股骨头坏死影像学表现

WordsSubchondralInsufficiencyFracture：软骨下不全骨折OsteonecrosisoftheFemoralHead：股骨头坏死Convex凸ncavity凹第1页，共30页。软骨下不全骨折（Subchondralinsufficiencyfracture,简称SIFs）

1、软骨下机能不全性骨折是非外伤性的一种骨折。2、最常见的病因：骨质疏松，不常见的病因是骨质软化症或骨不全症、甲状旁腺功能亢进和类风湿性关节炎等。3、发病原理：正常软骨可忍受正常的生物机械应力，当由于上述病因变得软弱时，可出现软骨下骨折，并发展为软骨下萎陷，为此需认识此病作出早期诊断，多数患者经保守治疗后可自愈。

第2页，共30页。OBJECTIVEThepurposeofthisarticleistoverifythehypothesisthatosteonecrosisandsubchondralinsufficiencyfractureofthefemoralheadcanbedifferentiatedonthebasisoftheirappearanceonMRI.第3页，共30页。SUBJECTSANDMETHODS1BetweenMay1998andFebruary2009,wereviewed30consecutivehipsin30patients,60yearsoldorolderatthetimeofonsetofhippain,withradiologicevidenceofsubchondralcollapseofthefemoralheadandwithbothMRimagesandhistologicresultsavailable.第4页，共30页。SUBJECTSANDMETHODS2Thepatientsweredividedintotwogroupaccordingtotheshapeoflow-intensitybandsonT1-weightedimages.Thefirstgroupshowedconcavityofthearticularsurface,whichischaracteristicofosteonecrosis,andthesecondgroupshowedanirregularconvexityofthearticularsurface,whichischaracteristicofsubchondralinsufficiencyfracture.第5页，共30页。AInosteonecrosis,low-intensitybandissmooth,concavetoarticularsurface,andcircumscribesallofnecroticsegments.BInsubchondralinsufficiencyfracture,low-intensitybandisirregular,convextoarticularsurface,anddiscontinuous.第6页，共30页。RESULTSSixteenhips(53.3%)showedevidenceofosteonecrosis,and14(46.7%)showedevidenceofsubchondralinsufficiencyfracture,whichwasconsistentwiththecorrespondinghistopathologicdiagnoses.Inallcasesofosteonecrosis,thepatienthadahistoryofeithercorticosteroidintakeoralcoholabuse.Amongpatientswithsubchondralinsufficiencyfracture,theproportionofwomenwassignificantlyhigherthanthatamongpatientswithosteonecrosis.Acrescentsign(subchondralfracture)waspresentradiographicallyinabouthalfofallcasesinbothgroups.第7页，共30页。TABLE1:ClinicalCharacteristicsofPatientsWithOsteonecrosisor

SubchondralInsufficiencyFracture第8页，共30页。CONCLUSIONTheresultsofthepresentstudysuggestthattheshapeofthelow-intensitybandonMRIisusefulforthedifferentiatingsubchondralinsufficiencyfracturefromosteonecrosis.Inaddition,amongosteoporoticelderlywomenwithoutanyhistoryofcorticosteroidintakeoralcoholabuse,adiagnosisofsubchondralinsufficiencyfractureshouldbeconsidered.第9页，共30页。64-year-oldmanwithhistoryofalcoholabuseandosteonecrosis.A,Anteroposteriorradiographoflefthip(Singhindexofseverityofosteoporosis,gradeV)obtainedattimeofonsetofpainshowsbothcrescentsignandcollapseoffemoralheadatsuperolateralportion(arrows).第10页，共30页。B,CoronalT1-weightedimage(TR/TE,470/15)showsdiffuselowsignalintensityinfemoralneckatlateralportionandintertrochantericarea.Low-intensitybandonT1-weightedimageisconcavetoarticularsurface(arrows).第11页，共30页。“线样征”位于股骨头颈前上部病灶周围多呈空间锥形分布,锥尖指向股骨头基底部或股骨颈。Glimcher认为修复开始后,肉芽组织自股骨颈或股骨头基底部向死骨区爬行。肉芽组织到达并吸收骨皮质时,皮质承载力减弱。在重力作用下自此皮质薄弱区于松质骨内产生多条微骨折线,因应力作用微骨折线多位于股骨头前上部周围。肉芽组织在微骨折处大量增生堆积、吸收坏死骨小梁并于外围大量成骨,从而形成T2WI上的“双线症”。第12页，共30页。D,AxialsliceofT1-weightedimage(500/15)showsthatlow-intensitybandcircumscribesallofnecroticsegments(arrows).第13页，共30页。E,Cutsectionofresectedfemoralheadshowszonalpattern(necrotic,reparative,andviablezones).Subchondralfractureline(arrow)correspondingtocrescentsignonradiograph(A)isseen.第14页，共30页。新月征形成机制因皮质断裂塌陷时,关节软骨在一段时间内尚保持完整,形成软骨下负压。股骨头体液内气体在负压作用下溢出并进入囊腔。第15页，共30页。第16页，共30页。F,Histopathologicappearanceofnecroticregion,whichshowsaccumulationofbonemarrowcelldebris,andbonetrabeculaewithemptylacunaebeneathfracturelineareseen.(HandE,×40)第17页，共30页。G,Thereisrepairtissueinreparativezone,includingvasculargranulationtissue,fibroustissue.(HandE,×20)第18页，共30页。Fig.3—75-year-oldwoman,withouthistoryofeithercorticosteroidintakeoralcoholabuse,withsubchondralinsufficiencyfracture.Anteroposteriorradiographoflefthip(Singhindexofseverityofosteoporosis,gradeV)obtainedattimeofonsetofpainshowsbothcrescentsignandcollapseoffemoralheadatsuperolateralportion(arrows).第19页，共30页。Thefrequencyofthecrescentsigninthesubchondralinsufficiencyfracturegroupwassimilartothatinosteonecrosisgroupinthecurrentstudy,thusindicatingthatthecrescentsignisnotsufficienttodifferentiateosteonecrosisfromsubchondralinsufficiencyfracture.第20页，共30页。B,CoronalT1-weightedimage(TR/TE,470/25)showsdiffuselowsignalintensityinfemoralheadandneck.Low-intensitybandisparallelto

subchondralboneendplate(arrows).Thelow-intensitybandonT1-weightedimagesinsubchondralinsufficiencyfracturecorrespondshistologicallytothefracturelineandassociatedfracturerepairtissue.Therefore,theshapeofthelow-intensitybandgenerallytendstobeirregular,disconnected,andconvextothearticularsurface.第21页，共30页。D,AxialslicesofT1-weightedimage(500/15)showlow-intensitybandmainlyinanteriorregion,whichisinterruptedinmiddle(arrows).第22页，共30页。E,Fat-saturatedcontrast-enhancedMRI(fromimageshowninD)(605/14)inwhichpartofproximalportionbeyondlow-intensitybandshowscontrastenhancementindicatingperfusion(arrows).第23页，共30页。F,Cutsectionofresectedfemoralheadshowssubchondralfractureline(blackarrow)andwhitishlinearshapedareabeneatharticularcartilage(whitearrow).第24页，共30页。G,Bandregionhistopathologicallycorrespondstofracturecallus,reactivecartilage,andgranulationtissue.(HandE,×40)第25页，共30页。第26页，共30页。Limititions样本量小对于软骨下不全骨折早期表现，如软骨下水肿，由于在平片上未见异常，未被纳入。仅4例进行了增强MR检查。第27页，共30页。真爱生命，拒绝酒精第28页，共30页。统计学方法StatisticalanalyseswereperformedusingFisher’sexact

probabilitytestwithregardtosex,ahis