The effect of collagen fibril orientation on the biphasic mechanics of articular cartilage.
The highly inhomogeneous distribution of collagen fibrils may have important effects on the biphasic mechanics of articular cartilage. However, the effect of the inhomogeneity of collagen fibrils has mainly been investigated using simplified three-layered models, which may have underestimated the effect of collagen fibrils by neglecting their realistic orientation. The aim of this study was to investigate the effect of the realistic orientation of collagen fibrils on the biphasic mechanics of articular cartilage. Five biphasic material models, each of which included a different level of complexity of fibril reinforcement, were solved using two different finite element software packages (Abaqus and FEBio). Model 1 considered the realistic orientation of fibrils, which was derived from diffusion tensor magnetic resonance images. The simplified three-layered orientation was used for Model 2. Models 3-5 were three control models. The realistic collagen orientations obtained in this study were consistent with the literature. Results from the two finite element implementations were in agreement for each of the conditions modelled. The comparison between the control models confirmed some functions of collagen fibrils. The comparison between Models 1 and 2 showed that the widely-used three-layered inhomogeneous model can produce similar fluid load support to the model including the realistic fibril orientation; however, an accurate prediction of the other mechanical parameters requires the inclusion of the realistic orientation of collagen fibrils.
Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, UK. Electronic address: Q.Meng@leeds.ac.uk.
Qingen
Q
Meng
Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, UK.
Shuqiang
S
An
Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, UK; School of Physics and Astronomy, University of Leeds, UK.
Robin A
RA
Damion
Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, UK; School of Mechanical Engineering, Xi'an Jiaotong University, China.
Zhongmin
Z
Jin
Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, UK.
Ruth
R
Wilcox
Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, UK.
John
J
Fisher
Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, UK.
Alison
A
Jones
D002358:Cartilage, Articular / Q000473:pathology*; D003094:Collagen / Q000502:physiology* / Q000648:ultrastructure; D005109:Extracellular Matrix / Q000648:ultrastructure*; D020342:Finite Element Analysis; D006801:Humans; D008954:Models, Biological
D003094:Collagen
Articular cartilage; Biomechanics; Collagen fibril; DT-MRI; Fibril-reinforced biphasic model