Extract
The premise of this article, and the scientific exhibit upon which
it is based, is that the morphologic shape of the distal aspect of the femur
and its relation to the tibia and the patella dictates the kinematics of the
knee. The morphologic and kinematic characteristics of the knee presented in
earlier
exhibits1,2
at the 2001 and 2003 Annual Meetings of the American Academy of Orthopaedic
Surgeons demonstrated the following relationships. The location and
orientation of the femoral sulcus is lateral to the midplane between the
femoral condyles and is oriented between the anatomic and mechanical axes of
the femur (Figs. 1-A and
1-B). The center of the femur
in cross section is offset, medial and anterior, to the center of the tibia,
and these offset cross sections are rotated relative to each other in the
pathologic knee (Fig. 2). A
single, fixed flexion-extension axis of the knee is centered in the asymmetric
cylindrical femoral condyles (Fig.
3). These and other
observations1-8
of distal femoral morphology and their relationship to knee kinematics form
the basis for the additional studies in the present article. These new studies
relate the morphology of the femur (condyles and epicondyles) and the axis of
the limb (mechanical axis) to the location and orientation of the
flexion-extension axis of the knee in three-dimensional space.