What is a Baker's Cyst?

What Causes a Baker's Cyst?

When there is inflammation or damage inside the knee, the joint produces excess fluid. This fluid fills a natural sac behind the knee and, like a one-way valve, cannot flow back. Meniscus tears, cartilage damage, knee osteoarthritis and rheumatic diseases are the most common causes.

Symptoms

• A soft swelling behind the knee, more visible when standing
• A feeling of tightness when fully bending or straightening the knee
• Discomfort increasing after long walks or standing
• If the cyst ruptures, sudden calf pain, swelling and redness

Frequently Asked Questions

Does a Baker's cyst need surgery?

Usually not. Treatment targets the knee problem that created the cyst; once it improves, the cyst usually shrinks. Sudden calf swelling and pain require prompt examination to rule out a deep vein thrombosis, which can cause similar symptoms.