Originally described as a chronic degenerative disease of joint cartilage, osteoarthritis (OA) affects nearly 27 million people in the United States and is one of the most prominent causes of debilitating pain in the knees and other joints. Cartilage is a tough, flexible tissue that cushions the movement of bones within a joint, such as the knee or wrists. As cartilage breaks down, bone-on-bone contact can occur, leading to severe pain and joint stiffness.
OA is not strictly caused by cartilage degeneration, but rather by an overall disruption of biological mechanisms that control the balance between joint damage and repair. While cartilage damage is indeed prominent in OA; bone lesions, a malfunctioning inflammatory response, as well as bone and cartilage overgrowth can also contribute to this disease.
Overuse and injury to the knee and other joints are the biggest risk factors for OA development. Although OA can affect people at any age, a lifetime of “wear and tear” of their joints causes OA to be far more prevalent in the elderly. Gender is also an important risk factor of OA. At younger ages, less than 55, OA affects men and women equally; however, with increasing age, a greater amount of women suffer from this disorder. By causing tremendous strain on joints, especially the knees, obesity or excessive body weight are also a major risk factor for OA. The high obesity rates in the US, according to the Center of Disease Control (CDC), may cause OA incidence to double by 2020.