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REVIEW
ARTICLE
Complex
primary
total
hip
arthroplasty
S.
Boisgard
a,b,∗,
S.
Descamps
a,b,
B.
Bouillet
a,baServicedechirurgieorthopédiqueettraumatologique,hôpitalGabriel-Montpied,CHUdeClermont-Ferrand, 63003Clermont-Ferrand,France
bFacultédemédecine,universitéClermont-1,63001Clermont-Ferrand,France
Accepted:23November2012 KEYWORDS Totalhip arthroplasty; Softtissue; Neuromuscular conditions; Hipdysplasia; Hipfracture
Summary Althoughtotalhiparthroplastyisnowaclassicprocedurethatiswellcontrolledby orthopedicsurgeons,somecasesremaincomplex.Difficultiesmaybeduetoco-morbidities: obesity,skinproblems,muscularproblems,ahistoryofneurologicaldiseaseorassociated mor-phological bonedeformities. Obesepatients must beinformedof their specificrisks anda surgicalapproachmustbeusedthatobtainsmaximumexposure.Healingofincisionsisnota particularproblem,butadhesionsmustbeassessed.Neurologicaldiseasesmayrequire teno-tomyandtheuseofimplantsthatlimitinstability.Specifictechniquesorimplantsarenecessary torespecthipbiomechanics(offset,neck-shaftangle)incaseofalargeleverarmorcoxavara. Incaseofarthrodesis,beforeTHAcanbeperformed,theriskofinfectionmustbespecifically evaluatediftheetiologyisinfection,andthestrengthoftheglutealmusclesmustbe deter-mined.Congenitalhipdysplasiapresentsthreeproblems:thepositionandcoverageofthecup, placementofaspecificorcustommadefemoralstem,withanosteotomyifnecessary,andfinally loweringthefemoralheadintothecupbyfreeingthesofttissuesorashorteningosteotomy. Acetabulardysplasiashouldnotbeunderestimatedinthepresenceofsignificantbonedefect (BD),andreconstructionwithabonegraftcanbeproposed.Sequelaefromacetabular frac-turespresentsaproblemofassociatedBD.Internalfixationhardwareisrarelyanobstaclebut thesurgicalapproachshouldtakethisintoaccount.Treatmentofacetabularprotrusioshould restoreanormalcenterofrotation,andpreventrecurrentprogressiveprotrusion.Theuseof bonegraftsandreinforcementringsareindispensible.Femoraldeformitiesmaybecongenital orsecondarytotraumaorosteotomy.Theymustbeevaluatedtorestorehipbiomechanicsthat areasclosetonormalaspossible.Fixationofimplantsshouldrestoreanteversion,lengthand theleverarm.MostproblemsthatcanmakeTHAadifficultproceduremaybeanticipatedwith properunderstandingofthecaseandthoroughpreoperativeplanning.
©2013PublishedbyElsevierMassonSAS.
∗Correspondingauthor.Servicedechirurgieorthopédiqueet trau-matologique,hôpitalGabriel-Montpied,CHUdeClermont-Ferrand, 63003Clermont-Ferrand,France.
E-mailaddress:[email protected] (S.Boisgard).
Introduction
Totalhiparthroplastyisafrequentprocedurefor orthope-dicsurgeonsspecializedinthelowerextremities.Thereare morethan100,000hipreplacementsperyearandalthough
1877-0568/$–seefrontmatter©2013PublishedbyElsevierMassonSAS. http://dx.doi.org/10.1016/j.otsr.2012.11.008
failure.
Likeallsurgicalprocedures,THAalsoinvolvesmanaging risks.ThusadifficultTHAprocedureisaTHAthatincreases functional,infectious,andneurologicalrisksorthatinvolves technicaldifficulties,andtheformermaybelinkedtothe latter.
This is why THA requires planning: which surgical approachshouldbeusedforthesofttissues?Whichimplant? How should the implant be positioned in relation to the patient’s anatomy? This approach to planning, which was inspiredbyaviationproceduresandwhichtakestheformof achecklist in theoperatingroom,shouldlimitthe riskof unforeseenproblemsduringsurgeryaswellasoflong-and short-termcomplications.
Difficulties
associated
with
soft
tissue
anomalies
Thiselementmustbetakenintoaccountevenifitcannot beseenonimaging.
Limitingsofttissuetraumadoesnotonlymeanmakinga smallincision,butitalsomeans makingitlargeenoughto avoidhavingtostretchtheskin,preservingthemusclesand exposingthebonessothatreplacementcomponentscanbe correctlypositioned.
Theserequirementsmeanthatasurgicalapproachthat canbeextendedshouldbechosen.
Weight
Inobesepatientstheriskofthefollowingcomplicationsare significantly increased:postoperative mortality, infection, thromboemboliccomplicationsanddislocation[1,2].
THAinthesepatientsisdifficultfromtheoutsetduring thepreoperativeconsultationbecausethepatientmustbe informedoftheseincreasedrisks.
Installationofthepatientisalsodifficultandthedepth ofthesofttissuessometimesrequirestheuseofaspecific retractor.However,thesurgicalapproachdoesnotseemto influencetherisksevenifsocalledmini-invasivetechniques areused[3].
Despite thelowercorticalindexinobesesubjects, the riskoffractureisnothigher[4].
Ontheotherhandtheprocedurewillbelonger[5]with morebleeding[6]inthesepatients.
Aclassicsurgicalapproachisrecommended,while pay-ingcarefulattention tohemostasis.The risk of instability should be evaluated during the preoperative assessment, andspecific hardwareshould beavailable ifnecessary,or
hips,withariskofhealingdifficulties.Thereisalsoariskof stiffnessduetodeepfibrosis.Inthepresenceofextensive skinretraction,plasticsurgerymaybenecessary.
Neurologicaldiseases
Neurologicaldiseases can be separatedintotwo families, thosethatreducemuscletone(polio,myelomeningocele...) and those that increase it (spastic hemiplegia, Parkinson’s...).
Whenthesediseaseshavebeenpresentsincechildhood, theyresultindysplasiaandevendislocationofthehip,due totheincreaseinstressesthattendtodislocatethefemoral headoutoftheacetabulum.
Whateverthetype,aneurologicaldiseaseincreasesthe risk of dislocation, due tolack of or excessmuscle tone. Animplantthatlimitstheriskofdislocationisusually indi-cated.
This justifies a preoperative neurological assessment includinganelectromyogram(EMG)toensurethatthereis a minimum of muscle tone, and possible management of spasticitywithappropriatetechniques.Spasticityand mus-cleretractioncanbetreatedbytenotomiesduringsurgery, especiallyoftheadductormuscles[7].
Difficulties
due
to
biomechanical
anomalies
of
the
operated
hip
(significant
offset,
coxa
vara,
length
of
the
lower
extremities)
Thelength ofthelower extremitiesandoffset areknown tobeimportantelements inpatientsatisfaction[8,9]and implant survival [10], and if these biomechanics are not respected,stressesoncontactareaareincreased[10].
ThusTHAmustbeplannedbyevaluatinglengthand off-setandthecomponentsthatarebestadaptedtoeachcase mustbechosen.Certainauthorssuggestusingnavigationto closelyevaluateandrestoreoffset[11].
When traditionalhipreplacementsystems(standard or lateraloffset) arenot appropriate, a trochanterotomy or specialcomponentscanbeproposed:
• implantswithmodularstemstorestoreoffset [12],but these are associated with problems of corrosion and breakage dueto themodular design and arealsomore expensive[9];
• hipresurfacingtorespectoffsetandleglengthasmuch aspossible[13,14]butthisrequiressignificanttechnical skill: it also involves a metal onmetal bearing surface whichcouldposeproblems.
Figure1 Significantoffset:lateraldisplacementofthecuptopreservetheleverarm:a:preoperativewithsignificantoffset;b:
postoperative:graftoftheacetabularwalltolateralizethecup.
Finallythecauseofany caseofobliquepelvismustbe determined,andbalanceshouldnotberestoredbyadjusting thelengthoftheoperatedlimb.
Significantlateraloffset
Whenthereissignificantlateraloffsetwithanormalfemoral neck-shaftangle,acertainnumberofsolutionsarepossible topreserveoffsetormuscularstrength.
Fromastrictlyanatomicalpointofviewitispossibleto proposeamodularneck,acustomizedstemwith appropri-ateneckorresurfacing.
Ifatraditionalimplantisusedtherearetwopossibilities torestoreglutealmusclemomentarms:
• preserving the lever arm by lateralization of the acetabular cup, with a graft of the acetabular wall (Fig.1);
• processing with standard implants by trochanterotomy followed by lowering and lateralization of gluteal muscle insertions to preserve satisfactory moment arms.
Coxavara
Avarusfemoralneckisnotcompatiblewiththe biomechan-icsofTHA.Therearetwosolutions:
• respectingthepatient’sanatomywitheithermonoblock hipreplacementswithavarusneck(Fig.2),witha mod-ularneck,acustomizedneckoronceagainresurfacing;
• respecting the biomechanics of the prosthesis: with a stemwitha neck-shaftangle of 130◦, thereisa risk of leglengtheningand/orreducingtheleverarmofthe glu-teusmuscles, witharisk ofinstability. Withthisoption atrochanterotomytostretchoutthemusclesshouldbe considered.
Ankylosis
and
arthrodeses
Arthrodesesmayhavebeenperformedduetojoint deteri-orationfromtrauma,infection,Legg-Calve-Perthesdisease orepiphysiolysis.Ankylosiscanbeduetoheterotopic ossifi-cations.
TheresultsofconversionofhiparthrodesestoTHAare good,witharateofcomplications thatarecomparableto thoseofrevisionTHA[15—17].
Ifarthrodesisisduetoinfection,itisimportantto iden-tifythesourceandobtainnormalizationofbiologicalsigns of infectionbeforedecidinguponsurgery. Duringthe pro-cedure, fivesamples must betakenand thepatient must receiveantibiotherapyforthecausalgermifitisknownor empiricalantibioticsifnot.Antibiotics maybestoppedor continueddependingonintraoperativesampleresults. Nev-erthelessanoldinfectionisnotacontraindicationtoTHA [18].
Figure2 Varusneck:useofamodularneck:a:preoperative:varusneck;b:postoperative:modularneck.
Figure3 Arthrodesis:conversionofarthrodesiswithadualmobilitycup:a:preoperative;b:postoperative.
Whenthearthrodesiswasperformed,itshouldbetaken into account, because if the patient was younger than 15, growth will have considerably modified the morphol-ogyof theproximalfemur, especiallythedevelopmentof thegreatertrochanter,whichaffectsaccesstothegluteus maximus.
Itisessentialtoestimategaitqualityafterarthroplasty, whichrequiresathoroughpreoperativeevaluation[19].
EMGmustbepreformedtoassessthemusclesaswellas magneticresonanceimaging(MRI).Significantweaknessof theglutealmusclescanbeacontraindicationtoTHA. Mus-cularweaknessshouldbeevaluatedinallcases.Itcreates ariskofinstability,whichcanbepreventedbytheuseofa dualmobilitycup.
Morphology should be evaluated on standard X rays, includingassessment oftheleverarm ofthecontralateral hip,andthepossibilityofrestoringittothestiffhip,oflower limblengthdiscrepancies.ACTscanisneededtoevaluate boneloss(BD)intheacetabulumaswellasanydeformities oftheproximalfemur.
The surgical approach is lateral so that osteotomies can be performed. If it is difficult to identify the dif-ferentmuscular planes(lateralvastus, gluteusmedius), a trochanterotomy can be performed, which may be diffi-cult when thegreater trochanter is hypoplastic. An X ray shouldbeperformedifthereisanydoubt.Osteotomyofthe femoralneckinsitutoremovearoundbonefragmentallows dislocationfromthesocketwithoutforcingtheboneends.
Theacetabulumisidentifiedwiththreepointsmakingit easytofind:theovalforamenbelow,theanterior-inferior iliacspineinfront,andtheischiaticnotchbelow.The inter-sectionofthesethreepointscorresponds tothecenterof theacetabulum;reamingbeginshere.Cuporientationcan bedifficultandthepositionofthepelvisinrelationtothe table shouldbecarefully noted.The useof a dual mobil-ity cup shouldbe discussed to prevent dislocations when musclesareweak(Fig.3).
The proximal femur may be deformed, requiring trochanterotomy to expose and identify the medullary canal,ifnecessarywiththehelpofmanualreamers.
In case of significant deformity a cemented prosthesis makesiteasiertoobtainthedesiredorientationand satis-factoryhipbiomechanics.
When stiffness is due to heteroptopic ossifications, which areexcised during arthroplasty, postoperative pre-ventivetreatmentisnecessarytopreventrecurrence:either indometacineorradiationtherapy[20].
Bone
morphology
anomalies
Congenitalhipdislocation
Classification
Therearethreeanatomicaltypesofcongenitalhip disloca-tionaccordingtothepositionofthefemoralheadinrelation tothetrueacetabulum:
• anterior,withaneoacetabulumlocatedaboveandinfront ofthe trueacetabulumwhich itoverlaps/contacts (low dislocationwithcontact);
• intermediary, witha neoacetabulumlocated aboveand separate fromthe middle part of the roof of the true acetabulum(highdislocationwithcontact);
• posteriorwithoutaneoacetabulum(highdislocation with-outcontact).Thefemoralheadissuperoposterior.
TheCroweclassification[21](fourtypes I— IV), which is the most frequently used classification, assesses only the importance of proximal migration of the femoral head.
Dysplasia is often bilateral and maybe symmetric but isoftenasymmetric.Leglengthdiscrepanciesarevery fre-quent.
Indicationsandconsequences
Total arthroplasties are especially indicated for painful arthritisoftheneoacetabulum(contactdislocations).Inthe highformswithoutcontact,painmaydevelopduetocontact betweenthefemoralheadandtheiliacala,whichmaybe seenonCTScan.Symptomsinthespineandkneecontribute totheindication.
Spinalalignmentmayberestoredwitharthroplastyifthe spineisflexible,ifthehipisstableandifleglength discrep-anciesareresolved.Stabilityisnotalwaysobtainedevenif reconstructionissatisfactory[22].
Figure4 Congenitalhip dislocation: customized femoral component, cup in thetrue acetabulum, andacetabular graft: a:
preoperativeAPview;b:postoperativeAPview.
CourtesyofJ.N.Argenson,Marseille.
Maintechniques
Acetabulum. The goal is toinsert the cup into the true acetabulum(arthroplastywithlowering)foranatomical rea-sonsbecausethatiswherethereisacavity,whiletheiliac alaisflat,andfor mechanicalreasonsbecausethecenter ofhiprotationmustbemedializedandtheleverarmofthe glutealmusclesrestoredtocorrectpelvicimbalance.
Small diameter cups must be used with or without cement.It is often necessary toreconstructthe acetabu-lum,especiallyinhighdysplasias.Severaltechniqueshave beenproposed:
• classicshelfaugmentation;
• cotyloplasty [23], withmedialadvancement of the cup andacontrolledfractureofthemedialwall.Theinternal layeroftheperiosteummustbeleftintact,amorselized central autograftmust be performed, andreinforcedif necessary witha metalcage.Great caremustbetaken nottoweakenthecentralregion,whichwouldincrease theriskofsecondarymigration;
• osteotomy of the iliac ala with distal sliding of the detachedfragment.
In certain casesthe cup can beplaced in a high posi-tion.Theprocedureissimpler,butfunctionalresultsseem tobeless good,andcomplicationandloosening rates are higher.Thisisespeciallyindicatedinbilateraldislocations, andwhennomorethan50%ofthecupiscoveredbythetrue acetabulum[24].Inthiscasetheneoacetabulum,whichis arthriticduetocontactdislocationmustbereameduntilthe apexofthecupiscoveredbytheiliacbone.Anadditional shelfaugmentationisnecessary.
Femur. Femoral deformities include coxa valga, excess anteversion, and often small sized femurs (posterior dis-locations). When the femoral deformity is slight, specific so-calledstraightstemsmaybeused.Incaseofadeformity
orapreexistingosteotomy,anosteotomymaybenecessary, acorrectiveosteotomyoracustomizedprosthesis(Fig.4). Femoral lowering and shortening. Lowering the femoral headintothecupmaybeverydifficult.Specifictechniques shouldbeplannedandthesurgeonmustbereadytorespond toanatomicalrealitiesatanymomentduringtheprocedure. The main risk is pulling the sciatic nerve until sciatic palsy, which is why the knee must be flexed throughout surgerysothenervecanbereleased.
Trochanterotomy provides excellent exposure and releases the deep gluteal muscles which favors lowering of thefemur and ofthe greater trochanterat the end of surgery.Fixationofthegreatertrochantermustbeperfect topreventnon-union.
Onemustalwaysbeginwithatotalcapsulectomy.Ifthis doesnotlowerthefemur,twotechniquesarepossible:
• proximal femoral shortening osteotomy, knowing that repeatedosteotomycutsoftheproximalfemurmake it difficulttoinsertthestemintothefemoralshaftwhich isoftenverynarrow.Atrochanterotomyis necessaryto lowerthegreatertrochanterafterwardsinrelationtothe osteotomytopreventitfrombeingtooproximalandtoo nearthepelvis;
• sub-trochanteric shortening osteotomy and sometimes derotation,whichisespeciallyindicatedinhigh disloca-tions[25].Atrochanterotomyisnotnecessaryandbone capital of the proximal femur is preserved, facilitating lowering,andreducing therisk of sciaticparalysis, but increasingtheriskofnon-unionoftheosteotomy[25]. Dysplasia
Therisk ofacetabulardysplasiaistounderestimateitand treat the cavity in a traditional way. If the bearing sur-face of thecup is insufficient, it mayloosenand revision
Figure5 Shelfaugmentationwithtwoscrewsforacetabulardysplasia:a:postoperativeAPview;b:postoperativeprofileview.
surgerymaybenecessary.DuringtheprocedureBDmustbe evaluated,whichisbasicallysuperiorandanterior.
IncaseofminimalBD,areinforcementringthatpresses onthebone maybeusedtoobtainsatisfactorycup orien-tationwithoutagraftiftheentireringisonhealthybone. Divergenceofupto30◦betweenthecupandtheringcanbe tolerated.Theringtransfersstrengthtothebone,whilecup orientationshouldoptimizethebiomechanicsofthebearing couple.
Inothercases,acetabularreconstructionbybonegraftis necessary.Thegraftisusuallyanautograftharvestedfrom the femoral head. When the size of the femoral head is insufficient,abonebankgraftisnecessary(Fig.5).
In case of superior BD, shelf augmentation withscrew fixationshouldbeenough.Theacetabularreamingneedto belocatedintothetrueacetabulum,thenBDisevaluated, shelf augmentation is performed and attached with two screws. Onceshelf augmentation is complete,the spheri-cal shape of the acetabulum must be reconstructed with increasinglywidereaming[24].
In case of significant BD, which is usuallyanterior and superior,theacetabulummustbereconstructedwithabone graftthat restoresan anteriorwallandsufficientsuperior coverage: the definitive cup may be attached to a rein-forcementring, which is pressingupon the reconstructed acetabulum.
Traumaticsequelae
Incase ofpost-traumaticarthritis,twoelements canbea problem: firstBD due totrauma and bone wear,which is usuallyfound in thecolumns andthefloor ofthe acetab-ulum, and on the other hand the presence of fixation screws.
BDistreatedbybonegraftsharvestedfromthefemoral head(andifnecessary anallograftfromabonebank)and stabilizedwithametalcagewithscrewfixation.
Internal fixation screws do not usually disturb the preparationandstabilizationofanacetabularcomponent. Neverthelessitisprobablysafertoplanonremovingthemin caseofaproblem,whichmeansthatthesurgicalapproach usedforinitialinternalfixationshouldbeusedagain(Fig.6). Whenthereareobvioussignificantdifficultiesatwo-step strategycanbeproposed:removalofinternalfixation,then placementoftheprosthesis.
Therateofcomplicationsandrevisionswiththese pro-ceduresarehigherandmechanicalfailuresarelinkedtoa failuretorestoresatisfactoryhipbiomechanics.
Acetabularprotrusio
Acetabular protrusio may be due to a dysmorphic syn-dromeorsecondarytotrauma,Paget’sdisease,rheumatoid arthritis...
Thegoalis torecoverasatisfactorymechanical center ofrotationandtopreventrecurrentprotrusionwhile main-tainingorrestoringequallengthtothelowerlimbs.
Threeprinciplesshouldbefollowed:
• initialresectionofthefemoralnecktofacilitate disloca-tionandextractionofthefemoralhead;
• peripheralacetabularreamingonlytoavoidperforating theacetabularfloor;
• bone graft of the acetabular floor to restore a normal center of rotationby lateralizationusing an acetabular reinforcement ring to prevent secondary cup migration [26](Fig.7).
Femoraldeformities
Morphologicaldeformities
There are two types of morphological deformities of the proximalfemur: congenitaldue todysplasia or secondary
Figure6 Totalhipprosthesisforpost-fractureacetabulararthritis:a:preoperative:internalfixationinplace;b:postoperative:
bonegraftwithareinforcementringwithoutremovalofinternalfixation.
Figure7 Useofagraftandanacetabularreinforcementringinthetreatmentofprotrusiveosteoarthritisofthehip:a:
preop-erative;b:postoperative.
totraumaticinjuries,treatedornotbyinternalfixationor evenanosteotomy.
Thefollowingmechanicalproblemsmustbemanaged:
• stabilize/attachthecomponent;
• controlanteversion;
• restoretheleverarmofthehip;
• respectthelengthofthelowerlimb. Toassessthesecases:
• imagingofthefemurmustbeobtainedonthethreeplanes (besidesAPandprofileviewsXrays,aCTscanshouldbe performedtovisualizethedeformityonthethreeplanes, aswell astheintramedullarycavity,whichcanbe mea-sured);
• longlegstandingAPXrayisalsoneeded.
Thisassessmentwillhelpchoosethebestmethodof fix-ationandstabilization:
• customprosthesis[27];
• shortstemprosthesis;
• revisionimplantafteracomplexosteotomy;
• undersizedcementedprosthesis;
• resurfacingprosthesis;
• amodularimplantforcertainauthors[27,28].
Technicallythedifficultyissometimesremovalof exist-inghardware,butitisusuallyopeningthemedullarycavity inthecorrectdirectionforpositioningoftheimplant.This mayrequireatrochanterotomy[29]forpreparationofthe femoral shaft and optimal positioning of the implant. In theseverycomplexcasesatwo-stagestrategycanbe pro-posed:firstafemoralosteotomytocorrectthedeformity, thenplacementoftheprosthesis[27].
Whenthereissignificantdeformity,especiallyifthereis ahistoryofinfection,resurfacingcanbeproposed(Fig.8). The results of these THA in femoral deformities are comparable to thoseof primaryTHA [30,31]. The results withcemented[32]or uncemented[31]stemsareequally satisfactory: the choice is based onthe surgeon’s prefer-encesandthesituation.
Bonedystrophies
Bonedystrophies(Paget’sdisease,osteoporosis, osteopetro-sis,radiatedbone...)associatestructuralandmorphological
Figure8 Placementofaresurfacingprosthesisincaseofmajordeformityoftheproximalfemurwithahistoryofinfection:a:
preoperative;b:postoperative.
boneanomalies.Thesedystrophiesmaybeassociatedwitha riskofhemorrhage,inparticularinPaget’sdiseaserequiring preoperativemedicalmanagementtocontroltherisk.Poor qualitybonemakesitdifficultytoadapttheintramedullary cavity (neck shaft) to the implant, with a risk of using an undersized implant: a cemented implant adapts bet-tertothepatient’sanatomythananuncementedimplant, becausethelatterrequiresinvasivepreparationofthebone. This isalsotruefor osteoporosis, witha differencein the Youngmodulusbetweentherigidcomponentandthefragile underlyingbonethatistoogreat.Theriskisfracturesand displacementofstressesthatcouldworsenlocal osteoporo-sis.
Failedinternalfixationoftheproximalfemurmay requirerevisionTHA
Unsuccessful internal fixation of per- and subtrochanteric fracturesisoftenduetomechanicalfailure.RevisionTHAis oftentechnicallydifficult.Implantswithmoreextensive dis-talfixation—usuallycemented—areneededforreinsertion of bonytuberosities onto theproximal femur.One should takeadvantageofthefracturetoperformtheequivalentof atrochanterotomy,whichpreservestheglutealmusclesand providesthebestretentionofthesemuscles.
There is some risk of instability, because of repeated surgery.When the acetabulumisintactandthepatientis over80,theuseofan hemi-arthroplastycanbeproposed. Iftheacetabulumisnotintactthefollowingshouldbe pro-posed:
• adualmobilitycupinpatientsovertheageof70;
• inyoungerpatients:THAwithabearingcoupleadaptedto age,andsometimesadualmobilitycupifpatient assess-mentorpreoperativetestssuggestinstability.
Althoughdifferentauthorsemphasizethetechnical dif-ficulties of these arthroplasties, the satisfactory results
[33,34]andthefewpostoperativecomplications[34]make itareliablesolution.
Femoralneckfracturestreatedbyinternalfixation com-plicated by non-union or femoral head necrosis are not technicallydifficult and canbe revised byTHAwithgood results[35].
Conclusion
MostoftheproblemsthatmakeTHAdifficultcanbe antic-ipated by thoroughly understanding the case and good preoperativepreparationincludingdetailedplanning:from analysisof thepatientandhis/hermorphology toanalysis oftherisks.Thispreparationwilllimitintraoperative prob-lems,whichdirectly influence postoperativerisksandthe overallresultofTHA.Allofthisshouldthenbecompleted byinformingthepatientabouttheprocedureandtherisks. Thereis onemajorissue thathas notyet been spoken of:theinfluence ofthesurgeonwithtwoclassicpotential limitations:skillinacertaintypeofsurgeryandsometimesa certain‘‘lackofshape’’.Thesefactors,areconcerns,which mustnotbeignoredandplayaroleinthemanagingcertain difficultpatients.
Disclosure
of
interest
Theauthorsdeclarethattheyhavenoconflictsofinterest concerningthisarticle.
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