International Orthopaedics

, Volume 29, Issue 3, pp 152–155 | Cite as

Peri-acetabular radiolucent lines: inter- and intra-observer agreement on post-operative radiographs

  • D. Kneif
  • M. Downing
  • G. P. AshcroftEmail author
  • P. Gibson
  • D. Knight
  • W. Ledingham
  • J. Hutchison
Original Paper


Peri-acetabular radiolucent lines (RLLs) seen on “early” post-operative radiographs have been identified as a potential predictor of long-term implant performance. This study examines the inter- and intra-observer variation encountered when assessing such radiographs. Four consultant orthopaedic surgeons assessed the presence, extent and width of RLLs in 220 radiographs performed on 50 patients taken one to two weeks, six weeks, six months and one year following surgery. Inter-observer agreement was fair at 7–14 days but improved to moderate to good in films at six and 12 months. Intra-observer agreement was moderate to good at 7–10 days but again improved to good at 6 and 12 months. When only the presence or absence of RLLs was considered, both inter-observer and intra-observer agreement improved for both the six-month and one-year radiographs. This experiment shows that caution must be used for the interpretation of RLLs on hip radiographs taken during the very early post-operative period. We recommend that films taken at least six weeks to six months following surgery should be used for assessment to reduce observer variation. For optimum results, a single experienced observer should do the assessment with a simple classification.


Radiolucent Line Nous Recommandons Cement Socket Obturator Oblique View Radiological Grade System 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Les liserés périacétabulaires (RLL) vu sur les radiographies postopératoires précoces ont été identifiés comme prédictifs de la performance de l’implant à long terme. Cette étude examine la variation inter-et intra-observateurs dans la lecture de telles radiographies. Quatre chirurgiens orthopédistes consultants ont étudié la présence, l’étendue et la largeur des liserés dans 220 radiographies exécutées chez 50 malades à deux semaines, six semaines, six mois et une année après la chirurgie. L’accord inter-observateurs était médiocre entre sept et quatorze jours, mais s’est amélioré dans les films plus tardifs à six et à douze mois. L’accord Intra-Observateur était modéré à bon à sept à dix jours mais encore amélioré à bon à six et douze mois. Quand seulement la présence ou l’absence de liserés ont été considérées, les deux études, inter-observateur et intra-observateur, ont amélioré les radiographies de six mois et d’une année. Cette expérience montre que la prudence doit être utilisée pour l’interprétation des liserés sur des radiographies de la hanche prises précocement pendant la période postopératoire. Nous recommandons que les radiographies prises six semaines à 6 mois après la chirurgie soient utilisé pour l’estimation, en réduisant la variation de l’observateur. Pour les résultats optimum un observateur expérimenté seul devrait faire l’estimation avec une classification simple.



We wish to acknowledge the Arthritis an Rheumatism Council who funded the RSA study and Johnson and Johnson and Howmedica/ Stryker Ltd. for continuing support. We also wish to thank our audit nurses Mrs. Ann Suttcliffe and Miss Ann Potter and our radiographers in the Woodend Orthopaedic Department.


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Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • D. Kneif
    • 1
  • M. Downing
    • 1
  • G. P. Ashcroft
    • 1
    • 3
    Email author
  • P. Gibson
    • 2
  • D. Knight
    • 2
  • W. Ledingham
    • 2
  • J. Hutchison
    • 1
  1. 1.Department of OrthopaedicsAberdeen UniversityAberdeenUK
  2. 2.Department of OrthopaedicsAberdeen University Hospital TrustAberdeenUK
  3. 3.Department of OrthopaedicsAberdeen Medical SchoolAberdeenUK

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