Overview
A burst cyst can cause calf swelling and pain that looks like a blood clot.
Symptoms
Common signs:
- Swelling behind the knee
- Lump or swelling behind the knee
Less common
- Tightness
- Ache
When to get medical care
Call 911Chest pain or shortness of breath.
Get care todaySudden calf swelling, redness, or pain.
See a doctor soonA lump behind the knee.
Causes
Knee fluid.
Does it spread or run in families?
- It isn't contagious. You can't catch it from someone else.
Who is more likely to get it
- Arthritis
Possible complications
Diagnosis
A clinician examines.
Tests
Tests, if needed:
- Ultrasound: Rules out a clot.
Treatment
Treat the knee problem.
Self-care
- Rest from activities that hurt
- Ice for 15 to 20 minutes a few times a day
- Raise the area when you can
- Gentle exercises
Medicines
Medicines that may help:
| Medicine | Helps with | Good to know |
|---|---|---|
| Pain relievers | Pain and swelling | Ask first if you have kidney, stomach, or heart problems. |
OwieClear doesn't give doses: follow the label or your healthcare professional. Medicine names here are examples, not a full list.
Which doctor treats this
- Start with your primary care provider (family doctor or internist).
- They may send you to an orthopedist (bone and joint doctor).
Pregnancy and breastfeeding
- If you're pregnant or planning to be, tell your prenatal provider about this condition.
- Don't start or stop any medicine on your own. Some are safe in pregnancy and some need to be changed.
- Ask before taking any pain reliever. The FDA advises avoiding ibuprofen and naproxen after 20 weeks unless your doctor says to.
- Breastfeeding: Most medicines are fine, but ask. The NIH LactMed database lists what's known about each one.
Outlook
Often goes away.
Research studies
Research studies test new ways to find and treat health problems. Some are looking for volunteers. Talk with your doctor before joining one.
Sources
Last updated 2026-11-12.