An increased degree of femoral version, which is defined as the angular difference between axis of femoral neck and transcondylar axis of the knee. Thus, femoral anteversion is an inward twisting of the femur that causes the knees and feet to turn inward.
Comment:
Femoral neck anteversion (FNA), also called femoral torsion or femoral version, is the angle between the projection of two lines in the axial plane perpendicular to the femoral shaft; one line going through the proximal femoral neck region and the second one through the distal condylar region, indicating the degree of twist of the femur. Excessive femoral anteversion is a common cause of in-toeing that first presents in early childhood. See Figure 1 of PMID:32579722.