模拟全髋关节置换后股骨假体的稳定性

背景：国内外关于髋关节置换后股骨的压缩力学实验研究较多，因此研究髋关节置换后股骨的扭矩、扭转角、载荷-位移关系非常重要。对比分析传统型假体和解剖型假体的压缩、扭转力学特性，对于髋关节置换及人工假体的稳定性研究具有重要意义。目的：通过模拟髋关节置换后股骨的轴向压缩和扭转实验，对比分析传统型和解剖型人工假体的稳定性，为临床提供生物力学参数。方法：取股骨左右侧标本共12个，其中左侧6个标本保留股骨颈作为解剖型钛合金人工关节假体组，右侧6个标本去除股骨颈作为传统型钴铬钼人工关节假体组。分别将两组标本置于电子万能试验机工作台上，以     5 mm/min的实验速度对标本施加压应力，读取20，40，60，80，100 N时所对应的位移值。之后取两组标本，将标本两端置于扭转试验机夹头内，以1 (°)/s的实验速度对标本施加扭矩，读取5，10，15，20 N•m扭矩时所对应的扭转角值。结果与结论：在100 N外力作用下，传统型假体位移为(2.03±0.06) mm，解剖型假体位移为(1.83±0.05) mm；在20 N•m扭矩作用下，传统型假体扭转角为(21.7±0.7)°，解剖型假体扭转角为(13.2±0.4)°。解剖型假体在100 N作用下的位移和在20 N•m扭矩作用下的扭转角均小于传统型假体组，差异有显著性意义(P < 0.05)。提示解剖型假体和传统型假体具有不同的压缩和扭转力学特性，解剖型假体置入股骨后具有较好的稳定性。中国组织工程研究杂志出版内容重点：人工关节；骨植入物；脊柱；骨折；内固定；数字化骨科；组织工程

Stability of femoral prosthesis after total hip replacement

BACKGROUND:There are many experimental studies about compression mechanics of femur after hip replacement at home and aboard. Therefore, it is very important to study the torque, torsion angle, load-displacement relationship of femur after hip replacement. Comparing and analyzing the properties of compression and torsional mechanics of traditional-type prosthesis and anatomical-type prosthesis is of important significance for studying hip replacement and the stability of artificial prosthesis.OBJECTIVE:To compare and analyze the stability of traditional-type prosthesis and anatomical-type prosthesis by stimulating femoral axial compression and torsion tests after hip replacement, so as to provide biomechanical parameters for clinic practice. METHODS:Twelve specimens of left- and/or right-side femur were selected. The femoral necks of 6 left-side femur specimens were retained as the anatomical-type titanium artificial joint prosthesis group, and the femoral necks of the 6 right-side femur specimens were removed as the traditional-type cobalt-chromium-molybdenum artificial joint prosthesis group. The femur specimens in these two groups were respectively placed onto the electronic universal testing machine workbench and were imposed compression stress at the experimental  velocity of 5 mm/min. The corresponding displacement values were read under the force of 20, 40, 60, 80 and 100 N. And then, both ends of the femur specimens from these two groups were placed within the chuck of torsion testing machine, and were imposed torque at the experimental velocity of 1(°)/s. The corresponding torsion angle values were read under the torque force of 5, 10, 15 and 20 N•m.RESULTS AND CONCLUSION:Under the external force of 100 N, the displacement was (2.03±0.06) mm in the traditional-type prosthesis group, and (1.83±0.05) mm in the anatomical-type prosthesis group. Under the torque force of 20 N•m, the torsion angle values of traditional-type prosthesis was (21.7±0.7)°, and that of anatomical-type prosthesis was (13.2±0.4)°. The displacement under the external force of 100 N and the torsion angle values under the torque force of 20 N•m in the anatomical-type prosthesis group were all significantly less than those in the traditional-type prosthesis group (P < 0.05). These results suggest that traditional-type and anatomical-type prostheses have different compression and torsion mechanical properties. The anatomical-type femur prosthesis has a better stability than traditional-type femur prosthesis.