Essentially, the anatomy of each femur is special
In spite of the obvious simplicity of the use of instrumentation based at the posterior condylar axis to set femoral issue rotation, there are negative aspects to this method. Essentially, the anatomy of each femur is special. The selection to externally rotate the slicing courses 3 to four levels with regards to the posterior condylar axis to set femoral rotation become derived from imply facts. While externally rotating the femur three or four tiers can be accurate in a majority of instances, there are definite outliners. Measured the angles among the tangent line of the posterior condylar surfaces, the AP axis described via Whiteside, and the transepicondylar line in 100 knees undergoing TKA. They found various -1 to 7 stages of external rotation between the epicondyle line and the posterior condylar line.