Micro-environmental and macro-environmental improvement of joint quality in knee joint pathologies

The knee joint is a complex joint and homeostasis in this joint can be disturbed by various conditions such as a cartilage defect or osteoarthritis, leading to a reduced 'knee joint quality'. This thesis demonstrates new insights in improving this 'knee joint quality' at the cellular, tissue and joint level. The thesis describes the molecular mechanisms involved in the improvement of the chondrocyte phenotype which may aid in treatment strategies of cartilage repair. It is also shown in this thesis that Hoffa's fat pad, a tissue located in the knee joint, can contribute to local inflammation in the knee joint, which can be treated with the drug Celecoxib. In addition, this drug can be incorporated into an innovative intra-articular drug delivery system, which is an attractive new strategy to improve knee joint quality on the long term. Finally, this thesis shows the presence of tissue type-dependent osteoarthritis-specific proteins in the synovial fluid of the knee joint. These proteins can be used as biomarkers to help develop treatment strategies for cartilage repair or to slow down the process of knee osteoarthritis.