Osteoarthritis -- also known as degenerative joint disease -- is a form of arthritis caused by the degeneration of cartilage. Cartilage serves an important role in joint function, providing protection to the ends of joints by acting as a shock absorber. Without the cartilage in the joint, bone rubs against bone leading to pain, deformity, inflammation, and limitation of motion in the joint. X-rays usually indicate a narrowing of the joint. Natural support options for the joints include glucosamine, chondroitin and choline.