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.     

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.     

Nasofrontal duct: CT in frontal sinus trauma

Radiologic evaluation of frontal sinus fractures is instrumental in determining the need for surgery. Computed tomography (CT) is an excellent modality for evaluation of frontal sinus trauma, particularly for anterior and posterior wall fractures. However, fractures of the nasofrontal duct are more difficult to delineate, and judgments about operating for this problem are often made on less than concrete evidence of duct trauma. To evaluate the usefulness of CT in identifying nasofrontal duct trauma, a two-part study was done. First, CT was performed on cadavers to study the anatomic relationship of the nasofrontal duct to midface anatomy. Then, a retrospective study was performed in 19 patients with suspected frontal sinus fractures who underwent frontal sinus surgery. Findings at surgery were compared with preoperative evaluation with CT. Correlations were identified and criteria developed that can be used to identify patients needing surgical intervention in frontal sinus trauma. These criteria include findings of either a fracture involving the base of the frontal sinus or a fracture of the anterior ethmoid complex, or both.     

The role of imaging in the diagnosis and management of thoracolumbar burst fractures: current concepts and a review of the literature

 The burst fracture of the spine was first described by Holdsworth in 1963 and redefined by Denis in 1983 as being a fracture of the anterior and middle columns of the spine with or without an associated posterior column fracture. This injury has received much attention in the literature as regards its radiological diagnosis and also its clinical managment. The purpose of this article is to review the way that imaging has been used both to diagnose the injury and to guide management. Current concepts of the stability of this fracture are presented and our experience in the use of magnetic resonance imaging in deciding treatment options is discussed.     

外伤性胸腰椎骨折的X线和CT诊断

目的探讨X线和CT在外伤性胸腰椎骨折中的诊断价值。材料和方法57例胸腰椎骨折均行X线和CT检查。结果57例74个椎体骨折中单椎体骨折43例,多椎体骨折14例。爆裂型骨折45个椎体,压缩型骨折21个椎体,骨折脱位型9个椎体。骨折发生于前柱10个椎体,前中柱22个椎体,前中后柱39个椎体,中后柱2个椎体,前后柱1个椎体。结论X线平片对外伤性胸腰椎骨折有一定的价值,但CT在显示椎体三柱结构,骨折线,小关节脱位,椎管狭窄程度,脊柱稳定性,判断脊髓损伤等有明显优势。     

Avulsion fracture of the head of the fibula (the "arcuate" sign): MR imaging findings predictive of injuries to the posterolateral ligaments and posterior cruciate ligament

OBJECTIVE: The purpose of this study was to describe the significance of an avulsion fracture of the head of the fibula ("arcuate" sign) and its association with injuries of the knee on MR imaging. MATERIALS AND METHODS: We conducted a retrospective search of 2318 patients who underwent conventional radiography and MR imaging after an episode of knee trauma. Patients were included in this study if they had an avulsion fracture of the head of the fibula revealed on conventional radiography and underwent arthroscopy. Thirteen patients, all of whom were men, satisfied the inclusion criteria. Ten patients underwent further explorative surgery. The clinical, radiographic, MR imaging, and surgical findings were then reviewed. RESULTS: The avulsion fracture of the styloid process of the fibular head was apparently related to injuries of the arcuate complex in all 13 patients. Radiographically, the bony fragment was horizontally oriented and similar in size in most patients, ranging from 8 to 10 mm in length and from 2 to 5 mm in width. On MR imaging, the fibular avulsion was identified in 11 of the 13 patients. The other two patients had marrow edema in the fibular styloid process, although the avulsion fracture was not evident. All patients had injuries of the posterior cruciate ligament (six tibial avulsions, seven midsubstance tears). No patient had a tear of the anterior cruciate ligament. Disruption of the lateral collateral ligament was evident in seven patients, and one patient had a tear of the popliteal tendon. During surgery, six patients had disruption of the arcuate complex, but this disruption could not be identified on the MR images. CONCLUSION: An avulsion fracture of the fibular head generally involves the styloid process and causes injury of some of the major stabilizers in the posterolateral corner. Avulsion fractures are strongly associated with disruption of the posterior cruciate ligament.     

手术治疗髋臼骨折34例临床分析

目的：探讨髋臼骨折的手术方法和观察临床效果。方法：对2005-06～2010-06间共手术治疗髋臼骨折34例,采用Kocher-Langenbeck入路和髂腹股沟入路进行回顾性分析。结果：解剖复位28例,复位满意4例,复位不满意2例。全部病例获随访6～27月,平均10.2月,临床效果优良率为94.12%（32/34）。结论：手术是治疗髋臼骨折的有效方法,正确的手术入路选择、骨折解剖复位、稳定的内固定及早期功能锻炼是治疗的关键。     

Spatial relationship between intrahepatic artery and portal vein based on the fusion image of CT-arterial portography (CTAP) and CT-angiography (CTA): new classification for hepatic artery at hepatic hilum and the segmentation of right anterior section of the liver

Purpose

To clarify the variations of the intrahepatic artery and portal vein and to verify the proper segmentation for the right anterior section of the liver.

Materials and methods

CT during arterial portography and CT angiography were performed on 64-slice multi detector row CT in 147 patients. All images were transferred to a workstation for analysis using multi-image-fusion mode. We investigated the spatial relationship between hepatic artery and portal vein in the right hemiliver and the segmentation of the right anterior hepatic artery and portal vein.

Results

The spatial anatomy of right hepatic arteries and portal vein was (1) anterior and posterior hepatic artery run superior and inferior to anterior portal vein, respectively (47.6%), (2) one anterior hepatic artery runs superior to and another one runs inferior to anterior portal vein (15%), (3) anterior and posterior hepatic arteries run superior to anterior portal vein (11.6%), (4) anterior and posterior hepatic arteries run inferior to anterior portal vein (7.5%), and (5) one posterior hepatic artery runs superior to and another one runs inferior to anterior portal vein (6.8%).The combined anatomy of right anterior artery and portal vein with regard to segmentation was classified as (1) dorso-ventral (26.5%), (2) dorso-ventral and inferior (10.9%), (3) multiple (18.4%), and (4) superior and inferior segments (1.4%).

Conclusion

There are various types of spatial anatomy of intrahepatic artery and portal vein. The hepatic arteries as well as portal veins of right anterior section of the liver could be divided into dorsal and ventral, not superior and inferior.     

复合髋臼骨折手术中后方入路的特点和选择

目的探讨后方入路(Kocher-Langenbeck,K-L)在治疗复合髋臼骨折中的特点和选择指征。方法自1994年10月～2010年1月,通过后方入路手术治疗59例复合髋臼骨折,对患者手术过程、术后复位情况和并发症进行随访评价。结果平均手术时间105分钟,平均出血量480m l,平均输血2U;解剖复位31例,良好复位17例,复位差11例;发生异位骨化11例。结论在复合髋臼骨折中,后柱+后壁、横断+后壁、部分T型和前方伴后方横形骨折,甚至少量双柱骨折可经后方入路完成复位和固定,手术创伤小,复位情况良好,并发症发生率低。     

Greater trochanter of the hip: attachment of the abductor mechanism and a complex of three bursae--MR imaging and MR bursography in cadavers and MR imaging in asymptomatic volunteers.

PURPOSE: To evaluate trochanteric anatomy with magnetic resonance (MR) imaging, bursography, MR bursography, and anatomic analysis. MATERIALS AND METHODS: T1-weighted and fat-saturated T2-weighted (transverse, sagittal, coronal, and coronal oblique planes) MR imaging of the greater trochanter was performed in 10 cadaveric hips and 12 hips of asymptomatic volunteers. Three bursae comprising the trochanteric bursa complex were injected, and conventional radiography and MR imaging were performed. The specimens were sectioned for anatomic analysis, corresponding to the MR imaging planes. Tendon attachments and bursal localization were related to the facets of the greater trochanter. RESULTS: The bony surface of the greater trochanter consists of four facets: anterior, lateral, posterior, and superoposterior. The gluteus medius muscle attaches to the superoposterior and lateral facets. The gluteus minimus muscle attaches to the anterior facet. The trochanteric bursa covered the posterior facet and the lateral insertion of the gluteus medius muscle. The subgluteus medius bursa was located in the superior part of the lateral facet, underneath the gluteus medius tendon. The subgluteus minimus bursa lies in the area of the anterior facet, underneath the gluteus minimus tendon, medial and cranial to its insertion, and extends medially covering the distal anterior part of the hip joint capsule. The trochanteric bursa is delineated with fat on both sides and can be seen on transverse nonenhanced T1-weighted images as a fine line curving around the posterior part of the trochanter. CONCLUSION: MR imaging and bursography provide detailed information about the anatomy of tendinous attachments of the abductor muscles and the bursal complex of the greater trochanter.     

The insula: anatomic study and MR imaging display at 1.5 T

BACKGROUND AND PURPOSE: The insula is important for gustatory sensation, motor speech control, vestibular function, and sympathetic control of cardiovascular tone. The purpose of this study was to test two hypotheses: 1) gross anatomic study of the insula will disclose reproducible patterns of insular structure, and 2) analysis of MR appearance will enable physicians to recognize these patterns on imaging studies. METHODS: Gross insular anatomy was determined in 16 normal human cadaveric hemispheres. The 1.5-T MR images of 300 insulae were analyzed to determine the gyral and sulcal patterns displayed; their relationship to the Heschl gyrus, to the overlying opercula, and to the vertical planes perpendicular to the Talairach-Tournoux baseline at the anterior commissure (VAC) and posterior commissure (VPC); their continuity into the orbitofrontal cortex; and appropriate landmarks for the anterior border, apex, and posterior border of the insula. RESULTS: MR images displayed the central sulcus of the insula (97%); the anterior (99%), middle (78%), and posterior (98%) short insular gyri that converge to the apex (100%) anteriorly; and the anterior (99%) and posterior (58%) long insular gyri posteriorly. The middle short gyrus was often hypoplastic (33%). The anterior intersections of the internal and external capsules typically delimit the anterior insular border (87%). VAC intersects the anterior insula (99%), usually at the precentral sulcus. The Heschl gyrus circumscribes the posteroinferior insula (100%). VPC demarcates the posterior insular border (94%). CONCLUSION: The two hypotheses were proved correct. The insula shows reproducible patterns of gross anatomy that are demonstrable on routine clinical MR images obtained at 1.5 T.     

髋臼骨折合并股神经损伤相关因素分析

目的 分析髋臼骨折合并股神经损伤的原因，以期进一步提高临床诊治水平。方法 1996年1月-2004年11月，共手术治疗髋臼骨折146例，其中6例合并股神经损伤，根据临床表现、CT及三维重建分析股神经损伤的原因。按Letournel和Judet的髋臼骨折分类法进行分类，双柱骨折2例，横形伴后壁骨折1例，因骨折形成的巨大血肿压迫股神经，致股神经损伤；前壁骨折伴股骨头前脱位1例，髋臼前柱陈旧性骨折合并耻骨上支骨折1例，骨折端直接挫伤股神经；前柱骨折合并髂骨翼骨折1例，因术中牵拉损伤股神经。5例患者给予血肿清除、神经束减压、神经外膜松解去除病因，1例行保守治疗。结果本组6例患者随访1—3年，平均随访1．8年。5例患者股四头肌肌力从术前1—2级恢复至4—5级，1例从伤后2—3级恢复至5级，伸膝功能正常，可正常行走。4例患者感觉功能完全恢复，1例患者随访2年后仍有大腿下2／3前方及小腿内侧感觉减退；另有1例牵拉伤患者肌力恢复正常，随访1．2年后仍存在感觉障碍。结论 髋臼骨折合并股神经损伤临床上少见，复杂髋臼骨折应高度警惕有无股神经损伤；髂腰肌周围血肿形成及骨折块直接损伤是髋臼骨折合并股神经损伤的常见原因；医源性损伤需引起重视。     

MR imaging,MR arthrography,and specimen correlation of the posterolateral corner of the knee: an anatomic study

OBJECTIVE: We sought to evaluate the anatomy of the posterolateral aspect of the knee with anatomic dissection, MR imaging, MR arthrography, and sectional anatomy. MATERIALS AND METHODS: We assessed the posterolateral corner of the knee during dissection of one gross anatomic specimen. MR imaging and MR arthrography were performed in seven additional knee specimens. T1-weighted spin-echo MR images were obtained in the standard imaging planes as well as in the coronal oblique plane. The specimens underwent T1-weighted spin-echo MR imaging after administration of intraarticular contrast material and were sectioned into planes corresponding to those of the MR images. RESULTS: At anatomic dissection, the following posterolateral structures were identified: the arcuate ligament (medial and lateral limbs), fabellofibular ligament, popliteofibular ligament, popliteus tendon and its two posterior attachments to the lateral meniscus, fibular collateral ligament, direct and anterior arms of the tendon of the long head of the biceps femoris muscle, and direct and anterior arms of the tendon of the short head of the biceps femoris muscle. Correlation of MR imaging and anatomic findings showed that the popliteofibular ligament and oblique popliteal ligament were found in 57% and 100% of specimens, respectively. At least one of the two limbs of the arcuate ligament was identified in 71% of specimens. The fabellofibular ligament was not identified on MR images in any of the specimens. The anteroinferior and posterosuperior popliteomeniscal fascicles were identified in all specimens. CONCLUSION: The posterolateral corner of the knee comprises complex and variable anatomic structures. Recognition of these variations is important in the assessment of MR images of the knee.     

Conventional radiology and computed tomography in facial fractures

The possibilities and limitations of conventional radiography and CT in detecting maxillo-facial fractures are shown both experimentally and in a clinical setting. In 36 patients examined by both methods after maxillo-facial trauma, CT and conventional radiography (including pluridirectional tomography) proved to be equal in detecting fractures of the orbital roof, the anterior wall of the frontal sinus, the nasal bone and the pterygoid process. CT is inferior to conventional radiography in fracture of the orbital floor, the frontal base of the skull, the hard plate and the zygomatic arch. CT is superior to conventional radiography in fractures of the medial and lateral wall of the orbit, the posterior wall of the frontal sinus, the posterior, medial and anterior wall of the maxillary sinus as well as the zygomatic bone.     

经腹直肌外侧切口入路重建钢板辅助后柱顺行拉力螺钉治疗复杂髋臼骨折

目的评价经腹直肌外侧切口入路以前柱重建钢板配合后柱顺行拉力螺钉内固定治疗复杂髋臼骨折的临床疗效。方法回顾性分析自2012年5月~2014年1月本科收治的复杂型髋臼骨折9例,其中男性6例,女性3例;年龄27~74岁,平均39岁。骨折类型:横行骨折2例,前柱加后半横4例,双柱骨折3例,伴中心脱位1例。致伤原因:道路交通伤5例,坠落伤2例,压砸伤2例。所有患者均采用单一经腹直肌外侧切口入路,以前柱钢板结合后柱顺行拉力螺钉复位固定骨折,统计患者的平均手术时间和出血量,对术后骨折复位依据X线表现按Matta标准评估,临床疗效按照改良后的Merled'Aubigne和Postel髋关节评分标准。结果平均手术时间为200min(150~255min);平均失血量为730ml(300~1250ml);术后随访9~30个月,平均15.9个月。Matta评分结果达解剖复位者6例,满意2例,可1例;髋关节评分结果,优5例,良2例,可2例。所有患者3个月内均获骨性愈合,无感染、异位骨化及股骨头坏死等并发症的发生。结论采用单一经腹直肌外侧切口入路可为部分复杂髋臼骨折提供充足手术空间,尤其对方形区的显露和后柱拉力螺钉置入存在一定优势。     

急性颈椎外伤的MRI诊断

目的 分析急性颈椎外伤的MRI征象,评价MRI在急性颈椎外伤诊断中的价值及限度。方法收集急性颈椎外伤150例,均有MRI检查和X线平片,15例有CT片,采用14个参数进行分析记录。结果150例中MRI检出骨折51个,小关节脱位30个,椎体脱位35个;外伤性椎间盘突出40个,硬膜外血肿2例;脊髓损伤69例;脊髓受压迫20例;前、后纵韧带损伤21例;棘间韧带和黄韧带损伤15例;椎前血肿或水肿30例;椎旁和背侧软组织损伤40例;X线平片发现椎体骨折55个,椎体脱位35个;小关节脱位35例,附件骨折25个,椎前软组织肿胀20例。15例CT均发现骨折,小关节脱位,椎管狭窄。结论MRI在显示脊髓、韧带、椎间盘和软组织损伤方面优于CT和X线平片。MRI能全面反映颈椎各种损伤的病理特征,为评估颈椎稳定性提供充分的依据;MRI和X线片的骨折检出率没有明显差异,CT应该用于复杂的颈椎骨折检查。     

Computed tomography of calcaneal fractures: anatomy, pathology, dosimetry, and clinical relevance

Eighteen CT examinations were performed in 10 patients for the evaluation of acute intraarticular fractures and their follow-up. Fractures comparable to those in the patients were created in cadavers. The normal anatomy and the traumatically altered anatomy of the calcaneus in the axial, coronal, and sagittal planes are demonstrated by CT and corresponding anatomic sections. Scanning was performed in the axial plane, with subsequent reconstruction in the coronal and sagittal planes. The axial scans show disruption of the inferior part of the posterior facet, calcaneocuboid joint involvement, and widening of the calcaneus. The coronal scans show disruption of the superior part of the posterior facet, sustentaculum tali depression (involvement of middle and anterior facets), peroneal and flexor hallucis longus tendon impingement, and widening and height loss of the calcaneus. The sagittal scans show disruption of the posterior facet, calcaneocuboid joint involvement, and height loss of the calcaneus and allow the evaluation of Boehler's and Gissane's angles. All three planes show the position of major fracture fragments. Radiation dose to the foot was measured to be 0.1 rad (0.001 Gy) for plain film radiography (five exposures), 18 rad (0.18 Gy) for conventional tomography (20 cuts), and 2.6 rad (0.026 Gy) for axial CT examination.     

Ultrasound of the knee with emphasis on the detailed anatomy of anterior,medial, and lateral structures

Objective

To describe the detailed ultrasound anatomy of the anterior, medial, and lateral aspects of the knee and present the ultrasound examination technique used.

Materials and Methods

We present ultrasound using images of patients, volunteer subjects, and cadaveric specimens. We correlate ultrasound images with images of anatomical sections and dissections.

Results

The distal quadriceps tendon is made up of different laminas that can be seen with ultrasound. One to five laminas may be observed. The medial retinaculum is made up of three anatomical layers: the fascia, an intermediate layer, and the capsular layer. At the level of the medial patellofemoral ligament (MPFL) one to three layers may be observed with ultrasound. The medial supporting structures are made up of the medial collateral ligament and posterior oblique ligament. At the level of the medial collateral ligament (MCL), the superficial band, as well as the deeper meniscofemoral and meniscotibial bands can be discerned with ultrasound. The posterior part, corresponding to the posterior oblique ligament (POL), also can be visualized. Along the posteromedial aspect of the knee the semimembranosus tendon has several insertions including an anterior arm, direct arm, and oblique popliteal arm. These arms can be differentiated with ultrasound. Along the lateral aspect of the knee the iliotibial band and adjacent joint recesses can be assessed. The fibular collateral ligament is encircled by the anterior arms of the distal biceps tendon. Along the posterolateral corner, the fabellofibular, popliteofibular, and arcuate ligaments can be visualized.

Conclusion

The anatomy of the anterior, medial, and lateral supporting structures of the knee is more complex than is usually thought. Ultrasound, with its exquisite resolution, allows an accurate assessment of anatomical detail. Knowledge of detailed anatomy and a systematic technique are prerequisites for a successful ultrasound examination of the knee.     

伴前、中柱压缩的隐匿性胸腰椎屈曲牵张型骨折

目的 分析伴前、中柱压缩的胸腰椎屈曲牵张型骨折表现隐匿的原因,并探讨其发生机制、影像学诊断及手术复位方法.方法 回顾性分析我院2003年5月-2006年12月收治的屈曲牵张型胸腰椎骨折患者39例,其中伴前、中柱压缩的患者17例,评价影像学检查(X线片、CT和MRI)的诊断价值,所有患者均给予后路手术,术中利用先单纯撑开复位前、中柱再行后方轴向加压复位后柱两步骤复位法进行复位内固定治疗,并评价该方法的临床效果及安全性.结果 伴前、中柱压缩的患者占全部屈曲牵张骨折患者的43.6%,17例术前有6例误诊为单纯压缩性骨折,各种影像学检查不同程度发现后柱骨性和(或)韧带复合体损伤的阳性结果:X线片8例,CT平扫7例,螺旋CT多平面重建(MPR)11例,MRI17例.17例单纯后路撑开后有8例出现后柱过撑现象,给予后方再加压进行复位后效果较好.结论 伴前、中柱压缩的屈曲牵张型骨折的后柱损伤表现常较隐匿,有一定临床发生率,但容易误诊为单纯压缩性骨折,CT MPR和MRI对诊断有较大帮助.采用先撑开再加压的两步骤复位法效果满意,且比较安全.     

The fat pad sign following elbow trauma in adults: its usefulness and reliability in suspecting occult fracture

OBJECTIVE: An elbow joint effusion with no fracture seen on radiographs after acute trauma has become synonymous with occult fracture. This study evaluates the incidence of fracture in such cases as determined by MR imaging and the predictive value of an elbow joint effusion. METHODS: Twenty consecutive patients whose posttrauma elbow radiographs showed an effusion but no fracture and who were suitable for MR imaging were recruited. The elbow effusion size, represented by anterior and posterior fat pad displacement, was measured from the initial lateral elbow radiograph. Suitable candidates underwent MR imaging using a bone marrow sensitive sequence. The time between injury and MR imaging ranged from 0 to 12 days (mean 4 days). RESULTS: Seventy-five percent of the 20 patients who underwent MR imaging had radiographically occult fractures identified. Some (86.6%) of these fractures were located in the radial head, 6.7% were in the lateral epicondyle, and 6.7% were in the olecranon. Ninety percent had evidence of bone marrow edema. Fifteen percent had collateral ligament disruption identified on MR imaging, and 5% had a loose body. There was no change in patient management as a result of the additional imaging. The anterior fat pad displacement ranged from 5 to 15 mm (mean 9.25), and the posterior fat pad was elevated from 1 to 6 mm (mean 3.2). CONCLUSION: Our data using MR imaging suggests that fat pad elevation in the presence of recent trauma is frequently associated with a fracture. The size of the effusion, anterior/posterior fat pad elevation, or a combination of both does not correspond to the likelihood of an underlying fracture. MR imaging reveals a broad spectrum of bone and soft tissue injury beyond that recognizable on plain radiographs as demonstrated by all patients in this study.