What is a meniscus injury? What are the types?

In life, we should pay more attention to protecting ourselves and try to avoid injuries. However, sometimes some accidents are unavoidable. Some people may suffer meniscus injuries due to sports and other reasons. When they hear from the doctor that they have meniscus injuries, many patients are actually confused because they do not understand what meniscus injuries are. Let's take a look at it together.

What is the meniscus?

The menisci are two crescent-shaped fibrous cartilages located on the medial and lateral articular surfaces of the tibial plateau. Its cross-section is triangular, thick on the outside and thin on the inside, slightly concave on the top to fit with the femoral condyle, and flat on the bottom to connect with the tibial plateau. This structure just makes the femoral condyle form a deeper depression on the tibial plateau, thereby increasing the stability of the spherical femoral condyle and tibial plateau. The anterior and posterior ends of the meniscus are attached to the non-articular surface of the middle part of the tibial plateau, in front and behind the intercondylar spine. This area is also called the anterior and posterior horn of the meniscus.

Types of meniscus injuries

I believe many people have heard of meniscus injury. Do you know what types of meniscus injuries there are? If you don’t know, let’s take a look at them below.

1. Borderline

The rupture is located at the front, middle and back positions of the edge of the medial meniscus. Severe edge-type rupture is a complete rupture of the perimeter, connected only by the front and back corners, and the ruptured waist slides toward the center of the knee. This can lead to locking of the joint. Symptoms are most pronounced when the knee is extended. It is believed that this type has the potential to heal on its own. Some patients were healed by suture.

2. Front angle type

The rupture is located at the front corner and may be just a crack, or the ruptured part may roll back and thicken, or the front corner connecting part may be broken. The pain is located in front of the knee, but the patient may not be able to distinguish between the inner and outer sides.

3. Rear angle type

The rupture is located at the posterior corner and may appear as a crack. The cleft is curled up and the connecting fibers of the posterior horn are broken. The pain is obvious when the knee is excessively flexed. The pain can usually be located on the posterior medial side, but in some cases the side cannot be determined.

4. Horizontal

This type of rupture occurs when the medial side of the meniscus is split transversely, and the location, number and depth of the rupture are different.

Transverse cleavage of the medial meniscus

5. Bucket handle type

The medial meniscus is ruptured longitudinally. The cracks may vary in size and may also be transverse. The rupture was obviously thickened and the synovial membrane of the femoral condyle was extensively damaged. The affected knee often "locks", making walking difficult and time-consuming.

6. Inner edge type

There is one or more injuries on the inner edge of the meniscus, which may appear as comminuted damage, with occasional free fragments entering the joint cavity. This type of disease often affects the extension and flexion of the knee, manifesting as long-term pain, obvious damage to the femoral condyle articular surface, and sometimes joint locking. Plain X-rays are occasionally seen. Free bone fragments.

7. Horizontal splitting type

It is caused by strong rotation between the tibiofemoral joint, resulting in horizontal separation between the upper and lower layers of the medial meniscus. If diagnosed early and good braking is achieved, it may be possible to repair the disease. The affected knee may experience dull pain, instability, or a feeling of slipping.

8. Longitudinal fissure type

It is a longitudinal rupture of the medial meniscus. It may also break at the anterior or posterior corner, with the free part entering the knee, becoming the main factor of knee pain and flexion and extension obstruction.

9. Relaxed

The medial meniscus is loose at its attachment to the joint capsule. Every time the knee is flexed, extended, or rotated, there is an unstable, slipping feeling. When the tibiofemoral joint is squeezed toward the center of the knee, the medial joint capsule (and skin) may sink into the joint space. This type may be caused by trauma or congenital structural defects.