The Effect of Prosthetic Foot Component Stiffness on Gait Initiation and Termination of Transtibial Amputees

2012 ◽  
Author(s):  
Travis J. Peterson ◽  
Michelle Roland ◽  
Peter Adamczyk ◽  
Michael E. Hahn
Keyword(s):  
Lower Limb ◽  
Gait Initiation ◽  
Gait Stability ◽  
Functional Activities ◽  
Prosthetic Foot ◽  
Limb Stiffness ◽  
Stiffness Characteristics ◽  
And Performance ◽  
Transtibial Amputees ◽  
Lower Limb Amputees

Matching a prosthetic foot to meet the activity requirements of the user can be a difficult process. The ideal stiffness characteristics of different functional activities may vary. This variation dictates that the prescribed foot must be a compromise of multiple ideals due to functional necessity. The effects of lower limb stiffness have been studied in regards to their ability to reproduce “normal” lower limb mechanics [1,2]. Other studies have tracked gait stability and performance measures for lower limb amputees during gait initiation and termination [3–5]. However, it remains unknown what effects prosthetic stiffness may have on amputee function during gait initiation and termination. The objective of this study was to compare the effects of different component stiffness ranges on locomotion and stability measures during gait initiation and termination

Biomechanical Model Representing Energy Storing Prosthetic Feet

2010 ◽  
Author(s):  
Francy L. Sinatra ◽  
Stephanie L. Carey ◽  
Rajiv Dubey
Keyword(s):  
Motion Analysis ◽  
Lower Limb ◽  
Biomechanical Model ◽  
Body Segment ◽  
Prosthetic Foot ◽  
Biomechanical Models ◽  
Prosthetic Feet ◽  
Analysis System ◽  
Lower Limb Amputees ◽  
Metabolic Information

Previous studies have been conducted to develop a biomechanical model for a human’s lower limb. Amongst them, there have been several studies trying to quantify the kinetics and kinematics of lower-limb amputees through motion analysis [5, 10, 11]. Currently, there are various designs for lower-limb prosthetic feet such as the Solid Ankle Cushion Heel (SACH) from Otto Bock (Minneapolis) or the Flex Foot from Ossur (California). The latter is a prosthetic foot that allows for flexibility while walking and running. Special interest has been placed in recording the capabilities of these energy-storing prosthetic feet. This has been done through the creation of biomechanical models with motion analysis. In these previous studies the foot has been modeled as a single rigid-body segment, creating difficulties when trying to calculate the power dissipated by the foot [5, 20, 21]. This project studies prosthetic feet with energy-storing capabilities. The purpose is to develop an effective way of calculating power by using a biomechanical model. This was accomplished by collecting biomechanical data using an eight camera VICON (Colorado) motion analysis system including two AMTI (BP-400600, Massachusetts) force plates. The marker set that was used, models the foot using several segments, hence mimicking the motion the foot undergoes and potentially leading to greater accuracy. By developing this new marker set, it will be possible to combine the kinematic and kinetic profile gathered from it with previous studies that determined metabolic information. This information will allow for the better quantification and comparison of the energy storage and return (ES AR) feet and perhaps the development of new designs.

Effect of Walking Speed on Angular Stiffness and Roll-Over Shape of the Intact and Prosthetic Feet of Transtibial Amputees

2013 ◽  
Author(s):  
Michelle Roland ◽  
Peter G. Adamczyk ◽  
Michael E. Hahn
Keyword(s):  
Lower Limb ◽  
Stance Phase ◽  
Walking Speed ◽  
Plantar Flexor ◽  
Limb Function ◽  
Prosthetic Foot ◽  
Material Stiffness ◽  
Prosthetic Feet ◽  
Transtibial Amputees ◽  
Lower Limb Function

The calculated roll-over shape and respective radius of intact and prosthetic feet has been shown to be a useful measure of lower limb function during walking [1–2]. Hansen et al [3] reported that the roll-over radius, R, is constant over a range of speeds for the intact foot-ankle system. It may be assumed that the prosthetic foot R would also be constant with increased walking speed. Similarly, the angular stiffness of prosthetic feet is not likely to change with walking speed, as the material stiffness remains unchanged. However, the effective angular stiffness of the intact ankle may increase with the plantar flexor moment during the stance phase of gait, which typically increases in magnitude with walking speed.

scholarly journals Gait initiation in lower limb amputees

2008 ◽  
Vol 27 (3) ◽  
pp. 423-430 ◽  
Author(s):  
A.H. Vrieling ◽  
H.G. van Keeken ◽  
T. Schoppen ◽  
E. Otten ◽  
J.P.K. Halbertsma ◽  
...  
Keyword(s):  
Lower Limb ◽  
Gait Initiation ◽  
Lower Limb Amputees

scholarly journals An Interim Prosthesis Program for Lower Limb Amputees: Comparison of Public and Private Models of Service

2010 ◽  
Vol 34 (2) ◽  
pp. 175-183 ◽  
Author(s):  
Robert Gordon ◽  
Christopher Magee ◽  
Anna Frazer ◽  
Craig Evans ◽  
Kathryn McCosker
Keyword(s):  
Clinical Outcomes ◽  
Lower Limb ◽  
Labour Cost ◽  
Mechanical Prosthesis ◽  
Public And Private ◽  
The Public ◽  
Patient Groups ◽  
Transtibial Amputees ◽  
Lower Limb Amputees

This study compared the outcomes of an interim mechanical prosthesis program for lower limb amputees operated under a public and private model of service. Over a two-year period, 60 transtibial amputees were fitted with an interim prosthesis as part of their early amputee care. Thirty-four patients received early amputee care under a public model of service, whereby a prosthetist was employed to provide the interim mechanical prosthesis service. The remaining 26 patients received early amputee care under a private model of service, where an external company was contracted to provide the interim mechanical prosthesis service. The results suggested comparable clinical outcomes between the two patient groups. However, the public model appeared to be less expensive with the average labour cost per patient being 29.0% lower compared with the private model. The results suggest that a public model of service may provide a more comprehensive and less expensive interim prosthesis program for lower limb amputees.

Walking Mode Classification From Myoelectric and Inertial Fusion

2012 ◽  
Author(s):  
Jason D. Miller ◽  
Mahyo Seyedali ◽  
Michael E. Hahn
Keyword(s):  
Lower Limb ◽  
Metabolic Energy ◽  
Human Ankle ◽  
Different Types ◽  
Transfemoral Amputees ◽  
Mechanical Sensor ◽  
Inertial Measurements ◽  
Transtibial Amputees ◽  
Lower Limb Amputees ◽  
The Ideal

Transtibial amputees are generally restricted to the use of non responsive prosthetic systems which have been shown to require increased metabolic energy during normal gait [1] and can contribute to pain in the residual limb [2] among other unfavorable outcomes. Development of responsive lower limb prostheses is restricted due to the function of the human ankle which changes based on speed and type of locomotion. The ideal prosthetic would detect the patient’s motion intent to match both intensity and type of locomotion task. Implementation of motor intent detection should help restore normal limb function. Recent advances have shown the benefit of myoelectric and mechanical sensor fusion towards motion intent classifications. For upper limb amputees, a single accelerometer has shown benefit in classifying different types of hand grasps [3]. For transfemoral amputees a 6 axis pylon-implanted load cell has allowed increased walking mode classification accuracy [4]. It is believed that the continued exploration of EMG and mechanical fusion strategies will advance myoelectric control towards the development of commercially available systems for lower limb amputees. The purpose of the current study was to evaluate the potential for walking mode classification from both electromyography (EMG) signals and inertial measurements units (IMUs).

scholarly journals Leg stiffness of sprinters using running-specific prostheses

2012 ◽  
Vol 9 (73) ◽  
pp. 1975-1982 ◽  
Author(s):  
Craig P. McGowan ◽  
Alena M. Grabowski ◽  
William J. McDermott ◽  
Hugh M. Herr ◽  
Rodger Kram
Keyword(s):  
Ground Reaction Forces ◽  
Mass Model ◽  
Leg Stiffness ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Stiffness Characteristics ◽  
And Performance ◽  
Vertical Ground Reaction Forces ◽  
Transtibial Amputees ◽  
Running Mechanics

Running-specific prostheses (RSF) are designed to replicate the spring-like nature of biological legs (bioL) during running. However, it is not clear how these devices affect whole leg stiffness characteristics or running dynamics over a range of speeds. We used a simple spring–mass model to examine running mechanics across a range of speeds, in unilateral and bilateral transtibial amputees and performance-matched controls. We found significant differences between the affected leg (AL) of unilateral amputees and both ALs of bilateral amputees compared with the bioL of non-amputees for nearly every variable measured. Leg stiffness remained constant or increased with speed in bioL, but decreased with speed in legs with RSPs. The decrease in leg stiffness in legs with RSPs was mainly owing to a combination of lower peak ground reaction forces and increased leg compression with increasing speeds. Leg stiffness is an important parameter affecting contact time and the force exerted on the ground. It is likely that the fixed stiffness of the prosthesis coupled with differences in the limb posture required to run with the prosthesis limits the ability to modulate whole leg stiffness and the ability to apply high vertical ground reaction forces during sprinting.

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