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Total Knee Arthroplasty in Varus Knee

Total Knee Arthroplasty in Varus Knee. H.Makhmalbaf MD Consultant Orthopaedic & Knee Surgeon Ghaem Hospital Medical School. The most important factor in maintaining satisfactory long-term outcome in TKA is anatomic alignment This depends significantly on ligamentous balance.

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Total Knee Arthroplasty in Varus Knee

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  1. Total Knee Arthroplasty in Varus Knee H.Makhmalbaf MD Consultant Orthopaedic & Knee Surgeon Ghaem Hospital Medical School

  2. The most important factor in maintaining satisfactory long-term outcome in TKA is anatomic alignmentThis depends significantly on ligamentous balance

  3. The most favorable results are observed with femorotibial angle 3-7ovalgus , the tibial component in neutral,& the femoral component in 4-6o valgus

  4. The typical patient • Severe varus deformity • Some varus alignment since childhood • H/O medial menisectomy • Gradually progresses • Lateral subluxation of the tibia on the femur

  5. Exposure • Standard medial parapatellar arthrotomy • Resect medial meniscus • Release deep MCL • Resect ACL • Externally rotate & deliver the tibia • Remove all osteophytes

  6. Mediolateral Balancing • Ligament balance in flexion & extention are interrelated (unlike valgus knee) • In a varus knee , the knee should be balanced in extention first then in flexion

  7. Shift & resect technique • Tibia is delivered in front of the tibia • Initial conservative tibial resection • Based on the intact lateral side • 10mm lateral resection • Angle of resection is perpendicular to the long axis of the tibia & 3-5o posterior slope • Choose tibia one size smaller

  8. Shift & resect • Choose tibia one size smaller & • Shifted laterally to the edge of tibia • Align tibial rotation with tibial tubercle • Outline the nucapped portion of tibia • Free the MCL from bone • Resect bone perpedicular

  9. Formal MCL release from the tibia • Release deep MCL • Posteromedial capsule • Remove osteophytes • Release PCL • Resect PCL & put PS knee

  10. Distal femoral resection • Pre-op X-ray • Varus in the femoral shaft ? • Usually 5-7deg.cut • More resection of medial fem. condyle • The amount of resection depends on the thickness of metallic femoral component

  11. Femoral component rotation • Establish a balanced, symmetric flexion gap to maximize flex. Stability • In varus knee balance in ext.1st • Use the Whiteside line or trans epi. • 30 external rotation • Then posterior condyles in flexion

  12. Tibial bone stock deficiency • Medial tibial plateau is always deficient in varus knee • Resect enough bone not too much • Bone graft • Cement & screws • Metal wedges • Allograft

  13. Residual lateral laxity • How much laxity is acceptable • The bony alignment should not be in varus • The lateral should not gap open on the tab • Correct significant laxity • More medial release • Fibula head advancement?

  14. summary • Tibia is responsible for varus • Release MCL, remove osteopytes • Bone resection, undersize, sift • Balance flexion gap • PCL retention in severe varus? • Release PCL ? • Accept some residual laxity if • Fill bony defects in tibia

  15. Thank you

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