Subject-specific responses to an adaptive ankle prosthesis during incline walking

Lamers, Erik; Eveld, Maura E.; Zelik, Karl E.

doi:10.1016/j.jbiomech.2019.07.017

Cited by 26 publications

(35 citation statements)

References 33 publications

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“…The biggest confound to the group level analysis was likely participants who exhibited monotonically increasing or decreasing trends in oxygen consumption over the A-B-A trials. Our study supports the conclusions of Lamers et al 14 who recently discussed similar challenges in interpreting group level statistical comparisons for a population of transtibial prosthesis users. Taken together, these findings highlight the benefits of using single-subject designs (including A-B-A protocols and subject-specific analysis methods) to gain more reliable insight regarding the effects of prosthetic interventions.…”

Section: Discussionsupporting

confidence: 91%

Adding a toe joint to a prosthesis: walking biomechanics, energetics, and preference of individuals with unilateral below-knee limb loss

McDonald

Teater

Cruz

et al. 2021

Sci Rep

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Toe joints play an important functional role in able-bodied walking; however, for prosthesis users, the effect of adding a toe joint to a passive prosthetic foot remains largely unknown. The current study explores the kinematics, kinetics, rate of oxygen consumption and user preference of nine individuals with below-knee limb loss. Participants walked on a passive prosthetic foot in two configurations: with a Flexible, articulating toe joint and with a Locked-out toe joint. During level treadmill gait, participants exhibited a decrease in Push-Off work when using the Flexible toe joint prosthesis versus the Locked toe joint prosthesis: 16% less from the prosthesis (p = 0.004) and 10% less at the center of mass level (p = 0.039). However, between configurations, participants exhibited little change in other gait kinematics or kinetics, and no apparent or consistent difference in the rate of oxygen consumption (p = 0.097). None of the traditional biomechanical or metabolic outcomes seemed to explain user preference. However, an unexpected and intriguing observation was that all participants who wore the prosthesis on their dominant limb preferred the Flexible toe joint, and every other participant preferred the Locked configuration. Although perhaps coincidental, such findings may suggest a potential link between user preference and limb dominance, offering an interesting avenue for future research.

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Section: Discussionsupporting

confidence: 91%

Adding a toe joint to a prosthesis: walking biomechanics, energetics, and preference of individuals with unilateral below-knee limb loss

McDonald

Teater

Cruz

et al. 2021

Sci Rep

Self Cite

View full text Add to dashboard Cite

show abstract

“…These semi-active feet are particularly promising in adapting to tasks beyond level-ground walking. Specifically, aligning the foot to more closely match the ramp angle ( i.e ., dorsiflexing the foot during ramp ascent and plantarflexing during ramp descent) reduces socket pressures and compensatory mechanisms [ 11 ], [ 14 ], [ 15 ]. Similar results have been found during stair ascent and descent [ 11 ].…”

Section: Introductionmentioning

confidence: 99%

Patient-Preferred Prosthetic Ankle-Foot Alignment for Ramps and Level-Ground Walking

Shepherd

Simon

Zisk

et al. 2021

IEEE Trans. Neural Syst. Rehabil. Eng.

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Patient preference of lower limb prosthesis behavior informally guides clinical decision making, and may become increasingly important for tuning new robotic prostheses. However, the processes for quantifying preference are still being developed, and the strengths and weaknesses of preference are not adequately understood. The present study sought to characterize the reliability (consistency) of patient preference of alignment during level-ground walking, and determine the patient-preferred ankle angle for ascent and descent of a 10° ramp, with implications for the design and control of robotic prostheses. Seven subjects with transtibial amputation walked over level ground, and ascended and descended a 10° ramp on a semi-active prosthetic ankle capable of unweighted repositioning in dorsiflexion and plantarflexion. Preferred ankle angle was measured with an adaptive forced-choice psychophysics paradigm, in which subjects walked on a randomized static ankle angle and reported whether they would prefer the ankle to be dorsiflexed or plantarflexed. Subjects had reliable preferences for alignment during level-ground walking, with deviations of 1.5° from preference resulting in an 84% response rate preferring changes toward the preference. Relative to level walking, subjects preferred 7.8° (SD: 4.8°) of dorsiflexion during ramp ascent, and 5.3° (SD: 3.8°) plantarflexion during ramp descent. As the ankle angle better matched the ramp angle, socket pressures and tibial progression (shank pitch) both more closely mirrored those during level walking. These findings provide baseline behaviors for prosthetic ankles capable of adapting to slopes based on patient preference, and provide strong evidence that people with transtibial amputation can finely perceive ankle alignment.

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“…Following these two paths in future research, a more individualized prosthetic foot prescription depending on user gait could be developed. The high gait variability between users, as described by Zelik et al, during incline walking, may call for user-specific prosthetic foot adjustability [33]. Safaeepour et al described the change in ankle quasistiffness, depending on the gait phase and speed of healthy subjects [34].…”

Section: Discussionmentioning

confidence: 99%

Comparison Method of Biomechanical Analysis of Trans-Tibial Amputee Gait with a Mechanical Test Machine Simulation

et al. 2021

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Energy-storing-and-returning prosthetic feet are frequently recommended for lower limb amputees. Functional performance and stiffness characteristics are evaluated by state-of-the-art biomechanical testing, while it is common practice for design engineers and researchers to use test machines to measure stiffness. The correlation between user-specific biomechanical measures and machine evaluation has not been thoroughly investigated, and mechanical testing for ramps is limited. In this paper, we propose a novel test method to assess prosthetic foot stiffness properties in the sagittal plane. First, biomechanical data were collected on five trans-tibial users using a variable stiffness prosthetic foot on a split-belt treadmill. Gait trials were performed on level ground and on an incline and a decline of 7.5°. The same prosthetic foot was tested on a roll-over test machine for the three terrains. The sagittal ankle moment and angle were compared for the two test methods. The dorsiflexion moment and angle were similar, while more variability was observed in the plantarflexion results. A good correlation was found for level-ground walking, while decline walking showed the largest differences in the results of the maximum angles. The roll-over test machine is a useful tool to speed up design iterations with a set design goal prior to user testing.

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Subject-specific responses to an adaptive ankle prosthesis during incline walking

Cited by 26 publications

References 33 publications

Adding a toe joint to a prosthesis: walking biomechanics, energetics, and preference of individuals with unilateral below-knee limb loss

Adding a toe joint to a prosthesis: walking biomechanics, energetics, and preference of individuals with unilateral below-knee limb loss

Patient-Preferred Prosthetic Ankle-Foot Alignment for Ramps and Level-Ground Walking

Comparison Method of Biomechanical Analysis of Trans-Tibial Amputee Gait with a Mechanical Test Machine Simulation

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