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.     

Incidence and location of bone bruises after acute posterior cruciate ligament injury

BACKGROUND: In patients suffering from an anterior cruciate ligament injury, the incidence and location of bone bruises are well documented. This study reports data regarding bone bruises after acute posterior cruciate ligament injury. HYPOTHESIS: Bone bruises associated with posterior cruciate ligament injury are common, and their location differs from those seen with anterior cruciate ligament injury. STUDY DESIGN: Retrospective cohort study. METHODS: Thirty-five consecutive patients were identified as having a grade II or III posterior cruciate ligament tear, with an intact anterior cruciate ligament, in which a magnetic resonance imaging scan had been obtained within 20 days of injury. Magnetic resonance imaging scans were reviewed to document bone bruises, associated medial or lateral ligamentous injury, and meniscal and chondral abnormalities. RESULTS: Of the 35 patients, 29 (83%) had a bone bruise in at least one location. Bone bruises were found throughout the joint, more widely dispersed than is commonly seen with anterior cruciate ligament injury. Also, 29 patients had magnetic resonance imaging findings of associated ligamentous injury. Lateral bone bruises were associated with medial collateral ligament injury, whereas medial bone bruises correlated with posterolateral injury. CONCLUSIONS: The incidence of bone bruises associated with posterior cruciate ligament injury is similar to that seen with anterior cruciate ligament injury. Their location is more widely dispersed. The location of a bone bruise should lead to careful magnetic resonance imaging inspection and physical examination for ligamentous injury to the opposite side of the joint. Truly isolated posterior cruciate ligament injuries are rare, as most occur with osseous and some degree of associated ligamentous injury.     

MRI对急性膝关节骨挫伤的临床应用价值

目的：探讨MRI对急性膝关节骨挫伤的临床应用价值。方法：对117例X线平片显示阴性并行MRI检查的外伤性膝关节病例进行回顾性分析,MRI检查时间为外伤后2h．5天,重点观察股骨下端、胫腓骨上端及髌骨的骨质信号,前后交叉韧带、内外侧副韧带、内外侧半月板的完整性和信号情况。结果：急性外伤后骨挫伤的发生率为87．2％（102／117）,合并韧带损伤62例,半月板损伤49例,关节软骨损伤17例,隐性骨折21例。结论：急性膝关节外伤后骨挫伤的发生率较高,MRI能准确显示骨挫伤的部位、范围以及临近结构的损伤,对临床诊断、治疗具有重要意义。     

Acute paediatric ankle trauma: MRI versus plain radiography

OBJECTIVE: To evaluate the diagnosis of acute physeal ankle fractures on plain radiographs using MRI as the gold standard. METHODS: Sixty consecutive children, 29 with a clinical diagnosis of lateral ligament injury and 31 with physeal ankle fractures, were examined using both radiographs and MRI in the acute period. The imaging data were reviewed by three "masked" radiologists. The fracture diagnosis and Slater-Harris classification of radiographs were compared with findings on MRI. RESULTS: Plain radiography produced five of 28 (18%) false negative and 12 of 92 (13%) false positive fracture diagnoses compared with MRI. Six of the 12 false positive fractures were due to a misclassification of lateral ligament disruption as SH1 fractures, Altogether a difference was found in 21% of cases in either the diagnosis or the classification of the fractures according to Salter-Harris. All bone bruises in the distal tibia and fibula and 64% of bone bruises in the talus were seen in association with lateral ligament injuries. Talar bone bruises in association with fractures occurred on the same side as the malleolar fracture; talar bone bruises in association with lateral ligament disruption were seen in different locations. The errors identified on radiographs by MRI did not affect the management of the injury. CONCLUSIONS: The incidence of false negative ankle fractures in plain radiographs was small and no complex ankle fractures were missed on radiographs. The total extent of complex fractures was, however, not always obvious on radiographs. In an unselected series of relatively mild ankle injuries, we were unable to show a single case where the treatment or prognosis based on plain radiography should have been significantly altered after having done a routine MRI examination. Plain radiography is still the diagnostic cornerstone of paediatric ankle injuries.     

骨挫伤的MRI表现及意义

目的:探讨骨挫伤的MRI表现及意义。方法:回顾性分析两年内1 050名患者中的86例骨挫伤病例的MRI表现。结果:骨挫伤常伴有其他结构损伤,以股骨及胫骨外侧髁骨挫伤最多见,其次为股骨及胫骨内侧髁骨挫伤;常伴有前后交叉韧带、内外侧副韧带、内外侧半月板损伤及创伤性滑膜炎。结论:MRI对骨挫伤及其他结构损伤的发现有重要的临床意义。     

Arcuate sign of posterolateral knee injuries: anatomic,radiographic, and MR imaging data related to patterns of injury

Objective The arcuate sign is considered a pathognomonic sign for injuries of the posterolateral (PL) corner of the knee. The purpose of our study was to identify different patterns of injury to the fibular head that may associate with injuries to specific ligaments and tendons of the PL corner of the knee. The anatomic relations between the insertions of fibular collateral ligament (FCL), biceps femoris tendon (BFT), popliteofibular ligament (PFL), and arcuate ligament in normal cadaveric knees were also investigated.Design and patients Magnetic resonance imaging was performed in two cadaveric knees which subsequently were dissected. Radiopaque markers were placed upon the fibular insertions of the FCL, BFT, PFL, and arcuate ligament in the dissected knees, and knee radiographs were then obtained. Twelve patients with radiographic or MR imaging evidence of isolated injury to the PL corner of the knee were retrospectively reviewed, with regard to avulsion fractures and marrow edema in the fibular head and the integrity of the ligaments of the PL corner of the knee.Results and conclusions The PFL and arcuate ligament were seen to attach directly to the posterior and medial aspect of the styloid process of the fibular head. The FCL and BFT attached as a conjoined structure on the lateral aspect of the fibular head lateral, anterior and inferior to the attachment site of the PFL and arcuate ligament. Injury to the arcuate ligament or PFL was diagnosed in 8 patients who presented with a small avulsion fracture of the styloid process of the fibula (n=2), bone marrow edema in the medial aspect of the fibular head (n=3), or both (n=3). In 4 patients with injury to the conjoined tendon or FCL, a larger avulsion fragment and more diffuse proximal fibular edema were seen. Radiographic and MR imaging findings in injuries of the posterolateral corner of the knee may suggest injury to specific structures inserting in the fibular head.Presented at the 87th Annual Meeting of the Radiologic Society of North America, 2001.     

Posteromedial tibial plateau injury including avulsion fracture of the semimembranous tendon insertion site: ancillary sign of anterior cruciate ligament tear at MR imaging.

PURPOSE: To evaluate posteromedial tibial plateau injuries of or about the semimembranous tendon insertion site and their association with anterior cruciate ligament (ACL) tears on magnetic resonance (MR) images. MATERIALS AND METHODS: A retrospective study of MR images and conventional radiographs was performed in 10 patients with posteromedial tibial plateau injuries, including avulsion fractures of the semimembranous tendon insertion site. Associated abnormalities were analyzed, including ACL tears, medial meniscal tears, and other lateral femorotibial compartment injuries. Findings from the clinical history and physical examination were correlated with radiographic and MR imaging findings. Nine patients had arthroscopically or surgically documented ACL tears. RESULTS: All 10 patients had ACL tears at MR imaging. Five patients had posteromedial tibial plateau fractures: Four had avulsion fractures of the tendon insertion site, and one had a fracture lateral to the site. Five patients had posteromedial tibial plateau bruises: Two had bruises at the tendon insertion site. Five patients had tears of the posterior horn of the medial meniscus. Two patients had posterior meniscocapsular separations. Three patients showed evidence of the O'Donoghue triad. Six patients had bruises of the lateral tibial plateau and of the lateral femoral condyle. CONCLUSION: There appears to be an association between posteromedial tibial plateau injuries and ACL tears. Posteromedial tibial plateau injuries may be predictive of ACL status.     

Anterior rim tibial plateau fractures and posterolateral corner knee injury

The aim of this study was to review MRI findings of clinically suspected posterolateral corner knee injuries and their associated internal derangements. Sixteen knees in 15 patients who had evidence of a posterolateral corner knee injury on the physical exam underwent MRI to evaluate the posterolateral corner of the knee and to look for associated injuries. Two musculoskeletal radiologists reviewed the scans. Surgery was performed on 10 of the knees. Tibial plateau fractures were present in 6 knees; 5 of the fractures were anteromedial rim tibial plateau fractures. The popliteus muscle was injured in 13 knees and the biceps femoris in 6 knees. The lateral collateral ligament was ruptured in 12 knees. The posterior cruciate ligament was completely ruptured in 7 knees and avulsed from its tibial attachment in 1 knee. Eleven knees had a complete anterior cruciate ligament rupture. The anterior cruciate ligament was edematous without complete disruption of all fibers in 3 knees. There was excellent correlation between the MRI results and operative results in regard to the presence of a posterolateral corner injury of the knee (9 of the 10 knees had a posterolateral corner injury). In our study MRI readily detected posterolateral corner injuries. Posterolateral corner injuries of the knee are frequently associated with a variety of significant injuries, including cruciate ligament tears, meniscus tears, and fractures. Fractures of the peripheral anteromedial tibial plateau are not common; however, given their relatively common occurrence in this study, they may be an indicator of a posterolateral corner injury to the knee.     

Internal derangement of the knee after ipsilateral femoral shaft fracture: MR imaging findings

Objective. This study uses magnetic resonance (MR) imaging to delineate the types and frequencies of injuries seen in the knee after ipsilateral femoral shaft fracture. We also compare the results of the orthopedic knee examination with the MR findings. Design and patients. MR imaging of the ipsilateral knee was performed on 34 patients with closed femoral shaft fractures. Indications for knee MR imaging included knee pain at the time of fracture, soft tissue swelling or an effusion of the knee, or a positive knee examination under anesthesia. The patients had a mean age of 27 years and all were stabilized with intramedullary nails. Imaging was performed a mean time of 2.5 days after surgery. All patients had knee examinations done under anesthesia, and the MR results were compiled and compared with the clinical examinations. Results. Ninety-seven percent of patients demonstrated knee effusions. Twenty-seven percent of patients demonstrated meniscal tears, with the posterior horn of the medial meniscus most frequently torn. The medial collateral ligament was the most frequent site of ligamentous injury (38%) followed by the posterior cruciate ligament (21%). Fifty percent of patients had injuries of the extensor mechanism. Bone bruises were noted in 32% of patients. Articular cartilage injuries were confined to the patella in four cases. One occult tibial plateau fracture and one meniscocapsular separation were seen. Conclusions. There is a common incidence of both ligamentous and meniscal injury to the knee after ipsilateral femoral shaft fracture. MR imaging can be useful in assessing the extent of injury, and may reveal findings unsuspected after clinical examination of the knee.     

外伤性膝关节前外侧韧带损伤的MR影像特征及相关性分析

目的探讨外伤所致膝关节前外侧韧带损伤病人的MR影像特征,并分析其与前交叉韧带撕裂、外侧半月板撕裂及骨挫伤的相关性,为深入研究前外侧韧带对膝关节稳定性的作用提供可靠依据。方法回顾性分析2016年1月—2017年2月间因外伤进行膝关节MRI检查的320例病人(共321膝)的影像资料。采用美国GE公司生产的Signa HDe 1.5 T MR扫描设备,分别行膝关节斜矢状面T1WI、质子密度加权成像(PDWI)和冠状面、横断面PDWI扫描。根据前外侧韧带的完整性和损伤部位对所有病人进行分类统计。采用独立性卡方检验对前外侧韧带撕裂与前交叉韧带撕裂、外侧半月板撕裂及骨挫伤的相关性进行分析。结果全部病人膝关节MR影像均可显示前外侧韧带,显示率为100%。151/321膝(47.0%;95%CI为41.6%~52.5%)存在前外侧韧带损伤,其中累及胫骨部、股骨部及半月板部的分别为97膝、96膝及65膝。前交叉韧带撕裂158膝,外侧半月板撕裂98膝,股骨外侧髁挫伤58膝,外侧胫骨平台挫伤71膝,分别与前外侧韧带撕裂具有相关性(均P0.001)。结论 MRI检查可以很好地显示前外侧韧带解剖及其损伤情况。膝关节前外侧韧带损伤与前交叉韧带撕裂、外侧半月板撕裂及膝外侧骨挫伤具有相关性。     

外侧半月板桶柄状撕裂低场MRI特殊征象分析

目的分析膝关节外侧半月板桶柄状撕裂(bucket-handletears,BHT)的低场MRI特殊征象。资料与方法回顾性分析12例经关节镜证实为膝关节外侧半月板BHT患者的低场强MRI图像,总结MRI征象,除碎块内移征、外周残半月板征、半月板翻转征、空领结征外,着重分析双前交叉韧带征、厚饼征、三韧带征。结果 12例外侧半月板BHT中,碎块内移征10例、外周残半月板征9例、半月板翻转征6例、空领结征12例、双前交叉韧带征3例、厚饼征4例、三韧带征3例。结论碎块内移征、外周残半月板征、半月板翻转征、空领结征见于内侧半月板BHT,同样见于外侧半月板BHT,前交叉韧带征、厚饼征和三韧带征为外侧半月板BHT特殊征象。     

半月板桶柄样撕裂的MRI表现

目的 探讨半月板桶柄样撕裂的MRI征象. 资料与方法 对经关节镜证实的半月板桶柄样撕裂56例(58侧)患者的MRI表现进行研究. 结果 领结残破征21膝,空领结征28膝,双前交叉韧带征6膝,双后交叉韧带征19膝,双半月板前角征11膝,前角异常肥大征5膝,双半月板后角征16膝,后角异常肥大7膝,后角残破征19膝,厚饼征6膝,半月板分离移位征53膝.合并膝关节囊积液58膝、股骨(或胫骨)挫伤36膝、内侧副韧带损伤6膝、前交叉韧带损伤5膝、后交叉韧带损伤9膝、关节软骨损伤13膝、骨梗死2膝. 结论 空(残)领结征、后角残破征、双后交叉韧带征及半月板分离移位征提示半月板桶柄样撕裂.     

MRI detection of unsuspected vertebral injury in acute spinal trauma: incidence and significance

Objective. Multilevel spinal injury is well recognised. Previous studies reviewing the radiographs of spinal injury patients have shown an incidence of 15.2% of unsuspected spinal injury. It is recognised that magnetic resonance imaging (MRI) can identify injuries that are not demonstrated on radiographs. The objective of this study was to determine the incidence and significance of spinal injuries using MRI in comparison with radiographs. Design and patients. The radiographs and MR images of 110 acute spinal injury patients were reviewed independently of each other and the findings were then correlated to determine any unsuspected injury. Results. MRI detected vertebral body bone bruises (microtrabecular bone injury) in 41.8% of spinal injury patients which were not seen on radiographs. These bone bruises were best appreciated on sagittal short tau inversion recovery MR sequences and seen at contiguous and non-contiguous levels in relation to the primary injury. Conclusion. This level of incidence of bone bruises has not previously been appreciated. We recommend that patients undergoing MRI for an injured segment of the spine are better assessed by MRI of the entire spine at the same time to exclude further injury. Received: 17 April 2000 Revision requested: 19 June 2000 Revision received: 6 September 2000 Accepted: 27 November 2000     

The effects of time course after anterior cruciate ligament injury in correlation with meniscal and cartilage loss

In this study, 130 consecutive patients with anterior cruciate ligament insufficiency who were undergoing ligament reconstruction underwent arthroscopic examination at the time of reconstruction, and any loss of meniscal or chondral integrity was documented in a systematic fashion. In these patients, a greater proportion of the medial meniscus was lost compared with the lateral meniscus (16% versus 5%). On average, 6 cm2 of the articular cartilage was damaged (5.2 cm2) or lost (0.8 cm2), with the area of damage and loss greatest on the medial femoral condyle. Patients whose injuries had occurred more than 2 years before the examination had more than sixfold greater cartilage loss and damage compared with those whose injuries had occurred within the past 2 months. Meniscal loss was associated with a threefold increase in cartilage damage or loss. The group of patients with meniscal loss whose initial anterior cruciate ligament injury occurred more than 2 years before examination exhibited 18 times the amount of cartilage loss or damage as did the group that had no meniscal loss and whose injury occurred less than 1 month before examination.     

MR IMAGING OF DISPLACED MENISCAL TEARS OF THE KNEE: Importance of a "disproportional posterior horn sign"

Purpose: Meniscal tears associated with displaced fragments are clinically significant. We propose the "disproportional posterior horn sign" as a supportive criterion to identify a posterocentrally displaced meniscal fragment on MR imaging studies. If the meniscal posterior horn in the central portion appears larger than that in the peripheral section, it is considered positive for "disproportional posterior horn sign".Material and Methods: MR images obtained in 42 patients with 43 lesions, confirmed to have displaced meniscal tears, were included in this study. The MR images were retrospectively evaluated for the presence of the "disproportional posterior horn sign", as well as the other known signs.Results: The "disproportional posterior horn sign" was seen in 9 (20.9%) of 43 lesions, including 1 lateral discoid meniscal tear, 5 lateral meniscal tears and 3 medial meniscal tears. Five of them also had other signs of a displaced meniscal fragment. However, the remaining 4 cases only exhibited the "disproportional posterior horn sign". For the other MR signs, the "absent bow tie sign" was detected in 40 (93%) of 43 lesions, the "flipped meniscus sign" in 27 (62.8%) of 43 lesions, the "double posterior cruciate ligament sign" in 17 (39.5%) of 43 lesions and the "notch fragment sign" in 22 (51.2%) of 43 lesions.Conclusion: The "disproportional posterior horn sign" is helpful in demonstrating a posterocentrally displaced meniscal fragment, especially when other characteristic signs are unremarkable or absent.     

急性前交叉韧带断裂合并膝关节骨挫伤的临床研究

目的 :总结前交叉韧带急性断裂时骨挫伤的不同类型和分布 ,探讨骨挫伤与关节软骨损伤的关系。方法 :回顾性研究 37例前交叉韧带急性断裂合并膝关节骨挫伤患者的影像学和临床资料 ,分析前交叉韧带急性断裂时骨挫伤的MRI不同表现类型、分布以及关节镜下软骨损伤的情况。结果 :MRI显示本组病例骨挫伤共 5 7处 ,其中Ⅰ型 1 4处 (2 4 .6 %) ,Ⅱ型 32处 (5 6 .1 %) ,Ⅲ型 3处(5 .3%) ,Ⅳ型 6处 (1 0 .5 %) ,Ⅴ型 2处 (3.5 %)。共 5 4处 (94 .7%)骨挫伤位于外侧间室 ,其中股骨外髁骨挫伤 31处 ,胫骨外侧平台骨挫伤 2 3处。经关节镜下手术发现 9处 (1 5 .8%)骨挫伤部位有软骨损伤表现。结论 :急性前交叉韧带断裂时 ,骨挫伤通常发生在外侧间室 ,尤其集中在外侧股骨髁前部以及外侧胫骨平台后部。关节镜下软骨损伤与骨挫伤并非一一对应的关系。     

MR imaging of anterior cruciate ligament tears: is there a gender gap?

Objective Clinically, females receive anterior cruciate ligament (ACL) tears more commonly than males. We explored whether gender differences exist in MR imaging patterns of ACL tears.Design and patients At 1.5T, two observers evaluated MR examinations of 84 consecutive age-matched patients (42 males, 42 females, aged 16–39) with ACL tears, for mechanism of injury, extent and type of tear, the presence of secondary signs and associated osseous, meniscal and ligamentous injuries.Results The most common mechanism of injury for both females and males was the pivot shift mechanism (67 and 60%, respectively). Females were more commonly imaged in the acute stage of tear than males (98 and 67%, respectively, p=0.001) and more commonly possessed the typical posterolateral tibial bone contusion pattern (88 and 62%, respectively, p=0.0131). Males exhibited a deeper femoral notch sign (2.7 and 2.0 mm, p=0.007) and medial meniscal, lateral collateral ligament and posterior cruciate ligament injuries more commonly than females (48 and 24%, p=0.009, 30 and 7%, p=0.035, 17 and 0%, p=0.035). There was no significant difference between genders for the presence of other secondary signs and contusion patterns, associated lateral meniscal tears, presence of O'Donoghue's triad or associated medial collateral ligament injuries.Conclusion Gender differences in MR imaging patterns of ACL tears exist: females are more commonly imaged in the acute stage and more commonly possess posterolateral tibial bone contusions; males have a more severe presentation than females, associated with more severe lateral femoral condyle and soft tissue injuries.     

前交叉韧带斜冠状面薄层解剖断面与MRI表现对照研究

目的对冰冻膝关节前交叉韧带（ACL）斜冠状面薄层解剖断面与正常人膝关节MRI特点进行对照研究，为ACL损伤分级诊断建立基础。方法1例（1只）膝关节标本行斜冠状面MRI确定角度，冰冻后沿斜冠状面1mm层厚铣切，观察ACL薄层解剖特点。选择50名正常人对其ACL进行MR斜冠状面扫描，观察ACL的MRI特点。结果1只膝关节标本的ACL在斜冠状面薄层断面清晰显示其全程走行，清晰地显示ACL前内束与后外束，前内束从股骨髁附着点后上方区自后向外侧及前内侧走行，止于髁间棘附着区前内侧方，后外侧束从股骨髁附着点前下方区，自后外侧及外下走行，止于髁间棘附着区后外侧方。斜冠状面MRI能够显示50名正常人ACL全程，显示率为100％。MRI能够区分ACL前内束与后外束结构，显示前内束自后外侧向前内走行，止于髁间棘附着区前内侧方，后外束自后外侧向外下走行，止于髁间棘附着区后外侧方。MRI显示ACL走行与薄层断面显示的走行一致。结论斜冠状面是观察ACL的最佳方位，临床对怀疑ACL损伤的患者必要时行MR斜冠状面扫描。     

膝关节半月板及其损伤的MRI研究

目的　研究正常和损伤的膝关节半月板的MRI表现。方法　对经手术、关节镜或临床证实的 2 6例共 3 2个损伤的半月板与 15例正常的膝关节半月板进行回顾性MRI对比观察。结果　显示正常膝关节半月板在T1WI和T2 WI上均呈三角形低信号。 3 2个损伤的半月板 ,其中内侧损伤 15个 ,外侧损伤 11个 ,两侧半月板同时损伤 3例 6个 ,将 3 2个损伤的半月板按Stoller的 4级分法分类 ,其中 0级 0个 ,I级 6个 ,Ⅱ级 12个 ,Ⅲ级 14个。 18例出现并发症 ,其中合并半月板囊肿 6例 ,内侧副韧带损伤 10例 ,外侧副韧带损伤 9例 ,前交叉韧带损伤 7例 ,后交叉韧带损伤 6例 ,骨挫伤 8例 ,骨折 5例 ,关节囊积液 11例 ,膝关节周围软组织内瘀血 6例。结论　MRI能够清晰显示膝关节半月板的解剖结构 ,能准确诊断半月板的损伤并进行分级 ,还能发现多种并发症。