A critical analysis of limb symmetry indices of hop tests in athletes after anterior cruciate ligament reconstruction

Available

online

at

ScienceDirect

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Original

article

A

critical

analysis

of

limb

symmetry

indices

of

hop

tests

in

athletes

after

anterior

cruciate

ligament

reconstruction:

A

case

control

study

A.

Gokeler

_,

_W.

_Welling

_,

_A.

_Benjaminse

_,

_K.

_Lemmink

_,

_R.

_Seil

_,

_S.

_Zaffagnini

c_{HanzeUniversityAppliedScience,SchoolofSportStudies,Groningen,TheNetherlands}

d_{Départementdel’AppareilLocomoteur,CentreHospitalierdeLuxembourg,Luxembourg,Luxembourg} e_{RizzoliOrthopaedicInstitute,UniversityofBologna,Bologna,Italy}

a

r

t

i

c

l

e

i

n

f

o

Received25January2017 Accepted27February2017 Keywords:

Anteriorcruciateligament Returntosports Hoptest Limbsymmetry

a

b

s

t

r

a

c

t

Background: Hoptestsarefrequentlyusedtodeterminereturntosports(RTS)afteranteriorcruciate ligamentreconstruction(ACLR).GiventhatbilateraldeficitsarepresentafterACLR,thismayresultina falselyhighlimbsymmetryindex(LSI),sinceLSIiscalculatedasaratiobetweenthevaluesofthelimbs. Hypothesis:AthletesafterACLRwouldachieveLSI>90%forthehoptest.Secondly,athletesafterACLR demonstratedecreasedjumpdistanceonthesinglehopfordistance(SLH)andtripleleghopfor dis-tance(TLH)anddecreasednumberofhopsforthesidehop(SH)forbothinvolvedanduninvolvedlimbs comparedtonormativedataofsex,ageandtypeofsportsmatchedhealthyathletes.

Materialsandmethods: Fifty-twopatients(38malesmeanage23.9±3.5years;14femalesmeanage 21.7±3.5years)whohadundergoneanACLRparticipatedinthisstudy.Patientsperformedthe3hop testsatameantimeof7monthsafterACLR.Hopdistance,numberofsidehopsandLSIwerecompared withnormativedataof188healthyathletes.

Results:Thedifferencesbetweentheinvolvedlimbandtheuninvolvedlimbweresignificantinallhop tests(SLHP=0.003,TLHP=0.003,SHP=0.018).Forfemales,onlysignificantbetweenlimbdifferences werefoundintheSLH(P=0.049).ForboththeSLHandtheTLH,significantdifferenceswerefound betweentheinvolvedlimbandthenormativedata(males;SLHP<0.001,TLHP<0.001;females;SLH P<0.001,TLHP=0.006)andbetweentheuninvolvedlimbandthenormativedataforbothmalesand females(males;SLHP<0.001,TLHP<0.001;females;SLHP=0.003,TLHP=0.038).FortheSH,only sig-nificantdifferenceswerefoundbetweentheinvolvedlimbandthenormativevaluesinmales(P=0.033). Conclusion:AthleteswhohaveundergoneanACLRdemonstratebilateraldeficitsonhoptestsin com-parisontoageandsexmatchednormativedataofhealthycontrols.UsingtheLSImayunderestimate performancedeficitsandshouldthereforebeanalyzedwithcautionwhenusedasacriterionforRTS afterACLR.

Levelofevidence:III,casecontrolstudy.

©2017ElsevierMassonSAS.Allrightsreserved.

1. Introduction

Theclearancefor fullreturntosports(RTS) toathletesafter

anterior cruciate ligament reconstruction (ACLR) by physicians

andrehabilitation specialistsisa criticalpoint towardstheend

ofanextensivecourseofrehabilitation[12].Unfortunately,

deci-sionmakingtoallowapatienttoRTSandunrestrictedphysical

activityafterACLRisoneofthemostchallenginganddifficult

deci-∗ Correspondingauthor.

E-mailaddress:a.gokeler@rug.nl(A.Gokeler).

sions clinicianshave tomake [1]. In a review ofthe literature,

40%ofstudiesfailedtouseanycriteria,andonly32%ofstudies

usedtimepost-surgeryasthesolecriteriontodeterminewhenan

athletemaybereadyforRTSafterACLR[2].Workpresentedin

thispaperistheresultofaninternationalcollaborationbetween

orthopaedicsurgeons,sportandhumanmovementscientistsand

physicaltherapistswiththeobjectivetoreduceACLinjuryrates,

enhancequalityoflifeforpatientsafterACLinjuryandsurgeryand

decreasetheincidenceofosteoarthritis.

Clinicians must chooseteststhat are objective, reliable,and

valid.WithregardtoACLR,objectiveoutcomemeasuresinclude

clinicaland functional performancetests (FPT) andare popular

http://dx.doi.org/10.1016/j.otsr.2017.02.015

A.Gokeleretal./Orthopaedics&Traumatology:Surgery&Research103(2017)947–951

duetotheirabilitytoquantifykneefunction[3,4].TheFPTwere

developedtosimulatesportspecificmovementsinacontrolled

fashion.

HoptestsarethepreferredtypeofFPTduetoutilizationofthe

uninjuredlimbasacontrolforbetweenlimbcomparisons,andasa

referenceagainstwhichdischargefromrehabilitationandRTSmay

bedetermined[5,6].Hoptests,likethesinglehopfordistance(SLH),

thetriplehopfordistance(TLH),thecrossoverhopfordistance,

andthe6-mtimedhop,areFPTwithextensiveresearch

suppor-tingtheirreliability[3,7,8,9].Researchershaverecommendedthat

FPTshouldalsoincludeanendurancehoptestlikethesidehop

(SH)[10].Itiscommontocalculatealimbsymmetryindex(LSI)

calculatedashoptestperformanceoftheinvolvedlimb/hoptest

performance ofthe uninvolved limb×100% [4,11,13]. LSI

crite-ria>90%areoftenusedascut-offscoresforRTS[10,14].However,

therearesomeconcernsregardingtheuseoftheuninvolvedlimb

asa referencefor theinvolved limb. Abnormalmovement

pat-ternshavebeenreportednotonlyfortheinvolvedlimbbutalso

theuninvolved limbafterACLinjury [15].Additionallybilateral

neuromusculardeficitshavenbeenreportedafteranACLinjury

[16–20].

Hence,abilateraldeficitmayleadtoafalselyhighLSI,sinceLSI

iscalculatedasaratiobetweenthevaluesofthelimbs.An

ath-letemayhaveperfectlimbsymmetryandyetbeunderpreparedto

competebecausebothextremitiesaremuchweakerormorepoorly

controlledthanahealthyathlete.Myersetal.recentlycautioned

professionalstopurelyrelyupontheLSIfortheassessmentofhop

testperformance[21].ThestudyofMyersetal.provided

normat-ivevaluesfortheSLHandTLHtestthatwerebasedonsex,typeof

sportandlevelofcompetition[21].Gustavssonetal.havereported

dataontheSH[22].

Thepurposeofthecurrentstudywasthereforetocomparethe

resultsof3differenthoptestsinpatientsafterACLRtonormative

dataofhealthyathletes.Itwasourhypothesisthatathletesafter

ACLRwouldachieveLSI>90%forthehoptest.Secondlyhowever,

athletesafterACLRdemonstratedecreasedjumpdistanceonthe

SLHandTLHanddecreasednumberofhopsfortheSHforboth

involvedanduninvolvedlimbscomparedtonormativedataofsex,

ageandtypeofsportsmatchedhealthyathletes.

2. Materialsandmethods

2.1. Subjects

Fifty-twopatientswhohadundergoneanACLRparticipatedin

thisstudy.Therewere38malepatients(meanage23.9±3.5years)

and14femalepatients(meanage21.7±3.5years)who

partici-patedinvariouslevelI–IIsportspriortoinjury.Normativedata

from188healthyathleteswereusedascontrols(Table1).

Inclu-sioncriteriafor thepatientswere:isolated ACLR,noassociated

meniscuslesionrequiringrepairorpartialmeniscectomyor

carti-lagelesion,normallimbalignmentaswellasnorelevantprevious

surgery atany otherjointof thelimbs.Exclusion criteriawere

jointeffusion,varusthrustoftheknee,>50%removalofthewidth

ofthemeniscus,grade3ruptureofthecollateralligaments,

con-comitantligamentinjuriestotheposterolateralor–medialcorner,

traumaticordegenerativecartilagelesions>2cm2_,surgical

proce-duresorinjuriestocontralaterallimboranyhistoryofneurological,

vestibularorvisualimpairment.AnarthroscopicACLRwith

antero-medialportaltechniquewasperformedonallpatientsbythesame

2surgeons.Allthepatientsunderwentastandardizedearly

rehabil-itationprotocol.Thepatientsperformedthetestbatteryonaverage

at7months(range6.7–7.4)followingACLR.Thestudyprotocolmet

theethicalstandardsrequiredbythegoverningEthicsCommittee

andinformedconsentwasobtainedfromallsubjectspriortodata

collection.

Table1

Demographicsofpatientsandcontrolgroup.

ACLRgroup Controlgroup

Males Females Males Females

Myersetal., 2014 Gustavsson etal.,2006 Myersetal., 2014 Gustavsson etal.,2006 Numbersubjects 38 14 87 9 85 6

Age(years,range) 24.0±3.6

(17–30) 21.7(17–28)±3.5 19.2(17–24)±(NR) 29.0±4.0(NR) 19.3(17–22)±(NR) 26.0(NR)±4.0 Weight(kg) 67.6±26.7 51.0±16.4 84.0±10.0 (NR) 61.0±6.0 (NR) Typegraft HT(28),PT(8), ST(2),AG(1) HT(14) Timepost-surgery (months) 6.7±1.2 7.4±1.2 Typesports(numberof

subjects) Football(32) Basketball(2) Badminton(1) Korfball(1) Fitness(2) Football(4) Basketball(1) Handball(4) Tennis(2) Korfball(2) Hockey(1) Football, Basketball Football, Basketball

Isokineticpeaktorque extension60◦_/s(Nm) (LSI) Involved 235.9±42.4 Uninvolved 262.5±38.5 (90.0%) Involved 161.4±34.1 Uninvolved 183.1±28.9 (88.0%) Isokineticpeaktorque

flexion60◦_/s(Nm) (LSI) Involved 132.3±22.5 Uninvolved 138.0±22.5 (96.3%) Involved 86.4±19.2 Uninvolved 95.9±17.8 (90.1%) IKDC 85.4±11.0 83.6±6.1

ACLR:anteriorcruciateligamentreconstruction;controlgroup:derivedfromnormativedata;NR:notreported;HT:hamstringtendon;PT:patellartendon;AG:allograft; ST:synthetictendon;LSI:limbsymmetryindex.

A.Gokeleretal./Orthopaedics&Traumatology:Surgery&Research103(2017)947–951

2.2. Procedure

Datafrom3unilaterallowerextremityhoptestswerecollected

thatincludedtheSLH,TLHandtheSH.TheSLHandTLHtestswere

conductedasdescribedbyNoyesetal.[11].About5–10practice

tri-alswereperformedasrelativehighnumberofpracticetrialsbased

onpreviousresearchthat indicated thathopdistanceincreases

withpractice[9].Betweenpracticeandcommencementoftrials,

patientshada3-minutepause.FortheSH,thesubjectsstoodon

thetestleg,andjumpedfromside-to-sidebetweentwoparallel

stripsoftape,placed40cmapartonthefloor.Thesubjectswere

instructedtojumpasmanytimesaspossibleduringaperiodof

30s.Thenumberofsuccessfuljumpsperformed,without

touch-ingthetape,wasrecorded[22].Betweenhoptrials,patientswere

givena30srestperiod.Patientsperformedallhoptestfirstwith

theuninvolvedlimbandorderoftestingwasSLH,TLHandfinally

SH(videoinsupplementarymaterial).

Forall3hoptests,alimbsymmetryindex(LSI)wascalculated

asthemeanscoreforinvolvedlimb/uninvolvedlimb×100%.

Nor-mativedataforhealthy controls(CTRL),derived from2studies

[21,22]wereusedforcomparisonwithpatientsafterACLR.The

studyofMyersetal.providednormativevaluesforeachhoptest

thatwerebasedonsex,typeofsportsandlevelofcompetition[21].

Inaddition,theyfoundnoclinicallyrelevantdifferencesbetween

dominantandnon-dominantlimbsinhealthyathletesnordidthey

finddifferencesbetweenathletesthatplayedfootballorbasketball

[21].Thesefindingsallowforbetweengroupcomparisons.Forthe

SH,datawerederivedfromtheonlystudyavailableintheliterature

tothebestoftheknowledgeoftheauthors[22].

2.3. Statisticalanalysis

Alldatawerenormallydistributed.Pairedsamplet-testswere

usedtoinvestigatethedifferencebetweenthedistanceand

num-berofhopsoftheinvolvedlimbanduninvolvedlimb.Inaddition,

wecomparedtheinvolvedanduninvolvedlimbsoftheACLRgroup

tothenormativedataofalargesampleofhealthyathletes[21,22].

Amatchedsubjectdesignwasusedtocomparethepatientgroup

withacontrolgroupbasedonsex,ageandtypeofsports.The

nor-mativedatawerepresentedforthedominantlimbastherewereno

clinicalrelevantdifferencesbetweendominantandnon-dominant

limbs[21].Todeterminedifferencesbetweenlimbs(involvedand

uninvolved)andgroups(ACLRandhealthycontrolgroup),a2×2

ANOVAwasconductedforeachhoptest.Inaddition,clinically

rel-evantdifferencesweredeterminedbasedonthestandarderrorof

measurement(SEM)ofhealthyathletesfortheSLHandTLH.The

SEMfortheSHhasnotbeenreportedintheliteraturetothebest

knowledgeoftheauthors.

3. Results

ThemeanLSIwas95.4%forthe3hoptests.Eighty-threepercent

ofthepatientspassedcriteriasetasLSI>90%fortheSLHand86.8%

respectivelyfortheTLH.InTable2,theLSIandtheabsolute

differ-encesbetweentheinvolvedlimbandtheuninvolvedlimbinscores

ontheSLH,TLHandSHofthepatientsafterACLRpatientsare

pre-sentedformalesandfemalesseparately.Formales,thedifferences

Table2

Mean(SD)forthe3differenthoptestsinpatientsafterACLreconstruction.

Males Females SLH Involvedlimb(cm) 156.5±23.5 131.3±13.7 Uninvolvedlimb(cm) 164.0±23.09 136.0±13.8 LSI(%) 95.4 96.5 Pvalue 0.003* _0.049* TLH Involvedlimb(cm) 506.3±71.4 426.5±49.2 Uninvolvedlimb(cm) 527.9±65.6 439.2±49.8 LSI(%) 95.9 97.1 Pvalue 0.003* _0.082 SH

Involvedlimb(numberhops) 50.4±12.6 39.6±14.0 Uninvolvedlimb(numberhops) 54.0±12.5 41.9±11.6

LSI(%) 93.3 94.5

Pvalue 0.018* _0.027*

SLH:singleleghoptest;TLH:tripleleghoptest;SH:sidehoptest;LSI:limb sym-metryindex.

*_{Denotesstatisticalsignificance.}

betweentheinvolvedlimbandtheuninvolvedlimbwere

signifi-cantforallhoptests(SLHP=0.003,TLHP=0.003,SHP=0.018).For

females,onlysignificantdifferenceswerefoundintheSLHbetween

theinvolvedlimbandtheuninvolvedlimb(P=0.049).The

differ-encesbetweentheinvolvedanduninvolvedlimbsfortheSLHand

TLHwereallwithintheSEM(4.5–7.9cmfortheSLH,15.4–23.2cm

fortheTLH)exceptforfemalesintheTLH,whodemonstrateda

side-to-sidedifferenceof12.7cm.

NormativedataandtheSEMfortheSLH,TLHandSHare

pre-sentedinTable3.InTable4,thedifferencesbetweentheinvolved

limb,theuninvolvedlimbandthenormativedataarepresentedfor

the3hoptestsseparately.ForboththeSLHandtheTLH,significant

differenceswerefoundbetweentheinvolvedlimbandthe

normat-ivedata(males;SLHP<0.001,TLHP<0.001;females;SLHP<0.001,

TLHP=0.006)butalsobetweentheuninvolvedlimbandthe

nor-mativedataforbothmalesandfemales(males;SLHP<0.001,TLH

P<0.001;females;SLH P=0.003,TLH P=0.038). Thedifferences

between ACLRgroupand controlswere alsoclinically relevant

withshorterjumpdistancesfortheSLH(involvedmales35.5cm,

females17.6cm;uninvolvedmales28.0cm,females13.0cm)and

fortheTLH(involvedmales125.7cm,females43.5cm;uninvolved

males104.1cm, females 30.8cm). These differencesexceed the

SEMforhealthyathletesbyfaranddemonstratethatpatientsafter

ACLRperformsignificantlylessontheSLHandTLHwhencompared

toageandsexmatchedathletes.FortheSH,onlysignificant

dif-ferencewerefoundbetweentheinvolvedlimbandthenormative

valuesinmales(P=0.033).

4. Discussion

Themainfindingsofthecurrentstudyhighlightstheneedfora

criticalappraisalofLSIscoresinpatientsafterACLR.Allofpatients

inthecurrentstudyhadameanLSIof95.4%forthe3hoptests,

beingwellovertheclinicalcut-offof90%symmetryfrequentlyused

forRTScriteria[5].DespiteachievingaLSI>90%,patients

demon-strated significant and clinical relevant deficits in performance

for bothlimbswhencompared tonormativedatafromhealthy

Table3

Normativedataforthe3differenthoptests.

Hoptest Study Subjects(n) Outcome SEM(rangecm/hops)

SLH Myersetal.,2014 172 Jumpdistance(cm):males192.0±20.0;females149.0±17.0 4.6–7.9 TLH Jumpdistance(cm):males632.0±72.0;470.0±53.0 15.4–23.2 SH Gustavssonetal.,2006 15 Numberofhops:males55.0±6.0;females41.0±16.0 NR Meanageyears:SD;NR:notreported;range;SLH:singleleghoptest;TLH:tripleleghoptest;SH:sidehop;SEM:standarderrormeasurement.

A.Gokeleretal./Orthopaedics&Traumatology:Surgery&Research103(2017)947–951

Table4

Meandifferences(SD)betweenlimbsinpatientsafterACLreconstructionand betweenpatientsandnormativedatafromhealthyathletesforthe3hoptests.

Males Females SLH(cm)

Differenceinvolvedlimbcomparedto normativedata

35.5±23.5 17.6±13.3

Pvalue <0.001* _<0.001*

Differenceuninvolvedlimbcomparedto normativedata

28.0±23.1 13.0±12.8

Pvalue <0.001* _0.003*

Differenceinvolvedlimbcomparedto uninvolvedlimb

7.4±14.6 4.6±7.7 TLH(cm)

Differenceinvolvedlimbcomparedto normativedata

125.7±71.4 43.5±49.2

Pvalue <0.001* _0.006*

Differenceuninvolvedlimbcomparedto normativedata

104.1±65.6 30.8±49.8

Pvalue <0.001* _0.038*

Differenceinvolvedlimbcomparedto uninvolvedlimb

21.7±42.1 12.7±24.3 SH(numberhops)

Differenceinvolvedlimbcomparedto

normativedata 4.6±12.6 1.4±13.5

Pvalue 0.033* _0.723

Differenceuninvolvedlimbcomparedto normativedata

1.0±12.5 (–)0.9±11.2

Pvalue 0.625 0.770

Differenceinvolvedlimbcomparedto uninvolvedlimb

3.6±8.9 2.3±6.5

Pvalue 0.625 0.770

SLH:singleleghoptest;TLH:tripleleghoptest;SH:sidehoptest;negativevalues representsbetterperformancepatientscomparedtocontrolgroup.

* _{Denotesstatisticalsignificance.}

athletes.Betweenlimbcomparisonrevealedthatthedifferences

betweentheinvolvedanduninvolvedlimbsfortheSLHandTLH

wereallwithintheSEMexceptforfemalesintheTLHwhoexceeded

theSEM.Whencomparedtonormativedata,patientsafterACLR

hadsignificantandclinicallyrelevantshorterjumpdistancesfor

theSLHandfortheTLH.Ourresultsarepartlyinagreementwith

others[6,23].PairotdeFontenayetal.studied13malepatientsat

7.4monthsafterACLR.Thepatientsdemonstratedshorterjump

distancefortheinvolvedlimbcomparedtotheuninvolvedlimb

duringSLHandTLH.Thejumpdistancewas16%shorterforthe

SLHand19%shorterfortheTLHintheuninvolvedlimbin

compar-isontoacontrolgroup[23].Thedifferenceswefound(Table4)are

greaterforwithingroupcomparisonbutevenmorepronounced

whenpatientsafterACLRwerecomparedtohealthyathletes.

Apossibleexplanationforthedecreasedjumpperformancein

patientsafterACLRcomparedtoacontrolgroupcouldbeattributed

tomuscleweaknessassuggestedbysomeauthors[24,25].

How-ever,inarecentsystematicreview,conflictingresultswerefound

forthecorrelationbetweenisokineticstrengthandhoptests[26].

NotonlydopatientsafterACLRexhibitside-to-sidedeficits,butthe

uninvolvedlegafterACLRisalsosignificantlyweakertoamatched

legofacontrolgroup.TheoverallpatternisthattheACLRlegis

weakerthantheuninvolvedleg,whichitselfisweakerthanthat

seeninmatchedhealthycontrols.Thisimpliesthattheuninvolved

legissignificantlyaffectedbytheACLinjury,alsoquestioningto

usetheLSIforstrengthasacriterionforRTS[27].

TheSHassessesdifferentqualitieswhencomparedtotheSLH

andTLH,andisregardedasanendurancetest[22].Thepatients

afterACLRscoredverysimilarnumberofhopsfortheuninvolved

limbcomparedtonormativedata(54.4ACLRversus55.0controls)

[22].FortheSHonlysignificantdifferenceswerefoundfor

com-parisonbetweeninvolvedlimbandthoseofhealthycontrolgroup.

TheSHrequiresincreasedstaminaintheoperativelimb.Thismay

indicatetheprofoundeffectoffatigueintheinvolvedextremityat

the6-monthtimeperiodpost-ACLR[13].

ConsideringthatpatientsafterACLRdemonstrateperformance

deficitscomparedtocontrols,raisesthequestionwhethertheuse

oftheLSIisanappropriatetooltodetectdeficits.Intotal,83%of

ourpatientspassedcriteriasetasLSI>90%fortheSLHand86.8%

respectivelyfortheTLH.Thisisinaccordancewitharecent

sys-tematicreviewof88studiesthatincluded4927patients[13].In

theanalysis,the4standardhoptestsallaveragedgreaterthan90%

LSIat6to9monthspostoperatively[13].Hence,ataperiodintime

afterACLRwhenindeedmostathletesareclearedforRTS[28].The

cut-offscoreof90%LSIforsingleleghoptestsmaybequestioned

foritssoleuseasacriterionforRTSafterACLRasthismaymask

deficits.Hegedusetal.reportedthatcriterionvalidityhasmixed

evidencebasedontheirreviewregardingtheabilityofthestudied

FPTtopredictfunctionaloutcomeorfutureinjury[26].

Thereisapaucityofnormativedataintheliterature.Seiland

co-workersidentifiedindividualpatientprofilesinpatientsafterACLR

thatincludedage,sex,preinjurylevelofsportsandpreviousACL

injury[29].Asystematicidentificationofpatientsubtypeswould

enhanceindividualizedrehabilitationtailoredtopatient’s

individ-ualtolerance,needs,goalsanddemands(typeandlevelofsports).

Moreover,patientprofilesneedtobereportedinmoredetailto

allowforscientificcomparisonbetweenstudies.Futureoutcome

datashouldnotonlybepresentedaccordingtosex,butalso

accord-ingtoage,preinjurylevelofsportsaswellaspreviousACLinjury

[29].

There are several limitations of our study that should be

acknowledged.First,weusedathletesfromvarioussports.

How-everthereported differencesbetweendifferentsports fall well

withinthestandarddeviationsoftheproposednormativevalues,

makingthemclinicallyirrelevant.Moreover,themajorityofmale

patientswereactiveinfootballandwerecomparedtothe

normat-ivedataforhealthyfootballplayers[21].Thesecondlimitationis

thatthereisconflictingevidenceregardingtheconstructvalidity,

criterionvalidityandresponsivenessofhoptests[26].Nonetheless,

theauthorsofthecurrentstudyfeelthattheiruseiswarranted

astheyarefunctionalmaneuvers,simpletoexecuteanddonot

requirespecializedequipment.

5. Conclusion

Thecollectiveevidencefromthisstudyhighlightsthatathletes

whohaveundergoneanACLRdemonstratebilateraldeficitsonhop

testsincomparisontoageandsexmatchednormativedatafor

healthycontrols.UsingtheLSImayunderestimateperformance

deficitsandshouldthereforebeusedwithcautionasacriterionfor

RTSafterACLR.

Disclosureofinterest

Theauthorsdeclarethattheyhavenocompetinginterest.

AppendixA. Supplementarydata

Supplementarydataassociatedwiththisarticlecanbefound,in

theonlineversion,athttp://dx.doi.org/10.1016/j.otsr.2017.02.015.

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