In utero and postnatal positioning of the legs and hips produces stresses that bring about these rotational deformities of the femoral neck. The true incidence of anteversion and retroversion is not known, but the former is much more common and occurs twice as frequently in girls as in boys.

Femoral anteversion produces kissing knees, toeing-in, and a clumsy gait. With the patella in neutral position, the greater trochanter of the femur lies posterior to the lateral, longitudinal midthigh line. External rotation is decreased and internal rotation of the hip in extension is increased (normally 35 to 45 degrees for both). External rotation of the hip in flexion is normal, however. The findings in retroversion are the opposite of those found in anteversion of the femoral neck. Imaging is only required in cases of extreme anteversion or retroversion.