Patellofemoral Osteoarthritis

1. Patellofemoral Osteoarthritis March 3, 2012 New England Baptist Hospital AORN Anthony Schena, MD

2. DISCLOSURES

3. Who

4. 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

5. PF joint

6. Forces

8. 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°

9. Injury

10. 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

11. 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

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

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

14. 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

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

16. Miserable Malalignment Internally rotated hips Genu valgum Hyperpronation/flat feet

17. The Patient

18. 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

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

20. OBER TEST • Test ITB

21. 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

22. 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

23. Tracking

24. Q angle

26. In the End…

27. 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

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

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

30. What can we do?

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

32. 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

33. 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

35. 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)

36. TTO

37. TTO

38. 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

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

40. PF Tray

50. 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