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International Journal of Bioprinting Macro and micro structure of a 3D-printed implant

Table 2. Result of FE mesh convergence test
Element size of bone Element size of implant Total number of Maximum of model total Maximum value of 1st principal
(mm) (mm) elements deformation (mm) stress (MPa)
3.5 2.5 53,381 0.466370346 43.09854468
2.8 2.0 83,842 0.462659744 54.06405693
1.8 1.4 254,998 0.454711458 60.30253952
1.2 0.8 846,132 0.451476180 55.76232215
1 0.5 1,621,794 0.448825515 56.67746388
Error % (between 1.2 mm Error % (between 0.8 mm <2% <2%
and 1 mm) and 0.5 mm)

Figure 2. Finite element high tibial osteotomy mesh patterns using wedge system, including solid wedge and optimized wedge in left part and using plate
system in right part.

achieve a lightweight design while maintaining the pore sizes ranging from 500 to 800 μm (average 700 μm),
optimal solid WS structure distribution. The topology based on relevant literature. 6,26 This approach led to the
optimization outcomes, indicating regions suitable for development of a novel bone-filled WS with a biomimetic
material removal, were then utilized in the CAD software microstructure, as depicted in Figure 4a.
SpaceClaim to reconstruct the bone-filled WS structure
(Figure 3b and c). Based on the topology optimization 2.3. Finite element analysis
results, the posterior region was identified as the area for The T plate and screws were assembled and fixed onto
bone filling using biomimetic lattices. The YM lattice with the previous osteotomy tibia model in the CAD software
unit cell size 2.6 mm, known for its widespread use and according to clinical requirements to understand the
suitability for bone growth, was selected as the unit cell mechanical effects from using a WS with embedded screws
and integrated into the design using 3-Matics software compared to a traditional T plate fixation in HTO. Four
(Materialise NV, Leuven, Belgium). The lattice design screws were fixed above the osteotomy surface, while five
parameters were tailored to promote bone ingrowth, screws were fixed onto the bone shaft below the osteotomy
with a porosity range of 65%–75% (average 70%) and surface (Figure 4d). The model was then input into FE

Volume 10 Issue 1 (2024) 496 https://doi.org/10.36922/ijb.1584