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.
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 2. If abnormal:
- increased: pincer-type impingement
- decreased: acetabular dysplasia
History and etymology
It was first described by Lequesne and de Seze in 1961 1.
- 1. Lequesne M, de Seze S. Le faux profil du bassin: nouvelle incidence radiographique pour l’´etude de la hanche. Son utilit´e dans les dysplasies et les differentes coxopathies. Rev Rhum 1961;28:643-52.
- 2. Imai H, Kamada T, Takeba J, Shiraishi Y, Mashima N, Miura H. Anterior coverage after eccentric rotational acetabular osteotomy for the treatment of developmental dysplasia of the hip. (2014) Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association. 19 (5): 762-9. doi:10.1007/s00776-014-0592-5 - Pubmed