Everything you need to know about the menisci: tears, treatments and their function

What are they?

The menisci are crescent-shaped fibrocartilaginous structures found in line with the medial and lateral tibiofemoral joint. There are two on each knee: the lateral meniscus is positioned on the outer or lateral region of the knee joint, while the medial meniscus is found on the inner or medial region.

What is their function?

One of their most important functions is to provide stability to the knee joint and increase the contact area between the convex articular surface of the femur and the tibia, which is concave on the medial side and convex on the lateral. Additionally, they serve to distribute contact forces between the two bones and are crucial for shock absorption and lubrication. Furthermore, they provide joint proprioception, which is the ability of our brain to perceive the position and movement of our body.

How does one tear their meniscus?

Meniscus tears are common in sports, especially in football, basketball, rugby and skiing, mainly due to the following actions:

  • A sudden turn or change of direction by pivot.
  • Deep squatting or forced bending of the knee.
  • Landing incorrectly after a jump.
  • Although it’s not as common, a meniscus may also be torn as a result of a direct blow to the knee.

However, tears may also occur from activities that have nothing to do with sport and are part of our daily routine. Age is an important factor, because as we age the likelihood of suffering such injuries increases. This is because the collagen component of the menisci gradually loses its elasticity, making them more susceptible to possible tearing.

In older people, what we call “degenerative tears” often appear. These develop after repetitive minor stresses weaken a previously worn meniscus, or can be caused by general wear and tear over time.

How common are meniscus tears?

They are one of the most common knee injuries, causing discomfort and functional limitation in patients. Meniscus repair surgery is the most common surgical procedure in sports medicine.

What are the symptoms of a meniscus tear?

Whether a meniscus tear is caused by high-energy or low-energy movement, patients often feel pain. Over the following days, in addition to the pain, the patient may notice one or more of these symptoms:

  • A swollen joint.
  • Difficulty bending the knee.
  • Difficulty walking.
  • The feeling of the knee locking or catching, and not being able to extend it completely.

Can you operate on all meniscus tears?

Not at all. All tears are different and not all should be operated on, so cases should be considered on an individual basis. Treatment is decided according to the
severity of the symptoms and how much they affect the patient’s day-to-day living. MRI scans are used to observe and analyse the characteristics of the meniscus tear, which is instrumental for diagnosis and treatment.

Like with all kinds of injuries, conservative treatment—i.e. nonsurgical treatment—should be considered first. Such treatment involves anti-inflammatory medication and rehabilitation, and is mainly for those patients whose pain is infrequent and does not significantly affect their daily activities.

In cases where more conservative treatment does not work, or where the pain and functional limitation affects the patient’s quality of life, arthroscopic (keyhole) surgery is required. This procedure will be performed according to the type of fracture, expected level of future physical activity and the needs of each patient.

What surgical treatments are available?

In cases where surgery is required, there are different options available depending on each case, which are set forth below.

Meniscectomy: This is the partial or total resection of the damaged meniscus tissue until a stable meniscus remains. The aim of this procedure is always to conserve the maximum amount of meniscus tissue possible, due to the benefits this brings to the state of the knee in both the short and long term.

Suturing the tear (repair): The tear will be stitched up whenever possible, which will depend on certain factors such as age, location of the tear and when the tear took place. Before surgery, the doctor will consider the possibility of a longer rehabilitation period than is the case with a meniscectomy, and discuss this with the patient.

Suturing techniques will vary depending on the condition and location of the tear.

Meniscus replacement: After performing a partial meniscectomy, pain may gradually appear in the area where a part of the meniscus was removed. This is
called “post-meniscectomy syndrome”. According to the general condition of the joint and the remaining meniscus, the meniscus can be completely replaced in order to reduce pain.

Meniscus transplant: This is the alternative treatment for “post-meniscectomy syndrome”, undertaken in cases where the patient has undergone a total meniscectomy. This procedure replaces the meniscus with a meniscal allograft from a tissue bank.

Do all surgical procedures have the same rehabilitation process?

Rehabilitation processes for meniscus surgery always depend on the surgical procedure performed. However, there is an initial stage (approximately two weeks) that remains the same for all types of operation, in which the goal is to minimise pain and inflammation:

  • Ice the affected area for 10 to 15 minutes every three hours.
  • Take painkillers and anti-inflammatory drugs, as indicated at discharge.
  • Elevate the limb.
  • Perform isometric exercises to activate the quadriceps.

After this initial stage, a second stage of rehabilitation begins. This is particular to each type of surgery, as explained below.

Partial meniscectomy

  • Practise progressive partial weight-bearing exercises with crutches.
  • Perform knee flexion exercises.

Tear suture

  • Until the third week, practise proprioceptive weight-bearing exercises (putting minimum weight on the healthy leg) with crutches and a knee extension splint. From the third to the sixth week, practise partial progressive weight-bearing exercises with crutches, but without the splint.
  • Then practise full extension exercises with a splint until the stitches are removed (after 10 to 15 days), having bent the knee 0-60º until the third week and 0-90º until the sixth week.

Meniscus replacement or transplant

  • You will receive a full discharge and be given crutches and a knee extension splint to keep until the third week. After three weeks have passed, begin to practise progressive weight-bearing exercises with crutches and no splint until the sixth week.
  • Then practise full extension exercises with a splint until the stitches are removed (after 10 to 15 days), having bent the knee 0-60º until the third week and 0-90º until the sixth week.