Evolving Technique Update: Getting the Patella in the Groove with a - - PowerPoint PPT Presentation

ADULT RECONSTRUCTION AND JOINT REPLACEMENT

Evolving Technique Update: Getting the Patella in the Groove with a Valgus Knee

Michael B. Cross, MD Assistant Attending Orthopaedic Surgeon

ADULT RECONSTRUCTION AND JOINT REPLACEMENT

Disclosures

• Consultant:
• Smith & Nephew
• Link Orthopaedics
• Exactech Inc.
• Intellijoint
• Acelity
• Theravance Biopharma
• Zimmer Biomet
• Honorarium
• Acelity
• Editorial Board
• Techniques in Orthopaedics
• Bone and Joint Journal 360
• Journal of Orthopaedics and Traumatology

ADULT RECONSTRUCTION AND JOINT REPLACEMENT

The Valgus Knee

• The valgus knee deformity is a

challenge in TKA

• Operation is harder when valgus

angle ≥ 10°and not correctable

• Observed in nearly 10% of patients

undergoing TKA

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ADULT RECONSTRUCTION AND JOINT REPLACEMENT

Anatomic Contributions to the Valgus Knee

Bone Loss

– Lateral cartilage erosion – Lateral condylar hypoplasia – Metaphyseal femoral and tibial plateau remodeling 4

Soft Tissues

 Tightening of the lateral

structures: – Lateral collateral ligament – Lateral PFL – Posterolateral capsule – Popliteus tendon – Hamstring tendons – Lateral head of the gastrocnemius – IT band

Combined

ADULT RECONSTRUCTION AND JOINT REPLACEMENT

Common Patellar Complications Post op

• Patellar stress FX
• Patellar instability
• Extensor mechanism disruptions
• Patellar maltracking
• Component wear
• Patellar component loosening
• Patellar component disassociation

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How do we prevent patellar complications, particularly maltracking?

ADULT RECONSTRUCTION AND JOINT REPLACEMENT

My Surgical Technique: The Medial Parapatellar Approach

• Not difficult to address lateral

side

• Becomes extensile by extending

further proximal onto quad tendon

• Limit medial dissection

– BUT… Still release of posteromedial structures to dislocate the knee

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ADULT RECONSTRUCTION AND JOINT REPLACEMENT

PREVENTION - Surgical Considerations

• Beware of internal rotation

and medialization of femoral component – Shifts the trochlear groove medially – Increase lateral retinacular strain

• Do not rely on the

posterior condyles of femoral component rotation! – Posterolateral condylar deficiency !!!

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Bolognesi Files

ADULT RECONSTRUCTION AND JOINT REPLACEMENT

PREVENTION - Surgical Considerations

• Beware of internal rotation and medialization of tibial component

– Causes tibia to externally rotate in flexion – Increases Q-angle

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ADULT RECONSTRUCTION AND JOINT REPLACEMENT

PREVENTION - Surgical Considerations

• Pay attention to the

anterior compartment!

• Avoid overstuffing the

patellofemoral joint by: – Anteriorization of the femoral component – Thick patellar component – Oversized femoral component

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Victor J. Which implant do I pick? A glossary of promises, Orlando, FL: 2008.

ADULT RECONSTRUCTION AND JOINT REPLACEMENT

PREVENTION - Patellar Positioning

• Resection that preserves at least 12-15mm remaining patella

thickness to anchor prosthesis

• Goal of positioning is to improve tracking & decrease wear

– Place medially and superiorly – Anatomic positioning of central dome (over medial sagittal ridge)

• Inside out lateral release of lateral tissue off patella

– Remove the lateral facet

ADULT RECONSTRUCTION AND JOINT REPLACEMENT

Patellar Tracking as a Final Check

• Good indicator of appropriate component positioning
• Good positioning reduces need for lateral retinacular release to

less than 5-10%

• Should track smoothly and contact femoral component

throughout ROM

• Always consider the effect of the tourniquet

ADULT RECONSTRUCTION AND JOINT REPLACEMENT

”Ok, I’ve done all that… Now what?”

ADULT RECONSTRUCTION AND JOINT REPLACEMENT

My steps to addressing the problem

• Take down the tourniquet first!
• When checking tracking make sure you are not externally

rotating the foot

• Slight lift off – clamp the arthrotomy together and test again
• No improvement

– Release lateral PFL

• No improvement

– Place two Kochers along medial arthrotomy and have my assistant pull medially – Release tight lateral retinaculum leaving capsule intact – I only do a full lateral release if nothing else works.

ADULT RECONSTRUCTION AND JOINT REPLACEMENT

Summary

• Technique for patellar alignment in the valgus knee must take

into consideration BOTH soft tissue and bone loss

• PREVENTION IS KEY to avoiding patellar problems

– Avoid IR of the femoral or tibial components – Avoid medialization of the femoral or tibial components – Place the Patella Medial and Superior in its anatomic position – Avoid overstuffing the patellofemoral joint

• Always check for smooth and continuous patellar tracking

BEFORE AND AFTER tourniquet deflation – DO NOT PERFORM A LATERAL RELEASE UNTIL TOURNIQUET IS DOWN

ADULT RECONSTRUCTION AND JOINT REPLACEMENT

Peel tissue off lateral facet and remove lateral facet Release Lateral PFL Release Lateral Retinaculum, preserving the capsule Full lateral release

Summary

ADULT RECONSTRUCTION AND JOINT REPLACEMENT

THANK YOU