Acetabular fractures revisited: part 2, a new CT-based classification

OBJECTIVE: The objective of this investigation was to provide a new CT-based classification of acetabular fractures. MATERIALS AND METHODS: The axial CT scans of 112 randomly selected acetabular fractures in patients admitted to a level 1 trauma center between January 1998 and December 2000 were analyzed by an experienced orthopedic trauma surgeon and two experienced emergency radiologists. When available, 3D reformatted images were analyzed as well. The fracture pattern for each acetabular fracture, with respect to column walls and extension beyond the acetabulum, when present, was recorded. Fracture comminution was not a defining characteristic. RESULTS: Analysis of the 112 acetabular fracture patterns showed that each fracture fell into one of four broad categories. Category 0 included wall fractures only. Category I included acetabular fractures limited to a single (anterior or posterior) column. Category II fractures included those involving both the anterior and posterior columns; category II fractures were further subdivided into those with no fracture extension beyond the acetabulum, those with superior or inferior extension, and those with both superior and inferior extensions beyond the acetabulum. Category III fractures included only the "floating" acetabulum, which is defined as an acetabular fracture in which the acetabulum is separated from the axial skeleton both anteriorly and posteriorly. CONCLUSION: The axial CT display of acetabular fracture patterns provides a basis for a classification of acetabular fractures that is simple, unambiguous, readily understood by both radiologists and orthopedic surgeons and provides clear direction for both diagnosis and surgical treatment planning. Category and subcategory fracture specificity creates a mechanism for intra- and interdepartmental postoperative assessment of any of the individual acetabular fracture types.     

Classification of common acetabular fractures: radiographic and CT appearances

OBJECTIVE: Accurate characterization of acetabular fractures can be difficult because of the complex acetabular anatomy and the many fracture patterns. In this article, the five most common acetabular fractures are reviewed: both-column, T-shaped, transverse, transverse with posterior wall, and isolated posterior wall. Fracture patterns on radiography are correlated with CT, including multiplanar reconstruction and 3D surface rendering. CONCLUSION: In the evaluation of the five most common acetabular fractures, assessment of the obturator ring, followed by the iliopectineal and ilioischial lines and iliac wing, for fracture allows accurate classification. CT is helpful in understanding the various fracture patterns.     

Radiologic diagnosis of acetabular fractures

Acetabular fractures are caused by high kinetic energy, and satisfactory management requires differentiation of the fracture types. The basic radiological examinations consist of the A-P pelvic view, the obturator, and the iliac oblique view. Plain radiography proves to be insufficient, particularly for visualization of the posterior column and the posterior acetabular lip. In comparison, axial CT scans give exact and complete information about the acetabular fracture and associated injuries. In summary CT is the method of choice in evaluating dislocated or non-dislocated fractures, even when two- and three-dimensional reformation is involved.     

The effect of computed tomographic scan orientation on information loss in the three-dimensional reconstruction of tripod zygomatic fractures

Fractures modeled in the dried skull indicate that the initial plane of computed tomography (CT) section contributes to the accuracy of three-dimensional (3D) images generated from two-dimensional (2D) CT data. The authors retrospectively analyzed seven clinical cases of tripod zygomatic fractures that were imaged with both axial and coronal CT scan orientations. Ten observers evaluated paired 3D CT images, one generated from 2D CT data in the axial plane and the other generated from coronal 2D CT data, for each of the seven cases of tripod fractures. A G-E 9800 CT scanner with the 3D98 Quick processing system were used for the 3D reconstructions. The axial scan orientation resulted in 3D reconstructions that had significantly less information loss in the display of the tripod fractures than did those based on coronal CT data (P less than .025).     

Acetabular fractures revisited: a new CT-based classification

The objective of this investigation is to provide a new CT-based classification of acetabular fractures. The axial CT scans of 112 randomly selected acetabular fracture patients admitted to a Level 1 trauma center between January 1998 and December 2000 were analyzed by an experienced orthopedic trauma surgeon and two experienced emergency radiologists. When available, 3D reformatted images were analyzed as well. The fracture pattern for each acetabular fracture with respect to column(s) wall(s) and extension superiorly and/or inferiorly from the acetabulum, when present, was recorded. Fracture comminution was not a defining characteristic. Analysis of the acetabular fracture patterns showed that each fracture fell into one of four broad categories: Category 0--wall only; Category 1--single column; Category 2--both columns, with extension subcategories of (A) no extension, (B) superior extension only, (C) inferior extension only, and (D) both superior and inferior extension; and Category 3--the "floating" acetabulum. The axial CT display of acetabular fracture patterns provides a basis for a classification of acetabular fractures that is simple, unambiguous, readily understood by both radiologists and orthopedic surgeons, and provides clear direction for both diagnosis and surgical treatment planning. Category and subcategory fracture specificity creates a mechanism for intra- and interdepartmental postoperative assessment of any of the individual acetabular fracture types.     

The role of 3D CT in the assessment of acetabular fractures.

A total of 16 patients with acetabular fractures were evaluated by plain radiography, axial computed tomography (CT) and three dimensional (3D) CT. It was possible to classify the fracture type in each case from the plain radiographs alone. Axial CT gave additional detail in certain areas, notably the region of the teardrop, the obturator foramen and the acetabular roof. Intra-articular and impacted roof fragments and associated soft tissue injuries were also shown. 3D CT provided the best and most easily interpreted overall assessment of the fractures. In addition to projections equivalent to the plain radiographs, two other views were of particular clinical value in demonstrating surgically inaccessible areas, namely the view of the pelvis from above and the view of the inner aspect of the fractured hemipelvis. However, fracture lines demonstrated on plain radiographs and axial CT were not always apparent on the 3D CT scans. Although 3D CT is a valuable addition to the imaging of acetabular fractures, it is not a substitute for good quality plain radiography and analysis of the axial CT images.     

螺旋CT三维和多平面重建在髋臼骨折中的应用

目的：探讨螺旋CT三维（3D）和多平面重建（MPR）在髋臼骨折中的临床应用价值。方法：27例髋臼骨折的病人先经营骨盆螺旋CT薄层扫描，并在工作站上作髋臼三维和多平面重建。注重观察髋臼骨折的以及CT表现特征。结果：27例病人共计31个髋臼骨折。除1个T形骨折用三维和多平面重建判断为横行骨折外，其余30个骨折轴位CT、三给和多平面重建均显示。三维和多平面重建能更直观的显示病变的具体情况。结论“螺旋CT三维和多平面重建是轴位CT扫描的有价值的补充手段，在髋臼骨折中有很高的应用价值。     

Three-dimensional computed tomography of the acetabulum

Acetabular fractures represent a complex variety that are classified in different types. Conventional radiology is often inadequate to demonstrate and classify the fractures. Computed tomography (CT) has already been shown to be superior in this field. A further advantage of CT is represented by the recent availability of three-dimensional (3D) images that are realized from axial CT scans by means of a new software. The Authors report the applications of this new software to the study of the normal acetabulum and in patients with fractures. 3D images allows an effective demonstration of the fracture, its irradiation and the dislocation of bone fragments. The information is contained in one or few images rather than many axial images. Therefore the role of 3D images may be considered complementary to axial CT scans.     

Ⅰ期全髋关节置换治疗髋臼骨折

目的 探讨髋臼骨折后Ⅰ期全髋关节置换(total hip arthroplasty,THA)的手术适应证和手术方法,观察其临床疗效.方法 对11例髋臼骨折患者行Ⅰ期THA.其中前柱骨折3例,后壁骨折1例,后柱骨折2例,后柱合并后壁骨折2例,横形骨折1例,横形合并后壁骨折1例,两柱骨折1例.伤后8～37 d(平均24 d)接受THA.对新鲜髋臼骨折患者,先用重建钢板或螺钉固定骨折以恢复髋臼肇的形态,将切下的股骨头制成颗粒状或块状植于髋臼内后安置臼杯.陈旧性髋臼骨折有节段性髋臼骨缺损者,将切下的股骨头制成大块状进行髋臼内结构性植骨后再安置臼杯.结果 术后3个月完全负重,无人工关节脱位.随访时间6～45个月,平均28个月.Harris评分平均78分.髋关节屈伸平均活动度为95°.X线片示1例出现髋臼松动及骨溶解征象.结论 髋臼骨折移位明显,关节软骨面损伤严重,错过了手术复位时机,可以Ⅰ期行THA.如能创造稳定的髋臼杯结构,近期临床效果满意.     

髋臼骨折CT与X线平片检查比较

目的探讨CT与X线平片检查在髋臼骨折诊断中的临床应用价值。方法对照分析18例髋臼骨折CT、X线平片及临床治疗随访资料。结果18例髋臼骨折中前壁骨折4例,前柱骨折4例,后壁骨折2例,后柱骨折2例,复杂骨折6例。伴有盆腔内软组织肿胀11例。其中X线平片误漏诊4例。CT检出骨碎片27块,X线平片检出12块,其中关节腔内游离骨碎片CT检出17块,X线平片检出4块。股骨头脱位7例,伴股骨头骨折3例,其中X线平片漏诊1例。结论CT显示关节腔内碎骨片,确定骨折分型及了解盆腔软组织受损情况优于X线平片检查。     

Utility of roof arc measurements in acetabular fractures

For patients with acetabular fractures, the extent to which a fracture involves the weight-bearing dome has been estimated with the “roof arc” measurement obtained on radiographs and computed tomographic (CT) studies. We present the method for measuring the roof arc on radiographs and estimating this arc on CT scans. We also studied the utility of these roof arc measurements for predicting surgical vs. conservative management. Thirty-five patients with transverse or T-shaped acetabular fractures were reviewed. Roof arc measurements were performed on radiographs and CT scans. The clinical record for each patient was reviewed to determine whether the patient had been treated conservatively or surgically. Patients treated operatively for their acetabular fractures had a smaller roof arc measurement, as measured on radiographs, when compared to those patients treated nonoperatively. CT estimation of the roof arc measurement also was different between the two groups. We conclude that roof arc measurements are useful to further characterize patients with acetabular fractures.     

Diagnostic value of 3 D CT surface reconstruction in spinal fractures

Our purpose was to evaluate the diagnostic value of three-dimensional (3 D) CT surface reconstruction in spinal fractures in comparison with axial and reformatted images. A total of 50 patients with different CT-proven spinal fractures were analysed retrospectively. Based on axial scans and reformatted images, the spinal fractures were classified according to several classifications as Magerl for the thoraco-lumbar and lower cervical spine by one radiologist. Another radiologist performed 3 D CT surface reconstructions with the aim of characterizing the different types of spinal fractures. A third radiologist classified the 3 D CT surface reconstruction according to the Magerl classification. The results of the blinded reading process were compared. It was checked to see in which type and subgroup 3 D surface reconstructions were helpful. Readers one and two obtained the same results in the classification. The 3 D surface reconstruction did not yield any additional diagnostic information concerning type A and B injuries. Indeed, the full extent of the fracture could be easier recognized with axial and reformatted images in all cases. In 10 cases of C injuries, the dislocation of parts of vertebrae could be better recognized with the help of 3 D reconstructions. A 3 D CT surface reconstruction is only useful in rotational and shear vertebral injuries (Magerl type C injury). Received: 29 May 1995; Accepted: 11 January 1996     

Three-dimensional CT in the diagnosis of spinal trauma: comparison with plain film and two-dimensional CT examinations

To assess the value of three-dimensional (3D) image reconstructions of two-dimensional (2D) data from contiguous non-overlapping slices in the diagnosis of spinal trauma, 21 patients with a total of 36 injured vertebrae and 4 normal controls were examined. Forty plain films in two planes, 40 axial CT scans with multiplanar reformatted (MPR) 2D reconstructions and 40 sets of 3D images (surface rendering technique) were independently evaluated by four readers. The final diagnosis was defined after a panel review of clinical, surgical and imaging findings on all modalities. The 3D image reconstructions were not as accurate as axial CT with MPR 2D reconstructions in the diagnosis of vertebral body (n = 20) and posterior element fractures (n = 35). Dislocation (n = 3) was equally well detected by all imaging modalities. Narrowing of the spinal canal (n = 17) was best assessed by either MPR 2D CT or 3D images. A rotational component was diagnosed more accurately by 3D images, followed by 2D CT and plain films. Thus, 3D images combined with MPR 2D CT reconstructions are an important adjunct for an accurate diagnosis of spinal trauma, especially when a rotational component is suspected.Presented at the 1993 ECR Scientific Assembly Correspondence to: C. H. Buitrago-Téllez     

Computed tomography in acetabular trauma

In a retrospective study of 16 acetabular fractures computed tomography (CT) clarified the type and extent of the injury. Computed tomography demonstrated intra-articular fragments of varying size in seven out of eight patients with fractures of the posterior acetabular margin. Abnormalities of the femoral head were also shown in six patients and the possible aetiology of these is discussed. The additional information provided by CT is likely to help in the management of patients with acetabular injuries.     

Post-traumatic orbit evaluation by three-dimensional surface reconstructions

Post-traumatic orbital osseous and soft tissue surface evaluation was performed using high resolution computerized tomography and three-dimensional surface reconstructions (3DSR) using specially developed computer software. Four patients with facial fractures involving the orbit are presented as examples of the technique. Orbital volume was measured and surface images prepared using the original CT scans as input to CT computer software developed for this purpose. The results simplify interpretation of the nature and extent of traumatic orbital disruption. The interpretation of serial high resolution CT scans of the orbit (now obtained routinely in fractures involving the orbit) has been augmented by employing three-dimensional surface reconstructions (3DSR).     

3D CT versus axial helical CT versus conventional tomography in the classification of acetabular fractures: a ROC analysis

AIM: To assess the diagnostic power of three-dimensional computed tomography (3D CT), axial helical computed tomography (CT) and conventional tomography in the classification of acetabular fractures by interdisciplinary review. MATERIALS AND METHODS: Receiver operating characteristics (ROCs) were assessed for two radiologists and two surgeons blinded to the presence of acetabular fractures in an animal model (a total of 62 porcine hips, 40 of them with artificial acetabular fractures). Main target parameter was the diagnostic accuracy in the classification of the artificial fractures following Judet et al. RESULTS: ROC analysis for radiologists showed A(z) values of 0.83 for 3D CT, 0.81 for axial helical CT, and 0.78 for conventional tomography; differences between the three techniques were not significant (P = 0.46-0.73). A(z) values for the surgeons were 0.87 for 3D CT, 0.68 for axial helical CT, and 0.60 for conventional tomography; 3D CT was significantly better than axial helical CT (P = 0.01) and conventional tomography (P = 0.001). The differences between axial helical CT and conventional tomography were not significant (P = 0.37). CONCLUSION: Acetabular fractures are best classified by 3D CT, followed by axial helical CT and conventional tomography when assessed by surgeons. 3D CT did not provide any additional significant benefit in the classification performed by radiologists.     

Frontal sinus fractures: evaluation of CT scans in 132 patients.

PURPOSE: To determine the frequency of detection of frontal sinus fractures on initial CT scans of patients with intracranial injuries, and to characterize associated injuries. METHODS: The initial head CT scans in 132 patients with clinical or radiographic evidence of a frontal sinus fracture were retrospectively reviewed to further characterize the fracture. Additional radiographic studies and medical records were reviewed to determine associated injuries, therapy, clinical outcome, and complications. RESULTS: In 90% (124) of the patients, the frontal sinus fractures were visualized on initial head CT scans that were obtained to evaluate suspected intracranial injury. Complex fractures involving both the anterior and posterior wall of the sinus accounted for 65% of cases (86 patients), whereas fractures of the anterior wall only or posterior wall only occurred in 24% (32) and 11% (14) of patients, respectively. Significant intracranial hemorrhage occurred in over 90% of patients with fractures involving the posterior wall. CONCLUSIONS: In general, fractures that involved the posterior wall had more complications and a worse clinical outcome than fractures that only involved the anterior wall; nearly all frontal sinus fractures can be detected on head CT studies in patients with intracranial injuries.     

髋臼骨折的CT与X线平片诊断比较

目的:比较CT与X线平片对髋臼诊断的价值。材料和方法:18例髋臼骨折病人,全部接受CT扫描确诊,其中,14例是先经X线平片诊断为骨折的,4例X线检查未发现骨折线。分析比较CT与X线平片的表现。结果:经CT扫描发现的5例后壁骨折,X线漏诊2例;1例股骨头前缘皮质凹陷骨折、7例髋臼腔内游离碎片和10例髋关节周围软组织肿胀,X线均未能发现。结论:CT可准确显示骨折线的数目和走行方向,显示骨折类型和关节面损伤程度,以及关节腔内有无骨折碎片等情况,为临床治疗提供比X线平片更可靠的信息。     

Imaging manifestations of spinal fractures in ankylosing spondylitis

BACKGROUND AND PURPOSE: Spinal fractures in ankylosing spondylitis (AS) were difficult to diagnose before CT and MR imaging were available. The purpose of our investigation was to characterize spinal fractures and determine the value of different imaging modalities in AS. METHODS: Twelve successive cases of spinal fractures were identified in MR imaging files of AS patients. Conventional radiographs were available for 12, CT scans for 7, and 3D-CT scans for 4. We carefully reviewed clinical histories and imaging presentations. RESULTS: Fractures were found in the cervical spine in 3 patients and in the thoracolumbar spine in 9. The 3 columns of the spine were involved in 11 patients. A routine 4-mm axial CT was not enough to demonstrate all fractures and ligament tears. The sensitivities of 3D-CT scans for demonstration of the following problems were similar to that of MR imaging and were better than that of conventional radiographs: tearing of the posterior longitudinal ligament, the thoracic spinous process fracture, and the facet fracture. MR imaging depicted these following findings that usually were not shown on conventional radiographs or 3D-CT scans: cord deformity, soft tissue disruption, and ligament tears in the posterior column. MR imaging also showed avascular necrosis and occult fractures better than conventional radiographs or CT scans. CONCLUSIONS: MR imaging shows abnormalities in AS that may not be clear or even detectable by using other imaging methods. With the capability to show lesions in the posterior column, MR imaging can serve to evaluate AS patients with spinal fracture for the possibility of 3-column involvement.