scholarly journals THE INFLUENCE OF HYDRAULIC ANKLES AND MICROPROCESSOR-CONTROL ON THE BIOMECHANICS OF TRANS-TIBIAL AMPUTEES DURING QUIET STANDING ON A 5° SLOPE

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Michael McGrath ◽  
Katherine C. Davies ◽  
Piotr Laszczak ◽  
Beata Rek ◽  
Joe McCarthy ◽  
...  
Keyword(s):  
Lower Limb ◽  
Reaction Force ◽  
Quiet Standing ◽  
Microprocessor Control ◽  
Prosthetic Foot ◽  
Prosthetic Limbs ◽  
Ankle Joints ◽  
Sound Side ◽  
Computer Controlled ◽  
Prosthetic Feet

BACKGROUND: Lower limb amputees have a high incidence of comorbidities, such as osteoarthritis, which are believed to be caused by kinetic asymmetries. A lack of prosthetic adaptation to different terrains requires kinematic compensations, which may influence these asymmetries. METHOD: Six SIGAM grade E-F trans-tibial amputees (one bilateral) wore motion capture markers while standing on force plates, facing down a 5° slope. The participants were tested under three prosthetic conditions; a fixed attachment foot (FIX), a hydraulic ankle (HYD) and a microprocessor foot with a ‘standing support’ mode (MPF). The resultant ground reaction force (GRF) and support moment for prosthetic and sound limbs were chosen as outcome measures. These were compared between prosthetic conditions and to previously captured able-bodied control data. RESULTS: The distribution of GRF between sound and prosthetic limbs was not significantly affected by foot type. However, the MPF condition required fewer kinematic compensations, leading to a reduction in sound side support moment of 59% (p=0.001) and prosthetic side support moment of 43% (p=0.02) compared to FIX. For the bilateral participant, only the MPF positioned the GRF vector anterior to the knees, reducing the demand on the residual joints to maintain posture. CONCLUSION: For trans-tibial amputees, loading on lower limb joints is affected by prosthetic foot technology, due to the kinematic compensations required for slope adaptation. MPFs with ‘standing support’ might be considered reasonable and necessary for bilateral amputees, or amputees with stability problems due to the reduced biomechanical compensations evident. LAYMAN’S ABSTRACT: Lower limb prostheses work well on flat ground but often don’t adapt well to uneven ground or slopes. As a result, amputees tend to put more of their weight through their healthy leg. This can lead to problems like back pain and arthritis. In this study, the posture and weight distribution of below knee amputees were analysed while they stood facing down a slope. They did this with three different prosthetic feet; one with no ‘ankle’ joint, one with an ‘ankle’ (which could always move) and one with a computer-controlled ‘ankle’ (which could adapt to the slope but then resist movement when the wearer was stood still). Changing the prosthetic feet did not affect the amount of weight put through each limb, but when they had ‘ankle’ joints, the amputees were able to stand up straight, with a better posture. This meant that the demand on their joints was reduced, particularly on the healthy limb. One participant had below knee amputations on both legs. For this participant, only the computer-controlled device allowed her to stand up straight and well balanced. Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/33517/25933 How to Cite: McGrath M, Davies KC, Laszczak P, Rek B, McCarthy J, Zahedi S, Moser D. The influence of hydraulic ankles and microprocessor-control on the biomechanics of trans-tibial amputees during quiet standing on a 5° slope. Canadian Prosthetics & Orthotics Journal. 2019;Volume2, Issue2, No.2. https://doi.org/10.33137/cpoj.v2i2.33517 CORRESPONDING AUTHOR Dr. Michael McGrath,Research Scientist–Clinical EvidenceBlatchford Group, Unit D Antura, Bond Close, Basingstoke, RG24 8PZ, United KingdomEmail: [email protected]: https://orcid.org/0000-0003-0195-970X  

Variability of kinetic variables during gait in unilateral transtibial amputees

2012 ◽  
Vol 36 (2) ◽  
pp. 225-230 ◽  
Author(s):  
Zdenek Svoboda ◽  
Miroslav Janura ◽  
Lee Cabell ◽  
Milan Elfmark
Keyword(s):  
Ground Reaction Force ◽  
Reaction Force ◽  
Heel Strike ◽  
Force Variability ◽  
Prosthetic Foot ◽  
Prosthetic Limbs ◽  
Prosthetic Feet ◽  
The Stability ◽  
Braking Phase ◽  
Transtibial Amputees

Background: Prosthetic gait increases demands on stability. Some variability measures can be used to investigate the stability of movement for prosthetic feet.Objectives: The purpose of this study was to determine the influence of the prosthetic foot on ground reaction force variability for transtibial amputee gait.Study Design: Comparative analysis.Methods: Eleven male unilateral transtibial amputees participated in this study. Each subject walked at self-selected speed with both conventional (SACH) and energy storing (Sureflex) feet. Time and ground reaction force variables and their coefficients of variation were calculated for each foot type and limb.Results: Mediolateral force variables had high variability for all conditions. The Sureflex had a larger variability than the SACH foot for the braking peak ( p < 0.05), which may have been caused by gait instability after the heel strike. There were significant differences between intact and prosthetic limbs in total loading (force impulses) with the SACH foot ( p < 0.05).Conclusions: The prosthetic foot and alignment issues related to the foot influence GRF variability. During the braking phase the SACH foot is characterized by higher variability in mediolateral direction and Sureflex by higher variability in anterior-posterior direction.Clinical relevanceDifferences in variability in ground reaction force variables can represent a person’s stability. Observing variability can contribute to better understanding of critical events in gait cycle with the use of various prosthetic feet.

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 EFFECTS OF A PROSTHETIC FOOT WITH INCREASED CORONAL ADAPTABILITY ON CROSS-SLOPE WALKING

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Björn Altenburg ◽  
Michael Ernst ◽  
Pawel Maciejasz ◽  
Thomas Schmalz ◽  
Frank Braatz ◽  
...  
Keyword(s):  
Lower Limb ◽  
Patient Reported Outcomes ◽  
Center Of Pressure ◽  
Reaction Force ◽  
Frontal Plane ◽  
Limb Amputation ◽  
The Novel ◽  
Perceived Safety ◽  
Prosthetic Foot ◽  
Patient Reported

BACKGROUND: Walking on cross-slopes is a common but challenging task for persons with lower limb amputation. The uneven ground and the resulting functional leg length discrepancy in this situation requires adaptability of both user and prosthesis. OBJECTIVE(S): This study investigated the effects of a novel prosthetic foot that offers adaptability on cross-slope surfaces, using instrumented gait analysis and patient-reported outcomes. Moreover, the results were compared with two common prosthetic feet.  METHODOLOGY: Twelve individuals with unilateral transtibial amputation and ten able-bodied control subjects participated in this randomized cross-over study. Participants walked on level ground and ±10° inclined cross-slopes at a self-selected walking speed. There were three prosthetic foot interventions: Triton Side Flex (TSF), Triton LP and Pro-Flex LP. The accommodation time for each foot was at least 4 weeks. The main outcome measures were as follows: frontal plane adaptation of shoe and prosthetic foot keel, mediolateral course of the center of pressure, ground reaction force in vertical and mediolateral direction, external knee adduction moment, gait speed, stance phase duration, step length and step width. Patient-reported outcomes assessed were the Activities Specific Balanced Confidence (ABC) scale, Prosthetic Limb Users Survey of Mobility (PLUS M) and Activities of Daily Living Questionnaire (ADL-Q).  FINDINGS: The TSF prosthetic foot adapted both faster and to a greater extent to the cross-slope conditions compared to the Triton LP and Pro-Flex LP. The graphs for the mediolateral center of pressure course and mediolateral ground reaction force showed a distinct grouping for level ground and ±10° cross-slopes, similar to control subjects. In the ADL-Q, participants reported a higher level of perceived safety and comfort when using the TSF on cross-slopes. Eight out of twelve participants preferred the TSF over the reference. CONCLUSION: The frontal plane adaptation characteristics of the TSF prosthetic foot appear to be beneficial to the user and thus may enhance locomotion on uneven ground – specifically on cross-slopes. Layman's Abstract Walking on cross-slopes is a common but challenging task for persons with lower limb amputation. The adaptability of prostheses is limited. Users alter gait strategies to cope with uneven ground. The prosthetic foot is a central component of a lower limb prosthesis. This study investigated if a novel prosthetic foot with greater adaptability is beneficial on cross-slopes. Twelve individuals with transtibial amputation (ITTAs) took part in the study. In addition, ten abled-bodied persons were measured as controls. The ITTAs were fitted with the novel foot and a reference foot. The accommodation time for each foot was four weeks at least. Afterwards gait data and patient-reported outcomes were assessed. The analyzed gait data showed clear differences in terrain compliance for the measured feet. The novel foot adapts both faster and to a greater extent to the cross-slope conditions. The self-reported outcome measures revealed better comfort and perceived safety when using the adaptive foot concept in comparison to the commercial reference. These results suggest that the adaptation characteristics of the novel foot concept are beneficial to the user. Thus, it may enhance locomotion on uneven ground such as cross-slopes. Article PDF Link: How To Cite: Altenburg B, Ernst M, Maciejasz P, Schmalz T, Braatz F, Gerke H, Bellmann M. Effects of a prosthetic foot with increased coronal adaptability on cross-slope walking. Canadian Prosthetics & Orthotics Journal. 2021;Volume 4, Issue 1, No.7.  https://doi.org/10.33137/cpoj.v4i1.35206 Corresponding Author: Björn Altenburg,Research Biomechanics, Ottobock SE & Co. KGaA, Göttingen, Germany.E-Mail: [email protected] ID: https://orcid.org/0000-0002-3484-4346  

Development of a Bimodal Ankle-Foot Prosthesis for Walking and Standing/Swaying

2013 ◽  
Vol 7 (3) ◽  
Author(s):  
Andrew H. Hansen ◽  
Eric A. Nickel
Keyword(s):  
Mechanical Properties ◽  
Lower Limb ◽  
Mechanical Stability ◽  
Balance Confidence ◽  
Prosthetic Foot ◽  
Human Ankle ◽  
Body Center ◽  
Impaired Balance ◽  
Prosthetic Feet ◽  
Lower Height

The human ankle-foot system conforms to a circular effective rocker shape for walking, but to a much flatter effective shape for standing and swaying. Many persons with lower limb amputations have impaired balance and reduced balance confidence, and may benefit from prostheses designed to provide flatter effective rocker shapes during standing and swaying tasks. This paper describes the development and testing of an ankle-foot prosthesis prototype that provides distinctly different mechanical properties for walking and standing/swaying. The prototype developed was a single-axis prosthetic foot with a lockable ankle for added stability during standing and swaying. The bimodal ankle-foot prosthesis prototype was tested on pseudoprostheses (walking boots with prosthetic feet beneath) for walking and standing/swaying loads, and was compared to an Otto Bock single-axis prosthetic foot and to able-bodied data collected in a previous study. The height-normalized radius of the effective rocker shape for walking with the bimodal ankle-foot prototype was equal to that found earlier for able-bodied persons (0.17); the standing and swaying effective shape had a lower height-normalized radius (0.70) compared with that previously found for able-bodied persons (1.11). The bimodal ankle-foot prosthesis prototype had a similar radius as the Otto Bock single-axis prosthetic foot for the effective rocker shape for walking (0.17 for both), but had a much larger radius for standing and swaying (0.70 for bimodal, 0.34 for single-axis). The results suggest that the bimodal ankle-foot prosthesis prototype provides two distinct modes, including a biomimetic effective rocker shape for walking and an inherently stable base for standing and swaying. The radius of the prototype's effective rocker shape for standing/swaying suggests that it may provide inherent mechanical stability to a prosthesis user, since the radius is larger than the typical body center of mass’s distance from the floor (between 50–60% of height). Future testing is warranted to determine if the bimodal ankle-foot prosthesis will increase balance and balance confidence in prosthesis users.

scholarly journals Gait Analysis Using Load-Controlled Single- and Split-Belt Treadmills

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 48
Author(s):  
Yo Ouchi ◽  
Nobutaka Tsujiuchi ◽  
Akihito Ito ◽  
Kiyoshi Hirose
Keyword(s):  
Lower Limb ◽  
Driving Force ◽  
Reaction Force ◽  
Constant Load ◽  
Lower Limb Muscles ◽  
Ankle Joints ◽  
Limb Muscles ◽  
The Difference ◽  
And Training ◽  
Ankle Joint Moment

We developed a self-paced load-controlled treadmill with two built-in force plates to enhance lower limb muscles. Since the load can be changed freely with a load-controlled treadmill, it can be widely utilized in fields such as rehabilitation and training. In this paper, we experimentally investigated the difference between single-belt and split-belt load-controlled treadmills with two subjects, who walked 30 s with a constant load r = 0, 5, 10, 15% based on the maximum driving force on both treadmills. Our result showed that the angular range of the motion of the ankle joints when walking on a single-belt treadmill was up to 2.68 times larger than walking on a split-belt treadmill. The ground reaction force reading showed that the ankle joint moment on a single-belt was larger during the terminal stance, suggesting that single-belt treadmills more effectively enhance lower limb muscles.

POSTURAL STABILITY STRATEGIES IN TRANSTIBIAL AMPUTEES DURING QUIET STANDING IN ALTERED SENSORY CONDITIONS WEARING THREE TYPES OF PROSTHETIC FEET

2020 ◽  
Vol 20 (02) ◽  
pp. 1950071
Author(s):  
NOORANIDA ARIFIN ◽  
NOOR AZUAN ABU OSMAN ◽  
SADEEQ ALI
Keyword(s):  
Postural Stability ◽  
Quiet Standing ◽  
Lateral Direction ◽  
Prosthetic Foot ◽  
Compliant Surface ◽  
Eyes Closed ◽  
Strong Positive Relationship ◽  
Movement Strategy ◽  
Prosthetic Feet ◽  
Transtibial Amputees

Individuals with transtibial amputation exhibit altered movement strategy to sustain stability during quiet standing due to reduced proprioception on the amputated limb. The aim of this study is to determine the movement strategies in anterior–posterior and medial–lateral directions in predicting the overall postural stability. In this crossover study, postural stability of ten transtibial amputees was assessed using computed posturography while wearing different prosthetic foot types: solid ankle cushion heel (SACH), single axis (SA) and energy storage and return (ESAR). Three stability indices were measured during four conditions: standing with eyes opened and closed, standing on compliant surface and standing with tilted head. From the standard multiple regression analysis, 63% to 99% of the OSI score in all sensory conditions were explained from the MLSI score, while 11% to 56% from the APSI score. The Pearson’s [Formula: see text] indicated significant strong positive relationship between OSI and MLSI [Formula: see text]–[Formula: see text] during all sensory conditions. The APSI score was significantly lower than OSI during eyes-closed and head extended conditions for all prosthetic feet [Formula: see text]. Adjustments in postural stability strategies in transtibial amputees mostly occurred in medial–lateral direction regardless of prosthetic feet types and altered sensory conditions.

scholarly journals Effects on ankle power and sound limb load with an active prosthetic foot

2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Eva Pröbsting ◽  
Björn Altenburg ◽  
Thomas Schmalz ◽  
Kerstin Krug
Keyword(s):  
Mechanical Work ◽  
Prosthetic Foot ◽  
Level Walking ◽  
Knee Loading ◽  
Sound Side ◽  
Strong Relation ◽  
Transfemoral Amputees ◽  
Prosthetic Feet ◽  
Power Outputs ◽  
Limb Load

AbstractThe performance of conventional prosthetic feet depends on material and construction principles. Certain powered feet can even generate net positive mechanical work in order to provide an active push-off. The aim of this study was to evaluate the influence of ankle power on the gait of transfemoral amputees. For this purpose level walking of six transfemoral amputees was analysed with a basic and an active foot and three different power settings of the latter. The results show clear advantages of the active foot in comparison with a basic foot. However, a strong relation of the sound side knee loading parameters with the varied ankle power outputs of the active foot couldn’t be shown.

scholarly journals Does Vertical Ground Reaction Force of the Hip, Knee, and Ankle Joints Change in Patients with Adolescent Idiopathic Scoliosis after Spinal Fusion?

2018 ◽  
Vol 12 (2) ◽  
pp. 349-355
Author(s):  
Mohd Imran Yusof ◽  
Shazlin Shaharudin ◽  
Prema Sivalingarajah
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Cobb Angle ◽  
Spinal Fusion ◽  
Lower Limb ◽  
Reaction Force ◽  
Vertical Ground Reaction Force ◽  
Significant Difference ◽  
Ankle Joints ◽  
Vertical Ground

<sec><title>Study Design</title><p>Comparative cross-sectional study.</p></sec><sec><title>Purpose</title><p>We measured the vertical ground reaction force (vGRF) of the hip, knee, and ankle joints during normal gait in normal patients, adolescent idiopathic scoliosis (AIS) patients with a Cobb angle &lt;40° and in AIS patients with spinal fusion. We aimed to investigate whether vGRF in the aforementioned joints is altered in these three groups of patients.</p></sec><sec><title>Overview of Literature</title><p>vGRF of the lower limb joints may be altered in these groups of patients. Although it is known that excessive force in the joints may induce early arthritis, there is limited relevant information in the literatures.</p></sec><sec><title>Methods</title><p>We measured vGRF of the hip, knee, and ankle joints during heel strike, early stance, mid stance, and toe-off phases in normal subjects (group 1, n=14), AIS patients with Cobb angle &lt;40° (group 2, n=14), and AIS patients with spinal fusion (group 3, n=13) using a gait analysis platform. Fifteen auto-reflective tracking markers were attached to standard anatomical landmarks in both the lower limbs. The captured motion images were used to define the orientations of the body segments and force exerted on the force plate using computer software. Statistical analysis was performed using independent t-test and analysis of variance to examine differences between the right and left sides as well as those among the different subject groups.</p></sec><sec><title>Results</title><p>The measurements during the four gait phases in all the groups did not show any significant difference (<italic>p</italic>&gt;0.05). In addition, no significant difference was found in the vGRF measurements of all the joints among the three groups (<italic>p</italic>&gt;0.05).</p></sec><sec><title>Conclusions</title><p>A Cobb angle &lt;40° and spinal fusion did not significantly create imbalance or alter vGRF of the lower limb joints in AIS patients.</p></sec>

scholarly journals Experimental characterization of the moment-angle curve during level and slope locomotion of transtibial amputee: Which parameters can be extracted to quantify the adaptations of microprocessor prosthetic ankle?

2021 ◽  
pp. 095441192110065
Author(s):  
Julie Davot ◽  
Marie Thomas-Pohl ◽  
Coralie Villa ◽  
Xavier Bonnet ◽  
Eric Lapeyre ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Lower Limb ◽  
Hydraulic Actuator ◽  
Period Range ◽  
Transtibial Amputation ◽  
Prosthetic Foot ◽  
Available Energy ◽  
Ankle Kinematics ◽  
Prosthetic Feet ◽  
The Moment

In case of transtibial amputation, the deficit resulting from the loss of the lower limb can be partly compensated with a prosthetic foot and adapted rehabilitation. New prosthetic feet have been developed for transtibial amputees to mimic ankle adaptability to varying terrain. Among them, Microprocessor Prosthetic Ankles (MPA) have a microprocessor to control an electric or a hydraulic actuator to adapt ankle kinematics in stairs and slopes. The objective is to investigate parameters extracted from the moment-angle curve (MAC) and use them to compare 3 MPA during level and slope locomotion against energy storing and return (ESR) foot. Five persons with lower limb transtibial amputation successively fitted with 3 MPA (Propriofoot™, Elan™, Meridium™) compared to their ESR foot. The participants had 2 weeks of adaptation before data acquisition and then a 3 week wash-out period. Range of motion, equilibrium point, hysteresis, late stance energy released, and quasi-stiffness were computed on level ground and 12% slope (upward and downward) thanks to the MAC at the ankle. The study shows the relevance of MAC parameters to evaluate the behavior of MPA. In particular, compared to ESR, all MPA tested in the present study demonstrated a better angle adaptation between walking conditions but a decrease of available energy for the propulsion. Among MPA, main results were: (i) for the Propriofoot™: an adaptation of the ankle angle without modification of the pattern of the MAC (ii) for the Elan™: a limited adaptation of the range of motion but a modification of the energy released (iii) for the Meridium™, the highest adaptation of the range of motion but the lowest available energy of propulsion. One of the main findings of the research is to show and quantify the relationship between range of motion and energy available when using different prosthetic feet in different walking conditions.

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