A joint is where two or more bones come together, like the knee, hip, elbow or shoulder. Joints can be damaged by many types of injuries or diseases. Arthritis or simply years of use may cause a joint to wear away. This can cause pain, stiffness and swelling. Over time, a swollen joint can become severely damaged.
Treatment of joint problems depends on the cause. If you have a sports injury, treatment often begins with the RICE (Rest, Ice, Compression and Elevation) method to relieve pain, reduce swelling and speed healing. Other possible treatments include pain relievers, keeping the injured area from moving, rehabilitation, and sometimes surgery. For arthritis, injuries, or other diseases, you may need joint replacement surgery to remove the damaged joint and put in a new one.
NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases