title: Quantitative comparison of cortical bone thickness using correspondence-based shape modeling in patients with cam femoroacetabular impingement.
abstract: The proximal femur is abnormally shaped in patients with cam-type femoroacetabular impingement (FAI). Impingement may elicit bone remodeling at the proximal femur, causing increases in cortical bone thickness. We used correspondence-based shape modeling to quantify and compare cortical thickness between cam patients and controls for the location of the cam lesion and the proximal femur. Computed tomography images were segmented for 45 controls and 28 cam-type FAI patients. The segmentations were input to a correspondence-based shape model to identify the region of the cam lesion. Median cortical thickness data over the region of the cam lesion and the proximal femur were compared between mixed-gender and gender-specific groups. Median [interquartile range] thickness was significantly greater in FAI patients than controls in the cam lesion (1.47 [0.64] vs. 1.13 [0.22] mm, respectively; p < 0.001) and proximal femur (1.28 [0.30] vs. 0.97 [0.22] mm, respectively; p < 0.001). Maximum thickness in the region of the cam lesion was more anterior and less lateral (p < 0.001) in FAI patients. Male FAI patients had increased thickness compared to male controls in the cam lesion (1.47 [0.72] vs. 1.10 [0.19] mm, respectively; p < 0.001) and proximal femur (1.25 [0.29] vs. 0.94 [0.17] mm, respectively; p < 0.001). Thickness was not significantly different between male and female controls.
  
  
  
  Studies of non-pathologic cadavers have provided guidelines regarding safe surgical resection depth for FAI patients. However, our results suggest impingement induces cortical thickening in cam patients, which may strengthen the proximal femur. Thus, these previously established guidelines may be too conservative. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1743-1753, 2017.
authors: Department of Bioengineering, University of Utah, Salt Lake City, Utah, 84112.|Department of Orthopaedics, University of Utah, 590 Wakara Way Rm A100, Salt Lake City, Utah, 84108.
authors: Penny R
authors: PR
authors: Atkins
authors: Scientific Computing and Imaging Institute, Salt Lake City, Utah, 84112.|School of Computing, University of Utah, Salt Lake City, Utah, 84112.
authors: Shireen Y
authors: SY
authors: Elhabian
authors: Scientific Computing and Imaging Institute, Salt Lake City, Utah, 84112.|School of Computing, University of Utah, Salt Lake City, Utah, 84112.
authors: Praful
authors: P
authors: Agrawal
authors: Program of Physical Therapy, Washington University School of Medicine, Saint Louis, Missouri, 63110.|Department of Orthopaedic Surgery, Washington University School of Medicine, Saint Louis, Missouri, 63110.
authors: Michael D
authors: MD
authors: Harris
authors: Department of Bioengineering, University of Utah, Salt Lake City, Utah, 84112.|Scientific Computing and Imaging Institute, Salt Lake City, Utah, 84112.|School of Computing, University of Utah, Salt Lake City, Utah, 84112.
authors: Ross T
authors: RT
authors: Whitaker
authors: Department of Bioengineering, University of Utah, Salt Lake City, Utah, 84112.|Department of Orthopaedics, University of Utah, 590 Wakara Way Rm A100, Salt Lake City, Utah, 84108.|Scientific Computing and Imaging Institute, Salt Lake City, Utah, 84112.|School of Computing, University of Utah, Salt Lake City, Utah, 84112.
authors: Jeffrey A
authors: JA
authors: Weiss
authors: Department of Bioengineering, University of Utah, Salt Lake City, Utah, 84112.|Department of Orthopaedics, University of Utah, 590 Wakara Way Rm A100, Salt Lake City, Utah, 84108.
authors: Christopher L
authors: CL
authors: Peters
authors: Department of Bioengineering, University of Utah, Salt Lake City, Utah, 84112.|Department of Orthopaedics, University of Utah, 590 Wakara Way Rm A100, Salt Lake City, Utah, 84108.|Scientific Computing and Imaging Institute, Salt Lake City, Utah, 84112.|Department of Physical Therapy, University of Utah, Salt Lake City, Utah, 84108.
authors: Andrew E
authors: AE
authors: Anderson
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D054893:Cone-Beam Computed Tomography; D000071538:Cortical Bone / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D057925:Femoracetabular Impingement / Q000000981:diagnostic imaging / Q000473:pathology*; D005269:Femur / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D055815:Young Adult
keywords: FAI and morphology; bone; disease process; statistics