Arthritis is inflammation of one or more of joints and may cause pain, swelling and stiffness, making it difficult to do everyday activities, such as walking or climbing stairs. Osteoarthritis is the most common form of arthritis in the knee. It is a degenerative, “wear-and-tear” type of arthritis that occurs most often in people 50 years of age and older, but may occur in younger people, too.
With osteoarthritis, the cartilage in the knee joint gradually wears away. As the cartilage wears away, it becomes frayed and rough, and the protective space between the bones decreases. This can result in bone rubbing on bone and cause painful bone spurs. Osteoarthritis develops slowly, and the pain it causes worsens over time.