Rev. bras. ortop. vol.50 número1

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

Original

article

Radiographic

study

on

the

anatomical

characteristics

of

the

proximal

femur

in

Brazilian

adults

夽

Tércio

Henrique

Soares

de

Farias

a,∗

,

Vinícius

Quadros

Borges

a

,

Eduardo

Soares

de

Souza

a

_,

_Natália

_Miki

b

_,

_Fernando

_Abdala

a

a_Hospital_Municipal_Dr._Cármino_Caricchio,_São_Paulo,_SP,_Brazil

b_Departamento_de_Ortopedia_e_{Traumatologia,}_Faculdade_de_Medicina,_Universidade_Federal_de_São_Paulo_(Unifesp),_São_Paulo,_SP,_Brazil

a

r

t

i

c

l

e

i

n

f

o

Articlehistory:

Received30October2013 Accepted5December2013 Availableonline18February2015

Keywords:

Femur/anatomyandhistology Femur/physiology

Radiography

a

b

s

t

r

a

c

t

Objective:ToascertainthegeometryofthefemurintheBrazilianpopulationbymeansofa radiographicstudyandtocorrelatethevalueswithregardtosexandright/leftside.

Methods:Five hundred anteroposterior radiographs of the pelvis of skeletally mature patients(250ofeachsex)whodidnotpresentanyosteoarthrosis,fracturesortumoralor infectiouslesionswereanalyzed.Thelengthandwidthofthefemoralneck,lengthofthe femoralaxis,neck-shaftangleandfemoraloffsetweremeasured.

Results:Thefollowingmeanswereobserved:36.54mmforthelengthofthefemoralneck; 37.48mmforthewidthofthefemoralneck;108.42mmforthelengthofthefemoralaxis; 130.47◦_for_the_neck-shaft_angle;_and_44.4_mm_for_the_femoral_offset.

Conclusion:Themeanvaluesforthemainmeasurementsontheproximalfemurin Brazil-iansdiffered fromthose ofprevious studies.It could also beshown thattherewas a statisticallysignificantmeandifferencebetweenmenandwomenforallthevariables,both ontheleftandontherightside,andthatthemenhadgreatermeansthanthewomen.

Estudo

radiográfico

dos

aspectos

anatômicos

do

fêmur

proximal

dos

adultos

brasileiros

Palavras-chave:

Fêmur/anatomiaehistologia Fêmur/fisiologia

Radiografia

r

e

s

u

m

o

Objetivo:Verificarageometriadofêmurdapopulac¸ãobrasileirapormeiodeestudo radio-gráficoecorrelacionarosvaloresquantoaosexoeaoladodireito/esquerdo.

Métodos:Foram analisadas 500 radiografias anteroposteriores de bacia de pacientes esqueleticamentemaduros,250decadasexo,semapresenc¸adeosteoartrose,fraturase

夽

WorkdevelopedatDr.CárminoCaricchioMunicipalHospital,SãoPaulo,SP,Brazil. ∗ _{Corresponding}_author_.

E-mail:terciohs@yahoo.com.br(T.H.S.deFarias).

http://dx.doi.org/10.1016/j.rboe.2015.02.001

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lesõestumoraisouinfecciosas.Forammensuradososvaloresdocomprimentoedalargura docolodofêmur,doeixofemoral,doângulocolodiafisárioedooffsetfemoral.

Resultados: Observou-se uma média de 36,54mm do comprimento do colodo fêmur, 37,48mmdalarguradocolodofêmur,108,42mmdocomprimentodoeixofemoral,130,47◦ doângulocolodiafisárioe44,4mmdooffsetfemoral.

Conclusão: Osvaloresmédiosdasprincipaismedidasdofêmurproximaldosbrasileiros diferemdetrabalhosprévios.Foipossívelevidenciartambémqueexistediferenc¸amédia estatisticamentesignificanteentrehomensemulheresparatodasasvariáveis,tantodolado esquerdoquantododireito,equeoshomenstiverammédiamaiordoqueasmulheres.

Introduction

Thefemoralheadprojectssuperomediallyand slightly for-wardswhenitarticulateswiththeacetabulum.Theheadand neckformanangleof115–140◦_(mean_of₁₂₆◦₎_with_the_long

axisofthebodyofthefemur.1_The_angle_is_greatest_at_birth_and decreasesgradually,fromaround150◦_in_newborns_to_around

133◦_at₁₅_years_of_age._It_is_smaller_in_women_because_of_the

widthofthepelvisandgreaterobliquityofthebodyofthe femur.2,3

Thefemoral head and the acetabulum ofthe hip bone growindependentlybutinsuchawaythattheydevelop con-gruently. This mechanism is influenced by forces that act externallyintheseareas.Themostimportantoftheseare bodyweightandmuscletensionforces,whichneedtohave magnitudesanddirectionsforappropriateinteractions.Any changetothecompressionforcesoranyjointincongruence willleadtodeformities.Thepressure,archingandshearing stressestowhichthefemurissubjectedareimportantin rela-tiontofractureproductionandalsodevelopmentofvarious pathologicalprocesses.4–6

Radiographicstudieshavesuggestedthatthehipaxisand thefemoralneckarebecoming longer.These changesmay increasetheriskoffracturesthroughtheincreasedlengthof theleverarm.Othernon-geometricfactorsthatmight predis-posetowardfemoralfractureshavebeenwidelydebatedin theliteratureandtheseinclude:advanced age,femalesex, osteoporosis, genetic factors (such as Colia1 Sp1 polymor-phism),smoking,alcoholabuse, previousfracturesandlow estrogenlevels.Thus,newanalysesonhowthegeometric pat-ternmightinfluencepathologicalconditionsofthefemurare pertinent.7–10

AccordingtoAmericanstatistics,morethan 250,000hip fractures occur every year and this number is expected to approximately double over the next 30 years.4 _The treat-mentformostfemoralfractures issurgical. Therefore,it is importanttoknowthegeometryofthefemur,sincealarge proportionofimplantscomeinstandardsizes,selectedfrom arangesupplied bymanufacturers.For example,thePFN®

short nail (AO/ASIF) can provide inclinations of 125◦_, ₁₃₀◦

or135◦ _between_the_screws_of_the_neck_and_the_axis_of_the

intramedullarynail. Choosingtheseimplants wronglymay giverisetoalterationstotheanatomyofthehipjoint.11,12

Becauseofthe clinicalimportanceofthemorphometric aspectsof the proximalfemur, a wide-ranging surveywas

conductedinordertoprovidedataonthegeometryoffemoral bonesamongBrazilians.

Theaimsofthepresentstudyweretoascertainthefemoral geometryoftheBrazilianpopulationbymeansofradiographic evaluationsandcorrelatetheparameterswithregardtosex andright/leftside.

Materials

and

methods

An observational cross-sectional study was conducted, in whichpatientswhohadundergoneradiographyonthepelvis inanteroposterior(AP)viewwereevaluated.Thepopulation comprisedof250menand250womenwhowereattendedat theemergencyserviceorintheoutpatientclinicorwardsof theorthopedicsandtraumatologyservice.Noneofthe radio-graphicimageswasproducedforoccupationalreasons.The APradiographsofthepelvisincludedinthisstudywerefrom skeletallymaturepatientswhodidnotpresentosteoarthrosis, fracturesortumoralorinfectiouslesions.

Toobtainthe radiographs,theincident raywasdirected along themedianline, justabovethepubicsymphysisand thefeetwererotatedinternallyataround15◦_._The_patient_was

positionedindorsaldecubitusandtheampoulewasonemeter fromtheframe.Thedegreeofmagnificationobtainedthrough theradiographicmethodwascorrected.

Thefemoralmeasurementsanalyzedwereasfollows:

Offset–distancebetweenthecenterofrotationofthehip andalinetracedoutperpendicularlythroughthecenterof thefemoralshaft(Fig.1).

WFN–widthofthefemoralneck,i.e.thedistanceatthe mid-pointofthefemoralneck,perpendiculartoitsaxis(Fig.2). LFA –lengthofthe femoralaxis,i.e.thestraight-line dis-tancebetweentheextremitiesofthegreatertrochanterand femoralhead,inthefrontalplane(Fig.2).

LFN–lengthofthefemoralneck,i.e.thedistancein mil-limetersbetweenthelowerregionofthefemoralheadand thebaseofthegreatertrochanter(Fig.2).

NSA–neck-shaftanglecreatedbetweentheneckandshaft, which was measured in the frontal plane by means of goniometry(Fig.3).

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Offset

Fig.1–Measurementoftheoffset.

softwareusedinthisstatisticalanalysiscomprisedSPSSV17, Minitab16andExcelOffice®_2010._The_significance_level_was

setat0.05(5%)andalltheconfidenceintervalsconstructed overthecourseofthestudywere95%.

Results

Therightandleftsideswerecomparedforallthevariables

(Table1).Thesecomparisonsweremadeseparatelyforeach

genderandforbothtogether(general).Here,thepaired Stu-dent’sttestwas used,giventhatthedatawere paired,i.e. thesamesubjectprovidedthestudylimbandhisorherown control.

Itcouldbeseenthatsomeofthecomparisonsbetweenthe sideswerestatisticallysignificant.Theresultsfrom measur-ingthewidthofthefemoralneckandoffsetpresentedmean differencesbetweenthesidesforbothsexesandingeneral.

Incomparingthelengthsofthefemoralneck,therewas onlyastatisticallysignificantdifferenceinthegeneral com-parison,withameanof36.65ontheleftside,versus36.44on therightside(p=0.048).

WFN

LFA

LFN

Fig.2–Widthofthefemoralneck(WFN);lengthofthe femoralaxis(LFA);lengthofthefemoralneck(LFN).

NSA

Fig.3–Neck-shaftangle(NSA).

Ontheotherhand,regardingthelengthofthefemoralaxis, therewasonlyastatisticallysignificantresultfromcomparing themen,suchthatthemeanfortheleftsidewas114.06,versus 114.39ontherightside.

Lastly,regardingtheneck-shaftangle,therewere statisti-callysignificantdifferencesbetweenthesidesforthewomen and ingeneral.Itneedstobehighlightedthatthe leftside alwayshadagreatermeanthantherightside.

Thesexeswerethencomparedforallthevariables.These comparisonsweremadeontherightsideandontheleftside. TheANOVAtestwasusedhere(Table2).

It could be seen that bothfor the left side and for the rightside,therewerestatisticallysignificantmeandifferences betweenthemenandwomenforthefivevariables.For exam-ple,withregardtotheoffsetontherightside,themeanforthe womenwas41.97,versus47.57forthemen,andwithregard totheoffsetontherightside,themeanforthewomenwas 41.53,s46.54forthemen(p<0.001).Itcouldbeseenthatforall thevariablesonbothsides,themenhadgreatermeansthan thewomen.

Discussion

Several aspectsof the geometry of the femoralneck have beenfoundtoinfluencetheriskofhipfractures.Studieshave correlatedgreaterlengthofthefemoralneckandlower val-ues forthe neck-shaft angle with greater incidenceof hip fractures.8,13,14

Population-basedstudieshaveshownthat,overtime,there hasbeenanincreaseinthelengthofthefemoralneckand adecreaseinthewidthoftheneckinthefemalepopulation andhavecorrelatedthesechangeswithanincreaseintherisk offractures.Thismayhavecontributedtowardtheone-third increaseintheincidenceofhipfractures.15,16

Fewstudiesevaluatingthegeometryoftheproximalfemur havebeenconductedinBrazil.17,18_Because_of_the_importance ofthemorphometricevaluation,alargersamplewasrecruited forthepresentstudy(250radiographsfrommenand250from women)thanwasusedinpreviousstudies.Moreover, mea-surementsofthefemoraloffsetwereincludedinthepresent study.

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Table1–Comparisonofthevariableswithregardtotherightandleftsides.

Female Male General

Left Right Left Right Left Right

Lengthofthefemoralneck

Mean 34.68 34.55 38.54 38.27 36.65 36.44

Median 34.00 33.00 38.27 38.20 36.10 36.00

SD 5.30 5.42 4.72 4.50 5.37 5.31

Min. 27.40 25.00 30.00 27.00 27.40 25.00

Max. 49.72 48.50 46.82 47.76 49.72 48.60

p-Value 0.355 0.056 0.048

Widthofthefemoralneck

Mean 34.81 34.55 40.61 40.16 37.71 37.25

Median 35.00 34.72 40.00 40.00 38.00 37.00

SD 3.39 2.98 4.24 3.71 4.81 4.45

Min. 24.20 28.60 31.00 32.00 24.20 28.60

Max. 41.16 41.13 51.15 49.36 51.15 49.36

p-Value <0.001 0.001 <0.001

Lengthofthefemoralaxis

Mean 102.48 102.68 114.06 114.39 108.27 108.57

Median 104.30 104.00 115.00 1115.00 107.46 108.00

SD 5.91 6.19 7.79 7.23 9.01 8.93

Min. 88.00 85.40 97.00 97.70 88.00 85.40

Max. 120.00 118.00 132.66 134.00 132.66 134.00

p-Value 0.519 0.047 0.051

Neck-shaftangle

Mean 129.54 128.42 132.38 131.53 130.96 129.98

Median 129.90 128.10 133.40 132.00 130.00 130.00

SD 9.16 5.09 9.39 5.31 9.37 5.43

Min. 120.00 116.70 120.00 118.80 120.00 116.70

Max. 143.60 144.10 146.00 150.00 146.00 150.00

p-Value 0.023 0.103 0.006

Offset

Mean 41.53 41.97 46.54 47.57 44.03 44.77

Median 41.31 42.55 47.00 48.60 44.60 45.00

SD 7.11 6.76 8.33 8.14 8.13 7.98

Min. 30.00 30.00 30.10 32.00 30.00 30.00

Max. 69.10 66.90 68.80 69.13 69.10 69.13

p-Value 0.002 <0.001 <0.001

foundthatthemeanfortherightsidewas24.9mmandfor theleftside,24.3mm.Duthieetal.15_analyzed_Scottish popu-lationsattwodifferenttimesandalsofoundgreaterlengthsof thefemoralneck:34.9mmand38.3mmformenand32.5mm and35mmforwomen.Theyexplainedthisdifferenceinterms ofbetter nutritionduring childhood and changes in living standardsingeneral.

Regardingthe lengthofthefemoralaxis,O’Neillet al.16 evaluatedthis infemalepopulations in1950and 1990and foundvaluesof124mmand136.2mm,respectively.Ina simi-larstudy,Reidetal.19_found_values_of_124.0_mm_and_130.5_mm, respectively. Thevalues forthe length ofthe femoral axis foundinthepresentstudyweresmallerthanthoseofthe stud-iesbyO’Neilletal.16_and_Reid_et_al.19_This_difference_can_be explainedbythedifferentmethodologiesused,giventhatin thepresentstudy,thepelvicstructurewasnotincludedinthe analysisofthelengthofthefemoralaxis.Norwasthisdonein thestudybyMourãoandVasconcellos,17_who_found_lengths of92.1mmfortherightsideand92.0mmfortheleftside.

Higher valuesfor the width ofthe femoralneck inthe Brazilian population were found here, in comparison with

thestudybyMourãoandVasconcellos,17_whose_values_were 26.7mm(±3.1)fortherightsideand26.3mm(±3.3)forthe leftside.NeitheroftheBrazilianstudiesfoundanysignificant differencesbetweenthesides.O’Neilletal.16_observed_that therewasapositivecorrelationbetweenthelengthandwidth ofthefemoralneckandfoundmeasurementsof36.6mmand 39.1mmforthewidthsin1950and1990,respectively.Using similarmethodology,Reidetal.19_found_mean_values_for_the widthofthefemoralneckof38.1mmfromradiographs per-formedonwomenin1950and38.6mmin1990.Theytherefore concludedthatthewidthofthefemoralneckhadincreased overthecourseoftime.IntheradiographicstudybyCheng etal.,4 _the_mean_values_found_for_the_length_of_the_femoral neckforbothsexeswere35.1mmfortheleftsideand35.5mm fortherightside.

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Table2–Comparisonofthevariablesinrelationto gender.

Left Right

Female Male Female Male

Lengthofthefemoralneck

Mean 34.68 38.54 34.55 38.27

Median 34.00 38.27 33.00 38.20

SD 5.30 4.72 5.42 4.50

Min. 27.40 30.00 25.00 27.00

Max. 49.72 46.82 48.50 47.76

p-Value <0.001 <0.001

Widthofthefemoralneck

Mean 34.81 40.61 34.55 40.16

Median 35.00 40.00 34.72 40.00

SD 3.39 4.24 2.98 3.71

Min. 24.20 31.00 28.60 32.00

Max. 41.16 51.15 41.13 49.36

p-Value <0.001 <0.001

Lengthofthefemoralaxis

Mean 102.48 114.06 102.68 114.39 Median 104.30 115.00 104.00 1115.00

SD 5.91 7.79 6.19 7.23

Min. 88.00 97.00 85.40 97.70

Max. 120.00 132.66 118.00 134.00

p-Value <0.001 <0.001

Neck-shaftangle

Mean 129.54 132.38 128.42 131.53 Median 129.90 133.40 128.10 132.00

SD 9.16 9.39 5.09 5.31

Min. 120.00 120.00 116.70 118.80 Max. 143.60 146.00 144.10 150.00

p-Value <0.001 <0.001

Offset

Mean 41.53 46.54 41.97 47.57

Median 41.31 47.00 42.55 48.60

SD 7.11 8.33 6.76 8.14

Min. 30.00 30.10 30.00 32.00

Max. 69.10 68.80 66.90 69.13

p-Value <0.001 <0.001

theleftside.Silvaetal.18_found_values_of_122.5◦_for_the_right

sideand125.6◦_for_the_left_side_and_explained_this_difference

betweenthe limbs withthe hypothesis that the dominant limb(theonethatwouldbesubjectedtomoreweight-loading) mighthaveasmallerneck-shaftanglethanthecontralateral limb.Inamulticenterprospectivestudyamongwomenover theageof60years,usingDEXA,Faulkneretal.6_found_that_the neck-shaftangleofthecontrolgroupwas126◦_._Cheng_et_al.9 foundameanvalueof125◦ _in_a_radiographic_study _on_the

proximalfemur.

Thevaluesfoundfortheoffsetinthepresentstudywere 44.03mmfortheleftsideand44.77mmfortherightside.We didnotfindany reportsinthisregard inthe Brazilian spe-cializedliterature.18,20_Ferris_et_al.21_analyzed_the_{contralateral} femurofpatientswithsubcapitalfractures,transtrochanteric fracturesandosteoporosisandfoundmeanvaluesof43mm (±0.4),38mm(±0.6)and41mm(±0.6),respectively.This differ-encecanbeattributedtothemethodologyused,amongother reasons.

Conclusion

Themeanvaluesofthemainmeasurementsoftheproximal femuroftheseBraziliansdifferedfromthevaluesfoundin previous studies.Therewasastatisticallysignificant mean differencebetweenthemenandwomenforallthevariables, bothontheleftsideandontherightside.Themenpresented highervaluesthanthoseofthewomen.

Conflicts

of

interest

Theauthorsdeclarenoconflictsofinterest.

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