Metals have been used for orthopedic implants for a long time due to their excellent mechanical properties. With the rapid development of additive manufacturing (AM) technology, studying customized implants with complex microstructures for patients has become a trend of various bone defect repair. A superior customized implant should have good biocompatibility and mechanical properties matching the defect bone. To meet the performance requirements of implants, this paper introduces the biomedical metallic materials currently applied to orthopedic implants from the design to manufacture, elaborates the structure design and surface modification of the orthopedic implant. By selecting the appropriate implant material and processing method, optimizing the implant structure and modifying the surface can ensure the performance requirements of the implant. Finally, this paper discusses the future development trend of the orthopedic implant.

In order improve the poor mechanical properties of the body-centred cubic (BCC) lattice structure, which suffers from the stress concentration effects at the nodes of the BCC unit cell, a graded-strut design method is proposed to increase the radii corner of the BCC nodes, which can obtain a new graded-strut body-centred cubic (GBCC) unit cell. After the relative density equation and the force model of the structure are obtained, the quasi-static uniaxial compression experiments and finite element analysis (FEA) of GBCC samples and BCC samples are performed. The experimental results show that for the fabricated samples with the same relative density, the GBCC can increase the initial stiffness by at least 38.20%, increase the plastic failure strength by at least 34.12%, compared with the BCC. Coupled experimental and numerical results not only suggest that the GBCC has better mechanical and impact resistance properties than the BCC, but also indicate that as the radii corner increases, the stress concentration effect at the node and the mechanical properties will be improved, which validates the proposed design method for graded-strut unit cells and can provide guidance for the design and future research on ultra-light lattice structures in related fields.

Since the advantages of precise operation and effective reduction of radiation, robots have become one of the best choices for solving the defects of traditional fracture reduction surgery. This paper focuses on the application of robots in fracture reduction surgery, design of the mechanism, navigation technology, robotic control, interaction technology, and the bone–robot connection technology. Through literature review, the problems in current fracture reduction robot and its future development are discussed.

This paper presents the mechanical design, dynamics analysis and ankle trajectory analysis of a prosthetic knee joint using the geared five-bar mechanism. Compared with traditional four-bar or six-bar mechanisms, the geared five-bar mechanism is better at performing diverse movements and is easy to control. This prosthetic knee joint with the geared five-bar mechanism is capable of fine-tuning its relative instantaneous center of rotation and ankle trajectory. The centrode of this prosthetic knee joint, which is mechanically optimized according to the centrode of human knee joint, is better in the bionic performance than that of a prosthetic knee joint using the four-bar mechanism. Additionally, the stability control of this prosthetic knee joint during the swing and stance phase is achieved by a motor. By adjusting the gear ratio of this prosthetic knee joint, the ankle trajectories of both unilateral and bilateral amputees show less deviations from expected than that of the four-bar knee joint.