, Volume 470, Issue 8, pp 2274-2279
Date: 10 Apr 2012

Clinical Stability of Slipped Capital Femoral Epiphysis does not Correlate with Intraoperative Stability

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The most important objective of clinical classifications of slipped capital femoral epiphysis (SCFE) is to identify hips associated with a high risk of avascular necrosis (AVN) — so-called unstable or acute slips; however, closed surgery makes confirmation of physeal stability difficult. Performing the capital realignment procedure in SCFE treatment we observed that clinical estimation of physeal stability did not always correlate with intraoperative findings at open surgery. This motivated us to perform a systematic comparison of the clinical classification systems with the intraoperative observations.


We asked: (1) Is the classification of an acute versus chronic slip based on the duration of symptoms sensitive and specific in detecting intraoperative disrupted physes in patients with SCFE? (2) Is the stable/unstable classification system based on clinical symptoms sensitive and specific in detecting intraoperative disrupted physes in patients with SCFE?


We retrospectively reviewed 82 patients with SCFE treated by open surgery between 1996 and 2009. We classified the clinical stability of all hips using the classifications based on onset of symptoms and on function. We classified intraoperative stability as intact or disrupted. We determined the sensitivity and specificity of two classification systems to determine intraoperative stability.


Complete physeal disruption at open surgery was seen in 28 of the 82 hips (34%). With classification as acute, acute-on-chronic, and chronic, the sensitivity for disrupted physes was 82% and the specificity was 44%. With the classification of Loder et al., the values were 39% and 76%, respectively.


Current clinical classification systems are limited in accurately diagnosing the physeal stability in SCFE.

Level of Evidence

Level III, retrospective diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

Each author certifies that he or she, or a member of their immediate family, has no commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article.
All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request.
Each author certifies that his or her institution approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained.