Page 528 - IJB-10-2

International Journal of Bioprinting 3D printing of custom mallet splints

matched and patient-specific devices with high tunability, 71,315 attendances at their ED and IUs in 2019. To that
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and can provide an innovative approach to individualized end, the inclusion of three units provided a representative
healthcare, thus expanding the manufacturing of custom group for study recruitment. The time frame for
devices within the healthcare settings. 18 recruitment for the study was 6 months, commencing in
Previous studies have assessed the feasibility of treating January 2023 and ending in June 2023.
mallet fingers with 3D printing technology. Among these The inclusion criteria were adult patients presenting
studies, five tested 3D-printed devices on non-injured to the ED or IU with a Type 1 or Type 2 closed mallet
volunteers. 19-23 Wong et al. assessed the feasibility of 3D finger injury based on the Doyle Classification System.

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printing a customized mallet splint on site for 13 non- The exclusion criteria were injuries with obvious
injured Mars Desert Research Station mission crew abnormal anatomy or skin complications. There was no
members. Choi et al. compared custom casts comprising randomization of participants. All patients that met the
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plaster of Paris, evaluated their use against a 3D-printed inclusion criteria were invited to participate in the study by
splint, and conducted a wearability assessment in an their treating HCP.
unreported number of non-injured participants.
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Zolfagharian et al. designed and 3D-printed a custom 2.3. Design and production of 3D-printed splints
mallet splint for one healthy volunteer. Papavasiliou et Measurements at eight discrete points of the injured finger
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al. compared custom 3D-printed splints to conventional were recorded (Figure 1) using a vernier calipers (Mitutoyo
custom-made thermoplastic splints and assessed patient brand) with a resolution of 0.01 mm.
comfort and satisfaction for hand injuries. Gupta et al.
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assessed a 3D-printed mallet splint on 20 non-injured Calipers were the chosen measuring device because
volunteers. Nam et al. aimed to treat an injured patient they were available to the research team at the beginning of
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with a mallet injury using a 3D-printed device. These six the study. They were also more practical because they did
studies did not assess bespoke 3D-printed mallet splints in not require specialist equipment (3D scanner, dedicated
the treatment of mallet injury for multiple patients. Also, computer) or specialist training on a new technology.
none assessed patient and healthcare professional (HCP) A 3D CAD model of the custom splint was designed
acceptance of the 3D-printed mallet splint. in SolidWorks® (Dassault Systems, France) using the
The primary aim of this study is to evaluate the clinical dimensions recorded from the patient. A design table was
benefit of applying a custom 3D-printed mallet splint to used to automatically modify a standard base model using
multiple patients requiring splinting for mallet injury. The the unique dimensions of the patient, creating a bespoke
secondary aim is to explore patient and HCP acceptance splint for every patient with no additional design effort or
of 3D-printed mallet splints, in relation to fit, comfort, engineering required (Figure 2).
and appropriateness. The customization of the 3D-printed
splint, where the anthropometrics of each patient guided 2.4. Study process
the design, was key to providing comfort while providing 2.4.1. Initial presentation
clinical benefit. This is the first prospective, multi-site At their initial presentation (t = 0 days), patients who met
study offering custom 3D-printed devices to a cohort of the inclusion criteria and consented to participate in the
patients (n = 10) for treating mallet finger injury.
study were allocated four follow-up appointments (t = 7,
2. Materials and methods t = 9, t = 21, and t = 56 days; Table 1).
The patients were fitted with a generic Stack splint
This study was approved by the Research Ethics Committee
of ULHG (reference 087/2022). Written informed consent at their initial presentation and were instructed to wear
was obtained from all participants before beginning the study. this temporarily until the 3D-printed splint was ready
approximately 7 days later. This was to ensure immediate
2.1. Materials commencement of a treatment and to allow for any
The bespoke splints were printed on a Figure 4 (3D printer swelling to reduce before being measured and fitted for
make) standalone 3D Printer (3D Systems, South Carolina, the 3D-printed splint. The Stack splint was, therefore,
United States of America) using the PRO-BLK material worn during the period when the patient’s finger was most
from the same manufacturer. swollen. The logistics of the study did not allow deviation
from this.
2.2. Study design
This was a multi-site study conducted in three hospitals Each patient was given discharge advice consistent with
across ULHG. This hospital group saw approximately the normal standard of care in each unit. The discharge

Volume 10 Issue 2 (2024) 520 doi: 10.36922/ijb.1963