Many thousands of patients with painful osteoarthritis of the knees are treated each year in the U.S. by arthroscopic surgery, a minimally invasive procedure where surgical instruments are inserted into the knee joint through small incisions.

To carry out arthroscopic surgery on the knee, orthopedic surgeons make 2 or 3 small incisions, insert a small, fiber-optic arthroscopic device, inflate the knee with fluid under pressure to better visualize the joint, and then wash out loose fragments or repair tears in the meniscus (cartilages within the knee that absorb weight and stabilize the joint).

But several years ago, the Veterans Administration carried out a startling study that compared the outcomes of individuals who either had one of these arthroscopic procedures or underwent a sham operation (i.e., one where the surgical incisions were made in the knee but then the rest of the operation was not done).

Quite surprisingly, these two groups did equally well during follow-up, whether they had the full operation or the sham procedure.

Now, 2 recent articles in the New England Journal of Medicine have come up with similar conclusions about the lack of value of arthroscopic surgery for osteoporosis of the knee: After two years of follow-up in a controlled trial, patients who underwent arthroscopic surgery for knee osteoarthritis had no greater relief of pain or mobility than those who were treated medically. These medical treatments included weight loss when necessary, physical therapy, exercise, education, glucosamine sulfate capsules, pain medication with acetaminophen (Tylenol®) or nonsteroidal anti-inflammatory drugs, and injections of hyaluronic acid into the joint.

Acute tears in a meniscus are common athletic injuries that often require surgical treatment. However, many older individuals with knee osteoarthritis have small meniscus tears that usually do not contribute to pain or loss of mobility, and therefore do not need surgical repair.

Although the results of the latest studies have received much media attention, readers should not harbor the idea that surgery on the knees in people with osteoarthritis is never a good idea. This is because the sudden onset of pain and limited mobility may indicate a severe meniscus tear that will remain painful unless repaired by surgery.

In addition, some people suffer chronic pain that is not relieved by medical treatment because their knee cartilages have worn out completely and the bones in the knee joint are rubbing against one another. These patients can unquestionably experience improvement with a total knee replacement.

A word about knee replacements: For many years, doctors concerned that an artificial knee would not last very long told these patients to live with the pain as long as possible before getting a total knee replacement. In general, women have tended to wait longer than men before having their bum knees replaced. Now, however, this advice is out of date because improvements in artificial joint technology and surgical techniques have made the implanted joints more likely to survive longer.

All this means that, nowadays, people with severe knee joint pain and who are markedly limited when they try to carry out daily activities should consider joint replacement sooner rather than later. Older people who wait too long may develop other limiting medical problems or suffer knee deformities that make surgery more difficult.