Baker's cyst | |
---|---|
Other names | Popliteal cyst[1] |
![]() | |
Ultrasound image of Baker's cyst | |
Specialty | Rheumatology ![]() |
Symptoms | None, swelling behind the knee, stiffness, pain[1][2] |
Complications | Deep vein thrombosis, peripheral neuropathy, ischemia, compartment syndrome[2][3] |
Usual onset | Gradual[1] |
Risk factors | Knee problems such as osteoarthritis, meniscal tears, rheumatoid arthritis[1][3][4] |
Diagnostic method | Confirmed by ultrasound or MRI[3] |
Differential diagnosis | Deep venous thrombosis, aneurysms, ganglion, tumors[1] |
Treatment | Supportive care, aspiration, surgery[1] |
Frequency | c. 20%[2][3] |
A Baker's cyst, also known as a popliteal cyst, is a type of fluid collection behind the knee.[4] Often there are no symptoms.[2] If symptoms do occur these may include swelling and pain behind the knee, or knee stiffness.[1] If the cyst breaks open, pain may significantly increase with swelling of the calf.[1] Rarely complications such as deep vein thrombosis, peripheral neuropathy, ischemia, or compartment syndrome may occur.[2][3]
Risk factors include other knee problems such as osteoarthritis, meniscal tears, or rheumatoid arthritis.[1][3][4] The underlying mechanism involves the flow of synovial fluid from the knee joint to the gastrocnemio-semimembranosus bursa, resulting in its expansion.[1] The diagnosis may be confirmed with ultrasound or magnetic resonance imaging (MRI).[3]
Treatment is initially with supportive care.[1] If this is not effective aspiration and steroid injection or surgical removal may be carried out.[1] Around 20% of people have a Baker's cyst.[2][3] They occur most commonly in those 35 to 70 years old.[4] It is named after the surgeon who first described it, William Morrant Baker (1838–1896).[5]