Total Knee Arthroplasty (TKA): Surgical Philosophies

The primary goal of a TKA is to provide a painless, stable knee with functional range of motion. Achieving perfect soft tissue balance and proper component alignment is critical. Two dominant philosophies exist for establishing this balance.

📏 Measured Resection

Relies on bony landmarks (e.g., epicondylar axis, Whiteside's line, posterior condylar axis) to dictate femoral component rotation and bone cuts.

  • Bone cut first: Resect bone equal to the thickness of the implant.
  • Soft tissue second: Ligament releases are performed after bone cuts to balance the gaps.
  • Advantage: Accurately restores the joint line.

⚖️ Gap Balancing

Relies on soft-tissue tension to determine the bony resections. The goal is to create equal rectangular extension and flexion gaps.

  • Soft tissue first: Release ligaments to achieve a rectangular extension gap.
  • Bone cut second: The femur is rotated to ensure the flexion gap matches the extension gap.
  • Advantage: Ensures excellent coronal stability throughout the range of motion.

High-Yield Clinical Pearl

In a severe valgus knee, isolated gap balancing may lead to excessive internal rotation of the femoral component. Surgeons often use a hybrid approach to prevent patellofemoral maltracking while ensuring joint stability.

ARTHROPLASTY

Which factor is most strongly associated with early aseptic loosening of the acetabular component after total hip arthroplasty?

A Use of ceramic femoral heads
B Polyethylene wear debris leading to osteolysis
C Use of cemented stems
D Small femoral head size