Three dimensional design optimization of femoral components of total hip endoprostheses.

摘要

It was the subject of this study to investigate the use of numerical optimization techniques for the 3-D shape and material design of total hip joint replacement, and to provide general design guidelines on some design aspects of femoral components.; A modular program was developed to interface the DOT and DOC optimization routines coupled with ABAQUS finite element code with implant surface generator and composite analyzer to perform design optimization of the boundary of implant and fiber-reinforced composite design of the prostheses.; An internal parametric representation technique based on Bezier interpolation curves and super-ellipses was developed to generate the implant surface as a 3-D object. Two basic loading cases, pure moment and physiological loads were used.; In the case of perfectly bonded, cemented and noncemented THA, failure-based objective functions have been used to reduce the risk of interface loosening, and in press-fitted models with frictional interface the design objective was minimization of relative slip. In both cases optimization produced a considerable amount of reduction in bone stresses and more uniform load transfer in the vicinity of the interface. Certain trends were observed, regardless of the loading case or the choice of objective functions.; The potential for adaptive remodeling was another design objective which has been used in shape and material optimization of the noncemented perfectly bonded THA. A multicriteria objective function was proposed to combine a failure-based criteria and a remodeling-based function. The results demonstrated the competing nature of remodeling-based and failure-based objective functions.; The overall results of the study indicate the effectiveness of the optimization technique as a design tool which can provide meaningful insight into the design of the femoral component of prostheses.