Fluid in the knee joint (its other names: synovium, synovial fluid) is a thick elastic mass that fills the articular cavity. This is a kind of articular lubricant that performs a shock-absorbing function: it prevents friction of the articulated articular surfaces, protects the articular structures from wear, provides nourishment for the cartilage and metabolism with it.
This fluid is produced by the epithelial cells of the synovial membrane of the joint capsule. Normally, its content does not exceed 2-3 ml.
Excessive production of synovial fluid (then called “effusion”) is not a separate disease; this is only one of the manifestations of injury or inflammation (synovial sac or other element of the knee joint).
Due to injuries, acute synovitis, bursitis and other inflammatory diseases of the joints, less often due to an allergic reaction to a certain type of allergens – the production of synovia increases, it accumulates in the synovial cavity, accompanied by local edema, soreness and other symptoms.
Depending on the cause of its excessive production, the composition of the liquid varies. She may be:
- transparent (serous),
- with admixture of flakes of fibrin (fibrinous),
- pus (purulent),
- blood (hemorrhagic).
The knee is one of the largest supporting joints, so it is more prone to injury and overload than many others. The probability of accumulation of excess fluid in its articular cavity due to similar reasons is higher than, for example, in the ankle, shoulder, or small joints.
The patient’s quality of life varies with the severity of the underlying disease or injury. Excessive synovial fluid plus inflammation leads to a restriction of movement in the damaged joint, affecting physical activity. It is also possible to increase pain when walking and even their appearance at rest, standing with reliance on the sore leg.
The treatment of pathologies and injuries that lead to an excess of effusion is performed by a traumatologist, rheumatologist, arthrologist or surgeon.
It is important whether the underlying causes of the disease start treatment as early as possible. Otherwise, irreversible changes in the cartilage and synovial membrane may develop, which will inevitably lead to impaired motor function of the leg. With purulent inflammation, the development of a life-threatening patient’s sepsis is not excluded.
Further from the article you will learn about the specific causes of the pathological production of joint fluid, the symptoms accompanying this condition, and the methods of conservative and surgical treatment.
Causes of increased formation of synovial fluid
Excess effusion can be a sign of many diseases and pathological conditions. The table lists the specific types of injuries and illnesses that can lead to this problem:
(if the table is not fully visible – scroll it to the right)
Injuries: falling on the knee, hitting, landing on feet from a great height
Fracture of the articular bones (femur or tibia in the area of the knee joint, patella);