On the modeling of cartilage mechanics, damage and adaptation

Articular cartilage transfers significant loads from one bone to another, while we use our articulating joints to walk, run and jump. It allows us to do so day after day for many decades, while it doesn’t have significant repair capacity in case damage would occur. It is not surprising that in many cases damage does occur and this damage generally progress es into degenerative osteoarthritis, a socio-economically important, painful and disabling disease. To understand better how our daily activities translate to joint damage and osteoarthritis requires a multi-level approach that goes from total body level d own to join, tissue and cell biological level. One of the future targets should be to combine studies from these various levels and to bridge the gaps between them. Inspired by the remarkable mechanical properties of the cartilage tissue itself, we have explored the principles of cartilage mechanics by developing and using a composition-based numerical model. This means that the properties of the cartilage in the model are determined by the content and structure of swelling proteoglycans and collagen fiber reinforcement. This model is presently being adopted to study how joint degeneration as well as tissue development, adaptation and ultimately repair would occur, depending on the mechanical conditions in the joint. Starting from the cartilage tissue level, we are also extending our work towards both the cellular and the joint level. This presentation will discuss advantages and opportunities of our approach, as well as limitations and challenges that we’re facing when extending towards the larger levels. Finally, it will provide an outlook into the future directions and applications of this type of modeling.