Rev. Bras. Reumatol. vol.57 número1

w w w . r e u m a t o l o g i a . c o m . b r

REVISTA

BRASILEIRA

DE

REUMATOLOGIA

Original

article

Secondary

hyperalgesia

occurs

regardless

of

unilateral

or

bilateral

knee

osteoarthritis

involvement

in

individuals

with

mild

or

moderate

level

Vanessa

Martins

Pereira

Silva

Moreira

,

Saulo

Delfino

Barboza

,

Juliana

Borges

Oliveira

_,

_Janser

_Moura

_Pereira

_,

_Valdeci

_Carlos

_Dionisio

a_{UniversidadeFederaldeUberlândia(UFU),FaculdadedeMedicina,ProgramadeMestradoemCiênciasdaSaúde,Uberlândia,MG,}

Brazil

b_{UniversidadeFederaldeUberlândia(UFU),FaculdadedeEducac¸ãoFísica,Uberlândia,MG,Brazil} c_{UniversidadeFederaldeUberlândia(UFU),FaculdadedeMatemática,Uberlândia,MG,Brazil}

a

r

t

i

c

l

e

i

n

f

o

Articlehistory:

Received12October2015 Accepted6February2016 Availableonline13April2016

Keywords:

Kneeosteoarthritis Pain

Pressurepainthreshold Secondaryhyperalgesia

a

b

s

t

r

a

c

t

Background:Secondary hyperalgesia in individuals with less severe levels of knee osteoarthritisremainsunclear.Theobjectiveofthisstudywastomeasurethepressure painthresholdofindividualswithmildormoderatekneeosteoarthritisandcomparewith noosteoarthritis.

Methods:Tenhealthycontrolsand30individualswithmildormoderatekneeosteoarthritis dividedintotwogroups(unilateralandbilateralinvolvement)wereincluded.Dermatomes inlumbarlevels(L1,L2,L3,L4andL5)andsacrallevel(S1andS2),myotomes(vastus medi-alis, vastuslateralis,rectusfemoris,adductor longus,tibialisanterior,peroneuslongus, iliacus,quadratuslumborum,andpopliteusmuscles),andsclerotomesinlumbarlevels (L1-L2,L2-L3,L3-L4,L4-L5supraspinousligaments),overtheL5-S1andS1-S2sacralareas, pesanserinusbursae,andatthepatellartendonpressurepainthresholdwereassessedand comparedbetweenindividualswithandwithoutkneeosteoarthritis.

Results:Kneeosteoarthritisgroups(unilateralandbilateral)reportedlowerpressurepain thresholdcomparedtothecontrolgroupinmostareas(dermatomes,myotomes,and scle-rotomes).Therewerenobetweengroupdifferencesinthesupra-spinousligamentsandover theL5-S1andS1-S2sacralareasofthesclerotomes.Nodifferencewasseenbetweenknee osteoarthritis.

Conclusion: Thesefindingssuggestthatindividualswithmildtomoderateknee osteoarthri-tis had primary and secondary hyperalgesia, independent of unilateral or bilateral involvement.Theseresultssuggestthatthepainhavetobeanassertivefocusintheclinical practice,independentofthelevelofseverityorinvolvementofkneeosteoarthritis.

©2016ElsevierEditoraLtda.ThisisanopenaccessarticleundertheCCBY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).

∗ _{Correspondingauthor.}

E-mail:vanessamartinsfisio@gmail.com(V.M.PereiraSilvaMoreira). http://dx.doi.org/10.1016/j.rbre.2016.03.014

A

hiperalgesia

secundária

ocorre

independentemente

do

envolvimento

unilateral

ou

bilateral

da

osteoartrite

de

joelho

em

indivíduos

com

doenc¸a

leve

ou

moderada

Palavras-chave: Osteoartritedejoelho Dor

Limiardedoràpressão Hiperalgesiasecundária

r

e

s

u

m

o

Introduc¸ão: Aocorrênciadehiperalgesiasecundáriaemindivíduoscomníveismenosgraves de osteoartritede joelhoaindaéincerta.Oobjetivodesteestudofoimedirolimiarde doràpressãodeindivíduoscomosteoartritedejoelholeveoumoderadaecompararcom indivíduossemosteoartrite.

Métodos: Foramincluídos10controlessaudáveise30indivíduoscomosteoartritedejoelho leveoumoderada,divididosemdoisgrupos(envolvimentounilateralebilateral).Foi avali-adoecomparadoolimiardedoràpressãoemdermátomosnosníveislombares(L1,L2, L3,L4,L5)eníveissacrais(S1eS2),miótomos(músculosvastomedial,vastolateral,reto femoral,adutorlongo,tibialanterior,fibularlongo,ilíaco,quadradodolomboepoplíteo) eesclerótomosnosníveislombares(ligamentossupraespinaisL1-L2,L2-L3,L3-L4,L4-L5), sobreasáreassacraisL5-S1eS1-S2,bolsaanserinaetendãopatelarentreosindivíduos comesemosteoartritedejoelho.

Resultados: Osgrupososteoartritedejoelho(unilateralebilateral)relatarammenorlimiar dedoràpressãoemcomparac¸ãocomogrupocontrolenamaiorpartedasáreas (dermá-tomos,miótomoseesclerótomos).Nãohouvediferenc¸asentreosgruposnosligamentos supraespinaiseaolongodasáreassacraisL5-S1eS1-S2dosesclerótomos.Nãofoiobservada qualquerdiferenc¸aentreosindivíduoscomosteoartritedejoelho.

Conclusão: Essesachadossugeremqueosindivíduoscomosteoartritedejoelholevea mod-eradatinhamhiperalgesiaprimáriaesecundária,independentementedoacometimento unilateraloubilateral.Essesresultadossugeremqueadorprecisaserumfocoassertivona práticaclínica,independentementedograudegravidadeouenvolvimentodaosteoartrite dejoelho.

©2016ElsevierEditoraLtda.Este ´eumartigoOpenAccesssobumalicenc¸aCC BY-NC-ND(http://creativecommons.org/licenses/by-nc-nd/4.0/).

Introduction

Thekneeisthemostcommonjointaffectedby osteoarthri-tis, and the prevalence increases with aging.1 _{Pain is the}

mainsymptomofkneeosteoarthritis(KOA),anditspresence andseverityareimportantdeterminantsofdecreased func-tionalcapacity.2,3 _{Primaryhyperalgesiahasbeendefinedas}

increasedactivityofprimaryafferentnociceptorsatthesite ofadeterminedinjuredtissue,whilesecondaryhyperalgesia isdefinedaspresenceofpain inareasbeyondtheoriginal injuredarea.4_{Primaryandsecondaryhyperalgesiamayoccur}

inKOAand resultinmodulation ofnociceptorsand spinal hornneurons,respectively.5

Thepressure pain threshold (PPT) has been considered

the most reliable parameter to classify inflammation in

osteoarthritis,6,7 _{and hasbeen usedtodetect the presence}

ofsecondary hyperalgesia indermatomes, myotomes, and

sclerotomes.2,5 _{PPTseems tohavedifferent levels between}

individualswithandwithoutosteoarthritis,2,8_however,

cur-rent evidence does not answer if PPT levels are different betweenthe different severities(e.g., mildor moderate) of KOA.2,9,10_{Inthepast,Gerecz-Simonetal.}11_evaluated

individ-ualswithkneeOA,butjustpainwasmildandmoderate.Also, theyusedonlytwopointsinlowerlimb.Recently,ithasbeen

demonstrated that individuals withmoderate KOA present

localizedpainandnotcontralateralhyperalgesia,12_however,

in this study, although not mentioned, the characteristics

ofthe participantssuggests that individualshad unilateral KOA.Therefore,assessingPPTinmultiplespointsmightbring meaningfulinformationaboutthepain,aswellascontribute to clinical approach. As joint damage occurs gradually in osteoarthritis (i.e., with progressive function loss oftissue stabilizers),13 _{secondary hyperalgesiawould beexpectedto}

occurinthedevelopmentprocessofosteoarthritis,and uni-lateral orbilateral involvementmightplayaroleon this,14

resultingindifferentpainfulpoints.Thus,thisstudyaimed tomeasurethePPTlevelsinmildormoderateKOA individ-ualswithunilateralandbilateralinvolvementandcompareto individualswithoutKOA.Wehypothesizedthatsomelevelof secondaryhyperalgesiawouldbepresentinindividualswith mildandmoderateKOAandwouldbeeffectofunilateralor bilateralinvolvement.

Materials

and

methods

Participants

Table1–Characteristicsofkneeosteoarthritis(KOA)andhealthycontrolindividuals.

Individuals Age

(mean±SD)

Gender I/MIknee SeverityKOA Medications

Control (n=10)

57.8±6.22 Females

(n=6)

– – –

Males (n=4)

– – –

KOA Unilateral (n=15)

59.86±7.61 Females

(n=11)

Rightknee (n=11)

Mild (n=7)

n=8

Males (n=4)

Leftknee (n=4)

Moderate (n=8)

Bilateral (n=15)

64±10.06 Females

(n=7)

Rightknee (n=9)

Mild (n=4)

n=7

Males (n=8)

Leftknee (n=6)

Moderate (n=11)

SD,standarddeviation;I,involvedkneeinunilateralKOA;MI,moreinvolvedkneeinbilateralKOA.

Forinclusion,individualsshouldbe50-years-oldormore, have diagnosed KOA in the evaluation (unilateral or bilat-eral),andpainforatleast6months.Thediagnosis ofKOA wasbased onthe classificationoftheAmerican Collegeof Rheumatology,15 _{accompanied by radiological evidence of}

osteoarthritisaffectingoneormorecompartments,according totheradiologicalcriteriaofKellgrenandLawrence.16

Indi-vidualswereexcludediftheyhadanyofthefollowing:other musculoskeletaldisorders;chronicdiffusepain(fibromyalgia),

chronicinflammatoryconditions, suchasautoimmune

dis-eases(rheumatoid arthritis,lupus, gout);diabetes mellitus; neuromusculardisorders,suchasParkinson’sdisease;vertigo orotherconditionsthatcouldaffectthesensorycapabilities andcontrolofmovement.Individualswhousedcentral con-trolofpainmedications,suchasantidepressantsalsowere excluded, but individuals who usedoralnonsteroidal anti-inflammatorydrugs,itwasallowedtocontinueitsuse.

Afterselection,30individualswithKOAwereincluded.Ten individualsolderthan50yearswhohadnohistoryofinjury, surgery,andpaininthe lowerextremitieswereselectedby conveniencetocomposethecontrolgroup.Allincluded par-ticipantssignedtheinformedparticipationconsent,andwere dividedintothreegroups:bilateralKOA(n=15),unilateralKOA (n=15)and control (n=10). Table 1shows the participants’ characteristics.

Painassessment

Adigitalforcegauge(ForceTENTM_{FDX,WagnerInstruments,}

Greenwich,CT,USA)and withaflat

½

wereusedformechanicalquantificationofhyperalgesiaand allodyniaresultingfromperipheralorcentralnociceptive sen-sitization.Themeasurementswereperformedbilaterallyin thedermatomesatlevelsL1,L2,L3,L4,L5,S1andS2,using thepinch and rollmaneuverdescribed byImamura et al.5

Thesame wastaken formyotomes, atnine predetermined

locations (vastus medialis, vastus lateralis, rectus femoris, adductorlongus, tibialisanterior, peroneus longus,iliacus,

quadratus lumborum, and popliteus muscles). Finally, the

sclerotomeswereevaluatedintheL1–L2,L2–L3,L3–L4,L4–L5

supraspinous ligaments, over the L5–S1 and S1–S2 sacral

areas,pesanserinusbursae,andatthepatellartendon(Fig.1). Twoexperiencedresearcherscollectedallthedata,usingstrict criteriaforthelocationofthepoints.ThePPTwasexpressed inkg/cm2_{,withthehighestvaluesdenotinglesssevere}

symp-toms.

Statisticalanalysis

Inmanysituationsitisnecessarytocheckwhetherthereisa significantdifferenceinmeantreatmentk(k>2).Onesolution wouldbetheFtestthroughtheanalysisofvariance(ANOVA), whichallowsustojointlytestthemeansofktreatments. How-ever, insomesituations themodel assumptions(normality andhomogeneityindependenceofresiduals)arenotsatisfied.

Therefore we recommendthe use ofnon-parametric tests,

i.e.,anon-parametricinference.Inthisworkweappliedthe

Kruskal–Wallis test consisting ofa non-parametric ANOVA

because the assumptions of parametric ANOVA were not

met.17

Results

Significant difference in the mean values of the PPT was

foundbetweencontrolandKOAunilateralandbilateralgroups (p<0.03), whileno differencewas foundbetweenKOA

uni-lateral and bilateral groups. The KOA groups had a lower

pain thresholdinmostareas ofthe dermatomes (Table2), myotomes(Table3),andsclerotomes(onlythepesanserinus bursaeandpatellartendon;Table4).However,therewasno differenceinthemeanvaluesofthePPT(p>0.05)inthe scle-rotomes ofthesupraspinous ligaments,overthe L5-S1and S1-S2sacralareas(Table4).

Discussion

TheaimofthisstudywastomeasurethePPTofindividuals withmild and moderateKOA (withunilateraland bilateral

involvement) and compare with those without KOA. The

10

9

12

12

12

12

11

12

12

4

2

3

7

8

5

₆

1

Fig.1–Theanatomicsitesusedintheevaluationofthepressurepainthreshold(PPT)ofthemuscles,patellartendon,and pesanserinusbusaeintheanterior,posterior,andlateralviews.(1)Vastusmedialismuscle;(2)rectusfemorismuscle;(3) vastuslateralismuscle;(4)adductorlongusmuscle;(5)anteriortibialismuscle;(6)peroneuslongusmuscle;(7)patellar tendon;(8)pesanserinusbursae;(9)poplitealmuscle;(10)iliacmuscle;(11)quadratuslumborummuscle;(12)supraspinous ligamentsandsacralareasbetweenL5-S1andS1-S2.FigureadaptedfromImamuraetal.5

no difference occurred between unilateralor bilateral KOA involvement.

AccordingCourtneyetal.,18_{primaryhyperalgesiaseemsto}

bebasedonsensitizationofperipheralC-fibernociceptorsof deepsomatictissueswhenastimulusisappliedatthelocation oftheinflammation.Thisprocessprogressesifthe nocicep-tivestimulationpersists.Insuchcases,thenerveendingsof

the centralnervous system may bealtered because ofthe

increaseinthereceptivefield,makingthemmoresensitive tostimuli.5_{Theincreaseinsynapticexcitabilityincreasesthe}

responsetobothnoxiousand non-noxiousstimuli,leading toallodyniaandsecondaryhyperalgesia.Insecondary hyper-algesia,astimulusoutofthelesionareacausespaininthe individual.18

AlthoughtheprocessofdegenerationinKOAisnotclear, theresults ofthis study revealed thatthe individuals with

mild to moderate KOA had primary and secondary

hyper-algesia,whereasthehealthycontrolsdidnot.Comparingthe data from this study with those of Imamura et al.,5 _{it is}

suggestedthatwhenKOAprogresses,secondaryhyperalgesia alsoincreases.Imamuraetal.5_{alsoreportedthepresenceof}

secondaryhyperalgesiaindistantregionsoftheknee, includ-ingthelumbarregion,insevereKOAindividuals.Incontrast, inthepresentstudy,theindividualswithmildtomoderate

KOA showedno alterationsinthe lumbarregion.However,

therewerechangesinthepainthresholdofdistantpartsofthe kneethatexhibitedsecondaryhyperalgesia(Tables2and3). Therefore, our results suggest the secondary hyperalgesia wouldoccuralongthedegenerationprocessandwouldnotbe afeaturepresentonlyintheseverelevelofKOA.Similarresults wereshowedbyRakeletal.,12_{however,thePPTpointswere}

onlyinonepointeachprimaryandsecondaryhyperalgesia, andthewaytodeterminateofthemildKOAwasconsidereda limitationofthestudybyauthors.Thepresentstudyusedthe classificationoftheAmericanCollegeofRheumatology,15_and

therefore,itconfirmstheresultsofRakeletal.,12_addingthe

Table2–ResultsKruskal–Wallistestforpressurepainthresholdondermatomes.

Dermatomal 2a p-Value Groups Meanoftheranksb,c

L1 18.7044 0.0022

Control Right_Leftkneeknee 61.55_57.85 a_a

Unilateral Involved_Noninvolvedknee_knee 34.97_34.97 b_b

Bilateral More_Lessinvolvedinvolved_kneeknee 35.00_31.40 b_b

L2 13.9418 0.0159

Control Right_Leftkneeknee 58.05_55.70 a_a

Unilateral Involved_Noninvolvedknee_knee 31.97_34.33 b_b

Bilateral More_Lessinvolvedinvolved_kneeknee 35.20_38.67 b_b

L3 23.2273 0.0003

Control Rightknee 61.70 a

Leftknee 62.20 a

Unilateral Involved_Noninvolvedknee_knee 33.87_34.23 b_b

Bilateral More_Lessinvolvedinvolved_kneeknee 35.47_29.83 b_b

L4 22.0370 0.0005

Control Rightknee 62.15 a

Leftknee 59.8 a

Unilateral Involvedknee 31.67 b

Noninvolvedknee 39.20 b

Bilateral More_Lessinvolvedinvolved_kneeknee 30.30_33.53 b_b

L5 19.7702 0.0014

Control Rightknee 59.60 a

Leftknee 61.15 a

Unilateral Involvedknee 32.10 b

Noninvolvedknee 35.70 b

Bilateral Moreinvolvedknee 34.83 b

Lessinvolvedknee 32.87 b

S1 22.3136 0.0005

Control Rightknee 60.60 a

Leftknee 61.50 a

Unilateral Involvedknee 33.63 b

Noninvolvedknee 35.90 b

Bilateral Moreinvolvedknee 27.77 b

Lessinvolvedknee 37.30 b

S2 14.9281 0.0107

Control Right_Leftkneeknee 58.45_57.25 a_a

Unilateral Involvedknee 33.73 b

Noninvolvedknee 34.73 b

Bilateral Moreinvolvedknee 34.73 b

Lessinvolvedknee 35.00 b

a 2_{statisticalvaluewithone-tailedprobability˛.}

b _{ThemeanranksderivethemeansofPPTcollectedandwasrepresentedbylowercaseletters.}

c _{Differentlowercaselettersinthecolumn,themeansoftheranksofthePPTdifferbyKruskal–Wallistestat5%significancelevel.}

Hassanet al.3 _{noted thatdrugs could acton peripheral}

and/or central pain mechanisms. However, in the present

study,partoftheparticipants(n=15;Table1)wereusing,but thisseemstonotinterfereinPPT,sincemostofthePPTpoints

were more sensitive compared with control group. These

resultsreinforcetheevidencethatdrugsusuallyhavelimited actioninchronicpain,andunsatisfactoryinpainrelief.19

Tay-loretal.20 _{reportedthatbothphysiciansandpatients(51%}

ofrespondents)areunhappywiththeinadequatecontrolof KOAprovidedbytraditionalanti-inflammatorynon-steroidal therapy.Their studyincluded patientswithmild(31%)and moderateorsevereKOA(60%).Inaddition,theseresults sug-gestthatforsecondaryhyperalgesiatreatmentandcontrolof

paininKOA,centralpaindrugscouldbeuseful,sinceNSAIDs actonlyonperipheralpainmechanisms.21

Riddle and Stratford14 _{found pain influence about the}

sideofinvolvement(unilateralorbilateral)measuredby self-report,but ourresultsshowedthatpainnotinfluencedthe sideofinvolvementandnotsupportedtheresultsofthe Rid-dle andStratford.14 _{Despite ofimportantdifferenceofsize}

samplebetweenthesestudies,weshouldconsideratethatan objectivemechanismofpainmensuration(PPT)couldbe dif-ferentoftheself-reportmeasure.RiddleandStratford14_also

Table3–ResultsKruskal–Wallistestforpressurepainthresholdonmyotomes.

Myotomal 2a p-Value Groups Meanoftheranksb,c

ILIO 12.1881 0.0323

Control Right_Leftkneeknee 55.10_56.20 a_a

Unilateral Involved_Noninvolvedknee_knee 38.37_31.00 b_b

Bilateral More_Lessinvolvedinvolved_kneeknee 35.63_36.80 b_b

AL 17.8989 0.0031

Control Rightknee 62.95 a

Leftknee 55.10 a

Unilateral Involved_Noninvolvedknee_knee 32.90_32.47 b_b

Bilateral More_Lessinvolvedinvolved_kneeknee 34.83_37.10 b_b

RF 24.3074 0.0002

Control Rightknee 64.00 a

Leftknee 61.10 a

Unilateral Involvedknee 32.83 b

Noninvolvedknee 31.00 b

Bilateral More_Lessinvolvedinvolved_kneeknee 34.53_34.23 b_b

VM 21.1307 0.0008

Control Rightknee 59.15 a

Leftknee 62.55 a

Unilateral Involvedknee 31.03 b

Noninvolvedknee 34.03 b

Bilateral Moreinvolvedknee 37.17 b

Lessinvolvedknee 32.63 b

VL 18.8512 0.0020

Control Rightknee 62.30 a

Leftknee 57.10 a

Unilateral Involvedknee 35.33 b

Noninvolvedknee 31.20 b

Bilateral Moreinvolvedknee 33.73 b

Lessinvolvedknee 36.13 b

TA 24.7054 0.0002

Control Right_Leftkneeknee 61.20_64.20 a_a

Unilateral Involvedknee 34.87 b

Noninvolvedknee 34.37 b

Bilateral Moreinvolvedknee 32.17 b

Lessinvolvedknee 31.00 b

FL 21.5347 0.0006

Control Right_Leftkneeknee 63.10_59.10 a_a

Unilateral Involved_Noninvolvedknee_knee 30.30_34.17 b_b

Bilateral More_Lessinvolvedinvolved_kneeknee 34.87_35.20 b_b

QL 24.6522 0.0002

Control Right_Leftkneeknee 59.35_65.70 a_a

Unilateral Involved_Noninvolvedknee_knee 31.47_33.10 b_b

Bilateral More_Lessinvolvedinvolved_kneeknee 32.17_35.90 b_b

POP 26.3413 <0.000

Control Right_Leftkneeknee 62.35_64.45 a_a

Unilateral Involved_Noninvolvedknee_knee 31.20_34.70 b_b

Bilateral More_Lessinvolvedinvolved_kneeknee 30.77_34.80 b_b

ILIO,iliacusmuscle;AL,adductorlongusmuscle;RF,rectusfemorismuscle;VM,vastusmedialismuscle;VL,vastuslateralismuscle;TA,tibialis anteriormuscle;FL,peroneuslongusmuscle;QL,quadratuslumborummuscle;POP,popliteusmuscle.

a

2statisticalvaluewithone-tailedprobability˛.

b _{ThemeanranksderivethemeansofPPTcollectedandwasrepresentedbylowercaseletters.}

Table4–ResultsKruskal–Wallistestforpressurepainthresholdonsclerotomes.

Sclerotomal 2a p-Value Groups Meanoftheranksb,c

TP 24.5637 0.0002

Control Right_Leftkneeknee 63.60_61.30 a_a

Unilateral Involved_Noninvolvedknee_knee 34.43_33.53 b_b

Bilateral More_Lessinvolvedinvolved_kneeknee 29.00_35.77 b_b

PG 19.6622 0.0014

Control Right_Leftkneeknee 59.80_59.95 a_a

Unilateral Involved_Noninvolvedknee_knee 33.67_39.33 b_b

Bilateral More_Lessinvolvedinvolved_kneeknee 31.77_31.40 b_b

L1-L2 3.9834 0.1364

Control Rightknee 48.00 a

Leftknee 43.20 a

Unilateral Involved_Noninvolvedknee_knee 43.27_39.83 a_a

Bilateral More_Lessinvolvedinvolved_kneeknee 41.63_30.47 a_a

L2-L3 2.3155 0.3142

Control Rightknee 37.22 a

Leftknee –

Unilateral Involvedknee 37.58 a

Noninvolvedknee –

Bilateral More_Lessinvolvedinvolved_kneeknee 45.60_– a

L3-L4 4.4425 0.1085

Control Rightknee 37.62 a

Leftknee –

Unilateral Involvedknee 47.48 a

Noninvolvedknee –

Bilateral Moreinvolvedknee 35.43 a

Lessinvolvedknee –

L4-L5 1.5373 0.4636

Control Rightknee 40.30 a

Leftknee –

Unilateral Involvedknee 36.85 a

Noninvolvedknee –

Bilateral Moreinvolvedknee 44.28 a

Lessinvolvedknee –

L5-S1 3.3315 0.1890

Control Right_Leftkneeknee 47.45_– a

Unilateral Involvedknee 41.10 a

Noninvolvedknee –

Bilateral Moreinvolvedknee 35.27 a

Lessinvolvedknee –

S1-S2 0.3497 0.8396

Control Right_Leftkneeknee 39.30_– a

Unilateral Involved_Noninvolvedknee_knee 39.32_– a

Bilateral More_Lessinvolvedinvolved_kneeknee 42.48_– a

PT,patellatendon;PG,pesanserinusbursae;L1-L2,L1-L2supraspinousligament;L2-L3,L2-L3supraspinousligament;L3-L4,L3-L4supraspinous ligament;L4-L5,L4-L5supraspinousligament;L5-S1,L5-S1sacralarea;S1-S2,S1-S2sacralarea.

a 2_{statisticalvaluewithone-tailedprobability˛.}

b _{ThemeanranksderivethemeansofPPTcollectedandwasrepresentedbylowercaseletters.}

c _{Differentlowercaselettersinthecolumn,themeansoftheranksofthePPTdifferbyKruskal–Wallistestat5%significancelevel.}

withpsychologicalstateaccordingtoWiseetal.,22_whichcould

haveinfluencedtheresultsofRiddleandStratford.14

Finally,inthisstudytworesearchersmadethecollection ofthedataandwedidnotassesstheinter-raterreliability, whatcanbeconsideredalimitationofthestudy,sincethere

couldbeaslightdifferenceinthelocationsoftheanatomical points.However,theywerebothexperiencedandusedstrict criteriaforthelocationofthepoints.AsreportedbyFisher,6

Takingalltogether,individualswithmildtomoderateKOA hadprimaryandsecondaryhyperalgesia,independentof uni-lateralorbilateralinvolvement.Theseresultssuggestthatthe painhavetobeanassertivefocusintheclinicalpractice, inde-pendentofthelevelofseverityorinvolvementofKOA.

Conflicts

of

interest

Theauthorsdeclarenoconflictsofinterest.

Acknowledgments

Weappreciatethecontributionofallstudentsofthe Labora-toryofPhysicalTherapyandNeuromechanicaloftheFaculty ofPhysicalEducation,UniversidadeFederaldeUberlândia,for assistanceintechnicalanddiscussionsaboutit.

WethanktheFundac¸ãodeAmparoaPesquisadoEstado

deMinasGerais(FAPEMIG)fortheirsupportofresearch(Grant

APQ-01110-10) and the Conselho Nacional de

Desenvolvi-mentoCientíficoeTecnológico(CNPq)forscholarshiptothis research.

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