Babaniamansour Parto, Ebrahimian-Hosseinabadi Mehdi, Zargar-Kharazi Anousheh
Department of Biomedical Engineering, Faculty of Engineering, University of Isfahan, Isfahan, Iran.
Biomaterials and Tissue Engineering Group, School of Advanced Technologies in Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
J Med Signals Sens. 2017 Jul-Sep;7(3):170-177.
After total hip arthroplasty, there would be some problems for the patients. Implant loosening is one of the significant problems which results in thigh pain and even revision surgery. Difference between Young's modulus of bone-metal is the cause of stress shielding, atrophy, and subsequent implant loosening.
In this paper, femoral stem stiffness is reduced by novel biomechanical and biomaterial design which includes using proper design parameters, coating it with porous surface, and modeling the sketch by the software. Parametric design of femoral stem is done on the basis of clinical reports.
Optimized model for femoral stem is proposed. Curved tapered stem with trapezoidal cross-section and particular neck and offset is designed. Fully porous surface is suggested. Moreover, Designed femoral stem analysis showed the Ti6Al4V stem which is covered with layer of 1.5 mm in thickness and 50% of porosity is as stiff as 77 GPa that is 30% less than the stem without any porosity. Porous surface of designed stem makes it fix biologically; thus, prosthesis loosening probability decreases.
By optimizing femoral stem geometry (size and shape) and also making a porous surface, which had an intermediate stiffness of bone and implant, a more efficient hip joint prosthesis with more durability fixation was achieved due to better stress transmission from implant to the bone.
全髋关节置换术后，患者会出现一些问题。植入物松动是导致大腿疼痛甚至需要翻修手术的重要问题之一。骨与金属的杨氏模量差异是应力遮挡、骨萎缩及随后植入物松动的原因。
本文通过新颖的生物力学和生物材料设计降低股骨柄的刚度，包括使用合适的设计参数、对其进行多孔表面涂层处理以及利用软件对草图进行建模。股骨柄的参数化设计基于临床报告进行。
提出了股骨柄的优化模型。设计了具有梯形横截面以及特定颈部和偏移量的弯曲锥形柄。建议采用全多孔表面。此外，对设计的股骨柄分析表明，覆盖有厚度为1.5毫米、孔隙率为50%的涂层的Ti6Al4V柄刚度为77吉帕，比无孔隙的柄低30%。设计柄的多孔表面使其能生物固定；因此，假体松动的概率降低。
通过优化股骨柄的几何形状（尺寸和形状）并制作具有介于骨和植入物之间刚度的多孔表面，由于从植入物到骨的应力传递更好，实现了一种具有更高耐久性固定的更高效髋关节假体。
