## 4 Discussion  
Postoperative experimental evaluations of tibial implants used in HTO procedures have rarely been conducted due to a series of limitations, most notably the inability to perform in vivo experiments on human bone. This study utilized porcine bone, which shares the same heterogeneous structure (including cancellous and cortical bone) as human bone, for postoperative experimental assessments. A three-dimensional model replicating the internal structure of actual porcine tibia was constructed, and its stress distribution under compressive conditions was analyzed through finite element analysis. The use of porcine bones as substitutes for human bone models in biomechanical studies represents a common practice when human specimens present ethical challenges and accessibility limitations. However, this approach does carry inherent constraints, such as the generally lower bone density of porcine specimens compared to human bone and the morphological differences between porcine and human tibiae. Nevertheless, this study focuses on developing a method for personalized customization of bone implants. Considering the significant morphological variations among individual human bones, the mechanical testing results from porcine models have already demonstrated that constructing authentic tibial geometric models based on CT scan data substantially enhances the correlation between simulation outcomes and biological reality. Therefore, the adoption of porcine models does not compromise the applicability of this methodology. The stress distribution on the tibia exhibited relatively uniform variations within the loaded region, with areas of higher equivalent stress concentrated beneath the tibial plateau. The equivalent stress nephogram of the tibial cross-section reveals that due to distinct material properties between cortical and cancellous bone--particularly the significantly higher Young's modulus of cortical bone compared to cancellous bone--the cortical bone bears the majority of loads transmitted from the tibial plateau, making it the primary load-bearing  
Figure 8: Force–displacement curves of the tibia following implantation of porous tibial prostheses with varying porosity levels: (**a**) hybrid pore structure; (**b**) square pore structure; (**c**) circular pore structure. (**d**) Maximum displacement value of tibial compression test after HTO surgery. component in the tibial structure during physiological activities. The stress nephogram demonstrates dense stress concentration zones throughout the cortical bone, particularly in the upper-middle region of the tibia, while the cancellous bone, characterized by its porous structure and lower modulus, only sustains minimal dispersed loads. Mechanical testing displacement data showed close agreement with finite element simulation results, validating that obtaining precise tibial geometry through CT scanning and differentiating bone regions in the finite element model can better simulate the mechanical responses of real tibia under physiological conditions. The established finite element model of tibial mechanics demonstrates enhanced accuracy, providing effective guidance for subsequent design of tibial spacers. Both the finite element simulation displacement nephogram and the DIC nephogram from in vitro mechanical tests exhibited a superimposed state from distal to proximal regions, with maximum displacement observed at the proximal tibia gradually decreasing towards the distal end. Finite element simulation results of equivalent stress distribution demonstrate relatively uniform stress variations across loaded tibial regions, with elevated equivalent stress concentrations primarily localized beneath the tibial plateau. As physiological activity intensity escalates, corresponding to increased loading magnitudes from 375 N to 1500 N, the maximum equivalent stress in the tibia displays a progressive elevation, increasing from 3.94 MPa during standing to 15.76 MPa during running.