A quantitative analysis of optimum design for rigid ankle foot orthoses: The effect of thickness and reinforcement design on stiffness.

Autor:	Chatzistergos PE; Centre for Biomechanics and Rehabilitation Technologies, Staffordshire University, Stoke-on-Trent, UK., Eddison N; Centre for Biomechanics and Rehabilitation Technologies, Staffordshire University, Stoke-on-Trent, UK.; The Royal Wolverhampton NHS Trust, New Cross Hospital, Wolverhampton, UK., Ganniari-Papageorgiou E; Warwick Manufacturing Group, University of Warwick, Coventry, UK., Chockalingam N; Centre for Biomechanics and Rehabilitation Technologies, Staffordshire University, Stoke-on-Trent, UK.
Jazyk:	angličtina
Zdroj:	Prosthetics and orthotics international [Prosthet Orthot Int] 2024 Apr 01; Vol. 48 (2), pp. 204-212. Date of Electronic Publication: 2023 Jun 13.
DOI:	10.1097/PXR.0000000000000247
Abstrakt:	Background: An ankle foot orthosis (AFO) which is prescribed to be rigid should only deform a small amount to achieve its clinical goals. Material thickness and the design of reinforcing features can significantly affect AFO rigidity, but their selection remains based on anecdotal evidence. Objectives: To quantify the effect of these parameters on AFO stiffness and to set the basis for quantitative guidelines for the design optimisation of rigid AFOs. Study Design: Experimental and computational study. Methods: A polypropylene AFO was produced according to UK standard practice and its stiffness was experimentally measured for 30Nm of dorsiflexion. Its geometry and mechanical characteristics were utilised to create a finite element (FE) model of a typical AFO prescribed to be rigid. Following validation, the model was used to quantify the effect of material thickness and reinforcement design (i.e., reinforcement placement, length) on stiffness. A final set of AFO samples was produced to experimentally confirm key findings. Results and Conclusions: For a specific AFO geometry and loading magnitude, there is a thickness threshold below which the AFO cannot effectively resist flexion and buckles. FE modelling showed that stiffness is maximised when reinforcements are placed at the anterior-most position possible. This key finding was also experimentally confirmed. The stiffness of an AFO reinforced according to standard practice with lateral and medial ribbing was 4.4 ± 0.1 Nm/degree. Instructing the orthotic technician to move the ribbings anteriorly increased stiffness by 22%. Further stiffening is achieved by ensuring the reinforcements extend from the footplate to at least two-thirds of the AFO's total height. (Copyright © 2023 International Society for Prosthetics and Orthotics.)
Databáze:	MEDLINE
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