Bruise on the knee

Introduction

A bruise in the knee is also known as “haemarthros”. The common word “haematoma” is synonymous with bruises on all parts of the body. A bruise can be thought of as the filling of a tissue with blood as a result of an injury or accident.

General information

Almost all tissues of the human body are supplied with blood, which contains oxygen and nutrients. If the affected tissue, in this case the structures of the knee, is damaged, the blood vessels can also be damaged. The blood then exits the vessel and deposits in the tissue and body cavities.

From there, the blood can no longer be transported through the veins and the damage in the vessel leads to the affected area filling with blood and thickening. Very often we observe the development and course of bruising when we get a so-called “bruise“. The area of the bruise becomes thicker, warmer and can also be painful to touch.

After a few days the colour changes to a more yellowish spot before the bruise disappears completely. A bruise on the knee, on the other hand, is a common side effect of sports injuries. Due to the high level of stress in everyday life, the knee joint is very susceptible to injuries to the ligamentous apparatus, cartilage or bone.

Common causes of bruising are torn meniscus, torn collateral ligaments, torn cruciate ligaments or broken bones. Joint effusions in the knee are often extremely painful, the knee swells and turns a blue-greenish colour that is visible from the outside. Some household remedies can be used as immediate measures, such as rapid cooling of the knee, which reduces bleeding.

A doctor should then be consulted as soon as possible, as not only is the causal injury in need of treatment, but the bruise itself can cause permanent damage to the knee. Under certain circumstances, joint effusions can form after knee operations, for example on the meniscus or cruciate ligament. If the bruise does not disappear by itself after some time, medication can promote faster healing.

In some cases, it may be necessary to puncture the joint by using a needle to suck the fluid directly out of the cavities in the joint. Another treatment for bruises in the knee is the so-called “haematoma tapes”. These are stuck tightly onto the joint from the outside and can both alleviate the pain and accelerate the regression of the haematoma. Which could also be of interest to you: Knee puncture

Causes

Bruises in the knee joint can have a variety of causes. In most cases, they are the result of an injury to structures in the knee. Such injuries can occur without any apparent cause during everyday movements, as a long-term consequence of permanent incorrect loading and wear and tear or in connection with sports accidents.

High-risk sports for knee joint injuries are skiing and soccer, as well as all sports that require special strength and load on the legs. The knee joint is particularly prone to so-called “rotational trauma”. If the lower leg is twisted too much in relation to the upper leg by a strong, incorrect movement, the cruciate ligaments, the collateral ligaments and the two menisci can be particularly injured.

The extent of the injuries ranges from overstretching to the complete tearing of the ligaments. All torn ligaments in the knee are in urgent need of treatment by an orthopaedic surgeon. With the jerky injuries it often happens that vascular structures running through the knee are also injured.

The blood that is transported through them then pours into the surrounding tissue and the hollows of the knee joint. Any injuries in the knee, especially those involving the bones, for example the kneecap, can be caused by strong external forces, for example in severe falls. Both slight bruises and fractures of the bones can cause haematomas.

These bruises manifest themselves as so-called horse kisses. Bruises in the knee often occur after operations on the knee. The body perceives the operation as a kind of injury.

Some drugs can also cause bruising in different parts of the body. In this case, a doctor should be consulted to determine which medication is responsible for this and whether the drug therapy must be discontinued. In rare cases, a bruise in the knee can occur without any apparent cause and without a previous accident.

If something like this occurs more frequently, even in other parts of the body, it can sometimes indicate more serious diseases. A physician should be consulted to rule out internal diseases that include bleeding tendencies. Bleeding occurs during and after operations.

If a larger injury in the knee joint is treated surgically, small or larger secondary bleeding may occur within the joint cavities. During major operations, after which bleeding is probable, surgeons often place a drain in the surgical wound, through which the accumulating blood can drain off. If the bleeding seems to decrease or stop, this drainage can be removed.

It is still possible that a bruise may occur. Since the swelling can also be caused by, for example, bacterial pus, the effusion must be observed. If the effusion does not improve within a few days to weeks, a doctor must decide whether the knee needs to be punctured or even whether surgical treatment is necessary.

A bruise in the knee can also occur after an arthroscopy, i.e. a joint endoscopy. The insertion of medical instruments into the knee joint irritates the joint cavity and leads to swelling in the knee. If the intervention has a therapeutic aim – e.g. operating on a torn ligament in the knee or suturing a damaged cartilage – fine or even larger blood vessels, which are found in almost every tissue, are damaged.

These are not large, but rather diffuse bleedings, which, however, are significant in a narrow space such as the knee joint and can cause significant swelling with pain. However, a bruise in the knee after arthroscopy is a common side effect, which in most cases subsides on its own after some time and should not cause any concern. Only in exceptional cases can an infection occur, for example, which then needs further treatment.