Popliteal cyst - The Baker's Cyst of the Knee

12 months ago

When you hear the word Baker's Cyst, it isn't an ingredient used by bakers, neither is it a recipe. Have you seen people that when they stands straight has a lump or bulg at the back of their knee? So many of them see it as a normal thing since they do not feel pain, but overtime they begin to feel discomfort. A person I was talking to some time back, attributed his to long time walking as a marketer. He said he would work for so many kilometer because he had to meet his target. This person currently is suffering from Baker's cyst currently as well as Rheumatoid Arthritis.

It is a condition known as Popliteal cyst and it is a fluid filled sac/cyst that is experienced behind the knee at the popliteal fossa. This condition can occur as a result of an increase in the size of the gastrocnemius semimembranosus bursa, for shorter prononciation GS Bursa which is a fluid filled sac present in between the semimembranosus and the medial head of gastrocnemius which is located at the medial aspect of the popliteal fossa. The fluid in the sac becomes increased as a result of fluid distension of the person.

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When it comes to having a mass behind the knee, Baker's cyst is the most common cause of this condition and it can be associated with other conditions of the knee such as Rheumatoid arthritis, knee osteoarthritis, meniscal tears and so on. This condition can occur as a result of a knee injury and the over usage of the knee can also lead to this condition, so this means that the older the person, the more likely chance of having the condition, although it is common in people within the age of aged 35 to 70 years. Like I said, the popliteal fossa is behind the knee, and it is covered and demacated by different muscles including the semitendinosus muscle, the semimembranosus muscle, the biceps femoris muscle, the medial head of the gastrocnemius muscle, and the lateral head of the gastrocnemius muscle.

It pathophysiology wouldn't be anything different from what I mentioned previously. It would be the enlargement of the gastrocnemius semimembranosus bursa (GS Bursa) leading to the distension of fluid. This can be occur from trauma to the GS bursa which leads to an enlargement of the bursa. Trauma can cause the fluid from the joint to interact with the fluid in the cyst leading to an increase in the cyst size, herniation of the joint capsule into the popliteal fossa. If there is excessive pressure on the knee joint, it can lead to the enlargement of the cyst. Having a valve between the space of the joint and the cyst leading to the trapping of fluid within the popliteal fossa.

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When baker's cyst occurs most patients are assymptomatic as they do not display symptoms but would just have the cyst bulging at the back of the knee. This can lead to knee joint tightness causing the inability to move and it would lead to discomfort. In the case of a degeneration of the Knee joint, it can cause knee pain but this is always identified with other knee conditions. The rupturing of the knee can also cause the leg to swell, somewhat like a deep vein thrombosis. The fluid will extend to the intrastitial areas around the knee and to parts of the leg.

Diagnosis of the cyst is usually clinical as the patients would be standing to allow the clinician see the mass behind the knee. While diagnosing, looking for Foucher's sign where the cyst isn't seen when the knee is flexed at a 45 degree angle. To identify the cyst, imaging such as MRI, Radiology, and Ultrasonography can be used to diagnose the condition. WHen this is done, modification of activity such as rest is adviced as a way of treatment if it doesn't have any symptomatic signs. In the case of pains in patients, using Non-Steroidal anti-inflammatories (NSAIDs) would be used. Steroid injections can also be used, and in cases where a removal is needed, aspiration of the cyst is done, as a well as surgery where there is an open cyst excision.