Arthroscopy to treat arthritis in the knee is one of the most common surgical procedures performed in the United States. However, according to a group of researchers, the procedure is both unnecessary and ineffective in treating the condition.

A study involving 178 men and women found that of 92 participants assigned to receive surgery, the 86 who actually underwent the surgery fared no better than the 86 who received only medications for inflammation along with physical therapy. The average age of participants was 60, which is the typical age for this type of arthritis patient. The study is published in the New England Journal of Medicine.

The results of this study reflect the findings of another study published in 2002 by the Department of Veterans Affairs in which participants were assigned either to real surgery or a fake operation. The results showed that real surgery offered no greater benefits than the fake. Experts disagree as to the effects of the two studies with some insisting that the new study only confirms what was already known, while others anticipate that doctors who did not hold the 2002 study results as true will now cease to perform the surgical procedure.

Dr. Brian G. Feagan, head of the clinical trials unit at the Fowler Kennedy Sport Medicine Clinic in London, Ontario, and an author of the new study said, “I think we have definitive evidence that that procedure is ineffective.” He also added, “If it isn’t effective, patients should not be undergoing it.”

These surgeries cost about $5,000 and are performed on hundreds of thousands of Americans each year. In 2003, Medicare halted payment for the procedure done for severe arthritis of the knee, causing the number of claims for the procedure to drop dramatically. However, doctors can be reimbursed for the procedure by modifying the patient’s diagnosis making it unclear as to whether the majority of doctors have stopped performing the procedure.

Feagan said that as many as 33 percent of the estimated 950,000 arthroscopic knee surgeries performed annually in the United States are most likely still being done for arthritis, which affects about 27 million Americans. During the surgical procedure small incisions are created in the knee, and an arthroscope is inserted so that the joint may be seen. Debris is then flushed from the knee or rough areas of cartilage are shaved, and the joint is cleansed. It seems logical that debris and rough areas could play a role in increased knee pain, giving many doctors pause in coming to believe the procedure is of no benefit to the patient as deemed by the results of the 2002 study.

According to Dr. Bruce Moseley, of the Richmond Bone and Joint Clinic in Texas, and the 2002 study’s lead investigator, “What happened after our study was that organized orthopedics rallied the troops to try and discredit our study as much as possible.” He said that, “People continued to practice the way they practiced.” Many said the 2002 study was flawed because all the surgeries were performed by only one surgeon, with all the subjects being men, who were older than the typical arthritis patient.

Feagan, along with other experts, stress that the surgery can help people who have problems other than arthritis, such as a badly torn ligament or cartilage. The hope is that the new research will encourage surgeons to be more selective in offering the procedure and that patients will consider their options more stringently before demanding it.

In yet another study published in The Journal, it was found that even when an M.R.I. scan shows damaged cartilage in an arthritis patient’s knee, that knee pain might not be associated with the injury. In the study of 991 middle aged and elderly people, sixty-three percent of participants with knee pain from arthritis had a torn or destroyed meniscus, which is the wedge-shaped piece of cartilage that helps to stabilize the knee. However, 60 percent of those with arthritis but without knee pain also had a damaged meniscus.

The study’s lead author, Dr. Martin Englund of Boston University stated, “In patients with arthritis, almost everybody has meniscal tears. We are so drilled to think, ‘Oh, a meniscal tear — that must be painful,’ or ‘That’s the cause of the pain.’ But it may be involved in the disease process itself. There are many, many other reasons for pain in knee, but the meniscus is the structure we focus on and see.”