scholarly journals Stance Phase Kinematics in Ankle Joint during Ambulation on Uneven Surface: A Comparison between Stroke Survivors and Typical Adults

2020 ◽  
Vol 31 (3) ◽  
pp. 164
Author(s):  
Muhammed Rashid ◽  
Jerin Mathew ◽  
Kavitha Raja
Keyword(s):  
Ankle Joint ◽  
Stance Phase ◽  
Stroke Survivors ◽  
Uneven Surface

scholarly journals Measurement of passive ankle stiffness in subjects with chronic hemiparesis using a novel ankle robot

2011 ◽  
Vol 105 (5) ◽  
pp. 2132-2149 ◽  
Author(s):  
Anindo Roy ◽  
Hermano I. Krebs ◽  
Christopher T. Bever ◽  
Larry W. Forrester ◽  
Richard F. Macko ◽  
...  
Keyword(s):  
Ankle Joint ◽  
Frontal Plane ◽  
Chronic Stroke ◽  
Healthy Adults ◽  
Stroke Survivors ◽  
Passive Stiffness ◽  
Mechanical Stiffness ◽  
Treatment Protocols ◽  
Ankle Stiffness ◽  
Hemiparetic Stroke

Our objective in this study was to assess passive mechanical stiffness in the ankle of chronic hemiparetic stroke survivors and to compare it with those of healthy young and older (age-matched) individuals. Given the importance of the ankle during locomotion, an accurate estimate of passive ankle stiffness would be valuable for locomotor rehabilitation, potentially providing a measure of recovery and a quantitative basis to design treatment protocols. Using a novel ankle robot, we characterized passive ankle stiffness both in sagittal and in frontal planes by applying perturbations to the ankle joint over the entire range of motion with subjects in a relaxed state. We found that passive stiffness of the affected ankle joint was significantly higher in chronic stroke survivors than in healthy adults of a similar cohort, both in the sagittal as well as frontal plane of movement, in three out of four directions tested with indistinguishable stiffness values in plantarflexion direction. Our findings are comparable to the literature, thus indicating its plausibility, and, to our knowledge, report for the first time passive stiffness in the frontal plane for persons with chronic stroke and older healthy adults.

scholarly journals Characterization and clinical implications of ankle impedance during walking in chronic stroke

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Amanda L. Shorter ◽  
James K. Richardson ◽  
Suzanne B. Finucane ◽  
Varun Joshi ◽  
Keith Gordon ◽  
...  
Keyword(s):  
Ankle Joint ◽  
Stance Phase ◽  
Clinical Care ◽  
Joint Stiffness ◽  
Mechanical Impedance ◽  
Chronic Stroke ◽  
Joint Mechanics ◽  
Clinical Assessments ◽  
Post Stroke ◽  
Joint Damping

AbstractIndividuals post-stroke experience persisting gait deficits due to altered joint mechanics, known clinically as spasticity, hypertonia, and paresis. In engineering, these concepts are described as stiffness and damping, or collectively as joint mechanical impedance, when considered with limb inertia. Typical clinical assessments of these properties are obtained while the patient is at rest using qualitative measures, and the link between the assessments and functional outcomes and mobility is unclear. In this study we quantify ankle mechanical impedance dynamically during walking in individuals post-stroke and in age-speed matched control subjects, and examine the relationships between mechanical impedance and clinical measures of mobility and impairment. Perturbations were applied to the ankle joint during the stance phase of walking, and least-squares system identification techniques were used to estimate mechanical impedance. Stiffness of the paretic ankle was decreased during mid-stance when compared to the non-paretic side; a change independent of muscle activity. Inter-limb differences in ankle joint damping, but not joint stiffness or passive clinical assessments, strongly predicted walking speed and distance. This work provides the first insights into how stroke alters joint mechanical impedance during walking, as well as how these changes relate to existing outcome measures. Our results inform clinical care, suggesting a focus on correcting stance phase mechanics could potentially improve mobility of chronic stroke survivors.

scholarly journals Multifunctional above-knee prosthesis for stairs' walking

1987 ◽  
Vol 11 (3) ◽  
pp. 139-145 ◽  
Author(s):  
K. Koganezawa ◽  
H. Fujimoto ◽  
I. Kato
Keyword(s):  
Knee Joint ◽  
Ankle Joint ◽  
Stance Phase ◽  
Knee Prosthesis ◽  
Power Sources ◽  
Stair Ascent ◽  
Level Walking ◽  
External Power ◽  
Leg Prosthesis ◽  
Full Body

The multifunctional above-knee prosthesis WLP-7R (Waseda Leg Prosthesis - type 7 Refined) described in this study allows amputees to descend and ascend stairs with no external power sources. With the hydraulic circuit mounted in the shank, the ankle joint and the knee joint mutually conterbalance during stance phase in stair walking as well as level walking so that the following performances are obtained. The yielding (flexing) of the knee joint is prevented and smooth advance from stance-phase to swing-phase is realized in level walking. The gradual yielding of the knee joint and the ankle joint while sustaining full body weight is realized in stair descent. Reciprocal stepping with sound and disabled legs during stair ascent is also realised although the powerful extension of the knee joint during stance phase is not possible. The performance of the WLP-7R was examined by a walking experiment in which amputees could descend and ascend the stairs as well as walk on a flat surface after approximately one hour's training.

Effect of prosthetic ankle units on the gait of persons with bilateral trans-femoral amputations

2008 ◽  
Vol 32 (1) ◽  
pp. 111-126 ◽  
Author(s):  
Lexyne L. McNealy ◽  
Steven A. Gard
Keyword(s):  
Power Generation ◽  
Range Of Motion ◽  
Ankle Joint ◽  
Lower Limb ◽  
Stance Phase ◽  
Sagittal Plane ◽  
The Body ◽  
Control Group ◽  
Initial Contact ◽  
Ankle Motion

In able-bodied individuals, the ankle joint functions to provide shock absorption, aid in foot clearance during the swing phase, and provides a rocker mechanism during stance phase to facilitate forward progression of the body. Prosthetic ankles currently used by persons with lower limb amputations provide considerably less function than their anatomical counterparts. However, increased ankle motion in the sagittal plane may improve the gait of persons with lower limb amputations while providing a more versatile prosthesis. The primary aim of this study was to examine and quantify temporal-spatial, kinematic, and kinetic changes in the gait of four male subjects with bilateral trans-femoral amputations who walked with and without prosthetic ankle units. Two prosthesis configurations were examined: (i) Baseline with only two Seattle LightFoot2 prosthetic feet, and (ii) with the addition of Endolite Multiflex Ankle units. Data from the gait analyses were compared between prosthetic configurations and with a control group of able-bodied subjects. The amputee subjects' freely-selected walking speeds, 0.74 ± 0.19 m/s for the Baseline condition and 0.81 ± 0.15 m/s with the ankle units, were much less than that of the control subjects (1.35 ± 0.10 m/s). The amputee subjects demonstrated no difference in walking speed, step length, cadence, or ankle, knee, and hip joint moments and powers between the two prosthesis configurations. Sagittal plane ankle range of motion, however, increased by 3–8° with the addition of the prosthetic ankle units. Compared to the control group, following initial contact the amputee subjects passively increased the rate of energy storage or dissipation at the prosthetic ankle joint, actively increased the power generation at the hip, and increased the extension moment at the hip while wearing the prosthetic ankle configuration. The amputee subjects increased the power generation at their hips, possibly as compensation for the reduced rate of energy return at their prosthetic ankles. Results from subject questionnaires administered following the gait analyses revealed that the prosthetic ankle units provided more comfort during gait and did not increase the perceived effort to walk. The subjects also indicated that they preferred walking with the prosthetic ankle units compared to the Baseline configuration. The results of the study showed that the prosthetic ankle units improved sagittal plane ankle range of motion and increased the comfort and functionality of the amputee subjects’ prostheses by restoring a significant portion of the ankle rocker mechanism during stance phase. Therefore, prosthetic ankle mechanisms should be considered a worthwhile option when prostheses are prescribed for persons with trans-femoral amputations.

scholarly journals The Function Axis of Rotation of the Ankle Joint during Simulated Gait

2017 ◽  
Vol 2 (3) ◽  
pp. 2473011417S0003
Author(s):  
Daniel Sturnick ◽  
Constantine Demetracopoulos ◽  
Guilherme Honda Saito
Keyword(s):  
Ankle Joint ◽  
Stance Phase ◽  
Force Plate ◽  
Implant Design ◽  
Joint Mechanics ◽  
Center Of Rotation ◽  
Axis Of Rotation ◽  
Ankle Kinematics ◽  
Flexion Extension ◽  
Joint Center

Category: Ankle, Ankle Arthritis, Hindfoot Introduction/Purpose: Implant component positioning is considered as an important factor in function and longevity in total ankle arthroplasty (TAA). However, accurate and repeatable positioning remains a limitation with current techniques and instrumentation. In addition, further investigation is needed to objectively define the optimum component positioning. Cadaveric gait simulation is a valuable tool for investigating foot and ankle joint mechanics during functional tasks such as the stance phase of gait. The objective of this study was to investigate the functional axis of rotation of the native ankle joint during simulated gait. Methods: The stance phase of healthy gait was simulated with six mid-tibia cadaveric specimens using a previously validated device and methodology. A robotic platform reproduced tibial-ground kinematics by moving a force plate relative to the stationary specimen while physiologic loads were applied to the extrinsic tendons to actuate the foot. (Figure 1A). Ankle kinematics were measured from reflective markers attached to the tibia and talus via surgical pins. The helical axes of rotation of the talus with respect to the tibia was calculated during three portions of stance: initial plantarflexion during earlier-stance after heal strike, dorsiflexion during mid-stance, and final plantarflexion during late-stance. The position and orientation of these kinematic-defined axes of rotation were compared to the transmalleolar axis and reduced to its anteroposterior position and transverse plane angle (Figure 1B). Results: Analyses revealed that ankle joint functional axis of rotation varied from the anatomic reference throughout stance. The kinematic center of rotation was located 16.4 ± 5.8 mm, 16.5 ± 6.6 mm, and 15.6 ± 6.5 mm anterior to the transmalleolar axis during early-, mid- and late-portions of stance, respectively. Conclusion: This study revealed that the position of the flexion-extension axis varies greatly between specimens during simulated gait. While previous reports have suggested that the transmalleolar axis is an acceptable approximation for the ankle joint center, these findings suggest that further research in warranted to better describe the complex tibiotalar kinematics. This work may provide future insight to guide implant design and advance techniques, to better place articular constraints of a total ankle in the native center of rotation of the joint.

Interpretation of Ankle Joint Moments during the Stance Phase of Walking: A Comparison of Two Orthogonal Axes Systems

2001 ◽  
Vol 17 (2) ◽  
pp. 173-180 ◽  
Author(s):  
Adrienne E. Hunt ◽  
Richard M. Smith
Keyword(s):  
Coordinate System ◽  
Ankle Joint ◽  
Stance Phase ◽  
Reaction Force ◽  
Frontal Plane ◽  
Transverse Plane ◽  
The Body ◽  
Global Coordinate System ◽  
Coordinate Systems ◽  
Joint Moments

Three-dimensional ankle joint moments were calculated in two separate coordinate systems, from 18 healthy men during the stance phase of walking, and were then compared. The objective was to determine the extent of differences in the calculated moments between these two commonly used systems and their impact on interpretation. Video motion data were obtained using skin surface markers, and ground reaction force data were recorded from a force platform. Moments acting on the foot were calculated about three orthogonal axes, in a global coordinate system (GCS) and also in a segmental coordinate system (SCS). No differences were found for the sagittal moments. However, compared to the SCS, the GCS significantly (p < .001) overestimated the predominant invertor moment at midstance and until after heel rise. It also significantly (p < .05) underestimated the late stance evertor moment. This frontal plane discrepancy was attributed to sensitivity of the GCS to the degree of abduction of the foot. For the transverse plane, the abductor moment peaked earlier (p < .01) and was relatively smaller (p < .01) in the GCS. Variability in the transverse plane was greater for the SCS, and attributed to its sensitivity to the degree of rearfoot inversion. We conclude that the two coordinate systems result in different calculations of nonsagittal moments at the ankle joint during walking. We propose that the body-based SCS provides a more meaningful interpretation of function than the GCS and would be the preferred method in clinical research, for example where there is marked abduction of the foot.

scholarly journals An Attempt to Improve Stance Mechanics of Trans-Tibial Amputee Gait by the Design of a Modular Ankle Joint Prosthetic

2018 ◽  
Author(s):  
Alastair B. During ◽  
Sudesh Sivarasu ◽  
George Vicatos
Keyword(s):  
Ankle Joint ◽  
Stance Phase ◽  
Gait Cycle ◽  
Joint Angle ◽  
Sagittal Plane ◽  
Low Cost ◽  
A Priori ◽  
Walking Gait ◽  
Compression Springs ◽  
Amputee Gait

A-priori research show that trans-tibial (TT) amputees display poor gait parameters when walking with passive mechanical ankle-foot prosthetics (AFP’s). This has large implications for the amputee populations in the developing world, who have limited access to advanced prosthetic technologies and instead rely on baseline AFP’s. Analysis of such baseline AFP’s in literature indicates that the predominant issue with these devices are their inability to adequately replicate the mechanics of a normal ankle during the stance phase of a walking gait cycle. This has shown to be a contributory cause of increased energy expenditure, as well as secondary complications such as osteoarthritis and joint deterioration. This paper presents the design and analysis of a modular low-cost ankle-joint prosthetic (AJP) that serves as an attachment to existing prosthetic feet, with the intention to improve the ankle mechanics thereof. The AJP is modelled to reproduce ankle joint mechanisms, specifically controlled relative angular flexion in the sagittal plane, using only simple mechanical elements (i.e. compression springs instead of electronics). Initial results were positive, indicating that the AJP improves the stance phase mechanics of the baseline AFP in a simulated TT amputee gait cycle. During forefoot dorsiflexion rollover, an 80%–132% (p < 0.001) increase in joint angle and a 42–56% decrease in ankle stiffness (p < 0.001 for all but one participant) is observed. Following heelstrike a 22%–77% (p < 0.001) increase in joint angle is observed. However equipment and methodology errors left the moment response of this phase unverifiable. The overall conclusion of this paper is that the introduction of the AJP to baseline AFP’s supplies evidence of improved rollover shapes, easier phase transitions, and the facilitation of footflat during mid-stance.

Dynamic Angular Stiffness of the Ankle Joint during Running and Sprinting

1998 ◽  
Vol 14 (3) ◽  
pp. 292-299 ◽  
Author(s):  
Darren J. Stefanyshyn ◽  
Benno M. Nigg
Keyword(s):  
Ankle Joint ◽  
Stance Phase ◽  
Dynamic Stiffness ◽  
The Moment ◽  
Relationship Of

The purpose of this study was to compare the moment-angle relationship of the ankle joint during running and sprinting to determine how the dynamic angular stiffness is influenced by different activities. For both running and sprinting, the results indicated that the ankle joint produced an exclusively extensor moment, absorbing energy during the first half of the stance phase and producing energy during the second half. The biphasic nature of the joint absorbing energy followed by the joint producing energy, while continually creating an extensor moment, was similar to a spring being compressed and allowed to extend. The dynamic stiffness of the ankle joint was 5.68 N · m/° for running and 7.38 N · m/° for sprinting. It appeared that the stiffness of the ankle joint was not a specialized characteristic of each individual but rather a specialized characteristic of the activity or demand placed upon it.

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