Symptoms

Severe pain along the thigh and lower leg is one of the typical side effects of a bony contusion of the knee. The pain caused by the enormous force applied is already apparent in most of the patients affected when they are at rest. If the injured knee continues to be loaded despite the presence of a bruise, the pain usually increases in intensity.

In addition, a bruise on the knee typically results in extensive bruising (hematomas). In some of the patients affected, the extent of the injury is so severe that bleeding into the joint capsule (knee joint effusion) develops. In addition, the bruise on the knee often causes a restriction of the normal range of motion. As a rule, the ability to stretch and bend the knee joint in particular is negatively affected.

Causes

The most common cause of a bruise on the knee is a direct, blunt force impact on the knee joint. Depending on the exact location of the bruise on the knee, soft tissue is pressed and squeezed either against the bony structures or against the joint capsule. In addition, shear forces acting laterally on the knee joint can lead to a displacement of the soft tissue against the bone or the joint capsule.

In the end, the actual contusion is caused by the rupture of tiny and/or medium-sized blood or lymph vessels. Through the tears in the vessel walls, blood or lymph fluid can escape and seep into the intercellular spaces. This leads to the formation of a bruise within the joint capsule or along the bony structures of the knee joint.In most cases, a bruise on the knee is caused directly during the practice of sports activities.

The bruise on the knee is therefore considered a typical sports injury. People who regularly play soccer are particularly at risk. The reason for this is the fact that blunt force is often applied during the duels during the game. In addition, accidents at home, at work or when children are playing are the most common causes of knee bruises.