Radiographic evaluation of the hip has limited reliability

Clin Orthop Relat Res. 2009 Mar;467(3):666-75. doi: 10.1007/s11999-008-0626-4. Epub 2008 Dec 2.


Radiographic evaluation provides essential information regarding the diagnosis and treatment of musculoskeletal disorders. We evaluated the ability of hip specialists to reliably identify important radiographic features and to make a diagnosis based on plain radiographs alone. Five hip specialists and one fellow performed a blinded radiographic review of 25 control hips, 25 hips with developmental dysplasia (DDH), and 27 with femoroacetabular impingement (FAI). On two separate occasions, readers assessed acetabular version, inclination and depth, position of the femoral head center, head sphericity, head-neck offset, Tönnis grade, and joint congruency. Observers made a diagnosis categorizing each hip as normal, dysplastic, FAI, or combined DDH and FAI (features of both). Reliability was determined using Cohen's kappa coefficient. Intraobserver values were highest for acetabular inclination (kappa = 0.72) and determination of femoral head center position (kappa = 0.77). Interobserver reliability values were highest for acetabular inclination (kappa = 0.61) and Tönnis osteoarthritis grade (kappa = 0.59). All other measurements, including diagnosis, had kappa values less than 0.55. We concluded many of the standard radiographic parameters used to diagnose DDH and/or FAI are not reproducible. Accordingly, a more clear set of definitions and measurements must be developed to allow for more reliable diagnosis of early hip disease.

Publication types

  • Evaluation Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Acetabulum / diagnostic imaging*
  • Acetabulum / physiopathology
  • Arthrography*
  • Early Diagnosis
  • Femur / diagnostic imaging*
  • Femur / physiopathology
  • Hip Dislocation, Congenital / diagnostic imaging*
  • Hip Dislocation, Congenital / physiopathology
  • Hip Joint / diagnostic imaging*
  • Hip Joint / physiopathology
  • Humans
  • Observer Variation
  • Predictive Value of Tests
  • Range of Motion, Articular
  • Reproducibility of Results
  • Retrospective Studies
  • Severity of Illness Index