This also can be called wear and tear of the joint. It is important not to get too worried about calling this arthritis as any problem with a joint can be termed arthritis.
This form of arthritis does not affect other joints unless there is wear and tear in the other joint as well.

Lifestyle

The first line of treatment is to look at your lifestyle. In general exercise is good for your joints. You should have your muscles in peak condition for your age. You can see your physio to discuss an exercise programme that is specific for you. It is wrong to believe that avoiding exercise will help. Of course you will have to be sensible and if an activity is particularly painful then this should be avoided. You should try to substitute another activity to stay fit.

Extra weight is a burden on your joints and perhaps a reduction in your weight should be considered. What specific foods you eat do not affect your joints and there are no specific foods that are good or bad. In general the fitter and stronger you are the less pain you will have from your arthritis even though the actual wear does not change.

Medication

You may be prescribed anti-inflammatory drugs. These can be used for short term periods. They can reduce swelling but mainly act as painkillers. They do not really affect the course of the disease. Paracetamol is a pain killer and is not classified as an anti-inflammatory drug. It is the first drug that should be used for pain. It can be used regularly and has relatively few side effects.

It is uncertain if Glucosamine actually improves the cartilage in osteoarthritis. It seems to improve pain. It is considered a supplement rather than a drug. The American Academy of Orthopaedic surgeons recommends that glucosamine and/or chondroitin sulfate or hydrochloride not be prescribed for patients with symptomatic osteoarthritis of the knee.
This recommendation was based on a report from the Agency for Healthcare Research and Quality. The report was based on one random controlled trial and six systematic reviews on the use of chondroitin sulfate, and/or glucosamine, or hydrochloride among patients with osteoarthritis of the knee.
The random controlled trial found that glucosamine and/or chondroitin did not have any clinical benefit, though five of the six systematic reviews concluded that glucosamine and/or chondroitin are superior to placebo.
Since the Random Controlled Trial is stronger science than the systematic reviews, the AAOS based their decision on the one study.

Surgery

If the wear is not advanced then an arthroscopy can be useful. It is difficult to predict the outcome in the arthritic knee. Some people do very well. In general an arthroscopy gives temporary relief. An arthroscopy is particularly good for catching and locking symptoms.

If the wear is more severe a total knee replacement is the best treatment. It is a very good operation for pain and function is very good also. 1 in 20 patients will have a problem with a knee replacement. This may be infection or loosening. The knee replacement can last up to 15 years. It will wear more quickly with more use and then it can be replaced. It may not be as easy to replace the knee for the 2nd time.

Apart from the knee replacement there are other operations that may be suitable for you. Not every knee is suitable and the operations are in themselves as big as a knee replacement. You can discuss this with your surgeon.