Tibial Axis and Patellar Position Relative to the Femoral Epicondylar Axis during Squatting

Kathryn M. Coughlin, Stephen J. Incavo, David L. Churchill, Bruce D. Beynnon

Research output: Contribution to journalArticlepeer-review

81 Scopus citations


A laboratory-based study was performed to describe the tibial axis and patellar position relative to the femoral epicondylar (FE) axis during squatting. During the squat, the angle between the tibial and FE axes averaged 90.5°, and 66%, of internal rotation of the tibia occurred before 15° flexion. In the mid-sagittal plane of the femur, the patella followed a circular arc, and mediolateral patellar shift averaged 4.3 mm. These findings can be used as the basis for development of new total knee arthroplasty components that recreate normal patellofemoral kinematics, and may provide important guidelines for alignment of the tibial and femoral components. The perpendicular relationship between the tibial and the FE axes may be useful in locating the FE axis intraoperatively. The reduced mediolateral shift of the patella suggests that alignment of the femoral component with the FE axis will aid patellar tracking about a circular arc with small deviations in the medial-lateral direction.

Original languageEnglish (US)
Pages (from-to)1048-1055
Number of pages8
JournalJournal of Arthroplasty
Issue number8
StatePublished - Dec 2003


  • Alignment
  • Femoral epicondylar axis
  • Patella
  • Rotation
  • Tibia
  • Total knee arthroplasty

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Surgery


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