Popliteal Cysts: A Current Review,Zhou Zhenghu formation,Abstract,Of the possible cystic lesions around the knee joint, popliteal cysts are the most prevalent.Popliteal cysts most commonly form by distention of the gastrocnemio-semimembranosus bursa, which is located in the medial aspect of the popliteal fossa.These cysts are also referred to as Bakers cysts, a name given to the condition after Bakers classic case description of popliteal swelling腘窩囊腫是膝關節周圍最常見的囊性病變。腘窩囊腫通常由腘窩內側的腓腸肌 - 半膜肌滑囊膨脹形成，最早由 Baker 報道，又稱 Bakers 囊腫。,Abstract,The gastrocnemio-semimembranosus bursa is situated between the tendons of the gastrocnemius and semimembranosus muscles and is a normal anatomic finding.腓腸肌 - 半膜肌滑囊是位于腓腸肌、半膜肌肌腱之間的正常解剖組織。,Abstract,This bursa has been found to communicate with the knee joint capsule via a transverse opening in the posterior capsule at the level of the medial femoral condyle, where the gastrocnemius tendon merges with the joint capsule.該滑囊通過一橫孔與膝關節囊腔相通，橫孔位于股骨內側髁水平處的關節囊后部。且腓腸肌肌腱與膝關節囊在股骨內側髁處相連。,Abstract,Most often, this opening takes the shape of a horizontal slit measuring 4 to 24 mm.The communication between the bursa and the joint capsule is almost nonexistent in children, and the presence of this opening increases in frequency with age.橫孔通常是 4 到 24 毫米大小的水平裂縫。滑膜囊腔通常在兒童階段并不與關節腔相通，隨著年齡的增加，出現缺口的幾率也增加。,Abstract,The integrity of the joint capsule decreases with age, and it is theorized that this opening results from a tear in the degenerated joint capsule. Rauschning observed that, when no opening was found, capsular thinning was seen in the same area and noted that the cyst is simply a herniation of synovium, as originally postulated by Baker.膝關節囊完整性隨著年齡增加而減低，有理論認為缺口是由于退化的膝關節囊撕裂后所致。Rauschning 觀察到，對無關節缺口的人群，在囊腫的同一區域仍可觀察到關節囊，提示腘窩囊腫可能是貝克最初假設的滑膜疝出所致。,Abstract,A true ganglion cyst can form, usually by fluid leakage through a horizontal or oblique medial meniscus tear, forming a wall of dense fibrous connective tissue (not synovium) as a distinguishing feature (Figure 1).真正腱鞘囊腫通常是液體從斜行或水平內側半月板裂隙滲出形成，其明顯的特征是形成厚厚的纖維連接組織壁（不是滑膜）（圖.1）。,Abstract,Abstract,The communication between the gastrocnemio-semimembranosus bursa and the joint capsule, which allows for the movement of synovial fluid between the 2 spaces, has been shown by arthrography. A valvelike mechanism that allows only unidirectional flow from the joint into the bursa has been found in some of these openings.關節造影術顯示，關節液在腓腸肌 - 半膜肌滑囊與膝關節囊互通的兩個腔隙之間運動。在有些互通缺口中發現類瓣膜機制，只允許關節液單方向流向滑囊。,Abstract,Intra-articular and intracystic pressure measurements have been made in the knees of patients with rheumatoid arthritis who have popliteal cysts，and in every case intracystic pressure was higher than intra-articular pressure.These findings of fluid accumulating in the popliteal cyst and not being able to leave, despite high pressure, indicate the presence of a 1-way valve-type mechanism.測量類風濕患者腘窩囊腫內壓和關節內壓發現，所有患者囊腫內壓高于關節內壓。這些發現提示，液體積聚在囊腫內，盡管內壓高，但并不流走，表明存在單向瓣膜機制。,Clinical Presentation,In children, a popliteal cyst is most often an incidental finding on physical examination. Occasionally a child or parent sees or feels a cyst and becomes concerned about the presence of a mass.兒童中，腘窩囊腫常在體檢中偶然發現。有時父母因腫塊（囊腫）發現囊腫。,Clinical Presentation,Typical adult clinical presentation is vague posterior knee pain, possible localized swelling or mass, and a feeling of tightness in the popliteal region. Physical examination may show a tender palpable mass in the medial popliteal fossa, although this finding is subjective and is somewhat dependent on the physicians opinion and experience。成人臨床常表現為膝后部隱約痛，局部腫脹及腫塊，腘窩區域緊張感。物理查體可以發現在內側腘窩可觸及柔軟腫塊。這還有賴于醫生主觀的經驗。,Clinical Presentation,Most cysts are found on the medial side of the posterior knee and are reported more rarely on the lateral side.The cyst is usually rounded, smooth, and fluctuant, and may feel tense in extension, but this is a difficult finding to quantify.This hardness of the cyst in full extension followed by softening with knee flexion is known as Fouchers sign囊腫在膝關節后內側，很少在外側，呈圓形，光滑，波動感，擴張時可能緊張，但是這很難量化。膝關節伸直時，囊腫變硬，屈曲時軟化，稱為 Foucher 征。,Clinical Presentation,Calf pain and swelling are also present in DVT or superficial thrombophlebitis, and the clinical imperative is to rule out DVT with appropriate diagnostic imaging studies.Pseudothrombophlebitis has the same clinical presentation as DVT or superficial thrombophlebitis, but is caused by another condition，such as a ruptured popliteal cyst.DVT 和表淺性血栓靜脈炎也會出現上述癥狀，因此影像學檢查排除 DVT 很有必要。假性血栓性靜脈炎臨床表現同 DVT 和表淺性血栓靜脈炎相同，比如破裂的腘窩囊腫就可以引起。,Clinical Presentation,Discoloration or ecchymosis in the calf, at the medial malleolus, or on the dorsum of the foot is a distinguishing feature of a ruptured cyst because bloody synovial cyst fluid dissects inferiorly.在小腿，內踝或是足背出現變色或是瘀斑是囊腫破裂的特異性特征。,Treatment of ruptured cysts typically involves treating resultant complications, but ruptured cysts without complications have been reported to resolve spontaneously with supportive conservative care, such as compression and elevation of the limb.囊腫破裂后治療通常是治療相應的并發癥，然而無并發癥的破裂囊腫在保守支持治療下可自行緩解，如抬高或加壓患肢。,Diagnostic Imaging,Multiple imaging techniques may be used in the diagnosis and assessment of a popliteal cyst.Plain radiographs are simple and readily available, but they provide limited information about the popliteal cyst. However, they may help in identifying associated articular disorders, such as loose bodies in the cyst or the general findings of osteoarthritis and inflammatory arthritis. 診斷和評估腘窩囊腫可采用多種影像學方法。平片簡單易行，僅能提供有限的信息。但有助于鑒別相關關節疾病，如囊內游離體，骨關節炎，關節炎。,Diagnostic Imaging,Other imaging techniques are often more suitable for diagnosing popliteal cysts. Previously, arthrography was commonly used in the imaging of popliteal cysts, but disadvantages such as the invasiveness of the procedure and the possibility of contrast extravasation have been made apparent.其他影像學方法更適于診斷腘窩囊腫。以前常采用關節造影術，但有如操作創傷性及造影劑可能外滲等缺點。,Diagnostic Imaging,Ultrasound quickly became a popular replacement for arthrography in imaging for the presence of popliteal cysts. Ultrasound is readily available, relatively inexpensive, and noninvasive, and it involves no exposure to radiation. 由于超聲簡單易行，相對便宜，非創傷性，無輻射，因此很快替代關節造影檢查。,Diagnostic Imaging,Ultrasound, however, is not sensitive to intra-articular lesions, and so further imaging is needed to confirm the presence of an associated internal derangement.然而超聲對關節內病變不敏感，因此需要進一步辨別相關關節內部疾病。,Diagnostic Imaging,Magnetic resonance imaging is considered the gold standard in the visualization and characterization of masses about the knee.A distinct advantage of MRI is the ability of axial images to visualize a fluid-filled neck of the cyst communicating with the joint (Figure 1).MRI 是鑒定膝關節周圍腫塊的金標準檢查。MRI 獨特的優點是軸向顯現囊腫與關節交通處充滿液體的頸部（圖.1）。,Diagnostic Imaging,Treatment and Outcomes,There are many treatment options for popliteal cysts, dictated by the underlying cause and associated condition. Sometimes no treatment or simple supportive measures result in spontaneous resolution of the cyst or at least reduction in associated symptoms. If not, both minimally invasive and surgical techniques are alternatives.治療腘窩囊腫的方法取決于潛在病因及相關疾病。有時不治療或簡單支持治療也可以緩解腘窩囊腫癥狀。若保守治療無效，微創或外科手術均可選擇。,Treatment and Outcomes,Ultrasound-guided aspiration with corticosteroid injection is a relatively low-risk and successful procedure for the treatment of knee osteoarthritis complicated with a popliteal cyst.Another option is a similar procedure in which corticosteroid is injected directly into the popliteal cyst. 超聲引導抽吸術并注射皮質激素治療膝關節炎并發腘窩囊腫是一個低風險和較成功的方法。另一相似方法是直接向腘窩囊腫內注射皮質激素。,Treatment and Outcomes,More recently, intra-articular corticosteroid injections were compared with intracystic corticosteroid injections in patients with knee osteoarthritis.Although both methods are suitable treatment options in patients with knee osteoarthritis, direct injection into the popliteal cyst may provide greater reduction in cyst size.最近，對關節內注射與囊內注射皮質激素治療效果進行了比較。雖然這兩種方法是治療膝關節骨性關節炎患者合適的治療方案，但是囊內直接注射會更大地減小囊腫尺寸。,Treatment and Outcomes,Although conservative and minimally invasive measures are available to treat some of the conditions associated with popliteal cysts, not all may improve without invasive intervention. Currently, arthroscopic procedures are most commonly used to treat the conditions associated with popliteal cysts and to address cysts directly. 盡管保守和微創治療適用于某些腘窩囊腫患者，但有些患者尚需手術干預。目前，關節鏡最常用于治療腘窩囊腫，直接處理囊腫。,Treatment and Outcomes,The primary goal of surgical intervention in symptomatic popliteal cysts is to resolve the underlying intra-articular pathology and reduce chronic effusion. Others believe that popliteal cysts are best treated by closing the communication to the cyst.手術治療的主要目標是解決潛在關節內病變及減少關節慢性滲出。也有一些學者認為，腘窩囊腫最好的治療方法是閉合囊腫與關節之間的交通。,Treatment and Outcomes,Patients were treated arthroscopically for meniscal tears, chondral lesions, or a combination. In addition to these procedures, an arthroscopic suturing technique via an accessory posteromedial working portal was performed to close the communication into the popliteal cyst (Figure 2).患者均采用關節鏡治療半月板撕裂，軟骨損傷，或兩者同時存在，經后內側入口關節鏡下縫合囊腫與關節交通處（圖.2）。,Treatment and Outcomes,圖.2 關節鏡下修復腘窩囊腫瓣膜開口。穿過可吸收縫線（A）, 使用探針鉤回縫線（B），打結關閉囊腫開口（C）。,Figure 2：Technique of arthroscopic repair of the valvular opening into a popliteal cyst. Passing of an absorbable suture (A). Retrieval of sutures with a hook probe (B). Final repair with knots closing the