Investigation of mechanical behavior of CPC/bone specimens by finite element analysis

Calcium phosphate cement (CPC), as an important injectable biomaterial, is extensively used for bone repair in clinical application. If mechanical properties of CPC match well with that of bone tissue, it can create an appropriate mechanical environment for bone repair. In our study, the objective was to investigate the responses of bone tissue to CPC in different series of elastic modulus combinations. Finite element analysis (FEA) was applied to calculate the stress/strain on CPC-bone specimens and to further forecast the potential risky area. The predicted results indicated that CPC materials and bone tissue had different stress distribution patterns under the same loading condition. For CPC material, the Von Mises Stress peak occurred in the bone-cement joint area; while for bone tissue, the risky area was located at the bridge area among trabecular bones. The porous and loose structure of cancellous bone induced a greater Von Mises Stress in bone tissue. Quantitative analysis indicated that stress/strain distribution was directly correlated with the elastic modulus of material. When Young's modulus of bone and CPC was 1 GPa and 6.10 GPa respectively, the optimal stress matching between bone and CPC was achieved. In sum, this work confirmed that FE modeling was the ideal method for predicting fracture behavior of bone-CPC specimen both qualitatively and quantitatively.