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Ankle Foot Orthosis Device

Summary

Patients with neurological conditions such as stroke or cerebral palsy or any orthopaedic injury may develop foot drop as a result of weakness of the anterior lower leg muscles with or without the over-activity of calf muscles. This can result in an abnormal walking pattern where the patient makes initial contact with the ground using his or her forefoot or toes, instead of the heel during each step. We call this toe-walking. Additionally, being biomechanically inefficient, this walking pattern can lead to tripping or falls. This invention is a compact ankle foot orthosis (AFO) for daily use by cerebral palsy and stroke patients. The device which is designed to fit in the shoes will enhance the coordination of the foot muscles and assist patients in the heel-down and toe-off position.

Technology Benefits

Current devices to prevent toe-walking consist of the rigid ankle-foot orthosis, which provided support to the ankle but often could not prevent toeing in the orthosis and shoe, more importantly, did not provide the correct walking pattern for the patient. The invention with biofeedback is able to provide enough resistance to the calf muscles to bring the ankle into the neutral position and allow dorsiflexion or lifting of the foot during the swing phase of walking.The new AFO device is an innovative device that provides an active dorsiflexion force that enables the patient to overcome the foot drop by lifting the forefoot so that the leg can clear the ground and a heel strike can be obtained. Its mechanism is different from most current prefabricated posterior leaf AFO devices which are hinged or rigid and do not provide a dorsiflexion force. These conventional AFO devices provide a passive support to the foot during foot clearance.This new AFO device does not restrict ankle movements but provides functional and dynamic stability for a more normal walking pattern largely attributed to the active spring-loaded force that lifts the foot during swing phase to get ground clearance and heel strike at ground contact.

Technology Application

Cerebral palsy and stroke patients are severely handicapped and lose their independence because of inability to control and co-ordinate muscle contraction due to spasticity. The design is based on the principle that the anterior lower limb muscle is not strong enough to overcome the spasticity calf muscles, hence resulting in a toe-walking pattern. Toe-walking pattern is unstable, tiring and looks abnormal. Uncorrected joint problems and pain eventually make walking impossible for these patients. This device aims to improve the walking pattern, provide better posture, and make walking safer and more efficient for the patient. This will be a huge improvement in improving the quality of life as the patient grows older.

Detailed Technology Description

This new AFO device utilizes an innovative mechanism of foot clearance that is unseen of in the design of existing AFOs that are sold in rehabilitation facilities. It consists of a spring that is loaded when weight is applied during the stance phase of the gait pattern. The tension of the spring can be adjusted according to how much dorsiflexion assistance is required to clear the ground by the wearer. In this way, the wearer can also attempt to utilize his or her own muscle activity to lift his or her foot, Current prefabricated AFOs are rigid and fixed in design, and did not have a movable ankle joint that mimics ankle joint movements.

Application Date

03-Feb-2016

ID No.

TO22001

Country/Region

Singapore