2022, Vol. 26 ›› Issue (28): 4429-4434

Design and optimization of artificial femoral unit cell structure based on response surface methodology

Lian Tingting1, Chen Xuewen1, Zhang Bo1, Wang Guangxin1, Akiyoshi Osaka1, 2   

Abstract: BACKGROUND: Artificial bone implantation is an important method for the treatment of severe osteoporosis and bone injury. However, the mechanical compatibility with the host bone should be considered during the implantation, especially to match the Young’s modulus of the artificial bone with the host bone.
OBJECTIVE: To analyze the influence of the structure type, pillar size and aperture size on Young’s modulus and porosity of cell structure.
METHODS: Three types of unit cell structures (pillar, perforated plate, cylindrical aperture) that described the microstructure of bones were designed. Orthogonal experiments were designed. The unit cell structure was statically analyzed based on finite element simulation. The range analysis and variance analysis were used to study the influence of three types of unit cell structure, pillar size and aperture size on the Young’s modulus and porosity of the unit cell structure. Based on the orthogonal experimental data, a response surface approximate model was established. The Young’s modulus of the cancellous bone of the proximal femur was taken as the optimization target. The sequential quadratic programming method was selected to optimize the parameter design of the unit cell structure.
RESULTS AND CONCLUSION: The results of range analysis and variance analysis showed that the primary and secondary order of the above three factors affecting Young’s modulus was: pillar size > aperture size > structure type, and the primary and secondary order affecting porosity was: pillar size > structure type > aperture size. In addition, the response surface method was used to establish the approximate model, and the sequence quadratic programming method was adopted to optimize the unit cell structure with the Young’s modulus of femur 0.97 GPa as the optimization objective, and then the simulation verification was carried out. The results show that the optimal design method is effective, which provides a new design method for artificial bone structure.
Key words: femur, artificial bone, unit cell structure, finite element analysis, compression properties, orthogonal test, optimization design