SOCIEDADE BRASILEIRA DE ORTOPEDIA E TRAUMATOLOGIA
w w w . r b o . o r g . b r
Original
Article
Radiographic
evaluation
of
cementation
technique
using
polished,
conical,
triple-tapered
femoral
stem
in
hip
arthroplasty
夽
Ademir
Antônio
Schuroff,
Mark
Deeke,
Marco
Antônio
Pedroni,
Fernando
Silva
Lupselo
∗,
Rodrigo
Ernesto
Kunz,
Alexandre
Matos
Lima
HospitalUniversitárioCajuru,Curitiba,PR,Brazil
a
r
t
i
c
l
e
i
n
f
o
Articlehistory:
Received23November2016 Accepted26January2017 Availableonline5September2017
Keywords: Hiparthroplasty Bonecement
Cementation/methods Hipprosthesis
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b
s
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r
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c
t
Objective:Toradiographicallyevaluatethequalityofcementationandimplantation tech-niqueusingapolished,triple-taperedfemoralstemintotalhiparthroplasty(THA). Method:Retrospectivestudy withradiographicevaluationof86 hipsin83 patientswho underwenttoprimaryTHAwiththetriple-taperedcementedfemoralstemC-Stem(DePuy Orthopedics,Warsaw,Indiana).Caseswithatleastone-yearoffollow-upwereincluded, anddatarelatedtopreoperative,immediatepostoperative,andlatepostoperative radio-graphicevolutionwererecorded.Thisstudyanalyzed,amongothers,theproximalfemoral anatomy,thequalityofcementationasdescribedbyBarrack,andtheimplant position-ing.CementationwasalsoevaluatedandquantifiedintheGruenzoneswithone-yearof follow-up.
Results:Themeanagewas62.85years.ProximalfemoralanatomicalconformationwasDorr typeAin34(39.53%)cases,typeBin52(60.46%),andnotypeCcaseswerefound.Five (5.81%)casesweredefinedastypeAbyBarrack’s cementationclassificationsystem,46 (56.49%)typeB,27(31.40%)typeC,andeight(9.30%)typeD.Thegreatestcementmantle thicknesswasobservedinzonesfour(15.53mm)and11(15.64mm),andthesmallestin zonenine(3.51mm).Positioninginvaruswasobservedineight(9.3%)cases,valgusin25 (29%),forwarddeviationintwo(5%),andbackwarddeviationin55(63.95%).
Conclusions:TheC-Stemfemoralsystempresentedsatisfactoryresultsrelatedto cementa-tionpattern,positioning,osteolysis,andstressshieldingwithregardtoliteraturereferring todouble-taperedor triple-taperedmodels,demonstrating tobea safemethod,with a predictableandreliablecementingpattern.
©2017PublishedbyElsevierEditoraLtda.onbehalfofSociedadeBrasileiradeOrtopedia eTraumatologia.ThisisanopenaccessarticleundertheCCBY-NC-NDlicense(http:// creativecommons.org/licenses/by-nc-nd/4.0/).
夽
StudyconductedatHospitalUniversitárioCajuru,Curitiba,PR,Brazil. ∗ Correspondingauthor.
E-mail:[email protected](F.S.Lupselo). http://dx.doi.org/10.1016/j.rboe.2017.08.019
Avaliac¸ão
radiográfica
da
técnica
de
cimentac¸ão
com
haste
femoral
cônica
polida
e
tripla
cunha
em
artroplastia
do
quadril
Palavras-chave: Artroplastiadequadril Cimentoósseo Cimentac¸ão/métodos Prótesesdequadril
r
e
s
u
m
o
Objetivo: Avaliarradiograficamenteaqualidadedatécnicadecimentac¸ãoeimplantac¸ãode hastesfemoraispolidasetriplacunhaemartroplastiastotaisdoquadril(ATQ).
Método: Estudoretrospectivocomavaliac¸ãoderadiografiasde86quadrisem83pacientes submetidos à ATQ com componente femoral cimentado polido em tripla cunha C
-Stem(DePuyOrthopaedics,Varsóvia,Ind.).Incluímoscasoscompelomenosumanode seguimento,foramregistradosdadosrelacionadosàevoluc¸ãoradiográficapré-operatória, pós-operatóriaimediataepós-operatóriatardia.Avaliamos,entreoutrosdados,aanatomia dofêmur,aqualidadedacimentac¸ãosegundodescritoporBarrackeoposicionamentoda haste.Acimentac¸ãotambémfoiavaliadaequantificadaemcadazonadeGruencomum anodeseguimento.
Resultados: Aidademédiafoide62,85anos.Aconformac¸ãodofêmurproximalfoidotipo AdeDorrem34(39,53%)casos,tipoBem52(60,46%)enãoforamobservadoscasosdotipo C.Cinco(5,81%)casosforamdefinidoscomotipoAsegundoaclassificac¸ãodecimentac¸ão deBarrack,46(56,49%)tipoB,27(31,40%)tipoCeoito(9,30%)tipoD.Amaiorespessura médiadomantofoiobservadanaszonas4(15,53mm)e11(15,64mm),amenorfoinazona 9(3,51mm).Foiobservadoposicionamentoemvaroemoito(9,3%)casoseemvalgoem25 (29%).
Conclusão: AhastefemoralC-Stemapresentouresultadossatisfatóriosquantoaopadrão decimentac¸ão,posicionamento,àpresenc¸adeosteóliseestressshielding,tantoemrelac¸ão àliteraturareferenteaosmodelosemduplacunhaquantoreferenteaomesmomodelode implante,mostrou-seummétodoseguroecompadrãodecimentac¸ãoprevisíveleconfiável. ©2017PublicadoporElsevierEditoraLtda.emnomedeSociedadeBrasileirade OrtopediaeTraumatologia.Este ´eumartigoOpenAccesssobumalicenc¸aCCBY-NC-ND (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Introduction
JohnCharnley was responsible forthe success inthe evo-lution of cemented total hip arthroplasty (THA). During years of study, changes in prosthetic models have been madetodecrease theincidenceoffailuressuchas loosen-ing,wear, stemruptures,andstress shielding.Single-plane simple-shapedfemoralstemshavebeenreplacedbybiconic or triconic forms, and porous stems bypolished versions; these changes allow better distribution of axial load and better adaptation or accommodation within the cement mantle.1
The concept of conical and polished rods is based on the theory that smoothsurfaces with double(two-way) or triple(three-way)taperingmaintainalessrigidrelationship betweenimplantandcement,allowingsecondarymigration andstabilization,withoutcreatingexcessivestress.2
Cementedfemoralcomponentspresentsomeadvantages inrelationtothecementlessones,suchasbettertransmission ofloadsintheproximalfemur(greatersimilaritybetweenthe cementandthe boneelasticitycoefficient),3,4 whichallows
itsremodeling.Boneresorptionsecondarytostressshielding leadstoadecreaseincementlessprosthesissurvival,5,6
partic-ularlyatthecalcarlevel.7Althoughitoccursmorecommonly
incementlessimplants,boneresorptionhasalsobeen demon-stratedincementedstems,8,9withgreaterlossinGruenetal.
zones1and7of.10Anotheradvantageisthelowrateoffemoral
fracturesduringsurgery(around 1%incementedand 6.6%
innon-cementedreconstructions).11Nonetheless,therateof
satisfactory resultsisdirectlyproportionaltothequalityof thecementingtechnique,suchasthemaintenanceofamean cementmantlethicknessbetween2and4mm,whichavoids bothbrittlenessandexcessivestress.12
Thisstudyaimedtoevaluatethequalityofthe cementa-tionandimplantationtechniquesoftheC-Stemfemoralstem (DePuyOrthopedics,Warsaw,Indiana).Itisaconical,polished stem witha wedge shape, made of nitrogenated stainless steel,inwhichthedistalmigrationwithinthecementmantle ispredicted,withsecondarystability.13
Material
and
methods
Thiswasaretrospectivestudythatassessedradiographsof 86hipsin83patientswhounderwenttotalhiparthroplasty with the C-Stem cemented femoral component. The sam-plewas selectedbysixorthopedicsurgeonsspecializingin hipsurgeryduringtheirtrainingstage.Consecutivepatients whoattendedoutpatientfollow-upvisitsfromJanuary2010to March2015wereincluded,providedtheyhadaminimumone yearfollow-up.
Table1–Surgicalandradiographicdata.
Operatedside
Typeofarthroplasty(cemented/hybrid) Stemsize
Typeofcementrestrictor(bone/synthetic) Anatomyoftheproximalfemur
Thicknessofthecementmantle Femoralosteotomylevel
Alignmentofthefemoralcomponent
Cementationqualityintheimmediatepostoperativeperiod Radiographicfindingsofcementationwithatleastone post-operativeyear
15◦internalrotation,andlateral,withdisclosingoftheentire femoralstem.
Atotalof907THAswere performed;in437,theC-Stem cementedfemoralcomponentwasused.Ofthepatients,98 wereexcludedduetoinadequateradiographicexamination, 113 due to previous surgery in the assessed hip, 130 due toinadequate outpatientfollow-up, and 10 due tomanual cementation. Data such as gender, age, preoperative diag-nosis,andfollow-upperiodwerecollectedbyreviewingthe medical charts. The radiographic analysis was performed with the Agfa HealthCare Viewer imaging system, where data related tothe surgery and the preoperative, immedi-ate postoperative (up to two postoperative days), and late postoperative(oneyearoffollow-up)periodswerecollected (Table1).
In the preoperative radiography, the proximal femoral anatomywasevaluatedusingtheDorretal.classification.14In
theimmediatepostoperativeperiod,thequalityofthe cemen-tationwas assessedaccording tothe method described by Barrack et al.15 Afterone year offollow-up, the quality of
thecementationwasevaluatedandquantifiedineachzone describedbyGruenetal.10Concomitantly,theratiobetween
cortex,cement,andstemthicknessinzones2and6onthe frontalradiographywerecalculated,aswellastheratiosin zones9and13 onthelateral radiography.Aspectssuchas cementmantlethickness,presenceofradiolucency(defined asthe presence ofa radiolucentline adjacent tothe scle-roticlineevaluatedintheGruenzones).10 Boneresorption,
cementfractures andbubbles,and stemfracture or migra-tionwerealsorecorded.Anotherrelevantvariablemeasured inthestudywasthealignmentdegreeofthefemoral com-ponent,inordertoobservethepresenceofvarus/valgusor antecurvatum/recurvatumpositioning.
Surgicaltechnique
The posterolateral surgical approach (Kocher-Langenbeck) was used in all cases, with the patient placed in lateral decubitus position using anterior and posterior position-ers.Medium-viscositySmartsetbonecement(EnduranceMV, DePuyInternational,Blackpool,England)wasintroducedina retrogradefashionwithapistol,pressurizedandrestrictedby asyntheticorabonepluginthecanal.Thefemoralstems wereinsertedusingadistalcentralizer.Pulselavageor vac-uummixingwerenotused.
Results
Atotalof86radiographsofprimaryTHAsin83patientswith C-Stemfemoralcomponentwerereviewed;31hips(36.05%)were frommalepatientsand55(63.95%),fromfemalepatients.The meanagewas62.85(23–86)years.
BasedontheclassificationbyDorretal.,1434(39.53%)
con-formationsofthe proximalfemurwereofthenormaltype (typeA);52(60.46%)oftheconicaltype(typeB);no conforma-tionswereclassifiedasthecylindricaltype(TypeC).According totheclassificationbyBarracketal.,15five(5.81%)caseswere
classifiedastypeA;46(56.49%),astypeB;27(31.40%),astype C;andeight(9.30%),astypeD.
Thethickestcementmantlemeanwasobservedinzones 4and11,15.53mm(0–74)and15.64mm(0–73),respectively, whilethelowestmeanwasobservedinzone9,3.51mm(0–10; Fig. 1). Ahigherradiolucency indexwas observedinzones 2and10in52(60.47%)casesand50(58.14%) cases, respec-tively;thelowestindexwasobservedinzone14,in16cases (18.60%;Fig.2).Amongtheareaswherestressshieldingwas observed,theincidencewashigherinzones1and14,with23 hips(26.74%)and12hips(13.95%),respectively,andalower incidencewasfoundinzones2and 13,withonlytwohips
Ant
(9,1) 1 (6,9) 8
(3,5) 9
11
(5,8) 10 12 (5,0) 13 (6,6) 14 (7,5)
(15,6)
7 (6,3)
6 (5,4)
5 (4,8)
(15,5) (4,7) 2
(4,9) 3
4
Post
Fig.1–Meanthicknessofthecementmantleineach
Gruenzone(mm).
Ant
(25,5) 1 (23,2) 8
(43,0) 9
(58,1) 10
(29,0) (60,4) 2
(50,0) 3 5(39,5) 12 (45,3)
13 (44,1) 14 (18,6)
6 (55,8) 7 (51,1)
(32,5)
Post
Table2–EvaluationofcementqualityineachGruen zone.
ZonesMean thickness (mm)
Radioluscence (%)
Bone resorption(%)
Bubbles(%)
1 9.1(0–30) 25.5 26.7 22 2 4.7(0–10) 60.4 1.1 37.2
3 4.9(1–13) 50 0 44.1
4 15.5(0–74) 32.5 0 33.7 5 4.8(2–10) 39.5 0 12.7 6 5.4(0–12) 55.8 0 15.1 7 6.3(0–15) 51.1 11.6 5.8 8 6.9(0–23) 23.2 12.7 10.4
9 3.5(0–10) 43 0 36
10 5.8(1–10) 58.1 0 36 11 15.6(0–73) 29 0 32.5 12 5.0(2–10) 45.3 0 27.9 13 6.6(2–11) 44.1 1.1 11.6 14 7.5(1–15) 18.6 13.9 1.1
(2.32%).Moreover,signsofdecreasedbonedensitywerealso foundinzones7and8.Bubbleswereobservedmorefrequently inzone3(38cases;44.19%)andinzone14(onecase).Nocase ofcementand/orstemfracturewasobserved(Table2).
An improvement in the assessment of cement mantle quality was made by calculating its proportion in relation to the cortical and stem thicknesses in the central zones inthe anteroposterior(zones 2and 6) andlateral (zones 9 and 13) views. Themean corticaland cement thicknesses inzone2were5.88mmand4.73mm, respectively;inzone 6,these valueswere 6.23mmand 5.34mm, respectively. A meanstemthicknessof13.6mmwasobservedinthefrontal view.Inthelateralradiographs,themeancorticalandcement thicknesses in zone 9 were 4.41mm and 3.43mm respec-tively, while in zone 13 these values were 5.31mm and 6.70mmrespectively.Inthesameview,themeanstem thick-nesswas 9.93mm. Thus, when considering the sequential measurementsbetweencortex–cement–stem–cement–cortex thickness,theproportionof1.2:1:2.8:1.1:1.3wasrecordedfrom lateraltomedialintheanteroposteriorview;theproportion of1.2:1:2.8:1.9:1.5wasrecordedfromanteriortoposteriorin thelateralview(Table3).
Intheassessmentofstemalignmentinthecoronalplane, varuspositioningwasobservedineight(9.3%)cases,witha meanvalueof3.5◦(2–8◦);valguspositioningwasobservedin
25(29%),withameanof2.5◦(1–8◦).Inthesagittalplane,
ante-curvatumwasobservedintwo(5%)cases,withameanvalue of3.5◦ (2–5),whilerecurvatumwasobservedin55(63.95%)
cases,withameanof4.2◦ (1–10◦).Inallcases,somedegree
ofdistaldisplacementofthestem(subsidence)wasobserved; themeandisplacementwas0.8mm(0–5mm).
Discussion
Fivedecadesafteritwasfirstpostulatedin1962,Charnley’s original conceptofaconical, polished andcemented shaft stillrepresentsthegoldstandard.16Theproblemofproximal
bonelossobservedfromthe1960sto1990srequiredchanges in the stem shape.17 Double-wedge femoral stem designs,
suchastheExeter(StrykerHowmedicaOrthopedics,Mahwah, New Jersey) and the CPT (ZimmerLtd., Swindon, England) present craniocaudalandanteroposteriortapering. Intriple wedgeimplants,athirdtaperisaddedinthelateraltomedial direction,aimingtoincreasetheloadontheproximalfemur, especiallyonthecalcar,whichdecreasesboneresorption.18
Bucklandetal.19madeaninterestingobservation,inwhich
afteraninitialreductionofbonemassinthecalcarregion, physicallyactivepatientspresentedanincreaseinbone den-sityinthisregionduringthefirsttwoyears.Purbachetal.16
showedabonestockimprovementin78.2%ofthepatientsin themedialregionina13-yearfollow-up.Inthepresentstudy,a decreaseinproximalmetaphysealbonedensityinthefemur wasobservedinzones1and 7(26.74%and11.63%, respec-tively).Therefore,therewasgreaterpreservationofthestock inthecalcarregion,afactorconsideredimportantbecauseit isanareasubjectedtogreateraxialload(Fig.3A).
Charnley and Kettlewell20 had calculated the relative
movement between the stem and themantle when repor-ting the function of the implant in a closed system on acryliccementintheirmonograph:“Despitethelackof adhe-sionbetweenthepolishedsurfaceoftheprosthesisandthe cement,thetaperedshapeoftheprosthesisisverysuitable forweighttransmission,asitwillbecometighterunderload (backtranslation).”21 When comparingfemoraltriple wedge
and double wedge components, no differences in clinical scores,complications,orsubsidencewereobserved.22
Sund-bergetal.,23whenassessingC-Stemstemmovementpatterns
in33THAswithatwo-yearfollow-up,observedamean dis-talmigrationof1.35mminallfemoralcomponents;mostof this movement occurred in thefirst three months.Eugene et al.,22 ina comparative analysis with a five-year
follow-upbetweendoublewedgeandtriplewedgestems,observed ameansubsidenceof0.82mmand0.77mmrespectively.In the present study, the levels of distal migration ofthe C-StemwerelowerthanthoseobservedbySundbergetal.23and
higher thanthe studybyEugeneetal.,22 withamean
dis-talmigrationof0.8mm.Therefore,nosignificantdifferences
Table3–Proportionbetweencortex,cement,andstemthicknesses.
Front Corticalzone2(mm) Cementzone2(mm) Stem(mm) Cementzone6(mm) Corticalzone6(mm)
Mean 4.73 5.34 5.88 6.23 13.6
Standarddeviation 1.92 1.79 1.69 1.79 1.93
Proportion 1.2 1 2.8 1.1 1.3
Profile Corticalzone9(mm) Cementzone9(mm) Stem(mm) Cementzone13(mm) Corticalzone13(mm)
Mean 3.43 6.7 4.41 5.31 9.93
Standarddeviation 1.66 1.87 1.39 1.8 2.87
zone1
A
B
C
zone7
1
2
3
7
6
5
Anterior
Posterior
4
Fig.3–Decreasedbonedensityinzone1andpreservationinzone7/calcar(A).Presenceofradiolucencyinzones2,3,4,and 5,andpresenceofbubblesinzones4,5,and6(B).Lateralviewradiographdisclosingtherecurvatumstempositioning(C).
wereobservedregardingsubsidence,i.e.,thisparameterwas withinthe mean displacement presentedin the literature. Excessivesubsidenceisanindirectindicatorofearlyimplant loosening,becauseitmayberelatedtothemovementofthe cementmantlerelativetothebone.24
Theclassificationofcementmantlequalityinthe imme-diatepostoperativeperiodproposedbyBarracketal.15in1992
isimportanttoassesstheeffectofthebestfemoral cemen-tationmethodsontheriskofincreaseinlooseningratesor earlierfailure.Inthepresentstudy,thisclassificationwasused toassessradiographs immediatelyaftersurgery.Five cases (5.81%)oftypeA,46(53.49%)oftypeB,27(31.4%)oftypeC, andeight(9.30%)oftypeDwereobserved.
Ek and Choong22 radiographically classified 192cement
mantlesonC-Stemfemoralcomponentsandalsoobserved ahigherfrequencyoftypeB(46.3%),followedbytypeAin 45.7%,andCin8%.Inthesamestudy,whencomparingthe qualityofthecementationwiththeExeterstemin189 radio-graphs,thoseauthorsobservedthattypeBwasalsothemost prevalentin56.6%,followedbytypeAin36.5%andtypeCin 6.9%.WhencomparingtheBerstocketal.25evaluationin2014
withthepresentstudy,ahigherprevalenceoftypeA(60%)was observed;38%presentedtypeB,2%presentedtypeC,and6.9% presentedtypeD.
Sundbergetal.23alsoreportedahigherfrequencyoftype
A(84.8%);typeBwasobservedin15.15%oftheirsample.An importantfactortoconsideristhatintheselasttwostudies, theoperativetechnique usedthird-generationcementation withpulselavage,whichwasnotperformedinthepresent study.Ahigher frequencyofradiolucency wasobserved in zones2(60.47%)and10(58.14%),followedbyzones6(55.81%) and7(51.16%),whilezones1,8,and14hadthelowest preva-lence,with25.58%,23.26%,and18.60%respectively(Fig.3B).
Comparing triple and double wedge stems, Ek and Choong22observeddivergentresults;radiolucentlineswere
morefrequentlyobservedinzone1whenusingC-Stem com-ponentsandinzones1and7whenusingExetercomponents. Thoseauthorsemphasizedthehypothesisthatradiolucency may arise earlydue tostem subsidenceand,therefore, do notnecessarilyindicateimplantloosening.Thistheorymay explainthepresenceofradiolucentlinesgreaterthan1mm
observedin32of33(96.9%)hipsevaluatedbySundbergetal.23
intheirstudy,Berstocketal.25alsoobservedahighfrequency
ofradiolucentlinesintheiranalysis,whichcorrespondedto 61%ofthehipsevaluated;radiolucencywasalsomore preva-lentinzones1(55%)and7(35%).
Inlateralviewimagesassessment,ahigherfrequencyof recurvatum wasobserved (meanof4.2◦) in55 hips,which
correspondedto63.95%ofthecases,whereasantecurvatum was observedintwohips(5%), withmeanof3.5◦ (Fig.3C).
In theanalysisofanteroposteriorradiographs, valgus posi-tioning was more frequent(25 cases[29%], mean of 2.5◦).
Varus positioningwasobservedineighthips(9.3%),witha mean of3.5◦. Thepresent authors believe thatthese
devi-ations canbeexplainedbytheprocess ofprogressivestem migration relative to the initial axis, as demonstrated by Sundbergetal.23Theseauthorsobserveddisplacementsthat
occurredmorefrequentlyinthemeanperiodofthreemonths postoperatively;intheanteroposteriorradiographs,theyalso observedvalgusmisalignmentinmostcases,witha preva-lence of 63.3%, while 15.1% of the hips presented varus positioning.
In their comparative evaluation between triple- and double-wedgestems,EkandChoong22observedlowerindices
ofstemdeviation.IntheC-Stemcomponents,theseauthors observedgreatermisalignmentinvarus,withafrequencyof 3.7%,comparedwith2.5%ofvalguspositioning.IntheExeter stems,varuspositioningwasrecordedin5.9%ofcases,vs.no casesofvalgus.Itshouldbenotedthatthislowerfrequency ofmisalignmentsisduetothefactthatthoseauthorsonly considereddeviationsanglesgreaterthan5◦.
recurvatumofthe femoralstem.Nostudiescalculatingthe ratiobetween cortical,cement mantle,and stemthickness wereretrievedintheliterature.
Conclusion
TheC-Stemtriplewedgecementedfemoralstempresented satisfactoryresultsregardingcementationpatternand qual-ity, implant placement,secondary accommodation pattern, andthepresenceofosteolysisandstressshielding,bothin relation to literature data regarding double wedge models andtodata onthissame implant byotherauthors.Itwas proven to be a safe, predictable, and reliable cementation method.
Conflicts
of
interest
Theauthorsdeclarenoconflictsofinterest.
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