Osteoarthritis is also called as degenerative joint disease; this is the most common type of arthritis, which occurs often in older people. This disease affects cartilage, the tissue that cushions and protects the ends of bones in a joint. With osteoarthritis, the cartilage starts to wear away over time. In extreme cases, the cartilage can completely wear away, leaving nothing to protect the bones in a joint, causing bone-on-bone contact. Bones may also bulge, or stick out at the end of a joint, called bone spurs.
Osteoarthritis causes joint pain and can limit a person's normal range of motion (the ability to freely move and bend a joint). When severe, the shoulder joint may lose all movement, making a person disabled.