Definition
Bursa sacs are flat, fluid-filled, pillow-like tissue structures that are embedded between hard (e.g. bones) and soft (e.g. muscles) structures. They are located near joints, i.e. in the area of increased mechanical stress, such as the knee.
The forces acting on the joints are reduced and damped by the bursae. Thus the knee joint is naturally protected. If this bursa located in the knee joint becomes inflamed, it is called bursitis of the knee.
The inflammation leads to increased fluid retention in the bursa, causing it to expand. The increase in size can lead to constriction of adjacent structures such as muscles or nerves. The consequences are pain in the knee and restricted movement in the knee.
Cause
Mechanical overload The most common cause of bursitis in the knee is mechanical overload. Repeated physically sustained activities with main stress in the area of the knee joint, (such as those performed by top athletes or tilers) lead to permanent irritation and constant pressure on the knee. Small injuries occur within the bursa, which ultimately lead to inflammation.
Injuries to the knee Accidents and injuries can also be the cause of bursitis in the knee. For example, a dull blow can cause the bursa to fill with blood and thus cause an inflammation. If there is an open wound in the area of the knee, bacteria or other microorganisms can enter it, infect it and cause bursitis of the knee (foreign bodies remaining in the wound after accidents or injuries, such as splinters, can also inflame the bursa).
Diseases of the locomotor system and metabolic diseases Various diseases can cause bursitis of the knee. It is possible that diseases of the musculoskeletal system, which are accompanied by changes in the joints (e.g. knee arthrosis), lead to an increased load on the bursa in the knee due to the changed joint structures and cause bursitis. Metabolic diseases, such as gout, in which uric acid crystals are deposited inside the joints, can also trigger an inflammation of the bursae in the knee.
A very rare cause of bursitis is tuberculosis, which is caused by bacteria.
- Mechanical overloadThe most common cause of bursitis in the knee is mechanical overload. Repeated physically sustained activities with main stress in the area of the knee joint, (such as those performed by top athletes or tilers) lead to permanent irritation and constant pressure on the knee.
Small injuries occur within the bursa, which ultimately lead to inflammation.
- Injuries to the kneeAccidents and injuries can also be the cause of bursitis in the knee. For example, a dull blow can cause the bursa to fill with blood and thus cause an inflammation. In the case of an open wound in the area of the knee, bacteria or other microorganisms can enter it, infect it and cause bursitis of the knee (foreign bodies remaining in the wound after accidents or injuries, such as splinters, can also inflame the bursa).
- Diseases of the locomotor system and metabolic diseasesVarious diseases can cause bursitis of the knee. It is possible that diseases of the musculoskeletal system, which are accompanied by changes in the joints (e.g. knee arthrosis), lead to an increased load on the bursa in the knee due to the changed joint structures and cause bursitis. Metabolic diseases, such as gout, in which uric acid crystals are deposited inside the joints, can also trigger an inflammation of the bursae in the knee.
- A very rare cause of bursitis is tuberculosis, which is caused by bacteria.
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