Materials and Manufacturing for Ankle-Foot Orthoses: A Review

Ankle-foot orthoses (AFOs) assist patients with gait impairment by correcting ankle and foot deformities, restoring mobility, reducing pain, and providing protection and immobilization. AFOs can effectively manage various types of gait pathologies, including foot drop, crouch gait, equinus gait, and stiff knee gait. AFOs are available in prefabricated or custom-made forms in various designs. The selection criteria for the fabrication of an AFO are the duration of usage, the amount of applied force, the degree of axial loading, the patient's skin condition, and the cost. The accessibility of diverse materials in the last century has significantly improved orthoses. Ideal orthotic materials must be light, stiff, and strong, and can be made of plastics, metals, polymer-based composites, leather, or a hybrid of different materials. A deeper understanding of the materials employed in the fabrication of AFOs holds the potential for more advanced and efficient orthoses, which can improve patients' ability to ambulate in the real world. The present review provides insight into the various materials utilized for the fabrication of AFOs and describes the benefits and challenges associated with the materials. An attempt has also been made to highlight typical gait pathologies and design concepts in response to them.