1. Evolving Technique: PFA in Young Patients – a Case Approach
Phil Davidson, MD
Davidson Orthopaedics
Park City, Utah
Ortho Summit, Las Vegas Dec 6, 2018

2. Disclosures
none

3. Our Case: 38 year old Firefighter with anterior knee pain, now unable to manage ladders
She has already had PT, NSAID, Bracing and injections to include corticosteroid and HA
No trauma hx
Scope chondroplasty with no relief 2 yrs ago
Pain worse with descent
Pain exclusively in PF area

4. Plain Radiographs

5. Radiography Our patient: Sulcus angle: 132º Congruence angle: 30º
Merchant Xray- need dedicated board/jig
>145 considered “shallow”
Our patient:
Sulcus angle: 132º Congruence angle: 30º

6. Radiography- Patellar Height
Caton-Deschamps (CD) Ratio (X/Y)
NL appx
Very handy to use digital measuring tools
Patellar Alta and Baja

7. MRI Imaging – our patient TTTG 15mm (>18 TTO) CD ratio 1. 1 (>1
MRI Imaging – our patient TTTG 15mm (>18 TTO) CD ratio 1.1 (>1.3 Alta)

8. Audience Participation
Activity modification, bracing, more non surgical RX
TKA
Biological Resurfacing
TTO alone
PFA with prox realignment
PFA with TTO

9. How should we approach options here?
Etiology
Anatomy
Biologic vs Prosthetic

10. Etiology of PF degeneration
Traumatic (blow)
Malalignment
Morphology
Instability
Systemic DJD

11. The majority of isolated PF DJD in “younger patients” is associated with abnormal anatomy 1. Abnormal Morphology 2. Abnormal Geometry Rotation Height Version 3. Generalized Laxity
28 year old female

12. Morphology
Both patellar and trochlear morphology need to be identified in considering treatment options
Abnormal morphology can create stresses on repairs
Implant choice affected by trochlear and patellar shapes
Wiberg Classification
Dejour Classification

13. Geometry Geometric alignment needs to be considered in 3-D
Patellar position M-L
Valgus knee
Patellar “tilt”
Femoral version
Patellar height
Correction targeted at specific malalignment/rotation

14. Limb Rotation – femur and tibia
Both Femoral Version AND Tibial Torsion bear on PF forces
Femoral Anteversion
NL female 13
External Tibial Torsion
NL female 27

15. Extensor Realignment Medial Plication Lateral Lengthen, not release
Need “normal” tissue to plicate
i.e. not markedly lax
Easily incorporated into PFA
“Selective” lateral release, preserving underlying synovial layer–
part of realignment, not alone!

16. MPFL combo with PFA
This is indicated when DJD coexists with recurrent instability and/or laxity
Need to protect patellar implant
Avoid patellar bone tunnel techniques

17. TTO or Trochleoplasty with PFA
Medialization can correct for increased TT-TG or TT-PCL
Move proximal to address patellar baja
Distalize to address patellar alta

18. Biologic or Prosthetic Resurfacing ???? Key decision making points
Multifactoral decision
Lesion: focal or diffuse
Patient Factors
Comorbidities
Osteophytes, catabolic environment
Bipolar
Resources Available

19. Biological Options Scaffolds Cell Therapy Osteochondral Grafts
Autogenous
Limited use
Allograft
Fresh stored
Cryopreserved
Cartilage Grafts
Minced, ground, lamellar
Non-viable (scaffold)

20. Onlay vs Inlay Joint Resurfacing - Patella
Inlay useful for focal defects and for “normal” morphology
Onlay needed for diffuse chondral disease or “abnormal” morphology
I use Onlay 98% of cases

21. Onlay vs Inlay Joint Resurfacing for FTG
Onlay device replaces anatomy, but may add unwanted volume
Inlay device based on ambient anatomy
Inlay device allows for concurrent realignment
Inlay device inherently stable
Inlay typically more anatomic
Inlay allows easier conversion to TKA
Onlay
Inlay

22. Our case Operative images

23. Operative Images and alignment
Operative Images and alignment. I did Prox Realignment with medial plication and lateral lengthening
Extension
Flexion

24. Post op images

25. Thank You phildavidsonmd@gmail.com