Orthotists' perspectives on the adjustment of 3D printed ankle foot orthoses: A mixed methods feasibility study

BACKGROUND: An important part of the orthotic treatment process includes performing adjustments to the shape or design of the orthosis to improve its fit and function. However, the ability to adjust 3D printed (3DP) materials is not well understood. OBJECTIVES: (1) To evaluate the usability of completing adjustments on 3DP ankle foot orthoses (AFOs) vs. traditionally-fabricated AFOs, and (2) to explore orthotists' perspectives on the advantages, disadvantages, and similarities of adjusting 3DP materials and identify potential solutions for disadvantages. STUDY DESIGN: Mixed-methods cross-sectional study. METHODS: Ten participating certified orthotists performed a sequence of predetermined adjustment tasks on 3DP AFOs. The Single Ease Question and the System Usability Scale (SUS) were compared between traditional vs. 3DP AFO adjustments. Semistructured interviews were conducted, and a thematic analysis identified key themes. RESULTS: Single Ease Question scores were significantly lower for 3DP adjustments in 50% of tasks. The mean SUS total score was significantly lower ( p < 0.001) for tasks completed on 3DP AFOs compared with traditional AFOs. The thematic analysis identified challenges related to aesthetics, heating, grinding, brittleness, and timing of adjustments. Several similarities and some minor benefits were also noted. Despite challenges, orthotists demonstrated optimism about the 3DP material and proposed several solutions for improvement including optimizing techniques and introducing postprocessing. CONCLUSIONS: 3D printed orthoses were more difficult to adjust and had lower usability for adjustment compared with traditional ones. However, orthotists felt that they would be able to use the material in clinical practice if some of the proposed solutions were implemented.