Knee injuries

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What is it about ?

The knee joint is the joint that connects the thigh bone (femur) to one of the 2 bones in the leg (tibia).

The leg is made up of 2 bones: the largest, the tibia, and the thinnest, the fibula, also called the fibula.
The kneecap is a small, triangular bone located at the front of the knee joint. The patella is held and suspended in the tendon of the muscle located at the front of the thigh, the quadriceps. It is attached to the tibia by the patellar tendon (or patellar tendon).
The place where the bones form the joint is covered with cartilage.

The femur has 2 rounded ends, so that it can roll over the tibia when bending or stretching the leg. As the top of the tibia is flattened, there are 2 crescent-shaped pieces of cartilage: the menisci which serve to level the joint surfaces. A meniscus is ultra thin on the inside and thicker on the outside. In this way, it forms what looks like a saucer, in which the head of the femur can move without problem. To ensure the stability of the knee, the meniscus is reinforced by different structures:

  • two strong ligaments on the internal and external faces (the medial or internal collateral ligament and the lateral or external collateral ligament);
  • the cruciate ligaments inside the knee;
  • the joint capsule, which envelops the whole;
  • a set of muscles and tendons that allow movement of the knee.

Following a (sports) accident, one or more elements of the knee joint may be damaged. The most common injuries are tears of the medial meniscus, anterior cruciate ligament, and medial collateral ligament. These can be done separately or at the same time. Another common pathology is the dislocation of the kneecap.

How to recognize them?

The main symptoms that accompany a knee injury are pain, swelling, and limitation of movement.

Meniscus injury

The main cause of a meniscus tear is when you rotate your knee when the knee is flexed and your foot is not rotating at the same time. This is the case, for example, when a footballer performs a rotational movement, but his crampons get stuck in the field. The pain is usually bearable with only slight swelling. The swelling indicates the presence of fluid or blood in the joint. The knee can sometimes lock up when you squat. In some cases, the meniscus injury does not cause symptoms at all.

Tear of the anterior cruciate ligament

An anterior cruciate ligament tear is usually the result of a sudden, violent twisting motion of the knee or a sudden “stop” that causes the femur to slide relative to the tibia (often occurs in indoor football or during landing after a jump).
In almost all cases, the knee swells greatly just after the accident and loses a large part of its mobility. It is usually difficult to locate the sore spot and the pain is diffuse. Sometimes pain is felt on the outside of the knee. The knee often feels unstable, as if it is buckling under when you walk or change direction. Healing is slow, lasting between 2 and 6 weeks.

Medial collateral ligament tear

A tear of this ligament is usually the result of a strong impact on the lateral aspect of the knee. The tear is usually created at the level of the superior insertion of the ligament, on the femur. This area is painful, may swell locally and turn blue. Each movement of the tibia outward causes pain. The pain limits the movement of the knee. This reduced mobility can last for several weeks. Palpation of the ligament can even be painful for months.

Patella dislocation

When flexing the knee, the kneecap slides over the femur and moves outward. It spontaneously resumes its place when the knee is stretched. When there is a dislocation, she goes too far outside and can no longer return to her place. The knee has significant swelling and the painful point is difficult to locate (most often on the inside of the kneecap). There is frequently a blue discoloration of the skin on the inside of the knee, near the kneecap.

How is the diagnosis made?

The doctor will ask you questions about the circumstances of the accident:

  • Is it a sporting accident or something else? Was there direct contact (a blow) or is it a sprain?
  • What were the first symptoms? Has there been any swelling? Did you have pain? If so, where? Did the first symptoms appear immediately or some time after the accident? Were you able to continue your activity or did you have to stop immediately?
  • When did you hurt yourself? Are you feeling better or do you still have symptoms?

The doctor will also examine your knee very carefully. He will thus assess the appearance of the knee, its mobility, the menisci, ligaments and the stability of the knee:

  • Appearance: is the knee swollen? Is there fluid or blood in the joint? Is there an external bruise (hematoma)? Is the patella dislocated?
  • Mobility: is knee flexion and extension complete, painful or painless?
  • The menisci and ligaments are tested. Some movements cause pain, some don’t.
  • Knee stability: Were abnormal movements possible after the accident, such as excessive normal mobility or unusual mobility for a normal knee?

In addition, additional examinations are sometimes necessary:

  • A joint puncture: the excess fluid or blood present in the knee is aspirated using a syringe;
  • An ultrasound in case of lesions of the patellar tendon or ligaments;
  • An MRI provides detailed information on the condition of the knee joint and is performed when the doctor considers that surgery is necessary (tear of the meniscus, tear of the cruciate ligaments);
  • An x-ray if a fracture is suspected.

What can you do ?

If you injure your knee in a (sports) accident, you are advised to take some basic steps before you even see a doctor:

  • Rest: stop straining the affected joint until you know what you have;
  • Application of ice: the cold eases the pain and swelling of the joint. Make sure that the cold source does not come into direct contact with the skin to avoid burns. To do this, wrap the ice packs or ice cubes in a towel or washcloth. Apply ice to the affected area intermittently, for example every 10 minutes;
  • Elevation: If the knee is very swollen, elevate it.

Once the diagnosis is made, it is generally a good idea to:

  • Mobilize the knee as much as possible, without leaning on it, as soon as the pain and swelling allow it. An often recommended activity is to pedal against a low resistance;
  • Continue to use your leg muscles as much as possible to prevent them from losing strength too quickly. Be especially careful to work the muscle in the front of your thigh (quadriceps).

In many cases, the knee will heal on its own, with a suitable exercise program. The accompaniment of a physiotherapist can be useful. You can then repeat the exercises he taught you at home.

What can your doctor do?

In the treatment of a knee injury, medication is not necessary except painkillers (paracetamol) and sometimes anti-inflammatory drugs (for example, ibuprofen or naproxen) to decrease swelling. It will inform you of the nature and duration of the recovery process to be expected (depending on the cause). The knee cannot be immobilized without a clear diagnosis.

In the event of a meniscus injury, the doctor will refer you to a specialist for arthroscopy if the tear causes symptoms such as a knee blockage or painful throws during (twisting) movements.

In the case of a tear of the cruciate ligament (anterior), the doctor will start by prescribing you suitable exercises in order to restore the mobility of the knee as much as possible. Usually, this treatment alone is sufficient. Sometimes the cruciate ligaments will be repaired surgically (after about 1 month), especially in cases of marked instability and if, for example, you play a sport that strains your knee. In general, sports activities can be resumed between 4 to 8 months after the accident.

In the case of a dislocated patella that does not spontaneously return to its initial position, the doctor will put it back in place. An operation is only necessary if the problem is repeated very often and causes a lot of inconvenience. However, it may be helpful to wear a knee brace for a few weeks to keep the kneecap in place. Muscle rehabilitation by a physiotherapist can also be useful to prevent a recurrence.

In the event of a medial or lateral collateral ligament injury, the doctor may offer a hinged knee brace. This special knee brace allows you to bend and straighten the knee, but it prevents movement to the sides. As a result, the ligaments are not stressed at all.

The quadriceps strengthening exercises help to regain good mobility and good stability of the knee as quickly as possible.

Until the diagnosis is made with certainty, the doctor will not immobilize the knee. Elastic bandages do not speed healing, but they can ease pain.

Want to know more?

Source

Foreign clinical practice guide ‘Knee trauma’ (2000), updated on 06/26/2017 and adapted to the Belgian context on 03/23/2018 – ebpracticenet