Osteoarthritis of the knee (OAK) is a complex multi-factor disease resulting from mechanical abnormalities involving degradation of joints including articular cartilage and subchondral bone. OAK is often accompanied by joint pain and infection. A variety of causes is associated with OAK ranging from developmental, metabolic to mechanical deficits, in general leading to loss of cartilage.The project aims at the development of a mathematical model of cartilage homoeostasis for a better understanding of progressing OAK. The model will include the development of extracellular matrix depending on cell density, metabolism, nutrition gradients, growth factors and (via the collaboration with other projects within the Overload-PrevOp networks) the relation with biomechanical, regenerative, and infection effects.