Knee Structure & Disorders. Outline Structure Skeletal Soft tissue Ligaments Menisci Bursae ...

KneeKneeStructure & DisordersStructure & Disorders

OutlineOutline

StructureStructure SkeletalSkeletal Soft tissueSoft tissue

LigamentsLigaments MenisciMenisci BursaeBursae

MusclesMuscles MovementMovement

ExamExam DisordersDisorders Aspiraton/injectionAspiraton/injection

Knee: StructureKnee: Structure

Complex diarthrodial jointComplex diarthrodial joint Highly modified hinge jointHighly modified hinge joint CompartmentsCompartments

Medial tibiofemoralMedial tibiofemoral Lateral tibiofemoralLateral tibiofemoral PatellofemoralPatellofemoral

Knee: StructureKnee: StructureSkeletalSkeletal Distal femurDistal femur

Medial condyleMedial condyle Lateral condyleLateral condyle Intercondylar notchIntercondylar notch

Proximal tibial plateauProximal tibial plateau Medial condyleMedial condyle Lateral condyleLateral condyle Intercondylar eminenceIntercondylar eminence

Hyaline Cartilage

Knee: StructureKnee: StructureSkeletalSkeletal

PatellaPatella Largest sesamoid bone in the bodyLargest sesamoid bone in the body Articulates with the trochlea of the distal Articulates with the trochlea of the distal

femurfemur Only engages the femur when knee flexed > Only engages the femur when knee flexed >

3030°° Enhances active extensionEnhances active extension Subject to magnified contact forces 8x body Subject to magnified contact forces 8x body

weightweight Patellar articular cartilage is the thickest in Patellar articular cartilage is the thickest in

the body – up to 7mm!the body – up to 7mm!

Knee: StructureKnee: StructureStabilizersStabilizers

LigamentsLigaments MenisciMenisci BursaeBursae MusclesMuscles Joint capsuleJoint capsule

Knee: StructureKnee: StructureLigamentsLigaments

Medial collateral Medial collateral ligament (MCL)ligament (MCL) Superficial & deepSuperficial & deep Medial epicondyle of Medial epicondyle of

the femur the femur 10cm 10cm below joint linebelow joint line

Resists Resists valgusvalgus stress stress across the kneeacross the knee

Provides secondary Provides secondary rotational stabilityrotational stability


Lateral collateral Lateral collateral ligament (LCL)ligament (LCL) Lateral femoral Lateral femoral

condyle condyle posterior posterior fibular headfibular head

Primary restraint to Primary restraint to varusvarus knee stressesknee stresses


Anterior cruciate Anterior cruciate ligament (ACL)ligament (ACL) Anteromedial bundleAnteromedial bundle

Taut in knee flexionTaut in knee flexion

Posterolateral bundlePosterolateral bundle Taut in knee extensionTaut in knee extension

Resists excessive Resists excessive anterior translationanterior translation and and internal rotationinternal rotation of the tibia relative to of the tibia relative to the femurthe femur


Posterior cruciate Posterior cruciate ligament (PCL)ligament (PCL) Anterolateral bundleAnterolateral bundle

Taut in knee flexionTaut in knee flexion

Posteromedial bundlePosteromedial bundle Taut in knee extensionTaut in knee extension

Prevents excessive Prevents excessive posterior translation posterior translation of the tibiaof the tibia

Knee: StructureKnee: StructurePosterolateral (PLC)Posterolateral (PLC)

Area of major Area of major instabilityinstability

PreventPrevent Excessive Excessive

external rotationexternal rotation Varus angulationVarus angulation Posterior Posterior

translation of the translation of the tibiatibia

Knee: StructureKnee: StructureMenisciMenisci

Crescentic disks Crescentic disks of fibrocartilageof fibrocartilage

Deepen/stabilize Deepen/stabilize the tibiofemoral the tibiofemoral articulationsarticulations

Distribute the Distribute the weight bearing weight bearing loadload


““red zone”red zone” Peripheral thirdPeripheral third VascularizedVascularized Potential to healPotential to heal

““white zone”white zone” Central thirdCentral third AvascularAvascular Minimal healingMinimal healing

““red/white zone”red/white zone” Limited healingLimited healing


Lateral meniscusLateral meniscus Nearly circularNearly circular Loose peripheral Loose peripheral

attachmentsattachments Greater motion in Greater motion in

specific movementsspecific movements Medial meniscusMedial meniscus

Semi-circularSemi-circular Close attachments Close attachments

to bone, medial joint to bone, medial joint capsule, and MCLcapsule, and MCL

Knee: StructureKnee: StructureBursaeBursae

Knee: StructureKnee: StructureMusclesMuscles

Quadriceps - Quadriceps - extensorsextensors Rectus femorisRectus femoris Vastus medialisVastus medialis Vastus lateralisVastus lateralis Vastus intermediusVastus intermedius

Medial and lateral Medial and lateral patellar retinaculapatellar retinacula

Vastus medialis Vastus medialis obliquus – obliquus – restrains restrains lateral patellar lateral patellar subluxationsubluxation

Knee: StructureKnee: StructureMusclesMuscles

Hamstrings – Hamstrings – flexorsflexors Medial Medial

SemimembranosusSemimembranosus SemitendinosusSemitendinosus

LateralLateral Biceps femorisBiceps femoris

Knee: StructureKnee: StructureMusclesMuscles Iliotibial (IT) bandIliotibial (IT) band

Stabilize the lateral side of Stabilize the lateral side of the kneethe knee

Accessory Accessory extensorextensor or or flexorflexor of the knee of the knee

Pes anserinusPes anserinus Gracilis, sartorius, Gracilis, sartorius,

semitendinosussemitendinosus Weak knee Weak knee flexorsflexors Internal rotatorsInternal rotators

Patellar tendonPatellar tendon

Knee: StructureKnee: StructureTibiofemoral motionTibiofemoral motion

Transfer and dissipates Transfer and dissipates weight-bearing loadweight-bearing load Mid-point of weight-bearing axisMid-point of weight-bearing axis

MovementMovement Flexion & extensionFlexion & extension

Arc from 0-135Arc from 0-135°°

Secondary movementSecondary movement ““Roll-back”Roll-back” RotationRotation

Knee: StructureKnee: StructurePatellofemoral motionPatellofemoral motion Augment moment Augment moment

arm of the arm of the extensorextensor mechanismmechanism

Patellofemoral Patellofemoral “tracking”“tracking”

Q-angleQ-angle Measure of balance of Measure of balance of

medial and lateral medial and lateral forces on the patellaforces on the patella

Knee: StructureKnee: StructurePatellofemoral motionPatellofemoral motion

Q-angleQ-angle Angle between line Angle between line

from ASIS to center of from ASIS to center of patella and another patella and another line from tibial tubercleline from tibial tubercle

NormalNormal Men -- 13Men -- 13°° Women – 18°Women – 18°

Abnormal >20°Abnormal >20°

Knee: ExamKnee: ExamHistoryHistory

Patient demographicsPatient demographics Age**Age**

Pain characteristicsPain characteristics Onset, location**, duration, severity, qualityOnset, location**, duration, severity, quality Mechanical symptomsMechanical symptoms EffusionEffusion Mechanism of injuryMechanism of injury

Back or hip symptomsBack or hip symptoms History of inflammatory arthritis or History of inflammatory arthritis or

crystalline arthropathycrystalline arthropathy

Knee: ExamKnee: ExamObservationObservation

GaitGait Skin changesSkin changes Muscle atrophyMuscle atrophy

QuadricepsQuadriceps VMOVMO

AlignmentAlignment Valgus or varusValgus or varus Normal - 7Normal - 7° of valgus° of valgus

Knee: ExamKnee: ExamPalpationPalpation

BursitisBursitis EffusionEffusion

““ballottement test”ballottement test” 10-15 ml of fluid10-15 ml of fluid

““bulge sign”bulge sign” 8-10 ml of fluid8-10 ml of fluid

Extensor mechanismExtensor mechanism Flex knee to 90Flex knee to 90°° Active extensionActive extension

Other superficial Other superficial structuresstructures

Posterior palpationPosterior palpation Medial and lateral Medial and lateral

joint linejoint line

Knee: ExamKnee: ExamRange of motionRange of motion

Flexion-extension arcFlexion-extension arc 0-1350-135°°

Hyperextension or genu Hyperextension or genu recurvatumrecurvatum Up to 10°Up to 10°

Active vs. passiveActive vs. passive PatellofemoralPatellofemoral

Q angleQ angle ““J-sign”J-sign” CrepitusCrepitus

Knee: ExamKnee: ExamLigamentLigament Anterior DrawerAnterior Drawer

ACL

Knee: ExamKnee: ExamLigamentLigament

Lachman testLachman test Knee flexed to 30Knee flexed to 30°° Physician stabilizes distal femur with Physician stabilizes distal femur with

one handone hand Physician grasps proximal tibial in the Physician grasps proximal tibial in the

other hand and attempts to sublux the other hand and attempts to sublux the tibia anteriorlytibia anteriorly

Positive Lachman = lack of clear end Positive Lachman = lack of clear end pointpoint

High positive predictive valueHigh positive predictive value

ACL


Pivot-shift testPivot-shift test Positive test = palpable clunk in the knee at 30Positive test = palpable clunk in the knee at 30° °

of flexionof flexion

ACL


Posterior sag testPosterior sag test

PCL


Posterior drawer testPosterior drawer test Positive test = anterior tibia displaces posteriorly Positive test = anterior tibia displaces posteriorly

until it is flush with distal femoral condyleuntil it is flush with distal femoral condyle

PCL


Medial and lateral collateral ligamentsMedial and lateral collateral ligaments

LCL MCL


Dial testDial test Knee flexed to 30Knee flexed to 30°° External rotation stressExternal rotation stress Positive = difference of Positive = difference of

>10° laxity>10° laxity Repeat test with knee Repeat test with knee

flexed to 90°flexed to 90° (+) test at 30°(+) test at 30°

Isolated PLC injuryIsolated PLC injury

(+) test at 30° and 90 °(+) test at 30° and 90 ° PCL + PLC disruptionPCL + PLC disruption

PLC

Knee: ExamKnee: ExamMeniscusMeniscus

McMurray testMcMurray test Medial and lateral Medial and lateral

meniscimenisci Positive test = thud or Positive test = thud or

click or reproducible click or reproducible pain pain

Knee: ExamKnee: ExamMeniscusMeniscus

Apley Grind testApley Grind test Positive test = Positive test =

pain or clicking pain or clicking with internal or with internal or external rotationexternal rotation

Knee: ExamKnee: ExamRadiographsRadiographs

Anteroposterior viewAnteroposterior view Lateral viewLateral view Merchant’s viewMerchant’s view

Patellofemoral jointPatellofemoral joint

Notch or tunnel viewNotch or tunnel view Postero-anterior view with knee flexed to 40-50Postero-anterior view with knee flexed to 40-50°° Osteochondritis dissecansOsteochondritis dissecans

Weight bearing viewWeight bearing view OsteoarthritisOsteoarthritis

Knee: DisordersKnee: Disorders

Knee: DisordersKnee: DisordersOsgood-Schlatter diseaseOsgood-Schlatter disease

Traction apophysitis of the Traction apophysitis of the tibial tuberositytibial tuberosity

Boys age 10-14Boys age 10-14 Pain over the tibial tuberosity Pain over the tibial tuberosity

Jumping activitiesJumping activities Resisted extensionResisted extension

Treatment nonoperativeTreatment nonoperative Usually self resolvesUsually self resolves Avoid jumping activitiesAvoid jumping activities

Sinding-Larsen-Johansson Sinding-Larsen-Johansson syndromesyndrome

Knee: DisordersKnee: DisordersOsteochondritis DessicansOsteochondritis Dessicans AVN of bone affecting the AVN of bone affecting the

osteochondral junction of osteochondral junction of the epiphysisthe epiphysis

Boys>>>girlsBoys>>>girls Knee most commonly Knee most commonly

affectedaffected Pain and mechanical Pain and mechanical

symptomssymptoms Wilson’s testWilson’s test

Straightening internally Straightening internally rotated knee from a flexed rotated knee from a flexed positionposition

Knee: DisordersKnee: DisordersOsteochondritis DessicansOsteochondritis Dessicans

RadiographsRadiographs X-rays – tunnel view **X-rays – tunnel view ** CTCT MRIMRI

TreatmentTreatment No treatmentNo treatment Conservative tx – activity Conservative tx – activity

limitation, PTlimitation, PT Operative txOperative tx

Microfracture and abrasionMicrofracture and abrasion Osteochondral allograft/autograft Osteochondral allograft/autograft

transfer (OAT)transfer (OAT) Autologous cartilage implantation Autologous cartilage implantation

(ACI)(ACI)

Knee: DisordersKnee: DisordersPatellofemoral disordersPatellofemoral disorders

Anterior knee painAnterior knee pain Imbalance between medial Imbalance between medial

and lateral forcesand lateral forces High Q-angleHigh Q-angle Atrophy of medial stabilizersAtrophy of medial stabilizers Contracture of lateral Contracture of lateral

structuresstructures

Knee: DisordersKnee: DisordersPatellofemoral disordersPatellofemoral disorders

Apprehension testApprehension test Knee in 20Knee in 20° flexion° flexion Patella manually subluxed Patella manually subluxed

laterally to reproduce laterally to reproduce symptoms of instabilitysymptoms of instability

Patella tilt testPatella tilt test Knee in Knee in 2020° flexion° flexion Lateral margin is flipped upLateral margin is flipped up (+) test – patella cannot be (+) test – patella cannot be

tilted upward past horizontaltilted upward past horizontal

Knee: DisordersKnee: DisordersChondromalacia patellaeChondromalacia patellae Anterior knee painAnterior knee pain 4 stages of severity4 stages of severity

Stage I – softening and Stage I – softening and swelling of articular swelling of articular cartilagecartilage

Stage 2 – deep fissures Stage 2 – deep fissures extending to subchondral extending to subchondral bonebone

Stage 3 – fibrillation of Stage 3 – fibrillation of the articular surfacethe articular surface

Stage 4 – loss of articular Stage 4 – loss of articular cartilage with exposed cartilage with exposed subchondral bonesubchondral bone

Knee: DisordersKnee: DisordersMedial plica syndromeMedial plica syndrome

Medial knee painMedial knee pain Mimic medial meniscal Mimic medial meniscal

teartear

Irritation of the medial Irritation of the medial femoral condylefemoral condyle Repetitive overuseRepetitive overuse

Conservative therapyConservative therapy

Knee: DisordersKnee: DisordersInjuryInjury

Knee: DisordersKnee: DisordersACL injuryACL injury

ExamExam LachmanLachman Anterior drawerAnterior drawer Pivot shiftPivot shift

RadiographsRadiographs Avulsion injuries of Avulsion injuries of

tibial spinestibial spines Segond fractureSegond fracture MRIMRI

TreatmentTreatment Low demand - no Low demand - no

treatmenttreatment Moderate demand – Moderate demand –

PT and knee bracePT and knee brace SurgerySurgery

Knee: DisordersKnee: DisordersPCL InjuryPCL Injury

ExamExam Posterior drawerPosterior drawer Posterior sag signPosterior sag sign

MRI – gold standardMRI – gold standard Nonoperative therapyNonoperative therapy

ImmobilizationImmobilization Protected weight-bearingProtected weight-bearing Quad strengtheningQuad strengthening

Knee: DisordersKnee: DisordersMCL/LCL InjuryMCL/LCL InjuryMCLMCL ExamExam

Acute – swelling, bruising, Acute – swelling, bruising, loss of full extensionloss of full extension

Valgus stress at 0Valgus stress at 0° & 30°° & 30° Conservative therapyConservative therapyLCLLCL Usually ruptures at fibular Usually ruptures at fibular

insertioninsertion ExamExam

Varus stress Varus stress at 0at 0° & 30°° & 30° Peroneal nerve palsyPeroneal nerve palsy

Surgical therapySurgical therapy

Knee: DisordersKnee: DisordersMeniscal InjuriesMeniscal Injuries

Acute injuryAcute injury Twisting on weight-bearing kneeTwisting on weight-bearing knee

Degenerative tearsDegenerative tears ExamExam

Knee effusionKnee effusion Joint line tendernessJoint line tenderness Pain with hyperflexion or hyperextensionPain with hyperflexion or hyperextension McMurray’s testMcMurray’s test Apley grind testApley grind test

Knee: DisordersKnee: DisordersMeniscal InjuriesMeniscal Injuries MRI – study of choiceMRI – study of choice TherapyTherapy

ConservativeConservative NSAIDs, periodic intra-NSAIDs, periodic intra-

articular steroid injectionarticular steroid injection

SurgicalSurgical Arthroscopic Arthroscopic

meniscectomymeniscectomy Arthroscopic repairArthroscopic repair

Knee: DisordersKnee: Disorders

Knee: DisordersKnee: DisordersSynovial chondromatosisSynovial chondromatosis Multiple metaplastic foci of Multiple metaplastic foci of

cartilage develop cartilage develop JointsJoints Tendon sheathsTendon sheaths BursaeBursae

Late teens – middle ageLate teens – middle age Knee pain and swelling with Knee pain and swelling with

mechanical symptomsmechanical symptoms Exam – swollen knee with Exam – swollen knee with

thick synovium, crepitus, thick synovium, crepitus, and palpable loose bodiesand palpable loose bodies

TreatmentTreatment Removal of loose bodiesRemoval of loose bodies Excision of active Excision of active

synoviumsynovium

Knee: DisordersKnee: DisordersPigmented villonodular Pigmented villonodular synovitissynovitis

Uncommon proliferative Uncommon proliferative tumor of synovial tissuetumor of synovial tissue

Episodic pain/swellingEpisodic pain/swelling Recurrent atraumatic knee Recurrent atraumatic knee

hemarthrosis ** hemarthrosis ** Exam – tender swollen jointExam – tender swollen joint MRI – mainstay with MRI – mainstay with

characterstic findingscharacterstic findings TreatmentTreatment

Arthroscopic debridementArthroscopic debridement Open synovectomyOpen synovectomy

Knee: DisordersKnee: DisordersAspiration/InjectionAspiration/Injection Medial approachMedial approach

Push patella laterallyPush patella laterally Superior 1/3 of patellaSuperior 1/3 of patella

Lateral approachLateral approach ComplicationsComplications

PainPain InfectionInfection Post-injection flarePost-injection flare Joint instability from repeat Joint instability from repeat

injectionsinjections Recurrent effusion or painRecurrent effusion or pain

QUESTIONSQUESTIONS

ReferencesReferences

Calmbach and Hutchens. Calmbach and Hutchens. Am Fam PhysicianAm Fam Physician. . 2003;68:907-912.2003;68:907-912.

Calmbach and Hutchens. Calmbach and Hutchens. Am Fam PhysicianAm Fam Physician. . 2003;68:917-922.2003;68:917-922.

Cardone and Tallia. Cardone and Tallia. Am Fam PhysicianAm Fam Physician. 2003;67:2147-. 2003;67:2147-52.52.

Hochberg et al. Hochberg et al. Rheumatology 4Rheumatology 4thth Edition Edition. 2008.. 2008. Jackson and O’Malley. Jackson and O’Malley. Ann Intern MedAnn Intern Med. 2003;139:575-. 2003;139:575-

588.588. Lubowitz et al. Lubowitz et al. Am J Sports MedAm J Sports Med. 2008;36:577-594.. 2008;36:577-594. Zuber. Zuber. Am Fam PhysicianAm Fam Physician. 2002;66:1497-500.. 2002;66:1497-500.

Knee Structure & Disorders. Outline Structure Skeletal Soft tissue Ligaments Menisci Bursae ...

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