Abstract The purposes of the present research were to compare the outcome after Achilles tendon rupture repair in two postoperative regimens, to compare Achilles tendon elongation in two postoperative treatment methods, to compare the effects of two postoperative methods on motor performance aspects such as simple reaction time, choice reaction time, speed of movement, foot tapping speed and coordination, to test the mechanical properties of the recently developed poly-L/D-lactide (PLDLA) sutures and Maxon® sutures when implanted in the Achilles tendons of rabbits, and to study the histological tissue reactions and biodegradation of these sutures under the same conditions. Isokinetic calf muscle strength scores at the last control check-up were excellent in 56% of the patients in the early motion group, good in 32%, fair in 8%, and poor in 4%, whereas the scores in the cast group were excellent in 29% of cases, good in 50% and fair in 21%. The ankle performance scores were excellent or good in 88% of the patients in the early motion group, fair in 4% and poor in 8%, whereas the scores in the cast group were excellent or good in 92% of cases and fair in 8%. No significant differences were seen between the two groups at 3 months and at the last control checkups with regard to pain, stiffness, subjective calf muscle weakness, footwear restrictions, range of ankle motion, isokinetic calf muscle strength or overall outcome. The complications included 1 re-rupture in the early motion group and 1 deep infection and 2 re-ruptures in the cast group. AT elongation occurred in both groups, but was somewhat less marked in the early motion group. The AT elongation curves rose at first and then fell slowly in both groups. The patients who had less AT elongation achieved a better clinical outcome. AT elongation did not correlate significantly with age, body mass index or isokinetic peak torques. The recovery of motor performance functions such as simple reaction time, choice reaction time, speed of movement, foot tapping speed and coordination did not depend on the two postoperative regimens. The motor functions of the operated leg had obviously recovered to the level of the non-operated leg 12 weeks after the operation. Sutures made of PLDLA were used successfully for Achilles tendon repair in rabbits. There was no significant difference between the in vitro and in vivo tensile strength retention of the sutures. By comparison with Maxon®, PLDLA was found to have a lower initial tensile strength but more prolonged strength retention. The breaking strength values of the Achilles tendons repaired with sutures of these types were not significantly different at 6 weeks. Intratendinous PLDLA sutures formed a thinner fibrous capsule during the 12-week follow-up period than did Maxon® sutures of the same diameter. The suture materials had not been totally absorbed by 12 weeks.

No description available.

Le Laboratoire Biométiss oeuvre dans le domaine de la mécanobiologie. Ses recherches visent à mieux comprendre l’évolution des propriétés viscoélastiques in vitro des tissus conjonctifs mous vivants sous chargement mécanique. L’outil premier de ce type de recherche in vitro se nomme bioréacteur. Il permet la mimique des sollicitations mécano-biochimiques physiologiques ou traumatiques auxquelles sont soumis les tissus in vivo ainsi que la caractérisation destructive ou non-destructive de leurs propriétés viscoélastiques. En 2007, un premier bioréacteur destiné à la stimulation et la caractérisation in vitro à long terme de tendons de queue de rat a été conçu et fabriqué par un membre de Biométiss (Huppé, 2007). L’expérience acquise avec celui-ci a permis d’acquérir une meilleure définition des besoins du laboratoire. Elle a aussi permis d’identifier certaines limitations principalement associées à la convivialité ainsi qu’à la qualité de mesure et de contrôle de ce premier bioréacteur. Il a alors été convenu que la conception d’un nouveau bioréacteur était nécessaire et préférable à la modification du premier bioréacteur. C’est ainsi qu’a pris naissance le projet de maîtrise portant sur la conception d'un bioréacteur de haute performance permettant la stimulation et la caractérisation mécanique à long terme des tendons de queue de rat. L’approche de conception inspirée des machines de haute précision et adoptée pour concevoir le bioréacteur a permis d’avoir un regard nouveau sur le bioréacteur et mettre en oeuvre plusieurs innovations importantes. Les concepts novateurs de servo-actionneur personnalisé, d’isolation vibratoire à deux niveaux ou de labyrinthe mobile, pour n’en nommer que quelques-uns, ont permis d’atteindre de hautes performances. Les fruits de ces innovations sont entre autres : - L’amélioration de la qualité de mesure et de contrôle résultant de la stimulation et de la caractérisation mécanique; - L’optimisation de la convivialité d’utilisation; - La minimisation du facteur humain sur les résultats. Finalement, l’article intitulé A Roadmap for the Design of Bioreactors in Mechanobiological Research and Engineering of Load-Bearing Tissues par Viens et al. (2011) a été rédigé à partir de l’expérience de conception vécue dans le cadre du présent projet. Il propose une approche structurée, basée sur l’analyse du cycle d’utilisation du bioréacteur et de la routine de stimulation et de caractérisation mécanique, permettant d’élaborer un cahier des charges fonctionnelles complet et exact. Il est espéré que cet article permettra de guider le chercheur à travers cette étape décisive et ardue du processus de conception d’un bioréacteur.

No description available.

No description available.

Tendon, ligament, and joint capsular injuries represent 45% of the 32 million musculoskeletal injuries each year in the United States. Tendon injuries are especially common, requiring surgical repair for the shoulder’s rotator cuff tendons (51,000 per year), the Achilles tendon (44,000 per year), and the patellar tendon (42,000 per year). Tissue engineering provides an alternative in the treatment of tendon lesions through replacement of an injured tendon segment. The purpose of this study was to develop a tendon construct in vitro for clinical reconstructive surgery. Human tenocytes were isolated from hamstring tendons of patients who had undergone anterior cruciate ligament (ACL) surgeries. These tenocytes were cultured with culture media (α-MEM) supplemented with various concentrations of foetal bovine serum (FBS) (0%, 1%, 5% and 10%) and in the presence of different growth factors such as PDGFBB (0, 5, 10 and 50ng/ml), basic FGF (0, 5, 10 and 50ng/ml), IGF-1 (0, 10 and 50ng/ml) and TGFβ-3 (0, 1 and 10ng/ml). Fractional factorial design was utilized to select the combinations of growth factors that supported the following criteria: (1) the maximal cell proliferation with a minimum differentiation of the tenocytes in the presence of the least concentration of FBS possible and (2) maintaining cell survival and promoting tenocyte differentiation in FBS free culture media. The results have shown that: (i) The tenocyte cell number when cultured for 14 days in media supplemented with 1% FBS, 50ng/ml PDGFBB and 50ng/ml bFGF matched that of the positive control (10% FBS-treated cells). Not only was the collagen synthesis significantly reduced in these growth factor-treated cultures compared to positive control tenocytes, but also a significant inhibition of the mRNA expression of various tenocyte differentiation markers (Scleraxis, Tenomodulin, Collagen type I and Decorin) was evident. IGF-1 did not promote significant cell proliferation under low serum conditions but did induce tenocyte differentiation in vitro. Examination of the cell morphology confirmed that tenocytes were capable of less differentiation when cultured with 1% FBS, 50ng/ml PDGFBB and 50ng/ml bFGF, this culture condition was termed “the expansion phase”; (ii) The cell survival was maintained for up to 14 days in serum free culture media supplemented with 50ng/ml IGF-1 and 10ng/ml TGFβ-3 whilst cell differentiation was enhanced and evident by the increase in collagen synthesis and cell morphology. Furthermore, mRNA expression of the aforementioned cell differentiation markers were also significantly increased, this culture condition was termed “the differentiation phase”; (iii) By combining the culture condition optimized for the expansion and differentiation phase sequentially, it was possible to maintain a long term 2-D tenocyte culture in vitro for up to 28 days. In these cultures, the presence of dense collagen formation was clearly evident whereas in positive control group (10% FBS group) such observation was not noted even after prolonged culturing period of up to 45 days. These results suggested that the sequential treatment of tenocytes with growth factors identified for the expansion and differentiation phases was significantly more superior than the standard 10% FBS treatment; (iv) By combining the expansion and differentiation phases optimized for the 2-D cultures, it was possible to maintain human tenocytes in a 3-D scaffold (Bombix silk) for up to 28 days. The tendon like constructs that were formed, macroscopically and microscopically resembled the human hamstring tendon. This observation was confirmed by using H&E staining, scanning electron microscopy and by detecting collagen type I immunohistochemically; (v) It was possible to further validate these findings using in vivo animal models. This was undertaken by implanting the tenocytes cultured sequentially in the defined culture media described above, into the quadriceps of Balb/c nude male mice for up to 30 days. The nature and specificity of the tendon like structure that was formed after this implantation was investigated by H&E staining and immunohistochemistry. It was revealed that the culture conditions that were optimized during the expansion and differentiation phases were suitable for generating a human tendon reconstruct; a finding which is of significance due to its potential for tendon reconstructive surgery.

A utilização do ultra som com a finalidade de acelerar o reparo tecidual é muito freqüente na prática clínica, embora as bases científicas para sua utilização não estejam bem estabelecidas. Este estudo analisou os efeitos do ultra som na cicatrização de tendões flexores de coelhos após tenorrafia. Foram utilizados 30 coelhos da raça Nova Zelândia, com peso médio de 2,7 Kg, divididos em dois grupos de 15 animais submetidos a tenotomia e tenorrafia com sutura tipo Kessler do tendão flexor profundo do terceiro dedo da pata dianteira direita. Após 24 horas foi iniciado em um dos grupos tratamento com ultra som, sendo o outro grupo utilizado para controle. A freqüência utilizada foi a de 3 MHz e a intensidade de 0,8 W/centímetro quadrado (SATA), por contato direto durante 7 dias consecutivos. Cada grupo foi dividido em subgrupos com 5 animais cada, e estes sacrificados em períodos distintos (8, 15 e 30 graus PO), e o tendão operado, dissecado e submetido à análise histológica pela microscopia de luz, analisando a reação inflamatória, grau de necrose, proliferação de fibroblastos, deposição de colágeno e formação de granuloma. Os resultados mostraram que o ultra som interferiu com o processo de reparo tecidual após a tenorrafia dos tendões flexores de coelhos / The use of ultrasound aiming to accelerate tissue healing is very frequent in clinical pratice, although the scientific basis to its use are not well established. This study analized the effects of ultrasound on the healing of rabbit’s flexor tendons after repair. It was used 30 New Zealand rabbits, with an average weight of 2.7 Kg, divided in two groups of 15 animal. They were submetted to tenotomy and repair with Kessler’s suture on deep flexor tendon of the middle right front claw. After 24 hour one of the groups started the ultrasound treatment, and the other was de control group. The ultrasound frequency used was 3 MHz and the intensity was 0.8 W/square cemtimeter (SATA), by direct contact during 7 consecutive days. Each group was divided in subgroups with 5 animals each, and these were killed in distincts periods (PO 8, 15 and 30), and the operated tendon was dissected and submitted to histologic analises by light microscopy, anlaysing the inflammatory reaction, necrosis degree, fibroblasts proliferation, colagen synthesis and granulom formation. The result showed that ultrasound interfere on the tissue healing process after repair on the rabbit’s flexor tendons

by Lee Wai Chi, Edwin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 115-125). / Acknowledgments --- p.I / List of figures --- p.II / List of tables --- p.III / List of graphs --- p.III / Abstract --- p.VIII / Chapter I.CHAPTER ONE --- Introduction --- p.1 / Chapter 1.1 --- Electromagnetic / Magnetic field in biological interventions --- p.1 / Chapter 1.2 --- Objective of the study --- p.4 / Chapter 1.3 --- Hypothesis of the study --- p.5 / Chapter II.CHAPTER TWO --- Literature Review --- p.6 / Chapter 2.1 --- Inflammation / Chapter 2.1.1 --- Models of studying tendon injuries --- p.6 / Chapter 2.1.2 --- Methods of measuring inflammation --- p.7 / Chapter 2.1.3 --- Treatments of soft tissue inflammation --- p.9 / Chapter 2.2 --- Aspects of electromagnetic and magnetic fields / Chapter 2.2.1 --- Applications of electromagnetic / magnetic fields in soft tissue inflammation --- p.12 / Chapter 2.2.2 --- Physiological effects of electromagnetic/magnetic fields / Chapter 2.2.2.1 --- Experiments on inflammation --- p.16 / Chapter 2.2.2.2 --- Experiments on soft tissue / tendon injuries --- p.16 / Chapter 2.2.2.3 --- Experiments on blood circulation --- p.18 / Chapter 2.2.3 --- Experiments with different parameter settings of PEMF / PMF in soft tissue inflammation --- p.19 / Chapter 2.2.4 --- Proposed mechanisms of electromagnetic/magnetic fields --- p.22 / Chapter III.CHAPTER THREE --- Methods and Materials --- p.23 / Chapter 3.1 --- Animal models --- p.23 / Chapter 3.2 --- Apparatus --- p.24 / Chapter 3.3 --- Treatment Regimen --- p.27 / Chapter 3.4 --- Assessments --- p.29 / Chapter IV.CHAPTER FOUR --- Histological Assessment --- p.30 / Chapter 4.1 --- Introduction --- p.30 / Chapter 4.2 --- Methods --- p.31 / Chapter 4.3 --- Results --- p.31 / Chapter 4.4 --- Discussions --- p.45 / Chapter V.CHAPTER FIVE --- Morphometrical analysis on tissue sections with immunochemical staining --- p.51 / Chapter 5.1 --- Introduction / Chapter 5.1.1 --- Different approaches in identification of macrophages --- p.51 / Chapter 5.1.2 --- Avidin-biotin enzyme complex assay --- p.52 / Chapter 5.2 --- Methods --- p.54 / Chapter 5.2.1 --- ABC method --- p.54 / Chapter 5.2.2 --- Morphometric analysis of tissue sections --- p.55 / Chapter 5.2.3 --- Statistical method --- p.56 / Chapter 5.3 --- Results / Chapter 5.3.1 --- Immunochemical results --- p.56 / Chapter 5.3.2 --- Morphometric results --- p.60 / Chapter 5.4 --- Discussions --- p.64 / Chapter VI.CHAPTER SIX --- Biochemical Assessments --- p.67 / Chapter 6.1 --- Water content / Chapter 6.1.1 --- Introduction --- p.67 / Chapter 6.1.2 --- Methods --- p.68 / Chapter 6.1.2.1 --- Water content measurement --- p.68 / Chapter 6.1.2.2 --- Statistical method --- p.69 / Chapter 6.1.3 --- Results --- p.72 / Chapter 6.1.4 --- Discussions --- p.77 / Chapter 6.2 --- Total collagen content / Chapter 6.2.1 --- Introduction --- p.81 / Chapter 6.2.1.1 --- Hydroxyproline as an indicator for collagen content assay --- p.81 / Chapter 6.2.2 --- Methods / Chapter 6.2.2.1 --- Hydrolysis method --- p.82 / Chapter 6.2.2.2 --- Standard-curve preparation --- p.83 / Chapter 6.2.2.3 --- Statstical method --- p.84 / Chapter 6.2.3 --- Results --- p.84 / Chapter 6.2.4 --- Discussions --- p.89 / Chapter VII.CHAPTER SEVEN --- Discussion --- p.92 / Chapter VIII.CHAPTER EIGHT --- Summary and Conclusions --- p.103 / Appendix A : Histological reagents preparations --- p.106 / Appendix B : Staining procedures for standard H & E --- p.107 / Appendix C : Immunochemical staining reagents preparations --- p.108 / Appendix D : Staining procedure for StreptABComplex / HRP --- p.110 / AppendixE : Biochemical reagents and preparations --- p.111 / Appendix F : Hydrolysis method for the tendon --- p.112 / Appendix G : Standard-curve of hydroxyproline --- p.113 / Appendix H : Determination of optimal hours for collagen hydrolysis --- p.114 / REFERENCES --- p.115

Achilles tendinopathy is a prevalent, highly debilitating condition. It is believed to result from repetitive overuse, which creates micro-damage tendon, and initiates a catabolic cell response. The aetiology of tendinopathy remains poorly understood, therefore appropriate treatment remains unclear. Current data support the use of shock wave therapy and eccentric exercise as some of the more effective treatment options for tendinopathy. Studies have shown that these treatments generate perturbations within tendon at a frequency of approximately 8-12Hz. Consequently, it is hypothesised that 10Hz loading initiates increased anabolic tenocyte behaviour promoting tendon repair. The primary aim of this thesis is to investigate the effects of 10Hz perturbations on tenocyte metabolism, comparing tenocyte gene expression in response to a 10Hz and 1Hz loading profile. A variety of in vitro models for mechanically stimulating cells were explored, comparing tissue explants with isolated cells on a 2D or within a 3D collagen gel. The mechanical environment of each model was investigated, in addition to cell viability and gene stabilisation following strain, as needed for future cell studies. 3D collagen gels arose as the most suitable model. Human tenocytes from healthy semitendinosus and tendinopathic Achilles tendons were seeded into 3D collagen gels and subjected to cyclic strain at 10Hz and 1Hz to establish cell response. Tenocyte gene expression was characterised using qRT-PCR. Healthy tenocytes showed increased expression of all analysed genes in response to loading. Furthermore, the increase was significantly larger in the 10Hz loading group. Tendinopathic tenocytes showed a more varied response, possibly indicative of an early healing response. Nevertheless, the response to 10Hz loading was consistently greater than seen with 1Hz loading. Analysis of the signalling pathways involved suggested that the IL1 signalling pathway may be involved in the strain response reported. This study has demonstrated for the first time that loading at a frequency of 10Hz may enhance metabolic response in healthy tenocytes.

Warm-up routines commonly include stretching to increase flexibility (joint range of motion - ROM), optimise performance, and reduce the risk of injury. Literature suggests that static stretching as part of the warm-up routines decreases force and power production compared to an active warm-up or a warm-up including dynamic stretching, and therefore could be detrimental to performance. This has led to an increased interest in the use of dynamic stretching by many athletes while the benefits of such interventions and their potential mechanisms of action are not well understood. Studies presented in this thesis were conducted to examine the effects of acute dynamic stretching on aspects of performance (e.g. torque production capacity of the plantarflexors and running economy) and to identify possible neuromechanical mechanisms underpinning any potential changes. Furthermore, we attempted to examine whether altered pain tolerance/perception to stretch may be a contributing factor to the increased ROM using adaptations in the neural substrates involved by using functional magnetic resonance imaging (fMRI) technique. In the first study, both slow dynamic stretching and fast dynamic stretching increased ROM, and this was due to an increased tendon elongation. Importantly, dynamic stretching was not detrimental to the torque producing capacity of the ankle plantarflexors. Effects of dynamic stretching on the sensorimotor performance remained mainly unclear. Employment of shear wave elastography technique in the second study suggested an increase in muscle stiffness, a decrease in fascicle strain, and showed an increase in muscle thickness after dynamic stretching, supporting an increase in tendon compliance as a contributing factor to increased flexibility after dynamic stretching. In the third study, the improved running economy by dynamic stretching may be attributable to the decreased dynamic joint ankle and vertical stiffness. The fMRI study was not conclusive due to methodological issues. Present findings have practical implications for the use of dynamic stretching in sporting contexts.