w w w . r b o . o r g . b r
Original
Article
Analysis
on
the
risk
of
contralateral
proximal
femoral
epiphyseal
slippage
using
the
modified
Oxford
score
夽
Jamil
Faissal
Soni
∗,
Weverley
Rubele
Valenza
∗,
Wellington
Keity
Ueda,
Gisele
Cristine
Schelle,
Anna
Carolina
Pavelec
Costa,
Fernando
Ferraz
Faria
HospitalUniversitárioCajuru,PontifíciaUniversidadeCatólicadoParaná(PUC-PR),Curitiba,PR,Brazil
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Articlehistory:
Received20July2014 Accepted1September2014 Availableonline9September2015
Keywords:
Dislocatedepiphysis/pathology Dislocatedepiphysis/surgery Dislocatedepiphysis/radiography
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Objective:TodeterminetheapplicationofthemodifiedOxfordscoreamongpatientswith proximalfemoralepiphysealslippage(PFES)asanaidtoindicatingprophylacticsurgical treatmentonthecontralateralhip.
Methods:Retrospectiveanalysisonthemedicalfilesofpatientsattendedattheinstitution wheretheauthorswork.Fromthese,patientsattendedbetween2008and2011who pre-sentedunilateralPFESandwerefollowedupforaminimumoftwoyearswereselected. Patientswereexcludediftheypresentedendocrinedisease,metabolicdisease,Down syn-dromeorradiographsthatwereinadequatefordeterminingthemodifiedOxfordscore. Theinitialradiographsreceivedscoresrangingfrom16to26.Statisticalanalysiswasused todeterminewhetherthescoringwaspredictiveoffuturedevelopmentofcontralateral slippage.
Results:Amongthe15patientswithunilateralPFESthatwereselected,five(33.3%)evolved withcontralateralslippage.Thepatientsweredividedintotwogroups.Fourpatientswere consideredtopresentriskandthreeofthemdevelopedcontralateralslippage.Inthegroup thatwasconsiderednottopresentrisk,therewere11patientsandtwooftheseevolved withcontralateralslippage.Thus,therewasatendencyforthepatientsinthegroupthat developedthediseasetodifferfromthegroupthatdidnotdevelopit,inrelationtotherisk classification.
Conclusion:AlthoughapplicationofthemodifiedOxfordscorewasnotstatistically signifi-cantinoursample,wenotedatendencytowardcontralateralslippageamonghipswithlow scores.
©2014SociedadeBrasileiradeOrtopediaeTraumatologia.PublishedbyElsevierEditora Ltda.Allrightsreserved.
夽
WorkperformedinthePediatricOrthopedicsGroup,HospitalUniversitárioCajuru,Curitiba,PR,Brazil.
∗ Correspondingauthors.
E-mails:[email protected](J.F.Soni),[email protected](W.R.Valenza).
http://dx.doi.org/10.1016/j.rboe.2015.08.016
Análise
do
risco
do
escorregamento
epifisário
femoral
proximal
contralateral
pelo
escore
de
Oxford
modificado
Palavras-chave:
Epifisedeslocada/patologia Epifisedeslocada/cirurgia Epifisedeslocada/radiografia
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e
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o
Objetivo: Determinara aplicac¸ão do escore de Oxford modificado em pacientes com escorregamentoepifisáriofemoralproximal(EEFP)noauxíliodaindicac¸ãodotratamento cirúrgicoprofiláticodosquadriscontralaterais.
Métodos: Análiseretrospectivadosprontuáriosdospacientesatendidosnainstituic¸ãona qualosautorestrabalham.Foramselecionadosaquelescomumtempodeseguimento mín-imodedoisanos,atendidosde2008até2011,queapresentaramEEPFunilateral.Oscritérios deexclusãoforampacientescomdoenc¸aendócrinaoumetabólica,síndromedeDowne aquelescomradiografiasinadequadasparadeterminarapontuac¸ãonoescoredeOxford modificado.Asradiografiasiniciaisreceberamumapontuac¸ãoquevariade16a26.Aanálise estatísticafoiusadaparadeterminarseapontuac¸ãofoipreditivadodesenvolvimentofuturo dedeslizamentocontralateral.
Resultados: Dos15pacientesselecionadoscomEEFPunilateral,cinco(33,3%) evoluíram paraoescorregamentocontralateral.Ospacientesforamdivididosemdoisgrupos, qua-tropacientesforamconsideradosderiscoedessestrêsdesenvolveramoescorregamento contralateral.Nogruposemriscohavia11pacientes,doisevoluíramparaoescorregamento contralateral.Nota-seassimumatendênciadequepacientesdogrupoquedesenvolveua doenc¸adifiramdogrupoquenãodesenvolveuemrelac¸ãoàclassificac¸ãoderisco.
Conclusão: Apesardenanossaamostraaaplicac¸ãodoescoredeOxfordmodificadonão tersidoestatisticamentesignificativa,notamosumatendênciaparaoescorregamento con-tralateralnosquadriscomescorebaixo.
©2014SociedadeBrasileiradeOrtopediaeTraumatologia.PublicadoporElsevier EditoraLtda.Todososdireitosreservados.
Introduction
Proximalfemoralepiphysealslippageisadiseasethatmainly affectsthehypertrophiczoneofthegrowthplatecartilage.It affectstheprepubescentandpubescentpopulationatan inci-denceof0.2–10inevery100,000adolescents.Itoccursmore frequentlyinboysanditscommonestclinicalmanifestation ispainintheinguinalregionand/orknee,associatedwith lim-itationoftheflexionandinternalrotationmovementsofthe hip.1,2
Involvement of the contralateral side (bilaterality) is observedin20–40%ofthepatients,andin90%ofthecases, furtherslippageoccurswithin12–18monthsaftertheinitial manifestation.3,4
The true etiology of this illness remains unknown, althoughgeographical, racial and seasonalepidemiological data suggest that environmental and genetic factors may influenceitsdevelopment.2,5 Importantcharacteristicssuch
asanacceleratedgrowthspurt,obesityandhormonal disor-dershavebeenrecognizedasriskfactors.6–9
Therelativelyhighriskofdevelopingcontralateralslippage hasledmanyauthorstorecommendprophylacticfixationof thehip,eveniftherearenosymptoms,inanattemptto pre-serveitsanatomy.10
However, routine prophylactic fixation subjects a large numberofpatientstounnecessarysurgery,giventhat60–75% oftheindividualswhopresentunilateralslippagewillnever developthispathologicalconditioncontralaterally.11,12
More-over, prophylactic surgery may predispose toward certain
complications,suchas:infection,implantbreakage, avascu-larnecrosis,chondrolysisorsubtrochantericfracturingofthe femur.13,14
Theobjectiveofthepresentstudywastoretrospectively evaluatetheapplicabilityofthemodifiedOxfordscorefor pre-dictingoccurrencesofcontralateralslippageinpatientswith unilateralproximalfemoralepiphysealslippage.
Materials
and
methods
Thiswasanobservationalcross-sectionalretrospectivestudy inwhichthemedicalrecordsandradiographsofallpatients with adiagnosis ofunilateral proximal femoralepiphyseal slippage who were attended and treated by the pediatric orthopedicsgroupofourinstitutionbetweenJanuary2008and December2011werereviewed.Fromthisreview,31patients wereselectedand,amongthese,thosewhopresentedproven metabolicorendocrinedisease,Downsyndromeorbilateral proximalfemoralepiphysealslippageatthetimewhenthey were first seen,and those withfollow-ups shorterthan 24 months,wereexcluded.Inthismanner,15patientspresenting theinclusioncriteriaofunilateralproximalfemoral epiphy-sealslippageandatleasttwoyearsoffollow-upwerefinally selected.
All the radiographs were evaluated using the modified Oxford score as described byStasikelis et al.15 (Fig. 1 and
Table1–ModifiedOxfordscoreamongthepatients.
Sex Age Initialside Secondaryside I TC FE GT LT Total
1 M 10 L R 3 1 5 5 3 17
2 M 10 L R 3 1 5 5 4 18
3 M 11 L R 3 1 6 5 4 19
4 M 14 R L 3 1 6 6 4 20
5 F 11 L R 3 1 5 5 4 18
6 F 11 L 3 1 6 4 4 18
7 M 14 L 5 2 7 5 4 23
8 M 14 L 5 3 6 5 4 23
9 F 11 L 4 2 7 5 4 22
10 M 13 L 5 6 6 5 4 26
11 F 13 R 4 3 7 5 4 23
12 M 15 R 5 3 6 5 4 23
13 M 11 L 3 1 6 6 3 19
14 F 13 L 5 3 7 6 5 26
15 F 12 L 3 2 6 5 4 20
I,ilium;TC,triradiatecartilage;FE,femoralepiphysis;GT,greatertrochanter;LT,lessertrochanter.
epiphysis,greatertrochanterandlessertrochanter.Thetotal scoreisdeterminedfromsummingthescoresofeachitem, anditcanrangefrom16to26.
Thisstudywasapprovedbytheresearchethicscommittee underthenumber13090913.9.0000.0020.
Ilium
Triradiate cartilage
Head of femur
Greater trochanter
Lesser trochanter
3
Source: Popejoy D, Emara K, Birch J. Prediction of contralateral slipped capital femoral epiphysis using the
4 5
3 4 5
4 5 6
5 6 7
1 2 3
Fig.1–ModifiedOxfordscore.
Source:PopejoyD,EmaraK,BirchJ.Predictionof
contralateralslippedcapitalfemoralepiphysisusingthe modifiedOxfordboneagescore.JPediatrOrthop.
2012;32(3):290–4.
Results
Amongthe15patientswithunilateralproximalfemoral epi-physeal slippage who were initially selected, five (33.3%) evolved tocontralateral slippage. Ninepatients (60%) were maleandsix(40%)werefemale.Amongthefivewho devel-opedcontralateralproximalfemoralepiphysealslippage,four (80%)were maleandone(20%)wasfemale,whichwasnot statisticallysignificant.
ToanalyzetheresultsfromthemodifiedOxfordscoreas apredictivefactorforcontralateralproximalfemoral epiphy-sealslippage,wedividedthepatientsintotwogroups(with andwithoutrisk).Patientsatriskwereconsideredtobethose withtotalscoresof16,17or 18.Thiswasbecause Popejoy etal.16demonstratedthatforthesescores,thepositive
pre-dictive valuefor developingcontralateral proximalfemoral epiphysealslippagewas96%andthenegativepredictivevalue was92%(Table2).
Table2–Likelihoodthatproximalfemoralepiphyseal slippagemightdevelop,basedonthemodifiedOxford scoreandusingalinearregressionmodel.
ModifiedOxfordscore Likelihoodofcontralateral
proximalfemoralepiphyseal slippage(%)
16 100
17 97
18 85
19 44
20 5
21 1
22 1
23 0
24 0
25 0
26 0
Fourpatientswereinthegroupatriskandthreeofthem developedcontralateralslippage.Therewere 11patients in thegroupthatwasnotatrisk,andtwoofthemevolvedto contralateralslippage. From Fisher’s exact test, atendency forpatientswhodevelopedthediseasetodifferfromthose whodidnotdevelopitwasnotedinrelationtotheriskscore (p=0.077).
In the statistical analysis, the results obtained were described in terms ofmeans, minimumvalues, maximum valuesandstandarddeviations(quantitativevariables)orin termsoffrequenciesandpercentages(qualitativevariables). Toevaluatetheassociations betweenthedichotomous cat-egorical variables and the risk assessed using the Oxford score, Fisher’s exact text was used. To make comparisons betweenthe groups inrelation toage, the non-parametric Mann–Whitneytestwasused.pvalues<0.05indicated sta-tisticalsignificance.ThedatawereanalyzedusingtheSPSS v.20.0®computersoftware.
Discussion
Prophylactic surgical treatment for contralateral proximal femoral epiphyseal slippage at the time when slippage is first presented is a matter of controversy. Hägglund17
demonstratedthat theriskofarthrosisinthecontralateral hip could be reduced through prophylactic fixation. Thus, they suggested that all patients with unilateral proximal femoralepiphysealslippageshouldreceiveprophylactic treat-ment for the contralateral hip, given the high incidence of future contralateral slippage and the low complication rate.
Althoughthisprocedureisrelativelysimpleandhaslow morbidity,ithasinherentcomplications,likeanysurgical pro-cedure. Therefore, it is essential to evaluate the risks and benefits.Avarietyoffactors seemtohaveaninfluenceon thelikelihoodthatcontralateralproximalfemoralepiphyseal slippagemightdevelop.Theseincludethefollowing:sex,age, obesity, ethnicity and the contralateralgrowth plate angle. Although there is an association with etiology, these fac-torscannot beconsidered to bepredictors ofcontralateral slippage.18Theclassicalindicationsforthisprocedurerelate
toage(forboys,lessthan12.5years;andforgirls,lessthan 10.5years)and/orprovenconcomitantendocrinedisorders.19
Inourstudy,ameanageof10.5yearsforprophylacticfixation wasalsoobserved.
In this light, it becomes important toseek aneffective methodforensuringthatindicationsforprophylacticfixation ofahiparesaferandmorereliable.Becauseofthesimplicity andaccessibilityofthemodifiedOxfordscoreforassessing bonematurity,thismethodisbecomingevermorecommonly used.Theradiographsneededforapplyingit arethe same onesusedintheinitialevaluationandinfollowinguppatients withproximalfemoralepiphysealslippage.
Stasikelisetal.,15inastudyon50patients,wasthefirst
todemonstratethatthereisalineardistributionbetweenthe modifiedOxfordscoreandtheriskthatcontralateralproximal femoralepiphysealslippagemightdevelop.However,because oftheirsmallnumberofpatients,theclinicaldecisionfavoring prophylactictreatmentdidnothaveanyimpact.
Popejoy et al.16 evaluated 260 patients with proximal
femoralepiphysealslippageandfoundthat64subsequently developedcontralateralslippage.Byfollowingthesamemodel of linear distribution, theydemonstrated that the patients withmodifiedOxfordscoresof16,17or18hada96% probabil-ityofdevelopingcontralateralslippage.Inourstudy,outofthe five patientswho presentedcontralateralproximalfemoral epiphysealslippage,twowerenotinthegroupatrisk.
We had a total offive patients (33%)with contralateral proximalfemoralepiphysealslippage,whichcorroboratesthe current literature.Loder3 and Hurley etal.4 had previously
demonstratedvaluesclosetothisintheirstudy(20–40%). Inourstudy,theleftsidewasmoreaffected(80%).Inthe literaturetoo,theleftsideismoreaffected,inaratioof3:2,as demonstratedbyLoder3inamulticenterstudypublishedin
1996.
Conclusion
Inoursample,applicationofthemodifiedOxfordscoredid notshowstatisticalsignificance.However,wecouldinferthat therewasastrongtendencyforhipswithlowscorestoevolve towardcontralateralslippage.Thus,thisscoreisafurthertool thatmightaidinmakingthedecisiononwhethertouse pro-phylacticfixation.
Conflicts
of
interest
Theauthorsdeclarenoconflictsofinterest.
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