Anterior center-edge angle

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The anterior center-edge angle, also known as the vertical-center-anterior (VCA) angle, is a radiographic measurement of the anterior coverage of the femoral head by the acetabulum. It is used in assessing acetabular dysplasia and pincer type of femoroacetabular impingement.

Radiographic features

Plain radiograph

It is measured in the false profile view of the hip joint. The angle is measured between a vertical line through the center of the femoral head (line VC) and a second line from the center of the hip to the anterior-most aspect of the acetabulum (line CA).

Values from 20-45 degrees are considered to be within the normal range . If abnormal:

  • increased: pincer-type impingement
  • decreased: acetabular dysplasia

History and etymology

It was first described by Lequesne and de Sezein 1961 .