Scientific Articles   |    
Contribution of Articular Surface Geometry to Ankle Stabilization
Yuki Tochigi, MD, PhD1; M. James Rudert, PhD1; Charles L. Saltzman, MD2; Annunziato Amendola, MD3; Thomas D. Brown, PhD1
1 Orthopaedic Biomechanics Laboratory, University of Iowa, 2181 Westlawn, Iowa City, IA 52242-1100. E-mail address for Y. Tochigi: yuki-tochigi@uiowa.edu
2 Orthopaedic Center, University of Utah, 590 Wakara Way, Salt Lake City, UT 84108
3 Department of Orthopaedics and Rehabilitation, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, Iowa City, IA 52242
View Disclosures and Other Information
In support of their research for or preparation of this manuscript, one or more of the authors received grants or outside funding from the American Orthopaedic Foot and Ankle Society, the Chiba University Orthopaedic Alumni Foundation, and the National Institutes of Health (Grant P50 AR048939.) None of the authors received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the authors are affiliated or associated.
Investigation performed at the Department of Orthopaedics and Rehabilitation, University of Iowa, Iowa City, Iowa

The Journal of Bone and Joint Surgery, Incorporated
J Bone Joint Surg Am, 2006 Dec 01;88(12):2704-2713. doi: 10.2106/JBJS.E.00758
5 Recommendations (Recommend) | 3 Comments | Saved by 3 Users Save Case


Background: Passive ankle stability under weight-bearing conditions has been found to depend substantially on the role of the articular surface geometry. In the present study, it was hypothesized that, in the ankle under axial loading, contact-stress changes in response to alterations of external load involve reproducible and specific patterns to maintain ankle stability.

Methods: Six cadaver ankles with the peri-ankle ligaments intact were tested. Each specimen, held at several predetermined ankle positions under a primary one-body-weight axial force, was subjected to an additional secondary load. The secondary load—specifically, anterior/posterior shear force, inversion/eversion torque, or internal/external rotation torque—was applied independently, while motion associated with the two other secondary loading directions was unconstrained. Contact stress in the tibiotalar articulation was monitored by a real-time contact-stress sensor. Site-specific stress changes solely due to secondary loading at each load/position were identified by subtraction of the corresponding axial-force-only baseline distribution. The role of these stress changes in ankle stabilization was studied for each specimen by analyzing the data with a computer model of ankle geometry.

Results: In the cadaver experiment, anterior and posterior shear forces caused reproducible positive changes in articular contact stresses on the anterior and posterior regions, respectively. Similar changes with version torques occurred on the medial and lateral regions. Positive changes with internal/external rotation torques occurred at two diagonal locations: anterolateral and posteromedial, or anteromedial and posterolateral. In the model analysis, these stress-change patterns were found to be effective in ankle stabilization, and the levels of contribution by the articular surface were calculated as accounting for approximately 70% of anterior/posterior stability, 50% of version stability, and 30% of internal/external rotation stability.

Conclusions: The documented changes in contact stress illustrate the major role of articular geometry in passive ankle stabilization. The levels of contribution by the articular surface that we calculated are consistent with those reported in the literature. These findings support the conceptual mechanism of ankle stabilization by redistribution of articular contact stress.

Clinical Relevance: Passive ankle stability under weight-bearing conditions appears to be dictated by the integrity of articular surface geometry, implying that any abnormality of that geometry can affect joint kinematics during locomotive activities.

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
    PubMed Articles
    Clinical Trials
    Readers of This Also Read...
    JBJS Jobs
    New York - Icahn School of Medicine at Mount Sinai
    S. Carolina - Department of Orthopaedic Surgery Medical Univerity of South Carlonina
    W. Virginia - Charleston Area Medical Center