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Effect of alteration in hip joint alignment following total hip arthroplasty on hip joint contact force during gait

Hata Kazutaka, Ishido Yasuhiro, Fukudome Kiyohiro, Kiyama Ryoji, Kawada Masayuki, Nishi Tomohiro, Nakatsuji Shintaro, Yone Kazunori

Acta of Bioengineering and Biomechanics

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2023

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Vol. 25, no. 3

EN

Investigation of the relationship between changes in hip-joint center and hip loading pre- and post- total hip arthroplasty (THA) is important in evaluating the effect of surgery on motor function. However, few longitudinal studies comparing pre- and post-THA have been reported. The purpose of this study was to determine the effect of changes in hip-joint center pre- and post-THA on the magnitude and direction of hip-joint contact force during the gait cycle, using a patient-specific musculoskeletal model.

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Influence of modified muscle morphology and activity pattern on the results of musculoskeletal system modelling in cerebral palsy patient

Ogrodnik J., Piszczatowski Sz.

Acta of Bioengineering and Biomechanics

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2017

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Vol. 19, no. 3

63--75

EN

Purpose: The aim of the present study was to evaluate the influence of modified morphological parameters of the muscle model and excitation pattern on the results of musculoskeletal system numerical simulation in a cerebral palsy patient. Methods: The modelling of the musculoskeletal system was performed in the AnyBody Modelling System. The standard model (MoCap) was subjected to modifications consisting of changes in morphological parameters and excitation patterns of selected muscles. The research was conducted with the use of data of a 14-year-old cerebral palsy patient. Results: A reduction of morphological parameters (variant MI) caused a decrease in the value of active force generated by the muscle with changed geometry, and as a consequence the changes in active force generated by other muscles. A simulation of the abnormal excitation pattern (MII variant) resulted in the muscle’s additional activity during its lengthening. The simultaneous modification of the muscle morphology and excitation pattern (MIII variant) points to the interdependence of both types of muscle model changes. A significant increase in the value of the reaction force in the hip joint was observed as a consequence of modification of the hip abductor activity. Conclusions: The morphological parameters and the excitation pattern of modelled muscles have a significant influence on the results of numerical simulation of the musculoskeletal system functioning.

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Dissipation of disturbances seen in the knee joint kinematics of children with cerebral palsy

Kurz M. J., Arpin D. J., Davies D. L., Gehringer J. E.

Acta of Bioengineering and Biomechanics

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2015

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Vol. 17, no. 4

67--72

EN

Purpose: Children with cerebral palsy (CP) often use a crouch gait pattern that has disturbances in the knee joint kinematics. Although the length and rate of lengthening of the hamstring musculature have been speculated to be the reason that these disturbances are not adequately dissipated, this relationship has not been adequately explored. The purpose of this exploratory investigation was to use simulations of a musculoskeletal model and Floquet analysis to evaluate how the performance of hamstrings musculature during gait may be related to the knee joint instabilities seen in children with CP. Methods: Children with CP and typically developing (TD) children walked on a treadmill as a motion capture system assessed the knee joint kinematics. Floquet analysis was used to quantify the rate that disturbances present at the knee joint were dissipated, and simulations of a musculoskeletal model were used to estimate the in vivo length and velocity of the hamstrings. Pearson correlation coefficients were calculated to determine if there was a relationship between the rate that the disturbances were dissipated and the performance of the hamstring musculature. Results: The children with CP had hamstrings that lengthened more slowly than TD children, and required more strides to dissipate disturbances in the knee joint kinematics. There was negative correlation between the rate that the hamstrings lengthened and the rate that the knee joint disturbances were dissipated. Conclusions: Our results suggest that the ability of children with CP to dissipate the knee joint disturbances may be related to the inability to properly control the hamstring musculature.

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Dynamic simulation of tibialis posterior tendon transfer in the treatment of drop-foot

Kapti A. O.

Biocybernetics and Biomedical Engineering

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2014

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Vol. 34, no. 2

132--138

EN

An extensive range of studies have been performed to describe kinematics and dynamics of human movements. However, the forces and moments generated by muscles are not measurable. Dynamic simulations are needed to estimate internal loading of the musculo-skeletal system, to establish scientific basis of treatment planning before performing the surgery, and to predict the functional consequences of treatments. In this study, an ankle joint model consisting of 30 bones and 12 muscles was generated by using lower extremity model of OpenSim software. Muscle insertion points were virtually re-defined for simulation of tendon transfer operation of tibialis posterior in treatment of drop foot deformity. Flexion and inversion moments of ankle, and moment arm distances of tibialis posterior before and after operation were investigated comparatively. Tibialis posterior provided the dorsal flexion moment up to 28 N m after transfer, while providing the plantar flexion moment of -14.5 N m before transfer. Moment arm distance became average 33 mm after transfer, while it is average -11 mm before transfer. These increases provided the active dorsal flexion as the treatment of drop foot.