解剖型桡骨远端记忆聚合器的力学稳定性

Mechanical stability of anatomic distal radius Ni-tinol memory connector

目的:探讨解剖型桡骨远端记忆聚合器(anatomic distal radius Ni-tinol memory connector,ADRMC)的力学稳定性。方法:20根尸体湿桡骨标本分别制作成远端横断型骨折模型,以ADRMC或普通钢板(CP)固定,采用万能材料试验机和静态电阻应变仪进行环抱支轴向环抱力的测试和三点弯曲、扭转实验。结果:ADRMC环抱支产生的最大轴向环抱力为12.82MPa;三点弯曲实验显示,ADRMC组和CP组板对侧加压分别为(3.92±1.22)和(5.26±2.37)N·m,板侧加压分别为(3.32±1.14)和(3.14±1.06)N·m,侧方加压分别为(4.27±2.13)和(3.96±1.34)N·m;当扭转角度大于2°时,CP组的屈服扭矩明显高于ADRMC组(P<0.05)。结论:ADRMC在提供牢靠固定的同时,轴向环抱持骨有利于稳定,纵向加压及记忆效应的存在可显著降低应力遮挡率。

Objective:To explore the mechanical stability of anatomic distal radius Ni-tinol memory connector (ADRMC). Methods: Twenty wet cadaver radius samples were all made into inferior extremity fracture model and fixed by ADRMC or common plate (CP), then three-points bending and distortion experiments were carried out by electrical measurement. Results; The maximum axial encircle stress developed by encircle part of ADRMC on distal radius was 12. 82 MPa. The result of three-point bending experiment in ADRMC group and CP group :plate side loads were (3. 92±1. 22) and (5. 26± 2. 37) N · m,anti-plate side loads were (3. 32 ± 1. 14) and (3. 14±1. 06 ) N · m ,flank loads were (4. 27±2. 13) and (3. 96± 1. 34) N · m. When torsional angle was above 2·yielding load torsional moment of CP group was higher than that of ADRMC group (P<(0. 05). Conclusion;The distribution of ADRMC-deyeloped stress around the fracture line is rational,and axial encircle stress is beneficial for stabilizing fracture during earlier period. The longitudinal compression and memory effect can decrease the stress block rate after absorption of fracture line.