Abstract:

The paper presents the validation of a methodology for the optimal positioning of a planar mechanical system in order to reproduce knee kinematics in a limited range of motion. Such a mechanism could be effectively used in the design and placement of a moving external fixator for the knee joint articulation in either post-traumatic or pathological treatment and rehabilitation. The purpose is to help patient’s recovery through a limited and occasional movement of the articulation without loading the injured area. In order to validate the actual method, knee kinematics is estimated by measuring flexo- extension on an Endo Leg Flyer with Navi-Robot, a passively self balanced 6 DOF Navigator able to turn into a Robot of our design and construction. Optimal positioning is obtained via least square methods minimization in which the error function has been evaluated imposing as constraint the possibility of pulling gently the ligament never allowing cartilage compression.

Keywords: kinematic optimization; knee motion; external fixator.