Swollen knee is commonly called as “water on the knee”. There can be several reasons for swelling or inflammation of the knee and the pain associated with swollen knee can be mild to severe. The swelling can be acute or due to sudden injury and sometimes it can be gradual process due to accumulation of synovial fluid. Similarly swelling can be inside the knee or in its neighboring regions. Before the doctor begins treatment, he should find out what exactly is the cause of swollen knee.
Mechanism Of The Knee :
Knee joint is in the form of capsule having some space inside. This space contains lubricating fluid for facilitating flexible knee movement. But due to some reasons, there may be excess of fluid accumulation inside the space causing swollen knee. It is called as “knee effusion”.
Swollen Knee Causes :
There are two major categories of swollen knee. The first one is fluid accumulation inside the knee joint. This is caused due to two conditions namely acute and chronic.
- Acute :
Injury or trauma that has caused knee to swell recently is one of the reasons. Acute injury can occur to anyone during a fall thereby causing accumulation of blood inside the knee. It can be due to ACL tear or even a fracture or damage of cartilages inside. This type of acute accident can cause the knee to develop swelling within minutes because of the fluid pressure inside. Sometimes, meniscus tear or sprain on the knee can cause fluid (not blood) to collect inside the joint space. But this type of injury takes enough time (delayed swelling) and sometimes days to develop inflammation. Here the amount of synovial fluid gets collected inside may vary significantly however this type of tear or sprain does not produce any tense moments like that of blood accumulation due to rapid injury.
- Chronic :
Second one is the chronic condition of knee swelling like that of arthritis, gout and infection inside. Chronic injury does not happen all of a sudden; rather it takes enough time since it is a gradual process. Sometimes there may be pain and sometimes not. In rare cases, there can be rapid swelling without injury.