Study On Personalized Design Method And Verification Of Total Knee Prosthesis Manufactured By 3D Printing Technology

Personalized knee prosthesis is a concept that has emerged in recent years with the development of advanced manufacturing technology and advanced design concepts.The goal of the personalized knee prosthesis is to provide patients with customized prosthesis as well as personalized surgery.However,how to achieve a high degree of match after prosthesis implantation and reconstruction of the patient’s normal knee flexion is the key issue in the design of personalized knee prostheses.This paper proposed a personalized design method of knee prosthesis based on 3D printing technology and reverse design method,analyzed the rationality of that design method,and explored the design effects of different design schemes through simulation analysis and prosthesis implantation experiments.The main research contents and conclusions are as follows:1 、 Research on personalized design principles and design methods of knee joint prostheses.By analyzing the structure and function of the knee joint and prosthesis,two main principles of personalized design are determined in this paper: First,the personalized prosthesis should have a good match with the knee,not only on the coverage of osteotomy surface,but also on the appearance of prosthesis;Second,prosthesis should to restore the normal flexion process and individual needs of patients.The personalized design of the prosthesis should be a combination method of reverse design and forward design.2、The matching of the knee prosthesis has been analyzed.The concepts of over coverage rate and under coverage rate were proposed which based on the concept of osteotomy coverage rate,to measure the degree of matching of the prosthesis on the osteotomy surface.At the same time,the concept of coincidence degree,over-coincidence degree and under-coincidence degree of the prosthesis were proposed to measure the matching of the femoral prosthesis in appearance.Prosthesis implantation experiment was conducted by computer simulation,and the coverage rate and coincidence degree of both the commercial knee prostheses and the personalized knee prostheses were measured and calculated.The results showed that the individualized knee prosthesis was significantly better than the commercial prosthesis on both the osteotomy surface and the appearance.3、Verification experiment of personalized knee prosthesis on cadaver specimen.Metal 3D printing is used to process femoral component and tibial component,and 3D printing by plastic is used to process the polyethylene component.The personalized knee prosthesis was implanted into the cadaveric body,and the prosthesis matching effect is ideal,the lower limb force line reconstruction effect is good,knee flexion is normal,which verified the rationality of the design and processing methods in this study.4、Analysis of reconstruction effect in the process of knee flexion before and after prosthesis implantation.Through the binocular vision motion analysis equipment,this article analyzed the knee flexion before and after the implantation of personalized knee prostheses for different tibial-femoral articular surface design solutions.The results showed that asymmetrical patello-femoral articular surface can effectively reconstruct the femoral valgus movements during flexion.However,both symmetric and asymmetrical tibial-femoral articular surface designs would reduce the range of internal and external rotation of the femur.