Rev. bras. ortop. vol.51 número3

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SOCIEDADE BRASILEIRA DE ORTOPEDIA E TRAUMATOLOGIA

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

Original

Article

Initial

experience

of

use

of

an

articulated

external

fixator

in

treating

Legg-Calvé-Perthes

disease

by

means

of

arthrodiastasis

during

the

active

phase

of

the

disease

夽

Carlos

Augusto

Malheiros

Luzo,

Roberto

Guarniero

∗

_,

_Nei

_Botter

_Montenegro,

Rui

Maciel

de

Godoy

Junior

DepartmentofOrthopedicsandTraumatology,SchoolofMedicine,UniversidadedeSãoPaulo,SãoPaulo,SP,Brazil

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t

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o

Articlehistory: Received22April2015 Accepted25August2015 Availableonline4May2016

Keywords:

Legg-Calvé-Perthesdisease Orthopedicprocedures Externalfixators Hipjoint

a

b

s

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t

Objective:TopresentthepreliminaryresultsfromtreatingpatientswithLegg-Calvé-Perthes Disease(LCPD)bymeansofhiparthrodiastasisusingamonolateralexternalfixatorapplied tothehipandtosuccinctlydescribethesurgicaltechniqueused,inaprospectivestudy. Methods:Prospectivestudyon18patientswithLCPDwhounderwentsurgicaltreatmentby meansofthehiparthrodiastasistechniqueusingamonolateralexternalfixator.Therewere 13maleandfivefemalepatientsofmeanage8.5years,rangingfromfiveto13years.Allthe patientspresentedunilateralhipimpairment:nineontherightsideandnineontheleft. Theresultswereevaluatedatmaturityusingclinicalandradiologicalcriteria.

Results:Allthepatientsevolvedwithimprovementofjointmobility,andpainreliefwas achievedin88.9%ofthem.Reossificationofthefemoralepiphysisoccurredwithinthefirst threemonthsofthetreatment.Thehipsoperatedatthenecrosisstageofthediseasedid notpassedthroughthefragmentationstage,thusshorteningtheevolutionofthedisease. Theresultswere77.8%satisfactoryand22.2%unsatisfactory.

Conclusion: Hiparthrodiastasiswithamonolateralexternalfixatorduringtheactivephase of LCPDimprovedthe degree ofjointmobility. Useofthe arthrodiastasis techniqueat thenecrosisstageoratthefragmentationstage(activephaseofthedisease)presented satisfactoryresultsfromtreatmentofLCPD.

夽

StudyconductedattheDisciplineofPediatric,DepartmentofOrthopedyandTraumatology,FaculdadedeMedicina,Universidadede SãoPaulo,SãoPaulo,SP,Brazil.

∗ _{Corresponding}_author_.

E-mail:[email protected](R.Guarniero).

http://dx.doi.org/10.1016/j.rboe.2016.04.005

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Experiência

inicial

com

o

uso

de

fixador

externo

articulado

no

tratamento

da

doenc¸a

de

Legg-Calvé-Perthes

por

meio

de

artrodiástase

na

fase

ativa

da

moléstia

Palavras-chave:

Doenc¸adeLegg-Calve-Perthes Procedimentosortopédicos Fixadoresexternos Articulac¸ãodoquadril

r

e

s

u

m

o

Objetivo: Apresentaros resultados preliminaresdotratamento da DLCPcomousode artrodiástasecomfixadorexternomonolateralaplicadoaoquadriledescreversucintamente atécnicaoperatóriausadaemumestudoprospectivo.

Métodos: Estudoprospectivode18pacientescomDLCPsubmetidosaotratamento oper-atóriocomatécnicadeartrodiástasedoquadrilpormeiodefixadorexternounilateral.São 13pacientesdogêneromasculinoecincodofemininocomidademédiade8,5anoscom variac¸ãodecincoa13anos.Todosospacientescomacometimentounilateraldoquadril, nove àdireitaenove àesquerda.Aavaliac¸ãodos resultadosfoi feitanamaturidade e consideroucritériosclínicoseradiográficos.

Resultados: Todosospacientesevoluíramcommelhoriadamobilidadearticularcomalívio da dor obtidoem 88,9% dos pacientes. A reossificação da epífisefemoral ocorreunos primeirostrêsmesesdotratamento.Osquadrisoperadosnafasedenecrosenãopassaram pelafasedefragmentaçãoeabreviaramotempodeevoluçãodadoença.Osresultadosforam 77,8%satisfatóriose22,2%insatisfatórios.

Conclusões: Aartrodiástasedoquadrilcomfixadorexternomonolateralnafaseativada DLCPmelhoraograudemobilidadearticular.Oempregodatécnicadeartrodiástasenas fasesdenecroseefragmentac¸ão(faseativadadoenc¸a)apresentaresultadossatisfatórios notratamentodaDLCP.

Introduction

A childhoodhip disorder was described simultaneously in 1910byLegg(UnitedStates),Calvé(France),andPerthes (Ger-many)asanobscurealteration,pseudocoxalgia,andjuvenile deforming arthritis, which characterize the picture known todayasLegg-Calve-Perthesdisease(LCPD).1

Thediseaseisself-limiting,originatedbyischemiaofthe femoral head in varying grades, leading to bone necrosis. Theetiology isstillunknown, althoughseveralhypotheses thatattempttoexplainthedeficiencyinbloodsupplyofthe femoralheadhavebeenraised.2

TherearevariousdegreesofavascularnecrosisinLCPD, whichdependmainlyontheextentoftheinjury.Thepresence ofnewepisodesofischemia,likelytooccurduringthecourse ofthe disease,may resultinafemoralhead withdifferent stagesofself-repair.3

Initially,necrosisaffectstheepiphysealtissueandgiverise tonewlyformedbonetissue.Thehyalinecartilagebecomes relativelythickened,asitcontinuestoreceivenormal nutri-tionfromthesynovialfluidandmaintainsthesphericalshape ofthefemoralhead.4

In the second stage of the disease,there is fragmenta-tion ofthe femoralhead, followed byresorption and bone replacement, which lasts from one to three years. In this stage, there is a spread of necrotic tissue by vascularized connectivetissue;resorptionandnecrosiswhenreplacement by immaturebone tissue takes place. The epiphysis loses

height due tothe collapseof the trabecular boneand the absorptionoffragmentedbone.Inmoderateandseverecases, metaphysealchangesinthefemoralnecktakeplace.

Thethirdstageofthedisease,therepairingstage,is charac-terizedbythereplacementofnecroticandimmatureboneby maturebonetissue.Thehistopathologicalpatternobserved in this stageranges from areas without boneinfarctionto femoralheadswithseveralareasofnecroticandmaturebone. ThechildwithLCPDfeelspaininthehipand/orkneeand decreasedjointrangeofmotion,primarilyintheinternal rota-tionandhipabductionmovements.

Radiographic examination in LCPD is characterized by threesigns:firstistheshrinkingoftheossificationnucleusof thefemoralhead,withwideningofthejointspace;secondisa subchondralfracture(Caffey’ssign),which,accordingtoSalter and Thompson,3 _marks_the_beginning_of_the_clinical symp-tomsandisconsidered,dependingonitslength,aprognostic factorfordisease;thirdsignistheincreaseoftheradiopacity ofthefemoralhead,characterizingavascularnecrosis.From thatmomenton,therepairprocessproducesheterogeneous images,dependingontheareasofrevascularizationandnew necrosisoutbreaks.

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Treatmentresultsare influenced bymany factors;main onesareageatonset,maintenanceofthejointmobility,and degreeofhipinvolvement.

Thelong-termfollow-upofpatientstreatedinthis hospi-tal–withabductiondevices,femoralandiliacosteotomies, or cheilectomy – has indicated a tendency toward remod-eling, with alterations in the sphericity of the femoral head.5–7

ThetreatmentofLCPDhasasitsbasicprinciplethe pro-tection of the proximal femoral epiphysis. The idea of a treatmentmethodthatallowscenteringofthefemoralhead and providesprotectionagainst mechanicalbody load and against the action of pelvitrochanteric muscles is attrac-tive.

Inthisarticle,theauthorspresentthepreliminaryresults ofLCPDtreatmentwiththeuseofunilateralexternalfixator througharthrodiastasis, aimingtocreatenegativepressure onthe femoralhead and preserving thejoint space, in an attempttodecreasetheharmfuleffectsofsubchondral frac-turesanddestructionofthetrabecularboneofthefemoral head.

Material

and

methods

Thisprospectivestudyreportstheinitialexperiencewith18 patientswithLCPDsubmittedtosurgerywiththehip arthro-diastasistechniquethroughtheuseofaunilateralexternal fixator.

ThisstudywasapprovedbytheScientificCommitteeand ResearchEthicsCommitteeofourinstitution(DocumentNo. 201/95).

Thirteenmalesandfivefemales,withameanof8.5years ofage(range:5–13years),wereincluded.

Allpatientshadunilateralhipinvolvement:nineattheleft andnineattherightside.

Patientswereclassifiedaccordingtotheradiographic crite-riadevelopedbyCatterall8_and_by_Herring_et_al.9

Results were assessed considering clinical and radio-graphiccriteria.Asclinicalcriteria,theresponseofpatients inrelationtopaincontrolinthehipjointoftheaffectedside wereassessed,aswellasjointrangeofmotionandgeneral degreeofmovementofthehip:externalandinternalrotation, abductionandadduction,flexionandextension.

RadiographicevaluationincludedtheinitialCatterall8_and Herringetal.9_{classification,}_as_well_as_the_{classification}_for_the finalresultsproposedbyStulbergetal.10_at_skeletal_maturity_of thehipregion.Thecenter-edge(CE)angleoftheacetabulum wasalsomeasured.Thesphericityofthefemoralheadwas assessedaccording totheMose11 _method,_and_the _indexes andepiphyseal quotientwere measured.Theextentofhip subluxationwasalsoassessed.

ThesystemproposedbythePediatricOrthopaedicSociety ofNorthAmerica(POSNA),12_shown_in_Table₁_,_was_used_for theevaluationofpostoperativeresultsofpatients.

Inclusioncriteria

Patientsofbothgenders,withthediagnostic ofLCPD,with unilateralhip diseasepresentingrestrictionofthe affected

Table1–PediatricOrthopaedicSocietyofNorth-America (POSNA)assessmentsystem.12

Result Center-edgeangle Mosecircles

Good >20◦ ₀

Fair 15–19◦ ₂

Poor <15◦ _>2

joint movements, and pain duringactivities ofdailyliving wereincluded. TypesIII_orIV_in_the_Catterall8_{classification}

andwithtwoormore“radiographicrisksigns”;typesBorCin theclassificationbyHerringetal.9_;_patients_in_the_early_stages ofradiographiccondition,i.e.,condensationorfragmentation, which characterizes the “active” stage ofthe disease were included.

Exclusioncriteria

Patients with bilateral involvementof the hips and whose radiographicexaminationpresentedinitialsubluxationabove 50%ofthefemoralheadcircumferencemeasuredbythe Dick-ensandMenelaus13_method,_as_well_as_patients_in_the_stage offemoralheadremodelingaccordingtoradiographic analy-sis.

Statisticalanalysis

Descriptive statistics of quantitativeordinal parameters of age,timeofusageoftheexternalfixator,follow-uptime,and rangeofmotion(externalandinternalrotation,abductionand adduction,flexionandextension)werecalculated:mean(M), standard deviation(SD), standarderror ofthe mean (SEM), maximum(Max)andminimumvalues(Min),andthenumber of cases (N). In the comparison of two groups of depend-ent paired ordinal parameters, the paired t-test was used, in caseofparametric distributions, and the Wilcoxon test, incaseofnon-parametric distributions.Mann–Whitney’sU testwasusedforindependentnon-parametricsamples. Abso-lute and relative frequencydistribution (%) was calculated to describe normaldistributions (qualitative).Comparisons betweennominaldistributionsweremadeusingFisher’sexact test.

Thesignificancelevelof5%(˛=0.05)wasadopted. Signifi-cantresults(differences)werehighlightedbyasterisks.

Surgicaltechnique

Indications for surgical treatment with hip arthrodiastasis throughexternalfixationinLCPDwereasfollows:

1) Pain,eveninthelowestdegree;

2) Decreaseinthedegreeofmobilityoftheaffectedjoint; 3) CatterallgroupsIII_orIV_;

4) Atleasttworadiographicsignsof“headatrisk”; 5) Lessthan50%subluxationofthefemoralhead.

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Fig.1–Illustrationofthepositionoftheexternalfixator. TwotothreeSchanzscrewsposteriorlyandinferiorly. (Impolfix®_,_Impol,_São_Paulo,_Brazil).

Source:DepartmentofOrthopedicsandTraumatology,

FMUSP.

Aunilateral,articulatedexternalfixator(Impolfix®_,_Impol,_São Paulo,Brazil)wasused.Theexternalfixatorisappliedwitha coupleofSchanzscrewspositionedintheacetabularregion andanothercoupleofSchanzscrewsinthediaphysealzone ofthefemur.

Jointdiastasisisappliedduringsurgeryaimingtocorrect Shenton’slineunderfluoroscopiccontrol.

Figs.1–4illustratethemainstepsforpositioningthe uni-lateralexternalfixator.

Fig.2–Illustrationofthepositionoftheexternalfixator fromtherotationcenterofthefemoralhead(arrow). (Impolfix®_,_Impol,_São_Paulo,_Brazil).

Source_:_Department_of_Orthopedics_and_{Traumatology,}

FMUSP.

Fig.3–Illustrationofthepositionoftheexternalfixator (Impolfix®_,_Impol,_São_Paulo,_Brazil)_and_how

arthrodiastasisisperformed.

Source_:_Department_of_Orthopedics_and_{Traumatology,}

FMUSP.

Postoperative

Ifhipdiastasisisnotachievedthroughsurgery,itcanbeslowly progressedduringpostoperativeperiodof10–15days.Weekly dressings are usedinthe areasofcutaneousemergenceof theSchanzscrews.ControlX-raysareperformedatfour-week intervals.Theexternalfixatorremainsinsertedfor approxi-matelythreemonths.

Results

Clinicalanalysis

Theassessmentofage,sex(maleandfemale),andtheaffected side(rightorleft)ofthepatientsisshowninTable2.Table3

presents thepre- andpostoperativeclinical analysisofthe degreeofhipamplitude.

Radiographicanalysis

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Fig.4–Photographoftheidealpositioningofmonolateralexternalfixator(Impolfix®_,_Impol,_São_Paulo,_Brazil). Source_:_Department_of_Orthopedics_and_{Traumatology,}_FMUSP.

Tables5–7 present the studies comparingthe outcomes aftersurgeryforPOSNAcriteriaandthefollowingfactors:sex, age,andfinalresult.

Figs.5–8showtheevolutionofapatientoperatedat7years and4monthsandtheprogresstwoyearsaftersurgery.

Table2–Presentationofpatientsaccordingtoage (years),sex,andaffectedside.

Order Age(years) Sex Side

1 8 M R

2 12 M L

3 9 M L

4 9 F L

5 9 M L

6 13 M R

7 6 F R

8 9 M R

9 8 M L

10 10 M L

11 7 M R

12 8 M L

13 9 M L

14 10 M R

15 7 F R

16 9 F R

17 5 F R

18 5 M L

M,males(13);F,females(5);R,right(9);L,left(9). Age–meanof8.5years;<7years=16.7%;>7years=83.3%.

Discussion

LCPDisaself-limitingconditioncausedbyischemiaand vary-ingdegreesoffemoralheadnecrosis.Thecauseofischemia iscurrentlyunknown;many hypothesesaresuggested,but thereisstillnocompleteproof.Currently,themostaccepted theoriesaredelayinskeletaldevelopment,microtrauma,and vascularalterations.14

According toBensahel,15 _the _highest_frequency_of_LCPD isobservedintherangeof4–8years;itisanrarediagnosis outsidetheagerangeof2–10years.Inthepresentstudy,the meanageatdiseaseonsetwas8.5years,rangingfrom5to 13.Thisgroupofpatientscanbeconsideredapoorprognostic riskgroup,asageatdiseaseonsetisoneofthefactorsthat mostinfluenceoutcomes.16–18

ThepresentstudyincludedpatientsclassifiedasCatterall typesIII_andIV_,_which_are_the_two_groups_with_worst prog-nosis. Furthermore, patients had atleast two radiographic signsof“headatrisk.”Consideringthelimitationof(mean) movementamplitudeoftheaffectedhip,theneedfor surgi-caltreatmentindicationforthegroupofpatientsstudiedwas proven.

InthesurgicaltreatmentofLCPD,varizationosteotomies of the femur or the iliac bone (acetabulum) are the sur-gical treatment modalities most used to achieve femoral head containment. The literature review retrieved studies thatshowednosignificantdifferencebetweenbothtypesof osteotomy.19,20

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Table3–Degreeofrangeofmotionofthehip,pre-andpostoperative,withstatisticalanalysis.

Amplitude(◦₎ _Preoperative _{Postoperative} _Comparison

Abduction 20.6±11.49(2.71) 40.3±9.1(2.1) WilcoxonTc=34

To=0

Adduction 16.9±5.18(1.22) 20.8±4.62(1.09) WilcoxonTc=2

To=0

Flexion 92.2±0.17(0.04) 115.5±11.99(2.83) tPAIRED

t=4.73p=0.0002 Extension 16.4±2.87(0.68) 19.2±2.57(0.61) tPAIRED

t=4.61p=0.0002 Externalrotation 16.9±11.65(2.75) 37.5±11.41(2.69) WilcoxonTc=40

To=1

Internalrotation 9.3±9.54(2.25) 25.6±12.23(2.88) WilcoxonTc=29

To=1

Tc,criticalT;To,Tobtained.

Fig.5–Malepatient,7yearsand4months,CatterallIII.Preoperativeimage.

Fig.6–PatientfromFig.1,atoneandtwomonthspostoperatively.Newlygrowingtissue(arrow).

Table4–LCPDstagingandfrequencydistributionofthe resultsaccordingtotheCatterallandHerring

classifications.

Classification Catterall Herring

III–7(38.9%) A–1(5.6%) IV–11(61.1%) B–12(66.7%)

C–5(27.8%)

Total 18(100%) 18(100%)

by Volkov and Oganesian.21 _The _use _of_an_external _fixator to promotethe maintenanceofthe joint space,utilized in variousjoints suchasknee,elbow,hip,andankle, hasalso been described for various orthopedic conditions, such as traumaandsequelae,septicarthritis,tuberculosis, epiphys-iolysis,chondrolysis,andLCDP.21–25_According_to_van_Valburg etal.,26_the_maintenance_of_the_joint_space_provided_by_the externalfixator,evenafterashortperiodoftreatment, indi-cates some joint repair, an important factor for obtaining clinicalimprovementofthepatient.

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Table5–Frequencydistributionofthepostoperative resultsinthePOSNAclassificationofaccordingtosex. ComparisonbyFisher’sexacttest(˛=0.05).

POSNA

Sex Satisfactory Unsatisfactory Total

Male 11(61.1%) 2(11.1%) 13(72.2%) Female 3(17.7%) 2(11.2%) 5(27.8%)

Total 14(77.8%) 4(22.2%) 18(100%)

Fisherp=0.30.

Table6–Frequencydistributionofthepostoperative resultsinthePOSNAclassificationofaccordingtoage range.ComparisonbyFisher’sexacttest(˛=0.05).

POSNA

Agerange(years) Satisfactory Unsatisfactory Total

<7 2(11.1%) 1(5.5%) 3(16.7%) ≥7 12(66.7%) 3(16.7%) 15(83.3%)

Total 18(100%) 4(22.2%) 18(100%)

Fisherp=0.30.

Table7–Frequencydistributionofthepostoperative resultsinthePOSNAclassification.

POSNArating Absolute Relative(%)

Satisfactory 14 77.8

Unsatisfactory 4 22.2

Total 18 100.0

treatment.Theischemic femoralheadissubjectedto pres-sure overloadevenwhenthe patient isatrest,due tothe actionofthe muscles.Theideaofachievingneutralization ofthemusclestrengthandoftheweightforceactingonthe

Fig.7–PatientfromFig.1,atthreemonthspostoperatively. Reossificationofthefemoralhead.

femoralhead,whichincreasesthejointspace,creatinga situa-tioninwhichthearticularcartilagecanregenerateafterinjury, is veryattractive. Adding movement tothe methodallows foranimprovementinsynovialfluidcirculationand conse-quentimprovementofarticularcartilagenutrition,givingthe methodveryusefulmechanicalandbiologicalcharacteristics forthetreatmentofLCPD.Moreover,thistechniquepreserves thearticularsurfaceandprotectstheepiphysisfromforces actingonthehip;italsoreducestheriskofflatteningofthe headandcollapseofthenewlyformedvessels.Accordingto Stulberg,10_decreased_joint_space_is_the_factor_that_shows_the greatestassociationwithclinicallong-termresultsinLCPD.

DuringthenaturalcourseofLCPD,thehipundergoesthe phasesofsynovitis,necrosis,andremodeling4_; arthrodiasta-siswasusedonhipsinthenecrosisorfragmentationstages (“active” stages of the disease). Afast revascularization of thefemoralepiphysiswasobservedinanintervalofoneto threemonths(Figs.5–8).Whenhipsweretreatedinthe necro-sis stage,regenerationoccurred without the fragmentation

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phase.Thisphenomenonisconsistentwiththatdescribedby Volponetal.27

AllmodalitiesoftreatmentforLCPDarebasedin mechan-ical concepts. Arthrodiastasis offers a biological concept beyondthemechanicalconceptofanatomicaljoint centraliza-tionandmechanicalloadprotectionimposedonthejoint.28–30 AccordingtotheconceptsofIlizarov,31_{arthrodiastasis}_induces angiogenesisaroundtheentirejoint.Itisimportanttonote that,undertheinfluenceofmechanicaltraction-loadoffered byarthrodiastasis,activehistogenesisoccursnotonlyinthe bone,butalsointheregionalsofttissues;yet,accordingto Ilizarov,theprocessoftissueformationandgrowthinanadult organismhasmanyfeaturesincommonwithtissue forma-tionduringtheembryonicandimmediatepostnatalperiods.

Figs.6and7presentanexampleofthistypeoftissue forma-tion.

The preliminary satisfactory results of treatment with arthrodiastasisobtainedin77.8%ofpatientscanbe consid-eredasoverall“good,”thusaccreditingthetechniqueasan effectiveLCPDtreatmentmethod.

TheauthorsagreewithKucukkayaetal.32 _that arthrodi-astasisisagoodoperativetreatmenttechniqueforpatients agedabove6yearsandconsideredashavingpoorprognosis inthecriteriasetforthbyCatterall.Moreover,theprocessof reossification/remodelingofthefemoralheadappearstobe shortenedbyarthrodiastasisoftheaffectedhip.

Conclusion

Hip arthrodiastasis with unilateral external fixator in the activestagesofLCPDimprovesthedegreeofjointmobility.

Theuseofthearthrodiastasistechniqueinthenecrosisand fragmentationstages(activestagesofthedisease)presents satisfactoryresultsinthetreatmentofLCPD.

Conflicts

of

interest

Theauthorsdeclarenoconflictsofinterest.

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