Lateral center-edge angle
The lateral center-edge angle is a radiographic measurement of femoral head bony coverage by the acetabulum. It has primarily been described in assessing for acetabular dysplasia but can also be used in femoroacetabular impingement.
It is calculated on AP pelvic radiographs by using drawing a best fit circle for the inferior and medial margins femoral head. The angle is then measured between two lines drawn from the center of the circle, one running vertically along the longitudinal axis of the pelvis and the other to the acetabular sourcil edge.
Values greater than 20 degrees but less than 40 degrees are considered within the normal range 1.
Increased lateral center-edge angle
- pincer type impingement
Reduced lateral center-edge angle
- acetabular dysplasia
- cannot be measured in patients with abnormal femoral heads due to previous injury or avascular necrosis
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