貝克氏囊腫在痛風性關節炎中的盛行率：一超音波研究

The prevalence of Baker's cysts in patients with gouty arthritis: an ultrasonographic study

目的：研究貝克氏囊腫在痛風病人中的盛行率。方法︰回溯分析103位痛風性關節炎病患的臨床症狀與骨骼肌肉超音波發現，所有病患皆抽取關節液分析確認有尿酸結晶，並針對關節積液、滑膜炎、雙輪廓徵象（double-contour sign）、肌腱病變、痛風石與貝克氏囊腫的關係進行了分析，並且取150位退化性關節炎患者為對照組。結果︰經由超音波發現103位痛風病患其中有28位具有貝克氏囊腫（27.1%），而這當中僅10位（35.7%）是經由臨床診斷發現。其他超音波發現96.1%病患具有關節積液，其次為滑膜炎96.1%、雙輪廓徵象32.0%、肌腱病變4.9%、痛風石7.8%。統計上貝克氏囊腫與滑膜炎最具相關性（p<0.05）；其他現象關節積液、滑膜炎、雙輪廓徵象（double-contour sign）、肌腱病變、痛風石則未達統計上的差異。此外有這28位貝克氏囊腫的病患中，有2例發現貝克氏囊腫破裂。結論︰在痛風關節炎病患中，貝克氏囊腫是相當常見的且很容易被臨床所低估。在針對貝克氏囊腫相關併發症以及治療，骨骼肌肉超音波對於臨床醫師是相當實用的。

Background: To investigate the prevalence of Baker’s cysts (BCs) in patients with gouty arthritis of the knee using high-resolution musculoskeletal ultrasound (MSUS). To the best of our knowledge, this is the first report in the literature. Methods: We retrospectively reviewed clinical and MSUS data of 103 consecutive patients with gouty arthritis of the knee and 150 patients with knee osteoarthritis examined as a control group. They all had crystal confirmation of gout after joint aspiration. The correlation of the presence of BCs with the presence of joint effusion, synovitis, the double-contour sign, tendinopathy, and tophi was analyzed. Results: BCs were demonstrated by MSUS in 28 (27.1%) of the 103 patients. Only 10 (35.7%) of the 28 cysts had been clinically diagnosed. Joint effusion, synovitis, the double-contour sign, tendinopathy, and tophi were respectively detected in 96.1%, 77.6%, 32.0%, 4.9%, and 7.8% of knees. There was a significant correlation between the presence of BCs and synovitis (p<0.05). There was no significant correlation between the presence of BCs with effusion, the double-contour sign, tendinopathy, and tophi (p>0.05). Two ruptured BCs were observed. Conclusions: These results indicated that BCs are common in patients with gouty arthritis, and that they can easily escape clinical detection. Therefore, MSUS should be more widely employed by clinicians for diagnosis and treatment selection for BCs, which may sometimes be accompanied by significant morbidity, and thus help choose an appropriate treatment.