This review compares two techniques for setting femoral component rotation in total knee arthroplasty. Measured resection uses bony landmarks (TEA, AP axis, posterior condylar axis). Gap balancing positions the femoral component parallel to the resected tibia with collaterals equally tensioned. The authors weigh the evidence for each.
Femoral component rotation is the variable that determines flexion gap balance, and getting it wrong produces patellofemoral instability, anterior knee pain, arthrofibrosis, and flexion instability.
The central mental model: measured resection trusts bony anatomy, gap balancing trusts soft tissue tension. Landmarks vary widely between patients and are hard to identify, which is why measured resection accumulated more condylar lift-off in the cited data.
Know the deformity-specific traps. In a valgus knee the posterior lateral condyle is hypoplastic, so the posterior condylar axis drives internal rotation. In severe trochlear dysplasia the AP axis drives excessive external rotation.
Also memorize the tibial cut relationship: varus cut leads to internal rotation, valgus cut leads to external rotation. This is why a precise perpendicular proximal tibial cut is the anchor of any gap balancing sequence. This is a review by advocates of gap balancing, so weigh its conclusions as an argued position rather than settled evidence.
This review compares two techniques for setting femoral component rotation in total knee arthroplasty. Measured resection uses bony landmarks (TEA, AP axis, posterior condylar axis). Gap balancing positions the femoral component parallel to the resected tibia with collaterals equally tensioned. The authors weigh the evidence for each.
Femoral component rotation is the variable that determines flexion gap balance, and getting it wrong produces patellofemoral instability, anterior knee pain, arthrofibrosis, and flexion instability.
The central mental model: measured resection trusts bony anatomy, gap balancing trusts soft tissue tension. Landmarks vary widely between patients and are hard to identify, which is why measured resection accumulated more condylar lift-off in the cited data.
Know the deformity-specific traps. In a valgus knee the posterior lateral condyle is hypoplastic, so the posterior condylar axis drives internal rotation. In severe trochlear dysplasia the AP axis drives excessive external rotation.
Also memorize the tibial cut relationship: varus cut leads to internal rotation, valgus cut leads to external rotation. This is why a precise perpendicular proximal tibial cut is the anchor of any gap balancing sequence. This is a review by advocates of gap balancing, so weigh its conclusions as an argued position rather than settled evidence.