The effect of three dimensional printing hinged ankle foot orthosis for equinovarus control in stroke patients

Abstract

Background: Hemiplegic stroke patients often suffered from equinovarus foot which result in plantar pressure overload over lateral sole. 3D printing is a promising technique utilized in orthosis fabrication, and the effects on plantar pressure remains unclear. The aim in this study focus on the effect of 3D printed ankle foot orthosis, by measuring plantar parameters.

Methods: Ten patients with first-ever unilateral stroke were enrolled in this study. All patients performed 10-m walk test in 3 conditions, including ambulation with 3D printed hinged ankle foot orthosis, anterior ankle foot orthosis, and bare foot. The plantar contact area, maximum force, and peak pressure were collected and evaluate using Pedar X in-sole system. Plantar parameters symmetric analysis was conducted to assess the similarity between hemiplegic leg and unaffected leg. We used Quebec User Evaluation of Satisfaction with Assistive Technology questionnaire to survey patients' subjective satisfaction.

Findings: Walking with 3D printed ankle foot orthosis revealed significant increase in medial midfoot peak pressure compared to bare foot walking. Plantar parameters symmetric analysis illustrated more even medial midfoot contact area compared to bare foot walking. In satisfaction survey, walking with 3D printed ankle foot orthosis outweighs anterior ankle foot orthosis in fitting and durableness.

Interpretation: Dynamic plantar pressure measurement is useful for evaluation of equinovarus deformity in hemiplegic stroke patients. Wearing 3D printed ankle foot orthosis increase plantar pressure in medial midfoot area. And medial midfoot contact area is also more symmetry.

Keywords: 3D printing; Ankle foot orthosis; Plantar pressure; Stroke.