Uncovering Challenges and Opportunities for 3D Printing Assistive Technology with Physical Therapists
Samantha McDonald, Niara Comrie, Erin Buehler, Nicholas Carter, Braxton Dubin, Karen Gordes, Sandy McCombe-Waller, Amy Hurst · 2016 · Proceedings of the 18th International ACM SIGACCESS Conference on Computers and Accessibility (ASSETS '16) · doi:10.1145/2982142.2982162
Summary
This paper investigates the feasibility and challenges of integrating 3D printing into physical therapy (PT) practice for creating customized assistive technology (AT). Physical therapists routinely modify standardized AT devices using temporary materials like Velcro, tape, and foam, but these solutions may not withstand long-term use. Meanwhile, 35% of purchased AT is abandoned due to poor fit or inadequate customization. The researchers collaborated with PT professors and students at the University of Maryland School of Medicine through three activities: an online survey with four experienced PTs/professors about liability, prototyping practices, and 3D printing perceptions; six months of collaborative design sessions with two PT professors producing 3D printed AT augmentations (custom crutch grips designed via play-dough molds and 3D scanning, and replacement crutch tips tested in PLA, ABS, NinjaFlex, and SemiFlex materials); and a three-session educational unit integrated into a graduate-level PT course for 65 first-year students. Students had virtually no prior experience — 98.3% had never created AT, 100% had never used a 3D printer, and 95% had never used 3D modeling software. Across three classes, students received introductory lectures, hands-on 3D modeling tutorials using Tinkercad, and designed AT augmentations for five simulated patient scenarios involving walking aids (canes, crutches, walkers, hemiwalkers).
Key findings
All five student groups successfully created AT models for their patient scenarios, with four groups designing grip augmentations for existing devices and one group designing custom crutch tips. Students overwhelmingly preferred 3D scanning and play-dough modeling (73.6%) over digital 3D modeling software, finding Tinkercad's interface unintuitive despite its novice-friendly reputation. Students reported clear increases in 3D printing knowledge between classes, and belief that 3D printing was a rapidly growing PT field topic rose from 53.3% to 92% after just the first session. However, satisfaction with 3D prints was only 49% — models were often non-functional, wrong scale, improperly scanned, or printed in the wrong material. Four key considerations emerged: (1) PTs strongly preferred augmenting existing standardized AT (75%) over creating novel devices, driven by lower cost, reduced liability risk, and reliance on established standards; (2) 3D modeling software needs significant improvements for clinical users, with potential for automated integration of standard AT dimensions; (3) prototype fidelity is critical for clinicians — unlike architects who routinely use miniature models, PTs cannot evaluate a grip that isn't full-scale for the patient's hand; and (4) material selection matters enormously for AT comfort, with standard PLA too rigid for direct body contact and flexible filaments like NinjaFlex needed but unregulated for medical use. Liability was a significant concern: creating custom AT makes the PT the "manufacturer," potentially increasing their liability exposure.
Relevance
This research addresses a practical gap between the promise of 3D printed AT and its actual clinical adoption. For accessibility practitioners and AT developers, the finding that clinicians prefer augmenting existing devices over creating novel ones is strategically important — the most impactful near-term application of 3D printing in AT may be customized add-ons to standardized equipment rather than entirely new devices. The liability concern is a significant barrier that technology solutions alone cannot address: clinicians operating under professional standards face genuine legal risk when prescribing unregulated, self-manufactured devices. The prototype fidelity finding has direct implications for 3D printing education and rapid prototyping — clinical users need full-scale, correct-material prototypes to evaluate fit and function, unlike other design fields where low-fidelity models suffice. The study also demonstrates that three class sessions are insufficient for developing competence in 3D modeling, suggesting that integrating 3D printing into clinical practice requires longer-term educational investment or simplified tools that bypass complex modeling software entirely.
Tags: 3D printing · assistive technology · DIY assistive technology · physical disability · digital fabrication · education · rehabilitation · co-design