چكيده به لاتين
It has been experimentally proposed that the discrete regions of articular cartilage along with different subchondral regions, known as the bone-cartilage unit, are biomechanically altered during osteoarthritis degenerations. However, a validated computational framework capturing all of the dominant changes in multiphasic parameters has not yet been developed. In this study, a new validated finite element model is proposed which is a combination of several previously well-established nonlinear, depth-dependent, fibril-reinforced swelling finite element models in order to improve the accuracy and functionality of the simulations. Then, some simulations are conducted by means of the dominant parameters in accordance with recent research and computational implementations of unconfined compression and indentation compression tests. In addition to geometrical variations due to fibrillation and permanent split line torsions, the aforementioned dominant parameters include proteoglycan depletion, collagen fibrillar softening, permeability and fluid fraction increase for approximately non-advanced osteoarthritis. The results depict the importance of subchondral bone tissues in fluid distribution within the bone-cartilage unit by decreasing the fluid pressure and permeation during osteoarthritis. Furthermore, the osteoarthritis composition-based studies shed light on the significant biomechanical role of the calcified cartilage in stress contributions, together with fluid and osmotic pressure alterations and insignificant role of minor fibrillar abnormalities in load sharing of subchondral bone constituents. We conclude that subchondral bone discrete parts play a key role in the pathogenesis of osteoarthritis. Nevertheless, minor fibrillar abnormalities that are not in the deep zone of articular cartilage have a regional degenerative effect, although a negligible influence on the subchondral bone tissues.
