Ivanova Silviya, Rosenstock Piet, Leibold Christiane Sylvia, Vuillemin Nicolas, Keel Marius Jb, Egli Rainer J, Bastian Johannes D
Department of Orthopaedic Surgery and Traumatology, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland.
Institute of Diagnostic, Interventional and Pediatric Radiology, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland.
Injury. 2025 Aug;56(8):112459. doi: 10.1016/j.injury.2025.112459. Epub 2025 May 27.
The gull sign, representing superomedial dome impaction in acetabular fractures, was first described approximately 20 years ago by Anglen and co-workers. They concluded that this sign equates with poor outcomes after open reduction and internal fixation (ORIF), terming it a "harbinger for failure". Since then, the presence of the gull sign has frequently influenced surgical decision-making in geriatric acetabular fractures. The aim of this radiological descriptive study was to revisit the accuracy of the gull sign seen on pelvic radiographs in predicting dome impaction on computed tomography (CT).
In a retrospective study, conventional pelvic radiographs and CT scans of n = 201 patients (mean age±SD: 68±17y, 75 % male) with acetabular fractures treated surgically between 2009 and 2020 were analyzed. The presence of the gull sign was assessed on anteroposterior pelvic radiographs. CT scans were assessed for true impaction ("brick sign") with focus on the acetabular surface and compared to the findings according to Anglen`s description.
The gull sign was noted on pelvic radiographs in 49 of 201 cases (24 %). In 28 out of these 49 cases (57 %) a dome impaction was noted on CT. In the remaining 21 cases (43 %), CT revealed no actual impaction but rather an elevated dome following displaced fracture fragments. Conversely, among the 152 patients (76 %) without a gull sign, CT identified previously undetected dome impactions in 41 cases. Overall, the gull sign had a sensitivity of 41 %, a specificity of 84 %, and a positive predictive value of 57 % for detecting dome impactions.
The gull sign is an unreliable predictor for dome impaction in acetabular fractures for the following reasons: in the presence of the gull sign nearly half of the cases an elevated fragment only (not an impacted fragment) was noted on CT; despite an absence of the gull sign in nearly one-third of these cases dome impactions ("brick sign") were present on CT. Consequently, routine preoperative CT imaging is essential to accurately differentiate true dome impactions ("brick sign") from dome elevation, thereby guiding appropriate surgical decision-making between "disimpaction versus reduction" and in general between the "fix or replace" debate.
海鸥征代表髋臼骨折中的髋臼上内侧穹顶撞击，大约20年前由安格伦及其同事首次描述。他们得出结论，该征象等同于切开复位内固定（ORIF）术后预后不良，称其为“失败的预兆”。从那时起，海鸥征的出现经常影响老年髋臼骨折的手术决策。这项放射学描述性研究的目的是重新审视骨盆X线片上所见海鸥征在预测计算机断层扫描（CT）上的穹顶撞击方面的准确性。
在一项回顾性研究中，分析了2009年至2020年间接受手术治疗的201例髋臼骨折患者（平均年龄±标准差：68±17岁，75%为男性）的传统骨盆X线片和CT扫描。在骨盆前后位X线片上评估海鸥征的存在情况。对CT扫描进行评估，以确定真正的撞击（“砖征”），重点关注髋臼表面，并与根据安格伦描述的结果进行比较。
201例中有49例（24%）在骨盆X线片上发现海鸥征。在这49例中的28例（57%）中，CT上发现穹顶撞击。在其余21例（43%）中，CT显示没有实际撞击，而是骨折碎片移位后穹顶抬高。相反，在152例（76%）没有海鸥征的患者中，CT在41例中发现了先前未检测到的穹顶撞击。总体而言，海鸥征检测穹顶撞击的敏感性为41%，特异性为84%，阳性预测值为57%。
海鸥征是髋臼骨折穹顶撞击的不可靠预测指标，原因如下：在有海鸥征的病例中，近一半在CT上仅发现碎片抬高（而非撞击碎片）；尽管在近三分之一的这些病例中没有海鸥征，但CT上仍存在穹顶撞击（“砖征”）。因此，术前常规CT成像对于准确区分真正的穹顶撞击（“砖征”）和穹顶抬高至关重要，从而在“解除撞击与复位”之间以及总体上在“固定还是置换”的争论中指导适当的手术决策。
