Prosthetic Gait Research Articles

Lower Extremity Prosthetic Gait Training: A Clinical Practice Guideline

The purpose of this guideline is to aggregate the available evidence on the elements and strategies of optimal prosthetic gait training for individuals with lower extremity amputation in the form of a succinct Clinical Practice Guideline.

하지절단자의 의지보행훈련 전·후 동적 균형 및 보행 능력에 대한 정량적 평가

본 연구는 재활공학연구소 통합재활프로그램에 참여한 하지절단자 16명을 대상으로 의지보행훈련 전·후 동적 균형 및 보행 능력의 변화를 비교분석하였다. 의지보행 훈련내용은 근력강화, 체중지지, 의지조절훈련, 균형능력강화, 체간안정화, 일상생활 강화훈련으로 구성되었다. 동적 균형능력은 functional reach test, L-test, 4 SS test를 실시하였고, 보행능력은 보행속도, 보폭과 보장비율을 측정하였다. 연구결과, 의지보행 훈련 후 functional reach test에서 이동거리가 평균 9.9% 증가하였으며(p.01), L-test와 4 SS test에서도 수행시간이 22.6%와 29.1% 각각 단축되었다. 또한 보행속도가 27.6% 빨라진 반면(p.01), 보폭과 보장비율의 유의한 변화는 없었다. 본 연구를 통해 하지절단자의 의지보행훈련 후 동적 균형 및 보행능력의 향상을 정량적으로 확인하였으며, 향후 절단자 재활훈련 프로그램 개선을 위한 기초자료로써 활용하고자 한다.

A Prototype of a Neural, Powered, Transtibial Prosthesis for the Cat: Benchtop Characterization.

We developed a prototype of a neural, powered, transtibial prosthesis for the use in a feline model of prosthetic gait. The prosthesis was designed for attachment to a percutaneous porous titanium implant integrated with bone, skin, and residual nerves and muscles. In the benchtop testing, the prosthesis was fixed in a testing rig and subjected to rhythmic vertical displacements and interactions with the ground at a cadence corresponding to cat walking. Several prosthesis functions were evaluated. They included sensing ground contact, control of transitions between the finite states of prosthesis loading, and a closed-loop modulation of the linear actuator gain in each loading cycle. The prosthetic design parameters (prosthesis length = 55 mm, mass = 63 g, peak extension moment = 1 Nm) corresponded closely to those of the cat foot-ankle with distal shank and the peak ankle extension moment during level walking. The linear actuator operated the prosthetic ankle joint using inputs emulating myoelectric activity of residual muscles. The linear actuator gain was modulated in each cycle to minimize the difference between the peak of ground reaction forces (GRF) recorded by a ground force sensor and a target force value. The benchtop test results demonstrated a close agreement between the GRF peaks and patterns produced by the prosthesis and by cats during level walking.

Comparing Gait with Multiple Physical Asymmetries Using Consolidated Metrics.

Physical changes such as leg length discrepancy, the addition of a mass at the distal end of the leg, the use of a prosthetic, and stroke frequently result in an asymmetric gait. This paper presents a metric that can potentially serve as a benchmark to categorize and differentiate between multiple asymmetric bipedal gaits. The combined gait asymmetry metric (CGAM) is based on modified Mahalanobis distances, and it utilizes the asymmetries of gait parameters obtained from motion capture and force data recorded during human walking. The gait parameters that were used in this analysis represent spatio-temporal, kinematic, and kinetic parameters. This form of a consolidated metric will help researchers identify overall gait asymmetry by showing them if the overall gait symmetry is improving and avoid the case where one parameter's symmetry is improving while another is getting worse. The CGAM metric successfully served as a measure for overall symmetry with eleven different gait parameters and successfully showed differences among gait with multiple physical asymmetries. The results showed that mass at the distal end had a larger magnitude on overall gait asymmetry compared to leg length discrepancy. It also showed that the combined effects are varied based on the cancelation effect between gait parameters. The metric was also successful in delineating the differences of prosthetic gait and able-bodied gait at three different walking velocities.

Modelagem e simulação da marcha protética usando modelo em 3D de uma prótese transtibial

O número de amputados no mundo, incluída a Colômbia, é de mais de dez milhões de pessoas, sendo a amputação abaixo do joelho, ou amputação transtibial, bastante recorrente. Devido às mudanças siológicas que se apresentam nos amputados transtibiais, a mecânica da marcha vê-se alterada e pode chegar a afetar signi cativamente a mobilidade do sujeito. Com o objetivo de conhecer o comportamento dinâmico dos amputados transtibiais, e gerar conhecimento para entender a conduta biomecânica deles e assim ajudar no processo de reabilitação física destes sujeitos, se propôs estudar a marcha protética desde simulações geradas de um modelo computacional. Para isso, construiu-se um modelo da marcha humana fazendo uso do intercâmbio de energia que se apresenta neste movimento, empregando a análise de Lagrange. Também se obteve a modelagem matemática (diagrama de bloques) de uma prótese transtibial ativa a partir do desenho em 3D realizado no software Solidworks®; este modelo se processou em Matlab® com o objetivo de emular o uso da prótese. No modelo da marcha normal obtido se substituiu uma das pernas pelo modelo da prótese para observar a marcha protética. Os resultados do modelo tanto em valores dos rangos articulares quanto em parâmetros espaço-temporais se encontram acordes com o observado em outros estudos. A análise cinemática do comportamento do modelo mostra que a prótese proporciona suporte o corpo e permite a marcha em ausência do segmento corporal, devido a que os dados obtidos pelo modelo de patrão da marcha concordam com os dados existentes em literatura. Esta proposta de simulação é uma ajuda para assegurar a aprendizagem do estudante e do médico respeito ao comportamento biomecânico da marcha protética, uma vez que nos últimos anos se tem visto e comprovado a utilidade do uso generalizado de simulações no âmbito médico.

Method for Predicting Deformation Characteristics of Prosthetic Feet

ABSTRACT Introduction Although clinical studies have found that individuals with amputation prefer prosthetic feet that provide energy return, biomechanical studies investigating these findings have been mixed. The objective of this study was to develop a method that predicts the deformation of a prosthetic foot during a standardized loading profile representing gait. The specific aim was to provide insight into the timing aspects of mechanical properties influenced by features of the device. Materials and Methods Mechanical properties were measured from a series of force-deflection curves obtained at specific loads and shank angles extracted from a standard dataset used in ISO22675. Five commercially available prosthetic feet with differing design features and structural properties were analyzed to provide the predicted vertical deflection as a function of normalized stance time. Results The method successfully identified differences in features across different designs and across differing weight classes of a similar design. Furthermore, it was observed that in most specimens tested, the predicted peak displacement did not occur at the peak loading. In the heel, peak displacement led the peak force, whereas in the forefoot, peak displacement lagged the peak force. The observations of heel displacement lead and forefoot displacement lag reflect the nonlinear mechanical characteristics of these devices and the complex loading expected during gait. Conclusion The method extends those currently used by describing deformation throughout stance and predicting temporal aspects of prosthetic foot mechanical properties related to loading during prosthetic gait. Future studies should address how individual user loading characteristics affect these measurements.

Energy flow analysis of amputee walking shows a proximally-directed transfer of energy in intact limbs, compared to a distally-directed transfer in prosthetic limbs at push-off

Reduced capacity and increased metabolic cost of walking occurs in amputees, despite advances in prosthetic componentry. Joint powers can quantify deficiencies in prosthetic gait, but do not reveal how energy is exchanged between limb segments. This study aimed to quantify these energy exchanges during amputee walking.Optical motion and forceplate data collected during walking at a self-selected speed for cohorts of 10 controls, 10 unilateral trans-tibial, 10 unilateral trans-femoral and 10 bilateral trans-femoral amputees were used to determine the energy exchanges between lower limb segments.At push-off, consistent thigh and shank segment powers were observed between amputee groups (1.12W/kg vs. 1.05W/kg for intact limbs and 0.97W/kg vs. 0.99W/kg for prosthetic limbs), and reduced prosthetic ankle power, particularly in trans-femoral amputees (3.12W/kg vs. 0.87W/kg). Proximally-directed energy exchange was observed in the intact limbs of amputees and controls, while prosthetic limbs displayed distally-directed energy exchanges at the knee and hip.This study used energy flow analysis to show a reversal in the direction in which energy is exchanged between prosthetic limb segments at push-off. This reversal was required to provide sufficient energy to propel the limb segments and is likely a direct result of the lack of push-off power at the prosthetic ankle, particularly in trans-femoral amputees, and leads to their increased metabolic cost of walking.

Poster 89 Functional Outcomes with Acute Inpatient Prosthetic Gait Training for Lower Extremity Amputees.

PM&RVolume 8, Issue 9S p. S190-S190 Poster Presentation Poster 89 Functional Outcomes with Acute Inpatient Prosthetic Gait Training for Lower Extremity Amputees Prateek Grover MD, PhD, Prateek Grover MD, PhD Washington University/BJH/SLCH Consortium, St Louis, MO, United StatesSearch for more papers by this authorOksana Volshteyn MD, Oksana Volshteyn MD Washington University/BJH/SLCH Consortium, St Louis, MO, United StatesSearch for more papers by this authorAmy Son PT, DPT, Amy Son PT, DPT Washington University/BJH/SLCH Consortium, St Louis, MO, United StatesSearch for more papers by this author Prateek Grover MD, PhD, Prateek Grover MD, PhD Washington University/BJH/SLCH Consortium, St Louis, MO, United StatesSearch for more papers by this authorOksana Volshteyn MD, Oksana Volshteyn MD Washington University/BJH/SLCH Consortium, St Louis, MO, United StatesSearch for more papers by this authorAmy Son PT, DPT, Amy Son PT, DPT Washington University/BJH/SLCH Consortium, St Louis, MO, United StatesSearch for more papers by this author First published: 24 September 2016 https://doi.org/10.1016/j.pmrj.2016.07.132Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume8, Issue9S2016 AAPM&R Annual Assembly AbstractsSeptember 2016Pages S190-S190 RelatedInformation

The significance of prosthetic gait training program for lower extremity amputees

The significance of prosthetic gait training program for lower extremity amputees

The dead spot phenomenon in prosthetic gait: Quantified with an analysis of center of pressure progression and its velocity in the sagittal plane

BackgroundThe “dead spot” phenomenon in prosthetics is a disruption in forward progression observed in the rearfoot of passive prosthetic foot-ankle systems which results in a compensatory and inefficient gait pattern by amputees. A metric to quantify the dead spot as a kinetic event has not yet been introduced. The present study implements a three-part metric to evaluate the dead spot in terms of time, magnitude, and total area using center of pressure velocity and a novel threshold value calculation. MethodsThe metrics are implemented for proof of efficacy using a convenient sample of four amputees (2 transtibial, 2 transfemoral) who walked in a 3D motion capture system with integrated force plates over five foot conditions. Findings“Continuous-lever” feet designs showed the most favorable metric results between subjects (p<0.05) and in an ad hoc analysis compared to an ideal foot condition within subjects (p>0.05). Ten of 18 (55.6%) foot conditions found to be similar to the ideal were continuous-lever feet. Lack of significant similarity between the feet and ideal conditions (1 of 18, 5.6%) were found in transfemoral subjects. InterpretationThe metric calculations were able to show statistical difference among foot conditions between subjects. One foot (continuous-lever, glass composite) had no detectable dead spot in the transtibial subjects. The lack of significant findings in transfemoral subjects indicates a different coefficient in threshold calculations may be more appropriate for these subjects versus transtibial subjects. Further research with larger sample is needed to determine clinically significant findings among feet and between transtibial and transfemoral subjects.

日常生活環境における大腿義足歩行の主要な下肢関節回転運動パターンの解析

日常生活環境における大腿義足歩行の主要な下肢関節回転運動パターンの解析

Quantifying prosthetic gait deviation using simple outcome measures.

To develop a subset of simple outcome measures to quantify prosthetic gait deviation without needing three-dimensional gait analysis (3DGA). Eight unilateral, transfemoral amputees and 12 unilateral, transtibial amputees were recruited. Twenty-eight able-bodied controls were recruited. All participants underwent 3DGA, the timed-up-and-go test and the six-minute walk test (6MWT). The lower-limb amputees also completed the Prosthesis Evaluation Questionnaire. Results from 3DGA were summarised using the gait deviation index (GDI), which was subsequently regressed, using stepwise regression, against the other measures. Step-length (SL), self-selected walking speed (SSWS) and the distance walked during the 6MWT (6MWD) were significantly correlated with GDI. The 6MWD was the strongest, single predictor of the GDI, followed by SL and SSWS. The predictive ability of the regression equations were improved following inclusion of self-report data related to mobility and prosthetic utility. This study offers a practicable alternative to quantifying kinematic deviation without the need to conduct complete 3DGA.

義足療法を用いた脳卒中の歩行再建の試み

義足療法を用いた脳卒中の歩行再建の試み

Poster 216 Hydraulic Prosthetic Gait Training with Contralateral Limb Fusion: A Case Report

Poster 216 Hydraulic Prosthetic Gait Training with Contralateral Limb Fusion: A Case Report

Assessing a low-cost accelerometer-based technique to estimate spatial gait parameters of lower-limb prosthesis users.

Inexpensive methods for characterizing lower-limb prosthetic gait allow clinicians to monitor gait quality. This study assessed an established method for estimating step length using a low-cost accelerometer to estimate distance walked in lower-limb prosthesis users and explore the use of subject-specific correction factors. A three-axis accelerometer was attached to participants using straps. Validity and test-retest reliability of step length was assessed in able-bodied individuals using a motion capture system. Validity of distance walked was assessed with lower-limb prosthesis users. A regression equation was developed for prosthesis users to estimate a correction factor that minimized error. The system demonstrated excellent reliability and minimal mean error for both participant groups, but subject-specific correction factors did not provide substantial benefit. Estimate variability was high, suggesting the need for further refinement. Estimating distance walked and step length from low-cost accelerometers may be a valid, clinically accessible method for characterizing prosthetic gait. The use of a low-cost accelerometer may provide valid means for estimating step length and distance walked of lower-limb prosthesis users in a clinical environment for monitoring patient outcomes.

計算モデル化および力・モーメントの主成分の分析に基づく大腿義足歩行解析

計算モデル化および力・モーメントの主成分の分析に基づく大腿義足歩行解析

Gaitography applied to prosthetic walking.

During walking on an instrumented treadmill with an embedded force platform or grid of pressure sensors, center-of-pressure (COP) trajectories exhibit a characteristic butterfly-like shape, reflecting the medio-lateral and anterior-posterior weight shifts associated with alternating steps. We define "gaitography" as the analysis of such COP trajectories during walking (the "gaitograms"). It is currently unknown, however, if gaitography can be employed to characterize pathological gait, such as lateralized gait impairments. We therefore registered gaitograms for a heterogeneous sample of persons with a trans-femoral and trans-tibial amputation during treadmill walking at a self-selected comfortable speed. We found that gaitograms directly visualize between-person differences in prosthetic gait in terms of step width and the relative duration of prosthetic and non-prosthetic single-support stance phases. We further demonstrated that one should not only focus on the gaitogram's shape but also on the time evolution along that shape, given that the COP evolves much slower in the single-support phase than in the double-support phase. Finally, commonly used temporal and spatial prosthetic gait characteristics were derived, revealing both individual and systematic differences in prosthetic and non-prosthetic step lengths, step times, swing times, and double-support durations. Because gaitograms can be rapidly collected in an unobtrusive and markerless manner over multiple gait cycles without constraining foot placement, clinical application of gaitography seems both expedient and appealing. Studies examining the repeatability of gaitograms and evaluating gaitography-based gait characteristics against a gold standard with known validity and reliability are required before gaitography can be clinically applied.

Stepping Asymmetry Among Individuals With Unilateral Transtibial Limb Loss Might Be Functional in Terms of Gait Stability

The asymmetry in step length in prosthetic gait is often seen as a detrimental effect of the impairment; however, this asymmetry also might be a functional compensation. An advantage of a smaller step length of the nonprosthetic leg, and specifically foot forward placement (FFP), might be that it will bring the center of mass closer to the base of support of the leading foot and thus increase the backward margin of stability (BW MoS). The purpose of this study was to characterize differences in step length, FFP, and the concomitant difference in BW MoS between steps of the prosthetic and nonprosthetic legs (referred to as prosthetic and nonprosthetic steps, respectively) of people after transtibial amputation. This was an observational and cross-sectional study. Ten people after transtibial amputation walked for 4 minutes on a self-paced treadmill. Step length and FFP were calculated at initial contact. The size of the BW MoS was calculated for the moment of initial contact and at the end of the double-support phase of gait. Step length (5.4%) and FFP (7.9%) were shorter for the nonprosthetic step than for the prosthetic step. The BW MoS at initial contact was larger for the nonprosthetic step, but because of a significant leg × gait event interaction effect, BW MoS did not differ significantly at the end of the double-support phase. All participants were relatively good walkers (score of E on the Special Interest Group in Amputee Medicine [SIGAM] scale). The smaller step length and FFP of the nonprosthetic step help to create a larger BW MoS at initial contact for the nonprosthetic step compared with the prosthetic step. Hence, step length asymmetry in people after transtibial amputation might be seen as a functional compensation to preserve BW MoS during the double-support phase to cope with the limited push-off power of the prosthetic ankle.

Prosthetic gait asymmetry when walking on an inclined treadmill

Background. Step length asymmetry is considered exclusive for measuring gait asymmetry. However asymmetries in trunk progression and forward foot placement relative to the trunk may also contribute to gait asymmetry since the sum of the two should result in step length asymmetry. This relation can be tested in a situation where increased propulsion demands are required such as in inclined walking. Especially prosthetic gait may magnify this relation since prosthetic gait is often asymmetric. Objective. To investigate the effect of inclination on (i) the relation between step length, trunk progression and forward foot placement asymmetry, and (ii) the adaptation strategies adopted by amputees to cope with altered propulsion demands. Methods. Full-body motion analysis was performed on 8 unilateral trans-tibial amputees when walking on an inclined treadmill at their comfortable speed. (Non-)Prosthetic, step length, trunk progression, forward foot placement and corresponding asymmetries were determined. Results. The asymmetries in both trunk progression plus forward foot placement were highly correlated to step length asymmetry for inclined walking. Adaptations were most prominent in forward foot placement. Inclination was negatively correlated with the average forward foot placement and positively correlated with the absolute differences in forward foot placement between the prosthetic and the non-prosthetic step. Two groups could be distinguished when looking at the direction (negative/positive) of forward foot placement asymmetry. When accounted for these groups, inclination was positively correlated to forward foot placement asymmetry. Conclusion. (i) The relation between asymmetries in step length, trunk progression and forward foot placement was unaffected by inclination. (ii) One adaptation strategy was to decreased non-prosthetic forward foot placement, however more subtle adaptations may also have played a role.

An animal model to evaluate skin–implant–bone integration and gait with a prosthesis directly attached to the residual limb

BackgroundDespite the number of advantages of bone-anchored prostheses, their use in patients is limited due to the lack of complete skin–implant integration. The objective of the present study was to develop an animal model that would permit both detailed investigations of gait with a bone-anchored limb prosthesis and histological analysis of the skin–implant–bone interface after physiological loading of the implant during standing and walking. MethodsFull-body mechanics of walking in two cats were recorded and analyzed before and after implantation of a percutaneous porous titanium pylon into the right tibia and attachment of a prosthesis. The rehabilitation procedures included initial limb casting, progressively increasing loading on the implant, and standing and locomotor training. Detailed histological analysis of bone and skin ingrowth into implant was performed at the end of the study. FindingsThe two animals adopted the bone-anchored prosthesis for standing and locomotion, although loads on the prosthetic limb during walking decreased by 22% and 62%, respectively, 4months after implantation. The animals shifted body weight to the contralateral side and increased propulsion forces by the contralateral hindlimb. Histological analysis of the limb implants demonstrated bone and skin ingrowth. InterpretationThe developed animal model to study prosthetic gait and tissue integration with the implant demonstrated that porous titanium implants may permit bone and skin integration and prosthetic gait with a bone-anchored prosthesis. Future studies with this model will help optimize the implant and prosthesis properties.