Page 127 - IJB-9-2

International Journal of Bioprinting Design and manufacture of high-performance bone plate

screws might lead to insufficient stability of the plate skeleton by about 4% and reduces the stress shielding effect
system. Recent studies have demonstrated that the use of of the skeleton . Pobloth et al. designed honeycomb 3D
[10]
biological fixation (a combination of porous and solid) in titanium alloy grid scaffolds with different stiffnesses and
the structural design of a plate could dramatically improve compared bone growth and healing after changing the
its properties. Following the implantation of a biological stiffness of the scaffolds; the honeycomb titanium alloy grid
fixation plate at the bone site (in addition to satisfying the scaffolds reduced the stress shielding effect and promoted
aforementioned requirements), the interconnected holes in regenerative healing of macro-animal skeletons .
[11]
the plate offer space for the growth of new bones, making the Wang et al. established a mathematical expression for
plate and fracture site more firmly connected, reducing the the relationship between the porosity, the characteristic
contact area between the fracture site and plate, as well structural parameters, and the mechanical properties of
as facilitating the metabolic absorption of nutrients and typical porous structural units, laying a foundation for
bone healing. Designing and manufacturing personalized 3D printing of porous structural implants with gradient
biological fixation plates have become a research focus. modulus . Kanu et al. compared the curative effects
[12]
Parametric modeling is used to design biological of commercial titanium alloy fracture fixation plate and
fixation structures. The structural parameters (porosity, newly developed functionally graded artificial bone plate
surface-area-to-volume ratio, and mean pore size) of (isotropic hydroxyapatite). In the study, titanium materials
biological fixation structures can be adjusted by regulating were graded in the direction of thickness to treat femoral
[13]
input parameters, which offers convenience for designing fractures in children . Smith et al. manufactured a Ti-
new biological fixation plates . Additive manufacturing 6Al-4V extra low interstitial (ELI) plate using 3D printing
[4]
[14]
(AM or three-dimensional [3D] printing) technology is and applied it in clinical practice ; when a suture tape
a technology that slices and stratifies 3D models by using was tied between the first and second metatarsal bones, the
special software, obtains cross-sectional data, imports plate protected the second metatarsal bone and corrected
them into rapid prototyping equipment, and manufactures the hallux valgus.
solid parts by superposing materials layer-by-layer. There have been studies on the design, 3D printing, and
Through layer-by-layer superposition, it is feasible to manufacturing of biological fixation plates; however, only
manufacture parts with almost any geometric shape using a few reported the design and manufacturing of biological
AM technology. It has the advantages of processing single fixation plates based on 3D printing, combining shape
pieces, small batch, complex geometries, and compact optimization with topology optimization to achieve high
structure of finished parts. AM has provided a way to performance (mechanical properties and biocompatibility).
manufacture new biological fixation plates [5,6] . Selective Therefore, we investigate the design method and molding
laser melting (SLM) molding technology, on the other technology of personalized biological fixation plates.
hand, is a 3D printing technology based on laser melting
metal powder . 2. Materials and methods
[7]
Zhang et al. designed a plate with a lattice structure 2.1. Design constraints
for 3D printing based on topology optimization and finite The parts manufactured by 3D printing have higher degrees
element modeling technology . With the strength being of freedom than traditional manufacturing. However, this
[2]
ensured, the weight of the plate with lattice structure can does not mean that it is possible to mold parts with any
be reduced by about 40%, the thickness of the plate can geometry; designs that do not satisfy the design constraints
be modestly lowered, and the stiffness of the plate can be may lead to processing failure. Based on the findings on the
markedly decreased. Furthermore, a plate with a lattice biocompatibility of the geometric and porous structures of
structure can reduce the stress shielding effect of bone. SLM-molded parts, along with the actual applications of
Hu et al. contended that 3D-printed porous metal support the bone plate, the design constraints can be divided into
prostheses are accurate reconstructions for neoplastic bone four types [15,16] .
defects in the proximal tibia . Biomechanical support
[8]
under good biological integration can be achieved through (1) The constraint of sharp angle and thin wall:
careful preoperative design and intraoperative operation. considering that the laser spot adopted by SLM-molded
Li et al. studied the effects of the pore size, porosity, pore parts has a limiting focal size; it is impossible to manufacture
shape, and surface morphology of a 3D-printed porous parts whose sharp angle and thin wall are smaller than the
titanium alloy bone substitute on bone induction . Jia spot diameter; furthermore, it is challenging to guarantee
[9]
et al. found that the weight of the solid plate can be reduced the mechanical properties of thin-walled parts with small
by about 40% through lightweight design. The application wall thicknesses; they are prone to wear-and-tear and have
of porous bone plate increases the average stress of the no practical value.

Volume 9 Issue 2 (2023) 119 https://doi.org/10.18063/ijb.v9i2.658