Knee & Leg
Baker's Cyst
Also called: Popliteal cyst
A fluid-filled swelling behind the knee — almost always a messenger, not the message: the knee is producing extra fluid because of something inside (arthritis, meniscus tear), and the fluid pouches backward. Treat the source and the cyst typically follows.
Common signs
- Fullness or tightness behind the knee, worse after activity
- A palpable soft lump behind the knee, more obvious with the leg straight
- Stiffness with full bending
- Size fluctuates with the knee's irritation level
Seek help now if
- Sudden calf pain, swelling, redness — a ruptured cyst mimics a blood clot (DVT), and a DVT mimics a ruptured cyst: this combination gets urgent evaluation to tell them apart
- Fever with a hot swollen knee
- A hard, fixed, or rapidly growing mass
Any of these: call 911 or get to an emergency room first. Everything else can wait.
What to do first
- Identify the driver: exam ± imaging of the knee itself
- Manage the knee's irritation (load, strengthening, joint care) — the cyst is a barometer
- Compression and elevation for comfort during flares
If it's become chronic
- Persistent cysts track with unresolved joint pathology — revisit the primary diagnosis
- Drainage/injection offers temporary relief; recurrence is the rule unless the source is treated
Natural healing options we use
- Care directed at the underlying knee condition (see Knee OA / Meniscus entries)
- Manual therapy for calf and hamstring comfort
- PEMF; anti-inflammatory nutrition
About imaging
Ultrasound confirms the cyst (and excludes DVT when urgent); MRI evaluates the knee's internal driver.
Daily self-care
- Track cyst size against activity — it's biofeedback
- Keep the knee strong and mobile
- Urgent care for any sudden calf swelling — don't guess on clots
More in Knee & Leg
Knee OsteoarthritisPatellofemoral Pain SyndromePatellar TendinopathyACL Sprain / TearMCL SprainPCL SprainMeniscus TearIT Band Syndrome
Please read: this page is education, not a diagnosis. A proper examination is how a condition gets confirmed and a plan gets built. See our medical disclaimer.