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3D Printed Hand Splints
A B C

Figure 2. Traditional thermoplastic metacarpal brace for a metacarpal fracture. (A) Palmar view. (B) Dorsal view. (C) Material of the
custom-made splint.

as similar as possible to that for traditional splints made A B
of thermoplastic material, without the addition of local
reinforcements or further meshes, to achieve a reliable
comparison of the two devices. The virtual computer-aided
design process comprised smoothing of surfaces, filling
in holes in the acquired 3D mesh, and defining an offset
of 1 mm over the skin for comfort. Bony prominences
were respected by manually increasing local offset. The
material thickness was set to 3 mm, which is comparable Figure 3. 3D design of a metacarpophalangeal joint immobilizing
to that of thermoplastic material. The splints were printed splint for an ulnar collateral ligament tear. (A) Virtual computer-
in our in-house 3D print laboratory (3dprintlab@usb.ch) aided design. (B) In-house 3D print laboratory.
from PLA on a MakerBot Replicator+ (Figure 3). We Table 1. 3D splint properties
chose to use fused deposition modeling (FDM) because
of its low price and widespread availability. PLA is Surface scanner Vectra M5 Scanner (Canfield
a bio-based, biocompatible, biodegradable, and non- Scientific Inc., Parsippany, NJ,
toxic polymer, already widely used for orthopedic and USA)
dental applications and approved by authorities for 3D design software 3-matic® (Materialise, Leuven,
[18]
medical use on skin. After printing, each splint was post- Belgium)
processed manually by removal of support structures 3D printer MakerBot Replicator+ (MakerBot
from the printing process and smoothing of the entire Industries, Brooklyn, NY, USA)
splint surface. Table 1 summarizes the splint production Printing material Polylactic acid
properties. During the first occupational therapy session, Printing technique Fused deposition modeling
straps were added and, in the case of an unsatisfying fit, Printing pattern Linear
the 3D splint was directly adjusted to the patient’s hand Layer thickness 0.2 mm
by the occupational therapist using wet and/or dry heat to Post-processing Manual
deform the splint (Figure 4). Favorable Rigid, lightweight, with limited
2.3. Data acquisition and statistical analysis mechanical thermoplasticity (adjustability),
properties of printed biodegradable
To assess comfort and satisfaction, we asked patients splints
to complete questionnaires concerning their wearing
experience, general problems while wearing the splint, which they were asked to rate their satisfaction with the
and satisfaction with different aspects of the splint. The splint for both groups, to record adjustments made, and to
questionnaires were specifically designed for this study, collect data on the incidence and nature of complications.
as no validated tools were available (Appendix). Production times for both splint types were documented.
In addition to these questionnaires, the treating Data analysis was mainly qualitative because of the
occupational therapists completed an assessment in planned small number of participants in this feasibility

130 International Journal of Bioprinting (2022)–Volume 8, Issue 1