The human skeletal system performs essential functions, such as support, protection, and movement, in daily life. The performance of these functions is closely related to the external anatomical morphology and internal porous structure of bone tissue. When patients suffer from bone defect repair, custom-made prostheses with multiple advantages, such as morphological adaptation, performance matching, and functional restoration, can achieve accurate and personalized treatment through biomimetic design and 3D printing technology; these approaches have gradually been applied and recognized. As shown in Fig. 2.1, the clinical applications of 3D-printed porous prostheses have been demonstrated. The rational design of the porous structures for these custom-made prostheses can effectively overcome existing problems associated with conventional metal prostheses after implantation, such as stress shielding and the weak bonding strength of bone/prosthesis interfaces. Hence, the potential risk of prosthesis loosening and fracture is reduced, which is an important benefit for bone defect repair and functional restoration.