I am 55 years old with osteoarthritis of the right knee. No treatments have given me much relief. I have heard of a new treatment involving hyaluronic acid, which is available in Europe. What do you think of this treatment?

Hyaluronic acid is a natural component of cartilage and joint fluid. It helps to maintain the structure of the cartilage tissue and also serves as a lubricant in joints. Studies indicate it suppresses joint inflammation. Recently, hyaluronic acid injections have been approved in this country. The use of hyaluronic acid first was used in veterinary medicine to treat osteoarthritis in dogs and horses. The use in humans has been extensively studied in Europe with reported improvements in overall condition in patients. Clinical trials in the United States showed that some patients experienced pain relief one week after the third injection of hyaluronic acid; for others, it was after the fifth. Pain relief often lasted for six months.