Using 3D finite element models verified the importance of callus material and microstructure in biomechanics restoration during bone defect repair

摘要

Background: There is lack of further observations on the microstructure and material property of callus during bone defect healing and the relationships between callus properties and the mechanical strength. Methods: Femur bone defect model was created in rabbits and harvested CT data to reconstruct finite element models at 1 and 2months. Three types of assumed finite element models were compared to study the callus properties, which assumed the material elastic property as heterogeneous (R-model), homogenous (H-model) or did not change from 1 to 2months (U-model). Results:The apparent elastic moduli increased at 2months (from 355.58 +/- 132.67 to 1139.30 +/- 967.43MPa) in R-models. But there was no significant difference in apparent elastic moduli between R-models (355.58 +/- 132.67 and 1139.30 +/- 967.43MPa) and H-models (344.79 +/- 138.73 and 1001.52 +/- 692.12MPa) in 1 and 2months. A significant difference of apparent elastic moduli was found between the R-model (1139.30 +/- 967.43MPa) and U-model group (207.15 +/- 64.60MPa) in 2months. Conclusions: This study showed that the callus structure stability remodeled overtime to achieve a more effective structure, while the material quality of callus tissue is a very important factor for callus strength. At the meantime, this study showed an evidence that the material heterogeneity maybe not as important as it is in bone fracture model.