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Swelling behind the knee

A swelling behind the knee is usually the knee's own fluid in a natural pouch. It is not a growth, and it is a sign of what the joint is doing rather than a problem in its own right.

Do not wait for an appointment

  • The calf suddenly becomes painful, swollen, hot or tight
  • You become breathless or develop chest pain
  • The knee becomes hot and red and you feel feverish
  • The swelling appears quickly and is hard, rather than soft and gradual
Sheet 30 · Knee exercisesHip & kneeSettles as the knee settles

Do this

  • Understand what it is first: a pouch of the knee's own fluid, pushed out behind the joint. The cyst is a sign, not the disease
  • Treat the knee, not the lump. Whatever is irritating the joint — arthritis, a cartilage tear — is what is making the fluid
  • Do the knee exercises. A calmer joint makes less fluid, and the cyst shrinks with it
  • Have it examined once, so we are sure it is a cyst and not something else
  • Come back if it suddenly becomes painful, or if the calf changes

Avoid this

  • Asking for the lump to be removed as a first step. Cysts that are cut out without treating the knee come back
  • Squeezing or massaging it firmly
  • Ignoring a sudden calf swelling and assuming it is just the cyst. It may be, but a clot behind the knee looks similar and must be ruled out
  • Long periods on the feet while the knee is flared

The questions everybody asks

Is it a tumour?

No.

It is the knee's own joint fluid in a pouch. It is not a growth and it does not turn into one. The word "cyst" worries people more than the thing itself deserves.

Why did it appear?

Because the knee is making extra fluid.

A joint that is irritated produces more fluid than usual. The fluid takes the path of least resistance, which is backwards, into a natural pouch behind the knee. That is the swelling you can feel.

What if it bursts?

You will feel sudden pain and swelling in the calf.

It settles on its own over a week or two, but it looks exactly like a clot in the leg, and that is dangerous. So if the calf suddenly changes, be seen the same day. Do not decide for yourself which one it is.

Does it need an operation?

Almost never on its own.

Treating the knee usually settles it. If the knee needs a procedure for its own reasons, the cyst often disappears afterwards without being touched.

Open the exercise sheet

Pictures, how many and how often, and what it should feel like. Free, and printable.

Guides for you

In your language, free to download. Each one is a short PDF you can keep on your phone or print.

Starting to Exercise Safely Englishहिंदीमराठी
Your Pain and Swelling Tablets Englishहिंदीमराठी
X-ray, CT and MRI — What to Expect Englishहिंदीमराठी
When to Come Back Urgently Englishहिंदीमराठी

On cost: if we suggest a scan, an injection or an operation, ask us what it costs and what happens if you do nothing. We will answer both. You should never feel pushed into spending money.

Consultation is ₹500 for a first visit and ₹300 for a follow-up, the same at both clinics. For anything else, ask at the desk or on WhatsApp before it is done — we will tell you the exact cost.

Should you come and see us?

A page is a starting point, not a diagnosis. If the pain is not settling, come in and have it looked at properly — bring any X-ray, MRI or CT films you already have.

Nallasopara West

Opposite Patil Hospital

Shop No. 14, Veena Apartment,
Opposite Patil Hospital, near Panchmukhi Hanuman Mandir,
S.T. Stand Road, Nallasopara West — 401203

Monday to Saturday
12:00 noon – 2:00 pm  ·  7:30 pm – 9:30 pm
Sunday by prior appointment only

Call 87665 22099

Virar East

Opposite Parimal Hospital

Shop No. 7, Damodar Tower,
Opposite Parimal Hospital, Morya Nagar,
Manvel Pada Road, Virar East — 401305

Monday to Saturday
5:30 pm – 7:30 pm
Sunday by prior appointment only

Call 92702 84859

Other conditions

Ready when you are.

Call either clinic during consulting hours, or send a WhatsApp message any time.

Nallasopara West Virar East