Page 534 - IJB-10-2

International Journal of Bioprinting 3D printing of custom mallet splints

Some patients commented that on hot days, or when they do not require specialized computer equipment,
busy using their hands, their injured finger could swell which would have been impractical in this clinical setting
at times. In relation to the generic Stack splint, they said at least. Patients were recruited from three different
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“as this didn’t fit well, I had space to swell.” Conversely, hospital sites, and this would have necessitated three
in relation to the custom-fit 3D-printed splint, they said scanning devices and associated computing requirements.
“there was less space to swell so it could feel tight at times.” 3D scanning could certainly have a role in bespoke splint
Part of the recovery for mallet injury involves flexing design, and further studies should consider this.
the PIPj. Allowing and encouraging flexion of the PIPj 4.2. Patient requirements
reduces difficulty with range of movement and recovery Mallet injuries require patients to be highly involved
when the splint is removed. It also improves functional and dedicated to their recovery. A splint immobilizes the
use of the hand during the DIPj immobilization period. area to promote healing; however, patients must follow
Patients commented that they felt a much better range of
movement with the 3D-printed splint than the Stack splint. strict discharge guidelines, adhere to hand hygiene, and
Patients also commented that they “couldn’t bend the finger complete the treatment time. In this study, every patient
at all” with the generic Stack splint because “it was too had experience of both a generic Stack splint and the
long” and covered the joint. 3D-printed splint within the same treatment period.
Therefore, the ratings of both splints are not just accurate,
4. Discussion and they are immediate when the generic Stack is changed
to the 3D-printed splint. The 3D-printed splint was applied
This research uncovers a clinical benefit, albeit in a small approximately 7 days after the initial injury. Because the
cohort. This was a pilot study involving ten patients. Future injured finger typically swells during the first 7 days post-
studies assessing statistical aspects should consider the injury, it could be argued that the 3D-printed splint was
power of such study to ascertain the number of patients. applied at a less swollen and painful time in the patient’s
Patients successfully recovered using the 3D-printed splint recovery. However, the custom fit was a welcome change,
as evidenced by the Crawford classification scale used by
the OT. The findings—40% of patients made an excellent affording more comfort, and reducing skin maceration and
recovery and 40% made a good recovery—are promising. blistering experienced with the generic Stack splint. Once
This is the first study to show a clinical benefit by supporting the 3D-printed splint was fitted, incidence of maceration
multiple patients in their recovery from mallet injury using and blistering was reduced. Patient feedback highlighted
a 3D-printed mallet splint. some modifications to improve the 3D-printed splint.
The study also shows an acceptance of a 3D-printed 4.2.1. Design of splint
mallet splint. Both patients and an OT confirmed they The design of the 3D-printed splint aimed to support the
would use the splint again if needed, with modifications. healing of the mallet injury while ensuring comfort of
These findings are encouraging and are helpful to expand using and clinical soundness of the splint. The outcomes
research in the use of 3D printing for mallet finger injuries of the study are positive clinically, but the following areas
going forward. However, it is important to note that mallet were highlighted for improvement: (i) air flow, (ii) securing
finger injuries tend to swell mostly during the first week to the finger, (iii) giving clearance to the PIPj, and (iv)
of injury, thus a generic Stack splint was used during that material used.
period in the current study. Patients may have reported
relief on the fitting of the 3D-printed mallet splint due to a Modern Stack splints are regularly perforated to
reduction of swelling and not solely due to the bespoke fit. allow air flow and increase comfort. Perforations were
not included in the 3D-printed splint for this study at the
Key areas of focus in this study were measuring finger request of the clinical expert who, based on their experience,
dimensions, patient requirements, design of the 3D-printed felt perforations in the splint encourage swelling through
splint, patient discharge advice and compliance, and the small perforations and can add to skin complications.
process. These are discussed in the following section Instead, a gap was left along the length of the splint to allow
along with key findings and recommendations for for airflow. Patients who found the 3D-printed splint too
further research.
hot had placed tape around the circumference of the splint
4.1. Measurements of finger dimensions and over this gap. Patients who placed a thin layer of tape
Calipers were used to measure each patient’s finger at the base of the splint reported no issues with airflow.
anthropometrics because they were available to the research Ventilation is a key element for comfort and to protect the
team and are an accurate measuring method. Moreover, skin. The design therefore needs to evolve to best facilitate

Volume 10 Issue 2 (2024) 526 doi: 10.36922/ijb.1963