This 2008 ANCHOR study group consensus paper establishes a standardized five-view plain radiographic protocol for the symptomatic young adult hip. It defines positioning requirements and quantitative thresholds for diagnosing acetabular dysplasia, femoroacetabular impingement, and early osteoarthritis. The goal is a reproducible framework that supports accurate diagnosis and surgical decision-making across providers.
Young adults with hip pain were frequently misdiagnosed or diagnosed late because no standardized radiographic framework existed — clinicians used different views, different measurements, and inconsistent thresholds.
This paper gives you a systematic checklist to run on every young hip film. Start by verifying pelvic positioning: coccyx aligned with symphysis, 1–3 cm gap. A tilted film invalidates version measurements and must be repeated.
Then work sequentially through: Tönnis angle, lateral CEA, anterior CEA on false-profile, crossover sign with posterior wall assessment, head sphericity on both AP and lateral, alpha angle, head-neck offset ratio, hip center lateralization, and Tönnis OA grade.
When you see a crossover sign, check the posterior wall before calling it retroversion. A crossover sign without posterior wall deficiency is anterior overcoverage. The surgical implications differ.
One pearl worth keeping: a femoral head can look perfectly round on AP pelvis and still carry a significant cam deformity visible only on the frog-leg or Dunn lateral. Always assess head-neck morphology on at least one lateral view before ruling out FAI.
This 2008 ANCHOR study group consensus paper establishes a standardized five-view plain radiographic protocol for the symptomatic young adult hip. It defines positioning requirements and quantitative thresholds for diagnosing acetabular dysplasia, femoroacetabular impingement, and early osteoarthritis. The goal is a reproducible framework that supports accurate diagnosis and surgical decision-making across providers.
Young adults with hip pain were frequently misdiagnosed or diagnosed late because no standardized radiographic framework existed — clinicians used different views, different measurements, and inconsistent thresholds.
This paper gives you a systematic checklist to run on every young hip film. Start by verifying pelvic positioning: coccyx aligned with symphysis, 1–3 cm gap. A tilted film invalidates version measurements and must be repeated.
Then work sequentially through: Tönnis angle, lateral CEA, anterior CEA on false-profile, crossover sign with posterior wall assessment, head sphericity on both AP and lateral, alpha angle, head-neck offset ratio, hip center lateralization, and Tönnis OA grade.
When you see a crossover sign, check the posterior wall before calling it retroversion. A crossover sign without posterior wall deficiency is anterior overcoverage. The surgical implications differ.
One pearl worth keeping: a femoral head can look perfectly round on AP pelvis and still carry a significant cam deformity visible only on the frog-leg or Dunn lateral. Always assess head-neck morphology on at least one lateral view before ruling out FAI.