Comparison of three formal methods used to estimate the functional axis of rotation: an extensive in-vivo analysis performed on the knee joint

Francesca Colle, Nicola Lopomo, Andrea Visani, Stefano Zaffagnini, Maurilio Marcacci

Research output: Contribution to journalArticle


Estimating the main axis of rotation (AoR) of a human joint represents an important issue in biomechanics. This study compared three formal methods used to estimate functional AoR, namely a cylindrical fitting method, a mean helical axis transformation, and a symmetrical axis approach. These methods were tested on 106 subjects undergoing navigated total knee arthroplasty. AoR orientation in 3D and in the frontal and coronal planes provided by each method was compared to the transepicondylar axis direction. Although all the methods resulted effective, significant differences were identified among them, relatively to the orientation in 3D and in the frontal plane projection. This was probably due to the presence of secondary rotations during the first degrees of knee flexion.

Original languageEnglish
Pages (from-to)484-492
Number of pages9
JournalComputer Methods in Biomechanics and Biomedical Engineering
Issue number5
Publication statusPublished - Apr 3 2016



  • cylindrical fitting method
  • functional axis
  • knee kinematics
  • mean helical axis
  • navigated TKA
  • symmetrical axis approach

ASJC Scopus subject areas

  • Bioengineering
  • Biomedical Engineering
  • Computer Science Applications
  • Human-Computer Interaction

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