All of those options are possible. In fact, you may want to use them all one at a time. Usually the wait-and-see approach is accompanied by an exercise program to keep the muscles around your knee toned and strong. Some of the medications available control both the pain and the disease.
If the joint starts to deteriorate more, then surgery to keep the joint surfaces clean and smooth may be the next step. The doctor may put a special fluid called hyaluronan in the joint to keep the tissue from sticking together.
When the joint space narrows too much and the bone is in danger of rubbing against bone, a joint replacement will be needed. Today's treatment approach for osteoarthritis is to save the bone and joint for as long as possible. Taking it one step at a time is a good way to accomplish this goal.