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Is the human acetabulofemoral joint spherical?

Authors:
  • University of Rome Foro Italico

Abstract

The human acetabulofemoral joint is commonly modelled as a pure ball-and-socket joint, but there has been no quantitative assessment of this assumption in the literature. Our aim was to test the limits and validity of this hypothesis. We performed experiments on four adult cadavers. Cortical pins, each equipped with a marker cluster, were implanted in the pelvis and the femur. Movements were recorded using stereophotogrammetry while an operator rotated the cadaver’s acetabulofemoral joint, exploiting the widest possible range of movement. The functional consistency of the acetabulofemoral joint as a pure spherical joint was assessed by comparing the magnitude of the translations of the hip joint centre as obtained on cadavers, with the centre of rotation of two metal segments linked through a perfectly spherical hinge. The results showed that the radii of the spheres containing 95% of the positions of the estimated centres of rotation were separated by less than 1 mm for both the acetabulofemoral joint and the mechanical spherical hinge. Therefore, the acetabulofemoral joint can be modelled as a spherical joint within the considered range of movement (flexion/extension 20° to 70°; abduction/adduction 0° to 45°; internal/external rotation 0° to 30°).
... According to research conducted in the field of rehabilitation medicine [29][30], this section proposes the notion that movements occurring in the sagittal plane exert a more profound influence compared to those in the coronal and horizontal planes during regular walking. As a result, the analysis of the dynamics of the lowerlimb exoskeleton rehabilitation robot solely considers alterations in the sagittal plane. ...
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The utilization of the LLE offers a highly effective means of enhancing walking ability for individuals with permanent leg weakness, surpassing that of a wheelchair. For individuals experiencing permanent leg weakness, the utilization of the LLE represents a highly effective means to enhance their walking ability, The joint's actuator model is developed using the Matlab system identification technique. The actuators are interconnected with the LLE and payload, enabling an examination of the LLE's dynamics. A three-dimensional model of the LLE is fabricated using Solidworks software, and a simulation approach is implemented using SimMechanics.. Afterwards, the model is verified through simulation, incorporated with a Matlab-Simulink control model, and subjected to testing in both payload and non-payload conditions.The results demonstrate that the model can be effectively employed in simulation to verify the controller performance for tracking the trajectory of LLE walking. The RMS error of the joint angle is minimal and closely approximates the desired input of the joint with high velocity in the absence of payload, while in the presence of payload, the torque of the joint adapts well under high load. This behavior is highly logical during walking. The implementation of the PID controller enhances system stability by reducing the step response of the joint position, thereby providing accurate angles in less time and with reduced vibration.
... AlphaPose, OpenPose) ( [5], [16]- [18]), not necessarily gait, and training relies on reference data not based on clinical gait analysis standards [29] (e.g. clear and anatomical/functional rules for joint centers definition [30]). Furthermore, original training data sets do not include people with impaired gait and, therefore, methods performance is not optimized and clinical validity is not established. ...
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... According to research conducted in the field of rehabilitation medicine [29][30], this section proposes the notion that movements occurring in the sagittal plane exert a more profound influence compared to those in the coronal and horizontal planes during regular walking. As a result, the analysis of the dynamics of the lowerlimb exoskeleton rehabilitation robot solely considers alterations in the sagittal plane. ...
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The utilization of the LLE offers a highly effective means of enhancing walking ability for individuals with permanent leg weakness, surpassing that of a wheelchair. For individuals experiencing permanent leg weakness, the utilization of the LLE represents a highly effective means to enhance their walking ability, The joint's actuator model is developed using the Matlab system identification technique. The actuators are interconnected with the LLE and payload, enabling an examination of the LLE's dynamics. A three-dimensional model of the LLE is fabricated using Solidworks software, and a simulation approach is implemented using SimMechanics.. Afterwards, the model is verified through simulation, incorporated with a Matlab-Simulink control model, and subjected to testing in both payload and non-payload conditions.The results demonstrate that the model can be effectively employed in simulation to verify the controller performance for tracking the trajectory of LLE walking. The RMS error of the joint angle is minimal and closely approximates the desired input of the joint with high velocity in the absence of payload, while in the presence of payload, the torque of the joint adapts well under high load. This behavior is highly logical during walking. The implementation of the PID controller enhances system stability by reducing the step response of the joint position, thereby providing accurate angles in less time and with reduced vibration.
... Andersen et al., 2009;Duprey et al., 2010;Reinbolt et al., 2005) : n'autorise qu'une rotation autour d'un seul axe prédéfini (un degré de liberté) et aucune translation • Rotule à doigt, ellipsoïde et joint de cardan(Andersen et al., 2009;Duprey et al., 2010;Reinbolt et al., 2005) : autorise la rotation autour de deux axes (deux degrés de liberté) et aucune translation.• Rotule ou sphéroïde(Cereatti et al., 2010) : autorise les trois rotations dans l'espace (3 degrés de liberté), mais aucune translation.• Sphère sur plan ou ponctuelle (Parenti-Castelli et al., 2004) : autorise les trois rotations et deux translations sur le plan (cinq degrés de liberté). ...
Thesis
L’analyse du mouvement humain est un paramètre clé pour comprendre les différentes problématiques de la locomotion humaine. Qui plus est, il est nécessaire que ces analyses soient effectuées au plus proche de la locomotion réelle. L’essor de la miniaturisation des capteurs et des technologies sans fil a permis d’offrir la possibilité d’utiliser les centrales inertielles sur le terrain. Mais différentes problématiques existent encore pour obtenir la cinématique des membres inférieurs avec les centrales inertielles.La première étude de ce manuscrit aborde une comparaison des différents calibrages centrale-à-segment pour définir le passage entre l’orientation de la centrale inertielle et le segment sous-jacent. Nous avons mis en avant une méthode qui valide ces critères au mieux et ne demande que deux postures et un dispositif simple. Mais la cinématique obtenue reste entachée d’erreurs qui pourraient être dues à la présence d’artefacts de tissu mou.C’est pourquoi dans une seconde partie nous étudions la possibilité de diminuer ces effets par l’intermédiaire de l’optimisation multisegmentaire. Ainsi nous avons pu mettre en avant la nécessité de bien paramétrer le modèle derrière l’optimisation sans pour autant présenter un apport significatif. Enfin, en dernière partie, nous proposons d’appliquer la méthodologie de traitement de la cinématique articulaire sur une population pathologique, en collaboration avec le laboratoire de cinésiologie Willy Taillard des HUG et de l’Université de Genève. En conclusion cette thèse propose un processus méthodologique et des recommandations pour développer des analyses de la cinématique en milieu écologique avec des centrales inertielles.
... The joints of a lower limb can be modeled as a spherical joint within the considered range of movement. 36 Referring to the fundamental and basic axes defined in the anatomy, the basic forms of joint motion can be classified into three categories: flexion/extension (FE) around the frontal axis, abduction/adduction (AA) around the sagittal axis, and internal/external (IE) around the vertical axis. Degrees of freedom (DOF) is used as a term to describe the freedom of motion. ...
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