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Techniques in primary total knee arthroplasty
- 2. TECHNIQUES IN PRIMARY TOTAL KNEE ARTHROPLASTY: Balancing ! Douglas E. Padgett, M.D. Adult Reconstruction and Joint Replacement Hospital for Special Surgery New York, New York
- 3. DDIISSCCLLOOSSUURREESS None Relatedto the topic of this presentation Consultant: Mako, Stryker AAHKS: Board Member
- 4. Success in TKR Basic tenets of Dr. John Insall: – TKR should be thought of as a soft tissue operation – Failure to address the soft tissue envelope will result in: Pain Stiffness Laxity
- 5. “Thinking is thehardest work there is, which is the probable reason so few engage in it “ Henry Ford American entrepreneurr
- 6. FAILURE IN TKR Often can be traced back to original patho-anatomy Varus knee – Preop: Tight medial side – Trial Components: knee noted to be tight medially – Additional tibia resected – Result: knee “books open” medially
- 7. Failure in TKR: The Valgus Knee Complex patho-anatomy Rotation often difficult to discern Effect of deficiency of posterolateral condyle upon landmarks Insufficient lateral side release: results is unstable arthroplasty
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- 10. BALANCING THE VARUSKNEE: May be straight forward Items for consideration: – Fixed versus flexible – Tightness: Flexion Extension or both ! – Osteophytes – Bone Loss – Subluxation and or effect upon rotation
- 11. The Varus Knee: At times, a surgical challenge
- 12. APPROACH TO THE VARUS KNEE Standard medial parapatella approach Sharp dissection onto the proximo-medial tibia Dissection interval above the pes but below the joint line Subperiosteal elevation
- 13. The Varus Knee Remove all osteophytes STOP !!! – Assess ligamentous / soft tissue tightness before proceeding
- 14. RELEASE OF THEFIXED VARUS KNEE TIGHTNESS IN EXTENSION – Posterior ½ of the superficial MCL is primary factor – Anteromedial capsule can also contribute
- 15. RELEASE OF THEFIXED VARUS KNEE Tightness in Flexion – Anterior ½ of the superficial MCL – Semi-membraneossus and posteromedial capsule are tight
- 16. FIXED VARUS KNEE: FLEXION Check gap symmetry (medial and lateral sides) – Release anterior portion of superficial MCL Flexion space should not be excessively tight (I prefer some ability to translate forward)
- 17. FIXED VARUS KNEE: EXTENSION Sequential subperiosteal elevation of posterior portion of superficial MCL Ensure symmetry medial and lateral sides Knee must come to full extension !
- 18. ROLE OF BONERESECTION EFFECT UPON BALANCING While majority of balancing is soft tissue in nature: – tibial resection in coronal plane (varus-valgus) will effect soft tissues – Femoral rotation clearly affects soft tissue tension especially in flexion
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- 20. THE VALGUS KNEE Fixed vs correctable Associated bone loss Tightness: – Flexion ? – Extension ? – Both ? Status of MCL
- 21. STEP #1: EXPOSURE/ RESECTION Medial parapatella Minimal medial side release Tibial resection: – Minimal cut perpendicular to shaft Femoral resection: – I favor 2-3 degrees off of femoral line
- 22. FLEXION SPACE RELEASES Laminar spreader is the best device Pie-crusting of the posterolateral capsule and arcuate complex Leave the popliteus intact if possible. – Can result in flexion instability in varus
- 23. EXTENSION SPACE RELEASE Tight structures: – ITB – Posterolateral capsule Pie-crusting technique with SLOW gradual releases work best in my hands.
- 24. FINAL PRODUCT: Ligamentbalance: M=L Gap Balance: Flexion=Extension
- 25. THE VALGUS KNEE Adhering to the concept of sequential releases, majority of knees can be corrected with the use of additional constraint from the articulation.
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- 27. THE FLEXION CONTRACTED KNEE Considerations: – Definition: 15 degrees or greater loss of extension – ? Length of contracture – Status of skin, prior incisions – Neurologic exam
- 28. THE FLEXION CONTRACTED KNEE Deformity Bone loss Patella height
- 29. THE CONTRACTED KNEE: Surgical Technique May require extensile approach if knee is stiff Start with standard resection Remove all osteophytes
- 30. THE CONTRACTED KNEE: Soft Tissue Work PCL recession if using CR knee Posterior capsular release Posterior capsular stripping up to level of gastroc
- 31. THE FLEXION CONTRACTED KNEE: Bone Resection Optional distal femoral cut Effectively decrease the extension space ? How much can you take ? – DO NOT COMPROMISE COLLATERALS !! If unstable: constraint
- 32. THE CONTRACTED KNEE: POSTOP CARE Emphasis on extension No pillows under knee Pain control Dynamic splinting but watch the skin !! Role for manipulation is not clear!
- 33. TOTAL KNEE ARTHROPLASTY RECURVATUM
- 34. RECURVATUM Seen predominantly in neuromuscular diseases: – Polio – Neuropathic joints – Spinal cord patients Can occasionally be seen in rheumatic conditions
- 35. RECURVATUM: Options Hyperextensionup to 20 degrees: – Attempt to “overstuff” the extension space – Must balance the temptation to leave the knee with a flexion contracture: If recurvatum is due to quad weakness, flexion contracture will lead to knee giving out !
- 36. RECURVATUM Use ofdistal femoral augmentation – Will tighten the extension space while not affecting the flexion space Limits of distal femoral augments: – 10-15 mm – Usually require use of femoral stems
- 37. RECURVATUM Posterior stabilized implants are preferred Less constraining implants may lead to instability
- 38. RECURVATUM Reliance upon standard implants will lead to excessive anterior polyethylene impingement Wear and or loosening is clearly a consequence
- 39. RECURVATUM: The largerdeformities In instances where there is more than 20 degrees of recurvatum: consider a more constrained implant with an extension stop DO NOT RELY UPON STANDARD CONDYLAR DESIGNS !!
- 40. Primary TKR: Summary Understanding of pathoanatomy crucial Correction of deforming forces is vital to successful outcome Know the limits of your prosthetic implant
- 41. THANK YOU FORYOUR ATTENTION !