When you have a joint in your body that is arthritic it is painful to move that joint. The body tries to prevent joint mobility by forming bone spurs around the joint to limit the range of motion. The body is essentially trying to fuse the joint that is painful.
Surgically going in and removing the bone spurs does not help because the body will quickly reform the bone spurs after they have been surgically excised. Imaged below is a picture of a foot. The great toe has a significant amount of bone spurs. The red circle shows the great toe joint with all the bone spurs and narrowed joint space. The third toe,with the yellow circle, shows a normal looking joint. This patient has almost no motion at her great toe joint.