scholarly journals Novel Plantar Surface Design of a Hinged Ankle Foot Orthosis (HAFO) Manufactured by 3D Printing

Author(s):  
Mariana Ribeiro Volpini Lana1 ◽  
Paulo Henrique Rodrigues Guilherme Reis ◽  
Anderson Horta ◽  
Joana Pimenta Maia ◽  
Mariana Rodrigues Carvalho de Aquino ◽  
...  
2020 ◽  
Vol 41 (Supplement_1) ◽  
pp. S256-S257
Author(s):  
Lisa LePage

Abstract Introduction Distal lower extremity STSG’s present a challenge with the balance of early mobility and immobilization of the ankle. Traditional commercially available ambulation boots or pre-fabricated orthotics may impose circumferential compression endangering graft integrity. Custom fabricated posterior AFO’s comprised of thermoplastic, scotch cast or fiberglass materials are not recommended for weight-bearing of the lower extremity during mobility/ambulation. What may also hinder promotion of early mobility is having a multitude of injuries or advanced age with decreased ability to adhere to a LE NWB status. An anterior approach to immobilization of the ankle was thought of to free the plantar surface of the foot for weight-bearing. The open concept of the orthosis itself minimizes direct contact with the involved LE graft. This promotes graft integrity during mobility with ankle immobilization. Methods Materials: Thermoplastic material, scissors, strapping, dense adhesive foam, adhesive Velcro and a heat gun. Fabrication: Measure the point of distance between where the desired proximal end of the orthosis would be to the patient’s metatarsal heads on the dorsal aspect of the foot; double it to calculate the amount of material needed. The width of the material should be approx. 3 to 4 inches. Warm material and tri-fold it together reducing width to approx. 1 ½ to 2 inches to increase stability. Shape the folded material into a continuous oval and place on the patient’s distal LE. As the material cools, shape the oval away from the medial/ lateral aspects of the distal LE restricting the points of contact to the anterior most proximal and distal aspect of the desired splint parameters. Remove once cooled and add dense adhesive foam to the 2 points of contact that will rest against the patient. This will allow for a slight area of “give” against the patient during weight-bearing of the LE/foot. Velcro and straps are added to the proximal/distal ends of the oval; heating the adhesive side will imbed the Velcro allowing increased durability with repeated donning/doffing. Results The open construction of this orthosis allows different degrees of weight-bearing eliminating contact with the distal LE STSG. The forefoot and heel are available to weight bear safely within the confines of the open anterior ankle foot orthosis. Conclusions Patients have been trialed with/without an AD with success in the achievement of ankle immobilization with mobility. Weight-bearing instructions that accompany this splint wear is foot placement rather than a normal heel strike cadence to avoid undue pressure at the proximal aspect of the splint on the lower extremity. Applicability of Research to Practice This splint has been successfully utilized for immobilization without compromise to STSG integrity due to the anterior open support it offers the ankle. Perhaps this concept could be applied to other joints to avoid direct contact of the splint with STSG during the initial stages of healing.


2020 ◽  
Vol 26 (10) ◽  
pp. 1677-1685 ◽  
Author(s):  
Harish Kumar Banga ◽  
Parveen Kalra ◽  
Rajendra M. Belokar ◽  
Rajesh Kumar

Purpose The purpose of this study is improvement of human gait by customized design of ankle foot orthosis (AFO). An has been the most frequently used orthosis in children with cerebral palsy. AFOs are designed to boost existing features or to avoid depression or traumatize muscle contractures. The advantages of AFO’s utilized for advancement in human walk attributes for the improvement in foot deformities patients or youngsters with spastic loss of motion. In this research on the customized design of AFO's to improve gait, there are limitations during walking of foot drop patients. In children with foot drops, specific AFOs were explicitly altered to improve parity and strength which are beneficial to walking positions. Design/methodology/approach This study proposes the customized design of AFOs using computerized and additive manufacturing for producing advances to alter the design and increase comfort for foot drop patients. Structuring the proposed design fabricated by using additive manufacturing and restricted material, the investigation was finalized at the Design Analysis Software (ANSYS). The system that performs best under investigation can additionally be printed using additive manufacturing. Findings The results show that the customized design of AFOs meets the patient’s requirements and could also be an alternative solution to the existing AFO design. The biomechanical consequences and mechanical properties of additive manufactured AFOs have been comparable to historically synthetic AFOs. While developing the novel AFO designs, the use of 3D printing has many benefits, including stiffness and weight optimization, to improve biomechanical function and comfort. To defeat the issues of foot drop patients, a customized AFO is used to improve the human gait cycle with new material and having better mechanical properties. Originality/value This research work focuses on the biomechanical impacts and mechanical properties of customized 3D-printed AFOs and compares them to traditionally made AFOs. Customized AFO design using 3D printing has numerous potential advantages, including new material with lightweight advancement, to improve biomechanical function and comfort. Normally, new applications mean an incremental collection of learning approximately the behavior of such gadgets and blending the new design, composite speculation and delivered substance production. The test results aim to overcome the new AFO structure issues and display the limited components and stress examination. The outcome of the research is the improved gait cycle of foot drop patients.


2010 ◽  
Vol 4 (2) ◽  
Author(s):  
Ricky Mehta ◽  
Eric L. Rohrs ◽  
Katarina F. Lipat ◽  
Evan C. Reed ◽  
Manish Paliwal

To design a smart ankle-foot orthosis (SAFO) that improves upon current ankle-foot orthoses used to treat steppage gait. Current ankle-foot orthoses are subjected to significant stresses on the ankle region of the structure, causing discomfort and the possible failure of the AFO. Although these AFOs have a constant stiffness, they do not reduce the occurrence of slap foot, where the foot slaps on the ground rather than gradually lowering it. The SAFO is an active ankle-foot orthosis that allows the user’s foot to follow a normal gait cycle. It is designed to reduce stress at the ankle by allowing for movement of the foot beyond a 90 deg angle for plantarflexion. The hinged ankle-foot orthosis is incorporated with a novel dual hydraulic-cylinder system, two tension springs, and force sensitive resistors. The force sensors are placed at the hallux, first metatarsal head, fifth metatarsal base, and heel. The foot movement actuation follows the force applied to the plantar surface of the foot during gait. The sensor outputs are fed to a signal processor and control interface to coordinate the motor actuation with the forces exerted by the user. The motor turns the screw attached to the hydraulic cylinders, which, thereby, control the orifice size by moving a plate in the cylinder, thus, changing the resistance. The cylinder filled with air will be pressurized during the lean phase, as the orifices will be closed and will provide power just as a spring would during the heel-off phase. After the heel strike, the resistance of the fluid-filled cylinder is decreased to slowly lower the foot. Once the foot is flat, the resistance of the fluid-filled cylinder is increased to keep the foot in a position to allow for toe clearance. During the heel-off event, the air-filled cylinder will assist the user with the power to push off. When toe-off occurs, the fluid-filled cylinder will decrease the resistance to allow the tension springs to bring the foot back to neutral position. To power the motor and sensors, a rechargeable battery pack is placed in a waist bag. The SAFO’s flexible design uses a novel combination of hydraulic-pneumatic cylinders to prevent foot drop, and restore the user’s sense of normalcy by providing late stance plantarflexion and a return to neutral position in early swing phase.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yoo Jin Choo ◽  
Min Cheol Chang

AbstractWe conducted a meta-analysis to investigate the effectiveness of ankle–foot orthosis (AFO) use in improving gait biomechanical parameters such as walking speed, mobility, and kinematics in patients with stroke with gait disturbance. We searched the MEDLINE (Medical Literature Analysis and Retrieval System Online), CINAHL (Cumulative Index to Nursing and Allied Health Literature), Cochrane, Embase, and Scopus databases and retrieved studies published until June 2021. Experimental and prospective studies were included that evaluated biomechanics or kinematic parameters with or without AFO in patients with stroke. We analyzed gait biomechanical parameters, including walking speed, mobility, balance, and kinematic variables, in studies involving patients with and without AFO use. The criteria of the Cochrane Handbook for Systematic Reviews of Interventions were used to evaluate the methodological quality of the studies, and the level of evidence was evaluated using the Research Pyramid model. Funnel plot analysis and Egger’s test were performed to confirm publication bias. A total of 19 studies including 434 participants that reported on the immediate or short-term effectiveness of AFO use were included in the analysis. Significant improvements in walking speed (standardized mean difference [SMD], 0.50; 95% CI 0.34–0.66; P < 0.00001; I2, 0%), cadence (SMD, 0.42; 95% CI 0.22–0.62; P < 0.0001; I2, 0%), step length (SMD, 0.41; 95% CI 0.18–0.63; P = 0.0003; I2, 2%), stride length (SMD, 0.43; 95% CI 0.15–0.71; P = 0.003; I2, 7%), Timed up-and-go test (SMD, − 0.30; 95% CI − 0.54 to − 0.07; P = 0.01; I2, 0%), functional ambulation category (FAC) score (SMD, 1.61; 95% CI 1.19–2.02; P < 0.00001; I2, 0%), ankle sagittal plane angle at initial contact (SMD, 0.66; 95% CI 0.34–0.98; P < 0.0001; I2, 0%), and knee sagittal plane angle at toe-off (SMD, 0.39; 95% CI 0.04–0.73; P = 0.03; I2, 46%) were observed when the patients wore AFOs. Stride time, body sway, and hip sagittal plane angle at toe-off were not significantly improved (p = 0.74, p = 0.07, p = 0.07, respectively). Among these results, the FAC score showed the most significant improvement, and stride time showed the lowest improvement. AFO improves walking speed, cadence, step length, and stride length, particularly in patients with stroke. AFO is considered beneficial in enhancing gait stability and ambulatory ability.


2012 ◽  
Vol 45 (15) ◽  
pp. 2658-2661 ◽  
Author(s):  
Marcelo Andrés Gatti ◽  
Orestes Freixes ◽  
Sergio Anibal Fernández ◽  
Maria Elisa Rivas ◽  
Marcos Crespo ◽  
...  

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