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Zolfagharian, et al.
Effective use of AM may lead to a reduction in size costs associated and increases with the severity
and weight of the splint making it more comfortable or complexity of the injury . Although, in most
[10]
for the user. This paper presents an investigation cases, the patient will make a full recovery, often,
into the use of a fused deposition modeling (FDM) a long period of recovery is required, and some
printer to trial printing methods to produce a person will not recover full function and may potentially
and injury-specific mallet finger splint at a low-cost have a lasting disability (Figure 1). Mallet finger
and optimized weight and comfortability. is often left untreated by patients unless severe
restriction in extensor ability is present, or there
1.1 Mallet finger injury
is lingering pain . This injury, in the case, that
[11]
Mallet finger is the extremely common finger injury there are functional shortfalls, can impede the
where the fingers extensor ability is disrupted at its whole hand in everyday fine motor skill tasks.
terminal portion, causing an inability to extend at Furthermore, this deformity can develop additional
the distal interphalangeal joint . This disruption is medical conditions in the finger and hand as
[7]
either due to rupture of the fingers extensor tendon overcompensation can create hyperextension
or an avulsion fracture (fracture to the bone in a of proximal interphalangeal joint, a swan neck
location where a tendon or ligament attaches) deformity .
[7]
[8]
of the distal phalange. Swelling and tenderness The use of a movement restriction device called
can occur together with reduced ability to extend a splint is the common form of treatment for this
the distal phalanx, resulting in extension lag of injury. The splint is designed to hold the affected
anywhere from a couple of degrees up to several area of the finger in neutral or a small degree of
dozen. The cause can be either direct blow to the hyperextension while the tendon or avulsion
distal phalanx, sharp, or blunt injury to the distal fracture can heal.
interphalangeal joint . This injury is commonly
[9]
seen in ball sports such as Basketball, Volleyball, 1.2 Current mallet finger treatments
and Cricket. Injuries to the lower arm, including The conservative and post-surgical management
hand and wrist, are extremely common, accounting of mallet finger injuries require the use of splints
for 20% of all emergency presentations . to aid in recovery. Preventing any movement in
[10]
The economic burden for these injuries is the distal interphalangeal joint is crucial as flexion
extensive with the direct, indirect, and intangible of the joint will separate the torn ends of the

tendon or avulsion fracture, halting the recovery
A B
process. In this case, the finger would need to be
returned to full extension, and the healing process
would start again from the beginning. There are
several types of splints that can be used for this
condition; the three commonly used splints are
the stack (prefabricated), dorsal aluminum, and
Figure 1. (A) Mallet finger fracture (Image personalized thermoplastic splints (Figure 2).
courtesy from Sachin J Shah, MD, online), Beyond the use of the dorsal aluminum splint,
(B) anatomy of finger . there are specifically designed mallet finger splints
[12]

A B C

Figure 2. (A) Stack, (B) dorsal aluminum, and (C) personalized thermoplastic splints .
[13]
International Journal of Bioprinting (2020)–Volume 6, Issue 2 17