KNEEINJURIES

AhmedALJabri

outlines

•  Relevantanatomy•  History(focused)•  KneeexaminaBon(specialtests)

•  Toxrayornot?•  Specificinjuries(interac0veformat).

ANATOMY/physiology

•  Thekneeisthelargestandmostcomplicatedjointinthebody.

• MoBonatthekneeisacomplexinteracBonofflexion,extension,rotaBon,gliding,androlling.

• modified‐hingediarthrodialsynovialjoint.•  3bones,2meniscus,4mainligaments.•  Greatstabilitymainlydependsontheintegrityoftheligamentousstructures

WhichofthefollowingisFalse?

1.FuncBonally,thekneejointcanbedividedintothreecompartments:patellofemoral,medialBbiofemoral,lateralBbiofemoral.

2.Foundwithinthepoplitealspacearethepoplitealartery,thepoplitealvein,andtheperonealandBbialnerves.

3.Thelateralandmedialfemoralepicondylesserveasimportantsitesoforiginforthemedialandlateralcollateralligaments,respecBvely

4.1&25.Noneoftheabove

WhichofthefollowingisFalse?

1.FuncBonally,thekneejointcanbedividedintothreecompartments:patellofemoral,medialBbiofemoral,lateralBbiofemoral.

2.Foundwithinthepoplitealspacearethepoplitealartery,thepoplitealvein,andtheperonealandBbialnerves.

3.Thelateralandmedialfemoralepicondylesserveasimportantsitesoforiginforthemedialandlateralcollateralligaments,respec0vely

4.1&25.Noneoftheabove

Regardingpoplitealartery?

•  representsthedirectconBnuaBonofthefemoralarterybeyondtheadductorhiatus

•  descendsacrosstheposterioraspectofthekneejointandterminatesattheleveloftheBbialtubercle.

•  itdividesintotheanteriorandposteriorBbialarteriesattheleveloftheBbialtubercle

•  Itisanchoredfirmlyattheproximalanddistalendsofthepoplitealfossa.

•  Bloodsupplytothekneejointcomesfromthepoplitealarteryviathegeniculatearteries

•  Alloftheabove

Regardingpoplitealartery?

•  representsthedirectconBnuaBonofthefemoralarterybeyondtheadductorhiatus

•  descendsacrosstheposterioraspectofthekneejointandterminatesattheleveloftheBbialtubercle.

•  itdividesintotheanteriorandposteriorBbialarteriesattheleveloftheBbialtubercle

•  Itisanchoredfirmlyattheproximalanddistalendsofthepoplitealfossa.

•  Bloodsupplytothekneejointcomesfromthepoplitealarteryviathegeniculatearteries

•  Alloftheabove

HISTRORY

IniBalAssessment:History

•  Injuryhistory•  Pain•  Clicking•  Locking•  Givingway•  Instability•  Swelling

Injuryhistory

•  High‐energytraumawithoutkneeswellingshouldraisethesuspicionofdisrupBonofthejointcapsulewithexpulsionofjointfluidandhemorrhageintothethighorlowerleg.

•  Lowerenergyinjuriesaremorecommonlyassociatedwithmeniscaltears,patelladislocaBons,andlesssevereligamentinjuries.

•  acBviBeswithtwisBngandturningareassociatedwithanteriorcruciatetearsandmeniscalpathology.

FocusedHistoryQuesBons

• OnsetofPain– Dateofinjuryorwhensymptomsstarted

•  Loca0onofpain– Anterior– Medial

– Lateral– Posterior

FocusedHistoryQuesBons2

• MechanismofInjury‐helpspredictinjuredstructure

–  Contactornoncontactinjury?•  Ifcontact,whatpartofthekneewascontacted?

–  Anteriorblow?–  Valgusforce?–  Varusforce?

– Wasfootofaffectedkneeplantedontheground?

Valgusalignment=distalsegmentdeviateslateralwithrespecttoproximalsegment.

FocusedHistoryQuesBons

•  Injury‐AssociatedEvents– Popheardorfelt?

– Swellingacerinjury(immediatevsdelayed)

– Catching/Locking

– Buckling/Instability(“givingway”)

HistoricalCluestoKneeInjuryDiagnoses

Noncontact injury with “pop” ACL tear Contact injury with “pop” MCL or LCL tear, meniscus

tear, fracture Acute swelling ACL tear, PCL tear, fracture,

knee dislocation, patellar dislocation

Lateral blow to the knee MCL tear Medial blow to the knee LCL tear Knee “gave out” or “buckled” ACL tear, patellar dislocation Fall onto a flexed knee PCL tear

CommonSymptomsFactor Meniscal Cruciate MCL/

LCL Chronic Instability

Swelling + delayed

+++ early

- absent

++ recurrent

Locking yes no no yes

Clicking yes no no yes

Giving way

yes yes no yes

EXAMINATION• 

1.Outlineareasoftenderness.

2.Notewhetheranyeffusionispresent.

3.CheckforrangeofmoBon,valgusstressat0and30degreesofflexion,andvarusstressat0and30degreesofflexion.

4.Evaluatethepatellarandextensormechanismoftheknee(quadricepsandpatellatendons).

5.PerformLachman's,anteriordrawer,posteriordrawer,andpivotshicteststocheckforanterolateralrotatoryinstabilityandfurtherdelineatepossibleinjurytotheanteriorcruciateligament.

6.PerformmeniscalexaminaBonwithMcMurray'sandApley'stests.

1,quadricepstendiniBs;2,prepatellabursiBs,patellapain;3,reBnacularpainacerpatellasubluxaBon;4,patellatendiniBs;5,fatpadtenderness;6,Osgood‐Schlamerdisease(Bbialtuberclepain);7,meniscuspain;8,collateralligamentpain;9,pesanserinetendiniBsbursiBs

STABILITYTESTING

•  AnteriorDrawerTest.•  Lachman'sTest.

•  PosteriorDrawerTest.• McMurray'sTest.

•  Apley'sTest.•  PivotShi\.•  CollateralLigamentStressTest.

AnteriorDrawerTest

•  TheanteriordrawertestisatestfordisrupBonoftheanteriorcruciateligament(ACL).

•  HOWTODOIT?VIDEOs\kneeinjury.flv

AnteriorDrawerTest

•  AposiBvetestisdefinedastheabilityoftheBbiatomoveforwardrelaBvetothefemurcomparedwiththeotherknee.

•  False‐negaBvefindingsmayoccurfromaneffusionprevenBngkneeflexionto90degrees,hamstringmusclespasmcausedbypain,orinsufficientforceappliedduringperformanceofthetest

•  Afalse‐posiBvetestcanbecausedbyposteriorcruciateligament(PCL)insufficiency,whichallowstheBbiatoslipbackonthefemur,showinganabnormalamountofdisplacementwhenpulledforward

Lachman'sTest

•  currentlythebestclinicaltestfordeterminingtheintegrityoftheACL;

•  RELIABLEwhenthereisanacutehemarthrosis

•  thekneeflexed20to30degreeswithonehandgraspingthethighandstabilizingit.TheBbiaispulledforwardwithananteriorlydirectedforce

VIDEOs\KneeExamLachmanTest.flv

Lachman'sTest:gradesofinstability

1.  1+(0to5mmmoredisplacementthanthenormalside),

2.  2+(5to10mm),

3.  or3+(>10mm).

Lachman'sTest:limitaBons

•  PCLmustbeintactforthetesttobevalid•  false‐negaBvetestsincludehamstringspasm,meniscaltears,andthird‐degreeMCLtearswithposteriormedialextension.

•  SpecificlimitaBonsofLachman'stestincludedifficultyquanBtaBngtheamountofanteriortranslaBonandinabilitytolimitmoBonofthefemur.

•  Lachman'stestalsomaybedifficulmoperformiftheexaminer'shandsaresmallrelaBvetothepaBent'sthigh.

PosteriorDrawerTest

•  Theposteriordrawertestremainsthe“goldstandard”forevaluaBngPCLinjury

•  Howtodoit?VIDEOs\PosteriorDrawerTest‐Knee.flv

PosteriorDrawerTest

PosteriordisplacementoftheBbiamorethan5mm, or a “soc” endpoint, indicates injury tothe PCL. A normal knee should exhibit nosignificantposteriorexcursion

McMurray'sTest

• McMurray'stestisusedtoidenBfymeniscaltears

•  Howtodoit?VIDEOs\McMurraystest.flv

McMurray'sTest

1.  AposiBvetestoccurswhen,withtheotherhand,a“clicking”sensaBonisfeltalongthejointlineorthepaBentexperiencespainduringinternalandexternalrotaBon.

2.  BytwisBngthelegintointernalrotaBon,theposteriorsegmentofthelateralmeniscusistested.

3.  ExternalrotaBonteststheposteriorsegmentofthemedialmeniscus

Apley'sTest

1.  Apley'stestalsoaidsindiagnosingmeniscaltears.

2.  WiththepaBentprone,thekneeisflexed90degrees,andthelegisinternallyandexternallyrotatedwithpressureappliedtotheheel.

3.  DownwardpressureeliciBngpainsuggestsmeniscalpathology.

4.  ThepainshouldberelievedwithdistracBonofthekneeandrotaBonofthelegbacktoaneutralposiBon.

PivotShi\

•  ItshouldbedonecarefullyasitmayexacerbatetheiniBalinjury.

•  UsedtodetectanterolateralrotatoryinstabilityassociatedwithaninjurytotheACLorlateralcapsularstructure.

•  UNCOMFORTABLE,Usuallydonepre‐operaBvely

•  Howtodoit?VIDEOs\Pivotshictest.flv

CollateralLigamentStressTest

ThecollateralligamentstresstestisusedtotesttheintegrityoftheMCLandLCL.

ValgusandvarustesBngatboth0and30degreesofflexion?

ItisimperaBvethattheinjuredkneebestresstestedtodetectligamentousinjury.Whichofthefollowingstatementsdescribing

thestresstestsforthekneeisFALSE?

1.  Lachman'stest:amempttomovetheparBallyflexedBbiaanteriorlyandposteriorlyonthefemur;laxityindicatescruciateinjury.

2.  Applyvarusandvalgusstresswiththekneein20‐30degreesflexion.DetectsmedialorlateralligamentinjuryUNLESSthecruciatesareintact.

3.  Applyvarusandvalgusstressinfullextension.Instabilityindicatesinjurytothecruciatesaswellasthemedialorlateralligaments.

4.  PosteriorsagoftheupperBbiaorposteriordrawersign:ruptureoftheposteriorcruciate.

5.  Anteriordrawersign:ruptureoftheanteriorcruciate.6.  Lateralpivotshic:onehandappliesavalgusforcetotheextendedknee

withthethumbonthefibularheadandtheotherhandinternallyrotatesthefootwhileflexingtheknee.Near30degrees,thelateralBbiawillpalpablyreducewithlateralandanteriorcruciateinstability.

ItisimperaBvethattheinjuredkneebestresstestedtodetectligamentousinjury.Whichofthefollowingstatementsdescribing

thestresstestsforthekneeisFALSE?

Applyvarusandvalgusstresswiththekneein20‐30degreesflexion.DetectsmedialorlateralligamentinjuryUNLESSthecruciatesareintact.

(Inslightflexionthecruciatesareunstressedandvarus/valgusstresscandetectisolatedmedialorlateralligamentinjury.Infullextensionthecruciatesstabilizethekneetovarus/valgusstress)

AllofthephysicalexaminaBonfindingsareconsistentwithameniscuskneeinjuryEXCEPT:

1.  Jointlinetenderness.2.  Kneeorgroinpain,locking,andlimitedexcursionofthe

joint.3.  Effusionthattendstodeveloprapidlyacertheinjury.4.  Apleytest:flextheknee90degreesandcompressand

rotatetheBbiaonthecondyles;painimpliesatornposteriorhornofthemedialmeniscus.

5.  PosiBveMcMurraytest:WiththethumbandfingerspalpaBngthelateralandmedialjointlines,extendthekneewhilerotaBngthefootexternally;repeatwhilerotaBngthefootinternallywiththeoppositehand.Pain,lockingandgrindingaresuggesBveofameniscusinjury.

AllofthephysicalexaminaBonfindingsareconsistentwithameniscuskneeinjuryEXCEPT:

1.  Jointlinetenderness.2.  Kneeorgroinpain,locking,andlimitedexcursionofthe

joint.3.  Effusionthattendstodeveloprapidlya\ertheinjury.4.  Apleytest:flextheknee90degreesandcompressand

rotatetheBbiaonthecondyles;painimpliesatornposteriorhornofthemedialmeniscus.

5.  PosiBveMcMurraytest:WiththethumbandfingerspalpaBngthelateralandmedialjointlines,extendthekneewhilerotaBngthefootexternally;repeatwhilerotaBngthefootinternallywiththeoppositehand.Pain,lockingandgrindingaresuggesBveofameniscusinjury.

RadiographicEvalua0on

toxrayornot

AllofthefollowingarecomponentofOmawaKneeRule,except?

1.  thepaBentis55yearsorolder2.  thereistendernessattheheadofthefibula3.  thereisisolatedtendernessofthepatella4.  thepaBentisunabletoflexthekneeto90º5.  thereiskneeeffusion6.  thepaBentisunabletotakefourstepsboth

attheBmeoftheinjuryandattheBmeoftheevaluaBon

AllofthefollowingarecomponentofOmawaKneeRule,except?

1.  thepaBentis55yearsorolder2.  thereistendernessattheheadofthefibula3.  thereisisolatedtendernessofthepatella4.  thepaBentisunabletoflexthekneeto90º5.  thereiskneeeffusion6.  thepaBentisunabletotakefourstepsboth

attheBmeoftheinjuryandattheBmeoftheevaluaBon

OmawaKneeRule

• Morethan$1billionisspentonemergencyradiographyofthekneeeachyearintheUnitedStates,with90%‐92%ofthesestudiesshowingnofracture.

•  Theruleisalmost100%sensiBveand97%specific.

PimsburghKneeRuleinbluntkneetrauma

statesthatradiographyisnecessaryonlyifthepaBentfellorsustainedblunttraumatotheknee,andeitheroftwocondiBonsispresent:

•  (1)ageyoungerthan12orolderthan50or•  (2)inabilitytowalkfourfullweight‐bearingstepsintheemergencydepartment.

TRUEORFALSE?

•  InTraumaThetradiBonal“kneeseries”isanteroposterior,lateral,andsunriseview.

FALSE

CORRECT:InTraumaThetradiBonal“kneeseries”isanteroposterior,lateral,andtunnelviews

Tunnel”views,whichimagetheintercondylarnotch,areusedtodetectBbialspinefracturesandloosebodieswithinthenotch

Specificinjuries

Kneedisloca0onrequiresimmediateorthopedicconsulta0onduetothehighincidenceof

complica0ons,includingallofthefollowingEXCEPT:

•  unstableligamentinjury• meniscusinjury

•  poplitealarteryinjury•  sciaBcnerveinjury•  Bbialnerveinjury•  peronealnerveinjury

Kneedisloca0onrequiresimmediateorthopedicconsulta0onduetothehighincidenceof

complica0ons,includingallofthefollowingEXCEPT:

•  unstableligamentinjury• meniscusinjury

•  poplitealarteryinjury•  scia0cnerveinjury•  Bbialnerveinjury•  peronealnerveinjury

KNEEDISLOCATION

•  50%‐60%areanterior•  poplitealarteryinjuryismostcommonlyassociatedwithposteriordislocaBons

•  PeronealnerveinjuryisthemostcommonmajorneurologicalproblemassociatedwithkneedislocaBon.

• WHENTOORDERANANGIOGRAPHY?

Bi‐parBtepatella(normalvariant)

Transverseandavulsionfracturesofthepatellaaremostocenduetoexcessivequadricepstensionrupturingthepatella,whereascomminuted

fracturesarecausedbydirecttrauma.Whichofthefollowingstatementsdescribingthetreatmentofpatella

fracturesisFALSE?

1.  nondisplacedtransversefracture:ankletogroincylindercast

2.  transversefracturedisplaced>2‐3mmorlargeavulsion:wirefixaBon

3.  minorcomminuBonwithminimalseparaBon:meBculousalignmentandwirefixaBonofthefragments

4.  comminutedfracture:excisionofbonefragmentsanddirectanastomosisofthequadricepstendontothepatellarligaments

Transverseandavulsionfracturesofthepatellaaremostocenduetoexcessivequadricepstensionrupturingthepatella,whereascomminuted

fracturesarecausedbydirecttrauma.Whichofthefollowingstatementsdescribingthetreatmentofpatella

fracturesisFALSE?

1.  nondisplacedtransversefracture:ankletogroincylindercast

2.  transversefracturedisplaced>2‐3mmorlargeavulsion:wirefixaBon

3.  minorcomminu0onwithminimalsepara0on:me0culousalignmentandwirefixa0onofthefragments

4.  comminutedfracture:excisionofbonefragmentsanddirectanastomosisofthequadricepstendontothepatellarligaments

Segondfracture

•  representsabonyavulsionofthelateralBbialplateau

•  animportantmarkerofACLdisrupBon

TibialPlateauFractures

•  BecausetheiniBalinjuryisusuallyavalgusstresswithanabducBonforceontheleg,55%to70%ofcondylarfracturesinvolvethelateralplateau

•  ThemostimptaspectoftheiniBalexaminaBonistheneurovascstatus

•  DisplacedfracturesofthelateralcondylemayproduceperonealnerveparalysisinaddiBontoinjurytotheanteriorBbialartery

fourfactorsdeterminetheprognosisofBbialplateaufractures:

1.  degreeofarBculardepression,2.  extentandseparaBonofthecondylarfracturelines,3.  diaphyseal‐metaphysealcomminuBonand

dissociaBon,

4.  integrityofthesocBssueenvelope(i.e.,openversusclosed)

Management

• Asarule,accuratereducBonandprolongednon–weightbearingaretheguidelinestobefollowedinBbialcondylarfractures.

• Maintechniques– compressiondressing,closedreducBonandcasBng,skeletaltracBon,andopenreducBonwithinternalfixaBon

•  Ingeneral,withmoreseverelydepressed#s,operaBvetreatmenthasbemerresultsthannonoperaBvetherapy;however,nouniversalagreementexistsontheacceptableamountofarBculardepression

Osteochondri00sDissecans

•  ThedisorderisfoundmainlyinadolescentsandresultsinasegmentofarBcularcarBlageandsubchondralbonebecomingparBallyortotallyseparatedfromtheunderlyingbone

•  ThemanagementofthesepaBentsisbasedonthestabilityoftheosteochondralfragmentandthematurityoftheskeleton–  Iftheepiphysesareopen,conservaBvetreatmentwith

protecBveweightbearingusuallyresultsinhealingofthelesion.– Oncetheepiphysesareclosed,theprognosisforhealingis

guarded.Ifthefragmentsaredetached,theloosefragmentsrequiresurgeryforremovalorfixaBon.ProtectedrangeofmoBonwithnon–weight‐bearingacBvityfor6to10weeksisgenerallyadvised

AboyhasfallenfromalowlimbofatreeorfromhisbicycleontohisrightkneeandfracturedtheanteriorBbialspine

(intercondylareminence)oftheBbia.WhichofthefollowingstatementsconcerninghisinjuryisFALSE?

1.  HisexamwillrevealaposiBvedrawersignandLachman'stest,andpossiblylaxityofthemedialcollateralligamentonvalgusstress.

2.  Hisx‐raywillrevealafractureoftheBbialspine.3.  Usually,surgicaltreatmentwithscreworwire

fixaBonispreferred.4.  Usuallyclosedtreatment(ifposiBoningcan

achieveanatomicreducBon)ispreferred;otherwiseopenorarthroscopicfixaBonmayberequired.

AboyhasfallenfromalowlimbofatreeorfromhisbicycleontohisrightkneeandfracturedtheanteriorBbialspine

(intercondylareminence)oftheBbia.WhichofthefollowingstatementsconcerninghisinjuryisFALSE?

1.  HisexamwillrevealaposiBvedrawersignandLachman'stest,andpossiblylaxityofthemedialcollateralligamentonvalgusstress.

2.  Hisx‐raywillrevealafractureoftheBbialspine.3.  Usually,surgicaltreatmentwithscreworwire

fixa0onispreferred.4.  Usuallyclosedtreatment(ifposiBoningcan

achieveanatomicreducBon)ispreferred;otherwiseopenorarthroscopicfixaBonmayberequired.

SegondfractureandBbialspineavulsionfracture

•  CTimageofkneedemonstraBngSegondfractureandBbialspineavulsionfracture

FractureoftheTibialSpine(intercondylareminence)

•  Thespinehastwoprominences:themedialandlateraltubercles

•  TheACLandtheanteriorhornsofboththemedialandthelateralmenisciamachintheanteriorintercondylarfossa.ThePCLandtheposteriorhornsofthemenisciamachintheposteriorintercondylarfossa.

•  RadiographicevaluaBonshouldincludestandardAPandlateralviews,butatunnelviewprovidesaclearerlookattheintercondylarareaandmaybenecessarytoconfirmthediagnosis

intercondylareminence:CLASSIFICATION

–  TypeIinvolvesincompleteavulsionoftheBbialspinewithoutdisplacement.

–  TypeII,thereisanincompleteavulsionwithminimaldisplacementoftheanteriorthirdofthefracturefragment,buttheposteriorporBonremainsadherent.

–  TypeIIIischaracterizedbycompleteseparaBonofthefragmentfromitsfracturebedandhasahigherassociatedrateofcollateralligamentinjuriesandperipheralmeniscaltears

•  TypeIIIA,fractureswithcompletedisplacement,

•  TypeIIIB,fractureswithdisplacementandrotaBon

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