening this region with enhanced crosslinking, we hypothesize (H3a) that cartilage will demonstrate greater resistance to fatigue failure than untreated controls. We then hypothesized (H3b) that this treatment protocol would also be effective on devitalized fibrillated human articular cartilage from OA joints with overall Outerbridge score OS1-3. We find that for both cartilage-on-cartilage and glass-on-cartilage sliding configurations at physiologic applied loads, long-term sliding with a low friction coefficient causes wear in the form of delamination. We show that the use of synovial fluid as a lubricant delays the onset of wear; and, similarly, that sliding with a cartilage counterface also reduces the incidence of wear. In subsequent studies we fully characterize a homeostatic culture medium to emulate cartilage in vitro behavior in synovial fluid. We show that explants cultured in this medium can maintain their properties for at least one month and have no loss in cell viability. Laser treatment is then tested on both living and devitalized bovine and devitalized human cartilage and the treatment is shown to improve the wear resistance of the tissue without harming embedded cells. Overall this work has led to novel insights that have clinical applicability. One strength of the in vitro investigations described in this body of work is the ability to separate out mechanically-mediated events from biochemically-mediated events, which would be impossible in vivo. Parsing out such specific mechanisms of cartilage wear can help guide better understanding of disease progression and drive therapeutic intervention. Intervening during the early stages of OA offers the promise of preventive care that currently does not exist and could provide significant benefits to a patient’s quality of life. This dissertation asserts that focusing on delaying or preventing wear by improving the resiliency of the extant intact cartilage in early OA is a viable strategy to improve patient outcomes and offers an innovative approach over existing regenerative techniques.

by Choi Man. / Year shown on spine: 1997. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 146-153). / Abstract --- p.1 / Chapter 1 --- Introduction --- p.3 / Chapter 1.1 --- Anatomy --- p.4 / Chapter 1.2 --- Kinematics of the overhead sports --- p.6 / Chapter 1.3 --- Isokinetics assessment of the shoulder rotators --- p.8 / Chapter 1.4 --- Objectives of the study --- p.10 / Chapter 1.5 --- Method of investigation --- p.11 / Chapter 1.5.1 --- Subject --- p.12 / Chapter 1.5.2 --- Equipment --- p.13 / Chapter 1.5.3 --- Protocol --- p.14 / Chapter 1.6 --- Data Management --- p.17 / Chapter 1.7 --- Clinical application --- p.18 / Chapter 1.8 --- Definition of terms --- p.18 / Chapter 2 --- Literture Review --- p.20 / Chapter 2.1 --- Anatomy --- p.20 / Chapter 2.1.1 --- Ligament --- p.21 / Chapter 2.1.2 --- Muscles --- p.24 / Chapter 2.2 --- Biomechanics of the overhead movement --- p.30 / Chapter 2.2.1 --- Wind up Phase --- p.32 / Chapter 2.2.2 --- Cocking Phase --- p.33 / Chapter 2.2.3 --- Acceleration Phase --- p.36 / Chapter 2.2.4 --- Deceleration Phase --- p.38 / Chapter 2.3 --- Eccentric contraction --- p.40 / Chapter 2.3.1 --- Physiology of eccentric contraction --- p.40 / Chapter 2.3.2 --- Mechanical trauma in eccentric contraction & DOMS --- p.41 / Chapter 2.3.3 --- Eccentric contraction in Plyometric --- p.43 / Chapter 2.3.4 --- Role of eccentric contraction in overhead sports --- p.44 / Chapter 2.3.5 --- Comparison with concentric contraction --- p.45 / Chapter 2.4 --- Isokinetics --- p.46 / Chapter 2.4.1 --- Introduction to isokinetics --- p.46 / Chapter 2.4.2 --- Reliability of isokinetic assessment on Shoulder rotator --- p.48 / Chapter 2.4.3 --- Agonist / Antagonist Ratio --- p.51 / Chapter 2.4.4 --- Variation of torques with testing protocols --- p.52 / Chapter 2.4.5 --- Comparison of muscle torques in different groups --- p.56 / Chapter 2.4.6 --- Isokinetic eccentric contraction of shoulder Rotators --- p.62 / Chapter 3 --- Method of Investigation --- p.63 / Chapter 3.1 --- Subject --- p.64 / Chapter 3.1.1 --- Part One --- p.64 / Chapter 3.1.2 --- Part Two --- p.65 / Chapter 3.1.3 --- Criteria of subject recruitment --- p.65 / Chapter 3.2 --- Equipment --- p.66 / Chapter 3.2.1 --- Collection of medical history and general informations --- p.66 / Chapter 3.2.2 --- Test for general laxity --- p.66 / Chapter 3.2.3 --- Test for shoulder impingement --- p.72 / Chapter 3.2.4 --- Test for shoulder instability --- p.73 / Chapter 3.2.5 --- Joint range measurement --- p.76 / Chapter 3.2.6 --- Isokinetic strength of shoulder rotators --- p.78 / Chapter 3.3 --- Calibration --- p.79 / Chapter 3.4 --- Testing procedure --- p.79 / Chapter 3.4.1 --- "Explanation,warning & consent" --- p.79 / Chapter 3.4.2 --- Warming up --- p.80 / Chapter 3.4.3 --- Screening --- p.81 / Chapter 3.4.4 --- Isokinetic testing of the rotational strength of both shoulders --- p.81 / Chapter 3.5 --- Operator --- p.87 / Chapter 3.6 --- Data Management --- p.88 / Chapter 3.6.1 --- Part One --- p.88 / Chapter 3.6.2 --- Part Two --- p.89 / Chapter 4 --- Result --- p.91 / Chapter 4.1 --- Part One --- p.89 / Chapter 4.1.1 --- Intra-class correlation coefficient --- p.90 / Chapter 4.1.2 --- Correlation between the PTR & the ASMSTR --- p.92 / Chapter 4.2 --- Part Two --- p.94 / Chapter 4.2.1 --- Comparison between the Members in the Hong Kong Badminton Team with the Non-athlete Subjects --- p.94 / Chapter 4.2.2 --- Comparison between the Badminton Players in the Hong Kong Team and the Hong Kong National Junior Team --- p.105 / Chapter 5 --- Discussion --- p.111 / Chapter 5.1 --- General discussion of the design of the study --- p.111 / Chapter 5.1.1 --- Subject --- p.111 / Chapter 5.1.2 --- Specific test --- p.112 / Chapter 5.1.3 --- Warming up --- p.112 / Chapter 5.1.4 --- Testing protocol --- p.113 / Chapter 5.2 --- Part One --- p.116 / Chapter 5.2.1 --- Test-retest reliability --- p.117 / Chapter 5.2.2 --- Correlation between the PTR and the ASMSTR --- p.120 / Chapter 5.3 --- Part two --- p.122 / Chapter 5.3.1 --- Comparison between the HKT and the non- athletes --- p.123 / Chapter 5.3.2 --- Presentation of torque ratio in the HKJ --- p.133 / Chapter 5.3.3 --- Performance in those with history of shoulder problem --- p.134 / Chapter 5.4 --- Clinical application and suggestion for further study --- p.139 / Chapter 6 --- Conclusion --- p.144 / Chapter 7 --- Reference --- p.146 / Chapter 8 --- Appendix