貝克囊腫之臨床表現及其病因之探討

The etiology and clinical manifestation of Baker's cyst: a musculoskeletal ultrasound study

Purpose: Patients with rheumatic disease have a higher risk of developing Baker’s cysts. The aim of thisstudy is to determine the etiology of a Baker’s cyst and clinical manifestation.Method and Material: This is a retrospective review study using the musculoskeletal ultrasonography(MUS) database from June 2006 to June 2010. The relationship between the etiology of a Baker’s cystand its clinical manifestation, including gender, size of cyst, symptoms, physical examination, andcomplication, were analyzed using Pearson correlation coefficient, Student’s t test, one-way ANOVA andmultiple logistic regression.Results: We identified 301 Baker’s cysts in 257 patients. The prevalence of bilateral cysts was 5.9–27.3%across its different etiologies. We found that the most common cause of Baker's cyst was osteoarthritis(53.5%), while the most common cause of a ruptured Baker’s cyst was Rheumatoid Arthritis (RA) inwomen (47%) and gout in men (35%). Both grading of effusion and Kellgren and Lawrence(KL) gradewere positive related to the size of a Baker’s cyst. The mean size of palpable cyst was 7.95±0.53 cm andthat of non-palpable cyst was 2.65±0.11 cm (p<0.001). The size of Baker’s cyst (cm) was correlated withcyst rupture with odds ratio (OR): 2.58, confidence interval (CI): 1.69-3.95 (p<0.001).Conclusion: The etiology of a Baker’s cyst was different between the sexes. For early detection, MUSshould be performed in patients with advanced KL grade or knee effusions. In addition, patients with aBaker’s cyst on one knee, an imaging study should be performed on the contralateral side. 目的：風濕性疾病患者得到貝克氏囊腫的風險較高。這項研究的目的是為了瞭解貝克囊腫的病因和其臨床表現之關聯性。方法：這是一項回顧性研究，使用2006年6月至2010年6月的肌肉骨骼超音波資料庫。分析了貝克氏囊腫的病因與臨床表現（包括性別，症狀，身體檢查，囊腫大小和併發症）統計資料分析使用Pearson相關係數，Student'st檢驗，one-way ANOVA和多因素回歸測試。結果：我們在257名患者中發現了301個貝克氏囊腫。不同病因造成之雙側膝蓋囊腫之患病率為5.9－27.3％。我們發現造成貝克氏囊腫最常見的原因是退化性關節炎（53.5％），而貝克氏囊腫破裂的最常見原因於女性是類風濕性關節炎（47％）於男性則是痛風（35％）。關節積液分級，Kellgren and Lawrence（KL）分級均與貝克氏囊腫大小呈正相關。可摸到的囊腫的平均大小為7.95±0.53公分，摸不到的囊腫的平均大小為2.65±0.11公分（p<0.001）。貝克氏囊腫的大小（公分）與囊腫破裂呈正相關，Odds Ratio為：2.58，信賴區間（CI）：1.69－3.95（p<0.001）結論：引發貝克氏囊腫的病因在兩性之間是不同的。骨骼肌肉超音波應用在患有較嚴重的KL grade或膝關節積液的患者有助於早期診斷貝克氏囊腫，而如果病人在一側膝蓋發現貝克氏囊腫，則應在其對側膝蓋進行影像學檢查。