The shape of a meniscus tear is also important in determining whether it can heal on its own, be treated surgically, or cannot be fixed. Although there are many shapes and sizes of meniscus tear, the three main shapes are longitudinal, radial, and horizontal.
- Longitudinal meniscus tear, also called a circumferential tear, runs along the length of the meniscus but does not go all the way through it. It usually starts as a partial tear at the back of the meniscus and heals on its own. A longitudinal meniscus tear that does not heal properly, however, can lead to a displaced bucket handle tear, which does go all the way through the meniscus. A bucket handle tear makes up 10 percent of all meniscus tears and cause the knee to lock. Young athletes most often experience a bucket handle tear, and it occurs along with 50 percent of ACL injuries.
- Radial split meniscus tear begins along the inner edge of the meniscus and runs part or all the way through it. This type of tear frequently occurs in the lateral meniscus. When a radial split meniscus tear is small it is difficult to see, but when it grows and becomes a complete tear, it is then called a parrot’s beak tear and looks like a piece of the meniscus is missing. An oblique tear is perhaps the most common type of meniscus tear.Over time, this tear will grow larger and catch or lock more often. A parrot’s beak tear is caused by trauma or forceful, repetitive stress activities and is often seen along with other injuries.
- Horizontal meniscus tear, also known as a cleavage tear, begins as a horizontal split deep in the meniscus which then slices the meniscus into a top and bottom section. This type of tear is rare, but when it occurs it is usually the result of a minor injury associated with knee rotation or degeneration. If not treated, a horizontal meniscus tear can develop into a horizontal flap tear, which results from a strong force that tears the meniscus from the inner rim. Meniscal cysts are sometimes associated with a horizontal flap tear.
Complex tears are a combination of these shapes. Once a doctor has determined the type of tear you have, he or she can decide which treatment course to take.