2,438 research outputs found
RECONSTRUCTION OF PATIENT-SPECIFIC TIBIOFEMORAL JOINT ARTICULATIONS FROM MARKER TRAJECTORIES AND ANTHROPOMETRICS
No full textPatient-specific modelling through incorporating magnetic resonance imaging (MRI) improves biofidelity with respect to articulations, particularly at the knee [1]. However, these models can be both labour and time intensive, and access to MRI is not possible for all researchers. Principal component analysis (PCA) has been used to facilitate the reconstruction of articular surface features from existing morphology in adults [2]. The purpose of this research was to determine if patient-specific articulations of the tibiofemoral joint (TFJ) could be reconstructed from marker positions and anthropometrics in paediatric knees
DEVELOPMENT OF A CONGRUENCE-BASED MUSCULOSKELETAL MODEL OF THE KNEE IN ANTERIOR CRUCIATE LIGAMENT INJURED ADOLESCENTS
No full textAnterior cruciate ligament (ACL) injury rates are rising in adolescent populations [1]. To understand how an individual’s joint morphology dictates their motion patterns, researchers have developed patient-specific musculoskeletal models using medical images of the tibiofemoral joint (TFJ) to study ACL injuries [2]. In particular, congruence-based modelling optimizes the configuration of the tibiofemoral joint to reduce pressure during movement [3], mimicking the mechanotransduction properties of articular cartilage [4]. However, these models have predominantly been constructed using adult knees, and it is unclear if patient-specific models can be built for populations undergoing pubertal development. Therefore, the purpose of this research is to build a patient-specific knee model for modelling passive knee joint motion during adolescence
DEVELOPMENT OF A CONGRUENCE-BASED MUSCULOSKELETAL MODEL OF THE KNEE IN ANTERIOR CRUCIATE LIGAMENT INJURED ADOLESCENTS
No full textAnterior cruciate ligament (ACL) injury rates are rising in adolescent populations [1]. In order to better understand how an individual’s joint morphology dictates their motion patterns, researchers have developed patient-specific musculoskeletal models using medical images of the tibiofemoral joint (TFJ) to study ACL injuries [2]. In particular, congruence-based modelling optimizes the configuration of the tibiofemoral joint to reduce pressure during movement [3], mimicking the mechanotransduction properties of articular cartilage [4]. However, these models have predominantly been constructed using adult knees, and it is unclear if patient-specific models can be developed for a growing population. Therefore, the purpose of this research is to build a patient-specific knee model for modelling passive knee joint motion during adolescence
La Figure de la maison dans trois romans franco-canadiens contemporains
No full text"Ce mémoire étudie la figure de la maison dans trois romans franco-canadiens contemporains : La maison habitée (2014) de Geneviève Lévesque, La maison. Une parabole (2009) de Daniel Soha et La maison-mémoire (2007) de Sandra Rompré-Deschênes. Dans ces trois romans, un personnage souvent seul se retrouve dans une maison qui devient pour lui une prison, un bateau ou encore un labyrinthe. Le préconstrit de l'espace devient plus signifiant que le temps, les personnages ou les actions. Sur le plan théorique, nous avons appliqué l'herméneutique des espaces fictionnels de Benoit Doyon-Gosselin. Cette approche lie les trois concepts centraux de l'herméneutique (compréhension, explication et interprétation) à trois concepts spatiaux (les figures spatiales, la configuration et la refiguration spatiale). L'analyse des espaces fictionnels de Benoit Doyon-Gosselin nous oriente à mieux comprendre et interpréter les particularités des maisons mises en scène. L'analyse de la maison dans les trois romans retenus montre que le préconstruit de l'espace peut jouer un rôle signifiant dans la fiction."--Résumé.statement of responsibility: Hamed Mahaman Arouna."Thèse présentée pour satisfaire aux exigences de la maîtrise ès arts (études littéraires)".thesis: M. A. (études littéraires) Université de Moncton 2017bibliography: Comprend des références bibliographiques : feuilles 73-74.additional physical form: Également disponible en version électronique. Les pages contenant des informations personnelles ne sont pas reproduites
Supplemental Material, sj-pdf-1-ojs-10.1177_23259671231154540 - Criteria Used to Determine Unrestricted Return to Activity After ACL Reconstruction in Pediatric and Adolescent Patients: A Systematic Review
No full textSupplemental Material, sj-pdf-1-ojs-10.1177_23259671231154540 for Criteria Used to Determine Unrestricted Return to Activity After ACL Reconstruction in Pediatric and Adolescent Patients: A Systematic Review by Nicholas J. Romanchuk, Holly Livock, Kenneth J. Lukas, Michael J. Del Bel, Daniel L. Benoit and Sasha Carsen in Orthopaedic Journal of Sports Medicine</p
Motion analysis of the knee : kinematic artifacts, EMG normalisation and joint forces
No full textThe non-contact anterior cruciate ligament (ACL) injury is the most common and serious debilitating knee joint injury in male and female athletes. To create an ACL injury paradigm that will lead to improved treatment and prevention it is necessary to understand how ACL injuries occur. Currently this information is lacking for reasons such as differing methodologies used in studies of neuromuscular control of the leg muscles, lack of information related to the role of sports equipment in affecting knee joint forces, and insufficient measurement accuracy of 3D knee joint kinematics.The aim of this thesis is to address some of these issues by: (1) evaluating techniques of electromyography (EMG) analysis with ACL patients; (2) investigating the contribution of sports equipment to reducing knee joint forces in skiing; (3) assessing the accuracy of non-invasive motion analysis techniques in measuring true bone motion and verifying techniques to improve the accuracy.We identified that EMG normalisation methods would significantly affect the ability to detect neuromuscular alterations between injured and non-injured leg muscles in ACL injured subjects. We found that clinical outcome measures of neuromuscular control were dependant on normalisation and that the MVC method was most sensitive at detecting injured to non-injured limb neuromuscular alterations. We also provided evidence of reduced gastrocnemius muscle activity in ACL injured patients. We found that the release and rotation of the ski boot cuff both increased knee joint compressive force and reduced anterior shear force. The important role of sports equipment in contributing to injury prevention was established.Finally, by measuring in-vivo tibio-femoral motion and comparing it with noninvasive skin marker techniques we found average rotation errors of 4.4 degrees and 13.1 degrees and translation errors of 13.0 and 16.1 mm for rotations during walking and cutting respectively. Skin markers did not accurately reflect tibio-femoral joint motion. The error introduced due to skin movement artifact affected both the magnitude and direction of reported tibio-femoral motions during the walk and cut. Although we were not able to improve the measured kinematics by reducing intermarker movements, we have proposed a standard error of measurement to be used when reporting knee joint motion data in the future. We believe that the content of this thesis provides a solid foundation from which to build an ACL injury paradigm and provides insight into factors associated with performing motion analysis of the knee.List of scientific papersI. Benoit DL, Lamontagne M, Cerulli G, Liti A (2003). The clinical significance of electromyography normalisation techniques in subjects with anterior cruciate ligament injury during treadmill walking. Gait Posture. 18(2): 56-63. https://doi.org/10.1016/S0966-6362(02)00194-7 II. Benoit DL, Lamontagne M, Greaves C, Liti A, Cerulli G (2005). Effect of alpine ski boot cuff release on knee joint force during the backward fall. [Submitted]III. Ramsey DK, Wretenberg PF, Benoit DL, Lamontagne M, Nemeth G (2003). Methodological concerns using intra-cortical pins to measure tibiofemoral kinematics. Knee Surg Sports Traumatol Arthrosc. 11(5): 344-9. https://doi.org/10.1007/s00167-003-0388-1 IV. Benoit DL, Ramsey D, Lamontagne M, Xu L, Wretenberg P, Renstrom P (2005). Effect of skin movement artefact on knee kinematics during gait and cutting motions measured in-vivo. [Accepted] https://doi.org/10.1016/j.gaitpost.2005.04.012 V. Benoit DL, Ramsey D, Lamontagne M, Xu L, Renstrom P (2005). Can surface markers optimisation reduce skin movement during gait and cutting motions. [Manuscript]</p
Inclusion of MRI for patient-specific modelling in Opensim
No full textGeneric OpenSim models such as the Rajagopal model [1] have questionable biofidelity as they are comprised of a single degree of freedom (dof) knee joint while the remaining five degrees are prescribed based on in vitro cadaver work. To enhance the validity of these models, magnetic resonance imaging (MRI) can be incorporated to satisfy appropriate patient-specific bone geometry, muscle wrapping, and ligament lengths. The purpose of this study was to evaluate kinematics and ligament lengths when adapting the Rajagopal model to include an MRI-based knee contact model
Effect of implementing magnetic resonance imaging for patient-specific OpenSim models on lower-body kinematics and knee ligament lengths
No full textBackground: OpenSim models are typically based on cadaver findings that are generalized to represent a wide range of populations, which curbs their validity. Patient-specific modelling through incorporating magnetic resonance imaging (MRI) improves the model's biofidelity with respect to joint alignment and articulations, muscle wrapping, and ligament insertions. The purpose of this study was to determine if the inclusion of an MRI-based knee model would elicit differences in lower limb kinematics and resulting knee ligament lengths during a side cut task. Methods: Eleven participants were analyzed with the popular Rajagopal OpenSim model, two variations of the same model to include three and six degrees of freedom knee (DOF), and a fourth version featuring a four DOF MRI-based knee model. These four models were used in an inverse kinematics analysis of a side cut task and the resulting lower limb kinematics and knee ligament lengths were analyzed. Results: The MRI-based model was more responsive to the movement task than the original Rajagopal model while less susceptible to soft tissue artifact than the unconstrained six DOF model. Ligament isometry was greatest in the original Rajagopal model and smallest in the six DOF model. Conclusions: When using musculoskeletal modelling software, one must acutely consider the model choice as the resulting kinematics and ligament lengths are dependent on this decision. The MRI-based knee model is responsive to the kinematics and ligament lengths of highly dynamic tasks and may prove to be the most valid option for continuing with late-stage modelling operations such as static optimization
Benoit B. Mandelbrot (1924-2010)
No full textBenoit B. Mandelbrot, who advanced the concept of power law scaling as a fundamental property of a broad range of natural processes and patterns in geophysics, economics, mathematics, and virtually all of science, died on 14 October 2010 in Cambridge, Mass., at the age of 85. Mandelbrot, known as the “father of fractal geometry,” was a mathematician who developed the scaling concepts of self-similarity and self-affinity and found examples in spatial, temporal, and size patterns across a broad spectrum of disciplines. He coined the term “fractal” (from the Latin noun “fractus,” meaning fragmented) for shapes and patterns that exhibit self-similarity, meaning that they are statistically scale independent. Such shapes are characterized by fractional power law exponents, between the integer (Euclidean) dimensions. He is best known through his books, including Les Objets Fractals: Forme, Hasard et Dimension; Fractals: Form, Chance and Dimension; The Fractal Geometry of Nature; andMultifractals and 1/f Noise: Wild Self-Affinity in Physics [Mandelbrot, 1975, Mandelbrot1977, Mandelbrot 1982, Mandelbrot 1999]
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