- Discussion:
- rotational mal-alignment may lead to patellar malalignment and varus-valgus instability;
- the
valgus knee may have a lateral condyle which is deficient posteriorly;
- therefore, use of the posterior condyles as a reference, may lead to relative internal rotation of the femoral component;
-
AP Axis Method:
- line drawn perpendicular to the AP axis of femoral trochlea will most often orient the AP cutting guide in 4 deg of external rotation;
- use a rod placed along the deepest part of the patellar groove and the center of the intercondylar notch for proper orientation;
- when this method is used in a knee w/ a deficiency of the posterior aspect of the lateral femoral condyle,
there may be the perception that the cut will be made in extreme external rotation (as well as under-
resection of the lateral femoral condyle);
-
pitfalls:
- this method should not be used in revision knees in which the AP landmarks have been destroyed;
Femoral Rotational Alignment Based on the AP Axis, in TKR in a Valgus Knee.
J. Arima MD, L.A. Whiteside MD, D. McCarthy, and S.E. White.
JBJS. Vol. 77-A. No 9. Sep 1995.
