This condition is fairly frequent nowadays, as wear and stress on the joints can cause cartilage degradation over time. This can happen to anyone, although it is more common in the elderly. Because of cartilage deterioration, bones lose their stiffness. They lose their ability to brush against each other within the joint. As a result, the joint becomes inflamed and painful, resulting in decreased mobility. Bone spurs may develop around the joint as well. As arthritis progresses, muscles and ligaments may become weak and stiff.