Department of Orthopaedics, The Affiliated Suzhou Science and Technology Town Hospital, Nanjing Medical University Suzhou, Jiangsu, PR China.
Department of Aerospace Manufacturing Engineering, College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, PR China.
Niger J Clin Pract. 2022 Sep;25(9):1476-1483. doi: 10.4103/njcp.njcp_1888_21.
This study aims to improve the geometric design of the distal cementless femoral prosthesis stem, thereby changing the stress distribution of the femoral prosthesis and reducing the proximal stress shielding and distal stress concentration of the femur, so as to obtain better bone growth and long-term stability.
Two geometric shapes of the femoral stems, namely, inverted hollow cone and cross-shaped bottom groove, are designed for the distal femoral prosthesis. The model is built based on the femoral computed tomography (CT) data of healthy volunteers, and the finite element method is used to analyze and calculate the stress distribution of the two femoral prosthesis stems.
According to the length and width of bottom "cross" groove, the stress values of the femoral region of the cross-grooved distal femur are divided into five groups, namely, group 1 (length 1:1, groove width 1.0 mm); group 2 (length 1:1, groove width 1.5 mm); group 3 (length 1:1, groove width 2.0 mm); group 4 (length 1:2, groove width 1.0 mm); group 5 (length 1:2, groove 1.5 mm wide). And the non-grooved group of the distal femur is designated as group 0. In the segment A, B, and C of the femoral region, the difference in the mean stress between group 0 and groups 1, 2, and 3 have statistical significance.
The bottom "cross" groove of the distal femoral prosthesis can change the stress distribution in the prosthesis-distal femoral region and reduce the stress concentration at the distal prosthesis. Wherein, the grooved design of length ratio 1:1 is more advantageous.
本研究旨在改进远端非骨水泥股骨假体柄的几何设计，从而改变股骨假体的应力分布，减少股骨近端的应力遮挡和远端的应力集中，以获得更好的骨生长和长期稳定性。
为远端股骨假体设计了两种股骨柄的几何形状，即倒空心圆锥和十字形底槽。该模型基于健康志愿者的股骨计算机断层扫描（CT）数据构建，采用有限元法分析和计算两种股骨假体柄的应力分布。
根据底“十字”槽的长度和宽度，将带有底槽的远端股骨的股骨区域的应力值分为五组，即第 1 组（长度 1:1，槽宽 1.0mm）；第 2 组（长度 1:1，槽宽 1.5mm）；第 3 组（长度 1:1，槽宽 2.0mm）；第 4 组（长度 1:2，槽宽 1.0mm）；第 5 组（长度 1:2，槽宽 1.5mm）。未开槽的远端股骨组指定为第 0 组。在股骨区域的 A、B 和 C 段，第 0 组与第 1、2 和 3 组之间的平均应力差异具有统计学意义。
远端股骨假体的底部“十字”槽可以改变假体-远端股骨区域的应力分布，减少假体远端的应力集中。其中，长度比为 1:1 的开槽设计更有利。
