Minimization of the gliding index: criterion for the generation of the surfaces of a knee endoprosthesis.
Previous studies on removed failed artificial knees revealed significant degradation of the articular surfaces, including pitting and shredding, as well as burnishing accompanied by score marks and scratches, the latter damage group being related to the gliding motion of the joint. In an attempt to introduce an improved version of an artificial knee joint, we have proposed a general model by which the opposing surfaces of the prosthesis components can be synthesized. The criterion applied was that of minimization of a defined gliding index. The femoral condyles in this model were expressed in terms of torus geometry, and the kinematics of motion fed into the model was that of normal motion in the sagittal plane, including angles as well as the displacement vector in the knee joint. Geometry of the tibial component was obtained from the tangents of the femoral surface, in subsequent positions of motion. The optimal surfaces were those for which the gliding index assumed a minimal value. The solutions obtained for various input motions are presented and discussed.
Mizrahi
J
J
Department of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa.
Benaim
E
E
D001696:Biomechanical Phenomena; D005684:Gait; D006801:Humans; D007720:Knee Prosthesis; D008433:Mathematics; D011474:Prosthesis Design