The Journal of Bone and Joint Surgery (American). 2008;90:2452-2459.
doi:10.2106/JBJS.G.01230
© 2008 The Journal of Bone and Joint Surgery, Inc.
Accessory Anterolateral Facet of the Pediatric TalusAn Anatomic Study
Jeffrey E. Martus, MD1,
John E. Femino, MD2,
Michelle S. Caird, MD3,
Richard E. Hughes, PhD3,
Richard H. Browne, PhD4 and
Frances A. Farley, MD3
1 Department of Orthopaedics and Rehabilitation, Vanderbilt University, 2200 Children's Way, 4202 DOT, Nashville, TN 37232-9565. E-mail address: jeff.martus{at}vanderbilt.edu
2 Department of Orthopaedic Surgery, University of Iowa Medical Center, 200 Hawkins Drive, Iowa City, IA 52242. E-mail address: john-femino{at}uiowa.edu
3 Department of Orthopaedic Surgery, University of Michigan Medical Center, TC 2912, 1500 East Medical Center Drive, Ann Arbor, MI 48109-0328
4 Department of Orthopaedic Surgery, Texas Scottish Rite Hospital for Children, 2222 Welborn Street, Dallas, TX 75219
Investigation performed at The University of Michigan, Ann Arbor, Michigan
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. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, division, center, clinical practice, or other charitable or nonprofit organization with which the authors, or a member of their immediate families, are affiliated or associated.
Background: The accessory anterolateral talar facet may be associated with talocalcaneal impingement in the painful flatfoot. We performed an anatomic study to identify this accessory facet and its associated osteologic features.
Methods: Within the Hamann-Todd Human Osteological Collection, seventy-nine paired tali and calcanei were identified among forty-three skeletons from individuals who had had an average age of 13.4 years at the time of death. Each specimen was surveyed for an accessory anterolateral talar facet, a calcaneal neck anterior extension facet, a dorsal talar beak, and the talocalcaneal facet pattern. Measurements included the angle of Gissane, posterior facet inclination, calcaneal neck length, posterior facet length, overall calcaneal and talar lengths, and accessory facet dimensions. Lateral radiographs of specimens with accessory facets were made in neutral and everted subtalar alignment.
Results: An accessory anterolateral talar facet was identified in twenty-seven (34%) of the seventy-nine specimens and was large in two (2.5%). Of the thirty-six skeletons with paired specimens, fifteen had an accessory facet and, of those, ten had the finding bilaterally. Degenerative changes or tarsal coalitions were not observed. Lateral radiographs demonstrated that subtalar eversion obscured observation of the facet. The accessory facet was associated with greater mean age (16.7 compared with 10.9 years; p < 0.0001), male sex (63% compared with 21%; p = 0.011), and a smaller mean angle of Gissane (116.2° compared with 122.2°; p = 0.018). Relative accessory facet volume was positively correlated with increased relative calcaneal posterior facet length (r = 0.53, p = 0.029). The accessory facet was significantly associated with dorsal talar beaking (29% compared with 4%; p = 0.028).
Conclusions: An accessory anterolateral talar facet was found in 34% of the specimens in a pediatric osteologic collection. The facet was associated with male sex, a smaller angle of Gissane, and dorsal talar beaking.
Clinical Relevance: Dorsal talar beaking may indicate the presence of an accessory anterolateral talar facet. Identification of the facet may require cross-sectional imaging as lateral radiographs made with the subtalar joint everted may not demonstrate the anomaly.

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