Repeatability of gait data using a functional hip joint centre and a mean helical knee axis.

Area of Science:

• Biomechanics
• Human movement analysis
• Orthopedics

Background:

• Repeatability of kinematic and kinetic models is crucial for accurate gait analysis.
• Traditional models rely on precise anatomical landmark (AL) identification, which can be challenging and affect data consistency.
• Novel numerical methods independent of ALs may enhance the reliability of gait data.

Purpose of the Study:

• To compare the repeatability of gait data between an anatomical landmark (AL) based model and a functional (FUN) model.
• To evaluate the effectiveness of a foot calibration rig in defining the foot segment independently of ALs.
• To assess the influence of tester and session variations on model repeatability.

Main Methods:

• Developed and compared an AL model and a FUN model for gait analysis.
• The FUN model utilized a functional method for hip joint centers and a mean helical axis for knee joint axes.
• A foot calibration rig was used to define the foot segment in both models, independent of ALs.

Main Results:

• The FUN model demonstrated slightly superior repeatability for hip and knee kinematic and kinetic data compared to the AL model.
• Repeatability was consistent across within-tester and between-tester sessions for both models.
• The foot calibration rig provided a repeatable method for foot segment definition without requiring precise AL identification.

Conclusions:

• The FUN model offers improved repeatability in gait analysis and eliminates the need for accurate AL localization.
• The functional method and foot calibration rig are advantageous, particularly for populations where AL identification is difficult.
• Both models showed similar repeatability across different testing sessions, indicating robust methodologies.