The knee joint suddenly swelled up.

Sudden swelling in the leg joint may be caused by meniscus injury, synovitis, gout, and other reasons. A detailed analysis is as follows:

1. Meniscus Injury

Twisting injuries or long-term cumulative overload on the knee joint can disrupt the integrity and continuity of the meniscus, leading to meniscus damage. Patients may experience symptoms such as knee swelling, limited mobility, joint pain, and joint clicking. In more severe cases, medications such as diclofenac sodium sustained-release tablets or piroxicam tablets may be taken under medical guidance.

2. Synovitis

Trauma, infection, immune abnormalities, and other factors may cause rupture and congestion of the synovial tissue in the knee joint, resulting in synovitis and the production of a large amount of fluid within the joint cavity. This manifests as swelling and pain in the affected leg joint. For synovitis, patients may take loxoprofen sodium tablets, ibuprofen tablets, or similar medications under medical advice to relieve symptoms.

3. Gout

This is usually caused by poor dietary habits. Excessive uric acid production and purine metabolism disorders lead to elevated uric acid levels, forming urate crystals that deposit in joints, causing joint damage and resulting in swelling in multiple leg joints. To address urate crystal deposition due to gout, patients may take indomethacin enteric-coated tablets or diclofenac sodium sustained-release tablets as advised by a physician. In severe cases, surgical intervention may be required.

In addition, swelling could also result from factors such as bone spurs, poor venous return in the lower limbs, venous thrombosis, or vascular compression. It is recommended that patients seek timely medical attention upon experiencing the above symptoms and receive appropriate treatment to prevent worsening of the condition.