Osteoarthritis (OA) of the knee is a chronic, progressive disease of the joint involving the breakdown of cartilage. It is one of the most common diseases affecting virtually everyone over the age of 70. About 20 million Americans have osteoarthritis serious enough to cause pain and limit activities of daily living.

OA is often the result of years of accumulated wear and tear on the joint. There are other factors that play a role in the development of OA including certain occupations (those that involve standing or working on hard surfaces, work that involves impact loading on the knees, etc.), obesity, abnormal joint alignment, sports injuries, and family history.

The process of OA development is fairly straightforward. Cartilage is the smooth gristle that covers the ends of long bones. It is responsible for both absorbing the shock to the joint as well as allowing normal range of motion.

With OA, the smooth cartilage becomes pitted and frayed. Cartilage becomes less elastic, less able to absorb impact, and more easily damaged by overuse or injury. Synovial fluid, which is the joint fluid produced in the normal joint by the cells that line the joint, loses its cushioning and lubricating properties.

Large areas of cartilage can wear away so bones scrape over each other and cause pain.

Cartilage breakdown may cause the joint to lose its normal shape. Bone ends thicken and form bony spurs where the ligaments and joint lining attach to the bone.

Bits of cartilage, called joint mice, float around in the joint space causing further damage and pain.

So what are the treatment options?

OA is not curable yet but it is manageable. It is possible to treat OA so there is less stiffness and pain.

Key treatments include weight loss (if indicated), physical therapy, and anti-inflammatory medications. Occasionally steroid injections or injections of viscosupplements (lubricants) into the knee are helpful.

Ice (cold packs) and quadriceps strengthening exercises are also important in reducing pain.

Arthroscopy, a procedure where a small telescope is inserted into the knee and damaged or diseased tissue is removed, may be helpful in certain cases.

Bracing of the knee to help unload the narrowed compartment of the knee are very useful. These braces actually open up the narrowed compartment and ensure that a patient can walk with less pain. Coupled with arthroscopy and viscosupplementation, they may be extremely useful for relieving symptoms.

Wedge insoles in the shoes may help by partially correcting the alignment problem in the knees.

Finally in patients where all conservative measures have been exhausted, surgical correction in the form of total knee replacement may be required.