Baker’s Cyst

Abstract

Context:Popliteal synovial cysts, also known as Baker’s cysts, are commonly found in association with intra-articular knee disorders, such as osteoarthritis and meniscus tears. Histologically, the cyst walls resemble synovial tissue with fibrosis evident, and there may be chronic nonspecific inflammation present. Osteocartilaginous loose bodies may also be found within the cyst, even if they are not seen in the knee joint. Baker’s cysts can be a source of posterior knee pain that persists despite surgical treatment of the intra-articular lesion, and they are routinely discovered on magnetic resonance imaging scans of the symptomatic knee. Symptoms related to a popliteal cyst origin are infrequent and may be related to size.Evidence Acquisition:A PubMed search was conducted with keywords related to the history, diagnosis, and treatment of Baker’s cysts—namely, Baker’s cyst, popliteal cyst, diagnosis, treatment, formation of popliteal cyst, surgical indications, and complications. Bibliographies from these references were also reviewed to identify related and pertinent literature.Study Design:Clinical review.Level of Evidence:Level 4.Results:Baker’s cysts are commonly found associated with intra-articular knee disorders. Proper diagnosis, examination, and treatment are paramount in alleviating the pain and discomfort associated with Baker’s cysts.Conclusion:A capsular opening to the semimembranosus–medial head gastrocnemius bursa is a commonly found normal anatomic variant. It is thought that this can lead to the formation of a popliteal cyst in the presence of chronic knee effusions as a result of intra-articular pathology. Management of symptomatic popliteal cysts is conservative. The intra-articular pathology should be first addressed by arthroscopy. If surgical excision later becomes necessary, a limited posteromedial approach is often employed. Other treatments, such as arthroscopic debridement and closure of the valvular mechanism, are not well studied and cannot yet be recommended.

Arthroscopic Treatment of Popliteal Cysts

“…Popliteal cysts are relatively common in patients over 50 years old. 3 , 4 Although there have been a few modifications of the description of these cysts, the popliteal cyst is best defined as an enlargement of the gastrocnemius-semimembranosus bursa, which communicates with the knee joint via a valve-like structure. 4 , 5 It is the presence of this valve-like structure that allows the cysts to be successfully treated via arthroscopic surgery.…”

A Rare Case of Juvenile Idiopathic Arthritis following a Ruptured Baker’s Cyst in a Toddler

“…A rupture within this communication causes fluid to drain down, resulting in calf swelling. In adults, the condition usually manifests with previous intra-articular conditions [3], whereas children may have no coexisting or previous knee pathology [4]. Other causes of chronic knee such as tendon pathologies, e.g., semimembranous tendinopathy, can present with a similar clinical picture [5].…”

Assessment of the Magnetic Resonance Imaging Features of Baker’s Cysts and Their Correlation with the Age of Patients

“…Нарастание внутрисуставного давления вследствие вторичного экссудативного синовита вызывает выдавливание суставной жидкости через слабое место заднемедиальной части суставной капсулы, находящееся между медиальной головкой икроножной и сухожилием полуперепончатой мышц, в икроножно-полуперепончатую бурсу [7]. Особенности строения соустья между суставным пространством и сумкой позволяют жидкости свободно течь только в одном направлении, что, в свою очередь, приводит к увеличению давления внутри кисты [8]. А повышенное давление, со своей стороны, способствует постепенному увеличению подколенной кисты и вероятным осложнениям заболевания в дальнейшем [9].…”

“…Компримирование проходящих рядом нервов может привести к соответствующим симптомам неврита, а сжатие подколенной артерии и вены -к ишемии или тромбозу глубоких вен соответственно [10][11][12]. Большие кисты могут механически ограничивать сгибание коленного сустава [8]. Поскольку подколенные кисты часто изменяют свой объем, в том числе под воздействием лечения, то и проявления этих повреждений могут иметь различную степень выраженности.…”