One speaks of a distortion or sprain of the knee joint, when one of the knee ligaments is overstretched and some fibers tear.
Symptoms: pain in the injured knee ligament, swelling, instability, restriction of movement when bending and stretching the knee joint.
Causes: an indirect force acts on the knee, like a sudden twist.
Treatment: immobilization, raising, cooling, taping, exercises. Rarely surgical intervention is necessary.
What is it?
The knee joint has four ligaments. In the middle of the joint are the two cruciate ligaments (anterior and posterior cruciate ligaments, short VKB and HKB).
On the sides are the two collateral ligaments (medial and lateral collateral ligament, MKB and LKB for short, also called inner and outer ligaments). These fiber strands work together to stabilize the knee joint and protect it from injury.
A sprain of the knee means that at least one of the ligaments has been stressed beyond its natural elasticity and some or all of the fibers are damaged. This happens when a force is applied to the joint, such as when twisting the knee in an unfortunate fall or during sports.
Children rarely get a knee sprain.
There are three different types of knee distortion:
- 1st degree – few fibers (less than 10%) are damaged and/or torn, healing usually occurs on their own.
- 2nd degree – many fibers are torn, but the ligament continuity is still given.
- 3rd degree – the ligament is completely torn. In this case, there will be an indication for surgery.
The knee joint is stabilized by four major ligaments: anterior and posterior cruciate ligaments, inner ligaments and outer ligaments. The ligaments have the task of limiting excessive knee movements. The anterior cruciate ligament prevents the shin from shifting too far forward compared to the femur, the posterior cruciate ligament prevents the shin from shifting beyond the natural limit to the back.
The inner lateral ligament prevents excessive lateral spreading of the shin and the outer ligament prevents its exaggerated approach.
A sprained knee becomes unstable on the side of the injured ligament. There are four specific tests to evaluate each individual band.
Causes of knee sprain
A knee distortion can have the following triggers:
- excessive twisting of the knee joint
- Shifting body weight when running or skiing
- unfortunate occurrence after a jump
- trauma to the outer or inner knee area; there is the same probability of a left or right-sided knee sprain
- trauma to the anterior, bent knee while the foot is firmly on the ground
Risk factors for knee sprain
These factors increase the risk of knee sprain:
- Practice of certain sports, such as football, volleyball, skiing, basketball, rarely cycling
- poor coordination
- poor sense of balance
- insufficient flexibility or muscle and ligament weakness
- Sagging of the ligaments
Signs and symptoms of knee sprain
Typical symptoms of a sprained knee include pain, swelling and bruising (hematoma).
With a serious injury, the knee joint may have instability, the patient feels that the knee is giving way.
In the event of an accident, a cracking noise can occur, which could mean a ligament or meniscus injury. Symptoms may appear immediately after the injury or up to two days afterward.
The symptoms can be described as follows:
- The knee hurts.
- Near the knee, swelling, redness, overheating or bruising may be noticeable.
- The range of motion of the knee is limited; the patient also feels pain with passive hyperflexion and hyperextension.
- Loading of the injured leg is not possible; when standing, the leg cannot be fully stretched or bent.
- A feeling of stiffness of the joint.
- Swelling in the knee.
- As a rule, the patient does not have a fever.
The doctor will inquire about the symptoms and the course of injury. The knee must be examined for stability and pain intensity.
The exact location where the pain occurs can provide information about which of the knee ligaments was injured.
If the pain occurs on the inside of the knee, this is an indication of the inner ligament (medial collateral ligament); such an MKB strain is the most common.
Pain on the outside of the knee, on the other hand, indicates an injury to the outer ligament.
The anterior drawer test is performed to assess the anterior cruciate ligament. The patient lies on his back with 90° flexion of the knee, the foot is stabilized on the couch.
The examiner grabs the shin from behind above the calf muscle and pulls it forward with constant force. If the shin can be advanced beyond its normal position (like a drawer), the test is positive. Here a comparison with the healthy knee makes sense, because some people have looser ligaments. In the case of a positive test result, there is an anterior cruciate ligament rupture.
The posterior drawer test is performed to assess the posterior cruciate ligament. The patient lies on his back, the knee is bent at 90° and the foot is stabilized on the couch.
The shin bone is caught at the shinbone bump and pushed backwards with constant force. If it can be shifted beyond its normal position, the test is positive and a sign of a rupture of the posterior cruciate ligament.
XJ reconstruction posterior cruciate ligament
The valgus stress test is used to assess the medial collateral ligament (MKB, inner ligament). In a 30° flexion of the knee joint, the ankle is stabilized and the knee is pushed inwards. If the knee can be pushed further inwards than normal (compared to a healthy leg), the test can be evaluated as positive and indicates an inner ligament rupture.
The varus stress test is performed to determine whether the lateral collateral ligament (MCI) is injured. In the test, the knee joint is bent at 30°; the ankle is stabilized and the knee is pushed outwards. If a greater abduction is possible than normal, the test can be evaluated as positive and is an indication of a tear of the knee outer ligament.
If the cruciate ligament is injured by a distortion, the meniscus is also damaged.
One of the standard tests for meniscus injury is the McMurray test.
The patient lies on his back, the leg is raised; the doctor bends the knee, then stretches the leg while turning the knee; the meniscus is stretched. If there is a meniscus injury, this movement causes a clicking sound.
The knee would have to “click” every time the test is performed.
Technical examination procedures
X-ray examination is a procedure that uses X-rays to create images of internal body structures, especially bones (to evaluate possible fractures).
With an ultrasound examination, only the collateral ligaments can be assessed, so it is not very helpful.
Magnetic resonance uses a magnetic field to create images of the inside of the body in order to be able to assess whether a ligament is completely torn or torn.
Arthroscopy is a surgical procedure in which a small endoscope provides insight into the inside of the knee; it is one of the most accurate examination methods, but it is invasive.
What to do? How is the treatment carried out
1) RICE protocol (also called PITCH rule): The best therapy in the first two days usually corresponds to the treatment of acute inflammation: protection, immobilization, cooling, bandage (bandage), high position.
These measures relieve pain, swelling and accelerate healing.
Anti-inflammatory tablets (e.g. Alrheumun, Voltaren and Dolormin) or the application of a clay or arnica ointment help against the pain.
2) Physiotherapy and rehabilitation: As soon as possible, exercises should be performed to regain the strength, movement and joint function of the knee. The care is provided by a physiotherapist, who compiles the exercises and creates an appropriate step program to fully regain functionality.
Rehabilitation in the swimming pool is useful if the patient has difficulty putting weight on the leg.
There are methods that accelerate recovery; for example, magnetic, ultrasound, Tecar and laser therapy are helpful for a swollen knee and to relieve pain.
3) The doctor may recommend wearing a bandage to relieve the pain and give the knee greater stability after the sprain. Usually, a normal knee pad is sufficient, which is also not particularly expensive. If greater support is required, more complex bandages are helpful.
If the doctor assumes that it is a simple distortion of the knee and does not order further examinations, the trauma is probably not particularly serious and there is a slight distortion of 1st or 2nd degree.
A 3rd degree distortion (i.e. a complete rupture) can often be treated in the same way as a 1st and 2nd degree strain, even if recovery takes longer. An operation is recommended if the knee continues to give way even after the rehabilitation program has been completed.
How long does recovery take? The prognosis
If there is an injury to the ligaments or meniscus, other times apply, especially if surgery has been performed.
As a rule, they subside pain in a 1st degree sprain within 7-10 days, while the duration of swelling varies. In some cases, the knee joint does not swell at all, in others, however, the effusion (fluid) can last for a few weeks.
The patient is allowed to walk, but should not overdo it so as not to delay the healing times.