Best Practice Case Studies-Case 134 Asset 4 A Systematic Approach to Hip Radiographs

Case 134 Asset 4 A Systematic Approach to Hip Radiographs

Pdf Summary

This article presents a systematic method for evaluating the symptomatic young adult hip using plain radiographs. It emphasizes that accurate diagnosis of structural hip disorders—especially developmental dysplasia of the hip and femoroacetabular impingement—depends on standardized imaging technique and careful interpretation of multiple views.<br /><br />The recommended radiographic set includes an anteroposterior (AP) pelvic view, cross-table lateral, 45° or 90° Dunn view, frog-leg lateral, and false-profile view. The paper details proper patient positioning, beam angle, and source-to-film distance for each projection, noting that small positioning errors can significantly affect diagnostic accuracy. On the AP pelvis, the authors stress checking pelvic tilt and rotation using landmarks such as the coccyx, pubic symphysis, iliac wings, obturator foramina, and teardrops.<br /><br />For interpretation, the article outlines key measurements and signs. These include acetabular depth (coxa profunda, protrusio acetabuli), acetabular inclination using the Tönnis angle, lateral center-edge angle, anterior center-edge angle, and acetabular version using the crossover sign and ischial spine projection. It also describes assessment of femoral head sphericity, hip center lateralization, and head-neck offset abnormalities, including the alpha angle and head-neck offset ratio, which help identify cam-type impingement. Joint congruency and the Tönnis grade are used to assess osteoarthritis severity.<br /><br />Overall, the article argues that a structured, reproducible radiographic approach improves recognition of hip morphology, supports classification of disease, and aids surgical decision-making. It also notes that radiographs should always be interpreted in the context of history, physical examination, and, when needed, advanced imaging.

Keywords

young adult hip

plain radiographs

developmental dysplasia

femoroacetabular impingement

AP pelvis

Dunn view

false-profile view

Tönnis angle

alpha angle

acetabular version