Baker’s cyst is a bulge in the popliteal fossa, which is formed due to inflammation in the knee joint. Disease manifests clinically only when it has already reached such a size that it begins to squeeze the nerve trunks and vessels located in the popliteal fossa. The disease is accompanied by pain and restriction of flexion in the knee joint, numbness and paresthesia in the sole area are possible. The diagnosis is confirmed by MRI or knee ultrasound. Cyst punctures are used as treatment. According to the indications, an open or arthroscopic removal of the formation is performed.
M71.2 Synovial cyst of the popliteal region [Baker]
Baker’s cyst causes
In every second person, on the back surface of the knee joint, between the tendons of the semi-webbed and calf muscles, there is a mucous inter-tendon bag, which is a variant of the normal anatomical structure. With inflammation, fluid accumulates in the knee joint, which can penetrate through thin slits into the interstitial bag. As a result, the bag increases in size, there are pains and restriction of movements in the knee joint. Baker’s popliteal cyst is formed in metabolic-dystrophic (for example, in diseases and post-traumatic changes of the menisci) and inflammatory (rheumatoid arthritis, etc.) diseases.
Baker’s cyst symptoms
In the first stages, the disease is asymptomatic or accompanied by mild unpleasant sensations. With further enlargement, the cyst begins to squeeze the nerves located nearby, causing pain, tingling or numbness in the sole area and preventing the patient from completely bending the knee joint. Examination sometimes reveals a visible tumor-like formation in the popliteal fossa. To the touch, Baker’s cyst is elastic, dense. Her palpation is accompanied by mild soreness.
When the Baker’s cyst ruptures, fluid from the tendon bag penetrates into the muscles, causing pain and swelling along the back of the lower leg. In some cases, Baker’s cyst compresses the veins of the lower leg, leading to stagnation of blood, the development of phlebitis and the formation of blood clots. A detached blood clot can migrate to the lungs and cause a life–threatening complication of the patient – pulmonary embolism. In rare cases, cyst pressure on muscles, blood vessels and nerves causes compression syndrome – a gross violation of metabolic processes in bones and soft tissues, leading to the development of necrosis and osteomyelitis.
The diagnosis of Baker’s cyst is made by an orthopedic traumatologist based on the patient’s complaints, the characteristic clinical picture and the results of additional studies. Ultrasound and MRI of the knee joint are used to confirm the diagnosis. In difficult cases, knee arthroscopy is performed to diagnose or plan an operation.
Baker’s cyst treatment
In the Department of Orthopedics and Traumatology, surgical and conservative treatment of pathology is carried out. Conservative therapy consists in puncture of Baker’s cyst to remove inflammatory fluid and subsequent administration of corticosteroid drugs (for example, hydrocortisone) into the cavity of the interstitial bag. In parallel, the treatment of the underlying disease of the knee joint is carried out (therapy of rheumatoid arthritis, removal of the damaged part of the meniscus, etc.).
Surgical treatment of Baker’s cyst is indicated for its long-term existence, large size, compression of nerves, blood vessels and soft tissues, restriction of knee joint flexion and failure of conservative therapy. The operation is performed under local anesthesia. A small incision is made above the protrusion, the Baker’s cyst is isolated, the junction of the tendon bag with the knee joint is stitched and bandaged, after which the cyst is removed. In recent years, an arthroscope has often been used to remove Baker’s cyst, which reduces the traumatic nature of surgery.
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