[Forces at the implant-bone interface of condylar knee prosthesis--with special reference to the retention of the posterior cruciate ligament].
Breakdown of the implant-bone interface is the most important factor limiting the effective life of total joint replacement. A particular example is the tibial component of the knee prosthesis which interfaces with trabecular bone. It is postulated that one of the major reasons for interface breakdown is excessive shear, compressive and moment stresses at the implant-bone interface. These stresses can be greatly influenced by the design of the prostheses, namely surface contour of the tibial component and the retention of the posterior cruciate ligament. Forces across the tibial component-bone interface was measured for prostheses both retaining and sacrificing the posterior cruciate ligament and for partially conforming and non-conforming, flat geometries. The results are as follows: Shear force, normal force and moment force across the interface were significantly greater for the prostheses sacrificing the posterior cruciate ligament than for those retaining it. Moment force was markedly greater for the tibial component with anterior curvature than for flat tibial component. It was suggested from this experiment that the knee prosthesis should retain the posterior cruciate ligament and the surface of the tibial component should probably be flatter for reducing the forces at the implant-bone interface.
D001696:Biomechanical Phenomena; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D007720:Knee Prosthesis; D008023:Ligaments, Articular / Q000502:physiology*; D013977:Tibia / Q000502:physiology