Scientific Articles   |    
Bone Apposition of the Acetabular Rim in Deep HipsA Distinct Finding of Global Pincer Impingement
Kristoff Corten, MD1; Reinhold Ganz, MD2; Etsuo Chosa, MD3; Michael Leunig, MD4
1 Department of Orthopaedic Surgery, University Hospital Pellenberg, Weligerveld 1, 3212 Pellenberg, Belgium
2 Department of Orthopaedic Surgery, University of Berne, 3010 Berne, Switzerland
3 Department of Orthopaedic Surgery, Faculty of Medicine, University of Miyazaki, 5200 Kihara Kiyotake Miyazaki, 889-1692, Japan
4 Department of Orthopaedic Surgery, Hip Service, Schulthess Clinic, Lengghalde 2, 8008 Zürich, Switzerland. E-mail address: Michael.leunig@kws.ch
View Disclosures and Other Information
Disclosure: The authors did not receive any outside funding or grants in support of their research for or preparation of this work. Neither they nor a member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity.

Investigation performed at Department of Orthopaedic Surgery, University of Berne, Berne, and Hip Service, Schulthess Clinic, Zürich, Switzerland

Copyright © 2011 by The Journal of Bone and Joint Surgery, Inc.
J Bone Joint Surg Am, 2011 May 04;93(Supplement 2):10-16. doi: 10.2106/JBJS.J.01799
5 Recommendations (Recommend) | 3 Comments | Saved by 3 Users Save Case



Hips with coxa profunda can develop a pincer-type impingement with linear impact between the proximal part of the femur and the acetabulum, leading to bone apposition on the acetabular rim.


Twenty hips with radiographic features of rim ossification were isolated from a pilot cohort of 220 patients for histologic assessment of the acetabular rim and the labrum. In the second part of the study, the prevalence of radiographic signs of bone apposition in a cohort of 148 hips treated for femoroacetabular impingement was assessed.


Histologic analysis confirmed that the labrum may become displaced and replaced by the appositional bone formation. The double-line sign and the recess sign are suggestive of an ongoing process of this bone formation, and the described phenotypes of bone apposition indicate the site of the impingement problem. Morphological anomalies of the proximal part of the femur, such as a low neck-shaft angle or a short femoral neck, may further contribute to the mechanism of pincer impingement.


In later stages, this bone formation cannot be distinguished from the native bone and the labrum may appear to be nearly absent on imaging studies. While the bone apposition on the rim is first reactive to chronic impingement, the impingement then increases and may lead to further bone apposition.

Figures in this Article
    Sign In to Your Personal ProfileSign In To Access Full Content
    Not a Subscriber?
    Get online access for 30 days for $35
    New to JBJS?
    Sign up for a full subscription to both the print and online editions
    Register for a FREE limited account to get full access to all CME activities, to comment on public articles, or to sign up for alerts.
    Register for a FREE limited account to get full access to all CME activities
    Have a subscription to the print edition?
    Current subscribers to The Journal of Bone & Joint Surgery in either the print or quarterly DVD formats receive free online access to JBJS.org.
    Forgot your password?
    Enter your username and email address. We'll send you a reminder to the email address on record.

    Forgot your username or need assistance? Please contact customer service at subs@jbjs.org. If your access is provided
    by your institution, please contact you librarian or administrator for username and password information. Institutional
    administrators, to reset your institution's master username or password, please contact subs@jbjs.org


    Accreditation Statement
    These activities have been planned and implemented in accordance with the Essential Areas and policies of the Accreditation Council for Continuing Medical Education (ACCME) through the joint sponsorship of the American Academy of Orthopaedic Surgeons and The Journal of Bone and Joint Surgery, Inc. The American Academy of Orthopaedic Surgeons is accredited by the ACCME to provide continuing medical education for physicians.
    CME Activities Associated with This Article
    Submit a Comment
    Please read the other comments before you post yours. Contributors must reveal any conflict of interest.
    Comments are moderated and will appear on the site at the discretion of JBJS editorial staff.

    * = Required Field
    (if multiple authors, separate names by comma)
    Example: John Doe

    Related Content
    The Journal of Bone & Joint Surgery
    JBJS Case Connector
    Topic Collections
    Related Audio and Videos
    Clinical Trials
    Readers of This Also Read...
    JBJS Jobs
    Pennsylvania - Penn State Milton S. Hershey Medical Center
    Ohio - OhioHealth Research and Innovation Institute (OHRI)
    Pennsylvania - Penn State Milton S. Hershey Medical Center