<qa>  What is the most common type of arthritis?Osteoarthritis OA is the most common kind of arthritis. OA is called degenerative arthritis, is a disease that results from the breakdown of cartilage in joints, leading to joint pain and damage. OA is very variable and there are lots of different types affecting different joints. This degenerative disease primarily affects the large, weight bearing joints including the knees, lower back, hips, neck and the feet and the joints in the hands. In OA, the disease begins with the degeneration of the cushion of cartilage between the joints. As it degrades, the synovium and the ends of the bones thicken, resulting in the pain and stiffness associated with arthritis. The progressive cartilage deterioration is followed by hardening of the joints due to calcification and bone spur formation. Treatment generally involves a combination of exercise, lifestyle modification and analgesics. If pain becomes debilitating joint replacement surgery may be used to improve the quality of life. 