Popliteal (Baker) cyst

Last updated: March 14, 2023

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Popliteal cyst, also called Baker cyst, is a synovial fluid-filled distention of a bursa in the popliteal fossa. It can be idiopathic or associated with underlying conditions, e.g., meniscal tear or osteoarthritis. Popliteal cysts are often discovered incidentally on imaging or physical examination but can also cause posterior knee pain and/or limit knee flexion. Large or ruptured cysts can cause calf swelling and may mimic the signs and symptoms of DVT. The diagnosis is usually clinical, but ultrasound is often used to exclude DVT and confirm the diagnosis. X-ray and/or MRI can be obtained to assess for underlying joint disease. Management of symptomatic cysts typically involves a trial of nonsurgical measures, e.g., pain management with NSAIDs and cyst drainage. Surgical resection may be considered for complications such as neurovascular compression or for persistent symptomatic cysts.

Popliteal cysts are typically asymptomatic and found incidentally on physical examination or imaging. [2][3]

A palpable change in cyst consistency when flexing or extending the knee differentiates popliteal cysts from other masses, which are not affected by knee position. [3]

Obtain an ultrasound, as a large or ruptured popliteal cyst may cause calf swelling and can mimic the signs of DVT (pseudothrombophlebitis syndrome). [2]

The differential diagnoses listed here are not exhaustive.

  • Asymptomatic cysts: Treatment is not required in most cases. [2][3]
  • Symptomatic cysts [2][3]
    • Nonsurgical management: preferred for at least 6 weeks if there are no neurovascular complications [3]
    • Surgical resection: for persistent symptoms and/or neurovascular compression
  • Ruptured popliteal cyst: conservative treatment, e.g., pain relief, rest, elevation

Consider referral to orthopedics for persistent symptomatic popliteal cyst despite conservative measures.

We list the most important complications. The selection is not exhaustive.

  1. Herman AM, Marzo JM. Popliteal Cysts: A Current Review. Orthopedics. 2014; 37 (8). doi: 10.3928/01477447-20140728-52 . | Open in Read by QxMD
  2. Walls R, Hockberger R, Gausche-Hill M, Erickson TB, Wilcox SR. Rosen's Emergency Medicine 10th edition- Concepts and Clinical Practice E-Book. Elsevier Health Sciences ; 2022
  3. Frush TJ, Noyes FR. Baker’s Cyst. Sports Health. 2014; 7 (4): p.359-365. doi: 10.1177/1941738113520130 . | Open in Read by QxMD
  4. Mizumoto J. The crescent sign of ruptured baker's cyst. J Gen Fam Med. 2019; 20 (5): p.215-216. doi: 10.1002/jgf2.261 . | Open in Read by QxMD

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