patellofemoral instability perfecting the distal

Patellofemoral Instability: Perfecting the Distal Realignment and - PowerPoint PPT Presentation

Patellofemoral Instability: Perfecting the Distal Realignment and Outcomes Jason L. Koh, M.D. Board of Directors Endowed Chairman North Shore University Health System Clinical Professor University of Chicago Board Member, Patellofemoral

  1. Patellofemoral Instability: Perfecting the Distal Realignment and Outcomes Jason L. Koh, M.D. Board of Directors Endowed Chairman North Shore University Health System Clinical Professor University of Chicago Board Member, Patellofemoral Foundation

  2. Thoughts • Bone trumps soft tissue • Significant bony malalignment = bony procedure • Repairs of weak tissue are…weak • Primary repair increased failures with dysplasia • Fixing pathoanatomy may require several parts

  3. Who needs a tibial tubercle osteotomy? • Instability – patients with significant bony abnormality / alta • Unloading chondral lesions • Can be combined with cartilage procedures

  4. Anterior Tibial tubercle – Trochlear groove (ATT-TG) Distance • Objective, reliable • > 15 mm abnormal • > 20 mm “Objective patella instability (OPI)” • I would consider distal realignment • Can be done w/MRI • (Dejour)

  5. Patella height • ALL RATIOS 1:1 + 0.2 • Blackburn-Peel (most reliable) A:Y • Caton A:X • Insall-Salvati B:Z • Consider distalization if >1.4

  6. Tubercle realignment for instability • No need for significant anteriorization • Relatively flat shingle • Consider distalization by up to 1 cm if necessary (usually not) • Goal is about 1.2:1 ratio

  7. Patella alta – goal 1.2

  8. Unloading procedures (tibial tubercle) • Fulkerson oblique osteotomy • Anterior – medialization of tubercle • Very reliable for appropriate lesion

  9. Biomechanics of Fulkerson osteotomy • Anteriorize – shifts load proximal • Medialize – shift load medial

  10. Results (Pidoriano and Fulkerson) • results depending on location of defect • distal , lateral facet of patella or lateral trochlea • NOT for CENTRAL, DIFFUSE, or PROXIMAL

  11. Technique: Workup • MRI if lesion appropriate • Distal, lateral patella; lateral trochlea

  12. Assess articular cartilage arthroscopically • Evaluate for other articular cartilage lesions

  13. Lateral cartilage lesion

  14. Skin incision centered on tubercle • For smaller degrees of correction, can use shorter shingle (5cm) • For significant anteriorization, consider longer shingle (7cm)

  15. Define medial and lateral borders of tubercle and patella tendon • Open anterolateral fascia and elevate musculature • Avoid going deep to septum • Note small perforators at proximal edge • Determine obliquity of shingle • Taper shingle to distal tip, leave 2-3 mm distally unless distalizing • Osteotomy angled medial to lateral and proximal to distal • use small oscillating saw (ACL type saw) and irrigate • Soft tissue protected with retractors

  16. Oscillating saw

  17. Finish proximal portion with curved osteotomes

  18. Osteotomes

  19. Note oblique osteotomy

  20. Osteotomy anteromedially translated • Measure distance translated • Provisionally fixed with k wire

  21. Measurement

  22. Assess patellofemoral tracking arthroscopically to see if lesion is unloaded

  23. Scope

  24. Fix tubercle with lag technique • I use 2 4.0 headless variable pitch screws or 3.5 screws • Can use 4.5 screw – but will have to remove many • Knee is flexed to 90 degrees and posterior neurovascular tissues allowed to fall away

  25. Fixation

  26. Stabilize shingle

  27. Assess tubercle radiographically in AP

  28. And lateral; grab posterior cortex with screw

  29. Closure and Rehab • Leave fascia open • Allow ROM • Patella mobilization • Progress to full weightbearing at 6 – 8 wks • Early WB runs a risk of later stress fracture of the tibia at proximal osteotomy site (Fulkerson, SCOI experience) • CPT code distal realignment 27418

  30. Caveats • Avoid over medialization • Watch patella tracking after provisional fixation • I try for slight lateral initial touch of patella • Neurovascular structures are close posteriorly (Kline et al) • Avoid early weightbearing (Fulkerson, Stetson) • Risk of nonunion of tuberosity relatively small

  31. Results • Allow progression of activity • Typically will take 4-6 months for sport • Extensor lag may persist for 6-8 months • May have progression of patellofemoral arthritis requiring further surgery; however, in most cases, results are durable • Combined results with cartilage procedures may be better

  32. Results • Roux-Goldthwaite: 14% redislocation, 25% arthritis (Sillanpaa CORR 2008) • AMZ: 31 patients, 4.4 yrs: 1 redislocation, 1 tip fx, 2 hardware removal (Ding Injury 2015) • Fulkerson 93% good-excellent at 5 years • Jim Bradley – AJSM 2010 – 41 Fulkersons in 34 athletes – avg age 20; mean fu 46 months • 97% return to sport w/o recurrence

  33. Complications • Nonunion – may have delayed union • Preservation of tip attachment may decrease • Shingle fracture – 1 case reported by Cosgarea • Proximal tibia fracture – associated with early WB (SCOI, Fulkerson) • (I had one associated with a fall down the stairs)

  34. Overmedialization

  35. Tubercle realignment: TTTG >20 mm or patella alta ratio >1.4 • Avoid over medialization • Goal distalize 1.2; medialize to TTTG 10-15 mm

  36. Over distalization

  37. Revision

  38. Thank you!

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