Three-dimensional patellar motion at the natural knee during passive flexion/extension. An in vitro study

Claudio Belvedere, Alberto Leardini, Andrea Ensini, Luca Bianchi, Fabio Catani, Sandro Giannini

Research output: Contribution to journalArticlepeer-review


Patellar maltracking may result in many patellofemoral joint (PFJ) disorders in the natural and replaced knee. The literature providing quantitative reference for normal PFJ kinematics according to which patellar maltracking could be identified is still limited. The aim of this study was to measure in vitro accurately all six-degrees-of-freedom of patellar motion with respect to the femur and tibia on 20 normal specimens.Astate-of-the-art knee navigation system, suitably adapted for this study aim, was used. Anatomical reference frames were defined for the femur, tibia, and patella according to international recommendations. PFJ flexion, tilt, rotation, and translations were calculated in addition to standard tibiofemoral joint (TFJ) kinematics. All motion patterns were found to be generally repeatable intra-/ interspecimens. PFJ flexion was 62% of the corresponding TFJ flexion range; tilt and translations along femoral mediolateral and tibial proximodistal axes during TFJ flexion were found with medial, lateral, and distal trends and within 12°, 6 and 9 mm, respectively. No clear pattern for PFJ rotation was observed. These results concur with comparable reports from the literature and contribute to the controversial knowledge on normal PFJ kinematics. Their consistence provides fundamental information to understand orthopedic treatment of the knee and for possible relevant measurements intraoperatively.

Original languageEnglish
Pages (from-to)1426-1431
Number of pages6
JournalJournal of Orthopaedic Research
Issue number11
Publication statusPublished - Nov 2009


  • Knee biomechanics
  • Patellar tracking
  • Patellofemoral joint kinematics
  • Tibiofemoral joint kinematics

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine


Dive into the research topics of 'Three-dimensional patellar motion at the natural knee during passive flexion/extension. An in vitro study'. Together they form a unique fingerprint.

Cite this