March 3, 2012 New England Baptist Hospital AORN Anthony Schena, MD

DISCLOSURES

Who

Patellofemoral Joint Articulation between the patella and the trochlea Trochlea designed to prevent lateral subluxation Soft tissue structures assist/prevent this as well VMO Tethers to the ITB/VL/VMO MPFL Medial retinaculum Patella has the thickest cartilage in the body Forces approach 7 x body weight with routine exercises

PF joint

Forces

Patella Increases the strength of the quad ½ body wt with level walking 3.3 x wt with stairs From 0-90 ° pressure goes from inf to sup pole Odd facet engaged at 110°

Injury

Pathophysiology of Disease Causes of trauma to the PF joint Acute Direct impact-dashboard Fracture Dislocation Tendon rupture Chronic Overload with activities Weight Lower limb Malalignment OCD

Direct Impact/Contusion Damages cartilage along PF joint Gradual wearing down vs acute cartilage defect Treat acute chondral loss if possible Surgically repair ACI/OATs ? Offload

Fracture If displaced, treat surgically Need anatomic alignment Can still breakdown over time ? Pain from hardware

Dislocation One time vs chronic laxity Stabilize Patella before damage becomes too severe Even with cartilage breakdown, need to stabilize joint

Weight/activities Increases dramatically with activities that stress the patellofemoral joint (up to 7-8 x body wt) Stairs, squatting, kneeling, walking/hiking downhill Modest weight loss can be helpful Change activities Address other lower extremity issues

Lower Extremity Malalignment Pes Planus (flat feet) Tibial torsion Genu valgum (knocked knees) Hypoplastic lateral trochlea Excessive femoral anteversion Weak hip abductors/External rotators

Miserable Malalignment Internally rotated hips Genu valgum Hyperpronation/flat feet

The Patient

Physical Exam History: repetitive overuse vs acute event/trauma Ask 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 toes In shorts, both knees exposed Gait analysis before or after exam while in shorts

Exam Hips ROM/flexibility ITB, abductors, adductors, flexors, extensors, ERs OBER test Muscular strength

OBER TEST Test ITB

Exam Knee ROM Effusion/swelling/general appearance Flexibility Prone Quad Also good check for femoral anteverion-knee flexed to 90 and IR until greater Trochanter is Maximally prominent laterally Muscular Tone/symmetry VMO Balance Thigh Circumference Extensor lag/VMO lag

Patella Mobility/translation-apprehension Tenderness Tracking through ROM J sign Tilt Q angle Normal at or less than 15 degrees Position of the Tibial tubercle

Tracking

Q angle

In the End…

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

Isolated Patellofemoral OA Location of Disease Entire patella versus certain quadrant Age History/Exam Pain with stairs/squatting Effusions Crepitus Activity level

Imaging X-rays Merchant View Tilt CT scans MRI Subchondral cysts/cartilage loss

What can we do?

Treatment Non-operative NSAIDs Strengthening VMO/Closed Chain Patella tracking braces Activity modification Weight loss Viscosupplementation Cortisone

Arthroscopy Debride damaged cartilage Lavage knee Schonholtz/Long-49% G/E at 40 months Federico/Reider – 58% traumatic/41% atruamatic G/E +/- lateral release Isolated patella or trochlear lesions Microfracture/abrasion chondroplasty

ACI Controversial Poor long term studies Most 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 Osteotomy Unloads the Patellofemoral joint Can Correct Malalignment Useful for patients with articular damage to the lateral and inferior patella (AMZ) and the entire patella (straight osteotomy)

TTO

Recovery 6 weeks for osteotomy to heal Can weight bear in brace Start PROM Once ambulatory- work on quad strength, balance, functional recovery May still need to treat Effusions, anterior knee pain Weight control Activity modification

Patellofemoral Resurfacing Replace patella cartilage loss with plastic component Stryker Triathalon X3 patella vs inlay UHMWE polyethylene Trochlear lesion replaced with inlay metal component Cobalt-Chromium alloy Titanium Stud assssdsa Arthrosurface ™

PF Tray

ProSports Outcomes 60 patients over four years Three failures One converted to a TKA Two converted from first generation to second generation trochlear implant One patient just 6 weeks out with tracking issue-no pain/very weak VMO May require further surgery

Patellofemoral Replacement

Patellectomy ∙Excise patella ∙Lose mechanical advantage ∙Expect extensor lag

Thank You