title: A morphometric study of normal and varus knees.
abstract: OBJECTIVE
  The aim of the study was to investigate varus and normal knee morphologies to identify differences that may affect knee replacement alignment or design for varus knees.
  
  
  METHODS
  Computed tomography scans of varus and normal knees were analyzed, and geometric shapes, points and axes were fit to the femur and tibia independently. These points were then projected in the three anatomical planes to measure the variations between the two groups.
  
  
  RESULTS
  In the femur, varus knees had less femoral anteversion (p < 0.0001) and a larger medial extension facet (p < 0.05) compared with normal knees. In the tibia, the tubercle was found to be externally rotated in varus knees (12°), with a significant increase in the coronal slope (p = 0.001) and the extension facet angle (p = 0.002).
  
  
  CONCLUSIONS
  The study highlighted the differences and similarities found between the two groups, which raises awareness on changes required during surgical intervention and component placement or design for a varus knee. This is particularly relevant for the design of patient-specific instrumentation and implants.
  
  
  METHODS
  Diagnostic study, Level III.
authors.affiliation: Department of Mechanical Engineering, City and Guilds Building, Imperial College London, London, SW7 2AZ, UK, pramod@imperial.ac.uk.
authors.forename: Pramod Kumar
authors.initials: PK
authors.lastname: Puthumanapully
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Harris
authors.forename: Anthony
authors.initials: A
authors.lastname: Leong
authors.forename: Justin P
authors.initials: JP
authors.lastname: Cobb
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Amis
authors.forename: Jonathan
authors.initials: J
authors.lastname: Jeffers
mesh_terms: D001696:Biomechanical Phenomena; D017760:Bone Malalignment / Q000000981:diagnostic imaging*; D005269:Femur / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging* / Q000502:physiology / Q000503:physiopathology; D008297:Male; D061330:Multidetector Computed Tomography; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging* / Q000503:physiopathology; D013977:Tibia / Q000000981:diagnostic imaging / Q000503:physiopathology