What is cartilage?
Cartilage is a firm, rubbery material that covers the ends of bones in normal joints. Its main function is to reduce friction in the joints and serve as a “shock absorber”. The shock absorbing quality of normal cartilage comes from its ability to change shape when compressed. Cartilage can change shape because it contains more than 70 percent water, which can be redistributed with movement. For example, when force is applied to a knee, as in standing or walking, some water from cartilage enters the joint and coats the cartilage. When the force is no longer present, such as when you sit down, the water is reabsorbed and the cartilage regains its normal shape. Because cartilage does not contain nerves, you do not feel pain when these changes in shape occur.
Osteoarthritis causes the cartilage in a joint to become stiff and lose its elasticity, making it more susceptible to damage. Over time, the cartilage may wear away in some areas, greatly decreasing its ability to act as a shock-absorber. As the cartilage wears away, tendons and ligaments stretch, causing pain. If the condition worsens, the bones could rub against each other. Osteoarthritis usually is treated with medications, exercise, applying heat and cold to the painful joint, use of supportive devices such as crutches or canes, and controlling one’s weight. Surgery may help relieve pain when other treatment options have not been effective.
The goals of treatment are to decrease joint pain and stiffness, improve joint mobility and stability, and increase the ability to perform daily activities. The common treatment methods previously listed do not change the progression of osteoarthritis. Because the breakdown of cartilage is a significant part of osteoarthritis, researchers have been focusing their efforts on finding agents to prevent this breakdown. Glucosamine and chondroitin sulfates are two nutritional supplements currently being studied to determine their usefulness in treating osteoarthritis.