Subtrochanteric femoral fractures treated with the Long Gamma3® nail: A historical control case study versus Long trochanteric Gamma nail®

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Original

article

Subtrochanteric

femoral

fractures

treated

with

the

Long

Gamma3

®

nail:

A

historical

control

case

study

versus

Long

trochanteric

Gamma

nail

®

D. Georgiannos

∗

,

V. Lampridis

,

I. Bisbinas

424MilitaryGeneralHospital,PeripheriakiOdosEfkarpias,PC56429,Thessaloniki,Hellas,Greece

a

r

t

i

c

l

e

i

n

f

o

Articlehistory: Received21February2015 Accepted1st_June₂₀₁₅ Keywords: Subtrochantericfractures Gamma3nail Intramedullarynailing Complications

a

b

s

t

r

a

c

t

Background:Gammanailwasdevelopedforthetreatmentofsubtrochanterichipfractures.Despiteits advantagesoverextramedullarydevices,gammanailhasbeenhistoricallyrelatedtosigniﬁcant compli-cations(implantbreakage,femoralfracturesatthetipofthenail).Thereislimiteddatatodetermineif therateofthesecomplicationswasminimizedbyusinganewdesignofthegammanail.Thereforewe performedacasecontrolstudybetweenthelonggamma3nail(LG3N)andthelongtrochantericgamma nail(LTGN)toassessif:(1)thecomplicationrateinthetreatmentofsubtrochantericfracturesusingthe LG3NwaslowerthantheoneusingtheLTGN;(2)thereoperationratewaslowerafterusingtheLG3N. Hypothesis:Thecomplicationrateafterﬁxationofsubtrochantericfractureofthefemurislowerwith LG3NthanwiththeLTGN.

Patientsandmethods:Thisstudyprospectivelyrecordedtheintra-andpostoperativecomplicationsof 75patientswithsubtrochantericfracturestreatedwiththeLG3Nandcomparedthemwiththoseofa historicalcohortof83patientstreatedwiththeLTGN.Thetwogroupswerematchedregardingage, genderandfracturetype.Patientswithopen,pathological,orimpendingfractureswereexcluded. Results:IntraoperativecomplicationsintheLG3Ngroupwerelower(4cases,5.3%)comparedwiththose intheLTGNgroup(9cases,10.8%;P=0.04).Themajorintraoperativecomplicationencounteredwiththe useofLTGNwasfractureofthefemurin3cases.Weencounteredintotal9postoperativecomplications inLG3N(12%)and20ingroupLTGN(24%).Themostfrequentcomplicationinbothgroupswasthecut outofthelagscrew(3casesinLG3Nand7casesinLTGNgroup).Theoverallreoperationratewashigher inLTGNgroup(20.4%vs10.6%;P=0.03).

Conclusion: Asaresultoftheimprovementofitsmechanicalcharacteristics,LG3Nhasprovedasafe andefﬁcientimplantforthetreatmentofsubtochantericfractures.Thenewdesignseemssuperiorto previousgeneration,givingpromisingoutcomes,reducedmechanicalcomplicationrates,andreduced reoperationrate.

Levelofevidence:LevelIII–casecontrolledstudy.

1. Introduction

Thelonggammanail(LGN)wasintroducedin1992 (HOWMED-ICA – OSTEONICS, Rutherford, USA) and was used for sub-trochantericandcombinedtrochanteric-diaphysealfracturesofthe femurwithgood results[1,2].The secondgeneration, thelong trochantericgammanail(LTGN),wasintroducedin1997with mod-iﬁcationsofstandardproximaldiameterof17mm,distaldiameter of 11mm and reduced medio-lateral curvature from10◦ to 4◦

∗ Correspondenceauthor.Tel.:+302310381000;fax:+302313059007.

E-mailaddress:EVIDIM45@hotmail.com(D.Georgiannos).

[3].Thesesignificantlydecreasedtheratesofcomplications[4–6]. Thelatestmodification,theLG3N(StrykerTraumaGmbH, Schon-kichen,Germany),wasintroducedin2003.Incomparisonwithits predecessor,it isnarrowerproximally(15.5mm),hasareduced antecurvatureradiusofR2.0mofthefemoralshaftandthesame medio-lateralcurvature,butwithitsapexpositionedmoredistally. Thelagscrewshapehasalsobeenimprovedintheareaofthethread andthecuttingflutesatthetipofthescrew.

Theuseofintramedullarydeviceshasbeenthegoldstandardof treatmentofsubtrochantericfracturesintherecentyearsduetoits advantagesoverextramedullarydevices[7].Despiteitsadvantages, intramedullarynailshavebeenrelatedtosigniﬁcantcomplications, suchasimplantbreakageandfemoralfracturesatthetipofthenail, http://dx.doi.org/10.1016/j.otsr.2015.06.018

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Fig.1.RightfemoralsubtrochantericfractureSeinsheimertypeIII(A)treatedwithaLG3N(B).

whicheventuallyrequirerevisionsurgery[8–11].However,there islimitedevidencespeciﬁcallyevaluatingtheoutcomesfollowing theuseofLG3Ninthetreatmentofsubtrochantericfractures.

Thepresentcasecontrolledstudywasprospectivelydesignedto comparethecomplicationandreoperationratesinthetreatmentof subtrochantericfracturesusingtheLG3Nwiththoseofahistorical cohorttreatedwiththeLTGN.Thegoalofthestudywastoanswer thefollowingquestions:

• isthecomplicationrateinthetreatmentofsubtrochanteric frac-turesusingtheLG3NlowerthantheoneusingtheLTGN? • IsthereoperationratelowerafterusingtheLG3N?

OurworkinghypothesiswasthattheLG3Nresultedinalower incidenceofintra-andpost-operativecomplicationscomparedto LTGN.

2. Patientsandmethods 2.1. Patients

Between2007and2010,75patientswithsubtrochanteric frac-tures,weretreatedsurgicallywithLG3N(groupLG3N)(Fig.1).The

studywasaprospectivenon-randomizedstudycomparingwith ahistoricalcontrolgroup(groupLTGN),consistedof83patients treatedwithLTGN(Fig.2)throughtheperiod2000–2005.

Closedfemoral fracturesof the subtrochanteric regionwere included in the study and classified according to Seinsheimer classification[12](Table1).Exclusioncriteriawereopenand patho-logicalfractures,prophylacticnailing,andfracturestreatedatthe firstyearaftertheintroductionofbothimplantsintheDepartment (excludingthelearningcurveperiodforthesurgeons).

2.2. Methods

Alloperationswereperformedby4orthopaedicspecialistswith globalknowledgeoftheprinciplesofintramedullarynailingand experienceintheuseofgammanails.Themethodoftreatmentwas similartobothgroups.Patientswerepositionedsupineontraction tableandclosedreductionoffractureobtainedunderfluoroscopic control.AllLTGNandLG3Nusedweremadeoftitaniumalloy.The entrypointwasthesameforbothtypesofnail.Itwasfirst identi-fiedbypalpationwiththesurgeon’sindexfingeratthetipofgreater trochanter,atthejunctionoftheanteriorthirdandposteriortwo thirdsthroughasmallskinincision,followingbyfluoroscopic con-trolofthepositionoftheowl.Intramedullarycanalswerereamed

Fig.2. RightfemoralsubtrochantericfractureSeinsheimertypeIII(A)treatedwithaLTGN.Reductionandlagscrewpositionconsideredasproper(B).3mpostopAP

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Table1

FracturepatternaccordingtoSeinsheimerclassiﬁcation[12].

Type Characteristics GroupLG3N(n=75) GroupLTGN(n=83) Statisticalsigniﬁcance I Undisplacedfractureswithlessthan2mmdisplacementofthe

fracturedfragments

– – NS

II Two-parttransverseorspiralfractureswiththelesser trochanterattachedtotheproximalorthedistalfragment

17(22.66%) 20(24.09%) NS

III Three-partspiralfracturesinwhichthelessertrochanteris partofthethirdfragmentorbutterﬂyfragment

31(41.33%) 35(42.16%) NS

IV Comminutedfractureswithfourormorefragments 10(13.33%) 9(10.84%) NS V Subtrochanteric-intertrochantericfractures,includingany

subtrochantericfracturewithextensionthroughthegreater trochanter

17(22.66%) 19(22.89%) NS

LG3N:longgamma3nail;LTGN:longtrochantericgammanail;NS:notsigniﬁcant.

Table2

Demographicdata.

Variables GroupLG3N(n=75) GroupLTGN(n=83) Statisticalsigniﬁcance

Age 59(29–74) 62(48–76) NS

GenderratioF:M 2.5:1 2.8:1 NS

Mechanismofinjury

Fallfromgroundlevel 73% 75% NS

Roadtrafﬁcaccident 18% 17% NS

Fallfromheight 9% 8% NS

Mortalityrate(1year) 18.4%(n=12) 21.9%(n=16) NS

LG3N:longgamma3nail;LTGN:longtrochantericgammanail,NS:notsigniﬁcant.

Table3

Intraoperativevariables.

GroupLG3N GroupLTGN Statisticalsigniﬁcance

Waitingtime,hours(mean) 12–58(24) 10–52(22) NS

Surgicaltime,minutes(mean) 19–60(43) 20–85(48) NS

Fluoroscopytime,seconds(mean) 25–65(34) 27–87(45) S(P<0.001)

LG3N:longgamma3nail;LTGN:longtrochantericgammanail;NS:notsigniﬁcant;S:signiﬁcant.

upto13mmdistallyforbothnailsandproximallyupto15.5mm and17mmforG3NandTGNrespectively.Insertionofthenailwas donebyhandwithoutanyforceandwithouttheuseofamallet. Lagscrewwasinsertedata130◦angle,optimallyinaposition infe-riorlytotheneckintheAPplaneandcentrallyinthelateralplane. Distallockingwasachievedwithfree-handtechnique.Allpatients weremobilizedwithfullweightbearingontheﬁrstpostoperative day.

2.3. Methodsofassessment

Theprimaryoutcomescollectedinthepresentstudywere intra-andpost-operativecomplications.Patients’demographics, mech-anismofinjury,fracturetype,waitingtimetosurgery,operation time,ﬂuoroscopytime,durationofhospitalstayandmortalityrate werealsorecordedassecondaryvariables.Patientswerefollowed upat6weeks,3monthsand1yearwithclinicalandradiological assessment.X-raysassessedforfracturereductionandthetip-apex distance(TAD)calculated(maximumfollow-upat3years).

2.4. Statisticalanalysis

Statisticalanalysisusingtheunpairedstudent’st-testandthe Fisher’sexacttestwereappliedtoevaluatesignificantdifferences betweenthetwogroups(SPSS,version11.5,SPSSInc.Chicago, Illi-nois,USA).Statisticalsignificancewasdefinedatthe5%(P<0.05) level.Asamplesizecalculationwasdoneusingalphaat5%andbeta powerat80%withabaselineproportionat20%,thestudyrequired 52casesineacharmtodetecta20%differenceincomplicationrate.

3. Results

Thedemographicdataofthepatients,theintra-operative

vari-ables and theradiological assessment areshown in Tables 2–4

respectively.

FourcomplicationsingroupLG3N(5.3%)and9ingroupLTGN (10.8%) werereportedintraoperatively(Table5).Thedifference betweenthetotalnumberofintraoperativecomplicationsinthe 2groupswasstatisticallysigniﬁcant(P=0.04).Themajor compli-cationsencounteredwiththeuseofLTGN,were3intraoperative fracturesoffemur.In2cases,thefracturewasanundisplacedcrack ofthelateralcortexofthefemoralshaftjustdistallytothetipof nail.Theseweretreatedconservativelywithnon-weightbearing mobilizationuntilcallusformationwasseenonX-rays.Onecaseof greatertrochanterfracturewastreatedwithpartialweightbearing mobilizationfor6weeks.Nofemoralfractureswereencountered intheLG3Ngroup.

Weencounteredintotal9postoperativecomplicationsinGroup LG3N(12%)and20inGroupLTGN(24%)(Table6).Therewas sig-niﬁcantdifferencebetweenthe2groups(P=0.04).Thedifferences

Table4

Radiologicalassessment.

Variables GroupLG3N GroupLTGN Statisticalsigniﬁcance Radiologicalreduction

Anatomic 18(24%) 19(22.9%) NS Acceptable 34(45.3%) 39(47%) NS Poor 23(30.7%) 25(30.1%) NS

TAD 18(12–25) 17(13–24) NS

LG3N:longgamma3nail;LTGN:longtrochantericgammanail;NS:notsigniﬁcant; TAD:tip-apexdistance.

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Table5

Intraoperativecomplications.

Complications GroupLG3N(n=75) GroupLTGN(n=83) Statisticalsigniﬁcance

Femoralfracture – 3 S(P=0.03)

Perforationofacetabulum(bythethreadedguidewire) 4 6 NS

Total 4(5.33%) 9(10.84%) S(P=0.04)

Table6

Postoperativecomplications.

Complications GroupLG3N (n=75) GroupLTGN (n=83) Statisticalsigniﬁcance

Femoralfracture – – 2 2.4% NS

Nailbreakage – – 2 2.4% NS

Lagscrewcutout 3 4% 7 8.4% S(P=0.03)

Distalscrewbreakage 1 1.3% 2 2.4% NS

Lossofreduction 2 2.2% 3 3.6% NS

Non-union 3 4% 4 4.8% NS

Total 9 12% 20 15.6% S(P=0.04)

betweenthe 2 groups for postoperativefemoral fractures, nail breakage,distalscrewbreakage,lossofreductionandnon-union

werenot signiﬁcant.The differencein lagscrew cut out

com-plicationwas statisticallysigniﬁcant(P=0.03).Femoral fracture occurredpostoperativelyin 2patientsofgroupLTGN,following afall.Bothsustainedafracturejustdistaltothetipofthenailand weretreatedwithanopenreductionandinternalﬁxation.Intwo cases,aLTGNfailedatthejunctionofnailwiththelagscrew,4 and6monthspostoperatively,duetodelayedunion.Thenailswere revisedtoDCSandthefractureshealeduneventfully4monthsafter revisionoperation(Fig.3).

Themostfrequentcomplicationinbothgroupswasthecut-out ofthelagscrew(3and7casesrespectively)whichresultedin re-operationin3casesofgroupLG3N(1totalhipreplacementand 2hemiarthroplasties)andin6 casesof groupLTGN(1totalhip replacement,3hemiarthroplastiesand2DCS)(Fig.4).Theposition ofthelagscrewwasconsideredoptimal(inferiorlyinAP/centrally inlateralplane)in2outofthe3failedcasesingroupLG3Nandin 5outofthe7failedcasesingroupLTGN(P=0.04).IngroupLG3N, lossofreductionwasoccurredin2cases(treatedwithDCS)and nonunionin3casesofsubtrochantericfracturewhichweretreated

byrevisionwithaLG3Nandbonegrafting.IngroupLTGN,nonunion ratewashigher(4cases)andallweretreatedwithrevisionnailing andbonegrafting.Lossofreductionoccurredin3cases,whichwere treatedwithopenreductionandﬁxationwithaDHS.

Theoverallre-operationratewas10.6%(8cases)forgroupLG3N and20.4% (17cases)for groupLTGN,asitisshown inTable7. Thedifferenceofre-operationratesbetweenthetwogroupswas signiﬁcant(P=0.03).

4. Discussion

OurstudyprovidesnewdataregardingtheuseofLG3Nin sub-trochantericfractures.Thelaterdesignseemssuperiortoprevious generations,withreducedintraoperativeandpostoperative com-plicationrates.

Themainlimitationofthisstudyistheuseofahistoricalcohort as the control group. However, thetwo groups were matched regarding theage,gender and fracture type. Alltheoperations wereperformedbythesamegroupofexperiencedsurgeonsand theoperationswithinthelearningcurveperiodwereexcluded, thuswebelievethatthisincreasesthestrengthofthestudyand

Fig.3. Preop(A)andpostop(B)APradiographsofasubtrochantericfractureSeinsheimerIVofleftfemurtreatedwithLTGN.Reductionconsideredaspoor.4mpostopAP

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Fig.4. SubtrochantericfractureSeinsheimerVofrightfemurtreatedwithaLTGN(A).APandLatview4mpostop,revealedcutoutofthelagscrew(B,C).Fixationrevised

withaDCSandthefracturehealeduneventfully(D).

minimizedtheimpactofthislimitation.Thesecondlimitationis thenumber of patientswithdrew before theﬁnal follow-up at oneyearduetomanypatientswithconcomitantillnesses affect-ingtheirgeneralhealthand ameanmortalityrateat1–yearof 20.1%.Nonetheless, drop-outratewascomparable betweenthe twogroups,minimizingbiasintheinterpretationoftheresults,and sampleandpowercalculationsconﬁrmedthevalidityofourresults. Finally,comparingourserieswiththeliteraturewaschallenging, assubtrochanteric fracturesarenotwelldifferentiatedfromthe otherpertrochantericfemoralfracturesandthereisalackofstudies regardingLG3Nintheliterature.

Fractureofthefemoralshaftisaknowncomplicationandin previousstudies,upto8%incidencehasbeenreportedforTGN

[1,4,6,13,14].Fracturearoundorbelowthetipof thenail seem tobeduetostressriserscreatedbytherigidityoftheimplant andcompressiveloadsatthetipofthenail[3].Inthisstudy,5 femoralfractures(6.05%)occurredinthehistoricalcohortofLTGN (3intraoperativelyand2postoperatively).Nofractureofthefemur occurredintheLG3Ngroup,whichislowerthantheresultsfrom otherstudiesonG3N,whichhadareportedincidenceof1%[15,16]. Insufﬁcientreamingoruseofahammercouldincreasetheriskfor thiscomplication[1,3].Aswestrictlyadheredtotheoriginal surgi-caltechniqueandtheindustrialrecommendations,weattributed thelowerrateofthefemoralshaftfracturestothemodiﬁcations andimprovementofmechanicalcharacteristicsofthenewdesign, namelythedecreasedproximaldiameterwhichrequiresless ream-ingandthedistallypositionedapexofthemedio-lateralcurvature ofthenailwhichreducesthethree-pointloadingatthefemoral shaft[3].

Breakageofthegammanailatthejunctionofthenailwiththe lagscrewisreportedintheliteraturewithanincidenceofupto

5.7%[8,9,16].Inthis study,noneoftheLG3Nfailed,in contrast with2LTGNbrokennails(2.4%).Itisknownthattheweakpointof thisimplantisaroundtheinsertionholeforthelagscrewwhere thecross-sectionalareaisreducedbyapproximately73%.Thisisa criticalzonewhereforcescomingfromthefemoralneckare trans-mittedtothediaphysealnail[8].Webelievethatthedecreased incidenceoffailureofthenailwasattributedtothereductionof thelagscrewdiameterfrom12mmto10.5mm.Thereforethe aper-tureissmallerandthusthenailwouldbethickerinthisareaand lesspronetofailure.Delayedunion/nonunionatthefracturesite wasthetriggerfactorforboththeimplantfailures.Thecauseof breakagewasmetalfatigueduetodynamicstress[9,17].

Themostfrequentlyoccurringcomplicationwasthecutoutof thelagscrewthroughthefemoralhead,4%and8.4%ingroupLG3N andgroupLTGNrespectively.Our resultsweresimilarwiththe resultsofotherstudiesshowinganincidencerateupto9.72%forthe TGNandupto4%forG3N[1,3,5,6,14,15,18].Lagscrewcut-outhas beenshowntobedependentonthepositionofthescrewwithinthe femoralhead.OptimizingtheTADiscriticalinpreventingﬁxation failurewhenusinganextramedullaryslidinghipscrewtoﬁx peri-trochantericfractures[19].Arecentstudysuggeststhatplacement ofthelagscrewofthegammanailinferiorlyintheAPplaneand centrallyinthelateralplane(achievingTAD<25mm)maximizes biomechanicalstiffnessandload-to-failure[20,21].Thepositionof thelagscrewwasconsideredoptimal(inferiorlyinAP/centrallyin lateralplane)in2outofthe3failedcasesingroupLG3Nandin5out ofthe7failedcasesingroupLTGN(P=0.04).Intheremainderofthe failedcases,thepositionwasconsideredsuboptimal(centrallyin AP/centrallyoranteriorlyinlateralplane).Therefore,weattributed thelowerrateofcutoutcomplicationtotheimprovementoflag screwdesign,especiallyintheareaofthethreadandthecutting

Table7

Re-operationdata.

Data Femoralfracture Implantfailure Lagscrewcutout Lossofreduction Non-union

GroupLG3Nn=8(10.6%) – – 3 1THA 2DCS 3LG3N&graft

2bipolar GroupLTGNn=17(20.48%) 2 1ORIF 2revision

DCS 6 1THA 3Bipolar 2DCS 3DHS 4 3LGTN&graft 1Bipolar 1LGTN S(P=0.03)

LG3N:longgamma3nail;LTGN:longtrochantericgammanail;S:signiﬁcant;ORIF:openreductionandinternalﬁxation;DCS:dynamiccompressionscrew;DHS:dynamic hipscrew.

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ﬂutesatthetipofthescrew.Thisdesign offerssuperiorcutting behaviorduringlagscrewinsertion,providingverylowinsertion torque.Thethreaddesignalsooffersexcellentgripinthe cancel-lousboneofthefemoralheadandstrongresistanceagainstcutout. Theoptionofthehelicalbladethatexistsinotherintramedullary

deviceshasimprovedbiomechanical propertiesandcanfurther

decreasethecutoutrate[22].

Qualityofreductionofsubtrochantericfracturesisan impor-tantfactorthat interferessigniﬁcantlytopreventcomplications suchascutout,implantbreakageandnonunion.Typeofreduction frequentlyobtainedwithsubtrochantericfractureisratherpoor oracceptablethananatomic[1].Ourresultsregardingqualityof reductionwerenotstatisticallydifferentbetweenthetwogroups. Theywerecomparabletoresultsofotherstudies[23],sowebelieve thattheuniversallyacceptedinterferenceofpoorreductionto post-operativecomplications,althoughstillpresent,wasdramatically decreasedinourstudy.

The rateof re-operation after complications with the LG3N was 10.6%, which was higher than the 5.56% rate reported in otherstudy,attributedtoinclusion ofsubtrochanteric fractures only[24].Therateofimplant-relatedcomplicationsthatrequired re-operationafterprimaryuseoftheLTGNwas20.48%.Itisin accor-dancewithpreviouslyreportedresultsrangingfrom8%to17.6%

[5,13,14,18,24,25]. 5. Conclusion

Withinthelimitsofthisstudy,gamma-3nailhasbeenproved asafeandefﬁcientimplantforthetreatmentofsubtrochanteric fractures.Althoughappropriatereductionisstillprerequisitefor goodresults,thenewdesignseemssuperiortopreviousgeneration, givingpromisingoutcomesandreducedmechanicalcomplication andreoperationrates.

Disclosureofinterest

Theauthorsdeclarethattheyhavenoconﬂictsofinterest con-cerningthisarticle.

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