Design and Testing of a Prosthetic Foot With Interchangeable Custom Springs for Evaluating Lower Leg Trajectory Error, an Optimization Metric for Prosthetic Feet

Prost, Victor; Olesnavage, Kathryn M.; Johnson, W. Brett; Major, Matthew J.; Winter, V Amos G.

doi:10.1115/1.4039342

Cited by 10 publications

(8 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The experimental foot was tested on an Instron material testing machine (Instron, Norwood, MA) with each set of ankle flexures. Every ankle stiffness matched the specified value to within R 2 ¼ 0:98, and each demonstrated elastic behavior with minimal hysteresis and viscoelastic behavior [40]. Conditions A-C could safely reach a dorsiflexion angle of 26 deg without the material yielding and before hitting a hard stop.…”

Section: Methodsmentioning

confidence: 78%

“…The geometry of the foot was selected to replicate the articulation of the biological foot/ankle complex and was not included as a design variable to be optimized. (b) Solid model of the experimental foot built to function like the simple foot model in (a) [40]. The geometry of the U-shaped flexures dictates the stiffness of the ankle and can be substituted with other flexures to vary the ankle stiffness.…”

Section: Datamentioning

confidence: 99%

See 1 more Smart Citation

Experimental Demonstration of the Lower Leg Trajectory Error Framework Using Physiological Data as Inputs

Olesnavage

Prost

Johnson

et al. 2020

Journal of Biomechanical Engineering

Self Cite

View full text Add to dashboard Cite

While many studies have attempted to characterize the mechanical behavior of passive prosthetic feet to understand their influence on amputee gait, the relationship between mechanical design and biomechanical performance has not yet been fully articulated from a fundamental physics perspective. A novel framework, called Lower Leg Trajectory Error (LLTE) framework, presents a means of quantitatively optimizing the constitutive model of prosthetic feet to match a reference kinematic and kinetic dataset. This framework can be used to predict the required stiffness and geometry of a prosthesis to yield a desired biomechanical response. A passive prototype foot with adjustable ankle stiffness was tested by a unilateral transtibial amputee to evaluate this framework. The foot condition with LLTE-optimal ankle stiffness enabled the user to replicate the physiological target dataset within 16% RMS error. Specifically, the measured kinematic variables matched the target kinematics within 4% RMS error. Testing a range of ankle stiffness conditions from 1.5 to 24.4 Nm/deg with the same user indicated that conditions with lower LLTE values deviated the least from the target kinematic data. Across all conditions, the framework predicted the horizontal/vertical position, and angular orientation of the lower leg during mid-stance within 1.0 cm, 0.3 cm, and 1.5 degrees, respectively. This initial testing suggests that prosthetic feet designed with low LLTE values could benefit users. The LLTE framework is agnostic to specific foot designs and kinematic/kinetic user targets, and could be used to design and customize prosthetic feet.

show abstract

Section: Methodsmentioning

confidence: 78%

Section: Datamentioning

confidence: 99%

Experimental Demonstration of the Lower Leg Trajectory Error Framework Using Physiological Data as Inputs

Olesnavage

Prost

Johnson

et al. 2020

Journal of Biomechanical Engineering

Self Cite

View full text Add to dashboard Cite

show abstract

“…The foot was an energy storage and return design with a flexible cantilever beam forefoot and ankle joint with torsional stiffness provided by interchangeable springs. Ankle stiffness and forefoot length were customized for each participant based on height, body mass and intact foot length (refer to [ 12 ] for description and validation).…”

Section: Methodsmentioning

confidence: 99%

“…Participants wore their own footwear on their unimpaired side and comfortable clothing. The prototype foot [ 12 ] was designed to be used without a shoe, and the prosthetic limb was configured to account for this. Reflective markers were placed on the pelvis and bilaterally on the feet, lower legs and thighs (see Supplementary Information file S1 ).…”

Section: Methodsmentioning

confidence: 99%

“…All fitting and clinical alignment was performed by the same experienced prosthetist. Participants were fitted with a passive, single-axis prototype knee with a prototype foot [12], maintaining their existing socket and suspension. The knee unit, described in more detail in [13][14][15], permits adjustment of KFDSW via rotary hydraulic dampers attached to the medial or lateral aspect of the device.…”

Section: A Device and Device Configurationmentioning

confidence: 99%

See 1 more Smart Citation

Knee Swing Phase Flexion Resistance Affects Several Key Features of Leg Swing Important to Safe Transfemoral Prosthetic Gait

Kent

Arelekatti

Petelina

et al. 2021

IEEE Trans. Neural Syst. Rehabil. Eng.

Self Cite

View full text Add to dashboard Cite

We systematically investigate in-vivo the effect of increasing prosthetic knee flexion damping on key features of the swing phase of individuals with transfemoral amputation during walking. Five experienced prosthesis users walked using a prototype device in a motion capture laboratory. A range of interchangeable hydraulic rotary dampers was used to progressively modify swing phase flexion resistance in isolation. Toe clearance (TC; vertical distance toe to floor), effective leg length (ELL; distance hip to toe), and knee flexion angle during swing phase were computed, alongside the sensitivities of vertical toe position to angular displacements at the hip, knee and ankle. Key features of these profiles were compared across 5 damping conditions. With higher damping, knee extension occurred earlier in swing phase, promoting greater symmetry. However, with implications for toe catch, minimum TC reduced, and minimum TC and maximum ELL occurred earlier; temporally closer to mid-swing, when the limb must pass the stance limb. Further, TC became less sensitive to changes in hip flexion, suggesting a lesser ability to control toe clearance without employing proximal or contralateral compensations. There is a trade-off between key features related to gait safety when selecting an appropriate resistance for a mechanical prosthetic knee. In addition to highlighting broader implications surrounding swing phase damping selection for the optimization of mechanical knees, this work reveals design considerations that may be of utility in the formulation of control strategies for computerized devices.

show abstract

Design of Asymmetric Parallel Manipulator for Axial-Bending Dynamic Stiffness Analysis

Torres¹,

Soliman²,

Ribeiro³

et al. 2022

IFAC-PapersOnLine

View full text Add to dashboard Cite

Design and Testing of a Prosthetic Foot With Interchangeable Custom Springs for Evaluating Lower Leg Trajectory Error, an Optimization Metric for Prosthetic Feet

Cited by 10 publications

References 10 publications

Experimental Demonstration of the Lower Leg Trajectory Error Framework Using Physiological Data as Inputs

Experimental Demonstration of the Lower Leg Trajectory Error Framework Using Physiological Data as Inputs

Knee Swing Phase Flexion Resistance Affects Several Key Features of Leg Swing Important to Safe Transfemoral Prosthetic Gait

Design of Asymmetric Parallel Manipulator for Axial-Bending Dynamic Stiffness Analysis

Contact Info

Product

Resources

About