Rev. bras. ortop. vol.49 número5

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

Original

Article

Densitometric

study

of

the

clavicle:

bone

mineral

density

explains

the

laterality

of

the

fractures

夽

,

夽夽

Marcelo

Teodoro

Ezequiel

Guerra

_,

_Maria

_Isabel

_Pozzi

_,

_Gabriela

_Busin

_,

Lucas

Crestana

Zanetti

_,

_José

_Antônio

_Lazzarotto

_Terra

_Lopes

_,

_Vinícius

_Orso

b_{GrupodoOmbroeCotovelo,HospitalUniversitário,UniversidadeLuteranadoBrasil(ULBRA),Canoas,RS,Brazil} c_{HospitalUniversitário,UniversidadeLuteranadoBrasil(ULBRA),Canoas,RS,Brazil}

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Articlehistory: Received13June2013 Accepted19July2013 Availableonline16July2014

Keywords: Densitometry Bonefracture Physiopathology Clavicle

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Introduction:Epidemiologicalstudieshaveshownlateralityinclaviclefractures,suchthatthe leftsideismorefrequentlyfractured.Thepresentstudyhadtheaimofevaluatingwhether theclavicleonthedominantsideisdenserandthusexplainingthegreaterincidenceof fracturesonthenon-dominantside.

Materialsandmethods:Thiswasadescriptivestudyon52healthypatients,whowere clas-sifiedaccordingtoage,sexandwhetherthedominantornon-dominantsidewasaffected. Results:Theparticipantscomprised28women(53.8%)and24men(46.2%).Regardingthe dominantside,30wereright-handed(57.7%)and22wereleft-handed(42.3%).Themeanage was25years.Inthisstudy,itcouldbeseenthatthenon-dominantsidehadgreaterbone massthanthedominantside.Itwasalsoobservedthatthebonedensitywasgreaterinthe middleanddistalthirdsonthenon-dominantside,withastatisticallysignificant differ-ence.Inthewomen,thedensitywasalsogreateronthenon-dominantside;thisdifference wasnotsignificantinrelationtothedominantside,butthereweresignificantdifferences betweenthemiddlethirds(p<0.001)andthedistalthirds(p<0.006).

Conclusion:Variationsinbonedensity,towardhigherandlowerbonemass,mayhavebeen responsibleforthefractures.Accordingtothefindingsfromthisstudy,fracturesoccurmore inthemiddlethirdofthenon-dominantclavicle,asaresultofgreaterbonemineralmass, whichgivesrisetolowerflexibilityandfracturesintheregion.

©2014SociedadeBrasileiradeOrtopediaeTraumatologia.PublishedbyElsevierEditora Ltda.Allrightsreserved.

夽

Pleasecitethisarticleas:TeodoroEzequielGuerraM,IsabelPozziM,BusinG,CrestanaZanettiL,AntônioLazzarottoTerraLopesJ,Orso Vetal.Estudodensitométricodaclavícula:adensidademineralósseaexplicaalateralidadedasfraturas.RevBrasOrtop.2014;49(5):468–72. 夽夽

StudydevelopedattheUniversidadeLuteranadoBrasil,Canoas,RS,Brazil. ∗ _{Correspondingauthor.}

E-mail:gabibusin@hotmail.com(G.Busin).

http://dx.doi.org/10.1016/j.rboe.2014.07.002

Estudo

densitométrico

da

clavícula:

a

densidade

mineral

óssea

explica

a

lateralidade

das

fraturas

Palavras-chave: Densitometria Fraturaóssea Fisiopatologia Clavícula

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e

s

u

m

o

Introduc¸ão: Estudosepidemiológicosmostramumalateralidadenasfraturasdaclavícula, comoladoesquerdomaisfrequentementefraturado.Opresenteestudotemcomo finali-dadeavaliarseaclavículadoladodominanteémaisdensaeexplicar,dessaforma,amaior incidênciadefraturasnoladonãodominante.

Materialemétodos: Estudodescritivode52pacienteshígidos,classificadosquantoaidade, sexoeladodominanteounão.

Resultados: Fizerampartedesteestudo28mulheres(53,8%)e24homens(46,2%);emrelac¸ão aoladodominante,30eramdestros(57,7%)e22,canhotos(42,3%);aidademédiafoide 25anos.Nesteestudo,foipossívelconstatarqueoladonãodominantetevemaiormassa ósseaquandocomparadoaoladodominante.Tambémobservamosqueadensidadeóssea foimaiornosterc¸osmédiosedistaisnoladonãodominante,comdiferenc¸a estatistica-mentesignificativa.Nasmulheres,adensidadetambémfoimaiornoladonãodominante; essadiferenc¸anãofoisignificativaquandocomparadocomoladodominante,porémfoi significativamentediferenteentreosterc¸osmédio(p<0,001)edistal(p<0,006).

Conclusão:Asvariac¸õesdadensidadeóssea,tantocommaiorcomocommenormassaóssea, podemserresponsáveispelasfraturas.Deacordocomosachadosdesteestudo,asfraturas ocorremmaisnoterc¸omédiodaclavículanãodominante,emdecorrênciadeumamaior massamineralóssea,oqueacarretariaumamenorflexibilidadedaregiãoeasfraturas.

©2014SociedadeBrasileiradeOrtopediaeTraumatologia.PublicadoporElsevier EditoraLtda.Todososdireitosreservados.

Introduction

Changesintherapeuticmethodsforclaviclefractures have ledtoepidemiologicalstudiesconductedmorefrequently.1–3 Classically,conservativetreatmentwasusedwithexcellent results.However,somefracturepatternshavebeenshownto beproblematicwithconservativetreatment,independentof themanagementused.Thus,newstudieshaveemerged, out-liningtheepidemiologicalprofileandmanagementofclavicle fractures.4

Clavicularfractures accountforapproximately 5%ofall patientswithfracturesadmittedtoemergencyservices.5_Male childrenandadolescentsuptotheageof20yearsarethegroup mostlikelytosuffer thistypeoffracture,andits incidence decreaseswith increasingage.Amongfemalepatients, the incidenceisgreatestduringtheadolescentyearsand dimin-ishesinsubsequentdecades,butthenincreasesagaininold age.6,7

InanepidemiologicalstudyconductedinSweden,on535 fracturesoftheclaviclealone,greaterfrequencywasobserved ontheleftside(60.7%)thanontherightside(49.3%)andthis differencewasstatisticallysignificant.Itisknownthat differ-entbonedensitiesmaycausefractures.8–11 _{Pycnodysostosis} isasyndromecharacterizedbybonefragilityandfracturing duetodiffuselyincreasedbonedensity.Osteoporosis,onthe otherhand,isadisorder characterizedbydiminishedbone massandincreasedriskoffractures.12,13

Thisstudyhastheaimsofevaluatingclavicularbone min-eraldensitybetweenthedominantandnon-dominantsides andevaluatingbonemineralmassinthemiddleandlateral thirdsoftheclavicle,soastoascertainwhetherdifferentbone

mineraldensitiescouldexplaincertainepidemiological char-acteristicsoffracturesoftheclavicles.

Materials

and

methods

Thiswas across-sectionalstudy conductedintheimaging departmentofourhospitalbetweenMayandJune2007and betweenJanuaryandMay2012.Densitometricexaminations wereperformedonbothclaviclesinasampleof52patients, comprising24males(eightleft-handedand16right-handed) and 28 females (14 left-handed and 14 right-handed).The examinationswereperformedusingbonedensitometry appa-ratusandwereanalyzedbymeansoftheDualFemursoftware, adaptedfortheclavicle.

Alluniversitystudentsagedbetween20and30yearswho were in a healthy condition were eligible for inclusion in the study. Professional athletes, individuals with previous clavicularfractures(whether congenitalor not),individuals withosteometabolicdiseases,casesofbrachialplexusinjury, ambidextrousindividualsandcasesofanyorthopedic disor-derthataffectstheshoulderwereexcluded.

anotherwasstoredforsubsequentstudies.Thishadbeenlaid outintheconsentstatement.

Inthisstudy,thenonparametricWilcoxontestwasused, withasignificancelevelof5%.Toviewtheresultsobtained, boxplotgraphswereused.

This study was approved by our institution’s Research EthicsCommittee,underprotocolnumber2006-064H.

Results

Among the 52 patients who underwent the densitometry examination on the clavicle, 24 (46.2%) were male and 28 (53.8%)werefemale.Inrelationtothedominantside,30were right-handed(57.7%)and22wereleft-handed(42.3%)(Table1). Thepatientsanalyzedwerebetween20and30yearsofage (meanageof25years).

Amongthese52universitystudentswhounderwentthe examination,the bone mineral density ofthe claviclewas greater on the non-dominant side, i.e. among the right-handed individuals,the bone mineral density was greater in the left claviclethan in the right clavicle; whilein the left-handedindividuals,thedensitywasgreaterintheright claviclethanintheleftclavicle.Thisdifferencebetweenthe dominantand non-dominantsideswasstatistically signifi-cant(p<0.001),withgreaterdensityonthenon-dominantside (Table2).

Amongthemen,therewasastatisticallysignificant differ-encebetweenthedominantandnon-dominantsidesbothin themiddlethird(p=0.028)andinthedistalthird(p=0.010)of theclavicle,withgreaterdensityonthenon-dominantside (Table2).Therewasalsoastatisticallysignificantdifference between the middle and distal thirds, both on the domi-nantside(p=0.003)andonthenon-dominantside(p=0.002). Themiddlethird presentedhighervaluesin bothclavicles (Figs.1and2).

Inthewomen,thedominantsidehadgreaterdensity,but therewasnostatisticallysignificantdifferencebetweenthe dominantandnon-dominantsides.Therewasonlya differ-encebetweenthemiddlethirds(p=0.001)andbetweenthe distalthirds(p=0.006). Themiddlethirdspresentedhigher values(Table2andFigs.1and2).

In general,we can affirm that the clavicleon the non-dominant side presented significantly greater values than shownbytheclavicleonthedominantside,inthedistalthird (p=0.020)and that themiddle thirdpresentedsignificantly greatervaluesthanthedistalthirdinbothclavicles(p<0.001).

Table1–Characterizationofthesample.

Characteristics n=52

Sex–n(%)

Male 24(46.2)

Female 28(53.8)

Dominance–n(%)

Right-handed 30(57.7)

Left-handed 22(42.3)

8

7

5

4

3

3 2

1

0

–1

Male

Dominant middle

14 19

21

Non-dominant middle Female

Sex

Bone mineral density (g/cm

2) 6

Fig.1–Evaluationofbonemineraldensityrelatingtothe middlethirdoftheclavicle,accordingtothepatient’ssex.

Discussion

It hasalready been well establishedthat there isa strong relationshipbetweenbonemineraldensityandthedominant side.Bonemassvariesaccordingtouse.Boneisdeposited pro-portionallytothecompressiveloadthatithastobear,andthis iswhyathleteshavegreaterbonemassthanpeoplewhodo notpracticeexercise.Thelattertendtolosebonemass.14–16

Thepresentstudyfoundsignificantdatafromasampleof 52individualswhounderwentexamination.Sincethestudy groupwashomogenous,theresultsfoundwouldnotchange withalargerorsmallersamplethaninthepresentstudy.This wasprovenwhenweaddednewcasestothestudy,giventhat thefirstsamplewasobtainedin2007andthesecond,in2012. Inaprospectivestudyinvolving213patients,densitometry wasperformedontheradiusandulnaofbothforearms.Itwas observedthatthedominantforearmhadgreaterbonemass andalsogreaterbonearea.Onepossibleexplanationforthe greaterbonemassinthedominantlimbwasitsgreateruse. Thedifferencesintheulnawerestatisticallysignificant.17

Table2–Evaluationofbonemineraldensityaccordingtothedominantside.

Bonemineraldensity Dominantmedian(p25–p75) Non-dominantmedian(p25–p75) pa

Men(n=24)

Middle 1.01(0.80–1.10) 1.14(1.02–1.54) 0.028

Distal 0.40(0.17–0.65) 0.71(0.51–1.06) 0.010

pa _{0.003 0.002}

Women(n=28)

Middle 0.99(0.73–1.11) 1.01(0.78–1.15) 1.000

Distal 0.56(0.17–0.69) 0.59(0.42–0.73) 0.530

pa _{0.001 0.006}

Total(n=52)

Middle 1.01(0.79–1.09) 1.07(0.93–1.24) 0.134

Distal 0.49(0.17–0.69) 0.64(0.45–0.92) 0.020

pa _{<0.001 <0.001}

a _{ValueobtainedthroughWilcoxontest.}

8

7

5

4

3

2

1

0

–1

Male

14 19

21

Female

Sex

Bone mineral density (g/cm

2) 6

Dominant distal Non-dominant distal

Fig.2–Evaluationofbonemineraldensityrelatingtothe distalthirdoftheclavicle,accordingtothepatient’ssex.

OurfindingsweresimilartothoseofGumustekinetal.,14 i.e.thebonemineraldensityoftheclaviclewasgreateron

thenon-dominantthanonthedominantside.Theclavicleon thedominantsidepresentedlowerbonemineralmassthan shownbytheclavicleonthenon-dominantside.This differ-encewasstatisticallysignificant.

Fracturesoftheclaviclearestatisticallymorefrequenton theleftsideandoccurmostofteninthemiddlethirdoftheleft clavicle(81%),followedbythelateralthird(17%)andmedial third(2%).12

It could be seen that greater bone density on the non-dominantsidecouldleadtogreaterbonefragilitythroughloss offlexibility,18–20_{sincefracturesoftheclavicleoccurmost} fre-quentlyinthemiddlethird,preciselywherethebonedensity isgreatest,bothinthe dominantandinthenon-dominant clavicle.

Conclusion

Theclavicleonthenon-dominantsideisdenserthanthe clav-icleonthedominantside.Likewise,themiddlethirdofthe clavicles, bothon the dominantand onthe non-dominant side, isdenserthan thedistalthird.Thus, theoccurrences ofclavicularfracturesmoreontheleftside,asfoundinthe presentstudy,couldbeduetogreaterbonemineraldensityon thenon-dominantside,whichwoulddiminishboneflexibility and,hypothetically,increasethepropensitytofractures.

Conflicts

of

interest

Annex

1.

Questionnaire:

Densitometric

study

on

the

clavicle:

does

bone

density

explain

the

laterality

of

fractures?

Name: _______________________________________ Reg. no.: _______________

Date of birth: ____________________________ Age: _________________

Sex: ( ) F ( ) M Course: ( ) Medicine ( ) Other:_________________

Handedness: ( ) Right-handed ( ) Left-handed ( ) Ambidextrous

Do you have any chronic disease?

( ) Yes: ____________________________________ ( ) No

Are you a professional athlete?

( ) Yes ( ) No

Have you ever suffered a clavicular fracture? (Including fractures during childbirth)

( ) Yes ( ) No

Have you ever undergone any surgical intervention in the clavicle or shoulder?

( ) Yes ( ) No

Do you have any upper-limb deformity?

( ) Yes ( ) No

Do you have or have you had any injury to the brachial plexus?

( ) Yes ( ) No

Do you have any orthopedic disease of the shoulder?

( ) Yes ( ) No

Do you have any osteometabolic disease?

( ) Yes ( ) No

Do you have any type of restriction on upper-limb movement?

( ) Yes ( ) No

For the researcher to fill out

Was the volunteer selected for the study in accordance with the criteria?

( ) Yes ( ) No

I agree with all the information expressed in this form.

____________________________

Signature of the research subject

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