Page 455 - IJB-10-1

International Journal of Bioprinting Efficacy of 3D-printed customized titanium implants

Table 1. Chemical composition of Ti-6Al-4V alloy powder
Element H C O N Fe Al V Ti
Content (wt.%) 0.003 0.005 0.14 0.009 0.22 6.49 4.00 Bal

for orthopedic internal fixation. Three-dimensional (3D)
printing is a new rapid prototyping technology in the
additive manufacturing (AM) industry. As an excellent
biomaterial, Ti-6Al-4V alloys is frequently applied in
metal 3D printing process in medical area. 3,4

The application of 3D printing technology in
orthopedics is rapidly progressing and mainly focuses
on five aspects: 5-11 (i) preparation of lesion model and
3D display of complex lesion structure, which would
help surgeons improve the surgical plan and enable
better preoperative communication with the patients;
(ii) preparation of customized guide plates to assist the
positioning during surgery, thereby reducing surgical
trauma and saving the operation time; (iii) preparation Figure 1. Morphology of Ti-6Al-4V alloy powders (scanning electron
of customized protective gears and rehabilitation microscope, 200× magnification).
supplies, which would improve the outcome compared
with traditional treatment such as cast immobilization; 2. Material and methods
(iv) preparation of grafts implanted intraoperatively 2.1. Materials preparation
in patients to overcome the deficiencies of using The Ti-6Al-4V spherical metal powder was produced
volume-produced products; and (v) direct printing with plasma rotating electrode process by Northwest
of cell–material complexes, which would simplify Institute for Nonferrous Metal Research, and the
the construction process of engineered tissues and chemical composition of Ti-6Al-4V alloy powder is listed
organs. Among them, the application of 3D-printed in Table 1. The Ti-6Al-4V powder was spherical and the
orthopedic implants has been applied in the clinic, particle size was in the range of 40–180 µm (Figure 1 and
such as spinal fusion cages, acetabular cups, knee Table 1).
joints, etc. These 3D-printed implants have received
certifications of Conformité Européenne (CE), Food 2.2. Establishing the technical path of 3D-printed
and Drug Administration (FDA), and China Food and customized titanium implants
Drug Administration (CFDA). As of 2017, more than We used Ti-6Al-4V spherical metal powder as raw
one hundred thousand 3D-printed acetabular cups have material and used selective electron beam melting
been implanted in the clinical setting globally. However, (SEBM), a type of metal 3D printing technology, to
rare applications have been reported in ankle surgeries. prepare titanium alloy implants. 17-19 The designed

Foot and ankle disease is very common in orthopedics. implant model was processed into a layer with a
In surgery, it is often necessary to choose internal fixation thickness of 70 μm, and then imported into the SEBM
or bone grafting to maintain the anatomical position of the machine (model Arcam A2, Arcam, Sweden). The main
bone or joint. 12-16 Unfortunately, there are very few types technical parameters are shown in Table 2. The baseplate
of internal fixation available for surgeons to choose from. used was a stainless steel plate with the size of 210 ×
They are limited to a small number of screws and plates, 210 × 10 mm. Figure 2 shows the schematic diagram
which are extremely unfavorable for accurate treatment. of the molded sample models, which include six plates
As a new rapid prototyping technology, 3D printing has for tibiotalocalcaneal (TTC) arthrodesis and two sets of
created conditions for solving this problem. fusion cages in different sizes for subtalar arthrodesis.
In order to further improve the quality of the implants,
This study focused on the feasibility of using 3D hot isostatic pressing (HIP) was conducted under a
printing technology to prepare customized titanium temperature of 930°C and a pressure of 100 MPa, which
implants and apply them to more complex foot and ankle were maintained for 2 h. The finished implants are
surgeries. Follow-ups were conducted to observe the short- shown in Figure 3. Implants were sealed after ethylene
term efficacy. oxide sterilization for intraoperative use.

Volume 10 Issue 1 (2024) 447 https://doi.org/10.36922/ijb.0125