A knee meniscus tear is one of the common causes of knee pain. The meniscus is basically the shock absorber within the knee. You can tear either medial (inside) or lateral (outside) meniscus. The inside meniscus is the more commonly injured one.
What Causes a Knee Meniscus Tear?
There are two general ways in which the meniscus becomes torn. There can be an acute injury such as a twisting injury or a sports injury where you didn’t have pain, but you did something such as getting hit, you twisted and turned and all of a sudden there is you have this painful reaction because you tore your meniscus. Or – and this is more common in folks as they get a little on in life in their 50s, 60s, 70s, 80s and beyond – there can be more of a degenerative tear within the meniscus, where there is no frank tear but over time it has started to tear somewhat.
Knee Meniscus Tear Diagnosis
Meniscus pain, depending on which meniscus you tear will either be on the inside of the knee, the outside, or the entire knee. The diagnosis of a meniscus tear begins with a history and physical examination. During the history, it will be important to ask about the onset of injury, the mechanism of the onset of injury, where the pain is, what kind of pain it is, when the pain is worst, and what kinds of things make the pain better.
On physical exam, often the joint line will be quite tender with a meniscus tear. There are certain provocative maneuvers like McMurray’s and Apley’s that the physician will do in order to elicit pain that more generally comes from a meniscus. Although these physical exam maneuvers tend to be relatively sensitive, meaning that if you have a meniscus, they tend to be positive, they are relatively non-specific, which means that people who don’t have a meniscus tear may also have a positive response to these provocative maneuvers. So those tests certainly lead you down the road toward the diagnosis although they are not necessarily definitive for the diagnosis.
Sometimes when a meniscus tear is suspected, an MRI will be ordered, and on an MRI you can see a meniscus tear. A meniscus tear can be there and not necessarily be causing the pain. So you take all of the imaging studies with a grain of salt and put it into the context of the entire picture.