​Kembara Xtra - Medicine - Popliteal ( Baker) Cyst

​Kembara Xtra - Medicine - Popliteal ( Baker) Cyst
a fluid-filled synovial sac that develops in the popliteal fossa as a result of the gastrocnemius membranous bursa (usually) distensing; not a real cyst either unilaterally or bilaterally
 The knee's most common cystic mass Primary cysts are a bursa distention that develops on its own without an intra-articular disease.
If the bursa and knee joint can communicate, allowing articular fluid to fill the cyst, further cysts will develop.
 Associated with inflammation of the synovium

Epidemiology 
Primary cysts are typically observed in children under the age of 15, and secondary cysts are typically seen in adults. Incidence is bimodal, with children ages 4 to 7 years and adults ages increasing with age.
Adult prevalence ranges from 19 to 47 percent in symptomatic knees and from 2 to 5 percent in asymptomatic knees. In children, the prevalence is 6.3 percent in symptomatic knees and 2.4% in asymptomatic knees.


Pathophysiology and Etiology 

Meniscal tears, typically of the posterior horn, anterior cruciate ligament (ACL) insufficiency, and degenerative articular cartilage lesions are examples of associated intra-articular disease.  (20%) Rheumatoid arthritis
(50%) Osteoarthritis
Gout (14%) and osteochondritis (8%)
Other possible causes
Lymphoma, Sarcoidosis, Polyarthritis, Villonodular Synovitis, Infectious Arthritis, and Connective Tissue Disorders
Direct trauma to the bursa is probably the main cause in children because there is no communication between the bursa and the joint. Other possible causes include extension or herniation of the synovial membrane of the knee joint capsule or connection of the normal bursa with the joint capsule.
It has been detailed how a valve-like mechanism allows fluid to move one way from the joint to the bursal connection.

Meniscal degeneration or tear, advancing age, rheumatoid arthritis, osteoarthritis of the knee (the most frequent kind), ligamentous trauma, and ligamentous insufficiency are all risk factors.

Accompanying Conditions 

any illness that results in knee joint effusion

Diagnosis: Painless lump in the popliteal fossa. Most cysts have no symptoms.
Large cysts may cause entrapment neuropathy of the tibial nerve, dull ache if cyst is large enough to restrict joint motion—typically a restriction of flexion, painful if cyst ruptures, vascular compression, most commonly of the popliteal vein, may result in claudication or thrombophlebitis, and activity changes cyst size.

clinical assessment 
Examine while the joint is fully extended and 90 degrees flexed.
Mass grows with extension and vanishes with flexion, according to the Foucher sign.
Most frequently located in the medial aspect of the popliteal fossa, medial to the neurovascular bundle and lateral to the head of the gastrocnemius. When the knee is slightly flexed, it is easiest to palpate the cyst, which can occasionally be fluctuant or painful.
Transillumination makes it easier to tell a cyst from a solid mass.
Ruptured cysts are often painful, accompanied by swelling and bruising along the medial malleolus of the ipsilateral calf and ankle (crescent sign).
In rare cases, compartment syndrome and pseudothrombophlebitis are also linked to ruptured cysts.


Multiple Diagnoses 

Xanthoma, Lipoma, Liposarcoma, Fibroma, Fibrosarcoma, Vascular tumor, Popliteal vein varices, Infection/abscess, Ganglion cyst, Hematoma, Thrombophlebitis, Aneurysm (rare), and Muscular herniation (rare, resulting from trauma).

Laboratory Results 
Initial examinations (lab, imaging)
CBC, ESR (if suspected septic arthritis) Prior to aspiration, make sure there is no popliteal aneurysm. In order to identify whether the fluid is infectious, inflammatory, or mechanical, send the aspirate for cell count and culture.
 Ultrasound confirms the presence and size; Doppler can distinguish Baker cysts from soft tissue tumors, DVT, and popliteal vascular aneurysms.
MRI can be used to evaluate internal joint structural derangements and spot cyst leaks.

Tests in the Future & Special Considerations

 When testing children, prefer observation to invasive methods.
Radiographs may demonstrate posterior soft tissue density.
CT arthrography is preferable for imaging cystic features and can help identify lipomas, aneurysms, and malignancies from cysts. Arthrography may show communication with joint capsule or rupture.

therapy of any associated underlying diseases. Compressive wrap or sleeve for comfort. No therapy if asymptomatic.

Medication 

Treat the underlying problem if the cellular fluid investigation reveals the etiology.
NSAIDs and first-line analgesics for symptom relief

Further Treatments
Physical treatment helps knee strength and range of motion, especially when there is concurrent disease.
 Needle aspiration provides momentary relief; recurrence is common.
 Increased joint range of motion, relief from knee discomfort and edema, along with a corresponding decrease in bursa size following aspiration and intra-articular/intracystic corticosteroid injection
The best gains in pain, function, and cyst size come from a combination of physical therapy and corticosteroid injection with or without aspiration.
 In modest studies, ethanol or dextrose/sodium morrhuate injections for sclerotherapy have had positive outcomes.


Excision is a surgical option to consider if symptoms are unresponsive to treatment if no underlying cause can be identified.
Recurrence following routine surgery is common and is highest if chondral lesions are present. Surgery is typically not necessary in youngsters.
If a valvular mechanism is found and intra-articular pathology is treated, arthroscopic surgery is very effective. Excision by arthroscopy or open surgery frequently necessitates concurrent treatment of underlying pathology.

Variable prognosis; many cysts are asymptomatic; some cysts disappear with therapy of underlying causes (such as gout or rheumatoid arthritis).
The majority of cysts in children disappear on their own.


Complications include: Hemorrhage into cyst if using anticoagulants; Compartment syndrome in a ruptured cyst; Thrombophlebitis from compression of the popliteal vein; Infection of the popliteal cyst.

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