Development and prevention of knee osteoarthritis: The load of obesity

According to the World Health Organization, more than 150 million (± 2.5%) people suffer from osteoarthritis (OA ) worldwide. Above the age of 60 years, these figures even rise to 10% 2. In almost 30% of these cases, OA leads to moderate to severe disability. Thereby, it is the most common joint disease for the middle-aged and older population In the Netherlands, OA is estimated to affect more than 650.000 people. Annual health care costs associated with OA are estimated to be 540 million euro, equivalent to 0.8% of the total costs of health care in the Netherlands. Before, OA was thought of as being mainly driven by wear and tear of the articular cartilage within the synovial joint. In recent years, it is shown that not only cartilage, but also the subchondral bone, ligaments, the synovial fluid, and surrounding muscles are involved in the OA process. Although the exact aetiology is still unknown, OA is in general characterized by loss of articular cartilage, osteophyte formation, and subchondral bone sclerosis. Clinically, OA is characterized by joint pain and limited joint function. OA can affect all synovial joints, but is most common in the knee, the hip and the hand joints. Given the predominance of OA in the knee joint compared to other joints, the main focus in scientific studies have been on the knee joint, as is the current thesis.