A systematic approach to the plain radiographic evaluation of the young adult hip.

Introduction rthopaedic evaluation of hip pain in the young adult population has undergone a rapid evolution over the past decade. This is in large part due to enhanced awareness of structural hip disorders, including developmental dysplasia of the hip and femoroacetabular impingement. Surgical treatment for these disorders continues to be refined, and our ability to identify patients along the spectrum of disease continues to improve. Yet, despite our advances, obtaining an accurate diagnosis can remain challenging, especially in the setting of mild structural abnormalities. Therefore, radiographic examination is a critical component of the diagnostic evaluation and treatment decision-making process. It is essential that physicians have common and reliable radiographic views as well as parameters for plain radiographic assessment that can serve as a foundation for accurate diagnosis, disease classification, and surgical decision-making. Many different radiographic measurements have been described as indicators of structural disease. In particular, measurements such as the lateral center-edge angle of Wiberg, the anterior center-edge angle of Lequesne, the acetabular index of depth to width described by Heyman and Herndon, the femoral head extrusion index, and the Tönnis angle have been used as markers for acetabular dysplasia. Similarly, measurements of acetabular version, the headneck offset (initially described by Eijer), and the alpha angle have been used in the diagnosis of femoroacetabular impingement. Nevertheless, there is limited literature that provides comprehensive information regarding the details of radiographic evaluation in the young patient with hip symptoms. This paper summarizes the recommendations of the ANCHOR (Academic Network for Conservational Hip Outcomes Research) study group regarding the most important aspects of radiographic technique and image interpretation to evaluate the symptomatic, skeletally mature hip.