Patellofemoral Osteoarthritis

Patellofemoral OsteoarthritisMarch 3, 2012New England Baptist HospitalAORNAnthony Schena, MD

DISCLOSURES

Who

Patellofemoral JointArticulation between the patella and the trochleaTrochlea designed to prevent lateral subluxationSoft tissue structures assist/prevent this as wellVMO Tethers to the ITB/VL/VMOMPFLMedial retinaculumPatella has the thickest cartilage in the bodyForces approach 7 x body weight with routine exercisesPF joint

Forces

PatellaIncreases the strength of the quad body wt with level walking3.3 x wt with stairsFrom 0-90 pressure goes from inf to sup poleOdd facet engaged at 110

Injury

Pathophysiology of DiseaseCauses of trauma to the PF jointAcuteDirect impact-dashboardFractureDislocationTendon ruptureChronicOverload with activitiesWeightLower limb MalalignmentOCDDirect Impact/ContusionDamages cartilage along PF jointGradual wearing down vs acute cartilage defectTreat acute chondral loss if possibleSurgically repairACI/OATs? OffloadFractureIf displaced, treat surgicallyNeed anatomic alignmentCan still breakdown over time? Pain from hardware

DislocationOne time vs chronic laxityStabilize Patella before damage becomes too severeEven with cartilage breakdown, need to stabilize joint

Weight/activitiesIncreases dramatically with activities that stress the patellofemoral joint (up to 7-8 x body wt)Stairs, squatting, kneeling, walking/hiking downhillModest weight loss can be helpfulChange activities Address other lower extremity issuesLower Extremity MalalignmentPes Planus (flat feet)Tibial torsionGenu valgum (knocked knees)Hypoplastic lateral trochleaExcessive femoral anteversionWeak hip abductors/External rotatorsMiserable MalalignmentInternally rotated hipsGenu valgumHyperpronation/flat feet

The Patient

Physical ExamHistory: repetitive overuse vs acute event/traumaAsk about old MVA, sports injuries, instability episdoses, daily activities that cause pain, treatments that make the pain better (did they take NSAIDs the day of the exam)Exam:Hips to toesIn shorts, both knees exposedGait analysis before or after exam while in shorts

ExamHipsROM/flexibilityITB, abductors, adductors, flexors, extensors, ERsOBER testMuscular strength

OBER TESTTest ITB

ExamKneeROMEffusion/swelling/general appearanceFlexibilityProne Quad Also good check for femoral anteverion-knee flexed to 90 and IR until greater Trochanter is Maximally prominent laterallyMuscular Tone/symmetryVMOBalanceThigh CircumferenceExtensor lag/VMO lag

PatellaMobility/translation-apprehensionTendernessTracking through ROMJ signTiltQ angleNormal at or less than 15 degreesPosition of the Tibial tubercleTracking

Q angle

In the End

What are the other issuesConcomitant disease in the medial or lateral joint in a patient >50most likely will lead to a TKAWith intact menisci, could consider a resurfacing of the involved compartment and the PF joint

Isolated Patellofemoral OALocation of DiseaseEntire patella versus certain quadrantAgeHistory/ExamPain with stairs/squattingEffusionsCrepitusActivity level

ImagingX-raysMerchant ViewTiltCT scansMRISubchondral cysts/cartilage loss

What can we do?

TreatmentNon-operativeNSAIDsStrengtheningVMO/Closed ChainPatella tracking bracesActivity modificationWeight lossViscosupplementationCortisone

ArthroscopyDebride damaged cartilageLavage kneeSchonholtz/Long-49% G/E at 40 monthsFederico/Reider 58% traumatic/41% atruamatic G/E+/- lateral releaseIsolated patella or trochlear lesionsMicrofracture/abrasion chondroplasty

ACIControversialPoor long term studiesMost patients poor candidates due to chronicity of disease and degenerative changes to the underlying bone (cystic changes)When considered, need to address the underlying malalignment Off load the patellofemoral joint

Tibial Tubercle OsteotomyUnloads the Patellofemoral jointCan Correct MalalignmentUseful for patients with articular damage to the lateral and inferior patella (AMZ) and the entire patella (straight osteotomy)

TTO

TTO

Recovery6 weeks for osteotomy to healCan weight bear in braceStart PROMOnce ambulatory-work on quad strength, balance, functional recoveryMay still need to treat Effusions, anterior knee painWeight controlActivity modification

Patellofemoral ResurfacingReplace patella cartilage loss with plastic componentStryker Triathalon X3 patella vs inlay UHMWE polyethyleneTrochlear lesion replaced with inlay metal componentCobalt-Chromium alloyTitanium Stud

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Arthrosurface PF Tray

ProSports Outcomes60 patients over four yearsThree failuresOne converted to a TKATwo converted from first generation to second generation trochlear implantOne patient just 6 weeks out with tracking issue-no pain/very weak VMOMay require further surgeryPatellofemoral Replacement

PatellectomyExcise patellaLose mechanicaladvantageExpect extensor lag

Thank You

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