This study presents a numerical investigation of the permeability of porous implants with unit cells in the form of truncated cube, diamond, body-centered cubic (BCC), and tesseract geometries. Initially, the porous scaffolds were designed using SolidWorks software, and then numerical simulations were performed using ANSYS Fluent. The simulation outputs included pressure contours, velocity contours, and streamlines. The permeability of the scaffolds was calculated based on the pressure drop values, fluid properties, and structural parameters of the scaffolds under three different conditions: variations in inlet velocity, differences in unit cell geometry, and a comparison between Newtonian and non-Newtonian flow models. For modeling non-Newtonian flow, the Cross and Carreau flow models were used. The primary advantage of these models is their ability to accurately predict viscosity behavior across a wide range of shear rates, including regions of constant viscosity at very low and high shear rates. The obtained results showed that, in the constant viscosity regime, the scaffolds with the Split-P and Gyroid unit cells exhibited the highest and lowest permeability values of 1.11 × 10^(-8) m² and 0.18 × 10^(-8) m², respectively. Therefore, the Split-P unit cell is more suitable than the other unit cells for the design and fabrication of bone implant geometries. It was also observed that the inlet velocity had no significant effect on scaffold permeability. According to the results, in all types of unit cells, the fluid modeled using the Cross model experienced a higher pressure drop compared to the Carreau model and the constant-viscosity (Newtonian) model.