ABSTRACT
Joint kinematics can vary substantially between individual subjects, and errors in joint definitions can have pronounced effects on the results of clinical gait analyses.
This variation in joint mechanics has motivated the development of “functional” methods, in which the locations of joint centers and joint axes are determined from the measured joint rotations rather than being defined relative to bony landmarks. Functional methods for location of the flexion axis of the knee
and the center of rotation of the hip
have been widely studied in research settings, and these methods are gaining acceptance in clinical laboratories. Evaluations of functional methods under controlled conditions suggest that they are more accurate, robust, and reproducible than methods that rely upon anatomical landmark location.
