The Anteroposterior Pelvic Radiograph: Acetabular and Femoral Measurements and Relation to Hip Pathologies.

Abstract

➤ A proper technique is critically important for accurate interpretation of the anteroposterior radiograph, with a true anteroposterior radiograph of the pelvis made with the patient in the supine or standing position with a tube-to-image distance of 120 cm and a photon beam centered midway between the pubic symphysis and the top of the iliac crests.➤ Frequent characteristics of developmental dysplasia that may be seen on an anteroposterior pelvic radiograph are a hypoplastic acetabular weight-bearing zone, steeply sloped acetabular roof, lateralized center of rotation, acetabular anteversion or retroversion in the presence of a hypovolemic acetabulum, and coxa valga.➤ Increased depth, femoral head overcoverage, and/or abnormal acetabular version (typically retroversion) are the main etiologies of pincer-type femoroacetabular impingement (FAI).➤ Cam-type FAI deformities are represented by global deformities such as femoral head asphericity and diminished head-neck offset.➤ Commonly utilized grading systems of osteoarthritis evaluate the hip for evidence of joint-space narrowing, subchondral sclerosis and cyst formation, osteophyte development, and femoral head deformity.