Numerical modeling of acetabular reconstruction cages made of composite material and estimation of mechanical behavior for bone and cage

Abstract

Owing to the population aging, it is expected that the number of patients undergoing acetabular bone and hip joint disease will increase. A total hip arthroplasty (THA) is one of the treatments for serious disease of hip joint. However, in the situation of massive acetabular bone loss, an acetabular reconstruction cage is additionally needed to reconstruct the hip joint. In this study, we focus on the acetabular reconstruction cage. The conventional cage is mainly made of metal. However, due to the lack of mechanical biocompatibility, there is a serious problem of 'stress shielding' of metal. The acetabular reconstruction cage made of CFRP could be possible to reduce the stress shielding, but the applicability for strength should be guaranteed. Therefore, the purpose of this study is to develop a numerical modeling method for acetabular reconstruction cage, and estimate the mechanical behaviors of bone and the cage. According to the numerical simulation, relative displacement of CFRP cage to bone was almost the same as Ti-6Al-4V cage. Moreover, strain energy density of CFRP was higher than Ti-6Al-4V in a wide range. Therefore, it was concluded that CFRP enables to design acetabular reconstruction cage which is more excellent for restraint of bone atrophy and promotion of bone remodeling than ready-made without influence on micromovement.