Frank R. Ebert, MD Union Memorial Hospital Baltimore, Maryland

1. TOTAL KNEE ARTHROPLASTY Frank R. Ebert, MDUnion Memorial HospitalBaltimore, Maryland

2. Total Knee Arthroplasty • Goal • Restore mechanical alignment • Restore joint line

3. Normal Knee Anatomy • Position in single leg stance • Mechanical axis valgus 3º • Femoral shaft axis valgus 6º • Proximal tibia varus 3º

5. Total Knee Arthroplasty • Radiographic Evaluation • Standing full length – AP • Standing AP • Extension/Flexion laterals • Tunnel view • Sunrise view

7. Total Knee Arthroplasty • Radiographic Evaluation • Weight Bearing X-rays • Extent of joint space narrowing • Ligament stretch out • Subluxation of femus on tibia

9. Total Knee Arthroplasty • Radiographic Analysis • Anatomic Axis – Femur • Line that bisects the medullary canal of the femur • Determines the entry point of the femoral medullary guide rod

11. Total Knee Arthroplasty • Radiographic Analysis • Mechanical Axis – Femur (MAF) • A line from center of femoral head to center of distal femur

13. Total Knee Arthroplasty • Radiographic Analysis • Anatomic Axis Tibia (AAT) • A line that bisects the medullary canal of the tibia • Determines the entry point of the guide rod

15. Total Knee Arthroplasty • Radiographic Evaluation • Mechanical Axis – Tibia (MAT) • Line from center of proximal tibia to center of ankle • Proximal tibia is cut perpendicular to (MAT)

17. Issues with Surgical Techniques • Traditional Joint Line Orientation • Tibial cut perpendicular to the MAT • Femoral shaft at a valgus angle 5º to 8º valgus based off the ong standing x-ray

19. Surgical Technique • Incision — straight longitudinal incision • Tissue handling key • Avoid flaps • Preserve soft tissue flap about the patella

21. Surgical Technique • Remember 7cm Rule between incisions

23. Exposure options — Subvastus / midvastus u Routine knee replacements z Quicker rehab — Medial parapatellar / midline u Difficult total knee — obese patients u Revisions Issues with Surgical Techniques

26. MIS vs MINI TKA • Capsulotomy only? • Mid vastus? • Sub vastus? MIS

27. MIS vs MINI TKA • Mid vastus? • Sub vastus? • Quad sparing? MIS

28. Anatomic Variations of VMO Insertion Type I-High Insertion Area of Variation Type II-Pole Insertion Type III-LowInsertion

29. Type I- High VMO Insertion Area of extended retinaculum Muscle Insertion Retinacular Incision

30. Type II-Pole Insertion Capsular or Retinacular Incision Muscle Insertion

31. Type III-Low VMO Insertion Area of Extended VM Muscle Insertion

32. Issues with Surgical Techniques • Alignment • Extramedullary vs Intramedullary •  Accuracy vs increased PE risk •  Femur – Intramedullary • z Overdrill opening and insert slowly IM guide • z Caution with bilateral Total Knee Arthroplasty •  Tibia – Extramedullary

34. Issues with Surgical Techniques • Femoral Rotation • Landmarks • Posterior femoral condyles • Epicondyles 5º external rotation to the posterior condyles

38. Issues with Surgical Techniques • Femur • Measured resections: equal bone distally and posteriorly • Tensioning devices & ligament releases • Do not alter bone resection for ligament tightness

40. Issues with Surgical Techniques • Tibial Component Rotation • Transmalleolar axis • Posterior tibial plateau • Tibial tubercle — lies lateral

44. Malalignment • Tibial Component • Internally Rotated • Tubercle Too Lateral

46. Management of Deformity • 1. Release the tight side of the deformity • 2. Tighten the loose side • 3. Accept some residual soft tissue imbalance • 4. Combination

48. Surgical Techniques • Varus Knee • 1. Pes anserinus • 2. Joint Capsule • 3. Deep Tibial Collateral • 4. Semimembranosus • 5. Posterior Medial Capsule