Study of optimized hip implant development for hip implant in total hip replacement

Abstract

A hip implant re-operation is usually related to the service life of the component, as determined by its material properties, or a loosening of the hip implant resulting from a poor alignment with adjacent bone tissues. These issues invariably arise from the use of standardized products even though each patient differs in terms of anatomical parameters of their hips. To deal with such challenges, customized hip implants are needed that are designed to optimize the alignment with the hip according to the anatomical differences of individual patients. Therefore, this study presents an optimal joint restoration system optimized to the needs of the individual user as regards developing treatment technology to restore the function of an aged joint. A hip implant usually consists of a body and neck, thus, among 15 anatomical basic parameters of the human femur, 8 are selected as hip implant design input parameters to focus on the most critical elements for a hip implant in the case of a total hip replacement. In addition, specific design input parameters are proposed including a wiring hole and distal slotted part, and analyzed using a finite element analysis method. The anatomical parameters in relation to a variation of the neck length are also analyzed in the same manner. To confirm the design parameters enabling normal hip implantation, a maximum neck shaft angle and length threshold model is implemented on the basis of the statistical average femoral configuration of Koreans and verified by a FEM (Finite Element Method) fatigue analysis. An analysis protocol aligned with international specifications as applied and a threshold for each of the aforementioned parameters set up to derive optimal design parameters. Finally, as a pre-operation planning tool, the parameters of choice are extracted from an X-ray femur image and reconstructed into a 2D/3D CAD model using a customized hip implant design software program, and the model stability is verified using a static FEM.