Feasibility of a Powered Knee Joint in Providing Stance and Swing Phase Knee Flexion when Using a Knee-Ankle-Foot Orthosis

2017 ◽  
Vol 29 (4) ◽  
pp. 177-182
Author(s):  
Masoud Rafiaei ◽  
Mokhtar Arazpour ◽  
Mahmood Bahramizadeh ◽  
Farzam Farahmand ◽  
Nima Jamshidi ◽  
...  
Keyword(s):  
Knee Joint ◽  
Knee Flexion ◽  
Swing Phase ◽  
Ankle Foot Orthosis ◽  
Foot Orthosis

The influence of a powered knee–ankle–foot orthosis on walking in poliomyelitis subjects: A pilot study

2015 ◽  
Vol 40 (3) ◽  
pp. 377-383 ◽  
Author(s):  
Mokhtar Arazpour ◽  
Alireza Moradi ◽  
Mohammad Samadian ◽  
Mahmood Bahramizadeh ◽  
Mahmoud Joghtaei ◽  
...  
Keyword(s):  
Knee Joint ◽  
Knee Flexion ◽  
Stance Phase ◽  
Step Length ◽  
Gait Pattern ◽  
Swing Phase ◽  
Ankle Foot Orthosis ◽  
Active Flexion ◽  
Locked Knee ◽  
Foot Orthosis

Background:Traditionally, the anatomical knee joint is locked in extension when walking with a conventional knee–ankle–foot orthosis. A powered knee–ankle–foot orthosis was developed to provide restriction of knee flexion during stance phase and active flexion and extension of the knee during swing phase of gait.Objective:The purpose of this study was to determine differences of the powered knee–ankle–foot orthosis compared to a locked knee–ankle–foot orthosis in kinematic data and temporospatial parameters during ambulation.Study design:Quasi—experimental design.Methods:Subjects with poliomyelitis (n = 7) volunteered for this study and undertook gait analysis with both the powered and the conventional knee–ankle–foot orthoses. Three trials per orthosis were collected while each subject walked along a 6-m walkway using a calibrated six-camera three-dimensional video-based motion analysis system.Results:Walking with the powered knee–ankle–foot orthosis resulted in a significant reduction in both walking speed and step length (both 18%), but a significant increase in stance phase percentage compared to walking with the conventional knee–ankle–foot orthosis. Cadence was not significantly different between the two test conditions ( p = 0.751). There was significantly higher knee flexion during swing phase and increased hip hiking when using the powered orthosis.Conclusion:The new powered orthosis permitted improved knee joint kinematic for knee–ankle–foot orthosis users while providing knee support in stance and active knee motion in swing in the gait cycle. Therefore, the new powered orthosis provided more natural knee flexion during swing for orthosis users compared to the locked knee–ankle–foot orthosis.Clinical relevanceThis orthosis has the potential to improve knee joint kinematics and gait pattern in poliomyelitis subjects during walking activities.

Ankle–foot orthosis with dorsiflexion resistance using spring-cam mechanism increases knee flexion in the swing phase during walking in stroke patients with hemiplegia

2020 ◽  
Vol 81 ◽  
pp. 27-32 ◽  
Author(s):  
Yusuke Sekiguchi ◽  
Dai Owaki ◽  
Keita Honda ◽  
Kenichiro Fukushi ◽  
Noriyoshi Hiroi ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Swing Phase ◽  
Stroke Patients ◽  
Ankle Foot Orthosis ◽  
Cam Mechanism ◽  
Foot Orthosis

scholarly journals Evaluation of gait symmetry in poliomyelitis subjects: Comparison of a conventional knee–ankle–foot orthosis and a new powered knee–ankle–foot orthosis

2016 ◽  
Vol 40 (6) ◽  
pp. 689-695 ◽  
Author(s):  
Mokhtar Arazpour ◽  
Fardin Ahmadi ◽  
Mahmood Bahramizadeh ◽  
Mohammad Samadian ◽  
Mohammad Ebrahim Mousavi ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Stance Phase ◽  
Swing Phase ◽  
Step Width ◽  
Gait Symmetry ◽  
Ankle Foot Orthosis ◽  
Swing Time ◽  
Locked Knee ◽  
Stance Time ◽  
Foot Orthosis

Background:Compared to able-bodied subjects, subjects with post-polio syndrome and poliomyelitis demonstrate a preference for weight-bearing on the non-paretic limb, causing gait asymmetry.Objectives:The purpose of this study was to evaluate the gait symmetry of the poliomyelitis subjects when ambulating with either a drop-locked knee–ankle–foot orthosis or a newly developed powered knee–ankle–foot orthosis.Study design:Quasi experimental study.Methods:Seven subjects with poliomyelitis who routinely wore conventional knee–ankle–foot orthoses participated in this study and received training to enable them to ambulate with the powered knee–ankle–foot orthosis on level ground, prior to gait analysis.Results:There were no significant differences in the gait symmetry index of step length ( p = 0.085), stance time ( p = 0.082), double-limb support time ( p = 0.929), or speed of walking ( p = 0.325) between the two test conditions. However, using the new powered knee–ankle–foot orthosis improved the symmetry index in step width ( p = 0.037), swing time ( p = 0.014), stance phase percentage ( p = 0.008), and knee flexion during swing phase ( p ⩽ 0.001) compared to wearing the drop-locked knee–ankle–foot orthosis.Conclusion:The use of a powered knee–ankle–foot orthosis for ambulation by poliomyelitis subjects affects gait symmetry in the base of support, swing time, stance phase percentage, and knee flexion during swing phase.Clinical relevanceA new powered knee–ankle–foot orthosis can improve gait symmetry for poliomyelitis subjects by influencing step width, swing time, stance time percentage, and knee flexion during swing phase when compared to ambulating with a drop-locked knee–ankle–foot orthosis.

Development of a Dynamic Knee Actuator for a KAFO Using Superelastic Alloys

2014 ◽  
Author(s):  
Feng Tian ◽  
Mohamed Samir Hefzy ◽  
Mohammad Elahinia
Keyword(s):  
Knee Joint ◽  
Gait Cycle ◽  
Swing Phase ◽  
Walking Ability ◽  
Knee Motion ◽  
Walking Gait ◽  
Ankle Foot Orthosis ◽  
Stance Control ◽  
In Series ◽  
Foot Orthosis

A knee-ankle-foot orthosis (KAFO), which covers the knee, ankle and foot, can mitigate abnormal walking pattern caused by weak quadriceps. Several types of KAFOs are currently available in the market: passive KAFOs, stance-control KAFOs and dynamic KAFOs. In passive KAFOs, the knee joint keeps being locked during standing and walking, and can be unlocked manually to allow free rotation for sitting. Stance-control KAFOs (SCKAFOs) allow free knee motion during swing phase when the braced leg is unloaded. Dynamic KAFOs are able to reproduce normal walking ability throughout whole gait cycle. This research is directed at using superelastic alloys to develop a dynamic knee actuator that can be mounted on a traditional passive KAFO. The actuator stiffness can match that of a normal knee joint during the walking gait cycle. This proposed knee actuator utilizes a storing-releasing energy method to apply functional compensation to the knee joint, controlling the knee joint during both stance and swing phases. Fundamentally, the knee actuator is composed of two distinct parts which are connected with the thigh and shank segments, respectively. There are two superelastic actuators that are housed within these two parts and activated independently. Each actuator is developed by combining a superelastic rod and a rotary spring in series. When neither actuator is engaged, the knee joint is allowed to rotate freely. The stance actuator works only in the stance phase and the swing actuator is active for the swing phase. The conceptual design of the knee actuator is verified using numerical simulation and a prototype is developed through additive manufacturing for confirming the concept.

scholarly journals EFFECT OF KINETIC RETURN ANKLE FOOT ORTHOSIS IN PATIENT WITH INCOMPLETE SPINAL CORD INJURY: CHANGES OF THE GAIT PATTERN. A CASE REPORT

2016 ◽  
Vol 2 (101) ◽  
pp. 8-16
Author(s):  
Margot Bergmann ◽  
Mari Alvela ◽  
Priit Eelmäe ◽  
Doris Vahtrik ◽  
Helena Gapeyeva
Keyword(s):  
Spinal Cord ◽  
Knee Joint ◽  
Ankle Joint ◽  
Gait Pattern ◽  
Swing Phase ◽  
Initial Contact ◽  
Ankle Foot Orthosis ◽  
Foot Progression Angle ◽  
Cord Injury ◽  
Foot Orthosis

Background. The variety of orthotics available induces a purpose for estimation of their influence of functional mobility for individual needs in people with incomplete spinal cord injuries (ISCI). The aim of the study was to investigate the effect of the use of kinetic return ankle foot orthosis (KRAFO) on gait pattern in case of ISCI. Methods. Ankle and knee joint kinematic and kinetic characteristics during gait with and without KRAFO were studied in a 34-year-old man with ISCI (fracture v.C5) using 3D motion analysis system (Vicon Motion Systems Ltd., UK) including two dynamographic platforms (AMTI, USA). Ankle and knee joint angles at initial contact and mid-stance, ankle dorsiflexion and foot progression angle in swing phase and ankle joint push-off values in stance phase were analysed. Results. An excessive dorsiflexion in right ankle joint at initial contact, in mid-stance and in swing-phase occurred when walking without the orthosis, which decreased (105, 57 and 73%, respectively, p < .01) with the use of KRAFO. Orthoses use evoked the decrease (77%, p < .01) in peak foot progression angle. Ankle joint peak push- off power was low without the use of KRAFO and decreased even more (28%, p < .05) with the use of orthosis. Decreases of knee joint flexion angle at initial contact and in mid-stance (29 and 23%, respectively) with the use of KRAFO were not significant as compared to gait without orthosis. Conclusions. Walking with KRAFO improved ankle and knee joint stability, providing a decrease in ankle kinematic characteristics but ankle joint push-off power did not change. Further studies are needed to compare the effect of KRAFO in comparison with other orthoses on gait pattern in case of ISCI in accordance with the patient- centric approach for rehabilitation process management.

Loads on the uprights of a knee-ankle-foot orthosis

2011 ◽  
Vol 35 (1) ◽  
pp. 106-112 ◽  
Author(s):  
KA Bernhardt ◽  
KR Kaufman
Keyword(s):  
Knee Joint ◽  
Knee Flexion ◽  
Sagittal Plane ◽  
Case Series ◽  
Case Description ◽  
Ankle Foot Orthosis ◽  
Component Design ◽  
Load Sensor ◽  
Design Case ◽  
Foot Orthosis

Background: Objective design criteria for orthotic components is lacking. This paucity of data results in prescription guidelines based on assumptions or practitioners' past experience, and the potential for incorrectly designed components. The purpose of this study was to directly measure loads on the knee joint of a knee-ankle-foot orthosis.Study design: Case series.Case Description and Methods: Three subjects who had been prescribed a knee-ankle-foot orthosis for quadriceps weakness underwent gait analysis and orthotic upright load data collection. A load sensor to measure the three force and three moment components was used in place of the lateral knee joint while the subjects walked in three knee flexion positions.Findings and Outcomes: Forces were highest in compression and moments were greatest in the sagittal plane. The kinetics did not increase solely with patient weight. There was substantial variability between subjects.Conclusions: This data will help guide orthotic component design and prescription guidelines. Knowledge of loading conditions will lead to more optimal orthotic intervention for patients and increased patient satisfaction.Clinical relevanceThis study is one of the first to directly measure loads on the upright of a KAFO. These data provide objective targets for engineering design. The data from this small case series can also be used to establish guidelines for patient device selection.

Defining the Mechanical Properties of a Spring-hinged Ankle Foot Orthosis to Assess its Potential Use in Children With Spastic Cerebral Palsy

2014 ◽  
Vol 30 (6) ◽  
pp. 728-731 ◽  
Author(s):  
Yvette L. Kerkum ◽  
Merel-Anne Brehm ◽  
Annemieke I. Buizer ◽  
Josien C. van den Noort ◽  
Jules G. Becher ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cerebral Palsy ◽  
Knee Flexion ◽  
Spastic Cerebral Palsy ◽  
Gait Performance ◽  
Ankle Foot Orthosis ◽  
The Moment ◽  
Potential Use ◽  
Foot Orthosis ◽  
Walking Energy Cost

A rigid ventral shelf ankle foot orthosis (AFO) may improve gait in children with spastic cerebral palsy (SCP) whose gait is characterized by excessive knee flexion in stance. However, these AFOs can also impede ankle range of motion (ROM) and thereby inhibit push-off power. A more spring-like AFO can enhance push-off and may potentially reduce walking energy cost. The recent development of an adjustable spring-hinged AFO now allows adjustment of AFO stiffness, enabling tuning toward optimal gait performance. This study aims to quantify the mechanical properties of this spring-hinged AFO for each of its springs and settings. Using an AFO stiffness tester, two AFO hinges and their accompanying springs were measured. The springs showed a stiffness range of 0.01−1.82 N·m·deg−1. The moment-threshold increased with increasing stiffness (1.13–12.1 N·m), while ROM decreased (4.91–16.5°). Energy was returned by all springs (11.5–116.3 J). These results suggest that the two stiffest available springs should improve joint kinematics and enhance push-off in children with SCP walking with excessive knee flexion.

scholarly journals Newly designed computer controlled knee-ankle-foot orthosis (Intelligent Orthosis)

1998 ◽  
Vol 22 (3) ◽  
pp. 230-239 ◽  
Author(s):  
T. Suga ◽  
O. Kameyama ◽  
R. Ogawa ◽  
M. Matsuura ◽  
H. Oka
Keyword(s):  
Lower Limb ◽  
Stance Phase ◽  
Gait Cycle ◽  
Normal Subjects ◽  
Swing Phase ◽  
Ankle Foot Orthosis ◽  
Normal Gait ◽  
Heel Contact ◽  
Computer Controlled ◽  
Foot Orthosis

The authors have developed a knee-ankle-foot orthosis with a joint unit that controls knee movements using a microcomputer (Intelligent Orthosis). The Intelligent Orthosis was applied to normal subjects and patients, and gait analysis was performed. In the gait cycle, the ratio of the stance phase to the swing phase was less in gait with the knee locked using a knee-ankle-foot orthosis than in gait without an orthosis or gait with the knee controlled by a microcomputer. The ratio of the stance phase to the swing phase between controlled gait and normal gait was similar. For normal subjects the activity of the tibialis anterior was markedly increased from the heel-off phase to the swing phase in locked gait. The muscle activities of the lower limb were lower in controlled force in locked gait showed spikes immediately after heel-contact in the vertical at heel-contact in the sagittal to locked gait, gait with the Intelligent Orthosis is smooth and close to normal gait from the viewpoint of biomechanics. Even in patients with muscle weakness of the quadriceps, control of the knee joint using the Intelligent Orthosis resulted in a more smooth gait with low muscle discharge.

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