Intraoperative anatomic study of 100 arthritic knees measuring the angles between the transepicondylar axis, Whiteside's AP axis, posterior condylar tangent, and trochlear line to determine which landmark most reliably guides femoral component rotation in TKA.
When setting femoral component rotation in TKA, use the transepicondylar axis as your primary reference — its variability is half that of Whiteside's AP axis, it is never significantly internally rotated relative to the posterior condyles, and it remains consistent across varus, neutral, and valgus knees; cross-check with the AP axis but do not rely on the AP axis alone, especially in trochlear dysplasia or severe valgus where it will over-externally rotate the component, or in varus knees where it can internally rotate it.
Intraoperative anatomic study of 100 arthritic knees measuring the angles between the transepicondylar axis, Whiteside's AP axis, posterior condylar tangent, and trochlear line to determine which landmark most reliably guides femoral component rotation in TKA.
When setting femoral component rotation in TKA, use the transepicondylar axis as your primary reference — its variability is half that of Whiteside's AP axis, it is never significantly internally rotated relative to the posterior condyles, and it remains consistent across varus, neutral, and valgus knees; cross-check with the AP axis but do not rely on the AP axis alone, especially in trochlear dysplasia or severe valgus where it will over-externally rotate the component, or in varus knees where it can internally rotate it.