Baker’s cyst

In the back of the knee , at the level of the popliteal muscle (musculus popliteus), a protuberance of the bursa of the two-headed calf muscle ( musculus gastrocnemius ) or the semimembranous muscle (musculus semimembanosus) can form , which appears like a blister in the popliteal fossa.

Children, especially boys up to the age of 15, are often affected by popliteal cysts , which usually occur without symptoms.

An inflamed Baker’s cyst is almost never bilateral and is equally likely to affect the right or left knee.
Baker’s cyst is not dangerous and has no long-term consequences.


What Are the Causes of a Baker’s Cyst?

The excess synovial fluid accumulates and forms a BAKER pseudocyst, since the true cyst is found practically only in children.
It usually occurs as a result of another disease of the knee joint: meniscus tear , rheumatoid arthritis , lesion of the anterior cruciate ligament , cartilage changes, osteoarthritis , etc.

The inflammatory fluid from joint disease accumulates in the joint, but is not absorbed there, and can continue to the back of the knee. Another mechanism leading to the formation of the popliteal cyst is inflammation of the bursa (bursitis); the effusion causes the bursa to enlarge, which expands into a less compact area, the popliteal fossa.

What are the symptoms?

Adults experience diffuse discomfort in the back of the knee and a feeling that the cyst “pulls” when bending and straightening the leg; they also complain of joint impairment, the impossibility of continuing to exercise and – in severe cases – neurological deficits. The knee is only swollen
at the back .

How is the diagnosis made?

The posterior tendons of the thigh can suffer from acute tendinitis, which can be confused with Baker’s cyst.
Posterior knee pain is often misdiagnosed as a Baker’s cyst, but the majority of cases involve a cartilage lesion, tendinitis of the popliteal fossa, hamstring biceps, hamstrings, or calf biceps tendons.

During the examination, the doctor will notice swelling in the back of the knee. Magnetic resonance
imaging is a suitable diagnostic imaging method  because Baker’s cysts are often a secondary manifestation of another knee disease and NMR is the only form of examination that can provide a detailed picture of the remaining structures of the knee joint . The differential diagnosis must consider the possibility of a tumor. An ultrasound scan shows the size of the cyst, but does not show any damage inside the knee joint.

What can you do? Which therapy is suitable?

Most cysts will go away on their own over time, but there is no way to predict with certainty if and when this will happen.
Normally there is  no need to suck out the liquid  because new liquid would be formed in a very short time.
Children are expected to heal spontaneously, while adults can be treated with cortisone infiltration , but recurrence is possible if the causes of the cyst formation are not addressed.
Cortisone also has many side effects .

Instrumental physiotherapy (e.g. Tecar or magnetic therapy ) only makes sense in the case of arthrosis in the knee joint ; in the other cases, the primary cause of the knee inflammation must first be eliminated and, as a rule, the intervention of a doctor is necessary.

Kinesio taping for the back of the knee

It is used to drain the popliteal lymph nodes. Effect: draining. Shape: a fan-shaped strip. Length: 15-20cm. Attach the tape without stretching with the knee stretched out in the form of a fan in the hollow of the knee. Very effective when combined with the double fan at the front of the knee.

When is an operation necessary?

If the cyst ruptures , the knee becomes inflamed, as if after trauma, with pain, swelling, redness, and overheating.

A painful and large cyst can be surgically removed, but even in this case it can form again if the causes are not treated (e.g. meniscus injury).
Today, the cysts are removed using an open surgical technique; the procedure consists of an incision and complete removal of the cyst; then the capsule is sewn so that it does not give way in the future.

The first days after the operation, the RICE protocol is used, which includes immobilization, ice and elevation of the operated leg; the knee is put in a cast or immobilized with a splint for three days. Passive mobilization
is started cautiously as soon as possible , and the patient should begin active mobilization within one week after the procedure.

In the second week , the scar is mobilized to avoid the formation of uncomfortable scar adhesions that impede movement.
When walking, crutches such as crutches are used at first and then gradually abandoned as the pain subsides.

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