Do computed tomography and its 3D reconstruction increase the reproducibility of classifications of fractures of the proximal extremity of the humerus?

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r e v b r a s o r t o p . 2014;49(2):174–177

w w w . r b o . o r g . b r

Original

Article

Do

computed

tomography

and

its

3D

reconstruction

increase

the

reproducibility

of

classifications

of

fractures

of

the

proximal

extremity

of

the

humerus?

夽

,

夽夽

Thaís

Matsushigue,

Valmir

Pagliaro

Franco,

Rafael

Pierami

∗

_,

Marcel

Jun

Sugawara

Tamaoki,

Nicola

Archetti

Netto,

Marcelo

Hide

Matsumoto

UniversidadeFederaldeSãoPaulo,SãoPaulo,SP,Brazil

a

r

t

i

c

l

e

i

n

f

o

Articlehistory:

Received4September2012 Accepted1August2013 Availableonline27March2014

Keywords:

Fracturesofthe humerus/radiography Fracturesofthe humerus/classification Tomography

a

b

s

t

r

a

c

t

Objective:todeterminewhether3Dreconstructionimagesfromcomputedtomography(CT)

increasetheinterandintraobserveragreementoftheNeerandArbeitsgemeinschaftfür Osteosynthesefragen(AO)classificationsystems.

Methods:radiographic images and tomographic images with 3D reconstruction were

obtainedinthreeshoulderpositionsandwereanalyzedontwooccasionsbyfour inde-pendentobservers.

Results:theradiographicevaluationdemonstratedthatusingCTimprovedtheinterand

intraobserveragreementoftheNeerclassification.ThiswasnotseenwiththeAO classifi-cation,inwhichCTwasonlyshowntoincreasetheinterobserveragreement.

Conclusion:useof3DCTallowsbetterevaluationoffractureswithregardtotheircomponent

partsandtheirdisplacements,butneverthelesstheintraobserveragreementpresentedis lessthanideal.

A

tomografia

computadorizada

e

sua

reconstruc¸ão

3D

aumentam

a

reprodutibilidade

das

classificac¸ões

das

fraturas

da

extremidade

proximal

do

úmero?

Palavras-chave:

Fraturasdoúmero/radiografia Fraturasdoúmero/classificac¸ão Tomografia

r

e

s

u

m

o

Objetivo:determinarseasimagensdareconstruc¸ão3Ddatomografiacomputadorizada(TC)

aumentamaconcordânciaintereintraobservadordossistemasdeclassificac¸ãodeNeere ArbeitsgemeinschaftfürOsteosynthesefragen(AO).

夽_Please_cite_this_article_as:_Matsushigue_T,_Franco_VP,_Pierami_R,_Tamaoki_MJS,_Netto_NA,_Matsumoto_MH._A_tomografia_{computadorizada}

esuareconstruc¸ão3Daumentamareprodutibilidadedasclassificac¸õesdasfraturasdaextremidadeproximaldoúmero?.RevBrasOrtop. 2014;49:174–177.

夽夽

WorkperformedintheDepartmentofOrthopedics,EscolaPaulistadeMedicina,UniversidadeFederaldeSãoPaulo.

∗ _{Corresponding}_author_.

E-mail:rpierami@gmail.com(R.Pierami).

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rev bras ortop.2014;49(2):174–177

175

Métodos: foram obtidas imagens radiográficasem três posic¸ões do ombro e imagens

tomográficascomreconstruc¸ão3D,queforamanalisadasemdoistemposporquatro obser-vadoresindependentes.

Resultados: aavaliac¸ãoradiográficademonstrouqueousodaTCmelhoraa

concordân-ciaintraeinterobservadoresparaaclassificac¸ãodeNeer.Omesmonãofoiobservadona classificac¸ãoAO,naqualaTCdemonstrouaumentosomentedaconcordância interobser-vadores.

Conclusão: ousodeTC3Dpermiteumamelhoravaliac¸ãodafraturaquantoàspartesquea

compõemeaosseusdesvios,masmesmoassimapresentaumaconcordância intraobser-vadoresmenordoqueaideal.

Introduction

Fracturesoftheproximalextremityofthehumerushavean incidenceofapproximately63–105per100,000peryear1–4_and accountfor5%ofallinjuriestotheappendicularskeleton.4,5 Their incidenceislowamongindividualsunder theage of 40 years and increases exponentially afterthis age. There isgreaterprevalenceofthesefracturesamongwomen,and female cases account for around 70–80%.1–5 _The charac-teristics of the fracture (line, location, joint involvement, comminution and degree of soft-tissue involvement) are directlyrelatedtotheforceofthetrauma,positionofthelimb atthetimeofthetraumaandbonequality.6,7

Severalclassificationsystemshavebeendevelopedinan attempttoguidetreatmentsandcompareresults.Fora classi-ficationsystemtobeconsideredgood,itneedstobevalidated, reliableandreproducible,aswell asguidingthetreatment, predictingpossiblecomplicationsandprovidingaprognosis. Furthermore,itshouldfunctionasamechanismfor compar-ingtheresultsobtainedfromthedifferenttypesoftreatment. TheclassificationmethodoftheArbeitsgemeinschaftfür Osteosynthesefragen/AssociationfortheStudyofInternal Fix-ation (AO/ASIF), which was created in1986 and revised in 1990,usesanalphanumericsystemfordividingfracturesof the proximalextremity ofthe humerusinto 27 subgroups. Threebasic typesofinjuryare taken into consideration in this classificationmethod:extra-articular single-focus frac-tures,extra-articularbifocalfracturesandjointfractures.The threegroupsareorganizedinincreasingorder of complex-ityandtreatmentdifficultyandaccordingtotheprognosis. Thisisoneofthemostcompleteclassificationsystems,but itsintra-andinterobserverreproducibilityhavebeenshown tobeproblematicwithregardtothedivisionsbetweengroups andsubgroups.8

Neerused the partsdefined byCodmanto proposethe classificationsystemthattodayismostfrequentlyused.9,10 The four parts of the proximal extremity of the humerus definedinthisclassificationmethodarethegreater tuberos-ity,lessertuberosity,diaphysisofthehumerusandhumeral head.For these partstobeconsidered tobefractured, the fragmentshouldhavea displacementgreater than 1cmor 45◦_,_except_for_the_greater_tuberosity,_which_is_considered_to

bea fracturedpart ifthere isa displacement greater than 0.5cmoranangleof45◦_. _Thus,_the_fractures _can_be

classi-fiedasaffectingone,two,threeorfourparts.Onecriticismof

Neer’sclassificationisthatitdoesnotconsiderthe possibil-ityofglenohumeraldislocationassociatedwiththefracture, whereasthisisencompassedintheAOclassification.

Recently,comestudieshavequestionedthe reproducibil-ityofclassificationsoffracturesoftheproximalextremityof thehumerus.11–16 _The_main_criticism_of_these_{classification} systemsrelatestothedifficultyofassessingthedegreeof dis-placementandangulationthroughusingsimpleradiographs alone. In this regard, computed tomography (CT) provides greaterdetailingoftheinjuryandhasbeenwidelyusedfor evaluatingthesefractures,especiallyinsituationsofgreater complexity.However,this examinationisnotharmless:the patientreceivesahighdoseofradiation.Moreover,its indica-tionsarestillnotwellestablishedanditsbenefitisnotclearly proven.12,13,16

Giventhat treatmentof thesefractures dependson the radiographic evaluationand thatthe classificationsystems mostused(AOandNeer)presentlowreproducibility,11–13_we developedthepresentstudywiththeaimofevaluatingthe reproducibilityofthetwoclassificationsystemsmostusedin oursetting,bymeansofradiographyandCTwith3D recon-struction.

Materials

and

methods

ThisstudywassubmittedforappraisalbytheResearchEthics CommitteeoftheFederalUniversityofSãoPaulo(UNIFESP) under the number 0212/11, onFebruary 24,2011, and was approved.

Aretrospectiveanalysiswasconductedonallthepatients withadiagnosisoffracturingoftheproximalextremityofthe humerusattendedintheShoulderandElbowSurgerySector ofHospitalSãoPaulo,UNIFESP,betweenAugust2009andApril 2012.

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rev bras ortop.2014;49(2):174–177

regionstudiedandthosepresentingfracturesthatwere con-sideredtobepathologicalwerealsoexcluded.

Theimageswereanalyzedbyfourindependentobservers: onethird-yearresidentinorthopedicsandtraumatology(C); onetraineeorthopedistintheshoulderandelbowsector(B); andtwoorthopedicsandtraumatologyspecialistsinthefield ofshoulder and elbowsurgery (Aand D). These observers independentlyclassifiedthefracturesinaccordancewiththe AO/ASIFandNeerclassificationmethods,bymeansof anal-ysis on images that had previously been digitized. These analysesweredonetwice,attwoseparatetimeswitha one-week interval between them. At the two evaluations, the imageswere randomizedinto different sequences soas to avoidbias.

Thedataweregatheredandsubjectedtostatistical anal-ysis. The kappa coefficient () was obtained in order to

determinethe inter- and intraobserver concordanceofthe classifications.Thekappavaluesvariedfrom−1to+1;values

between−1and0indicatedthattheconcordancewasless

thanexpectedandattributablepurelytochance;valuesof0 indicatedthattheconcordancewithsimilartochance;and valuesof+1indicatedtotalconcordance.Generally,valuesof 0.5areconsideredtobeunsatisfactory,valuesbetween0.5and 0.75aresatisfactoryandappropriateandvaluesgreaterthan 0.75areexcellent.17

Results

The method with greatest interobserver concordance was the Neer classification using CT (=0.57). CT provided

greater interobserver concordance in both classifications

(Table1).

Inrelationtointraobserverconcordance,noincreasewas observedthroughusingCT appliedtotheAOclassification (=0.39forradiographyand=0.33forCT).However,forthe

Neerclassification,therewasanincreaseinthisconcordance (=0.45forradiographyand=0.56forCT)(Table2).

Table1–Interobserverconcordanceusingradiography andCTexaminationswiththeNeerandAO

classificationsystems.

Examination Classification Kappa

Radiography Neer 0.37

AO 0.25

Tomography Neer 0.57

AO 0.36

Table2–MeanintraobserverconcordancefortheNeer andAOclassificationsystemswhenCTandX-ray examinationswereused.

Examination Classification Kappa

Radiography Neer 0.45

AO 0.39

Tomography Neer 0.56

AO 0.33

Discussion

Overrecentdecades,withtheintroductionofnew technolo-giesfordiagnosingfracturesoftheproximalextremityofthe humerus, it has been askedwhether using CT with three-dimensional reconstruction (3D CT) might providebenefits withregardtoidentifyingthefracturepatternandguidingthe typeoftreatmenttouse.11–16 _However,_CT_is_not_a_harmless method,becauseitexposesthepatienttoahighdoseof radi-ation.Moreover,thecostofthismethodisstillmuchhigher thanthatofsimpleradiography.Forthesereasons,new stud-iesshouldbeconductedtodefinetheusefulnessandpossible indicationsforusingCT.

In our study, the interobserver concordance using the Neer classification by means of radiographs was unsatis-factory (=0.37). This finding is in agreement with other

published studies thathad this aim.12,13,18 _When _the eval-uation was done using CT, the interobserver concordance became satisfactory (=0.57), asalso seenin other studies

alreadypublished,12,13_which_justifies_the_use_of_CT._In_relation totheAOclassification,thevaluesfoundusingradiography and CT were considered tobe unsatisfactory, eventhough therewasanincreaseinthekappavalue(=0.25for

radio-graphyand =0.36forCT).Theseunsatisfactoryvaluescan

perhapsbeexplainedbythecomplexityoftheclassification system.Thesameisobservedwhenthesystemisusedto clas-sifyfracturesinothersegments,suchasthedistalextremity oftheradius,theankleorthefemoralneck.19–22

In relationtointerobserver concordance,CT wasshown tobeusefulwhentheNeerclassificationwasused,and pro-ducedasatisfactoryvalue(=0.56).Thishasalsobeenshown

byotherstudies.11,12,18_For_the_AO_{classification,}_CT_was_not showntobeusefulandledtoadecreaseinthekappavalue (from 0.39to0.33), whichperhapscanbeexplainedbythe complexityoftheclassificationsystem,asdiscussedearlier.

Thus,ourstudydemonstratedthattheNeerclassification wasmorereproduciblewhenCTwith3Dreconstructionwas used,whichthereforejustifiesitsuseinclassifyingfractures oftheproximalextremityofthehumerus,whichiswhatitis mostusedforinoursetting.Nonetheless,inabsolutevalues, thereproducibilitystillremainslow.Thiswasnotobserved whentheAOclassificationwasused.

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177 Conclusion

CTwith3Dreconstructionimprovedtheintra-and interob-serverconcordancefortheNeerclassificationmethod.This wasnotobservedfortheAOclassificationsystem,inwhich onlyinterobserverconcordancewasseentoimprovewiththe useofCTwith3Dreconstruction.

Conflicts

of

interest

Theauthorsdeclarenoconflictsofinterest.

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