I have said repeatedly that surgery to trim attached cartilage in the knee is usually worthless. I have seen many patients who have had cartilage removed by surgeons for an average charge of $5000, and then they must have a knee replacement several years later. The surgeons must know about the harm they are doing because they have to see the patients for follow-up. The American Academy of Orthopedic Surgeons does not recommend routine arthroscopic treatment for patients with arthritis, yet more than two million arthroscopic procedures are performed world-wide each year, at a cost in the United States of more than $3 billion per year.
In arthroscopic knee surgery, physicians make several small incisions around the joint and insert a tiny camera that allows them to see inside the knee as well as to insert small instruments to correct problems they identify. Often the surgery is performed to remove part of a damaged meniscus, a disc of cartilage that helps cushion the knee. Meniscal tears are common and are unlikely to be the cause of knee pain, aching or stiffness.
The knee is just bones held together by four bands called ligaments. Bones are soft, so the ends of bones are covered with a hard gristle called cartilage. Cartilage serves as padding to protect the ends of the bones. Once cartilage is broken, it can never heal. When you break a small amount of cartilage in your knee, your knee cartilage can never again fit together properly, and when you put force on the knee, you break off more cartilage. When surgeons remove cartilage, they leave less cartilage than you had before the surgery. Eventually the knee joint runs out of cartilage and when bone rubs on bone, it hurts all the time and a person must have a knee replacement just to be able to sleep at night. Surgery to “smooth” or remove cartilage just hastens knee replacement.
Helpful Knee Surgeries
Some people have knee pain caused by loose pieces of cartilage. If you have sudden locking of the knee when you walk or you cannot fully straighten or bend your knee, you may be helped by surgery to remove the loose piece that is blocking the movement of the joint. If your injury is caused by a torn ligament, doctors can also repair or replace the ligament, which can stabilize the knee joint. However, if your ligaments are not injured and you do not have loose pieces of cartilage, arthroscopic surgery is not likely to help you.
Almost 20 years ago, the headline from Baylor Medical School was “Study Finds Common Knee Surgery No Better Than Placebo” (NEJM, July 11, 2002;347:81-88). Patients with osteoarthritis of the knee who underwent placebo arthroscopic surgery were just as likely to report pain relief as those who received the real procedure. The researchers said that their results challenge the usefulness of one of the most common surgical procedures performed for osteoarthritis of the knee.
In the study, 180 patients with knee pain were randomized into three groups. One group received debridement, in which worn, torn, or loose cartilage was cut away and removed with the aid of an arthroscope. The second group underwent arthroscopic lavage, in which loose cartilage was flushed out. The third group underwent simulated arthroscopic surgery; small incisions were made, but no instruments were inserted and no cartilage removed.
The people who did not have surgery on their cartilage did better than the people who had some of their cartilage removed. Lead investigator Dr. Elda P. Way stated, “The fact that the effectiveness of arthroscopic lavage or debridement in patients with osteoarthritis of the knee is no greater than that of placebo surgery makes us question whether the one billion plus dollars spent on these procedures might not be put to better use.”
A review of 13 studies involving nearly 1,700 patients found that arthroscopic surgery did not provide lasting pain relief or improve function for most of the patients (BMJ, May 10, 2017). Those studies compared the surgery with a variety of options, including physical therapy, exercise and even placebo surgery. Less than 15 percent of patients felt an improvement in pain and function three months after the procedure, and that those effects disappeared after one year, the review found. In addition, the surgery exposed patients to possible knee infections.
Researchers in Denmark showed that arthroscopic repair of the meniscus for middle-aged people was not much better than exercise in relieving pain and carried a risk of rare but debilitating side effects (BMJ, June 16, 2015;350:h2747). Another study of 156 patients in the US Military Health system showed that knee pain is treated more effectively by physical therapy than steroid injections into the knee (JAMA, June 23, 2020;323(24):2453).
Based on these many studies and my own observations, I recommend that you do not get knee surgery unless you have a torn ligament that needs to be repaired or you have sudden locking of the knee during walking or you cannot fully straighten or bend you knee. Otherwise, surgery is likely to hasten your need for another surgery, knee replacement.