Biomechanical Comparison of a New Dynamic Ankle Orthosis to a Standard Ankle-Foot Orthosis During Walking

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Chloe L. Chung ◽  
Denis J. DiAngelo ◽  
Douglas W. Powell ◽  
Max R. Paquette
Keyword(s):  
Angular Velocity ◽  
Cartilage Damage ◽  
Three Dimensional ◽  
Frontal Plane ◽  
Ankle Injuries ◽  
Ankle Motion ◽  
Ankle Foot Orthosis ◽  
Plantar Pressures ◽  
Biomechanical Comparison ◽  
Foot Orthosis

Abstract Patients who sustain irreversible cartilage damage or joint instability from ankle injuries are likely to develop ankle osteoarthritis (OA). A dynamic ankle orthosis (DAO) was recently designed with the intent to offload the foot and ankle using a distractive force, allowing more natural sagittal and frontal plane ankle motion during gait. To evaluate its efficacy, this study compared ankle joint kinematics and plantar pressures among the DAO, standard double upright ankle-foot orthosis (DUAFO), and a nonorthosis control (CON) condition in healthy adults during walking. Ten healthy subjects (26 ± 3.8 yr; 69.6 ± 12.7 kg; and 1.69 ± 0.07 m) walked on a treadmill at 1.4 m/s in three orthosis conditions: CON, DAO, and DUAFO. Ankle kinematics were assessed using a three-dimensional (3D) motion capture system and in-shoe plantar pressures were measured for seven areas of the foot. DAO reduced hallux peak plantar pressures (PPs) compared to CON and DUAFO. PPs under toes 2–5 were smaller in DAO than DUAFO, but greater in DUAFO compared to CON. Early stance peak plantarflexion (PF) angular velocity was smaller in DAO compared to CON and DUAFO. Eversion (EV) ROM was much smaller in DUAFO compared to CON and DAO. Early stance peak eversion angular velocity was smaller in DAO and much smaller in DUAFO compared to CON. This study demonstrates the capacity of the DAO to provide offloading during ambulation without greatly affecting kinematic parameters including frontal plane ankle motion compared to CON. Future work will assess the effectiveness of the DAO in a clinical osteoarthritic population.

scholarly journals Effects of plantar flexion resistive moment generated by an ankle-foot orthosis with an oil damper on the gait of stroke patients: a pilot study

2012 ◽  
Vol 37 (3) ◽  
pp. 212-221 ◽  
Author(s):  
Sumiko Yamamoto ◽  
Naoki Tomokiyo ◽  
Tadashi Yasui ◽  
Toshikazu Kawaguchi
Keyword(s):  
Plantar Flexion ◽  
Reaction Force ◽  
Three Dimensional ◽  
Chronic Phase ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Ankle Foot Orthosis ◽  
Paretic Limb ◽  
Gait Parameters ◽  
Foot Orthosis

Background: An ankle-foot orthosis with an oil damper was previously developed to assist the first rocker function during gait, but the effects of the amount of resistive moment generated on gait have not been clarified. Objectives: To measure the amount of resistive moment generated by the ankle-foot orthosis with an oil damper during gait and determine its effect on the gait of patients with stroke. Study Design: Preliminary cross-sectional study. Methods: The gait of four patients with stroke in the chronic phase was measured in four conditions: without an ankle-foot orthosis and with the ankle-foot orthosis with an oil damper generating three different amounts of resistive moment. Measurements were taken with a three-dimensional motion analysis system and a specially designed device to determine the resistive moment. Results: The resistive moment was observed in the former half in stance of the paretic limb, and its magnitude was less than 10 N m. Some gait parameters related to terminal stance and preswing were affected by the amount of resistive moment. The forward component of floor reaction force and the shank vertical angle showed peak values when the patients reported feeling most comfortable during gait. Conclusion: Although the resistive moment generated by the ankle-foot orthosis with an oil damper was small, it was sufficient to alter gait. Clinical relevance To maximize the effectiveness of ankle-foot orthoses, it is necessary to know the effects of resistive moment on the gait of patients with stroke. The ankle-foot orthosis with an oil damper assists the first rocker function in gait and also affects the gait in a later phase in stance. The peak values of some gait parameters coincided with patients reporting gait to be most comfortable. It is important to know that ankle-foot orthosis with an oil damper assistance in the first rocker alters the weight acceptance on the paretic limb and affects the gait parameters related to propulsion ability in stance.

Portable Pneumatic Power-Harvesting Ankle-Foot-Orthosis

2008 ◽  
Author(s):  
Robin Chin ◽  
Elizabeth T. Hsiao-Wecksler ◽  
Eric Loth ◽  
Andrew Alleyne ◽  
Scott Manwaring ◽  
...  
Keyword(s):  
Power Source ◽  
Power Harvesting ◽  
Ankle Motion ◽  
Ankle Foot Orthosis ◽  
Locking Mechanism ◽  
External Power Source ◽  
Cam Follower ◽  
External Power ◽  
Pneumatic Power ◽  
Foot Orthosis

In this paper, we present a novel ankle-foot-orthosis (AFO) design that controls ankle motion by providing a plantarflexion stop with free dorsiflexion during gait. The biomechanical controls are accomplished with a unique application of a cam-follower design that uses pneumatic power harvested via an air bellow embedded into the insole of the AFO (Figure 1). This portable design is self-contained and does not require any external power source to provide for the plantarflexion stop locking mechanism. It is the first step in a series of untethered fluid-powered orthotic devices.

Reduction in the Knee Adduction Moment During Walking Using Laterally-Wedged Shoes With and Without Ankle Support

2010 ◽  
Author(s):  
Jennifer Erhart ◽  
Thomas Andriacchi
Keyword(s):  
Knee Adduction Moment ◽  
Dynamic Effects ◽  
Medial Compartment Osteoarthritis ◽  
Ankle Motion ◽  
Ankle Foot Orthosis ◽  
Rate Of Progression ◽  
High Maximum ◽  
Ankle Support ◽  
Lateral Wedges ◽  
Foot Orthosis

A high maximum adduction moment at the knee during walking has been associated with an increased rate of progression [1] and worse treatment outcome [2] of medial compartment osteoarthritis (OA) of the knee. Laterally-wedged insoles and shoes have been shown to reduce the knee adduction moment in healthy and osteoarthritic populations [3,4]. However, the mechanism of the effectiveness of such interventions is not well understood. Toda et al. showed that subtalar strapping with laterally wedged insoles in osteoarthritic subjects can improve valgus correction, but the authors did not look at the dynamic effects of walking [5]. A second study looked at the effects of lateral wedges with both semi-rigid ankle support and a rigid ankle-foot-orthosis and found a reduction in the adduction moment only with ankle support and a 10° lateral wedge. The wedge alone did not produce a reduction in the adduction moment [6]. Thus, it seems that the mechanism of action of the lateral wedge may be influenced by ankle motion.

Design of an Automated Device to Measure Sagittal Plane Stiffness of an Articulated Ankle-Foot Orthosis

2010 ◽  
Vol 34 (4) ◽  
pp. 439-448 ◽  
Author(s):  
Toshiki Kobayashi ◽  
Aaron k. L. Leung ◽  
Yasushi Akazawa ◽  
Hisashi Naito ◽  
Masao Tanaka ◽  
...  
Keyword(s):  
Angular Velocity ◽  
Range Of Motion ◽  
Fatigue Testing ◽  
Sagittal Plane ◽  
Testing Machine ◽  
Ankle Foot Orthosis ◽  
Resistive Torque ◽  
Angular Velocities ◽  
Rotary Plate ◽  
Foot Orthosis

The purpose of this study was to design a new automated stiffness measurement device which could perform a simultaneous measurement of both dorsi- and plantarflexion angles and the corresponding resistive torque around the rotational centre of an articulated ankle-foot orthosis (AAFO). This was achieved by controlling angular velocities and range of motion in the sagittal plane. The device consisted of a hydraulic servo fatigue testing machine, a torque meter, a potentiometer, a rotary plate and an upright supporter to enable an AAFO to be attached to the device via a surrogate shank. The accuracy of the device in reproducing the range of motion and angular velocity was within 4% and 1% respectively in the range of motion of 30&dG (15&dG plantarflexion to 15&dG dorsiflexion) at the angular velocity of 10&dG /s, while that in the measurement of AAFO torque was within 8% at the 0&dG position. The device should prove useful to assist an orthotist or a manufacturer to quantify the stiffness of an AAFO and inform its clinical use.

Ankle–foot orthosis design between the tradition and the computerized perspectives

2019 ◽  
Vol 43 (5) ◽  
pp. 354-361
Author(s):  
Ayham Darwich ◽  
Hasan Nazha ◽  
Aleen Sliman ◽  
William Abbas
Keyword(s):  
Numerical Models ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Material Loss ◽  
Ankle Foot Orthosis ◽  
Engineering Software ◽  
Numerical Design ◽  
Dynamic Loading Conditions ◽  
Design And Testing ◽  
Foot Orthosis

This study focuses on the drop foot case related to hyperthyroidism of the ankle joint resulting in the relaxation of the toes during walking. This condition requires treatment using an ankle–foot orthosis. Traditional orthosis techniques lack precision and depend on the skill of the fabricator. This research aims to make a bias in ankle–foot orthosis design and analysis methods, where a complete methodology of numerical design and testing has been proposed using advanced engineering software. A numerical model of the patient’s foot was generated and used to design an ankle–foot orthosis model using SolidWorks. The designed model was mechanically analyzed by the finite element method using ANSYS Workbench 16.1 under different static and dynamic loading conditions. The ankle–foot orthosis model was numerically designed and analyzed before the manufacturing process. This is believed to reduce time and material loss and foster the use of numerical models in biomedical applications. This study suggests focusing on the design and analysis of orthoses according to the patient’s measurements. This is expected to increase the comfort and raise the level of treatment. Numerical design methods also enable precise manufacturing using computerized devices such as three-dimensional printers.

Biomechanical Comparison of Dominant and Non-Dominant Limbs During Leap-Landings in Contemporary Style Female Dancers

2021 ◽  
Author(s):  
Luke Chowning ◽  
John Krzyszkowski ◽  
Brandon Nunley ◽  
Ryan Lanier ◽  
Isabella Gonzales ◽  
...  
Keyword(s):  
Sagittal Plane ◽  
Reaction Force ◽  
Three Dimensional ◽  
Frontal Plane ◽  
Effect Sizes ◽  
Vertical Ground Reaction Force ◽  
Paired Samples ◽  
Execution Strategy ◽  
Biomechanical Comparison ◽  
Angular Impulse

The execution strategy of technical dance movements is constrained by aesthetic and qualitative artistic requirements. As such, there are limited leap-landing strategies that may be used by dancers when executing a grand jeté or saut de chat. The purpose of this study was to determine potential differences in lower extremity angular positioning and joint loading when performing a dance-style leap landing. Fifteen female dancers (age: 20 ± 1 years; height: 1.61 ± 0.13 m; weight: 58.00 ± 11.89 kg) completed six leap-landing trials during which three-dimensional kinematics and kinetics data were collected. Paired-samples t-tests (α = 0.05) and Cohen’s d effect sizes (ES; large ≥ 0.8) were used to compare the following variables: jump height; peak vertical ground reaction force; loading time; loading rate; joint angular positioning of the ankle, knee, hip, and trunk in the frontal and sagittal planes; and joint angular impulse of the ankle, knee, and hip in the frontal and sagittal planes between the dominant and non-dominant limbs. Frontal plane hip angular impulse was significantly greater in the dominant limb (p = 0.023, ES = 1.53). While no other statistically significant differences were observed between dominant and non-dominant limbs, moderate effect sizes were observed for the hip and trunk angles in the frontal plane along with hip impulse in the sagittal plane. This study indicates that dancers might slightly alter their landing strategy at the hip joint when leap-landing onto the dominant limb. Frontal plane hip mechanics should be considered to minimize overuse injury potential in the dominant limb.

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