Noticing swelling in just one knee can be concerning, especially when the other knee feels normal.
While swelling in both knees often suggests a systemic issue like arthritis, swelling in one knee usually points to a localized problem.
Common causes include injuries like ligament or meniscus tears, bursitis from repeated pressure, Baker’s cysts, and inflammatory conditions like gout or pseudogout.
Infections like septic arthritis can also cause sudden swelling and require urgent care. Sometimes arthritis or tendonitis affects only one knee, especially if it’s been overused or injured.
You should seek medical attention if the swelling is severe, sudden, painful, accompanied by fever, or doesn’t improve with rest. For minor swelling, use the RICE method (Rest, Ice, Compression, Elevation) and over-the-counter anti-inflammatories. Paying attention to your symptoms and acting early can help prevent complications and support faster healing.