Osteoarthritis (OA) is the most common form of arthritis, affecting anywhere from 30 to 50 million Americans. It is a disease that is due to disordered metabolism in cartilage, the gristle that caps the ends of long bones within a joint. The disordered metabolism leads to a cycle of cartilage deterioration accompanied by inflammation within the joint capsule leading to more deterioration of cartilage.

The primary symptoms associated with OA are pain, stiffness, and swelling.

Unlike rheumatoid arthritis, osteoarthritis is a disease for which there are no revolutionary biologic therapies that are available to put it into remission. No treatments prevent osteoarthritis or reverse or block the disease process once it begins.

Current treatments relieve only the symptoms. Researchers are looking for drugs that can prevent, slow down, or reverse joint damage. One antibiotic drug, doxycycline, may stop certain enzymes from damaging cartilage. The drug has had mixed reviews in clinical trials, but more studies are needed.

Researchers are also studying growth factors or other natural chemical messengers. These potential medicines may be able to stimulate cartilage growth or repair.

Acupuncture has received a lot of press recently. In acupuncture, fine needles are inserted into the skin at various points on the body.

Scientists think that the needles stimulate the release of natural, pain-relieving chemicals produced by the brain or the nervous system. Findings suggest that traditional Chinese acupuncture is effective in some patients as an additional therapy for osteoarthritis, reducing pain and improving function. Still? acupuncture is a symptomatic therapy and is not designed to reverse or slow down cartilage loss.

Anesthetic patches containing lidocaine are currently being studied as an adjunctive treatment for the pain of OA. Preliminary studies look promising.

Nutritional supplements are often reported as helpful in treating osteoarthritis.

Glucosamine and chondroitin sulfate are components of normal cartilage. Scientific studies on these two nutritional supplements have come up with conflicting conclusions. Most European studies have demonstrated that this combination of nutritional supplements is effective not only for pain relief but also apparently slows down the rate of cartilage deterioration. However, a recent clinical trial conducted by The National Center for Complementary and Alternative Medicine at NIH failed to demonstrate any benefit in patients with mild OA but did appear to show that there was some possible benefit for patients with moderate OA.

There is interest in the role of vitamins for OA. Apparently, progression of the disease appears to be less in patients with high levels of vitamin D or C intake. More studies are needed to confirm these reports.

Injecting hyaluronic acid into the knee joint provides long-term pain relief for some people with osteoarthritis. Hyaluronic acid is a natural component of cartilage and joint fluid. It lubricates and absorbs shock in the joint. The Food and Drug Administration (FDA) has approved a number of these types of preparations (also called viscosupplements) for patients with osteoarthritis of the knee if they do not get relief from exercise, physical therapy, or simple analgesics. Researchers are studying whether hyaluronic acid can slow down the progression of osteoarthritis.

Tissue Engineering is a technology that involves removing cells from the body and replacing them to improve certain body functions. There are three major types of tissue engineering for use in treating osteoarthritis.

? Enzyme engineering. Certain body chemicals called enzymes may help cartilage to break down. Scientists are working to genetically engineer cells that would inhibit these enzymes and prevent the damage they cause. Cells are removed from the body, genetically changed, and then injected back into the affected joint. They protect the joint from damaging enzymes.

? Cartilage cell replacement. Researchers remove cartilage cells from the patient's own joint, clone or grow new cells using tissue culture and other laboratory techniques, and inject the newly grown cells into the patient's joint. The cells are kept in place with a biodegradable mesh. Patients with cartilage cell replacement have decreased osteoarthritis symptoms. Actual cartilage repair is limited, however. The procedure is also arduous in that the patient must go at limited weight-bearing for six months.

? Stem cell transplantation. Stem cells are primitive cells that can transform into other kinds of cells, such as muscle or bone cells. They are usually taken from bone marrow. Researchers are able to insert stem cells into cartilage where they make new cartilage. If successful, this process could be used to repair damaged cartilage and avoid the need for surgical joint replacements with metal or plastics.

? Platelet rich plasma grafting techniques are attracting interest. The patient has 20 cc's of blood drawn and the blood is spun down in a centrifuge. The layer containing platelets (a type of blood cell) is selectively removed. The cartilage in the joint is then ?teased? to bleed using a special needle. Stem cells may be inserted and then the platelet rich plasma, which contains an abundant amount of growth factors is added. Cartilage cells are stimulated to grow. The attraction of this approach is that the procedure is not nearly as invasive as cartilage cell transplantation and the patient does not have to go at extreme limited weight-bearing.