A technique for quantitative assessment of three-dimensional motion with applications to human joints.

A technique is developed for quantitative measurement of general three-dimensional motion, and this technique is applied to the kinematics of anatomical joints. The spatial locations of three orthogonal points representing coordinate frames on each member of the joint are measured during motion of the joint by photo encoders of a three-dimensional mechanical pointer. Kinematic calculations are used to derive, from the experimentally collected data, the six orthogonal components of the motion of one member relative to the other. The accuracy of this technique is presented. Applications to the knee and ankle are discussed.