Published May 21, 2009 06:56PM
Written by: Dr Jordan Metzl, M.D.
Unfortunately, a torn meniscus is a fairly common injury among triathletes, but it doesn’t always have to mean surgery. Dr. Jordan Metzl explains.
John is a 40-year-old triathlete who came in to see me with a painful knee and an MRI scan. “Doc”, he said, “my knee has been hurting for a few weeks, so I got an MRI from my primary care physician. I looked at the report, and it says I have a torn meniscus. Do I need surgery?”
John’s story is a common one in my office and in sports medicine offices around the country. With the advent of MRI (magnetic resonance imaging), doctors can actually look inside the bodies of their patients without making a single incision. In many fields of medicine, this has literally changed the way specialties are practiced. Diseases such as multiple sclerosis or brain cancer are now diagnosed by MRI at earlier stages of progression, resulting in better treatment for patients.
John’s case, however, is another side of the story. Sometimes MRI shows information that doesn’t correlate with a patient’s clinical symptoms. Several studies published in the past six years have looked at the incidence of meniscus tears in normal, asymptomatic knees. Surprisingly, the incidence is about 30 percent to 40 percent of knees, without pain, have a torn meniscus (cartilage) inside. Similar studies have been performed in which the MRI’s of volunteers with no back pain, showed that roughly 40 percent to 50 percent of people over age 50 have a herniated disc on the MRI. These findings on MRI are in the absence of any clinical findings such as knee pain or back pain, and as such, are considered “normal variants.”
MRI is very sensitive, meaning it shows almost every anatomical finding. However, it is not always specific to the actual problem. This means that there are many false positives with MRI. Things show up on MRI that are completely unrelated to the problem, and this can sometimes lead to unnecessary procedures tailored to the MRI rather than the patient’s complaint.
For example, John has a painful knee, but when I ask him about his pain, he says, “Doc, my knee hurts just beneath the knee cap, especially when I bend it.” When I examine his knee, all of the pain is on the undersurface of his patella (kneecap). He feels no pain when I bend his knee and no pain in the inside part of his knee where the meniscus resides. In summary, John has patellofemoral pain, which is a common problem of irritation of the cartilage underneath the patella that happens when the muscles around the knee and hip aren’t strong enough. (For more information, see the article about patellofemoral pain in the November 2005 issue of Triathlete.)
I sent John to physical therapy, he picked up a pair of orthotics at the local running store and within two weeks his knee pain was gone. Yes, he had a torn meniscus on his MRI, but the pain in his knee wasn’t related to the torn meniscus.
The point here is essential: MRI findings are only as good as the patient history and physical examination that accompany them.
As a patient, make sure you are comfortable with how your doctor has explained the problem. Have you tried physical therapy? And most importantly, do you feel comfortable with what you have been told? Getting a second opinion can help as well. If a meniscus tear requires surgery, there will be pain, swelling and clicking in the knee. The patients that receive this treatment are very grateful for it, but the point here is that not all meniscus tears need surgery.
In today’s age of modern medicine, with amazing tools such as MRI at our disposal, making sure that we still listen to what our patients are saying is a challenge for doctors. As patients, you can help us by asking the right questions.
Jordan Metzl, MD, is a nationally recognized sports medicine physician at Hospital for Special Surgery in New York City. In addition to his medical practice, Dr. Metzl is a 26-time marathon runner and six-time Ironman finisher. For more information, visit Drjordanmetzl.com.