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Clement J.,Ecole de Technologie Superieure of Montreal | Clement J.,Center Hospitalier Of Luniversite Of Montreal Crchum | Dumas R.,University of Lyon | Dumas R.,University Claude Bernard Lyon 1 | And 5 more authors.
Journal of Biomechanics | Year: 2015

Soft tissue artifact (STA) distort marker-based knee kinematics measures and make them difficult to use in clinical practice. None of the current methods designed to compensate for STA is suitable, but multi-body optimization (MBO) has demonstrated encouraging results and can be improved. The goal of this study was to develop and validate the performance of knee joint models, with anatomical and subject-specific kinematic constraints, used in MBO to reduce STA errors. Twenty subjects were recruited: 10 healthy and 10 osteoarthritis (OA) subjects. Subject-specific knee joint models were evaluated by comparing dynamic knee kinematics recorded by a motion capture system (KneeKG™) and optimized with MBO to quasi-static knee kinematics measured by a low-dose, upright, biplanar radiographic imaging system (EOS®). Errors due to STA ranged from 1.6° to 22.4° for knee rotations and from 0.8mm to 14.9mm for knee displacements in healthy and OA subjects. Subject-specific knee joint models were most effective in compensating for STA in terms of abduction-adduction, inter-external rotation and antero-posterior displacement. Root mean square errors with subject-specific knee joint models ranged from 2.2±1.2° to 6.0±3.9° for knee rotations and from 2.4±1.1mm to 4.3±2.4mm for knee displacements in healthy and OA subjects, respectively. Our study shows that MBO can be improved with subject-specific knee joint models, and that the quality of the motion capture calibration is critical. Future investigations should focus on more refined knee joint models to reproduce specific OA knee geometry and physiology. © 2015 Elsevier Ltd. Source


Forman J.L.,University of Virginia | Lopez-Valdes F.J.,University of Zaragoza | Duprey S.,Laboratoire Of Biomecanique Et Mecanique Des Chocs | Bose D.,The World Bank | And 5 more authors.
Accident Analysis and Prevention | Year: 2015

Road traffic injuries account for 1.3 million deaths per year world-wide. Mitigating both fatalities and injuries requires a detailed understanding of the tolerance of the human body to external load. To identify research priorities, it is necessary to periodically compare trends in injury tolerance research to the characteristics of injuries occurring in the field. This study sought to perform a systematic review on the last twenty years of experimental injury tolerance research, and to evaluate those results relative to available epidemiologic data. Four hundred and eight experimental injury tolerance studies from 1990-2009 were identified from a reference index of over 68,000 papers. Examined variables included the body regions, ages, and genders studied; and the experimental models used. Most (20%) of the publications studied injury to the spine. There has also been a substantial volume of biomechanical research focused on upper and lower extremity injury, thoracic injury, and injury to the elderly - although these injury types still occur with regularity in the field. In contrast, information on pediatric injury and physiological injury (especially in the central nervous system) remains lacking. Given their frequency of injury in the field, future efforts should also include improving our understanding of tolerances and protection of vulnerable road users (e.g., motorcyclists, pedestrians). © 2015 Elsevier Ltd. All rights reserved. Source


Patton D.A.,University of New South Wales | McIntosh A.S.,University of New South Wales | McIntosh A.S.,Monash University | Kleiven S.,KTH Royal Institute of Technology | Frechede B.,Laboratoire Of Biomecanique Et Mecanique Des Chocs
Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology | Year: 2012

Concussion is a prevalent injury in collision and contact sports, but the biomechanics of concussion has mainly been assessed for helmeted head impacts. Concussion and no-injury cases had previously been reconstructed using rigid body simulations from a larger video database of unhelmeted head impact cases from Australian rules football, rugby union and rugby league. The KTH finite element human head model was used to simulate the 27 concussion and 13 no-injury cases, and the maximum principle strain levels in the corpus callosum were evaluated. The rotational kinematics and strain levels were compared to critical strain tolerance curves and reconstructed pedestrian impacts from the literature. It was found that the 5% critical strain tolerance curve equated to a maximum principal strain level of approximately 0.20 and was associated with concussive impacts involving prolonged loss of consciousness. The results suggest rotational kinematics above 4500 rad/s2 and 33 rad/s for peak resultant angular acceleration and maximum change in resultant angular velocity, respectively, as tentative tolerance levels for concussion involving prolonged loss of consciousness. Cases involving short duration or no loss of consciousness had similar rotational kinematics and strain levels in the corpus callosum, suggesting that these injuries are of similar severity. The findings support the hypothesis that sports concussions share some biomechanical characteristics with diffuse axonal injury. © IMechE 2012. Source


Prat N.,French Armed Forces Institute of Biomedical Research IRBA | Rongieras F.,Desgenettes Military Academic Hospital | Rongieras F.,Laboratoire Of Biomecanique Et Mecanique Des Chocs | Sarron J.-C.,Directorate General of Armaments | And 2 more authors.
European Journal of Trauma and Emergency Surgery | Year: 2012

The introduction of firearms in the fifteenth century led to the continuous development of bulletproof personal protection. Due to recent industrial progress and the emergence of a new generation of ballistic fibers in the 1960s, the ability of individual ballistic protections to stop projectiles greatly increased. While protective equipment is able to stop increasingly powerful missiles, deformation during the impact can cause potentially lethal nonpenetrating injuries that are grouped under the generic term of behind armor blunt trauma, and the scope and consequences of these are still unclear. This review first summarizes current technical data for modern bulletproof vests, the materials used in them, and the stopping mechanisms they employ. Then it describes recent research into the specific ballistic injury patterns of soldiers wearing body armor, focusing on behind-armor blunt trauma. © 2012 Springer-Verlag. Source


De Seze M.,Bordeaux University Hospital Center | Randriaminahisoa T.,Laboratoire Of Biomecanique Et Mecanique Des Chocs | Gaunelle A.,Bordeaux University Hospital Center | de Korvin G.,Center Hospitalier Prive Saint Gregoire | Mazaux J.-M.,Bordeaux University Hospital Center
Annals of Physical and Rehabilitation Medicine | Year: 2013

The objective of this work was to analyze the inter-observer reproducibility of an upright posture designed to bring out the thoracic humps by folding the upper limbs. The effect of this posture on back surface parameters was also compared with two standard radiological postures. A back surface topography was performed on 46 patients (40 girls and 6 boys) with a minimum of 15° Cobb angle on coronal spinal radiographs. Inter-observer reliability was evaluated using the typical error measurement (TEM) and Intraclass Correlation Coefficient (ICC). Variations between postures were assessed using a Student's t test. The inter-observer reproducibility is good enough for the three postures. The proposed posture leads to significant changes in the sagittal plane as well as in the identification of thoracic humps. This study shows the reproducibility of the proposed posture in order to explore the thoracic humps and highlights its relevance to explore scoliosis with back surface topography systems. © 2013 Elsevier Masson SAS. Source

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