Normally, the ends of the bones are covered by cartilage, which normally cushions and allows smooth movement. When cartilage wears out and does not repair, the underlying bone is exposed, causing pain. Cartilage has no direct blood or nerve supply, so any damage is usually permanent. Typical symptoms include joint pain, swelling, stiffness (especially after rest), and reduced flexibility. While anyone can develop osteoarthritis, it’s most common in older adults and those with previous joint injuries or excess body weight.