I have recently had an increase in the number of patients I am treating for knee pain who were informed by their physician that the cause of that pain is a meniscal tear and that surgery is necessary. How was this diagnosis achieved? The MRI. In most cases, the patients told me that no clinical evaluation was performed. They simply told the physician where they had pain and a prescription was provided to obtain an MRI. The MRI indicated that a meniscal tear was present, and there you have it. If the MRI says a meniscal tear is present then that must be causing the knee pain, right? Wrong.
Let's stop a second and look at that MRI finding. The MRI never identified whether the meniscal tear was acute or chronic. It never described the magnitude of the tear. It never correlated the timing of the pain experienced to the time frame when the meniscal tear occurred. It never ruled out that the mensical tear had healed on its own and that another tissue was irritated creating pain at the knee. This is why I constantly profess that the MRI should not be the only mechanism for identifying the cause of pain; a complete clinical evaluation should be.
There was a study performed to test the correlation between meniscal tears and knee pain. Two groups were studied; one group had knee pain and the other had no knee pain. The group with knee pain was found to have meniscal tears 63 percent of the time. In the group with absolutely no knee pain, 60 percent were found to have meniscal tears. This study proved that there is little correlation between mensical tears and knee pain. What it did prove is that roughly 60 percent of the population ended up having a meniscal tear. These types of tears are degenerative and the body healed them. This is why the tears created no pain. I would estimate that the group who had knee pain, had pain due to another tissue creating the pain signal at the knee. If you had taken an MRI of their knee the day before they had knee pain, you would have found that very meniscal tear.
Now let's look at the mechanisms for creating an acute tear of a meniscus. You have to excessively straighten the knee, excessively flex the knee or weight bear on the knee, and rotate the leg excessively to tear the meniscus. Walking up a flight of stairs, bending and kneeling on your knee or weight bearing awkwardly on your leg does not qualify as mechanisms for tearing a meniscus. The meniscus is made of fibrocartilage and not marshmallow. It is a tough material not easily torn. The majority of patients I treat for a supposed mensical tear can not recall a specific incident that created their knee pain. With this in mind, there is a good chance that the meniscal tear found on the MRI is just a degenerative tear unrelated to the knee pain.
The True Cause
I have found that in almost every case someone was told the cause of their pain was a meniscus tear, the cause of their pain was a hamstring strain. The hamstrings are the muscle in the back of the thigh. The tendons wrap around on either side of the knee. If an awkward movement occurs or excessive force is placed on the knee, there is a good chance that the tissue most affected is the hamstring muscle/tendon combination. Often times the patient will describe a "popping" sensation at the time of the strain. In this case, full range of motion is found at the joint. If muscle testing is performed, resistive knee bending is weak and painful at the knee. If you touch the hamstring's associated tendons, pain is experienced at these tissues and not at the joint line of the knee. Resolution of the associated knee pain is achieved by strengthening the supporting muscles of the knee including the quads, hamstrings and calf muscles.
The next time a diagnosis is achieved primarily through an MRI, think twice about getting surgery or taking a cortisone shot. There is good chance the MRI result is inconclusive and the treatments provided will not address the true cause of your pain. Look at the clinical results for the true cause of pain.
