Why does hip dysplasia cause leg to be or function shorter?

Hip dysplasia: Hip dysplasia causes the ball and socket joint to be out of whack, so the hip isn't nestled in the hip joint like it should be. This causes the femur to sit in poor alignment and gives the illusion of one leg being shorter (while it really just isn't sitting the same as the other side). This displacement can also put pressure on nerves in the area and cause neurologic symptoms, including weakness.