The development of a 3D-printed relative motion orthosis and field testing of 3D and thermoplastic tape relative motion orthoses.

Abstract

Background: Three-dimensional (3D) printing offers an alternative for orthotic fabrication, particularly where thermoplastics are costly or not readily available. This report explored a universal-design 3D-printed relative motion orthosis and compared short-term user satisfaction with custom thermoplastic tape (Orficast) relative motion flexion orthoses.

Purpose: To design and produce universal 3D-printed relative motion orthosis using iterative prototyping and compare it with custom thermoplastic tape relative motion flexion orthoses.

Study design: Comparative field test with iterative prototype development.

Methods: The study had two phases. In phase 1, a universal-design 3D relative motion orthosis was developed using repeated design-print-fit-refine cycles with feedback from an expert focus group. In phase 2, patients with Burton stage I boutonnière deformity were randomly assigned to wear either a 3D-printed relative motion flexion orthosis or a custom thermoplastic tape relative motion flexion orthosis for 1 week. User satisfaction was evaluated using the Turkish version of the Orthotics Prosthetics Users Survey (OPUS) satisfaction module.

Results: Four prototypes and two final designs were produced; the final design met the focus-group checklist criteria. Forty participants were randomized (20 per group); nonadherence by four 3D group participants resulted in exclusion, leaving 16 (3D printed orthoses) and 20 (thermoplastic orthoses) for analysis (n = 36). OPUS Satisfaction scores did not differ significantly between groups after 1 week (3D printed orthoses: 93.19 ± 6.28 vs thermoplastic orthoses: 89.35 ± 11.17; p = 0.24). The material cost was €2.75 (US$3.19) for the 3D-printed orthosis vs €7.50 (US$8.70) for the thermoplastic tape orthosis in our setting.

Conclusions: In this study 3D printing lowered material costs and reduced therapist time compared to custom thermoplastic tape relative motion flexion orthoses. Patients with stage 1 Burton boutonniere deformity wearing the 3D-printed or custom thermoplastic tape relative motion flexion orthoses reported comparable satisfaction after 1-week wear time.