Femoral torsion

Femoral torsion may consist of anteversion or retroversion. Anteversion (a cause of in-toeing) means the femoral neck is externally rotated relative to the femoral condyles; retroversion means the femoral neck is relatively internally rotated.

The angle used to determine version is formed by a line through the long axis of the femoral neck and another line formed by the posterior borders of the femoral condyles. For ease of measurement, the condylar line has been moved upward in the drawing of femoral retroversion above.

Anteversion typically resolves as a young child grows. Normal femoral anteversion is approximately 15 to 25 degrees in children and 8 to 15 degrees in adults. Unresolved anteversion or retroversion can lead to problems at the hip or knee.