title: A novel 3D approach for determination of frontal and coronal plane tibial slopes from MR imaging.
abstract: BACKGROUND
  The proximal tibia is geometrically complex, asymmetrical, and variable, is heavily implicated in arthrokinematics of the knee joint, and thus a contributor to knee pathologies such as non-contact anterior cruciate ligament injury. Medial, lateral, and coronal tibial slopes are anatomic parameters that may increase predisposition to knee injuries, but the extent to which each contributes has yet to be fully realized. Previously, two-dimensional methods have quantified tibial slopes, but more reliable 3D methods may prove advantageous.
  
  
  OBJECTIVE
  (1) to explore the reliability of two-dimensional methods, (2) to introduce a novel three-dimensional measurement approach, and (3) to compare data derived from traditional and novel methods.
  
  
  METHODS
  Medial, lateral, and coronal tibial slope geometry from both knees (left and right) of one subject were obtained via magnetic resonance images and measured by four trained observers from two-dimensional views. The process was repeated via three-dimensional approaches and data evaluated for intra- and inter-rater reliability.
  
  
  RESULTS
  The conventional method presented a weaker Intraclass Correlation Coefficient (ICC) for the measured slopes (ranging from 0.43 to 0.81) while the resultant ICC for the proposed method indicated greater reliability (ranging from 0.84 to 0.97). Statistical analysis supported the novel approach for production of more reliable and repeatable results for tibial slopes.
  
  
  CONCLUSIONS
  The novel three-dimensional method for calculating tibial plateau slope may be more reliable than previously established methods and may be applicable in assessment of susceptibility to osteoarthritis, as part of anterior cruciate ligament injury risk assessment, and in total knee implant design.
authors.affiliation: Engineering Center for Orthopaedic Research Excellence (ECORE), Departments of Bioengineering and Orthopaedic Surgery, Colleges of Engineering and Medicine, The University of Toledo, 2801 W. Bancroft Street, Toledo, OH 43606, USA.
authors.forename: Amirhesam
authors.initials: A
authors.lastname: Amerinatanzi
authors.affiliation: Engineering Center for Orthopaedic Research Excellence (ECORE), Departments of Bioengineering and Orthopaedic Surgery, Colleges of Engineering and Medicine, The University of Toledo, 2801 W. Bancroft Street, Toledo, OH 43606, USA.
authors.forename: Rodney
authors.initials: R
authors.lastname: Summers
authors.affiliation: Engineering Center for Orthopaedic Research Excellence (ECORE), Departments of Bioengineering and Orthopaedic Surgery, Colleges of Engineering and Medicine, The University of Toledo, 2801 W. Bancroft Street, Toledo, OH 43606, USA.
authors.forename: Kaveh
authors.initials: K
authors.lastname: Ahmadi
authors.affiliation: Engineering Center for Orthopaedic Research Excellence (ECORE), Departments of Bioengineering and Orthopaedic Surgery, Colleges of Engineering and Medicine, The University of Toledo, 2801 W. Bancroft Street, Toledo, OH 43606, USA.
authors.forename: Vijay K
authors.initials: VK
authors.lastname: Goel
authors.affiliation: Mayo Clinic Biomechanics Laboratory, Department of Orthopedic Surgery, Department of Physiology & Biomedical Engineering, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA; Mayo Clinic Sports Medicine Center, Department of Orthopedic Surgery, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Hewett
authors.affiliation: Engineering Center for Orthopaedic Research Excellence (ECORE), Departments of Bioengineering and Orthopaedic Surgery, Colleges of Engineering and Medicine, The University of Toledo, 2801 W. Bancroft Street, Toledo, OH 43606, USA; College of Health Professions, The University of Findlay, 1000 N. Main Street, Findlay, OH 45840, USA. Electronic address: nyman@findlay.edu.
authors.forename: Edward
authors.initials: E
authors.lastname: Nyman
mesh_terms: D000070598:Anterior Cruciate Ligament Injuries / Q000601:surgery*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007718:Knee Injuries; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015203:Reproducibility of Results; D013977:Tibia / Q000000981:diagnostic imaging*
keywords: ACL; Imaging; Knee; Tibial slope