Kendoff Daniel, Citak Musa, Gardner Michael, Kfuri Maurico, Thumes Barbara, Krettek Christian, Hüfner Tobias
Trauma Department, Hannover Medical School, Hannover 30625, Germany.
Foot Ankle Int. 2007 Nov;28(11):1165-71. doi: 10.3113/FAI.2007.1165.
Anatomic reconstruction of the posterior calcaneal facet after intra-articular fracture is one of the critical factors in achieving a good functional result. Intraoperative evaluation of fracture reduction and implant placement relies on direct view by standard fluoroscopy. We hypothesized that three-dimensional (3D) fluoroscopy is more accurate than conventional fluoroscopy, and equivalent to CT for determining fracture reduction and screw position in calcaneal fractures.
A Sanders type IIB fracture pattern was created in eight embalmed lower extremity cadaver specimens. First, the posterior facet was reduced with a step-off of 0 mm to 2 mm in 0.5-mm increments. All specimens had two dimensional (2D) fluoroscopy, 3D fluoroscopy with an Iso-C3D, and a CT scan. Next, screws were placed so they protruded into the subtalar and calcaneocuboid joint and through the medial wall. All specimens were imaged again. Three observers evaluated all imaging studies, and the sensitivities and specificities of each modality were determined.
Both the Iso-C3D and the CT were more specific for anatomic reduction (75% and 100%, respectively) than fluoroscopy (62%). For the malreduced trials, the Iso-C3D and CT were both 100% sensitive, and the sensitivity of fluoroscopy was 63% (p < 0.001 for both). For the intra-articular screws, the Iso-C3D and CT were accurate in all cases (sensitivities = 100%), and fluoroscopy was accurate in five of the eight trials for both joints (sensitivities = 63%). Finally, with screws protruding through the medial wall, the sensitivity of fluoroscopy was 25%, for the Iso-C3D 88% (p = 0.02), and for CT was 100% (p = 0.003).
Three-dimensional fluoroscopic imaging is more accurate than 2D fluoroscopy for detection of intra-articular incongruities and implant position and is similar to CT.
This new technology may be particularly useful in assessing calcaneal fractures and may lead to improved fracture reduction, less implant misplacement, and improved patient outcomes.
关节内跟骨后关节面的解剖重建是获得良好功能结果的关键因素之一。术中对骨折复位和植入物放置的评估依赖于标准荧光透视的直接观察。我们假设三维（3D）荧光透视比传统荧光透视更准确，并且在确定跟骨骨折的骨折复位和螺钉位置方面与CT相当。
在8个防腐处理的下肢尸体标本上制造Sanders IIB型骨折模型。首先，将后关节面以0毫米至2毫米的台阶差、0.5毫米的增量进行复位。所有标本均进行二维（2D）荧光透视、使用Iso-C3D的3D荧光透视以及CT扫描。接下来，置入螺钉使其突入距下关节和跟骰关节并穿过内侧壁。所有标本再次进行成像。三名观察者评估所有影像学检查，并确定每种检查方式的敏感性和特异性。
Iso-C3D和CT在解剖复位方面（分别为75%和100%）比荧光透视（62%）更具特异性。对于复位不良的试验，Iso-C3D和CT的敏感性均为100%，而荧光透视的敏感性为63%（两者p均<0.001）。对于关节内螺钉，Iso-C3D和CT在所有病例中均准确（敏感性=100%），荧光透视在两个关节的8次试验中有5次准确（敏感性=63%）。最后，对于穿过内侧壁的螺钉，荧光透视的敏感性为25%，Iso-C3D为88%（p=0.02），CT为100%（p=0.003）。
三维荧光透视成像在检测关节内不平整和植入物位置方面比二维荧光透视更准确，且与CT相似。
这项新技术在评估跟骨骨折方面可能特别有用，并可能导致骨折复位改善、植入物误置减少以及患者预后改善。
