Christian Silva

SOME PROJECTS

Modeling of human gait with lower limb prostheses by simulation tools (An OpenSim application).

Abstract

Unilateral, transfemoral and transtibial amputees have altered gait mechanics, which can significantly affect their mobility. They lose the functional use of the ankle and knee muscles, which are critical during walking to provide body support, forward propulsion, leg-swing initiation and mediolateral balance. Thus, either muscles must compensate or the prosthesis must provide the functional tasks normally provided by the ankle and knee muscles. A prosthetic leg with socket, knee and foot on a unilateral transfemoral and transtibial amputee walking were generated, and muscle and prosthetic leg contributions to body support and propulsion and residual leg swing were quantified. Three-dimensional (3D) Inverse Kinematics simulations of amputee and non-amputee walking were generated to identify muscle and prosthesis contributions to amputee walking mechanics, including the subtasks of body support, forward propulsion and leg-swing initiation and mediolateral balance. (Anne K. Silverman and Richard R Neptune 2012) Most transfemoral and transtibial prosthetic legs are designed to improve amputee gait. However, how prosthetic influences muscle and gait function is unclear. Identifying these relationships would provide quantitative rationale for prosthetic leg prescription that may lead to improved amputee gait. The purpose of this study was to identify the influence of prosthetic leg on muscle and gait function using inverse kinematics of amputee walking and compare it with the normal Human gait patterns. (Nicholas P. Fey et al., 2013)

Results showed that the prosthesis provided body support in the absence of the ankle and knee muscles. These results provide further insight into muscle and prosthesis function in transfemoral and transtibial amputee walking and can help guide rehabilitation methods and device designs to improve amputee mobility. Conclusions.  Thus, several muscle compensations were necessary. The prosthesis contributed to braking from early to mid-stance and propulsion in late stance (that depending on the kind of foot). The prosthesis also functioned like… ((Which muscles exactly??) (Anne K. Silverman and Richard R Neptune 2012)   ).. the uniarticular soleus muscle by transferring energy from the residual leg to the trunk to provide trunk propulsion. The residual-leg vasti and rectus femoris reduced their contributions to braking in early stance, which mitigated braking from the prosthesis during this period. The prosthesis did not replace the function of the gastrocnemius????, which normally generates energy to the leg to initiate swing. As a result, lower overall energy was delivered to the residual leg. The prosthesis also acted to accelerate the body laterally in the absence of the ankle and knee muscles. These results high light the influence of prosthetic leg has on muscle and gait function throughout the gait cycle and may aid in prescribing prosthetic legs for an appropriate walking behavior.

Keywords: Prosthetic, Gait Biomechanics, Inverse kinematics, Transtibial amputee, Transfemoral amputee.

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