RESUMEN
A sagittal plane model of knee joint based on crossed-four-bar-linkage-based tibiofemoral joint model has been developed using geometric and force equilibrium constraints. The model predicts and explains the movement of contact point on the patella and femur, variation of patellar and patellar tendon angle, variation of patellar mechanism angle and variation of patellofemoral contact force and patellar tendon force. The computed results agree well with the published experimental results.
Asunto(s)
Humanos , Fenómenos Biomecánicos , Articulación de la Rodilla , Fisiología , Modelos Biológicos , Movimiento , Fisiología , Rótula , FisiologíaRESUMEN
Resorption and osteolysis of periimplant bones resulting from the wear debris of artificial joint will cause long-term loosening. A new type of rolling knee artificial joint without UHMWPE based on the mechanics of rolling friction is designed for alleviating this problem. Because of low friction force, the resistance of extension and flexion is reduced strikingly and the stress on the interface between prosthesis and bone is reduced evidently. In addition, the bio-toxicity caused by the wear debris of UHMWPE will not occur absolutely. In consequence, the rolling artificial joint can prevent the trend of long-term loosening of the prosthesis efficiently.
Asunto(s)
Animales , Perros , Humanos , Artroplastia de Reemplazo de Rodilla , Cerámica , Química , Diseño Asistido por Computadora , Prótesis de la Rodilla , Ensayo de Materiales , Polietilenos , Diseño de Prótesis , Vitalio , QuímicaRESUMEN
The mechanical model of knee is a system of constructional elements with specific restrains and material properties, which are deduced from the components of knee based on their functions and junctions. Kinematics and kinetics of knee can be calculated from the mechanical model. A review of some mechanical models of knee are shown in this paper.
Asunto(s)
Humanos , Fenómenos Biomecánicos , Simulación por Computador , Articulación de la Rodilla , Fisiología , Modelos Biológicos , Rango del Movimiento Articular , Fisiología , Estrés MecánicoRESUMEN
A novel method for the design of hip joint prostheses based on X-ray films is introduced. Only arcs and straight-lines form figures of hip joint prostheses. Because geometrical tolerances of manufacturing hip joint prostheses matching section are usually not strict, hip joint prostheses can be manufactured without CNC machine tool. Three hip joint prostheses for three different femurs were designed through a program which was developed by the present authors. Approximate marrow cavities of these femurs were simulated according to a standard database about femur. These models of femur marrow cavities were used to verify the hip joint prostheses designed. These hip joint prostheses designed were manufactured and implanted into femurs respectively. Experimental results indicate that the novel method for the design of hip joint prostheses is practicable.